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Image Design
Rune Pettersson
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Image Design
The illustration on the cover is part of an image from my video
program “Life Patterns” presented at the first international ex-
hibition “The Video Show” in London, may 1975. My “multime-
dia project” was one of two invited contributions from Sweden.
Here, this picture represents design of images.
Permission to make digital or hard copies of all or part of this
work for personal or classroom use is granted without fee pro-
vided that copies are not made or distributed for profit or com-
mercial advantage and that copies bear this notice and the full
citation on the first page.
Institute for Infology
ISBN 978-91-85334-28-6
© Rune Pettersson
Sweden, Tullinge 2024
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Preface
Information design is a multi-dimensional, multi-disciplinary,
and worldwide consideration with influences from areas such as
design disciplines, communication disciplines, information dis-
ciplines, language disciplines, cognitive disciplines, art and aes-
thetic disciplines, business and law, as well as media production
technologies.
In information design the main functions of images are to
visualize, clarify, inform, attract attention, facilitate reading, ex-
plain, and convey information. The type of visual to be used in
the production of materials for information and learning must
often be determined in each case with a view to specific demands
on the visual, and also to the prevailing budget framework. Image
design is an important “tool” in message design. Pictures can be
used to facilitate attention, perception and mental processing
Visual presentation support is persuasive and may aid learning.
Since my retirement I have edited and revised sections of my
earlier books, conference papers and reports about information
design, message design, visual communication and visual liter-
acy. Previous editions of this book were published every year
2011–2023. When there is no information about the name of a
photographer, an artist, or a draftsman in a caption, that picture
is my own photo, or my own drawing or sketch.
Tullinge, Sweden
Rune Pettersson, Ph.D.
Retired Professor of Information Design
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Contents
Preface 3!
Contents 4!
Dots and lines 8!
Dots 8!
There are different dots 8!
Point and line by Kandinsky 10!
Lines 11!
Lines in art 11!
Different lines 12!
Lines in schematic pictures 17!
Areas 18!
Areas in art 18!
Areas in schematic pictures 19!
Volumes 21!
Image theories 26!
Providing clarity 27!
Image design perspective 27!
Legibility of pictures 29!
Legibility of signs and symbols 31!
Legibility of maps 32!
Providing emphasis 33!
Visual content 36!
Structure 37!
Degree of realism 37!
Degree of detail 40!
Factual content 42!
Content representations 42!
Objects 43!
Time and place 44!
Statistics 45!
Events 49!
Motion and rhythm 49!
Sound 50!
Humour and satire 50!
Emotions 51!
Symbolism 53!
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Viewer completion 53!
Execution of visuals 54!
Size 55!
Size of visual 55!
Size of subjects 56!
Shape 58!
Shapes and emotions 58!
External shape 59!
External contour 60!
Colour 61!
What we see 61!
Colour combinations 64!
Colour description systems 66!
Use of colour 70!
Contrast 75!
Texture 76!
Light 77!
Outer orientation functions 78!
Inner orientation functions 79!
Composition 79!
Organization 79!
Balance in pictures 81!
Centres of interest 81!
Direction 82!
Pictorial perspectives 83!
Line-based positional perspectives 84!
Area-based positional perspectives 95!
Other positional perspectives 98!
Psychological perspectives 99!
Picture editing 102!
Why picture editing 102!
Selection of pictures 103!
Cropping 108!
Changing scale 112!
Text in pictures 114!
Image manipulation 115!
Views on image manipulation 115!
Digital image manipulation 118!
A definition of image manipulation 128!
Image contexts 130!
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Internal context 130!
External context 131!
Personal context 132!
Image formats 134!
Image morphology 135!
Combinations of small elements 135!
Analogue and digital coding 140!
Computer images 142!
Creation of computer images 142!
Computer screens 148!
Graphical pictures 150!
Full-tone pictures 150!
Half-tone pictures 151!
Scanners 154!
Printers 156!
Printing 160!
Electro-press 168!
Copying 168!
Photography 170!
Film 172!
Television and video 175!
Television systems 175!
TV receivers 177!
High definition television 178!
Classification of visuals 180!
Classification systems 180!
The picture circle 184!
This is the picture circle 184!
Realistic pictures 186!
Suggestive pictures 186!
Symbols 187!
Schematic pictures 189!
Photographic portrayals 199!
Archives and image databases 201!
Collections and archives 201!
Simple indexing 202!
Systematic catalogues 202!
Large picture archives 203!
Indexing systems 205!
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Style 208!
Picture quality 211!
Measuring picture properties 211!
Before the original 212!
Before technical production 212!
After publication 214!
Technical quality 224!
ID Library 225!
References 226!
Appendix: Main concepts 240!
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Dots and lines
Unlike verbal language systems images and visual language
speak directly to us in the same way experience speaks to us:
emotionally and holistically. This chapter includes the following
main sections: Dots, Lines, Areas, and Volumes.
Dots
A dot is the smallest graphic element in visual language. A dot
may vary in size. The dot is usually a meaningless, or a non-sig-
nificant image element, but it may also be a syntagm, such as an
eye in a cartoon-face. A dot may even have a complete meaning,
such as a ball in mid-air. It all depends on the context, and the
situation depicted.
There are different dots
A dot is the smallest graphic element in visual language. A line
may be defined as a dot that is extended, at least to the length of
two dots, and usually into many more. An area may be defined
as a line that is broadened. Thus, the smallest line possible has
the length of two dots, and the smallest area possible has the size
of four dots. A volume has a three-dimensional form.
A dot (1) may vary in size. A line (2) may be defined as an ex-
tended dot, at least to the length of two dots, and usually into
many more. An area (3) may be defined as a line that is broad-
ened. Thus, the smallest line possible has the length of two
dots, and the smallest area possible has the size of four dots.
With respect to the technique and the different types of vis-
uals, dots can vary in colour, grain, position, shape, size, as well
as in value. Also, the context of dots will vary. A dot can provide
harmony or stress to a given composition.
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A point in mathematics
In mathematics, a point is a location, defined by the crossing of
two very thin lines. Any point has an exact position in a specified
context, an exact coordinate on a plane. The mathematical point
has no colour, no grain, no shape, no size, and no value. However,
for practical reasons the mathematical point is often represented
by a visible and printed dot.
Digital images
In work with digital images in computerized image processing
systems, graphic elements can be defined in one of two systems:
either mathematically as points and vectors, defined by Carte-
sian coordinates, or in the form of pixels (minute rectangular pic-
ture elements used in “building blocks”), defined by raster coor-
dinates. A vector can be assigned basic graphic properties in the
same way as attributes in display fountains, but it has as such
only mathematical properties. A pixel is in fact a minute area and
can vary with respect to colour. Dots, lines, areas, and symbols
(such as letters) are composed of several pixels.
Direction and motion
A group of dots may suggest direction and motion. The ability of
a series of dots to direct our attention is greater the closer the
individual dots are to one another. When the dots are really close,
they cannot be individually recognized any more. Thus, a series
of dots form a line. A line could also be defined as the “track of a
dot in motion” or as a “visual record of the path of a dot”.
Printed dots
In printing technology, graphic elements may be defined as type
for letters, and lines, and screen points for all kinds of pictures.
In the scanner a light beam “reads” all parts of the picture. This
information is converted to the raster-dots that are employed in
the printing of the picture. The photos we see in books and news-
papers are collections of printed dots. Further see the main sec-
tion Graphical pictures in the chapter Image formats.
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Visual fusion
When we look at a printed picture, a television image or an image
on a computer screen, our minds combine the dots by blending
and organizing the patterns into correct images. This subcon-
scious process is called visual fusion. When placed in patterns
known as “halftones,” printed dots are perceived as continuous
and solid values and hues. Further see the main section Graph-
ical pictures in the chapter Image formats.
Point and line by Kandinsky
The Russian pioneering painter Vassily Kandinsky (1866–1944)
was an influential modernist, and art theorist. Many consider
him to be the father of abstract art and a leader in the movement
to free art from the strict bonds of tradition. According to Kan-
dinsky, art is the expression of the spiritual atmosphere of a cer-
tain period. Art evolves from the culture that inspires artistic ex-
pression. The foundation of forms, the harmony of colours, and
the principle of art is an “inner necessity,” or a “right of the artist”
to her or his unlimited freedom. Art is born from the inner ne-
cessity of the artist.
In 1925 Kandinsky published his thoughts of the role of the
point, line, and other key elements of non-objective painting.
Here a point is a small bit of paint on the canvas. This point is
neither a geometric point nor a mathematical abstraction. It has
colour and a complex, or a simple shape.
A point can be isolated, but often it resonates with other
points or lines on the canvas. A horizontal line corresponds with
the ground. A vertical line corresponds with height and offers no
support. We perceive a diagonal line un-stable. Kandinsky taught
at the Bauhaus school of art and architecture from 1922 until the
Nazis closed it in 1933. Then Kandinsky moved to France.
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Lines
A line may be defined as a dot that is extended, at least to the
length of two dots, and usually into many more. Thus, the small-
est line possible has the length of two dots. A line may vary with
respect to its starting point, its brightness, colour, context, cur-
vature, direction, evenness, grain, length, orientation, positions
of change, printing, shape, thickness, value, and its terminus.
When the blue dots are close to one another they form a line.
Lines in art
Drawing is one of the oldest forms of human expression. Visual
art is a cognitive and creative activity. Lines in art are very old.
The oldest cave paintings have prints and contour lines of hands,
directly on the rock walls. The Funnelbeaker culture is the name
of an early Neolithic agricultural farming culture in Europe,
about 6 200–2 800 years ago. People in this archaeological cul-
ture decorated their pottery with lines and patterns. They used
tools for incising, impressing, modelling and stamping.
A “carving” or “engraving” is an image created by removing
parts of a rock surface by abrading, carving, incising, or picking
as a form of rock art. In North America this kind of rock art is
often called petroglyph. Scandinavian rock carvings were made
during a period of five thousand years (Nordbladh, 1999, p. 144).
Many early rock carvings consist of lines, carved and painted.
Drawing is the foundation of all forms of visual art and pic-
torial representations. It is often exploratory. Artists like Rem-
brandt (1606–1669), and Vincent van Gogh (1853–1890) are
well known for their interesting line drawings, and their prints.
It is often said that Pablo Picasso (1881–1973) was a “master of
line.” There is a special elegance in the way he expressed the to-
pography of the world.
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Different lines
There are many different kinds of lines, such as arrows, bold and
thin lines, connecting lines, diagonal lines, horizontal lines, ver-
tical lines, and many more.
Arrows
An arrow or a finger pointing at something leads your eye to it.
Lines that are meant to show a flow of events should display one
or two arrowheads that proceed from one picture element and
point to another. Arrowheads can have different forms. The con-
nection to the shaft can be concave, convex, or perpendicular,
and the length of the head often vary. To achieve unity, we should
avoid mixing various types of arrowheads in the same schematic
picture. Often the perpendicular connection works well enough.
Two-way arrows are only used for specific purposes.
See the article “Arrow (symbol)” at Wikipedia for presenta-
tions of a large number of ways to design and use arrows, from
the medieval convention of using a manicule (a pointing hand)
to modern needs.
Bold and thin lines
Artists often use several kinds of lines in the same picture. If all
lines have the same thickness and tone, the picture may seem
“lifeless” and it may be perceived as rather boring. It is possible
to show that something is important with heavy and thick lines.
A bold line is more powerful and strong than a thin line. Picture
elements with bold lines are perceived as more important than
picture elements with thin lines. A light and thin line is like a
“whisper.” A bold and heavy line is like a “shout,” or a “yell.” De-
pending on its boldness, and looseness a line may express a wide
variety of emotions.
Connecting lines
Lines that connect different picture elements or show a particu-
lar relationship in schematic pictures can be shaped differently
or placed in different ways. However, this should be done in a
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carefully prepared and systematic way. When lines connect to
other picture elements, the connection should be distinct, with-
out misleading “looseness.” Several parallel lines may be re-
quired for the connections. They may be similar or dissimilar.
Lines can link the geometrical mean-distance points of the
elements of a picture. This can be used for all types of geometrical
shapes: such as circles, diamonds, ovals, rectangles, squares, and
triangles. In the second method, the lines link together the focal
points on the sides of the picture elements. Linkage of the focal
points lends balance and harmony to the schematic picture.
In the third method, the points of linkage are equally distrib-
uted along the sides of the picture elements. This method is ap-
propriate for picture elements with right angles, but the method
is difficult to use if the picture elements are rounded in shape,
such as circles and ovals. Preferably, the various methods should
not be mixed–in any case, not in the same schematic picture.
Context of a line
A line can be a border between two areas in a visual. The line can
separate, and it can group picture elements. Since we always per-
ceive graphical elements with respect to their context, the mean-
ing of a simple and single line will vary a lot. A simple horizontal
line can serve, e.g., as a horizon, a street, or the surface of a sea.
A horizontal line can serve, e.g., as a horizon (left), a street (mid-
dle), or a sea (right).
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Diagonal lines
Often diagonal lines attract the eye and disrupt any harmony on
a page. Diagonal lines give the impression of movement in any
image. They create visual stress, and add
a feeling of depth to a visual. Diagonal lines
that reach out from one point in a number of
directions may be perceived as aggressive,
or even as something that is disturbing,
unstable, and maybe also violent.
Horizontal and vertical lines
Horizontal and vertical lines, parallel to the borders of the pic-
ture, give the impression of calm and stability. Horizontal lines
are restful and relaxing and they create a strong sense of equilib-
rium in any composition. Horizontal lines are perceived as being
shorter than equally long vertical lines (Thurstone and Carraher,
1966, p. 27). In accordance with Lanners (1973, p. 66) horizontal
lines seem shorter to us than vertical lines. It is easier for our eyes
to make horizontal than vertical eye movements. Vertical lines
also represent power, and often stop the eye movements.
The line (A) seems to be long when we compare it with a shorter
line (B), but it seems short when we compare it with a longer
line (C). Perception is relative.
There is a tendency for curved lines and smooth shapes to
stand out more than straight lines, and shapes made of straight
lines. Lines that reach out from one point in different directions
may be perceived as aggressive or even as violent. Straight or
curved lines tend to lead the eye along, and even beyond, the line.
Imagined lines
We should always be careful when we place graphical picture el-
ements in schematic pictures. An important factor to consider in
15
information design is: 1 + 1 = 3, or sometimes even more. Two
bold and heavy lines that run closely parallel to each other can
easily be interpreted as three lines, two lines in colour, with a
white line between them.
It is easy to see two blue lines here. But we may also see that
there are three lines here. In this case we see two blue lines and
one white line between the two blue lines.
Line drawings
There are several good reasons for using lines in drawing. Line is
the natural way to draw. Infants begin with line and adults con-
tinue with lines throughout life. Line drawings may be readily
recognizable. Line is a quick way to visualize ideas. Line needs a
minimum use of material and time. Line drawing materials are
least expensive. Line emphasizes the basic structure and compo-
sition of a drawing.
Line drawings are effective stimuli for learning, and most ef-
fective in formats where the learner’s study time is limited. More
realistic versions of artwork, however, may be more effective in
formats where unlimited study time is allowed.
In accordance with Richards (2017, p. 97): “it is a well-estab-
lished practice to use black-and-white line drawings to illustrate
texts describing maintenance or overhaul procedures presented
in manuals for technicians.”
Motion in a visual
The line is a powerful graphic element. Lines moving in the same
direction belong together. Most people, tend to follow a line
along its way. As a result, lines can be used to direct attention to
specific picture elements, and to many other things. The line pro-
vides the essential elements for perception of motion in a visual.
Since we read from left to right, and from top to bottom in the
western cultures most people here will see the upper or left end
16
of a line as its beginning and starting point, and the lower or right
end as the ending point or terminus. Artists may use this implied
motion when they wish to convey energy or action in their works.
Too many lines
When lines overlap or compete, emerging figures have good con-
tinuation. It is easy to interpret two lines that cross each other as
four lines. These lines may even be perceived as four triangles.
Too many lines can cause disturbing interference. Restrict the
number of lines to a minimum in each picture.
We perceive the pattern to the left (1) as two lines crossing in the
middle rather than as two opposing angles joined together at
their apexes (2 and 3). It could also be four independent lines
meeting in the middle (4).
The smallest effective difference
Tufte (1997, p. 73) suggested the design strategy of the smallest
effective difference: “Make all visual distinctions as subtle, but
still clear and effective.” For projection of visuals on screens the
corresponding gradation of line thicknesses is at least 1, 2, and 3
points. However, in a large auditorium, with a great distance be-
tween the screen and the people at the far end of the room we
may have to use 2, 4, and 6 points, or even thicker lines. In most
situations, we should avoid too bold lines.
According to Tufte (1997, p. 74) the idea of the “smallest ef-
fective difference” helps in designing the various secondary and
structural elements in display of accents, bevels, boxes, broken
lines for incomplete elements, captions, codes, compartments,
compass roses, dimension lines, fills defining areas and surfaces,
frames, grids, highlights, information—arrows, meshes, pointer
17
lines, rules, scales, shadows, tic marks, and underlines. Muting
these secondary elements will often reduce visual clutter—and
thus help to clarify the primary information.
Lines in schematic pictures
In may be important to differentiate between lines in illustra-
tions. We can’t easily distinguish between more than three, or
four lines thicknesses in a picture. However, as a guideline, it is
sufficient to differentiate between lines that illustrate different
kinds of information in a technical illustration with a three-step
gradation. In schematic pictures 0.5, 1, and 2 points may be suit-
able gradations for line thicknesses for documents printed in la-
ser printers, and then copied in office copying machines. The
number of line thicknesses may increase in printed materials.
In schematic pictures, we should usually use continuous
lines. We should avoid the use of various screen patterns, espe-
cially patterns that are screened diagonally. Lines should usually
be solid and continuous and not filled with a texture or screen
raster. Lines screened diagonally are often diffuse and indistinct
and are sometimes not legible at all. If screens must be used in
lines, the thickness of the screened lines should be at least 4
points, preferably even thicker, to be seen clearly in the printed
material. In projected images, we can use even thicker lines.
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Areas
An area may be defined as a line that is broadened. The smallest
area possible has the size of four dots. A line forming a shape may
describe an area. It may also be described by a colour, a shade or
a shape. An area may have an abstract, a geometric, or a repre-
sentational shape. Shapes may represent the real world in art.
Areas in art
One of the largest areas with rock carvings in Northern Europe is
Nämforsen (Larsson and Broström, 2018). Around 2,600 figures
and lines were carved or engraved into the rock surface during
the period 6 500–4 000 years ago. Here the most common mo-
tifs are mooses and boats. Many carvings have large carved and
painted areas.
An area can be varied with respect to brightness, colour, col-
our combinations, context, emptiness, grain, grey scale, shaded
or non-shaded parts, shape, size, texture, and value. Roundness
is the most common form in nature. When ink, water, or any
other liquid material is dropped on a surface, it assumes a
rounded and natural form. The size of an individual area is al-
ways relative. It depends on our knowledge of its surroundings.
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This picture shows a part of a large rock carving in the streams
at Nämforsen in Sweden. To the left there is a boat with hunters
arriving to the site. The boat has a bow designed as the head of
a moose. At least one hunter is already on land.
Artists like Joan Miro (1893–1983) and Olle Bærtling (1911–
1981) made paintings with abstract composition with large areas
in different colours and shapes. The American painter Chuck
Close (1940–2021) made some portraits using his own fingers as
painting tools. These pictures are constructed by thousands of
fingerprints in different colours.
Areas in schematic pictures
In schematic pictures, we should avoid using more than five col-
ours, grey tones, or screen patterns in different areas in the same
picture. Appropriate scales might be: white–grey–black; and
white–light grey–grey–dark grey–black. When the final produc-
tion is made with copying machines we should usually use only
the first of these two scales. To the extent that colours are used,
they should be clear and distinct, and they must be chosen with
great care.
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The size of an individual area is always relative. It depends
on our knowledge of its surroundings. The size of a single circle
means little to us. A hand gives the circle the size of a tennis ball.
Orange or yellow lines around the circle make it the gigantic size
of the sun.
Area principle
According to the principle of area we will interpret a small shape
within a larger shape as the “figure,” and the larger shape as the
ground. Our ability to distinguish the boundaries of an image is
usually very high. All elements in a visual should contribute to
clarity, the visual should be meaningful to the intended audience.
Basic geometric shapes
When small children are scribbling they make dots, lines and
endless open circular movements (Kellog, 1955). Already three-
year old kids may draw solid circles, triangles and squares (Bere-
felt, 1977). Circles, rectangles and triangles are all simple and
basic geometric shapes. They were used as important symbols
already in pre-historic cultures. Today simple and basic geomet-
ric shapes are used in many road signs. See some examples in
my book Reuse in A & D.
Most people can easily perceive basic geometric shapes with
a large degree of perceptual constancy despite changes in dis-
tance, viewing angle and illumination. In my view, we perceive
circles, triangles and squares/rectangles at a low cognitive level
without any special analysis (Pettersson, 1989). A square is an
example of a static area. A rectangle is perceived as a more active
area.
Negative space
Emptiness or space is the part of a visual that is not filled with
picture elements. This part of the picture is called “negative
space” or “passive space.” The negative space is usually the back-
ground. Empty space has no meaning in itself, but it may be used
to separate or bring together different picture elements. The
21
areas representing different objects are called “positive space” or
“active space.” The most important elements of the visual may be
emphasized to enhance attention and perception.
Volumes
A volume has a three-dimensional form. The form may be actual
or simulated. In two-dimensional representations of three-di-
mensional objects, shadows are key cues for simulated volumes.
We structure the three-dimensional field into various depth
planes, or grounds, a foreground, a middle ground, and a back-
ground. Like lines and areas, volumes also have several basic
properties, such as architecture, balance, colour, context, con-
tour, direction, form, gravity, light, material, position, propor-
tions, size, structure, stability, surface, and weight. Study the
works of recognised artists, painters, and sculptors. Most artists
use many of the possibilities in the visual language.
Michelangelo (1475–1564) was only 23 years old (1498)
when he received a commission to carve a Pietà sculpture in Car-
rara marble. The commission was “a dressed virgin Mary holding
the dead Christ in her arms, where both characters are of natural
size” (Geese, 1999, p. 226). The Pietà (1498–1501) in St. Peter's
Basilica in Vatican City is a masterpiece of Renaissance sculp-
ture. According to Santino (1985, p. 18) the pyramidal Pietà
shows a moment of supreme balance, exemplary beauty, har-
mony of feeling and attitude and classical finish, refined and per-
fect in the whole and in every detail.
Bernini (1598–1680) made his personal mark on an entire
epoch (Geese, 1997). He was a pioneer in the design of light,
movement, volume, and even sound. Bernini has been called “the
father of the Roman Baroque style.” Bernini was a leading person
in the emergence of Baroque architecture in the entire city of
Rome (Fagiolo, 2004). One of the most important of all Bernini's
works is the sculptural group L'Estasi di Santa Teresa (Ecstasy
of Saint Theresa, 1644–1652) in the Cornaro Chapel in Santa Ma-
ria della Vittoria, in Rome. Bernini designed the sculptural group
22
and the setting of the burial chapel in light, marble, stucco and
paint. Bernini shows the saint just in the highest moment of her
religious ecstasy (Honour and Fleming, 1991).
Auguste Rodin (1840–1917) possessed a unique ability to
work with clay. His first full-scale work The Age of Bronze (1876–
1877) shows a newly awaken young man who rises after sleeping.
The 181 cm high statue shocked the contemporary art audience
(Tucker, 1988, p. 17). Many people believed that Rodin had
simply made a plaster cast of a living young man and then cast
the statue in bronze (Laurent, 1986, p. 17). This statue had a
greater degree of realism than any human being had ever seen
before. Rodin worked the surface of his sculptures so that the
light emphasizes and explains their forms. He used the light
more efficiently than anyone else had done before him. Replicas
of his sculptures can now be found in many countries.
Constantin Brâncuşi (1876–1957) exploited Rodin’s discov-
ery of material as the fundamental determinant of form. He re-
placed the classic figure-modelling with the least possible pro-
cessing of wood and stone. He gradually removed all “unneces-
sary” details, and he used forms inherent in these materials. Ex-
amples of his works are The Kiss (1907–1908, 1908, 1909–1910,
and 1916). In the fourth and final version Brâncuşi utilized the
volume in a maximum way to create a powerful expression. This
limestone has the dimensions 58.4 x 33.7 x 25.4 cm.
Alberto Giacometti (1901–1966) was one of the most im-
portant sculptors of the 20th century. He was inspired by both
Braque and Picasso. In the 1940s Giacometti developed his per-
sonal, characteristic and very distinctive style with snapshots of
elongated, sketchy and thin human figures. He scraped away the
body's musculature and got very thin human figures combined in
various groupings. His style became a negation of all plastic vol-
ume. It is the direct opposite to Brâncuşi’s maximization of vol-
ume. The sculpture Man Pointing (1947) is 178 cm high. Giaco-
metti’s sketchy figures are as if engulfed in an infinite space.
23
The Romanian sculptor Constantin Brâncuşi (1876–1957) was
mainly active in Paris. He became a pioneer in the abstract
sculpture when he removed all “unnecessary details”. Examples
are the Kiss (1907–1908, 1908, and 1916). The last version
measures 58.4 x 33.7 x 25.4 cm. My picture from 2005 shows a
“synthesis” of my interpretation of Brâncuşi. I have seen the
sculpture, studied a large number of published photographs
and carved my own interpretation from a block of lightweight
concrete. My figure measures 17,5 x 10 x 7,5 cm. I photographed
my figure and then worked on the image on the computer, in the
format 20 x 14 cm, for high-quality colour prints.
24
The sculptor Alberto Giacometti (1901–1966) was born in Swit-
zerland. He was used to very long and thin shadows of people
in the mountains. During the 1940s he developed his distinctive
style. This became a negation of all plastic volume, and the op-
posite of the maximization of the volume that Constantin Bran-
cusi (1876–1957) worked with. My picture from 2005 shows a
synthesis of a large number of sculptures by Giacometti. I cre-
ated this image on the computer, in the size of 20 x 14 cm for
high-quality colour prints.
25
In the sculpture The Kiss, Constantin Brâncuşi utilizes the vol-
ume in a maximum way. My picture from 2005 shows a synthe-
sis of a large number of Giacometti’s sculptures, which can be
found in the Louisiana Art Museum in Denmark. These high
sculptures are negations of volume. I created this image on the
computer, in the size of 20 x 14 cm for high-quality colour prints.
26
Image theories
Aesthetics theories related to aesthetic proportion, study of
beauty, colour, harmony, and unity are presented in my book
Graphic design. Language theories related to diagrammatic lit-
eracy, digital visual literacy, graphicacy, and graphical literacy
are presented in my book Text design. Facilitating theories re-
lated to attention and perception are presented in my book Cog-
nition. Facilitating theories related to learning, and memory are
presented in my book Learning. However, all these areas of the-
ory are also concerned with images.
According to Palmer (1999, p. 46), a theory is an integrated
set of statements (hypotheses) about underlying mechanisms or
principles that not only organizes and explains known facts but
also makes predictions about forthcoming information and
news. A theory conceptualizes diverse phenomena and systema-
tizes our knowledge about them. A theory illustrates how and
why something is as it is. Lupton (2009, p. 6) noted that a theory
is all about the question why. The process of becoming a designer
is focused largely on how. I have used the following definition of
the concept theory (Pettersson, 2019, p. 28).
A theory is a branch of art, design or science that deals with
methods, principles, and proposed explanations that are still
subject to experimentation. A theory illustrates how and
why something is as it is. A workable theory requires ade-
quate knowledge of the specific discipline.
This chapter includes the following two main sections: Providing
clarity, and Providing emphasis.
27
Providing clarity
The legibility of a graphical message is determined by the tech-
nical design of texts and pictures, that is, their clarity. The infor-
mation designer will have to make the content stand out clearly
from the background. (See my book Graphic Design about legi-
bility of text.) This main section includes the following sections:
Image design perspective, Legibility of pictures, Legibility of
signs and symbols, and Legibility of maps.
Image design perspective
Before starting to design visual information, it is very important
to define how the illustrations shall be used in any design. We
need to decide if we will use artwork or informative photographs.
The most important factors seem to be informational and learn-
ing objectives and user characteristics. Visuals may not always be
really necessary but are useful in many situations. However, in
some situations, all kinds of pictures may be distracting. In these
cases, visuals should not be used at all.
In the design and production of visuals for instruction and
for learning, pictures must always contain the information they
are intended to convey. The visuals must be relevant to the situ-
ation. Without clear content, the visual will not be able to func-
tion well.
We should carefully define the objective of each individual
visual. What information or knowledge is the visual intended to
convey? Who is the sender? Who are the receivers? And in which
medium or media is the visual to be distributed? Cues for under-
standing the message in a visual are different in various cultures
as well as in different socioeconomic groups. It is important to
consider these factors.
From an image design perspective visual language, visual
content, visual context, execution of visuals, and image formats
are discussed in this book. Here are some facts, hypotheses, and
postulates that are based on image design:
28
• Visual languages have “analogue coding” employing combi-
nations of basic graphic elements (dots, lines, areas, and vol-
umes) for depicting reality. A given set of basic elements can
be combined to form completely different images.
• Visual languages attempt equivalence with reality. Visuals are
iconic and normally resemble the thing they represent.
• In visual languages meaning is apparent on a basic level, but
the visual language must be learned for true comprehension.
• Variables in visual language are related to content, context,
execution, and format. Content is more important than exe-
cution, context, and format.
• A “good” visual displays good legibility and good reading
value. It conveys information without ambiguity, is attractive,
and often aesthetically pleasing.
• A “poor” visual displays poor legibility and poor reading
value. It conveys information poorly, is seldom aesthetically
pleasing, and often ambiguous.
• Visuals may have many functions in communication. An in-
tended subject may be expressed through many different pic-
tures.
• Visual communication, visual language, visual learning, vis-
ual perception, and visual thinking are inextricably linked to
visual literacy.
• In visual literacy creation and interpretation can be said to
parallel writing and reading in print literacy.
• Visuals, graphic form and text should always work together to
fulfil information design objectives.
• Visual content can only be measured by subjective means.
• Visual messages are superior to verbal messages when con-
tent is emotional, holistic, immediate, spatial, or visual.
29
Legibility of pictures
A message has good legibility if it is easy to read, and if the reader
can easily see and distinguish all different parts of the message.
Legibility can be measured rather objectively and its quality is
assessable whether we understand the content of the message or
not. Dissatisfaction with the execution of a message may also
cause dissatisfaction with the content of the message. The infor-
mation designer has to consider the legibility of texts, printed on
paper, displayed and projected on screens, as well as legibility of
colours, legibility of layout, legibility of numerals, legibility of
pictures, and legibility of symbols. We should:
• Set words in images and pictures bold enough to read.
• Set words in images and pictures large enough to read.
• Use a style guide for picture elements in schematic pictures.
• Use picture elements that are bold enough.
• Use picture elements that are large enough.
A “good” visual has a high level of picture quality. It is well worth
reading and is executed so as to be legible and readable and be
displayed in an optimum context in an appropriate format. The
visual should convey information without ambiguity. It should
be attractive and stylish. It is often also aesthetically pleasing. A
schematic drawing has good legibility if it is easy to read, from
the viewpoint that the reader should easily be able to see and dis-
tinguish all the different parts of the schematic picture.
A “poor” visual has a low level of picture quality. It displays
poor legibility and poor reading value. It conveys information
poorly, is seldom aesthetically pleasing, and often ambiguous. A
“poor” visual has a low level of picture quality. It displays poor
legibility and poor reading value. It conveys information poorly,
is seldom aesthetically pleasing, and often ambiguous. Dwyer
and Dwyer (1989, p, 122) pointed out “the value of different types
of visual illustrations is not a valid assessment of instructional
effectiveness that is, aesthetically pleasing visuals may not be of
great instructional value.”
30
Here is a simple schematic picture with very poor legibility
(left). Unfortunately, this “style” is quite common in many tech-
nical illustrations. When colour is used in this kind of false
three-dimensional picture elements, legibility may be even
worse than in this example. It is really hard to read the message.
The second illustration (right) carries the same content. How-
ever, in this illustration it is easy to read the message. It has
very good legibility
Wileman (1993, p. 86) provided the following checklist with
questions for evaluation of visuals with reference to their clarity:
1. Are the words and images large enough to see?
2. Are the words and images bold enough to see?
3. Is there good contrast between figure and ground?
4. Is the visual appropriate for the intended audience?
5. What visual devices are used to direct the viewer's attention?
6. Does the visual contain only the essential information?
7. Are appropriate visual sequencing techniques used to present
complex ideas?
It is a good idea to use this checklist for text as well as for pictures
in order to achieve clarity of the message. Graphics and sche-
matic pictures can help readers see and comprehend complex
patterns (Horton, 1991). Visuals should contain essential infor-
mation and have a good contrast between figure and ground.
31
Legibility of signs and symbols
The use of symbols has a long tradition and various symbols can
be used to aid communication. We should:
• Design solid figures with a distinct contrast to the back-
ground.
• Use characters and graphical elements that are bold enough.
• Use characters and graphical elements that are distinct
enough.
• Use distinct colours to design symbols that will function in
any size.
• Use simple graphical elements to design symbols that will
function in any size.
A clear and stable figure to ground articulation is essential in
graphic symbols (Dewar, 1999; Easterby, 1970). The figure
(“foreground”) should be organised as one unit with close bound-
aries, appropriate line thickness and any other graphical means
that help the visual system to organise the figure as one unit. Cri-
teria for individual symbols or sets of symbols depend on their
application (Dewar, 1999). It is appropriate to use silhouette
(side) views of certain components such as vehicles. Complex
warning messages need a combination of pictographs and words
(Dewar and Arthur, 1999).
Legibility distance is essential in the case of traffic signs and
many building signs, but not for symbols on maps or consumer
products. Black text on a yellow background is superior as com-
pared to white on black, white on grey and black on white (Wal-
ler, 2007). For good legibility warning signs must have high con-
trast relative to the background (Barlow and Wogalter, 1991;
Sanders and McGormick, 1993). It must also be possible to see
warning signs in degraded conditions such as low illumination,
smoke, or fog (Lerner and Collins, 1983). Warning signs must
have adequate reflectance and good lighting (Sanders and
McCormick 1993). The choice of colour depends on the environ-
ment in which the warning sign is placed (Young, 1991).
32
Legibility of maps
Maps must have good legibility. We should:
• Provide distinct contrast in dimensions.
• Provide distinct contrast in form.
• Restrict the complexity of patterns.
• Restrict the number of typefaces.
• Use bold symbols in a consistent size.
• Use distinct symbols in a consistent size.
A graphic language used on maps consists of visual variables
(Baudoiun and Anker, 1984; Bertin, 1967). The most important
variables are position and place, form (of symbols), directions,
colour, density or greyness, granularity or texture, and size of
symbols. A variable can be a dot, a line, or an area. Discrimina-
tory responses to map symbols depend on contrast in form, di-
mension, and colour (Keates, 1982). The problem of discrimina-
tion is generally more critical in monochrome maps, in which
only contrasts in form and dimensions are possible for lines and
small symbols. Brumberger (2011) suggested that visual literacy
is particularly relevant in regard to maps.
The use of colour on maps introduces a large number of var-
iables, which may enhance contrast, and extend the number of
perceptual differences that can be employed in discrimination.
The effect is to aid legibility and increase the total range of infor-
mation which the map can present. Shape and colour compo-
nents are often used for designating a link or relationship be-
tween groups of messages. The recognition of geographical fea-
tures is much enhanced when areas are differentiated by hue. At
the same time, complex colour arrangements may raise problems
in discrimination, so that although multi-colour maps enlarge
the graphic possibilities, they also increase the probability of er-
rors in the judgment of discrimination. The most common case
of quantitative judgment on maps occurs in the use of propor-
tional symbols, that is, point or line symbols constructed to rep-
resent specific quantities.
33
Providing emphasis
Emphasis is used to attract or direct attention or dramatize cer-
tain points within a visual. A dark dot in a light field or a jog in a
line is both examples of emphasis. The contrast of the dark area
against the light background attracts attention to the dot. The
more dots, the lower the degree of contrast and the less effective
the emphasis. Many dots form a pattern of light and dark areas
that compete with each other. Neither shade dominates nor de-
mands more attention. The more competition for attention, the
less effective is emphasis.
Many different elements in a visual can cause emphasis.
Light against dark, colour against no colour, detail against no de-
tail, change in size, arrows, implied motion, circles or ovals
around objects, stars, shaded areas, tonal contrast, isolation,
complexity, directionality, line drawings in photos, words, posi-
tion or placement of elements, line intersections, or any other
unexpected change or variation out of context will create empha-
sis. Furthermore, emphasis on the message is achieved by reduc-
ing the number of details in the picture to those that are really
essential. Emphasis is achieved by reducing the number of de-
tails in the picture to those that are really essential.
Inappropriate use of graphical elements may direct learner
attention away from essential learning cues and depress subse-
quent achievement. To avoid disinterest and boredom, we should
use varied methods for emphasis. Explanatory words, numbers,
or other symbols should be incorporated into the picture as read-
ing aids when this facilitates comprehension and learning. These
aids must not then be distracting, large, or ugly. Simple styles
and fonts are more easily read than complex ones. Symbols are
of special value and importance in maps.
Relationships, moods, sound, and movements can be con-
veyed in a picture with the aid of signs and symbols. However,
symbols have to be learned by the readers. Usually they are not
naturally understood (Pettersson, 1993). Especially in develop-
ing countries, symbols must be introduced patiently, and slowly.
34
Letters of the alphabet, numerals, lines, arrows, circles, and
other symbols or markings can be added to a picture for the pur-
pose of enhancing image content and focusing attention to spe-
cific parts of the image and links to the caption. We should avoid
super-imposition of text on a picture image. This usually impairs
our ability to absorb the contents of both the text and the picture.
In audio-visual materials, such as slides, filmstrips, and
screen presentations, lettering must be considered carefully. Fif-
teen to twenty words on a slide is maximum for effective commu-
nication. Letters should be medium to medium-bold. Lettering
height should be no less than one twenty-fifth the height of the
artwork to be transferred. Generally speaking, lower-case letters
are more legible than capitals.
Many elements in a visual can be used to cause emphasis.
Some examples
Reference
Areas of shading
Mijksenaar 1997; Pettersson 1989
Arrows
Beck 1984; Hartley 1987; Jonassen and
Kirschner 1982; Lamberski and Dwyer
1983; Lohr 2010; Mayer 1993; Petters-
son 1989; Wileman 1993; Winn 1989
Asterisks
Wileman 1993
Change in size
Pettersson 1989
Colour
Lohr 2010; Mijksenaar 1997; Winn
1993; Wileman 1993; Wogalter 1999
Contrast, light/dark
Pettersson 1989
Imbalance
Fleming and Levie 1978
Implied motion
Lohr 2010; Pettersson 1989
Letters in pictures
Lohr 2010; Pettersson 1989; Wileman
1993
35
Line drawings in
photos
Lohr 2010; Pettersson 1989
Placement of ele-
ments
Lohr 2010; Pettersson 1989; Wileman
1993
Reducing details
Lohr 2010; Pettersson 1989; Wileman
1993
Repetition
Mayer 1993
Stars
Pettersson 1989; Wileman 1993
Typography
Lohr 2010; Pettersson 1989; Wileman
1993
Words in pictures
Pettersson 1989; Wileman 1993
36
Visual content
In the design and production of visual information, we have to
consider the characteristics of visual languages. We need to know
how the illustrations will be used. We should consider image var-
iables related to content, graphic execution, context, and format.
The island Lido is located South-East of Venice, Italy. The Lido
is an eleven kilometre-long, four km2 low sandbar. The highest
elevation is three meters. The island is indeed presented very
differently in these three maps, all without scales. As well as
other pictures, maps must obviously contain the data and the
information that they are intended to convey to the intended au-
dience. Here the maps are very much reduced in size. The island
Lido was 29 cm on my first map (top), and 48 cm on two other
maps. The third map gives us the best representation of Lido.
This chapter includes the following main sections: Struc-
ture, Factual content, Events, Emotions, Symbolism, and
Viewer completion.
37
Structure
A well-defined structure of content facilitates learning. There is
a need for structure in complete material as well as within parts
of the material. Normally the structure of an instructional mes-
sage is built to be continuous, to form a connected whole that
presents the message clearly to learners. The instruction pro-
gresses logically, step by step. After an initial orientation or in-
struction, instructional materials should develop at a pace that is
suitable for the intended audience.
When the learner doesn’t see, read, or hear what she or he
expects to see, or can’t find agreement between verbal and visual
content, the message is likely to be misunderstood. Since the
competition for our attention is very fierce in commercial arts
and in advertising, discontinuity is often used intentionally to at-
tract and even to hold attention. The intended message may be
hidden within verbal or visual puns, metaphors, satires, paro-
dies, or humour. In these cases, designers break the traditional
rules of instructional design. It might also be possible to use the
unexpected to attract attention to instructional material as well.
This main section includes the following sections: Degree of
realism, and Degree of detail.
Degree of realism
A visual should usually possess a moderate and selected degree
of realism and be true-to-life. Rather often this means culturally
accurate detailed drawings in natural colour. However, to a large
extent realism is determined by conventions. What is seen as re-
alistic in one culture may be seen as incomprehensible in another
culture. Brouwer (1995) noted that realism is determined by the
extent in which people consider something abstract or concrete.
Within a specific culture recognition of familiar objects is re-
markably high. But some objects, for example, a fire or a river,
are not readily described in line drawings.
According to Zimmer and Zimmer (1978), Cook (1980) and
Brouwer (1995) six factors determine the realism of an image.
38
These six factors are: colour, form, motion, perspective, recog-
nizable details, and scale. Illiterate people in rural communities
in Africa have problems with understanding the visual conven-
tions generally applied to these factors.
A photograph, which is clear in “Western eyes,” can cause
serious problems for a visually poorly trained person. A photo-
graph of a tree means an enormous change in scale. Understand-
ing of pictographic images and graphic symbols requires a con-
siderable set of conventions to be understood. Western viewers
have learned to separate the important stimuli from background
noise in pictures. This is, however, not at all the case with “illit-
erate people.” A woman wearing different clothes, with a differ-
ent hairstyle from people in the rural neighbourhood is not “one
of us” and her problem or her solution to a problem is therefore
seen to be irrelevant for many.
Just as the use of too many details, the use of too many col-
ours in a picture may cause problems. Colour is strongly associ-
ative and it draws attention. This can be either good or bad. A
“strange” colour may draw attention away from the important
content in the picture. Colours tend to either persuade or scare
off people. Because conventions differ from culture to culture, as-
sociations with a colour will differ as well. This became painfully
clear with the use of light blue packages of contraceptive pills in
certain parts of India, where this colour had the negative conno-
tation of constipation (Epskamp, 1981, p. 29). It is not possible
to depict movement well in pictures for illiterate people in rural
communities. Western conventions like “speed lines” need to be
taught. Otherwise they will not be understood.
39
Cartoons, line drawings, and photographs represent a contin-
uum of realism. These four levels of realism are needed in very
different situations.
In some cultures in Africa, the concept of perspective is not
understood (Brouwer, 1995; Zimmer and Zimmer, 1978). By
drawing in perspective some objects may be partly hidden be-
hind other objects. Then people with little or no pictorial experi-
ence often have difficulties in understanding these kinds of pic-
tures. The visual part of the object is being interpreted as the
whole object, or the object in the foreground and the object be-
hind it are seen as belonging together.
Illiterates may see a human head, or hand, without the rest
of the body as bloody, or just funny. Informative pictures should
be “unambiguous,” i.e., not be too “artistic” and too ambiguous.
Cartoons, line drawings, photographs in black and white, and
photographs in colour, represent a continuum of realism in vis-
uals.
Too little or too much realism in a visual can interfere with
the communication and learning processes. Learning is always
related to the needs of the learners and to the level of objectives
in each specific situation. Low-level objectives, such as naming
of objects, need only a limited amount of information. High-level
objectives, such as synthesis and analysis, need a lot of infor-
mation. Learners being exposed to “new” information may profit
optimally from line drawings, whereas learners who are familiar
with the content area may profit from more realistic types of il-
lustrations.
40
Degree of detail
Zimmermann and Perkin (1982) noted that it is important to
keep pictures as simple as possible. It is better to show a family
planning clinic set against a plain background than against a city
street. A crowded street will only detract from the message being
conveyed. However, while excessive, unnecessary detail inter-
feres with message understanding, comprehension may also be
reduced by excessive deletion of detail.
A visual should contain the details that are essential in com-
municating the intended message. Too many details and too
much complexity give rise to distracting “interferences” and re-
duce the interest for the content and the impact of the important
part of the content in the visual. Thus, we should avoid unneces-
sary elements in the picture. Too few details or too little complex-
ity makes it impossible to understand the picture. For each pic-
ture there is an optimal degree of detail. This depends on the con-
tent, the format, the intended audience, and the objectives.
The amount of information and the degree of detail should
be tailored to the medium and to the visual format. No more than
a dozen major points can be effectively covered in a single pam-
phlet. A single page of a booklet should not include too many ob-
jects, nor should it attempt to portray more than one single step
in a process. Each picture and each page should have a single,
sharp meaning. Multiple messages on one page will only confuse
the receiver.
Slides, overhead transparencies and power point presenta-
tions often include far too much information, making them im-
possible for the listeners to read, and comprehend in a short
time. It is usually not possible to directly transfer printed images
to slides or overhead transparencies. Pictures should be re-de-
signed to best fit the selected medium.
If necessary, we should use a series of visuals instead of only
one picture, that is overloaded with information. In a slide show,
“one-message slides” are usually the ideal. This is also true for
print material designed for children. A depiction of a sequence in
41
a series of frames should have a reasonable continuity. We are
able to perceive up to about seven stimuli at the same time (Mil-
ler, 1956). It has been found that 7+/–2 is a reliable measure of
human capacity.
A major factor in instructional effectiveness is repetition.
Also, summaries will help learners to remember the most im-
portant points of the specific subject matter. Background col-
ours, shades, frames, and special use of fonts and type size can
be used to achieve unity.
Objects and events perceived as different or as similar in any
way will be grouped and organized in our perception processes.
Learning is facilitated when critical cues are apparent. Avoid
non-critical cues if possible. In some cases, a number of details
in a picture or in a design may cumulate into larger coherent
structures.
Tufte (1990) noted that the Vietnam Veterans Memorial in
Washington D.C. achieves its visual and emotional strength by
means of a combined micro and macro design. From a distance
the entire collection of names of 58,000 dead soldiers arrayed on
the black granite yields a visual measure of what the figure
“58,000” actually means, as all letters of all these names blur into
a grey shape, cumulating to the final toll. When a viewer ap-
proaches, these shapes will resolve into all the individual names.
The same kind of micro and macro design is often used in the
design of posters.
42
Factual content
In instructional message design, the content is very often factual.
“Realistic” pictures can provide reasonably objective documen-
tation of an object or a product. This main section includes the
following sections: Content representations, Objects, Time and
place, and Statistics.
Content representations
One prominent norm of science images is the minimalist style –
realized through fewer colours (typically, black and white), sharp
lines, fewer details and no contextual features (Kress and van
Leeuwen, 2006).
In one study Westlund (2018, 2022) analysed 93 multimodal
compositions made by second year students in Swedish elemen-
tary classes (ages 7–9). All compositions were produced during
five teaching sessions with science content. The topics were:
Heart and lungs; Lungs, heart and blood; Mushrooms; Space;
and Stars. The texts were mainly written on computers. The im-
ages were either made by the children, or added as ready-mades,
found on Internet. The compositions were evaluated as single
units of text and image.
Data processing was carried out with a social semiotic mul-
timodal analysis, focussing on images and relations between im-
age and writing. A social semiotic analysis of the student compo-
sitions resulted in descriptions of seven multimodal representa-
tions of content used for making meaning about science content:
• Art. Here content is abstract, experimental shapes, sensory,
and/or vibrant colours.
• Attitude-evoking. Here the author explicitly reveals her or his
attitude towards the content.
• Cultural heritage. Here the content has a metaphoric mean-
ing instead of a scientific meaning
• Event. Here content is movements, perspectives, and pro-
cesses.
43
• Natural experience. Here content is as it would be seen with
one’s own eyes.
• Person. Here content is anthropomorphized, with attribution
of human emotions, form, intentions, personality, and traits
to non-human entities. This is considered to be an innate ten-
dency of human psychology.
• Theory. Here content is reduced to its most general aspects.
These seven content representations occur both separately, and
in different combinations among the compositions made by the
student. The discussions are relevant for assessing and teaching
visually oriented science literacy in the early school years.
Objects
The type of subject should be commonplace, easy to recognize,
and neither uncommon nor abstract. Visuals should not contain
strange or unknown codes. Visuals are more likely to be success-
ful if facial features, clothing and buildings are based on what is
familiar in that society. The more familiar a message is to its au-
dience, the more readily it is perceived (Zimmermann and Per-
kin, 1982). Familiarity with the depicted objects themselves is
basic to understanding. Also, the purpose of the visual should be
obvious to the readers for whom the message is intended.
In developing countries, pictures of entire persons are most
easily understood by the intended receivers. Parts of the body
like arms, hands, legs, and feet are more difficult to recognize.
Even more difficult to recognize are tools and objects in the en-
vironment. People should, however, be dressed appropriately.
Facial resemblance to members of the community is often an ad-
vantage. Zimmermann and Perkin (1982) pointed out that infor-
mation material produced for national distribution might not be
equally appropriate for all geographic areas.
Select a wide variety of examples as well as a variety of non-
examples to enhance concept learning. In the examples the criti-
cal attributes should show as little variation and be as obvious
44
and typical as possible. The non-critical attributes should show
much variation and be as non-obvious and non-typical as possi-
ble. Objects and pictures of objects are better remembered than
their names.
Time and place
A still picture is a “frozen moment in time.” We d0n’t know what
happened before or what will happen. The passage of time is best
illustrated with a series of illustrations that show details in the
course of an event. However, illiterate people in developing coun-
tries may have difficulties in understanding that adjacent frames
show the same people in a time sequence.
Picture context and picture composition may illustrate an
age, a year, a season, and the time of day. We can enhance com-
prehension with captions. Sometimes a time-scale may be useful.
For AV productions the perception of time durations and time
intervals is relatively inaccurate without a standard or frame of
reference. Time that is filled with activity appears to pass more
rapidly than time that is not filled with any activity. Time is an
essential factor in television and film. We can distinguish be-
tween objective time (clock time) and subjective time (perceived
time). People seem to prefer programs with fast pace and action.
Location of objects may be important, and may be shown in
various kinds of drawings, graphs, maps, and scales. Time is a
dimension that is common to many application domains such as:
biography, biology, business, engineering, history, medicine,
planning, project management, and science. Understanding of
time-oriented data enables us to learn from the past in order to
predict, plan, and build for the future.
Appropriate visual and analytical methods are required to
explore and analyse them. Aigner et al. (2011) presented more
than hundred visualisation techniques with respect to the nature
of the dimensions of time, the character of the data, and the prop-
erties of the visual presentations. The TimeViz Browser provides
45
a visual survey of techniques for time-oriented data (Tominski
and Aigner, 2017).
Statistics
Numeric data are often used to illustrate situations such as rela-
tionships between variables and parts of a whole. Data can be
presented in many formats. Graphical formats include compari-
sons of areas, lengths, numbers, positions, volumes, and also
sometimes comparisons of different combinations of these vari-
ables. Discriminations are most readily perceived and learned
when the differences between stimuli are maximal.
The three bar graphs in this illustration contain the same data,
but they provide us with very different impressions. Bar graphs
can easily mislead the viewers, and some people use this.
It is far too easy to convey misleading information and even
disinformation about statistical relationships by misuse of
46
illustrations, and scales that are difficult to understand. We
should use a scale break only when it is necessary. If a break can-
not be avoided, the break must be distinct and easy to under-
stand.
Graphical excellence
If you wish to be clear, choose clear examples. Tufte (1983) wrote
(p. 51): “Graphical excellence is that which gives the viewer the
greatest number of ideas in the shortest time with the least ink in
the smallest space.” Quantitative information should be made to
stand out from the supporting information by ensuring that the
different items on a graph are easily distinguished visually.
Relationships between variables
It is easy for us to distinguish between lines. When relationships
between variables are to be presented, comparisons of lengths
give the best results. However, it is not at all easy for us to com-
pare sizes of areas or volumes.
In most contexts, the difference in the sizes of circles, ellip-
ses, squares, triangles, and several other two-dimensional geo-
metrical shapes are underestimated. At the University of Athens
research indicated that not all college students could accurately
interpret data from a chart or a graph (Malamitsa, Kokkotas, and
Kasoutas, 2008).
Cerreto and Lee (2012) asked entering college students to
use numerical data in tables and create graphs. These subjects
performed well when drawing comparisons, and they performed
fairly well when showing parts of a whole, or trends. The students
used appropriate types of graphs, and they drew them fairly ac-
curately. The subjects scaled the axes fairly well. However, the
subjects did not label the graphs well and they did not write good
explanations. There were moderate to strong correlations be-
tween all pairs of graphing task scores. There were weak or insig-
nificant correlations between math and verbal scores.
47
Distorting graphs by adding an artificial perspective, or add-
ing shadows, will often make it harder for readers to interpret the
information in a correct way.
Parts of a whole
It is easier to assess “parts of a whole” than “relationships be-
tween variables.” When parts of a whole are to be presented, cir-
cle charts and pie charts may be used. However, don’t use too
many segments. The bars in a bar chart should be equidistant
from one another, and the bars should be wider than the empty
spaces between them.
Design of individual graphic elements is important. Patterns
of bars should be discrete and not disturbing. Usually it is better
to avoid mixtures of patterns and keep the bars as plain as possi-
ble. If stacked bar charts must be used, it is best to have dark
tones at the bottom and successively lighter tones on top.
Friendliness of graphs
Tufte (1983) provided guidelines for the friendliness of graphs.
Here words are spelled out, and in western societies they run
from left to right. Data are explained. Shadings are avoided. Col-
ours are easy to distinguish, type is clear and precise, and set in
upper and lower case with serifs. Abbreviations abound in un-
friendly graphs. Words run vertically and in several other direc-
tions. These graphics are both cryptic and repellent, and they
have obscure coding, or coding’s. The design is insensitive to col-
our-deficient viewers. Sadly, red and green are used for essential
contrasts, and type is clotted and in all capitals in sans serif.
In accordance with Tufte (1983), excellence in statistical
graphics consists of complex ideas that are communicated with
excellent clarity, efficiency, and precision. Graphical displays
should (p. 13): 1) Show the data. 2) Induce the viewer to think
about the substance rather than about methodology, graphic de-
sign, the technology of graphic production, or something else. 3)
Present few numbers in a small space. 4) Make large data sets
coherent. 5) Encourage the eye to compare different pieces of
48
data. 6) Reveal the data at several levels of detail, from a broad
overview to the fine structure. 7) Serve a reasonably clear pur-
pose: description, exploration, tabulation, or decoration. 8) Be
closely integrated with the statistical and the verbal descriptions
of a data set.
Graphical competence
Good designs are intriguing and curiosity provoking, and actu-
ally “drawing the viewer into the data”. Tufte (1983) found that
graphical competence demands three quite different skills (p.
87): the substantive, statistical, and artistic. Yet most graphical
work today, particularly in news publications, is under the direc-
tion of but a single expertise–the artistic.
Allowing artist-illustrators to control the design and content
of statistical graphics is almost like allowing typographers to con-
trol the content, editing, and style of prose. Substantive and
quantitative expertise must also participate in the design of data
graphics, at least if statistical integrity and graphical sophistica-
tion are to be achieved. Tufte (1997, p. 48) argued that “good de-
sign brings absolute attention to data”.
Cifuentes, Myers and McIntosh (1998) noted that photo ma-
nipulation and stylistic embellishment might be used to create
dishonest figures and tables. Both designers and readers must be
mindful of possibilities for honesty and dishonesty in graphic
messages. However, by applying various methods of data analy-
sis and representing data graphically, information designers can
convey a message in different ways without jeopardizing the in-
tegrity of the message. For example, when using probability sta-
tistics, the information designer needs to carefully explain the
appropriate interpretation of the representations that are used.
Tufte 1997: “Good design brings absolute attention to data.”
49
Events
Several kinds of image content are related to events. Action, hu-
mour, drama, violence, time displacement, parallel action, met-
aphoric descriptions (symbolic actions), and change are all ex-
amples of events that may be the main content in visuals. It is
known that pictures showing events usually are perceived more
interesting and more effective instructional materials than static
pictures. Obviously, an activity is best shown in moving pictures.
This main section includes the following sections: Motion and
rhythm, Sound, and Humour and satire.
Motion and rhythm
The best way to illustrate motion in a still picture is to depict a
natural movement in a clear contrast to a static situation. In the
West, we read not only words from left to right, but also contrast,
movement, and story. When a person walks across an image from
left to right, he/she is going forward. Walking from right to left
means he/she is going backward.
We can show movement with a series of still pictures. These pic-
tures show how a hare moves in full speed.
In a still picture the impression of motion can be enhanced
with motion symbols such as speed lines that are common in
comic strips. The meaning of these symbols has to be learned.
Animation is common in several media, like computer games and
video. Movements are very powerful and attract our attention ef-
fectively. Other information may be unseen and lost. The relation
of figure to ground is particularly determinative of motion per-
ception, which is highly related to our perception of depth. Per-
ception of motion is influenced by contextual variables. Rhythm
consists of regular changes of a variable, arrayed into groups.
50
Sound
The impression of sound in a still picture is most readily con-
veyed with onomatopoetic combinations of letters combined
with graphical symbols and captions. In AV productions, words
and sound effects can enhance perception of the visual stimuli.
However, there should be a redundant relationship between
these different stimuli.
This picture illustrates some examples of onomatopoetic combi-
nations of letters.
Humour and satire
Humour as well as satire is often used in cartoons to point out a
special situation, an occurrence, or an event. In instructional ma-
terials humour may sometimes be used as a visual pun to attract
attention to the content or dramatize certain portions of a visual.
Humour has been shown to “increase the rate of learning,
improve problem solving skills, heighten retention, reduce nerv-
ousness, and increase perceptions of teacher credibility” (Roesky
and Kennepohl, 2008, p. 1358). Tatalovic (2009) discussed the
complicated concept “wind energy literacy” and argued that it
can be made more accessible to the general public is through
comics and cartoons.
Humour should always be used with great care in any mate-
rial for information. Misuse of humour and “funny people” may
ruin the intended message. This is sometimes referred to as the
“vampire-effect.” Satire should usually be totally avoided in ma-
terials for information and learning.
51
Emotions
Visuals may express relationships between people. In various
cultures the distance between people tells the viewer a lot about
their relationships; if they are friendly or hostile, and if they trust
each other. Pictures have a strong emotional impact (Kimball
and Hawkins, 2008; Kostelnick and Roberts, 2010).
As previously noted a dot or a simple line may have widely
varying meanings in a pictorial presentation. To illustrate this,
six copies were made of a simple drawing, about six cm high (Pet-
tersson, 1984). Drawing one was left completely unchanged. The
mouth was changed in drawings two to five by the addition of
small lines that completely altered the perceptions of the con-
tents in the illustrations. In drawing six a small line was added to
the hair, but this addition has no effect at all on our perception
of the content in the illustration.
These six pictures were shown, one at a time, to 20 children,
three to ten years old. Each picture was about six cm high.
A research assistant showed the six pictures, one at a time,
to 20 children, nine girls and eleven boys. The children were
three to ten years old. The assistant asked each child to look care-
fully at each drawing, and then tell her how he or she interpreted
the content. Children gave seven different views regarding the
drawings two to five. The most common answers for drawing
three were: sulking (14), followed by angry, bad, bored, don’t
know, and well (all 1). The children gave four different views re-
garding drawing four. The most common answers were: happy
(12), well (4), and don’t know, moderately happy, rather happy,
and sad (all 1).
52
Children interpreted different emotions in the six pictures.
A picture is able to express emotions in at least three differ-
ent ways. A picture may suggest an image of some emotional con-
cept. It may look like what an emotion feels, for example “happy”
or “sad.” A picture may arouse emotional response in a viewer.
S/he may feel excitement, fright, or pleasure. A picture may also
express and reflect the picture creator’s private feelings about a
given subject, such as politics or religion. Read about emotional
design in my book Learning.
Prawitz (1977) described how children become very excited
when exposed to colourful, irregularly shaped painting. Visuals
with an emotional content extend and support the attitudes that
we already have. Pictures will usually not change our attitudes,
but they make us more convinced that we already hold the “right”
views. If people like the content in a visual, they like it even more
when the visual is presented in colour and vice versa.
In the western cultural sphere, people tend to associate col-
ours with emotions or moods in the following way. The red and
yellow part of the spectrum is often said to be warm and is felt to
be active, exciting, happy, and clear. Green to blue is described
as cold and are perceived as being passive, comfortable, con-
trolled, and peaceful. Emotions and moods are readily conveyed
with onomatopoetic combinations of graphical symbols. How-
ever, we have to remember that the meaning of the symbols must
be learned by the readers to make any sense.
People tend to associate colour with emotions or moods.
53
Symbolism
There is often a major difference between the denotation, the lit-
eral meaning, and the connotations, associative meanings, and
private associations. Many visuals have a symbolic content and
meaning. Look at images used in advertising, in folklore, in my-
thology, in political campaigns, in propaganda, and in religions.
Some contemporary paintings and photographs are well known
by people all over the world. A photograph with a national flag is
much more than an ordinary photograph. To every person the
flag of her or his nation is a symbol that means “my country.” A
dove with an olive branch symbolizes peace, a lamb suggests gen-
tleness, and a lion is the symbol for courage. Sometimes symbolic
pictures are simplified to symbols. Visual details are reduced to
a minimum. A symbol cannot have detailed information.
Viewer completion
Experienced artists omit details in their pictures. They have the
ability to simplify, and in the process, expose significance. They
only draw the lines that are necessary to understand the intended
content. Our minds constantly fill in a lot of missing details and
we complete images, most of the time without our realizing that
it has happened. The most probable interpretation of the mes-
sage is created as a meaningful whole.
Some lines are more important than other lines. We make the
best possible interpretation of any given stimulus.
However, the human imagination may be triggered by the
design to provide details that will increase viewers’ attention and
possibly also facilitate learning. In drawings the lines that are
missing may be as important as those that actually are there.
54
Execution of visuals
Informative pictures should always be designed so they are easy
to read for the intended audience. The goal should be clarity of
communication. Several authors have argued: “Form follows
function.” Industrial products are often shaped by what they do.
To make life easier we want to have products with as good a func-
tion as possible. However, in message design the subjective tastes
of the individual designers are often allowed to dominate, some-
times with a serious malfunction as a result.
According to Riley (2008) drawing is the basis for the devel-
opment of an “intelligence of seeing”. Visualcy is an articulacy
with the language of drawing that distinguishes the visual arts
from other disciplines. The two authors Howard Riley and
Michelle Darlington discussed the status of drawing pedagogy
across the UK education system. The faculties of literacy and nu-
meracy are universally recognized as worthy of pedagogical nur-
turing. Riley & Darlington (2022) argue that drawing is funda-
mental to a visual arts pedagogy at all levels, and for its own
sake, since it is the basis for the development of an intelligence
of seeing. The potency of visualcy is still to be fully recognized
and realized across curricula devised by educationalists labour-
ing under a limited awareness of the educational and cultural
centrality of drawing. The concept of visualcy is very similar to
the concept of visual literacy.
This chapter includes the following main sections: Size,
Shape, Colour, Contrast, Texture, Light, Composition, Pictorial
perspectives, Picture editing, Image manipulation, and Image
contexts.
55
Size
It is easier for us to distinguish between lines than between areas
or volumes. When we judge the size of objects, e.g., areas, we are
apparently most influenced by the length of horizontal lines or
horizontal distances. In most contexts the differences in the sizes
of circles, squares, triangles, ellipses and other two-dimensional
symbols are underestimated. Size constancy is our tendency to
judge the size of an object as the same despite changes in dis-
tance, viewing angle, and illumination. This main section in-
cludes the following sections: Size of visual, and Size of subjects.
Size of visual
In materials for information, the size of a visual should never be
decided with respect to “available space” or “prettiness,” but with
respect to the possibility to communicate the intended message.
For example, illustrations in textbooks for early grades are both
large and frequent. In later grades the visuals are smaller and less
frequent. McDougall and Hampton (1990, p. ix) concluded that
photographs should be presented in arrangements and sizes that
attract and hold reader interest. Quite often readers will interpret
the size of a visual as a measure of importance. By tradition the
bigger a picture is on a page the more important it is considered
to be. However, a visual should neither be too small nor too large.
There is an optimum size for every visual. This size can only be
established by trial and error. The size must be large enough for
the image to be legible. A visual with a “large content” and many
details must be larger than a visual containing a more limited
amount of data. If two different sized pictures of objects are
placed next to one another, one is perceived to be near the viewer
and one farther away. Or the objects are perceived as being of
different sizes.
If one picture is larger than the others in an array, this pic-
ture will attract the most attention. “Noise” in the visual results
in a need for a larger size. A picture that is four to five centimetres
(one and a half to two inches) wide in a book corresponds to the
56
eye’s perception of the width of a TV screen at a normal viewing
distance and is adequate in some cases. In television the specta-
cle of things is de-emphasized, but human actions gain promi-
nence. A large Cinemascope image is more overpowering than
the small television image. In film, people as well as objects at-
tain spectacular dimensions. Increasing the size of illustrations
by projecting them does not automatically improve their effec-
tiveness in facilitating the achievements of the learners.
Size of subjects
The most important part of the subject must be large and clear,
take up a large proportion of the image area, and be perceivable
as an entirety. Large visual elements in a picture attract the at-
tention of the reader. The perception of size is influenced by col-
our and grey scale. Open and light forms are perceived as being
larger than closed and darker forms of the same shape.
These six circles all have the same size, but we may perceive
them as different because of the variation in grey levels.
The perception of size is very much influenced by contextual
variables. There can be no large without small, and no small
without large. We need to show the scale and the contrast within
an illustration. It is usually a good idea to include some familiar
object, like a person, a tree, or a car to supply the scale for judging
the size of an unfamiliar object.
57
Compare the size of the two
red circles. The perceived size
of an object is relative to the
size of nearby objects. The red
circle is actually equal in
both contexts.
People vary greatly in their ability to perceive proportional
relationships. The perceived size of an object is relative to the size
of other objects. The size of unfamiliar objects is perceived as rel-
ative to the size of familiar objects. Sometimes it is possible to
include a scale in the visual. Any simple and distinct part of an
image can be visually superimposed to measure proportional re-
lationships of the whole.
In caricatures, however, proportions are deliberately wrong.
Deliberate distortions create aesthetic tension between the cari-
cature and the normal image of the subject. This induces emo-
tional responses in viewers. Feelings are readily aroused by a de-
parture from what is considered visually correct or normal. Pho-
tographers can also produce “caricatures” by using unusual an-
gles and/or distorting lenses. When we need visuals for instruc-
tion, caricatures are usually not the best choice. When the size of
an object changes in a story from one page to another or even on
the same page, children up to seven years of age often believe that
the objects are different.
The perception of size is related to perceived distance, and
the perception of distance is reciprocally related to perceived
size. Regardless of distance there is constancy in the perception
of the size of known objects. This is called size constancy. (See
the pictures in the section Line-based positional perspectives
later in this book.)
58
Shape
When small children are scribbling they make dots, lines, and
endless open circular movements (Kellog, 1959). Already three-
year old kids may draw solid circles, triangles and squares (Bere-
felt, 1977). In my view, we perceive circles, triangles and squares
on a low cognitive level without any special analysis (Pettersson,
1989). This main section includes the following sections: Shapes
and emotions, External shape, and External contour.
Shapes and emotions
Due to their simplicity circles, triangles and squares are often
used as icons or symbols in modern communication, and as pic-
ture elements in schematic pictures. However, this simplicity
also means that different persons perceive simple shapes in
many ways. Functional, instructive graphic symbols are probably
older than words, and they are probably found in every culture
however primitive.
The circle, the equilateral triangle, and the square express
visual directions. Circles suggest curved directions, triangles sug-
gest diagonal directions, and squares suggest horizontal and ver-
tical directions. Shapes can be made in a number of ways. They
may be defined as the outlines of objects, or parts from different
objects. Shapes may also exist as gaps, or “negative space” be-
tween objects.
Irregular and unpredictable shapes dominate over basic and
regular shapes. Unpredictable shapes attract more attention
than basic and regular shapes. Most people can easily perceive
the basic shapes, and there is a large degree of perceptual con-
stancy in the perception of shape. Shape constancy is our ten-
dency to judge shapes as the same despite changes in distance,
viewing angle, and illumination. This is one of the reasons that
shapes, like the circle, the oval, the triangle, the square, the rec-
tangle, and the rhombus often are used in symbols and icons.
For small children (three to six years), colour stimuli have
greater impact than shape stimuli. However, the reverse is true
59
of older children, i.e., shape becomes more important than col-
our. There is a considerable difference between the interpreta-
tion of symbols by subjects, and the intended meanings. There is
no natural, spontaneous and unambiguous correlation between
colour and shape. However, many persons have a spontaneous
and emotional response to shapes. Some people view a square as
dull, straight forward, honest, and stable. The triangle may be as-
sociated with antagonism, arrowheads, cracked ice, danger, fire,
thorns, and twisted metal.
Our presumed connections between shapes and emotions
are utilized by the advertising industry. Based on the stereotypes
about women and men bottles holding women’s perfume are
generally oriented to circular, and triangular shapes. A soft bottle
shape is presumed to reflect the actual female body, and imply a
feeling of sensuality and warmth. A triangular bottle is presumed
to imply challenge, excitement, and risk. Bottles holding men’s
cologne are generally rectangular in shape. This shape is pre-
sumed to imply reliability and strength.
External shape
The picture area in drawing, painting, and still photography can
have any shape and any orientation. Most pictures, though, are
cropped and published in square or rectangular formats. How-
ever, the visual’s external shape should actually rather be “free-
form,” round, or oval, and not delineated by straight lines. Per-
ception of shape is influenced by contextual variables.
Classical formats are based on the proportions of the golden
section or golden rectangle, 3:5, 5:8, 8:13, 13:21, 21:34, etc. The
proportions of the golden section are 1:1.618. Since we basically
experience the world on a horizontal, rather than a vertical plane,
projection and television screens are horizontally oriented.
When HDTV was developed it was found that people preferred
the aspect ratio of 3 x 5 (the golden rectangle) or 9 x 16 (1:1.778)
rather than the then traditional 3 x 4 (1:1.333) ratio of television
systems.
60
These are golden rectangles. An interesting result of the golden
rectangle’s proportions (left) is that if we draw a square (yel-
low) inside the rectangle using the short side of the rectangle as
the side of the square, the remaining area (blue) will also be a
golden rectangle. This process can be repeated indefinitely.
External contour
The visual's external contour should be blurred and unclear so
the visual fades in and out of the background and never clear
enough to stand out against the background. (However, as noted
earlier the figures in the image must be clear and distinct.) A
printed image should fade in and out from the (white) page and
a projected image should fade in and out from the (dark) screen.
It is possible that very distinct framing diverts interest from the
actual content in the visuals.
Illustrations in early European books frequently had gently
rounded contours. Many artists still often draw free-form visuals
which are not delineated by straight lines and which fade in and
out of the background. In one study primary school textbooks
from Ghana, Japan, and Sweden were compared. Irregularly
shaped, oval, or round image shapes were predominant in the
Ghanaian and Japanese books. In the Swedish book less than
one-fourth of the illustrations were “free” or rounded images.
61
Colour
We can describe colour in aesthetic, physical, physiological, psy-
chological, and technical terms. Intensity, purity, and wave-
length are physical dimensions. Hue, saturation, and value de-
scribe what we see. Colour communicates, and it is a language of
its own to some extent. Colour is an important part of infor-
mation design. This main section includes the following sections:
What we see, Colour combinations, Colour description systems,
and Use of colour.
What we see
Hue, saturation, and value describe what we see when we look at
pictures as well as the real world. Hue, saturation, and value are
sometimes manipulated in order to emphasize a particular ele-
ment relative to the other elements in a picture.
Hue
When we talk about the colour of an object we usually refer to the
hue of that object. Most people are familiar with hue through our
labelling of colours such as red, orange, yellow, green, blue, and
violet. Hue is colour. In colour description systems hues are usu-
ally placed in a band around a centre, in a “colour-circle.” (See
the subsection Colour description systems for further infor-
mation.) Different wavelengths of light reflected off an object are
responsible for the hues. All of the colours in the rainbow are
hues in the visible spectrum of light. It is possible for us to see
the difference between several million colours.
However, we can only distinguish about 10,000–20,000
hues (Hård and Sivik, 1981) different colours, and only about
seven colours in the same field of view. Yellow-green colour is in
the region of the eye’s greatest sensitivity. Sensitivity decreases
markedly toward the red and blue ends of the spectrum. Percep-
tion of colour is influenced by and dependent on contextual var-
iables such as lighting conditions and surrounding colours.
62
A black and white picture represents reality in a different
way than colour pictures. In black and white, all data about col-
our is translated into values of grey. Hue adds the “colour-dimen-
sion.” Hue may also act as a formal element in a composition and
direct the attention of the viewer. In information design, how-
ever, it is often enough to use white, black and one or two shades
of grey. A grey scale can usually serve the same function as a col-
our scale in a map. A colour scale, however, may be nicer and
more attractive. Value is more important to contrast than hue.
According to Dondis (1973) the broadest range of distinctly dif-
ferent grey tones in pigment is about thirty-five. Without light
upon it, the whitest of whites will not be seen at all. It is also hard
to distinguish between very dark grey and black.
A “high key” picture is composed with mainly light values,
and a “low key” picture has mainly dark values. Value may be
used to express emotions, form, space, and movements as well as
to give the illusion of light. Each colour has its own tonal value.
Our perception of one specific tone of grey, or any colour, can
change when it is placed on a tonal scale.
Saturation
Saturation is the apparent purity or lack of greyness of a colour.
A bright and pure colour is saturated and has no grey at all. A
colour with some grey is less saturated. A lot of grey gives an un-
saturated colour. A black and white picture is an example of total
un-saturation. The amount of saturation does not influence the
basic hue of a colour, and it is not related to the value. Saturation
steps run out in horizontal rows, from the vertical value-scale in
colour description systems. (Sometimes saturation is called
chroma or intensity. However, sometimes chroma is said to be
the combination of hue and saturation.)
Saturated colours are often considered to be aggressive,
bold, daring, vibrant, and they may grab our attention. Unsatu-
rated colours may be perceived as boring, dull, peaceful, restful,
soft, weak, and they may sometimes be depressing. Unsaturated
63
black and white pictures are often used to represent the past.
Highly saturated colours are frequently used to depict the future.
Boldly coloured objects seem closer to us than unsaturated col-
ours. Colour variations take the natural form of a triangle, a “col-
our-triangle.” At the top corner is white. Black is at the bottom
corner. At the third corner is the pure colour of hue. A mix of a
pure hue and white gives a tint. A mix of a pure hue and black
gives a shade. A mix of white and black gives grey. A mix of all
three colours gives a tone.
Value
Value (sometimes called tone) is the apparent lightness or dark-
ness in anything that is visible. It ranges from white to black. In
nature there are hundreds of steps in value. However, we can
only distinguish between a limited number of levels of value. Pic-
tures derive a simulated natural tone from pigment, paint, or ni-
trate of silver. There is an element of value in colour pictures, as
well as in black and white pictures.
There are hundreds of steps in value from white to black, but we
cannot always use more than a few.
In colour description systems values are usually placed on a
vertical scale, from white to black. It is not at all easy to distin-
guish between more than a maximum of ten shades of grey. In
printed materials grey is a combination of black ink and white
paper, measured as a percentage of full black. Bertin (1967) rec-
ommended the following steps in possible scales, with three to
nine steps, between white (W) and black (B):
64
W 49 B
W 30 73 B
W 20 50 82 B
W 16 38 66 86 B
W 14 31 51 74 88 B
W 11 25 42 61 78 89 B
W 10 21 35 52 68 81 90 B
W 9 19 31 45 60 74 84 91 B
Bertin (1967) recommended these steps in possible scales from
“complete white” (W=0%B) to “complete black” (B=100%B). All
these steps are expressed in “percentage of full black”.
Colour combinations
Looking at a picture printed in colour we experience a subtrac-
tive colour combination. The dyes, inks, and pigments function
like filters for the white light and present colour to the eye by re-
flection. The wavelengths of light are absorbed (subtracted) in
different ways. When printing on white paper, yellow and ma-
genta (a red-purple colour) produce red. Yellow and cyan (a blue-
green colour) create green. Magenta and cyan give blue. A mix of
all three primary colours will become black. The black ink gives
the picture a distinct sharpness and more solid dark elements.
Using the primary colours painters can mix paints of other hues.
65
This illustration shows a model for subtractive colour combina-
tions (left) and a model for additive colour combinations (right).
A picture tube or a cathode ray tube is the unit that produces
and shows the picture on a traditional TV-receiver, computer, or
terminal screen. The picture tube consists of an airless glass-
tube. Its rear end contains a device that which emits electronic
rays, while the front part forms the screen. When hit by the elec-
trons the back of the screen is illuminated. A picture is built by
steering the ray from differently coloured light sources over the
screen. In a picture tube the additive combinations of the pri-
mary colours red, green, and blue lights (RGB) can produce a
huge range of various colours. The additive colour combination
starts in dark adding light to produce different colours. The end
result is white. In this system, the secondary colours are yellow,
magenta and cyan.
Brightness constancy is our tendency to judge the bright-
ness of objects as constant, even though changes in illumination
make the objects appear brighter or darker.
Colour constancy is our tendency to judge surface colours as
the same despite changes in distance, viewing angle, and illumi-
nation.
The coloured pixels do not overlap on the screen. When
viewed from a distance, the light from the pixels diffuses to over-
lap on the retina in the eye. Projected additive light is used in
theatrical lighting, such as concerts and plays.
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This picture shows an example of colour constancy, our ten-
dency to judge colours as the same despite all the different
changes in distance, viewing angle, and illumination. (Here, I
have removed the license plates.)
Colour description systems
There are many theories about how perception of colours actu-
ally works. Colour can be described in aesthetical, physical, phys-
iological, psychological, and technical terms. Hue, value, and sat-
uration describe what we see when we look at pictures as well as
the real world. Intensity, purity and wavelength are physical di-
mensions. The relationship between brightness, hue, lightness
and saturation is very complicated. Colour is reflected in and
through light. There is nothing yellow in a banana. It’s all in how
it is perceived. For practical use in art and in industry several dif-
ferent systems providing numerical indexes for colour have been
developed.
The Natural Colour System
In 1892 the German physiologist Ewald Hering based his “natu-
ral system” on man’s natural perception of colour. Hering’s op-
ponent colour theory presupposes two pairs of chromatic colours
blocking each other, red/green and blue/yellow. This theory
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became the basis for the Natural Colour System (NCS), devel-
oped during the 1970s in the Swedish Colour Center Foundation
in Stockholm (Hård and Sivik, 1981).
From a perceptual point of view, we perceive six colours as
“pure.” Black and white are achromatic colours. Yellow, red,
blue, and green are pure chromatic colours. These six colours are
called elementary colours. All colours that are not pure elemen-
tary colours have a varying degree of resemblance to several ele-
mentary colours. Thus, every possible colour can be described
with a specific location in a three-dimensional model, a twin
cone, called the “NCS Colour Solid”.
The NCS Colour Solid with the six elementary colours. Yellow,
red, blue, and green are all located on the circumference of the
Colour Circle (here black). The Colour Triangle is any vertical
sector running through half of the NCS Colour Solid, such as
e.g. white–blue–black–white, and white–green–black–white.
The chromatic elementary colours yellow, red, blue, and
green are all located on the circumference of the Colour Circle.
One hundred steps, thus describing the hue of a colour, can di-
vide each quadrant.
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This figure illustrates a cut and opened circumference of the col-
our circle, here starting with red and ending with red.
The Colour Triangle is any vertical sector through half of the
NCS Colour Solid. It is used to describe the nuance of a colour,
i.e., its degree of resemblance to white, black, and the pure chro-
matic colour of the hue concerned (chromaticness).
There are many thousands of colour triangles. In this example
the figure illustrates the colour triangle ending in pure blue.
When we want to describe a colour using the colour triangle
and the colour circle, it is done in the following sequence: black-
ness, chromaticness, and hue. For example, a colour of 10
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percent blackness, 80 percent chromaticness, and with a hue of
Y70R will have the notation 1080-Y70R.
Here the NCS Colour Circle is combined with information on the
eye’s sensitivity. Our maximum sensitivity is between green and
yellow. Our minimum sensitivity is between red and blue.
Some other colour systems
The Munsell Colour System (MCS) was introduced in 1905 and
it has been modified several times. The system consists of fixed
arrays of samples that vary in hue, lightness (here called value),
and saturation (here called chroma). The value scale ranges from
white to black with nine steps of grey. Forty equal steps in a circle
represent hue. The value and the hue are related to each other by
a maximum of sixteen “saturation steps.”
There are many theories about how perception of colours ac-
tually works. In 1807, Thomas Young (1873–1829) proposed a
tri-chromatic colour vision system. In 1924, Young’s theory was
formalized by Herman von Helmholz (1821–1894), who pro-
posed hypothetical excitation curves for three kinds of cones in
the retina, sensitive for red, green, and blue.
In the Hue Lightness Saturation System (HLS), the hues are
arranged as circles on the outside of a double cone resembling
the NCS Colour Solid (Murch, 1983). Hue specifications start
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with blue at 0° and then follow the spectral order around the cir-
cle. Lightness and saturation are defined as percentages from 0
to 100. The HLS system is easy to use for colours on the surface
of the model. However, colours inside the model are difficult to
define. As in the Munsell- and NCS-systems, brightness creates
problems.
The Hue Value Saturation System (HVS) is a model that is
rather similar to the NCS-system but it utilizes another coding
(Samit, 1983). Here value is defined as the relative lightness.
White has full value and black has no value at all.
There are many other colour systems. Today printers who
use modern subtractive colour methods use magenta, yellow,
and cyan as subtractive primaries. Colour scientists often use the
additive primaries, red, green and blue.
In visual displays the colour stimuli are specified by Red,
Green, Blue (RGB) values as discussed above. People who are
specially trained can use the RGB proportions as a colour de-
scription system. However, this is not possible for people in gen-
eral. In web design colours are defiend with a six-digit
hexadecimal number or triplet, a hex value/hex triplet. Colours
can be specified in the format #RRGGBB, where RR, GG, and BB
are the hexadecimal values for red, green and blue values of the
colour. The values varies from zero to maximum 255 for each
component.
Use of colour
The symbolic meanings of colour vary from culture to culture.
European cultures put on black to mourn a death, while Asians
wear white for the same occasion. In Western European cultures
blue is a symbol for authority or calmness. Yet, in Japanese cul-
ture it connotes villainy, and in Arabic cultures blue symbolizes
virtue and truth. Thus, we should be very careful when using col-
our in international information materials, especially when the
context may suggest religious or social interpretations. It is often
a good idea to design visuals that work well in black and white,
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and then add colour to make them work even better. The main
function of colour is to differentiate between events, places, sub-
jects, states, times, etc. A common convention in moving pictures
is to use black and white to represent the past and colour to rep-
resent the present (Block, 2008). Colour is one of the essential
devices for telling a story through visual imagery (Brown, 2016).
Affective use of colour
Colour enhances the attention and perception of a visual mes-
sage. If people like the contents in a picture, they like them even
more when the visual is presented in colour. From many experi-
ments, it is clear that people prefer colour in visuals. Advertising
is known to be much more effective when visuals are in colour
than in black and white. Tests have indicated that viewers feel
that they have a better understanding when television images are
displayed in colour, although the use of black and white some-
times would be sufficient.
However, an improper use of colour can produce negative
results: it can be distracting, fatiguing, and upsetting. Yellow, or-
ange, and red hues are perceived as warm and active. Red evokes
feelings of strong emotions. Violet, blue, and blue-green are per-
ceived as cool and passive hues. Blue is often used to represent
truth and honesty. White is often associated with innocence and
pureness, and black often represents evil and darkness.
According to Gatto, Porter, and Selleck (2011, p. 72) “colour
appeals directly to our senses and emotions.” Colour is consid-
ered to be an important element that decides the mood of design
(Lohr, 2010). For example, pastel colours convey the feelings of
quietness and peacefulness. In addition, using similar colours
produces the sense of harmony while using contrasting colours
produces the sense of power. Furthermore, cool colours seem to
recede while warm colours seem to come forward (Gatto, Porter,
and Selleck, 2011).
The many possibilities of manipulating colour in the process
of post-production are almost unlimited. In the digital age colour
72
has become another independent variable that can be freely
changed.
Colour blindness
Colour blindness, or better still “anomalies of colour vision”, is a
condition in which certain colour distinctions cannot be made.
This is more commonly observed among men than among
women, with estimates ranging as high as 10% of the male popu-
lation. Only 1% of the female population has anomalous colour
vision. Failure to distinguish between red and green is most com-
mon. Both hues are perceived as grey.
Common colours in graphic symbols are pure yellow, red,
blue, green, white and black, or combinations of these. Unfortu-
nately, red and green are often used as discriminating colours in
symbols and in warning signs. Since many colour-blind people
perceive red and green as grey, colour can only be used to code
the information redundantly. Colour may be combined with
shape, and position, or with both, which is often seen in traffic
signs.
Cognitive use of colour
For some learners and for some educational objectives, colour
improves the achievement of the learners. However, in some
cases the added cost of colour will not be justified. Colour is im-
portant in a visual when it carries information that is vital to the
contents in the visual. It is, for example, easier to learn to distin-
guish between various species of birds or butterflies when colour
illustrations are used, instead of black-and-white illustrations.
Highlighted information tends to be better remembered.
Colours can easily be used for associating, defining, high-
lighting, and separating information. In line drawings or in
black-and-white photos, for example, the addition of one single
colour may be very efficient. To avoid confusion and misunder-
standing, it is important that colour be used consistently. Colour
is capable of enhancing communication and adding clarity and
impact to a message. In spite of the large quantity of research,
73
colour perception still only seems to be partially understood. It
could be concluded that:
• People might see colours in the same way. However, no two
persons experience colour in precisely the same way.
• The human reactions to colour stimuli cannot be standard-
ised.
• Depending on sex, age, profession, and culture, there are dif-
ferent subjective reactions to colour.
• There are likes and dislikes of colour, based on general as well
as personal associations.
• Colours can be associated with temperature and emotions.
Colour coding
Colours are often used for colour coding, for example, of objects
and in documents. Colour coding is also used in different signs
and symbols. This may improve attention, learner motivation,
and memory. However, the number of colour codes should be
limited and always explained. When the number of colour coded
items increases, the value of colour as a cue for selecting im-
portant information decreases.
A colour-coding process may enable learners to retain criti-
cal information and disregard redundant and irrelevant infor-
mation. An effective and systematic colour code, with a maxi-
mum of four to six colours, in a learning material assists the
learner in organising and categorising stimuli into meaningful
patterns. To avoid confusion and misunderstanding, it is im-
portant that colour be used consistently. Inconsistent and im-
proper use of colour can be distracting, fatiguing, and upsetting,
and it can actually produce negative results and reduce learning.
It should also be remembered that some people are red-green
colour blind and they perceive these hues as grey.
Colour contrasts
In 1912 Kandinsky published his provocative thoughts on colour
theory, and the nature of art and beauty (1912/1977). He studied
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the harmony of colours and found that colours evoke a double
effect (23-24): (a) A purely physical impression, and (b) a psy-
chic effect in which colour produce a spiritual vibration, and may
touch the soul of the beholder.
Kandinsky discussed four main colour contrasts in paint-
ings: (a) Yellow-blue, (b) white-black, (c) red-green, and (d) or-
ange-purple. It seems that a warm yellow surface moves closer to
us, while a cold blue surface seems to move away. Green, which
is a mixture of blue and yellow paints, yields calm and immobil-
ity. The white-black contrast is static. Red is an agitated and
warm colour. Red and black becomes brown, a hard colour. Red
and yellow becomes orange. Red and blue becomes purple. White
is clarity, and a deep silence. Black is eternal silence without
hope, nothingness, and obscurity. Grey has no active force and
corresponds to immobility without hope.
Colour preferences
Generally speaking people prefer surface colour hues according
to this ranking: 1) Blue, 2) Red, 3) Green, 4) Violet, 5) Orange,
and 6) Yellow. However, blue, red, and green do not improve our
possibility of reading the message accurately. Children prefer
colour hues that are light, distinct, and shining better than col-
ours that are dark and gloomy. Colour intensity should be strong
and colour contrast should be clear. People in different cultures
and in different socio-economic groups use colours in different
ways and with different meanings. In cultures in Africa, Central
and South America, and Indonesia, bright colours and high con-
trast are common in illustrations.
Decorative use of colour
There are many situations where colours can be used for decora-
tion. However, a decorative use of colour should never be mixed
with other uses of colour. It must always be clear, and easy to
understand when colour is used for decoration and when the use
is meant to have some cognitive importance. This is also true for
the general structure of visuals. Most visuals are too complicated
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and would communicate better if designers valued simplicity
over decoration. This is especially true in electronic documenta-
tion that shall be read on a computer screen.
Contrast
In nature, as well as in art, contrast is of major importance for
our perception of a message. The contrast is the difference be-
tween the brightest and the dimmest parts of a picture or of a
text. The contrast should be clear and differentiate image ele-
ments from one another. This is regardless of the colour chosen,
and regardless of any colour-contrast effects. Visual acuity, our
ability to discriminate small objects, peaks at about age 22, and
then a steady decline starts. Unfortunately, this decline is not
possible to correct with eyeglasses. At about age 40 the tissues of
the eyes get stiffer. This condition is called presbyopia or “old
eyes.” It makes it harder for us to shift the distance of our focus.
Thus, it is harder to change between reading a text on a screen,
and reading a text printed on paper.
Our perception of one tone of grey (five circles) change when it
is placed on a continuous tonal scale, here from white to black.
Throughout our lives the lenses in our eyes become less and
less transparent. Because of this constantly increasing opacity we
require more contrast between a message and its background to
see any fine details in images and to read text. The biggest offense
to less than perfect eyes is a lack of contrast between message and
background.
Coloured text on a coloured background is a common exam-
ple. Different hues may have the same value, and as a result al-
most no contrast. It is far too common that illustrations in
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textbooks and video programs do not have good contrast. In-
stead, it is quite often a more or less even shade of grey or chro-
matic colours.
Another common problem is the use of too small type. Text
must be large enough. Also, symbols are often too small. The dif-
ference in resolution in different media is very important. A type-
setter can produce 10,000, a laser printer 140, and a high-reso-
lution computer monitor only ten dots per square millimetre. For
people to be able to recognize the colour of an object it should be
at least 1.5 millimetres for marks on a paper and six pixels on a
computer screen. Thus, graphics designed for paper must usually
be simplified for display on computer screens. In the comparison
of the darkness of tones on a graphic display, differences in tones
will be overestimated. It is known that high contrast between ob-
jects attracts attention, and children prefer light visuals as com-
pared to dark visuals.
Texture
Texture is the visual equivalent of the sense of touch and the feel
of an object’s surface. From our experience, we know that a
sweater is “soft,” a steel tube is “hard,” and that a piece of broken
glass has a “sharp” edge when we touch it gently with our finger-
tips. We can see minute variations in colour and structure of a
surface. In our daily lives, we have great use of our perception
and understanding of texture when we look at various objects in
our surroundings.
Optical texture serves as a stand-in for the qualities of actu-
ally touching and sensing the real objects. Texture makes objects
appear to be smooth or rough, soft or hard, heavy or light, sharp
or flat according to our personal experience of these objects. We
can avoid touching a hot stove. We can be very careful when we
have to pick up sharp pieces of broken glass and sharp-pointed
and sharp-edged pieces of metal.
Optical texture also works in visuals. In a picture, a sweater
and the skin of a baby looks “soft,” a steel tube looks “hard,” and
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a piece of broken glass looks sharp. In a photograph, we may rec-
ognize and “sense” the hard-bronze surface in a sculpture and the
soft and warm yarn in a textile. The bronze surface may be per-
ceived as warm, or as cold depending on the content, the lighting
and the context in the picture. Texture is very important in the
visual arts.
In a photograph we can experience the surface of paper, plas-
tics, stone, wood, and many other materials, and remember the
feeling from the time when we have touched it. To be able to do
this the lighting in the picture and the shadows are very im-
portant. Lack of detail communicates a smooth texture. In a
painting, clear and distinct brush strokes contribute to an im-
pression of three-dimensional texture. Texture adds realism in a
picture. It also adds an emotional and psychological effect. Many
persons react in a positive way to soft and smooth objects, and
they find sharp and rough objects repulsive.
Light
Light is essential to the appreciation of three-dimensional im-
ages like sculptures. Whether the light is coming from the left or
from the right, the top or the bottom, makes a crucial difference
in the appearance of the forms. Soft light helps us appreciate sub-
tle undulations. Strong light accentuates details on the surface. A
shadow is an area where there is absence of light.
The word photography has its origin in Greek and means
“writing with light.” Drawers as well as painters and photogra-
phers make use of various lighting conditions, light, shadows,
and darkness to create perceptions of volume in two-dimensional
pictures. A person or an object depicted in hard or soft light will
be perceived differently. The physicist defines light as visible ra-
diant energy. Actually, light is invisible. We can see it only at its
source and when reflected. Light has outer as well as inner orien-
tation functions.
This main section includes the following sections: Outer ori-
entation functions, and Inner orientation functions.
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Outer orientation functions
Light will articulate our outer orientation with respect to space,
texture, and time. Without shadows, it may be hard to make out
the basic contour of an object. Shadows define space. The at-
tached shadow is on the actual object. It helps to reveal the basic
form and dimensions of that object. The cast shadow is fre-
quently observed as being independent of the object that caused
it. Depending on the angle of the light source, the cast shadow
may reveal the basic shape and location of the object that caused
it. The surface appears to be curved when the light falls off grad-
ually. A highly directional (hard) light produces fast fall-off.
Thus, a curved surface is emphasised.
Here the rather pale light from the rising sun gives very distinct
cast shadows on the ground.
A highly diffused and non-directional (soft) light produces
slow fall-out. Prominent cast shadows caused by hard light from
a low angle emphasize texture. Soft light, on the other hand, de-
emphasizes texture. Thus, both hard and soft light may be used
successfully for spatial and tactile orientation, for example, in
79
portrait photography. In daylight the background is usually
bright. The cast shadows are very pronounced and the fall-off is
fast. In a night-time scene, the background is dark. The lighting
from various light sources is highly selective. Shadows are prom-
inent. The human eye is attracted to bright areas. This can be
used for emphasis and directing attention in a visual. Bright ar-
eas tend to be perceived in front of other picture elements, while
dark areas tend to be perceived as receding.
Inner orientation functions
As well as light can articulate space, texture, and time; it can also
articulate inner orientation functions. In motion picture and TV
production, light, especially combined with music and sound ef-
fects, can evoke a great variety of specific feelings and emotions
within us. Minor position changes of principal light sources may
have drastic effects on our perception of mood and atmosphere.
For example, a face lighted from below may appear brutal, dra-
matic, ghostly, mysterious, and unusual.
Composition
Composition is discussed here mainly within the individual pic-
ture, and not the composition of a page or a screen. We need to
organize picture elements within an individual picture and find a
balance in accordance with aesthetic principles. This main sec-
tion includes the following sections: Organization, Balance in
pictures, Centres of interest, and Direction.
Organization
Usually a visual shall deal with only one concept, and only pro-
vide the information that is necessary for the audience to under-
stand the content. The elements in a visual may be arranged in a
pattern that is clear and easy for the reader to comprehend. Or-
ganization provides a pattern that facilitates learning. By organ-
izing the graphic elements, it is possible to direct the eye move-
ments within the picture. Perceptually, we group things on the
80
basis of similarity and distinguish between things on the basis of
disparity. Certain stimuli, such as contour lines, unusual colours,
or graphical symbols, are accentuated in perception while others,
such as uniform areas, are not. Background colours, shades,
frames, and typography, can be used to achieve unity. In this way,
the picture elements are viewed as a whole, as a unit. Horizontal
and vertical lines are easily compared.
Organizing a message can make perception much easier and
learning more efficient. A visual should have a moderate degree
of complexity. Complexity without order produces confusion,
and order without complexity produces boredom. Differences in
texture and grain may help organizing information.
To serve their function, schematic pictures must be well ar-
ranged. Since they cannot contain too many picture elements, it
is better to divide the information into several different pictures
than to allow one schematic picture to be overloaded. We should
not use a schematic picture when a simple list will do. There must
be sufficient distance between different elements in a picture, at
least a few millimetres.
I it may be necessary to show several (= an undefined num-
ber) similar picture elements in one schematic picture, for exam-
ple, several documents, several processes or several samples of
particular hardware or software. To save space, the picture ele-
ments can be partly superimposed on one another, but it is wise
to limit these elements to two or three at the most, to keep the
schematic picture from being overloaded. To aid comprehension,
a pair of picture elements that are connected to each other can
constitute a symbol that means “several documents,” for exam-
ple, or “several processes.”
To avoid misunderstandings, we should not use shadows be-
hind picture elements to provide aesthetic spice or a false third
dimension. If necessary, the number of picture elements can be
shown as a digit on the actual symbol. The idea of “several” pic-
ture elements can also be expressed simply by giving the symbol
a plural name.
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We can place picture elements at different levels in a sche-
matic picture. If we do however, it must be done in a logical, well-
planned and consistent way to limit the risk of misinterpretation.
We should avoid three-dimensional schematic pictures as they
are often misunderstood.
Balance in pictures
In nature balance is normal. A visual should usually display the
best possible balance. Elements of the visual should fit together
in an aesthetic and harmonious relationship in a manner that is
interesting but not distracting. Man has an intuitive sense of bal-
ance. When a single element is too large or too small, too light or
too dark, too prominent or too indistinct, the entire picture will
suffer from this imbalance.
Imbalance creates an uncomfortable feeling in the reader
and should often be avoided. Imbalance, however, can be used to
attract attention within a picture or within a material. Unex-
pected, irregular, and unstable design will attract attention. As
soon as instability is introduced in a picture the result is a pro-
vocative visual expression. The eye will struggle in order to ana-
lyse the relationships and the balance within the picture.
Balance can be formal with total symmetry or it can be in-
formal. Formal balance is felt to be static and harmonious. In-
formal balance contributes to a feeling of dynamism. However,
the mind needs stimulation and surprise. Contrast and imbal-
ance can dramatize an image and attract attention. Several artists
use a visual strategy, such as combinations of dark and bright,
large and small, round and square, to sharpen meaning.
Centres of interest
Avoid dividing a visual in halves. The visual should only have a
few centres of interest, preferably only one at or near its optical
centre just above and to the left of its geometric centre or other-
wise in the upper third of the visual. In the US, viewers tend to
begin looking at a visual from the left side, particularly the upper
82
left portion (41%). The centre of interest should be immediately
apparent (McDougall and Hampton, 1990). Thus, the visual has
unity. The most important elements of the visual may be empha-
sized to enhance perception. We may use lines of direction to
guide attention to a centre of interest.
Don’t centre the centre of interest. According to the “rule of
thirds” the centre of interest may be selected at any one of the
four points where two equidistant vertical and two horizontal
lines divide a picture in a total of nine parts. Don’t centre a hori-
zon. Place the horizon in the upper or lower third of the picture.
Young children may choose to pay attention either to the whole
picture or to specific parts of it. For children until about nine
years of age it might be difficult to switch attention between a
part and the whole.
Direction
Studies of eye movements and fixations have shown that various
people look at the same picture in different ways. As previously
noted the importance of eye movements can be summarized in
five points:
• Only certain image elements attract our interest.
• The pattern for eye movements and fixations depends on
what we wish to see or what we are told to see in a picture.
• Informative parts of a picture attract more fixations than less
informative parts.
• Different kinds of pictures give rise to different kinds of fixa-
tions and intelligence and visual learning.
• There is a positive correlation between the number of fixa-
tions and intelligence and visual learning.
By organizing the graphic elements, it is possible to direct the eye
movements within the picture. Lines, shape, scale, perspective,
position and orientation of objects are all essential parts in
providing direction in a picture. Using lines with arrowheads is
probably the easiest and most powerful way to show direction.
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The information should be organized in such a way that the
most important information is most prominent. We need to cre-
ate visual focal points in order to highlight importance and to
maintain interest in the visual. Diagonals are the most powerful
of all directions in a visual. They may suggest a strong feeling of
imbalance and motion.
A left to right incline is associated with growth and prosper-
ity, “uphill.” Here the lower left part indicate inferiority, and the
upper right indicate superiority and dominance. A left to right
decline on the other hand is perceived as a decline, “downhill.”
Here the upper left part indicates superiority and dominance,
and the lower right indicate inferiority. This may be very im-
portant in some schematic pictures. Also, curved directions have
elements of instability. McDougall and Hampton (1990, p. 34)
pointed out that subjects moving into a picture appear more dy-
namic than those moving out of it.
Pictorial perspectives
With two eyes, we naturally see in three dimensions. The illusion
of depth and dimension is created when our brains interpret the
slightly different views from our two eyes. We get a spatial aware-
ness of our physical environment. We also have a tactile aware-
ness in three dimensions of smaller objects. We have to distin-
guish between an optical reality and a perceptual reality.
Optical reality is governed by geometry and is only visual.
However, perceptual reality is governed by object constancy and
combines what we already know about the subject with what we
can feel, hear, see, smell, etc. Most pictorial perspectives are spa-
tial perspectives. Psychological perspectives are visualisations
of psychological and subjective concepts and values.
Considering the manner in which spatial perspectives are
built up, they can be divided into three groups: line-based posi-
tional perspectives, area-based positional perspectives, and
other positional perspectives. Of course, painters often use sev-
eral different types of perspectives to enhance the effect of depth
84
in a single picture. Line perspectives, aerial perspectives, colour
perspectives, and tonal perspectives may well be used to interact
with each other and to create lifelike pictures. For schematic pic-
tures that are meant to show three-dimensionality, it is usually
more appropriate to only use one of the line-based positional
perspectives.
This main section includes the following sections: Line-
based positional perspectives, Area-based positional perspec-
tives, Other positional perspectives, and Psychological perspec-
tives.
Line-based positional perspectives
In a line perspective or linear perspective objects are conceived
as being placed behind a picture plane onto which straight beams
of light (so-called straight lines) are projected. All line perspec-
tives are based on the idea that an object appears to grow larger
in size as the distance between it and the observer decreases and
get smaller as the distance increases. A view along a road with
identical lampposts or identical trees will produce the familiar
convergence of lines. The lampposts and trees appear to be suc-
cessively smaller. This phenomenon is sometimes called dimin-
ishing perspective.
In the western world the position in a picture of a known ob-
ject, like a car or an ordinary person, with a known size will give
us a depth cue. Regardless of distance there is constancy in the
perception of the size of known objects (size constancy). The per-
ception of distance is related to the perceived size, and the per-
ception of size is reciprocally related to the perceived distance.
In visuals that are used for information and instruction we
need to show scale and contrast. It is usually a good idea to in-
clude a person or a familiar object to supply the scale for judging
the size of unfamiliar objects. The perceived size of an object is
relative to the size of other objects. Thus, the size of an unfamiliar
object is perceived as relative to the size of familiar objects.
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Distant objects appear to be smaller than objects that are close.
When a car is approaching it seems to grow larger. However,
children soon learn that the car will maintain its size. Regard-
less of distance there is constancy in the perception of the size of
known objects. This is called size constancy.
Central perspective
A linear perspective uses the principle that parallel lines seem to
converge or meet at a distant point. In a view of long straight
roads and railway tracks the sides appear to meet at a vanishing
point on the horizon even though they are parallel in reality. An
artist represents linear perspective by moving all lines on the
canvas toward a vanishing point on the geometrical horizon line.
(The true horizon is the line dividing the sky from the ground. It
is lower than the geometrical horizon since the surface of the
Earth is curved. We can’t see this difference when we are stand-
ing on the ground level. However, a person standing on a moun-
tain can see further away.) The eye level of the observer deter-
mines the location of the geometrical horizon line. A central per-
spective is the graphic equivalent of optical reality.
One vanishing point
If all lines vanish in a single point, the picture is in a one-point
perspective. This is also called central perspective and Renais-
sance perspective. One vanishing point is typically used in pic-
tures of buildings directly facing the viewer, of hallways, railway
tracks, and roads.
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The central perspective is a rather recent perceptual acquisi-
tion, developed in the early Renaissance by artists who learned
to see form and space in a new way. The laws of perspective was
known already by the Greeks and the Romans but this knowledge
had been lost. Then the Italian architect Filippo Brunelleschi
(1377–1446) discovered the mathematical laws of perspective
and he demonstrated the geometrical method of perspective
about 1413. Brunelleschi worked out some of the fundamental
principles, including the concept of the vanishing point.
Railway tracks appear to meet at a distant point on the hori-
zon, the vanishing point. But luckily for us, they never meet.
The Italian multi-talented architect, classical scholar and ex-
plorer of the fine arts Leon Battista Alberti (1404–1472) regarded
mathematics as the common ground of art and sciences. At this
time, pictorial art was regarded as a science that could be applied
to explore the laws of nature. In his book Della Pittura (De Pic-
tura, On Painting) 1435/1436, Alberti relied on classical optics in
determining perspective as a geometric instrument of artistic
87
and architectural representations. He described Brunelleschi’s
mathematical construct of the central perspective (Toman, 1999,
p. 448). Alberti showed how the rays of light, passing from the
viewer's eye to the landscape, would strike the picture plane (the
painting). He was able to calculate the apparent height of a dis-
tant object using two similar triangles. The Italian painter Piero
Della Francesca (1415–1492) further described central perspec-
tive for solid objects in any area of the picture plane. He used il-
lustrated figures to explain the mathematical concepts.
The first textbook to explain the basics of perspective was
published as early as 1492. Before then, several manuscripts had
been written. Some woodcuts by Albrecht Dürer (1471–1528)
demonstrate a drawing table called a “Leonardo box,” named af-
ter Leonardo da Vinci (1452–1519). This was a perspective tool
using a frame with a square grid to achieve an accurate linear
perspective of an object when the artist worked on a surface with
a similar grid. Using this method, the artist could be sure that all
the lines drawn accurately represented the objects in correct cen-
tral perspective positions. Art was meant to represent in exact
detail what could be viewed by a one-eyed person standing at a
singular location at an exact moment in time. Science searched
for theories that reduced human experience to its most basic
forms, allowing for an abstraction into mathematical language.
Soon most artists in Florence and in Italy used central per-
spective in their paintings. Gradually the Italian techniques be-
came part of the training of artists across Europe. Some painters
accomplished such accuracy that their works stand comparison
with projection drawings, or even with photographs. In early Re-
naissance paintings, the floor is often made out of marble
squares. These squares form a perfect linear perspective in the
pictures. Some artists used to draw accurate landscapes using a
large camera obscura. The artists actually worked inside the box,
where they traced the upside-down image on a thin sheet of pa-
per on the inner wall.
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Much later, light-sensitive material became the basis for
photography. Leonardo da Vinci’s used central linear perspective
to express the social importance of Christ in The Last Supper,
one of most famous paintings. All of the diagonal lines in the pic-
ture converge on the face of Christ, at the vanishing point in the
middle of the painting. However, Leonardo da Vinci was not sat-
isfied with the one-point perspective and he experimented with
more views (McLean, 1999, p. 106). The main disadvantage with
central perspective is the exact rendering of an object from one
specific situation with respect to conditions like distance, eye
level, lighting, place and time. The object looks different when it
is seen from all other places and in all other moments in time.
Two and three vanishing points
Lines that vanish in two directions to two different vanishing
points produce a two-point perspective. This is also called angu-
lar perspective and oblique perspective. All linear perspectives
have exact formulas with many and complicated geometrical and
mathematical rules. The two-point perspective can be used to
draw all objects.
This cube is drawn in a two-point perspective, with two vanish-
ing points (Vp1 and Vp2) on the geometrical horizon line.
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Here the first cube is drawn in a correct two-point perspective.
The other four cubes contain common errors in their perspec-
tives. The second cube is too wide. The third cube is too tall. The
fourth cube is out of convergence, and the fifth cube is out of
proportion.
The three-point perspective is usually used in pictures of
buildings seen from above or seen from below. In addition to the
two regular vanishing points, there is also one below the ground
or up in the sky. Each vanishing point corresponds with one of
the three axes of the scene.
Dondis (1973) pointed out that perspective dominates in
photography. Any standard camera with ordinary lenses pro-
vides us with linear perspective pictures. The camera lens has
some of the perspectives of the eye, and simulation of dimension
is one of its prime abilities. Some photographers use linear per-
spective and its vanishing point or points to create dynamic com-
positions. By association, diagonal lines of all kinds contain a
suggestion of depth.
The field of the camera lens is changeable. What we can see
and record is determined by the focal length of the lens. The nor-
mal lens has nowhere near the range of field of the human eye,
but from a depth point of view, what the lens records is close to
the perspective of the eye. Telephoto and wide-angle lenses can
distort the representation of reality. A telephoto lens will narrow,
and a wide-angle lens will broaden the field. Regardless of the
lens used during photography, the actual light sensitive film in
the camera is the same. Thus, only a normal lens provides a
“good” representation of an object on the film. At the same dis-
tance, all other lenses give some distortions.
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We can distinguish between five different “level perspec-
tives.” Starting from the highest level these are called bird's-eye
perspective, military perspective, gentleman's perspective, eye-
level perspective, and worm's-eye perspective.
Bird’s-eye perspective
In the bird’s-eye perspective, or bird’s-eye view, an object is
viewed from a high position. We may be looking down from a
vantage point in a high building, on a mountain, or in an air-
plane. Bird’s eye views have existed since classical times. In art,
film, photography and video a person seen from this perspective
look small, unimportant, and weak. Too high view of a person
shows little convergence. The perspective is often used for blue-
prints, floor plans and maps.
Here we can see that two persons are standing down in the
lobby of a hotel. This is a bird’s-eye perspective.
Some satellite photos and computer programs offer the
viewer the opportunity to "fly over" and observe parts of cities
and landscapes. This perspective is often used when there are
three vanishing points, one below the ground or in the sky, one
on the left, and one on the right. Sometimes the terms aerial
view and aerial viewpoint are used for bird’s-eye perspectives.
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The term aerial view can refer to any view from a great height,
even at a wide angle.
Eye-level perspective
Objects are usually viewed straight from the front and at the
same level as the viewer. This “normal” way of viewing could be
said to represent the eye-level perspective or normal perspec-
tive. Compared with a normal camera lens, the narrow field from
the telephoto lens makes the representation of an object broader
on the film. The wide field provided by a wide-angle lens makes
the representation of an object narrow on the film. Wide-angle
lenses have a propensity to enhance linear perspective, while tel-
ephoto lenses tend to flatten the perspective. Objects are usually
viewed straight from the front and at the same level as the viewer.
This “normal picture angle” and the normal way of viewing is the
least obtrusive angle.
The gentleman’s perspective is higher than the eye-level per-
spective but lower than the military perspective. Several histor-
ical paintings of troops and battles show a military perspective.
Higher than the eye-level perspective, this was perfect to see the
different groups of soldiers on the battlefield. In computer and
video games, an overhead view of a situation places the vantage
point only a few feet above human height. The bird’s-eye per-
spective is the opposite of a worm’s-eye perspective.
Worm’s-eye perspective
In the worm’s-eye perspective, worm’s-eye view, or frog per-
spective, an object is viewed from below (at an oblique angle).
This perspective is often used in propaganda. The viewer has to
look up to something. In art, film, photography, and video a per-
son seen from this perspective look big, important, mighty, pow-
erful, strong and tall. However, a too low view of a person fails to
read clearly. This perspective is often used when there are three
vanishing points, one on top, one on the left, and one on the right.
This is the opposite of a bird’s-eye perspective.
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Time perspective
A “time-line” is a simple one-dimensional scale with markings
for important events. This is often used in graphics and schema-
tic pictures to visualize the relationships between different his-
torical events. Using a time-line makes it easier for the viewer to
see the time perspective.
Forced perspective
A forced perspective is a form of optical illusion. Forced perspec-
tive is used in architecture, film, photography and video to ma-
nipulate human visual perception. It is used to make an object
appear to be larger or smaller, to be closer or farther away than
it actually is. Producers use scaled objects and manipulate the
correlation between them, the camera or viewer, and the vantage
point. In the picture, a large distant building or a group of dino-
saurs in the background may in fact only be very small miniature
models that are hold close to the camera. Then the building and
the dinosaurs may look monstrously tall in the final pictures.
Forced perspective was often used in movie production in
the 1950s and 1960s. These productions required complicated
lighting since the intensity of light rapidly decreases when the
distance to the objects increase. The foreground object as well as
the background must be sharp. Modern digital processes may of-
ten be employed today.
Forced perspective is often used in architecture of entertain-
ment theme parks, like Disneyland. Here different buildings and
other structures often need to seem larger than they are in reality.
Curvilinear perspectives
The four-point perspective, or infinite-point perspective, uses
curving perspective lines to approximate the image on the curved
retina in the bottom of the human eye. It is the curvilinear variant
of a two-point perspective. A four-point perspective image be-
comes a panorama that can go to a 360-degree view and beyond.
When also a vertical line is used as a horizon line it is possible to
93
see both a worm’s eye view and a bird’s eye view at the same time
(Wikipedia, 2013).
The five-point perspective, or fisheye perspective has four
vanishing points placed in a circle and one in the centre. This is
the curvilinear equivalent of a one-point perspective. Fisheye
lenses are ultra-wide-angle lenses that produce strong visual dis-
tortions. These lenses are used to create wide panoramic or hem-
ispherical images.
Parallel perspective
When the distance is endless parallel lines of an object are also
parallel in the image. This is called parallel perspective. In the
western cultural sphere, we are used to seeing visuals with one-
and two-point perspectives. Perspective drawing offers possibil-
ities to reproduce depth, but it is always limited to showing ob-
jects from just one certain point. In several cultures, it is better
to use orthographic views. An orthographic drawing does not
show an object in perspective, but in “scale.” Objects are repre-
sented as they are remembered. Mechanical orthographic draw-
ings show proportions accurately with a parallel projection. Par-
allel lines of an object are parallel in the picture too. This results
in three-dimensional pictures with distorted diagonals.
When orthographic drawing is traditional in a culture, it is
usually drawn freehand, and accuracy is not so important. In
some places, only man-made objects and buildings can be drawn
orthographically; natural things, including people may not be
drawn this way. Zimmer and Zimmer (1978) called orthographic
views or orthographic projections non-perspective, but they are
sometimes called parallel perspectives resulting in para-line
pictures. Brouwer (1995) noted that the concept of perspective in
a picture is usually not understood in rural Africa.
94
In the western cultural sphere, we are used to seeing visuals
with central perspective, as in the drawing of a table (left). In
some cultures, it is better to use orthographic views that do not
show an object in perspective. The mechanical orthographic
drawing of a table (middle) shows proportions exactly. A free-
hand orthographic drawing, to the right, is not so exact. In par-
allel perspective (right) parallel lines of an object are parallel in
the picture too (adopted from Zimmer and Zimmer, 1978; pages
58–59).
In parallel perspective, a plan shows a view locking down on
an object, a section is an image that describes the object as if it is
sliced, and an elevation is a view looking from any angle describ-
ing relationships of verticals and horizontals. Parallel perspective
combined with a viewpoint from above is common in traditional
Chinese painting. Often foliage is used to crop the parallel lines
before they extend far enough to cause a building to appear
warped. Even in early Japanese art, the roofs of buildings were
lifted in order to tell us what is happening inside them.
Reversed line perspective
In a reversed line perspective, the foreground seems to be
smaller than the background. The straight lines converge in the
direction of the viewer. This perspective is frequent in Japanese
and Chinese art, which seeks to draw the viewer into the picture
to take an active part in the events depicted. In early Asian art,
there are no shadows. It is conceivable that a reversed line per-
spective can be either a reversed parallel perspective or a re-
versed central perspective.
95
Area-based positional perspectives
As noted earlier central perspective has one or more vanishing
points. A perspective with no vanishing points, a zero-point per-
spective, occurs when the viewer is observing a non-rectilinear
scene like a natural scene. In painting and photography, the
depth of a picture can be visualised in several ways and not only
through a linear perspective.
In accordance with Freeman (1988) a heightened sense of
depth through strong perspective tends to improve the realism in
a photograph. It makes more of the representational qualities of
the subject, and less of the graphic structure. Photographs often
have well-defined foregrounds and backgrounds, and parts in be-
tween. Depth of field is how much of a picture from near to far is
in sharp focus. In photography, the depth of field is influenced by
the distance to the object, the focal length and by the camera ap-
erture. The depth of field can vary from several meters to a few
decimetres. By making the foreground sharp and the background
blurred, the interest of the viewer is directed to the foreground,
and vice versa.
The group area-based positional perspectives include aerial
perspective, colour perspective, tonal perspective, overlapping
perspective, and shadow perspective.
Aerial perspective
In a picture of an open landscape, without a natural and obvious
line perspective, aerial and colour perspectives create an im-
pression of depth. The air and atmosphere are never absolutely
clear and clean but rather filled with a grey or greyish blue haze,
moisture, and dust. This acts like a filter and makes distant ob-
jects seem obscure and wrapped in mist and they may be partly
hidden. Distant objects are lighter than nearer objects. Their con-
trasts with the backgrounds are reduced.
Colour saturation is reduced and shift towards the back-
ground colour, usually blue. At sunrise or sunset distant colours
may shift towards red. When the distance to an object increases,
96
the contrast decreases. As a consequence, objects viewed from a
long distance are indistinct and pale. This phenomenon is called
aerial perspective, or atmospheric perspective.
This picture demonstrates combined aerial and colour per-
spectives, late in the afternoon. Colour saturation is reduced
and shift towards the back-ground colour.
The painter Jan van Eyck is one of the most significant rep-
resentatives of Northern Renaissance art. The brothers Van Eyck
painted the large Ghent Altarpiece, now almost 600-year-old.
This polyptych with 26 paintings is an impressive rendering of
Catholic mysticism. Jan van Eyck used new techniques of han-
dling both oil paint and transparent glazes. The depiction of the
churches, landscape and mountains in the background of the
large painting Adoration of the Mystic Lamb contains the first
known example of aerial perspective in art. Many artists in the
Netherlands followed Jan van Eyck and used aerial perspective
in their own paintings. Later Leonardo da Vinci used aerial per-
spective in many of his paintings such as the Mona Lisa.
97
An artist draws objects nearest to the observer in sharp,
heavy lines and bright colours. Sections of a painting that are in-
tentionally made indistinct, without sharp outlines and in neu-
tral colours, will appear as being located far away. They fade away
into the distance. In photography, the effect of aerial perspective
appears strongly in backlighting.
Colour perspective
In a colour perspective colours and hues gradually change from
being clear in the picture’s foreground into being blurred in its
background. Warm-coloured objects appear closer to the viewer
than cool-coloured objects. A red or orange object against a green
or blue background will have a sense of depth.
The perception of size is influenced by colour and grey scale.
Open and light forms are perceived as being larger than closed
and darker forms of the same shape. The perception of size is
very much influenced by contextual variables. Large cannot exist
without small.
Tonal perspective
Light tones appear to advance and dark tones appear to recede.
A light object against a dark background will normally stand for-
ward, with a strong sense of depth. This phenomenon is called
tonal perspective.
In practice, it is difficult to distinguish between aerial per-
spective, colour perspective and tonal perspective. They are so
closely interrelated that they may be regarded as different as-
pects of the same thing. When we take photographs of objects at
a long distance, both aerial and colour perspectives may be in-
tensified by the use of special lenses and filters.
Overlapping perspective
When certain objects are placed in front of other objects this will
enhance the impression of depth in a picture. The overlapping
perspective was quite common in European mediaeval art. The
overlapping perspective, cropping perspective, or playing-card
98
perspective should always be used with cautiousness–in a cor-
rect, logical, well thought-out and consistent manner. Otherwise,
the risk of misinterpretation is obvious.
Shadow perspective
In a shadow perspective projected shadows, or drop shadows,
are sharply accentuated as a means of displaying the location of
different objects and their spatial relations to each other. Even
some of the old rock paintings in caves reveal attempts at pro-
ducing an impression of depth, by the suggestion of simple cast
shadows. In schematic pictures and in news graphics a cast
shadow behind individual picture elements, or behind two edges
of the complete picture, may create feelings of three dimensions
and depth. If this is done correctly, the picture seems to be float-
ing above the page.
Cast shadows may create confusion and they may actually
impair legibility and communication. In particular, it is confus-
ing when the shadows in a picture are of different sizes, implying
three-dimensionality and a perspective that neither exist nor
need to exist. Sometimes shadows may fall in different directions
in the same picture. Avoid all kinds of drop shadows behind pic-
ture elements in schematic pictures! Drop shadows will impair
the reading of the actual data and information in the pictures.
Other positional perspectives
The remaining positional perspectives comprise two types. These
are geometrical perspective, and multi-view perspective.
Geometrical perspectives
The placement of objects within a picture is very important in
geometrical perspective. This is common among traditional Jap-
anese and Mayan artwork. Here, objects close to the viewer are
shown in the lower part of the picture. Objects that are further
away from the viewer are shown in the image above the near ob-
jects in the lower part. The most important figures are often
shown as the highest in a composition. Objects further away may
99
be placed on a vertical line, as steps on a ladder. This is some-
times called vertical perspective. Geometrical perspective is
quite common in children’s drawings.
Multi-view-perspectives
In multi-view perspectives, different views appear at the same
time. The pictures of young children, like many of the paintings
from ancient Egypt, India, and pre-Renaissance European art
depict objects independently from their surroundings. The pic-
tures show objects as they are known to be rather than as they
are seen to be. Objects and figures are shown in multi-view per-
spectives from all the different views that best present their most
characteristic features. In many Egyptian paintings, the head and
legs of a person are shown in profile, while the eye and torso are
shown frontally. This system produces a sense that objects and
surroundings have been compressed within a shallow space.
Central perspective was considered the only correct type of
perspective in Western art until Modernism started to question
laws of construction. At the end of the 19th century Paul Cézanne
flattened the conventional Renaissance central perspective. In-
spired by Pablo Picasso, the cubists broke off completely with the
traditional conception of space, and modern art became totally
liberated from the time-honoured laws of perspective. Today
modern art, oriental art, and illustrations in children’s books of-
ten use multi-perspectives or multi-view perspectives.
Psychological perspectives
The second main group of pictorial perspectives is psychological
perspectives. These perspectives are visualisations of psycholog-
ical and subjective sets of values and illusionistic effects. This
group includes imaginary perspective, simultaneous perspec-
tive, and value perspective.
Imaginary perspective
During the Baroque era, a special perspective was used in Euro-
pean architecture and pictorial art for the purpose of creating
100
illusionistic effects, the false perspective or the imaginary per-
spective. The artists made individual interpretations of what they
saw and represented these ideas in their paintings. During the
Baroque in Rome, both the Italian painters Giovanni Battista
Gaulli, or Baciccia (1639–1709) and Andrea Pozzo (1642–1709)
became famous for their ability to “fool the eye.” Baciccia created
interiors as illusionistic masterpieces. Pozzo created a number of
religious ornaments in churches. The viewer perceives the pic-
ture as a continuation of the real space.
When we convey information in information design and in-
struction design, the purpose is the opposite: to present facts as
clear and unambiguous as possible. Modern examples of imagi-
nary perspective are found in pictures created by means of spher-
ical lenses.
Simultaneous perspective
In European medieval simultaneous perspective, time is a spatial
dimension in paintings. Several manifestations of the same char-
acter or person may be seen in one picture. The allegories, icons,
and symbols that are used determine to a large degree the inter-
pretation of medieval images. Several manuals with directions
for understanding visual arts have been published. One very im-
portant example is the book Iconologia, written by the Italian art
historian and scholar Cesare Ripa (c. 1560–c. 1645). He worked
as a cook and butler for the Cardinal Anton Maria Salviati. In his
free time, he studied the symbolism in Egyptian, Greek and Ro-
man emblem books (Wikipedia, 2013b). The Iconologia is a di-
dactic illustrated book with a collection of erudite allegories.
Iconologia was first published in Rome 1593, and later in
eight more Italian editions, and eight editions in other languages.
Ripa was knighted for the success of the book. For more than
three hundred years experts in art history in Europe used Icono-
logia as their prime source of knowledge when they discussed
description, identification, interpretation of the content of clas-
sical art. Art historians have learned, and know the language of
101
art. However, this is, and was, not true for people in general. The
general public lack these necessary frames of references.
Value perspective
In art of more ancient date, and even in primitive art, there are
many examples of perspective based on contents, meaning, and
value. The significance, rank, status, or value of depicted objects
is evident from the object’s size in the picture. Geometrical and
mathematical laws are set aside. In Egyptian traditional art, the
gods are larger than Pharaoh, who in turn is considerably larger
than all his subjects. In several Middle East countries today, the
most important person in a group picture is larger in size than
the other, less important people. Leaders who happen to be short
appear to be “big” leaders since they are the largest in the group.
This is also a gender issue. Lester (1995) noted that (p. 49):
In a picture of a couple, the man’s dominance over the
woman often is signified by the man being nearer and larger
in the frame with his hand resting on or arm wrapped around
the woman’s shoulder. Over the past two decades, feminist
movement has made advertisers and others more sensitive
to nonverbal, negative stereotypes such as these.
This kind of perspective is also called value perspective, and so-
cial perspective.
102
Picture editing
We can delete, add, or relocate data and information. Graphic el-
ements that constitute boundaries between different image ele-
ments are more important to our perception of the image than
other graphic elements. In principle, it should be possible to de-
lete a rather large number of non-significant elements in, e.g., a
photograph. As long as some of the significant picture elements
are retained, we can still get some idea of the image content. So,
image design can be changed a great deal without any major
change in the perception of image content.
This main section includes the following sections: Why pic-
ture editing, Selection of pictures, Cropping, Changing scale,
and Text in pictures.
Why picture editing
McDougall and Hampton (1990, p. ix) explained that picture ed-
iting does not deal in absolutes. Taste and judgement are essen-
tial because so many variables can influence editing decisions.
When we find “good” pictures we can’t take for granted that we
can use them as they are. There is usually a need for cropping
and/or changing the scale of selected pictures. Sometimes it is
also possible to manipulate the picture by changing the projec-
tion, expanding or compressing the image, changing, adding, de-
leting, moving, or turning specific picture elements in various
ways. However, in most of these cases we need to get permission
from the copyright holder/s to do any manipulation with the pic-
tures. McDougall and Hampton (1990, p.2) provided the follow-
ing seven questions as an approach to picture editing in visual
communication.
• Is the picture informative; is it interesting?
• Do camera and darkroom or electronic techniques reinforce
the message?
• What words are needed to strengthen the message?
• Will cropping improve the content or composition?
• What is the minimum reproduction size for readability?
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• Does one picture say enough or would two or more be better?
• How will layout best convey the message?
Wileman (1993) and a number of other authors have described
different methods for the editing of visuals to change their im-
portance and impact. Some important changes that can be made
to a visual prior to publication should be mentioned. For exam-
ple, a picture editor may elect to crop or expand the original pic-
ture. Parts of the picture can be deleted, added, altered, moved
or changed in shape. The picture can also be enlarged or reduced.
A colour can be changed, removed or added. The picture’s ex-
pressiveness can be altered by the choice of repro method etc.
Selection of pictures
Different people perceive and describe any given event in differ-
ent ways. Photographers, journalists, editors and graphic design-
ers may all have different priorities and they may make separate
selections. This means that readers and viewers have completely
different opportunities to interpret what has actually happened
in connection with a given event.
Every published picture has been selected, not only once but
usually several times. First the picture creator, the photographer,
and/or the artist selects the subject matter. The photographer
makes the initial decision as to how much or how little of a situ-
ation will be on the film, or in the memory card. In any given sit-
uation, a lot of different pictures may be produced. Then the ed-
itor, art director, and/or the designer selects among various pic-
tures in a collection or in a picture archive. In instructional ma-
terials, a picture should never be used just because it is pretty.
Every picture should have some information to convey–if it
doesn’t, it should be left out.
There is often a clear difference between the intended and
the perceived message (Pettersson, 1985). One way to decrease
this gap is to supply all pictures with interesting and explaining
captions, supporting the intended interpretations (Melin and
Pettersson, 1991). When too many pictures of different types are
104
used in one single message, some of the pictures may be ignored.
There will also be less space for the text. Unfortunately, often ar-
chive pictures are used in a way not intended. Sometimes the
same pictures appear in several different contexts, which may
confuse the readers.
Pictures may even have a negative effect. Some illustrations
(often without captions) in contemporary textbooks appear to
serve no useful purpose at all. Some picture editors admit that
some of the pictures they put into textbooks are only there to
“stimulate” the reader, to have “a life of their own,” or merely to
provide a “breathing space” within the text. Such uses seem very
dubious. In fact, some publishers admit that the two main rea-
sons to use pictures in their books are to: 1) Attract buyers, and
2) Increase the prices of the books.
Interviews with art directors, designers, and editors from
major Swedish publishing houses showed that they, in the selec-
tion of visuals for reference books and textbooks, often ask them-
selves questions such as the following (Pettersson 1989, p. 145):
• Does the picture depict the right thing?
• Is the presentation of the subject satisfactory?
• Is the picture technically acceptable?
• Is the picture aesthetically satisfactory?
• Is the picture “flexible,” i.e., will it work with different for-
mats?
• Will the picture fit into a given area?
• Will the picture fit in with the other pictures on the same
page?
McDougall and Hampton (1990, p.3) recommended three prag-
matic tests for judging photo merit in the context of journalism.
The tests concern message, aesthetics, and technique.
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Message
• Does the photo make a clear statement?
• Does the photo meet the ethical standards of responsible
journalism?
• Does the photo invade the privacy of its subjects or libel
them?
Aesthetics
• Is the photo’s composition well organized and aesthetically
appealing?
• Does the composition facilitate the message?
Technique
• Do the camera and darkroom techniques enhance the photo’s
message?
• Is the photo of press reproduction quality?
Preference for a particular visual format does not necessarily re-
sult in increased learning. Yet, in the absence of more substantial
data, information based on student preference has a meaningful
role to play in affecting learning from information materials and
instructional texts. All other things being equal, we should pro-
vide formats that are preferred by the viewer, thus making the
text more attractive, and hopefully more motivating. Thus, selec-
tion of artistic style for visual materials should not be an arbitrary
decision, but always a conscious one.
Although full-colour photographs increase the costs of trade
books Ramsey (1989) suggested that publishers should increase
the number of such books available for primary audiences. To-
day, however, there are only few informational books for children
which meat these criteria. It is actually quite common that vari-
ous kinds of abstract illustrations are used in textbooks.
Visuals for information should be attractive but “unambigu-
ous,” i.e. not too “artistic” and ambiguous. Visuals that are attrac-
tive and that people like also have greater impact. To increase in-
terest in a material it might be a good idea to use a blend of
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several kinds of visual types such as diagrams, drawings, and
photos. Generally speaking it is not possible to rank the different
types of visuals. Often the type of visual that should be used must
be determined in each individual case with a view to various de-
mands on the picture and the prevailing budget framework. It is
often easier to control the production of a drawing than the pro-
duction of a photograph. So, a drawing may be the only realistic
alternative in many situations.
However, since pictures illustrated in more abstract styles,
such as cartoon and expressionistic, might generate more imagi-
nation such pictures might be used as stimuli for creative writing
assignments. It is not enough to select good visuals and make
sure that all the pictures have relevant captions. To really help
the readers to improve their use of visuals in textbooks, AV-ma-
terial, and other teaching aids, we should give the teachers care-
ful guidance, for instance in a teacher’s guide. The guide should:
• Show the purpose of each individual picture.
• Complete the caption and tell what each picture shows
• Give different examples of how every picture can be used in
the education, what is important to discuss, which tasks can
be assigned in connection with the picture, and so on.
• If needed provide complementary facts, for instance explain
how the picture has been produced.
• Account for name of photographer, artist or another picture
creator.
Effective visuals for information should create an experience for
the reader. The reader must:
• See or rather “discover” the picture.
• Pay attention to the picture.
• Read the picture in an active and selective way.
• Process the information mentally.
Winn (1993) concluded that pictures play many roles in instruc-
tion. It is necessary to know precisely what a picture’s function is
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intended to be before it is designed. Cognitive and decorative
functions should never be confused or mixed (Pettersson, 1989).
As previously mentioned we should remember that pictures
might have a negative effect. Illustrations move from being en-
gaging motivators to engaging distracters at some point (Evans,
Watson and Willows 1987). When too many pictures are used,
readers may ignore many of them. Massoumian (1989, p. 19)
noted, “Haphazard use of visuals may lead to minimal or no in-
structional gain and gradual loss of effectiveness as an instruc-
tional tool.”
Visuals cost money, often quite a lot of money. But in many
situations a “good” picture need not cost more than a “bad” pic-
ture! Spending a lot of time on the visualisation process and on
sketches (usually a less expensive process than the cost of origi-
nals, “masters,” and printing runs) may be worthwhile. Usually
several sketches or outlines make a basis for decisions necessary
in the production of the final drawings.
A selected photo often needs cropping. By cropping, distract-
ing and/or uninteresting parts of the image will be eliminated.
Pictures should always be adjusted to fit into their final context.
Image framing makes a clear distinction between image and
background. Fading is used to make the image gradually appear
on the page. Layout is the integration of text and images, i.e., on
an opening in a book. Captions give the reader necessary guid-
ance in understanding the image content.
Pixley (2020) performed critical, and participatory action
research that presents collaborative efforts to intervene in pre-
vailing racial narratives of professional photojournalism. Photo-
journalistic production is a combined work: the authorial work
of the photographers in the field, and the authorizing post-pro-
duction labour of the newsroom photo editors. Pixley (2020, p.
120) concluded: "there are glimmers of change within the indus-
try, rapidly expanding and intersecting.”
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Cropping
An original picture can often be improved by removal of irrele-
vant or distracting elements. Usually pictures can be cropped a
little bit from all sides. In practice the photographer always per-
forms some “initial cropping” while taking the actual photo-
graph. When composing or taking a photograph, the photogra-
pher sets the boundaries or “frame” of the picture. The same is
also true for the artist who makes a “mental cropping” before
s/he starts the actual drawing process.
The picture editor should not manipulate the meaning of the
photo by cropping off people so that the relationships among
those remaining are changed. This happens sometimes in news-
papers and also in books. McDougall and Hampton (1990, p. 94)
provided an example that may be the most notorious example of
manipulating our perceptions of truth by cropping. The USA
Senator Joseph McCarthy feared that communists were taking
over America. He accused people with power, including the gov-
ernment, large American institutions, and the United States
Army.
During the “Army-McCarthy Hearings” in 1954 McCarthy
used a cropped photo in an attempt to discredit Robert Ten
Broeck Stevens, who was the “Secretary of the Army.” The origi-
nal print showed four people standing by a military plane.
McCarthy had the two men at the left cropped out to make it look
as if Stevens were friendly with a former McCarthy aide. Attorney
Joseph Nye Welsh’s exposure of the fraud led to McCarthy’s ruin.
In order to demonstrate cropping, I will use one of my own
pictures from an interesting visit in 1999 to the hot springs in
Yellowstone National Park in the USA.
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This is one of my own pictures from an interesting visit in 1999
to the hot springs in Yellowstone National Park in the USA. The
picture may be even more interesting if we crop it.
To find the most interesting part of an image you can use two
L-squares if you want to publish a picture for example in a report.
When you work with a printout, or a photographic copy on paper,
you can use two simple “L-shaped pieces of hard paper”. Move
these L-squares around on top of your image until you find the
best cropping possible. (See an example of simple L-squares on
the next page.) Mark the desired cropping on an overlay or on a
plain photocopy of the picture. Always be very careful with any
original print. Never use a knife or a pair of scissors to cut out
your specified section of a photographic copy on paper. Use a
transparent overlay and clearly mark all corners with thin lines
for the part of the picture that you want to publish. The actual
“cropping” is usually done in a scanner at the print shop. You also
have to tell the printer about the exact size of each picture.
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We can use two simple L-squares in order to find out if cropping
will improve a picture. Move the L-squares around until you
find an interesting part of the picture.
In desktop publishing systems, you can make the cropping
of an image digitally in a digital copy or duplicate of the original
picture. You can store two “digital L-squares” on separate “image
layers”, and use them to define the image area that you want to
include in your report. Then you just need to remove all the other
parts, and save the picture in the correct size, with a new “identity
code”, or “name”, for your publication.
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These two pictures are duplicated, cut, and enlarged.
A complicated picture can often be cropped and divided into
two or more parts, each supplied with their individual captions,
and “identity codes”. Sometimes images can be cropped to non-
rectangular shapes, like ovals or soft round(ed) shapes.
The ratio of face to body, the “face-ism ratio,” influences the
way we perceive a person in an image (Lidwell, Holden, and But-
ler 2010, p. 88). When a face takes up most of the space in an
image we will focus on the person’s intellectual and personality
attributes. When the body takes up most of the image we will fo-
cus on the person’s physical and sensual attributes. News media
often focus more on faces of men and bodies of women. Face-ism
ratio is also called “facial prominence.”
Cropping and changing of scale are the most common
methods used in picture editing.
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Changing scale
Pictures should always be adjusted to fit into their final context.
An image may be scaled up or down. There is an optimum size
for each visual. The actual content remains the same but the cho-
sen scale can influence our perception of the content.
A picture can be reduced and enlarged in the same propor-
tions as the original if the new dimensions meet at the diagonal,
or extended diagonal, of the original. This is called the “diagonal
line method of scaling.” Draw a diagonal on an overlay on top of
the image. Decide on the desired width of the scaled version, and
then measure the height. Or do it the other way around. There is
an easy “algebraic proportion equation” which we can use for
scaling. The original width is to the original height as the repro-
duction width is to the reproduction height (w1/h1 = w2/h2).
This “combined picture” illustrates how an image (1, the one in
the middle) can be reduced (2, the small one in the corner), and
how it can be enlarged (3, the large one). When scaling w1/h1 =
w2/h2 = w3/h3.
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The “Brandt Scaleograph” is a mechanical aid that uses
semi-transparent “Ls” that slide on a metal rod representing the
diagonal of a rectangle. The “Proportion wheel scale” has two
wheels. An outer wheel represents the reproduction size and an
inner wheel represents the original size.
The size of the visual should be large enough for the image
to be legible. If the plane of projection is changed the relations
between various parts in the picture will be influenced. Usually
drawings are produced in a larger size than the intended size in
the finished product. When scaling down, lines get thinner,
tighter, sharper, and more distinct. Drawings look better because
lines appear to be more confident. However, small details may
often disappear. Scaling up has the opposite effect. Lines tend to
dissolve and small mistakes become even more obvious.
The cat in the middle is the original bit-mapped digital image.
We lose data when we reduce this image (left), and no data is
added when we enlarge the image (right). Thus, it is better to
create bit-mapped images in the correct sizes.
A bit-mapped image, created and stored in a computer, may
be scaled. However, no data will be added when the image is
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enlarged and important data will be lost forever when the image
is reduced. Thus, it is better to create all bit-mapped images in
the correct sizes from the beginning.
Another possibility is to create a bit-mapped image in a large
size, scale it down with a repro-camera or with a copying machine
and then paste it as a new original. Object oriented objects may;
however, be scaled without any loss of quality. This is especially
good for schematic drawings. Sometimes it might be a good idea
to enlarge interesting parts of a picture. Several consecutive en-
largements of a specific part will help the reader to understand
the detailed structure of an object.
Text in pictures
Texts within pictures should usually be printed in Helvetica nine
or ten-point, normal style, and should be as concise as possible.
As a rule, texts within a picture element should be centred. Make
sure that words or whole texts do not spill over different picture
elements, as this will make both the picture and the text difficult
to read. When a heading is needed it may be set in nine-point
bold Helvetica. Avoid using several lines of text inside a symbol.
It is difficult to keep distances consistent inside different sym-
bols, and it is easier to read one short line than several lines.
Sometimes it may be a good idea to consider labelling graphics
in multiple languages.
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Image manipulation
As a medium photography has always maintained a complicated
relationship to visual reality (Ogden, 2012). Limitations of the
medium caused some pictorial falsehoods in the nineteenth cen-
tury. In the twentieth century the properties of specific camera
lenses created some pictorial falsehoods. Some photographers
manipulated their photographs during the shooting processes,
the printing processes, or both. Photo manipulation has a long
history, almost as rich as the practice of creating actual photo-
graphic images (Brugioni 1999).
This main section includes the following sections: Views on
image manipulation, Digital image manipulation and A defini-
tion of image manipulation.
Views on image manipulation
There are pictures almost everywhere. Regardless of our wishes,
we are constantly confronted with numerous visual impressions.
We see pictures in public places, on TV, at the cinema, in books,
newspapers and periodicals, on various types of packaging and
in many other contexts as well. Never before have we had access
and been exposed to–or the victims of–as many pictures as exist
today. It is obvious, and perhaps a good thing, that all pictures
are not salient at every separate occasion. Many actually drown
in the general media noise
Conscious and perhaps even unconscious deception, falsifi-
cation and manipulation of pictures–through tampering, biased
selection or improper captions–occur rather often, resulting in
readers being manipulated, deluded and misled (Pettersson,
2002). Readers are seldom or never able to judge for them what
has happened before or after the moment a photograph was
taken. Nor do they know what occurred in proximity to the situ-
ation in question. In one study (Pettersson, 2002) subjects were
asked to answer the following five questions.
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• How do you define the concept image manipulation?
• What media do you think use image manipulation?
• How common do you think that image manipulation is?
• What do you think about image manipulation?
• Can you see if an image is manipulated?
A total of 186 subjects wrote their answers on special forms. After
registration of participation it was no longer possible to link any
opinion to a specific person. Most subjects were between twenty
and thirty years old. The 930 answers to the five questions pre-
sented more than 1,300 opinions about image manipulation. In
this study it is not possible to distinguish between opinions from
female and male subjects.
Definitions
The answers to the first question (“How do you define the con-
cept image manipulation?”) can be divided in categories of de-
scriptions rather than definitions. The students have used 390
verbs or expressions in their descriptions.
Most of the descriptions (86%) explain how the “sender”
somehow makes changes in the picture. Quite a few descriptions
use similar expressions. In some cases, synonyms are used. In
the second group (14%) some answers describe “possible objec-
tives” for the image manipulation. Thus, these descriptions rep-
resent another perspective on the concept image manipulation
than the first group. The five most common verbs are change
(28%), transform (15%), add (8%), delete (8%), and distort (7%).
We may note that some subjects mix up and confuse image and
reality. For example, four individuals have answered, “Improve
reality.” They probably mean, “Improve the image of reality.”
Media
The answers to the second question (“What media do you think
use image manipulation?”) were sorted in such a way that similar
answers and answers with basically the same contents are put in
“media groups.” This question resulted in 368 explanatory ex-
pressions for media. The most frequent answers include 1) print
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media (33%), 2) television (19%), and 3) “all” or “most” media
with images (19%).
Occurrence
The answers to the third question (“How common do you think
that image manipulation is?”) were sorted in such a way that sim-
ilar answers with basically the same contents are put in “types.”
Subjects provided 186 explanatory answers. Most students (91%)
consider image manipulation to be “frequent.” A small group
(6%) view image manipulation to be “uncommon.” A few subjects
(3%) do not know that image manipulation may occur or they
have no comments.
Opinions
The answers to the fourth question (What do you think about im-
age manipulation?) may be put in five groups:
• Image manipulation is a good thing. (6%)
• Image manipulation is acceptable when this is clearly noted.
(7%)
• Sometimes image manipulation is acceptable. (68%)
• Image manipulation is wrong. (14%)
• Other views. (6%)
Thus, a small portion of the subjects (14%) view that image ma-
nipulation is wrong. However, a clear majority have the view that
image manipulation may be acceptable. According to many of the
answers “the context, the specific situation and the objective of
the sender” defines if image manipulation is acceptable or not.
The subjects also accept image manipulation in some media,
such as magazines, when the topic is “fashion, advertising and
propaganda.” In fact, several subjects expect the use of image
manipulation in these media. To “improve, simplify and enhance
image quality” are also quite acceptable to many of the subjects
in this group.
Increased knowledge may make an individual less suscepti-
ble to visuals manipulations or become more broadly aware of
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manipulation inherent in all visual messages (Fahmy, Bock, and
Wanta 2014).
Does it show?
The fifth question (“Can you see if an image is manipulated?”)
was used to clarify to what extent subjects feel that they can see
if an image is manipulated or not. The answers from the 186 sub-
jects may be put in three groups: 1) No, and denying answers
(60%). 2) Hesitating answers (17%). 3) Yes, and affirmative an-
swers (23%). Thus, most of the subjects hold the opinion that
they are not able to see if an image is manipulated. However, al-
most one quarter of the subjects feel that they are able to see if
an image is manipulated.
Validity
It may be reasonable to assume that this group of subjects have
the same, or similar, opinions as other groups of subjects and as
the general public regarding the definition of image manipula-
tion. This would also be true for opinions about the occurrence
of image manipulation in various media. However, with respect
to opinions about the occurrence of image manipulation this
group may differ from the general public. It is reasonable to as-
sume that information design subjects are more aware about im-
age manipulation, and how easy it is done, than other groups of
people. This would also be the case for opinions as well as if it is
possible to see and detect if an image is manipulated or not.
Digital image manipulation
Digitally manipulated photographs began to appear in the daily
press in the mid-1980s (Alling-Ode and Tubin, 1993; Becker,
1996; Paul, 2000). The introduction of digital pictures and elec-
tronic transmission of pictures has had a radical effect on how
pictures are dealt with at various stages of production (Petters-
son, 2002) as well as on how readers perceive these pictures
(Ritchin, 1990). Technical development has fundamentally
changed our presumptions concerning credibility in photo-
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graphs. Photos need no longer have natural ties to the film-based
original (Fetveit, 1997).
Here, I have digitally manipulated my own image of a male
mallard (left). I have duplicated and pasted the mallard twice,
then smoothed the waves in the water (right).
Using modern computers and graphics processing pro-
grams, one can, in principle, make any conceivable change in
drawings and photographs as well as in moving pictures on film
or video from the very moment the photograph is taken until it is
published. For a person with the necessary skills and access to
the right equipment, there are almost no limitations (Hedgecoe,
1994). Thousands of pictures of various standard backgrounds
and foregrounds–depicting different types of landscapes, city en-
vironments, people, plants, animals, etc.–can be combined to
form an endless number of entirely or partly new picture motifs.
In this context, naturally, interesting ethical questions arise,
which are neither trivial nor in any way easy to answer.
Regulations
Modern computer-based graphical systems have a lot of built-in
possibilities for manipulating images. However, usually we need
permission from the copyright owner, and–from an ethical point
of view–also from any person in the picture. It seems that photo
manipulation has become a common practice for many graphic
designers working in advertising and entertainment. However,
in news, information design, and instruction design, readers and
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viewers expect pictures and images to represent the truth in a
correct way.
In Sweden the law relating to photography ceased to be in
effect on 1 July 1994. At this point regulations concerning the
right to photographs were subsumed under the copyright laws.
The financial and idealistic interests of photographers, authors,
draughtsmen, songwriters and other originators of creative
works are protected by the copyright law relating to literary and
artistic works (Copyright Act, URL, SFS 1960:729).
Since 1 January 1996, artistic works are protected for the
originator’s entire life plus an additional 70 years. Thus, many
works are protected for more than 120-130 years. This protection
is international. The economic right implies the sole right of the
originator to determine duplication of the work–the making of
copies and presentation of the work in public. For “picture theft”
occurring intentionally or through gross negligence, the penalty
is fines or imprisonment for up to two years.
Modern computer-based graphical systems have great built-
in possibilities for manipulating images. However, usually we
need to have permission from the copyright owner, and–from an
ethical point of view–also from any person in the picture. It
seems that photo manipulation has become a common practice
for many graphic designers working in advertising and entertain-
ment. However, in news, information design, and instruction de-
sign readers and viewers expect pictures and images to represent
the truth in a correct way.
Artistic works are protected for the originator’s entire life
plus an additional 70 years. Do not manipulate pictures!
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Digital retouching. It is easy to change individual pixels in a pic-
ture, and thus get rid of dust, hair, and scratches. These pictures
show the same DC-3 flying low over Stockholm, Sweden.
Modern computer-based graphical systems have great built-
in possibilities for manipulating images. However, usually we
need to have permission from the copyright owner, and–from
an ethical point of view–also from any person visible and pos-
sible to identify in the picture.
It seems that photo manipulation has become a common
practice for many graphic designers working in advertising and
entertainment. However, in news, information design, and in-
struction design readers and viewers expect pictures and images
to represent the truth in a correct way.
The ethical rules for the press, radio and TV clearly take ex-
ception to manipulation and falsification of picture content
through trimming, montage or misleading captions (Bildleveran-
törernas Förening, 1999; Harrie, 1999; Pressens Samarbets-
nämnd, 1999). Presenting inauthentic pictures as though they
were real documentary material is forbidden. The party purchas-
ing the pictures is responsible for their proper use. Despite these
rules, clear violations occur all too often, in Sweden as well as in
many other countries.
Photographers and draughtsmen as well as their organisa-
tions stipulate in their terms of delivery that published pictures
shall be correct. Those purchasing the right to publish the pic-
tures are not allowed to use them in a misleading manner. Nor
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may they make a picture montage or retouch electronically such
that the results can mislead or delude the reader or viewer. To-
day, one does not have the right to change the content of any pic-
ture without the express permission of the holder of the right to
that picture. In accordance with Cifuentes, Myers and McIntosh
(1998) the Associated Press has adopted photo manipulation
guidelines to prevent dishonest reporting (p. 170):
• The content of a photograph will never be changed or manip-
ulated.
• Only the established norms of standard photo printing meth-
ods such as burning, dodging, black-and-white toning, and
cropping are acceptable.
• Retouching is limited to removal of normal scratches and
dust spots.
• Serious consideration must always be given in correcting col-
our to ensure honest reproduction of the original.
• Cases of abnormal colour or tonality will be clearly stated in
the caption.
• Colour adjustment should always be minimal.
Digital deception
However, sometimes digital photo manipulation, or digital de-
ception, may enhance a message, and sometimes it should be
used for better communication. It is possible to modify an image
in several different ways. We can add, change projection, com-
bine, compress, delete, expand, isolate, modify, move, reduce,
supplement, and turn, various parts of an image.
In order to demonstrate digital deception, I have manipu-
lated one of my own pictures from an interesting visit in 1999 to
the hot springs in Yellowstone National Park in the USA.
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This is again one of my own original photos from a visit to the
hot springs in Yellowstone National Park. The picture shows
five, for me, totally unknown tourists. I have later duplicated
the picture, and digitally modified the following three pictures
in order to demonstrate some aspects of the concept “image ma-
nipulation”.
Additions
The relation between height and width of an image can be
changed by the addition of space at the right, bottom, left or top
sides. Arrows, circles, letters of the alphabet, lines, numerals, and
other markings and symbols can be added to a picture for the
purpose of enhancing image content and focusing attention to
specific parts of the image and links to the caption. The super-
imposition of text onto an image usually impairs our ability to
absorb the contents of both image and text.
Groups of picture elements can be copied from one place in
an image and moved to one or more other positions within the
image. It is also possible to move parts of an image to other pic-
tures. Parts in a picture can be added by painting with an
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appropriate retouching colour or shade. Image framing makes a
clear distinction between image and background. An image may
be framed in a frame appropriate to the subject. The frame may
be a keyhole, a window, or the like.
Here a number of “new persons” are digitally created and
added to the original image. Now, it is almost crowded on the
walkway. This will change our perception of the image content.
Changes
To focus the reader’s attention on the main content in a picture,
individual picture elements can be changed so as to improve acu-
ity, colour scale, contrast, grey scale, and sharpness. Surround-
ing parts can be made darker, out of focus, or paler. The visual’s
external contour can be blurred and unclear so the picture fades
in/out of the background. Good photographers select focusing
and depth of field to achieve the same goal–better clarity and
better communication. Sometimes the grey scale can be trans-
formed into optional colours.
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Individual picture elements, as well as groups of picture ele-
ments, can be moved or turned around within an image for the
sake of better balance and harmony. Groups of picture elements
can also be copied from one place in an image and moved to one
or more other positions within the image. It is also possible to
move parts of an image to other pictures.
A picture can be tilted on the page at will. Tilting of a picture
may draw special attention to it. Distracting or undesirable de-
tails in a picture can be removed by painting with an appropriate
retouching colour or shade. This is also a way to isolate parts of a
picture by, say, cropping and peeling. The detail can then be used
independently or as a part of other pictures.
To achieve emphasis, it is common to add information such
as colours, contrasts, shadows, signs, and symbols.
Changing projection plane
The projection plane can be altered through digital image modi-
fication or shrinkage. This process will distort all the size rela-
tionships within the picture and it may have a serious effect on
our perception of the contents in the image.
Many people have experienced, and may remember this
problem, from the past. Many presenters used their “home-
made” and analogue OH-transparencies, or sometimes filmstrips
or slides, and never fully understood the importance of a proper
set-up of projectors and screens. Since a few decades we experi-
ence the same problems with modern Power Point Presentations,
as well as other, similar digital systems, because many presenters
have not yet understood the importance of a proper set-up of pro-
jectors and screens.
However, sometimes changing the projection plane may be
used in a creative way to enhance the content of your own image.
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It is very easy to digitally change the projection plane of any
image. This will however, usually only confuse the reader and
viewer. In this case the picture is more or less destroyed.
Compression and expansion
An image can be compressed, i.e., squashed from the sides or
from the top and bottom. It can also be vertically and/or horizon-
tally expanded or stretched. This will of course change the size
relationships within the image. Compression and expansion will
always result in a more or less serious distortion of the original
image. However, sometimes this can create useful effects.
Deletions
It is often easy to remove parts in a picture by “painting” with an
appropriate retouching colour. Sometimes it may be rather easy
to edit, and even totally remove, parts of a picture. In some cases,
people may use full silhouetting in order to get rid of all back-
ground disturbances. The outline of an image can also be sof-
tened.
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It is often easy to remove parts in a picture by “painting” with
an appropriate retouching colour. Here, I have deleted three
persons. One adult, maybe a mother, is now alone with a child.
Transforming photographs to artwork
McDougall and Hampton (1990) noted that converting photos to
art is a type of photo theft that picture editors should crack down
on. It is far too common that artists transform photographs to
artwork for use as illustrations in newspapers and in books. To
transform a photo into a drawing is not only unethical, it is also
often an infringement of copyright. McDougall and Hampton
wrote (p. 32):
The courts have held that a work of art which has been cop-
ied from another work which is copyrighted, regardless of al-
terations, is primafacie evidence of copyright infringement.
The courts have also held that copying a work of art in a dif-
ferent medium such as changing a photo into a drawing is
still a violation.
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There are, however, also examples of the opposite, where pho-
tographers work too close to drawings and paintings.
Manipulative captions
We can use positive as well as negative captions to describe any
picture. The content in the caption will influence our perception
of the picture. See the section Caption–picture relationships in
my book 3. Information Design–Text Design for examples of a
positive and a negative caption for a close up of this picture.
A definition of image manipulation
People used to make retouch on photographs using a brush and
Indian ink. Today such operations can easily be performed in the
computer. However, in my view it is not enough to consider this
kind of “surgical changes” in pictures as image manipulation. We
need to consider two quite different types of image manipulation.
• There is no change at all of any picture elements. However, in
propaganda the editor can direct and influence people’s per-
ception of reality in a desired direction through very well con-
sidered selection of pictures, and careful trimming, as well as
writing leading captions.
• Careful change and editing of certain picture elements in or-
der to influence people’s perception of the reality that the pic-
ture appears to depict.
Based on these distinctions I have proposed a definition of image
manipulation (Pettersson, 2002):
Image manipulation implies the improper control of peo-
ple’s perception of a given reality through the use of pictures.
Thus, effective use of computers and digital technology for edit-
ing and production of good quality pictures does not have to
mean image manipulation.
It is obvious that technical development has fundamentally
changed conditions for our ability to use pictures in different
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contexts as well as for the credibility of all pictures. In practice,
individual newspaper readers and TV viewers no longer have any
real opportunity to discover whether a published picture has
been manipulated or not. Since computer technology is develop-
ing rapidly we can hardly assume that this situation will improve
in the future. With each passing year, it becomes easier for any-
one to create and revise pictures and make them accessible on
the Internet. Deception and mistakes exist within news report-
ing. So far, we don’t know how to answer these questions:
• How can we best ‘protect’ ourselves from being manipulated
by news reporting?
• Can we trust pictures?
• How can we expose deception?
We can, of course, hope that the established media actually
assume their responsibility and live up to their own rules. Rules
and ethical norms are already in place, but it is evident that all
people working in media are not aware of their responsibility. In
the long run lack of responsibility could lead to a credibility cri-
sis. If we become accustomed to deception, our trust in the media
will diminish.
Good rules and norms, however, are not enough. What is
also needed is that people working in media learn them, and that
readers and viewers adopt a critical approach to media. To
achieve this, pictorial communication, critical analysis and
source criticism must become a real and natural feature of teach-
ing in school.
It is conceivable that future generations–growing up with in-
creasingly advanced computers and learning to use them early in
life–will develop a freer and more independent approach to pic-
tures and pictorial communication than the one characterising
adults of today. Children who learn to work with pictures on com-
puters should find it easier to understand what can be done.
When these children are grown, pictures will no longer have any
“natural credibility” for them (Pettersson, 2001b). They will not
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expect, for example, that advertisement pictures even attempt to
reflect any form of objective reality. At this point, we know little
about how pictures function as communicative expressions. In
my view, there is a great need for development work, discussions,
education, and research regarding the role of pictures.
Image contexts
The context and the medium in which a visual message is pre-
sented has a major impact on the way the message is perceived.
For example, the context may consist of text, music, sound ef-
fects, speech, or other visuals. This main section includes the
following sections: Internal context, External context, and Per-
sonal context.
Internal context
In a book the internal context is the interplay between texts, il-
lustrations, and layout. We may also discuss the relationships be-
tween the image elements within a single picture.
Graphic design is a tool with which we can manipulate the
raw materials–words in different typefaces, sizes, styles, empty
space, illustrations, colour, paper and ink, and the final number
of pages–to achieve the best possible communications between
people. Most people read instructional materials selectively. The
goal for graphic design should be clarity of communication. Ty-
pography for information, or typography for instruction, aids
communication and is also aesthetically pleasing. Further see my
book Graphic Design.
In this illustration one pattern is identified as the letter “B” in
the first sequence, and as the number “13” in the second se-
quence. Context is very important for our perception.
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Movies and TV programs have sound with speech, music,
and sound effects, plus visual and audio metaphors. When we
view a film or a television program our attention is either on the
image or on the sound. We may not be able to attend to more
than one stimulus at a time. At several conferences I, and many
others, have experienced this when the speakers use different
media at the same time. As soon as a film starts, our attention is
directed towards the movement in that film, away from any sur-
rounding still pictures or physical objects. It is just impossible for
viewers not to be influenced by the movements in the film. Some
computer programs contain advanced animations with interac-
tion between text, images, and sound.
External context
Several factors can be regarded as external context variables. In
an oral presentation the audience is influenced not only by the
presenter and her or his projected images but also by other things
like the temperature, the furniture, the room itself, outside noise,
noise from the projector, and noise from other persons. The
lighting conditions may be the most important variable for our
perception of all kinds of images. A projected image is perceived
as having high image quality in a dark room. When the light in-
creases, the perceived quality decreases. A printed image is per-
ceived as having high image quality in a light room. When the
light decreases, the perceived quality decreases.
A “poor” slide will always give a poor projected image, which
will be perceived as having low quality. A “good” slide with high
quality content and execution may be perceived as having any-
thing between low and high quality. When a “medium good” slide
is projected under optimal conditions, that image may be per-
ceived as better than a “good” picture which is projected under
poor conditions. Usually listeners have very small possibilities to
influence the lighting conditions and other contextual variables
in oral presentations. When there is too much light in the room
the images will be poor. However, when we watch television or
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read a book, a magazine, or a newspaper, we can usually adjust
the context lighting.
In graphical media the reader can spend, as much time as he
or she needs. This is also true for video. The viewer is usually free
to stop the tape and look at a specific sequence several times.
However, in oral presentations, in films, and in television, the
viewer has to follow the pace set by the sender or the producer.
It may sometimes be very hard to follow a presentation and be
able to accurately read the image content. Also, in oral presenta-
tions it is important to find the optimal pace. A slide should not
be on too long or too short. Quite often it is the length of the text
that decides for how long a specific image is used.
Personal context
Readers rarely, if ever, begin at the beginning and read a text
straight through to the end. Usually we use a combination of
browsing, reading headings, looking at illustrations and cap-
tions, reading certain parts carefully, skimming others, and
avoiding some parts completely. An illustration is a specialized
area of art that uses images to make an applied, visual presenta-
tion of a subject. Keller and Burkman (1993) noted that it is im-
portant to create a positive impression and give courseware a
comfortable image to gain and maintain learner attention and to
build confidence.
Text-relevant pictures facilitate learning from reading prose
(Levin, Anglin and Carney, 1987). When illustrations provide
text-redundant information, learning information in the text that
is also shown in pictures will be facilitated (Levie and Lentz,
1982). Learners are most able to build connections between ver-
bal and visual representations when text and illustrations are ac-
tively held in memory at the same time.
This can happen when text and illustrations are presented in
close connection on the same page in a book, or when learners
have sufficient experience to generate their own mental images
as they read the text (Mayer et al., 1995). In Nigeria “…most
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primary and secondary school pupils want to see visual illustra-
tions in their textbooks because it helps them to learn more ef-
fectively. All the teachers also believe that visual illustrations are
vital to teaching and learning at the primary and secondary
school levels” (Ajibade and Elemi 2012, p. 170).
Our perception of a stimulus is thus not only determined by
the characteristics of the main stimulus but also by those of the
context. This is, however, not the case with young children. A
background, which might give extra information to an adult
reader, cannot be assumed to fulfil the same function for a child.
It may actually hinder the child from perceiving the picture at all.
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Image formats
Our perception changes when we view an image as a photo-
graphic copy, as a printed picture in a book, as an image pro-
jected on a screen, as an image in a viewfinder, as an image on a
computer-screen, or as an image on a television screen, etc. A
movie evokes completely different perceptions when a viewer
watches it alone on a TV-set or in a crowded movie theatre with
a wide-screen and high-quality sound. An image is a multidimen-
sional representation of an inner or of an external reality, depict-
ing the physical structure of the objects or events it represents.
An image can also be described as a more or less complicated
sense of vision, i.e., awareness of the stimulation of the eye’s vi-
sion perception cells, with a specific message or content. An in-
ner image, a visual experience, can originate in thoughts and in
dreams. It may be caused by words, e.g., a picture description,
without any help of pictures. Every picture has different possibil-
ities of supplying a specific message. This depends on the choice
of material and type of production.
This chapter includes the following main sections: Image
morphology, Computer images, Graphical pictures, Photog-
raphy, Film, and Television and video.
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Image morphology
Mirror images and other virtual images can be seen but not “cap-
tured” and shown on a screen of any sort. A virtual image is lo-
cated in a point from which divergent light beams appear to start
before they have passed through the optical system. Like our in-
ner images, e.g. memories, virtual images lack an obvious physi-
cal format. All other kinds of images have a physical format.
This main section includes the following sections: Combina-
tions of small elements, and Analogue and digital coding.
Combinations of small elements
An artist or a painter producing a picture may use crayons, India
ink, lead, various kinds of paint, paper, canvas, and several other
kinds of materials in a variety of different combinations. Combi-
nations of dots, lines, and areas gradually produce the image. The
actual picture is built up from materials and pigments that, ac-
cording to intentions, can be completely separated or gradually
mixed. In technical systems the whole motif may be captured at
once with a traditional camera, or it may be scanned line by line
with a video camera.
Pixels
Except for the printing of line drawings, all other pictures have
to be divided into small picture elements, or pixels, in the tech-
nical processes in the printing of books, and in the broadcasting
of television. The image has a vertical (y) and a horizontal (x) res-
olution and it has also a “depth resolution” (z). An individual
pixel may vary with respect to colour, grain, grey scale, position,
shape, size, and value.
Normally these pixels are very small. At normal reading dis-
tance they can hardly be seen at all. When black and white pixels
are evenly distributed in an image, individual pixels become in-
distinguishable. An image with “good quality” must have a reso-
lution that is better than that of our own vision. Nature and all
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kinds of objects have got an infinite number of colour nuances
and shades of grey.
When we see the tracks and trails left by animals in snow, or
in soft mud these “visuals” may tell us a lot about the animals and
their activities. Skilled hunters are able to “reed” these visuals as
the rest of us read pictures in a book. Such a visual may consist
of just a few pixels. A single footprint from the hoof of a horse is
in fact a “one-pixel-picture.” Take a shower, a bath or a footbath,
and then walk across the floor. Your own footprints will be pic-
tures consisting of just a few pixels.
Perception
Our perception system can handle enormous quantities of data
under very different conditions. At any given moment, the eye
may contain 2,500,000 bits of data. We can see one detail that is
1,000 times brighter or darker than another detail. For 35-movie
film this range of contrast is 100 and for television it is only 10–
20. Yet our eyes are by no means “perfect” optical systems. The
eye has inertia. It takes time to read an image. This inertia ena-
bles us to see the motion in the stills that comprise movie film
and television. Movie film usually uses 24 pictures and PAL-tel-
evision 25 images per second. This is just below the so called
“flicker threshold” which lies at about 27–28 images per second.
At higher picture frequency the eye can no longer keep up. NTSC-
television uses 30 images per second and thus gives a more stable
television-image than PAL-television.
Millions of colour stimuli
It is possible for us to see the difference between several millions
of different colour stimuli at simultaneous viewing. However, if
not being seen simultaneously the number we can identify is
much smaller, maybe 10,000–20,000. It is often claimed that we
can only identify 64 shades in a grey scale. There is also a limit to
acuity. Acuity is best in the fovea, and considerably worse outside
this small area in the eye.
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Take a close look at a colour-television-image (from about an
arm’s length distance). In the very centre of the gaze you are able
to clearly see the small red, green and blue dots or bars (depend-
ing on the type) making up the television-image. This clear oval,
or circular area, between a dime and a quarter in size, is falling
on the foveae in your eyes. It will jump around as you move your
eyes over the image and make four to six eye fixations per second.
At normal television-viewing distance all the small dots
blend together and we may perceive the image as “rather good”
or even “good.” More pixels are needed to make a really good tel-
evision-image. The maximum resolution is the same as the dis-
tance between two cones in the retina with one non-activated and
“blind” cone in-between. This corresponds to some 200 pixels
per millimetre (5,000 pixels per inch) at normal reading dis-
tance. The necessary number and size of individual pixels will be
defined by: 1) Size of the object depicted. 2) Size of the image. 3)
Viewing distance. 4) Image content. 5) Actual material carrying
the image (film, glass, paper, etc.).
Changing the pixels
Moving/changing pixels in a picture enables us to create thou-
sands of new images. Computers process each variation as a new
picture. But a human viewer may regard these images as func-
tionally identical. Analogously, a text can be presented in many
different ways, with different typefaces and pitches, etc., with no
major effect on perception of the text’s content.
Normally an individual pixel is insignificant from a visual
language point of view. A surprisingly large number of pixels can
be deleted from an image. A pixel may be an important feature of
a basic graphic image element (a dot, a line, or an area) or of a
simple shape, thereby contributing to a visual sub-meaning or a
syntagm. So, we can delete, add, or shift information in an image
without drastically affecting perception of image contents. The
pixels that form borders or edges between different shapes are
more important to picture perception than other pixels. Since the
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brain fills in missing information and always strives to make the
best possible interpretation of a given stimulus, the deletion of
even some meaningful parts of a picture is also possible.
Pixels are always small in relation to the screen on which
they are displayed. The greater the number of pixels used by a
system for image formation in a given area, the greater the sys-
tem’s sharpness and resolution. Close viewing distances require
images to be divided into many small pixels. For long viewing
distances it is enough with fewer and larger pixels. Pixels really
vary in size, and they also represent very different parts of reality.
Some examples below will illustrate this.
Satellites
The first American Landsat satellite was sent up in 1972. Land-
sat-1 registered green, red and two bands near infrared. Pictures
cover 185 x 185 kilometres on earth. Each pixel represents
80 x 80 metres that are 6,400 square metres. Landsat-1 was a
great success and was followed by Landsat-2 in January 1975 and
by Landsat-3 in 1978. Since 1982, the Land sat-satellites produce
images with a resolution of 30 metres. Each pixel has been re-
duced to 900 square metres.
The European SPOT-satellite was launched into orbit in Feb-
ruary 1986. It delivers images with a resolution of 20 metres in
colour, and 10 metres in black and white. The pixels were re-
duced to 400 and 100 square metres respectively. Usually SPOT-
pictures depict 60 x 60 kilometres of the ground surface. Such a
black and white “scene” has got 6,000 lines with 6,000 pixels
each, a total of 36 million pixels. The Swedish Space Corporation
receives a quarter of a million SPOT-pictures every year. It is pos-
sible to produce several kinds of maps for use e.g. in agriculture
and forestry.
Certain military satellites, “spy-satellites,” are suggested to
produce pictures with a resolution of only a few decimetres. Then
it is possible to distinguish individual people for example on
board a ship. When a SPOT-scene and a photographic portrait of
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a person are printed with the same resolution as full pages in the
same book, a pixel in the first image represents a part of reality
that is one million times larger than the area represented by a
pixel in the second picture.
Russian soldiers
At the 1980 Olympic summer games in Moscow some 3,000 Rus-
sian soldiers used square textile fabrics in different colours and
produced several images. Here each soldier represented a pixel.
The image of Mischa, the Russian bear, became a symbol of the
Olympic games.
At the Olympic Games Moscow 1980 some 3,000 Russian sol-
diers used square textile fabrics in different colours and pro-
duced several images. This is picture is from the Opening Cere-
mony. Picture: Wikimedia.
The Jumbotron
The Jumbotron, the largest video-screen in the world was
25 x 40 metres, equivalent to a ten-storey building when it was
first presented at an exhibition in Japan in 1985. The Jumbotron-
image, which could be seen by more than 50,000 people at the
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same time, consisted of 150,000 picture elements. Each picture
element was an 8 x 4.5 cm TRINI-LITE cell with a blue, a green,
and a red section. A computer system was used to control all the
different pixels individually.
Mosaics
A mosaic has thousands of small pieces of glass or marble in dif-
ferent colours. Each piece is carefully put into a soft foundation
that then hardens. The large mosaics in the cathedral of St. Peter
in Rome, and in many other churches are seen as actual paint-
ings. We have to get really close to the images to see the individ-
ual pieces. We can see the small pieces of glass and marble as
pixels.
Analogue and digital coding
Whether data is stored with analogue codes (as continuous sig-
nals) or with digital codes (as sequences of discrete values, writ-
ten with binary ones and/or zeros) are of major importance. An-
alogue coding takes up much less space than digital coding. Video
data stored in analogue form is suitable, for example, for enter-
tainment when sequential viewing of a program from beginning
to end is desired.
The following examples illustrates the differences in needed
space between analogue and digital storage of data:
1. A single page of a book can hold about 2,500 characters (i.e.,
50 lines containing 50 characters, including spaces between
all the words).
2. Storing the same book page in digital form would require
20,000 bits of information. This may seem like a great deal
but it is still almost negligible compared to the storage and
transmission of data in other media.
The following examples illustrates the equivalent need for stor-
ing space in different kinds of representations in analogue, and
digital form:
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1. Storage of one ordinary line drawing is equivalent to storage
of five pages with text.
2. Storage of one second of FM radio is equivalent to storage of
ten pages with text.
3. Storage of one second of digital sound on a compact disc is
equivalent to storage of 35 pages with text.
4. Storage of one second of television is equivalent to storage of
250 pages with text.
5. Storage of one second of HDTV is equivalent to storage of
1,500 pages with text.
6. Storage of one frame (a scene) from the SPOT-satellite is
equivalent to storage of no less than 50,000 pages with text.
Thus, it is easy to see that digitally stored data always takes up
much more space than data stored in analogue form. However,
provided that the number of pixels is large enough, digitally
stored data offers numerous opportunities for easy and conven-
ient editing, and even “manipulation”, of images, text, and sound
in different ways. This may be highly important in different kinds
of interactive applications, such as multimedia systems for edu-
cation and training.
The editing of a written text can result in the production of a
message with fewer words. In speech synthesis, i.e., computer-
generated speech, the amount of transmitted data can sometimes
be reduced by 99% with no serious loss of message comprehen-
sion. However, here the aesthetic quality of speech may decline
considerably.
In a similar manner, the number of pixels in an image can be
reduced without any major impact on the image’s actual mes-
sage. Thus, it is possible to more effectively make use of com-
puter memory capacity. A bit-mapped image, created and stored
in a computer may be scaled. However, no new information is
added when the image is enlarged and important information is
lost when the image is reduced. Thus, it is normally best to create
an image in the correct size from the start.
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Computer images
Computer images are digital. In some systems the square or rec-
tangular pixel is either white (light) or black (dark). In other sys-
tems the pixels can be varied in a grey-scale and/or in a colour
range. The number of colours that can be reproduced depends on
which computer, which operating system, which program, and
which computer screen is used.
Quite often eight bits of information is used for red, green,
and blue colours, respectively, and eight bits for text and graph-
ical effects. Each colour can be stored in 256 levels. In total it is
possible to create 16 million nuances in an image. The individual
pixels are always very small compared to the screen. More pixels
within a given area provide more details and better sharpness in
the system. The individual pixels in large systems can actually be
much larger than the whole screens in smaller systems.
This main section includes the following sections: Creation
of computer images, and Computer screens.
Creation of computer images
Computers are capable of displaying many kinds of pictures on
their monitors. Rapid technological innovations constantly in-
crease the range of images displayable by computer. Computer-
displayable pictures are always converted to digital form at some
stage, i.e., a series of ones and zeros. Several very easy-to-use
drawing programs, charting programs, and even digital clip-art
files make it possible for anyone to create simple, but good-look-
ing graphics and other line drawings.
Pixel images
A pixel image, also called a bit-mapped image, consists of a large
number of small pixels, or picture elements, e.g., small squares.
These pixels have either a colour (usually black, but they may also
be e.g. green or blue, depending on the design of the screen) or
no colour at all. All pixels in an image have the same shape and
the same size. In “paint-programs” you have a lot of different
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painting tools. You can draw all kinds of figures in free hand and
you can easily change any individual pixel. Bit-mapped graphics
can be modified, stretched, condensed, inverted, rotated, and
outlined. Paint-programs are effective multi-purpose drawing
tools.
A number of “clip art” packages containing ready-to-use
drawings of people, buildings, cars, boats, tools, animals, plants,
etc., are available. Clip art programs are usually created in bit-
map technique. The drawings may easily be changed and modi-
fied to fit a special style. Like all other computer-images they can
be integrated with text.
In an image created in a computer with a low resolution (72
dots per inch) it is possible to see the individual pixels. In the
enlargement it is easy to see that each square pixel is either
black or white.
When a bit-mapped image is printed, the black pixels get the
colour of the print medium (usually black), and the white pixels
get the colour of the paper (usually white). The quality is defined
by the quality of the printer. The better the printer, the better the
technical quality of the printed picture. The relative distribution
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of printed and non-printed pixels builds the image. The more
pixels, the better the resolution. Normally the resolution is not at
all “good enough” to create a suitable picture. This is especially
true if we need to change the scale of a picture. Apart from lines
in vertical and horizontal positions, all other lines get a rugged
appearance. The image quality is the same when printed with a
laser printer or with an advanced phototypesetter.
Vector images
A vector image, or an object-oriented image, is based on mathe-
matical functions and is composed of lines and closed polygons.
A coordinate system holds all the information on where lines, cir-
cles, squares, rectangles, and other shapes start and stop. Shapes
can be filled with various patterns and delineated with different
lines. This means that an image can be scaled up and scaled down
without loss of any quality. The image is re-drawn according to
the specifications set by the new size.
This vector image is based on mathematical functions. It can be
enlarged and reduced in size without any loss of quality. In the
“NCS Colour Solid” yellow, red, blue, and green, are all located
on the circumference of the Colour Circle (here black). The Col-
our Triangle is any vertical sector running through half of the
NCS Colour Solid, such as e.g., white–blue–black–white, and
white–green–black–white.
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Computer systems are being used to an increasing degree for
editing, correcting, processing, retouching, and supplementing
the contents of pictures for books, magazines, or other printed
matter, and for slides and overhead transparencies. The basic
picture, such as a drawing or photograph, must be digitized with
the aid of a scanner or special video camera. The computer can
then feed the digitized images to some peripheral such as a laser
printer, dot matrix printer, plotter, film, or a printing plate.
A vector image can be scaled up and scaled down
without any loss of quality.
Hybrid pictures
The production of charts and graphs may be very time-consum-
ing. Several computer programs can convert traditional tabular
data to various kinds of graphics. These programs allow you to
enter all the values needed, into a spreadsheet-style grid. They
take the information, do all the calculations and present the re-
sults as line charts, bar charts, pie charts, scatter charts, and
combinations of those styles. Once data is entered you can usu-
ally choose from several different presentations. Using programs
combining the bit-map creates a hybrid picture and the object-
oriented programs.
Computer-generated pictures
The concept of computer-generated pictures, i.e., computer
graphics, is employed in many different ways. However, image
generation by computer is the common denominator.
Computer art
Computer art is a young art form comprising visual presentations
whose aesthetic aspect predominates. Computer art consists of
images created on an interactive basis and of images and patterns
generated at random. Computer art often contains animated se-
quences and is displayed at, e.g., exhibitions, art galleries, etc.
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Computer art can also be displayed on paper. Image information
is often stored pixel-by-pixel, and not as mathematical functions.
Information graphics
Information graphics may be divided into several subgroups.
Computer often generates business and news graphics. Sales,
stock, or production statistics are often illustrated with graphics.
If the values of individual variables are stored separately, the user
is often able to illustrate the information in different ways. His-
tograms, bar charts, pie charts, or curves are examples of availa-
ble options. The graphics are often reproduced on film (as a slide
or overhead transparency) or on paper. Graphics are being used
to an increasing degree for presenting information in research
and development.
In a discussion about the design of animated information
graphics Lowe (2019, p. 305) concluded:
Currently, the design of animations tends to rely heavily on
intuition and the application of understandings about what
techniques have proven effective in the realm of static
graphics. However, the prevailing design approach fails to
take proper account of the powerful influence that the dy-
namics of animations have on how viewers extract infor-
mation from the display and the essential role that infor-
mation extraction has on the development of understanding.
I really agree with this conclusion.
Design pictures
Design pictures comprise the subgroups of drawings, maps, and
patterns. Drawings, two-dimensional representations of mathe-
matical descriptions of objects, can be generated by various CAD
(computer-aided design) systems. The systems are often able to
“twist and turn” a depicted object to show it from different angles
before the object ever leaves the drawing board stage. Car parts,
ships, aircraft, machinery, buildings, etc., are examples of objects
being designed with the aid of CAD. CAD systems are often used
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in conjunction with CAM (computer-aided manufacturing) sys-
tems. Maps are successfully produced in CAD systems, combined
with vector systems. The systems make it easy to change both the
scales and contents of maps. Patterns, e.g., for textiles are also
produced in CAD systems. But these CAD systems can also be
used for producing patterns for, e.g., wallpaper, wrapping paper,
and book covers.
Entertainment graphics
Entertainment graphics such as electronic games and anima-
tions are also produced in computer systems. Many kinds of in-
teractive electronic games are on the market. Players manipulate
space ships, robots, heroes, and bandits in fantasy worlds. The
electronic games often feature dramatic colours, symbols,
changes in perspective, and sound effects. Developments move
at a furious pace. Only a few years ago, graphics were very prim-
itive, but their sophistication and resolution have been vastly im-
proved. Animation is becoming increasingly commonplace.
Computers are being used to create advanced animation effects
in movies, TV, and video.
Measurement pictures
Measurement pictures are representations of various measure-
ments in, e.g., medicine. Ultra-sonograms and CAT scans are ex-
amples of pictures employed for identifying differences in the
density of body tissues. The brain’s activity can be visualized and
measured with a positron camera. Measurement of thermal radi-
ation is another example.
Satellites with multispectral scanners continuously record
and transmit digital TV images of the Earth. These images are
analysed and used for many different purposes in meteorology,
geology, agriculture, and forestry. The interpretation of satellite
pictures is a widespread activity. Photographic pictures are also
used for a wide range of military applications.
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Computer screens
Computer screens can be constructed and manufactured in many
different ways and have very different characteristics. Examples
are fog screens, head up displays, light emitting diodes, liquid
crystals, magnetic field boards, picture tubes, and plasma
screens. Computers may also be connected to different kinds of
projection systems.
Fog screens
A fog screen is a technology that allows projection of images on a
screen in the air. This projection technology creates an illusion
that images are floating in mid-air.
A suspended device produces a thin wall of mist, a “dry” fog,
which is blown down between two curtains, or layers, of air
streams. The fog is produced from ordinary water and consists of
tiny water particles, a few microns in diameter.
Two video projectors can be used to project different images
on both sides of the screen. People can walk through the screen
with the images. Fog screen technology can be used for a large
number of applications.
Head up displays
A Head Up Display, HUD, is a special type of helmet used in ad-
vanced flight simulators and in Virtual Reality systems. Com-
puter generated images are projected by fibre optics onto the
curved visor in front of the pilot’s face. In the simulator the pilot
gets a flying experience that is suggested to be true to life. In sim-
pler simulator systems computer-graphics are projected onto
several screens, replacing the windows, or located just outside
the cockpit of the boat, car, or aircraft.
Light-emitting diodes
The picture area in LED-displays may be very large. The resolu-
tion is 6,400 pixels per m2. The pixels consist of red and green
light-emitting diodes with high efficiency, i.e., low power con-
sumption and long life. So far, no blue diodes have been
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developed. Screens with light-emitting diodes are used for adver-
tising. By turning the diodes on and off it is possible to create
simple animations, for example, text and simple graphics moving
across the screen.
Liquid crystals
Liquid crystals can be used for instrument displays or screens.
An LCD, Liquid Crystal Display, contains a liquid whose mole-
cules lie parallel when an electronic current pass through. Be-
tween polarizing filters, the crystals then look dark. The tech-
nique is common in, for example, wrist watches. Here every ele-
ment in the digits is connected so that it can be turned on and off.
In larger screens there is a net of crossing semi-conductors be-
hind the crystal layer. A dark dot appears in every crossing when
the current is turned on. A picture is built up quite slowly. A
FLCD, Ferro-electric Liquid Crystal Display, is a flat screen with
liquid crystals. The ferro-electric crystals work tens of thousands
of times faster than the normal LCD. They give better contrast
and use less energy.
Magnetic field boards
An electronic magnetic field board consists of small hexagons
containing a black magnetic material, like iron filings. Close-up
the board looks like a honeycomb. By using a magnetic head, a
“page” with text or images can be built up. The board is “erased”
by changing the magnetic field. It is also possible to write directly
on the board with either a magnetic pen or with markers of dif-
ferent colours.
Picture tubes
A picture tube, or a cathode ray tube, is the unit that produces
and shows the picture on a television-receiver, computer, or ter-
minal screen. The picture tube consists of an airless glass-tube.
Its rear end contains a device that emits electronic rays, while the
front part forms the screen. The back of the screen is illuminated
when hit by the electrons. A picture is built up by steering the ray
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over the screen. The additive combinations of a limited amount
of radiation can produce range of colours. The additive colour
combination starts in dark adding light to produce colour. The
size of the screen is measured diagonally in inches. A colour tel-
evision screen has a shadow mask with many apertures in it. A
computer screen has instead vertical slits that give better resolu-
tion and a more stable picture.
Plasma screens
Plasma screens are flat screens with a network of anodes and
cathodes. When the points are made live, a neon-like gas starts
glowing. Plasma screens are sharper but require more energy
than LCD-screens.
Graphical pictures
Single copies of graphical visuals can be hand-crafted using dif-
ferent techniques like drawing with a pencil, charcoal, crayons,
and pens; painting in water colours, acrylics, oils, etc. Multiple
copies of graphical visuals can be produced using technical
equipment for printing, print out, or copying. There are many
kinds of visuals and we can use several different criteria for clas-
sification. As far as production technology is concerned it is prac-
tical to distinguish between line-art or “full-tone pictures” and
“half-tone pictures” like photographs.
This main section includes the following sections: Full-tone
pictures, Half-tone pictures, Scanners, Printers, Printing, Elec-
tro-press, and Copying.
Full-tone pictures
Dots, lines, and areas of solid paint build up all line-art, or “full-
tone pictures.” Line drawings, schematic illustrations, maps, and
business graphics all belong to this category. Full-tone pictures
can be in black-and-white as well as in colour. When colour pic-
tures are printed we need one printing plate for each colour. To
be able to achieve this we have to produce one original for each
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colour. Thus, the picture is “manually” divided into its various
colour components.
This is a line drawing, with an enlargement to the right.
Half-tone pictures
To be able to reproduce the fine nuances of a photograph or fine
art the original must be divided into small picture elements. A
reproduction camera is used for photographical separation (an-
alogue technology). Here raster-screens are used to transfer the
original image into a raster-image. It is also possible to use a
scanner (digital technology) to create the raster-image. In the
scanner a light beam scans the complete picture area. The beam
“reads” all the nuances in small parts of the picture. This infor-
mation is converted to the raster-dots that are employed in the
printing of the picture. In both cases the number of raster-dots
will define the quality of the final printed image.
Black and white pictures
The photos we see in books and newspapers are really collections
of small dots. These printed dots vary in size within the fixed
“pixel-area” from nothing or a very small dot to gradually
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increasing dot-sizes, until the dot covers the complete “pixel-
area.” Smaller dots give the impression of light grey areas in the
image, and larger dots give the impression of darker tones. Thus,
it is possible to reproduce photos, drawings, and other originals
with (perceived) scales of grey. (Note that half-tone raster pat-
terns will only simulate grey. This is possible due to the imper-
fection of our vision. The only way to really achieve a grey hue is
to print the image with grey printing ink.)
A photograph (1) is read in a scanner e.g., with 100 lines per
inch. Then each registered “pixel-area” (2) gets a mean value
between 0 and 100% of, e.g., black. In the phototypesetter this
“grey level” is transformed to a raster-dot within the pixel-area
(3). The raster-dots can be created with a resolution of, e.g.,
1,200 lines per inch. In the printed picture (4) the individual
printed dots may be seen with the aid of a magnifying glass.
Examples of five “raster patterns” with increasing size of the in-
dividual printed raster dots (from less than 10%, left, to more
than 90% of black, right.)
In newspaper production, raster screens with a density of 50
to 65 lines per inch may be used in the pre-press process. For
book production, raster screens with a density of 100 to 133 lines,
or more, per inch may be used. Higher-quality printing allows
half-tone raster screens of up to 300 lines per inch, resulting in
2
4
3
1
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images with dots so small that you can hardly see them at all. The
films that are used to make printing plates may be produced us-
ing photo-typesetting machines, working with resolutions of 600
lines per inch for the newspaper plates and 1,200 lines per inch
for the book plates. An image, say a two by two-inch portrait, may
be printed with 10,000 dots in a newspaper and 40,000 dots in
a book. A large outdoor placard printed with low resolution may
be at least one thousand times larger than the same ad printed
with high resolution in a magazine. Both images may have an
equal number of pixels.
The raster pattern is easy to see in the enlargement.
Colour pictures
Images in colour have to be separated using different colour fil-
ters. This can be done photographically with a reproduction cam-
era (analogue technology) or electronically with a scanner (digi-
tal technology). Images in colour are separated into four different
half-tone films: blue, yellow, red, and black. A printing plate is
generated from each film. The picture is then printed in each col-
our, resulting in a “four-colour-process” visual.
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While we are looking at a picture printed in colour we expe-
rience a subtractive colour combination. The inks, dyes, and pig-
ments function like filters for the white light. The light is ab-
sorbed in different ways. When printing on white paper, yellow
and red ink produce orange. Blue and yellow create green. Red
and blue give purple. Yellow, red, and blue will become black.
However, since black ink is used for printing of the text, it is also
used for the printing of pictures. The black ink gives the picture
a distinct sharpness and more solid dark parts. To achieve the
best possible print quality the red colour that is used (magenta)
is somewhat violet, and the blue colour used (cyan) is somewhat
light. For the printing of black and white pictures, only one film
and one plate are needed.
The easiest way to understand printed dots is to examine a
printed picture. In a newspaper, the printed dots can be seen
with the aid of a magnifying glass. On outdoor advertisements,
and posters we can often see the individual printed dots even
without a magnifying glass if we look at it from a normal reading
distance.
Scanners
There are several types of scanners, from equipment designed for
amateurs to equipment for professional use. Desktop digitizers
and drum scanners will be mentioned here.
Desktop digitizers
Since photography includes a full spectrum of greys it is not pos-
sible for a computer, working in a bit-mapped mode, to represent
the shades of grey. It only shows black and white. There are dif-
ferent kinds of digitizers. A scanner allows the user to digitize all
kinds of illustrations on a paper. Desktop scanners work with
CCD-technology (Charge Coupled Device). A CCD-cell consists of
a number of light sensitive crystals that can transform light into
digital codes. Most desktop scanners work with 300 or 400 dots
per inch.
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The scanner can digitize an image either as a full-tone pic-
ture or as a half-tone picture. In full-tone pictures each pixel is
black or white. However, desktop systems are more or less only
at a halfway point in the reproduction of photographs and fine
arts. The low resolution of computer screens, scanners, and laser
printers, and the vast amount of storage that it takes to store a
high-resolution image electronically make digitized images pos-
sible only as low-quality simulations of photographs.
A laser printer with a resolution of 300 dots per inch uses
different half-tone matrixes. A four by four-pixel matrix gives a
print resolution of 75 dots per inch. Each matrix contains 16 pix-
els. Thus, there are 16 (or actually 17) different grades of tone on
each “print dot.” When the number of tones increases the resolu-
tion decreases. To get a satisfactory result at least 50–60 grades
of tone are needed.
The digitizing of half-tone pictures requires a lot of computer
memory. Each pixel is stored in a number of bits, representing
the grey scale. Four bits per pixel give 256 grades. In colour sep-
arations eight bits are needed for red, green and blue, e.g. 24 bits
per pixel. And a picture needs many thousands of pixels. In fact,
when the resolution is only 100 lines per inch one A4-page con-
sists of more than 5.8 million pixels. A black and white halftone
will need 35 million bits for 64 grades of grey. Only professional
printers can produce really good halftones.
It is possible to adapt the resolution to available printers, for
example to laser printers with 300 or 400 dots per inch, as well
as to photo type-setters with better print quality. The scanning
speed depends on the resolution and varies between 8 seconds
for 100 dots per inch and 62 seconds for 800 pixels per inch. A
hand-held scanner is moved slowly over an image on paper at an
even pace. The hand-scanner reads a ten-centimetre wide strip
at a time. The resolution is usually 400 dots per inch and 16 grey
levels. A graphic input tablet allows you to digitize an image by
tracing the lines on a drawing with a hand-held device like a
mouse.
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Professional scanners
Flatbed scanners or laser scanners are large scanners, with high
resolution, working with colour or black-and-white. Large sys-
tems for integrated image and text processing often contain a
drum-scanner. The original, a slide, or a print is fixed on a rotat-
ing drum. A laser beam reads the picture with a resolution of up
to 300 lines per inch creating up to 75 dots per inch for yellow,
cyan, magenta, and black, respectively. The digital image infor-
mation can then be processed in different ways. It is possible to
change the scale, crop the picture, and manipulate the contents.
It is, for example, possible to move picture elements, make cop-
ies, put in text or symbols, etc.
Printers
Several types of printers can print digital computer pictures. Sev-
eral types of printers can print digital computer pictures. Colour
bubble-jet printers, dot matrix printers, ink-jet printers, laser
printers, phototypesetters, plotters, telefax, telephoto, and ther-
mal printers will be mentioned here.
Colour Bubble-Jet Printers
In this printer, each of four high-density bubble-jet print heads
has 128 vertically arranged nozzles. With this printer digitally
stored images can be printed in full colour with a vertical and
horizontal resolution of 400 dots per inch. The maximum image
width is 472 mm. Plain paper, in 50 metre rolls, is used. It is pos-
sible to use four out of seven colours (black, red, green, blue, yel-
low, magenta, and cyan). In this system, all ink dots have the
same size.
However, the number of dots within an area can be altered.
Many dots create dark tones and few dots create light tones. Each
nozzle has a heater. When the heater operates the heat produces
small bubbles. Ink evaporates abruptly and the bubbles inflate.
After cooling, each bubble contracts. The ink splashes out of the
nozzle and the bubbles disappear. A colour bubble-jet printer can
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be used e.g. as a terminal for computer graphics, or for simula-
tions of colour plate making in the printing industry. The print
speed is 2,000 dots per second per nozzle. This means that
1,024,000 colour bubbles can be produced every second. A col-
our picture in A2 format is printed in 8 minutes.
Dot matrix printers
A dot matrix printer is an impact printer. It produces dot matrix
characters by pressing thin needle points, “needles” arranged in
a matrix pattern, 5 x 7, 7 x 7, or 7 x 9, to a carbon paper or a rib-
bon lying close to a paper. The needles form different characters,
letters, digits, or parts of a picture. Dot matrix printers work with
a resolution of 50-100 dots per inch. This is the same resolution
as that of many computer screens but considerably inferior to the
printout quality of laser printers.
Ink-jet printers
An ink-jet printer is an impact printer where the characters are
formed by an ink jet on normal office paper. The ink-jet printer
does not work with raster-dots but varies the number of inks
drops within a given area. Few drops give light colours. Many
drops give darker colours. The system is thus creating the same
kind of effect as the systems working with halftone pictures.
Many ink-jet printers work with pictures printed out with a res-
olution of 200-250 dots per inch.
Laser printers
A laser printer is an electrostatic device in which a laser beam is
scanned across the surface of an electrically charged selenium
coated drum. This is done with a rotating polygonal mirror. The
charge of the drum surface is modulated according to the dot ma-
trix character patterns. A whole page with text and images is built
up by a page description language (for example, PostScript) and
then transferred to a paper as in a conventional Xerographic
printer. Laser printers often have had a resolution of 300 or 400
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dots per inch. For these printers, it is hard to reproduce more
than a few grey levels.
When printing many grey levels, the dots get far too large
and the resolution too poor as they are built up by available
“dots.” However, 1,200 dots per inch horizontally and 600 dots
per inch vertically are enough for good reproduction of half-tone
pictures. Most laser printers have one toner that mainly consists
of black coal powder. There are also toners in blue, brown, green,
yellow, magenta, cyan, and red.
Phototypesetters
A phototypesetter usually works with high quality such as 1,250–
2,600 dots per inch. This is good enough to create very small and
close raster dots and to reproduce a great number of grey levels.
Printouts are made on photographic materials, paper, or film,
which are then used to produce printing plates. In order to get
really good half-tone pictures, the quality of a phototypesetter is
required.
Photographic copies
Photographic copies have the highest hard copy quality. The
chemical constitution of film and paper gives the limits for reso-
lution.
Plotters
A plotter works with one or more exchangeable pens that draw
lines, graphs, diagrams, drawings, or pictures in ink in several
colours directly on paper or film in different formats. The reso-
lution is normally 50-100 dots per inch. The highest known res-
olution produced by a plotter is 300 dots per inch. In a flatbed
plotter, the paper is placed on a plane surface. The prints can of-
ten be carried out in large formats. Professional graphic repro-
duction systems sometimes use so called laser plotters with the
possibility of exposing both film and plates in large formats and
high resolution, like 2,000 lines per inch.
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Telefax
The telefax is used to send text and image information via the
telephone network. The area of the paper is often divided into
approximately 2 million pixels: 50 dots per inch horizontally and
90-385 dots per inch vertically. The very best resolution divides
an A4-paper into 6 million pixels. It is common that telefax ma-
chines work thermally with heat sensitive paper in rolls of ap-
proximately 100 meters. There are, however, also fax machines
built on laser printers. Many telefax machines can be connected
to personal computers and then can be used both as scanners and
printers.
Thermal printers
Thermal printers print dot matrix characters. A font is equipped
with small needles. These point to an especially prepared, heat-
sensitive paper. The needles are heated in a pattern that corre-
sponds to the character to be printed, and the heat-sensitive pa-
per is affected. Thermal printers often have a resolution of 200
dots per inch. To create colour pictures, foils with yellow, ma-
genta, and cyan colour are used. By combining these foils, a great
number of colours can be produced. In desktop systems, the
number of colours is 256. In this system, the colour is heated over
to the image paper point by point. There are also thermal printers
that heat up small ampoules inside a special paper so that the
colour spreads inside the paper.
Telephoto
Telephoto or photo fax is a special kind of telefax equipment used
for sending and receiving pictures in a full grey scale. There is
also a system for colour pictures that transmits the pictures col-
our-separated. The transmission is done over the radio or the tel-
ephone network. Telephoto pictures are mostly used by news-pa-
pers and by some television stations. A thermal printer can be
used to print the pictures.
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Printing
Printing is the process of producing multiple copies of an original
using a printing press. A printing press consists of some means
for feeding the paper (or some other material) in contact with an
inked image carrier and a system for delivering of the copies.
There are four major categories of printing processes: 1) Relief
printing, 2) Intaglio, 3) Plano graphic processes, and 4) Screen-
printing. In all systems text and pictures are reversed in the
printing forms that transfer the printing ink onto the paper,
where it appears in the correct position.
Relief printing
In relief printing the printing areas are raised above the non-
printing areas, and the impression is made directly from the
inked raised surface to the paper. There are several relief printing
technologies: such as woodcut, wood engraving, letterpress, and
flexography.
Woodcut
The image is cut in a plate of wood, a wood block, which transfers
the printing ink to the paper. It is very hard to produce text in
small fonts on a plate of wood. The lines in the picture are often
rough. The woodcut is the oldest form of printmaking. It can be
traced back to ancient Egypt, Babylonia, and China, where
wooden stamps were used to make decorative patterns or sym-
bols in wax or clay. Blocks may have been used to print textiles
in India as early as 400 B.C. The oldest book, “The Diamond Su-
tra,” was block printed in 868 in China.
In Europe woodcuts were used for illustrating books as early
as 1460 and they became very important when the art of printing
expanded. During the 18th century artists in Japan produced
woodcuts in colour in a masterly way.
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Olaus Magnus, 1555, Book 5, Ch. 1. On Giants. This woodcut
shows three warriors in suits of armour. All three carry a
sword. The one in the middle has also a halberd and the one to
the right a mace. Most of the 471 woodcuts in the book are 59 x
93 millimeters (Dal, 1996, p. 3).
In linocut, the artist uses a plate of lino instead of a plate of
wood. Today graphic artists mainly use these methods as fine
arts techniques.
Wood engraving
In wood engraving, also called xylography, the artist engraves the
image in the cross-end of hard timber. This method was invented
in England 1775 and became very important for the production
of illustrated newspapers during the 19th century. To be able to
prolong the life of the wood engravings, casts in metal, stereo-
types, were produced during the middle of the 19th century. To-
day graphic artists mainly use this method as a fine arts tech-
nique.
Letterpress
In the letterpress process the image carriers can be cast-metal
type, etched-metal plates, or photopolymer plates on which the
image or printing areas are raised and the non-image areas are
below the surface of the printing areas. In the production of
books photo-engravings used to be very common for the printing
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of illustrations. Photoengraving was first done in 1824. The
screen principle was introduced in 1852. The first successful pro-
cess-colour engraving was done in 1893.
There are two kinds of photo-engravings: half-tone block
and line cut. A half-tone picture is photographed in a reproduc-
tion camera using a raster to create a raster-image. The raster-
image is copied to a photosensitive plate of zinc. The plate is
etched resulting in a relief. Prior to printing the plate is mounted
in the printing form. There are several kinds of letterpress print-
ing machines, both sheet-fed and web-fed presses. Presses in-
clude the platen press, the flatbed cylinder press, and the rotary
press.
Flexography
In flexography rubber or plastic plates on cylinders are used. Low
costs and solvent inks to speed ink drying are making inroads
into book printing, magazines, and even newspapers. Flexog-
raphy is being used extensively in heat-transfer printing for tex-
tiles. It is also a method for production of packaging materials,
labels, and wallpaper.
Intaglio
In intaglio (or gravure) the image areas are below the surface in
“ditches”. Ink is removed from the non-printing areas by using
the scraping action of a metal blade. There are several gravure
printing technologies, such as copperplate engraving, mezzotint
engraving, aquatint engraving, etching and gravure.
Copperplate engraving
In engravings, the image or design to be printed is cut directly
into a metal surface by the engraver. In copperplate engraving
the image is engraved in a plate of copper, which transfers the
printing ink to the paper. The line is very distinct and ends in a
fine point. The oldest copy of a copperplate engraving was
printed 1446, but it is supposed that the technology existed al-
ready a hundred years earlier. Copperplate engravings were first
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used for book production in 1476. During the 17th century cop-
perplate engraving became the most important method for pro-
duction of pictures in books. Today graphic artists mainly use
this method as a fine arts technique.
This is the copper engraving “Fortalitium Waxholm” included in
the book “Suecia antiqua et hodierna”. There are some large
warships of the type that were common in the middle of the 17th
century in the foreground of the picture, and the Waxholm de-
fensive castle. This picture was engraved in Paris 1670-1674 by
the engraver Adam Perelle, after a careful sketch by Erik Dahl-
berg. The format is 21 x 34 cm. Picture: National Library of
Sweden, 2017.
Copperplate engraving was once a widely used illustration
process, but it has generally been replaced by photoengraving.
Steel-die engraving is still used extensively for printing money,
stocks, postage stamps, and other kinds of high-quality prints.
Copper plates and steel-dies are produced manually, mechani-
cally, or photo-mechanically.
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Mezzotint engraving
In mezzotint engraving, the entire surface of the copperplate is
first covered with hundreds of small “pricks”. These are bur-
nished and scraped to create light areas. Mezzotint was invented
in the 17th century and it was used extensively until the early 19th
century. It was the only method by which the many nuances in
oil paintings could be reproduced with good quality. Mezzotint
engraving was the main method that graphic artists used as a
technique in fine arts.
Aquatint engraving
Aquatint engraving is a type of etching specially used for areas
with many shades and nuances. In tonal quality aquatint is sim-
ilar to the wash effect of a watercolour drawing. Aquatint is often
combined with other printing techniques, such as line etching.
The method has been known since the 17th century. Graphic art-
ists mainly use this method as a fine arts technique.
Etching
Etching is an intaglio printmaking process, originating in the 15th
century. All areas, dots and lines are incised into a metal plate
with acid. This is in order to later keep and transfer the ink to
paper.
A metal plate, made of copper, iron, or zinc, is cleaned and
polished. All imperfections and scratches must be removed from
the surface. An acid-resistant wax is applied to the entire surface
of the plate. With a needle the artist scratches the image into the
ground.
When the image is complete, the artist carefully submerge
the plate into a flat container with an acid. The acid bites the ex-
posed metal, and creates all the lines in the plate. After a while
the plate is removed from the container with acid, and then care-
fully cleaned.
Before printing the plate is “inked”. Then ink fills all the lines
in the plate. Any excess ink on top of the plate is carefully re-
moved. Ink remains only in the recessed lines.
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A dampened paper is placed over the plate. In the printing
press, the paper and the plate are squeezed together, and the im-
age is transferred to the paper. Later additional impressions can
be created and printed on the same paper.
In 1634 Rembrandt van Rijn (1606–1669) made this etching,
Woman Reading. The size of the motif is 10.7 x 9.9 cm. Rem-
brandt completely revolutionized the art form of etching. He in-
troduced a new innovation that made the medium more appeal-
ing to artists. Picture: Wikimedia.
In dry point etching the artist works in the copper plate with
a fine point tool. The line in dry point engraving is soft and fluffy.
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Some graphic artists mainly use dry point etching as a fine arts
technique.
Gravure
Gravure was first developed in 1875. The printing surface is di-
vided, by means of a screen, into a series of cells etched below the
plate surface. The surface may be treated in various ways to pro-
duce cells of varying size and depth. Sheet-fed and web-fed
presses may be used in gravure. Gravure printing gives good pic-
ture quality, but text is fluffy and ragged. Web-fed presses have
the plate wrapped around a cylinder and they can operate at high
speeds. They are called cylindrical, or rotary, presses. Such a
printing process is called rotogravure and is extensively used for
printing of weekly publications, catalogues, and brochures in
large runs.
Plano graphic processes
In a pantographic process, or lithography, the image and non-
image areas are on the same plane and are distinguished by mak-
ing use of the principle that grease and water do not mix. There
are two different pantographic printing processes: lithography
and offset lithography.
Lithography
Originally all lithographs were printed from a flat, lithographic
limestone on a flatbed press. The image is drawn on the flat sur-
face of the stone with a greasy crayon, an oily wash, or with India
ink. After a chemical treatment, the parts of the stone without the
image elements are susceptible to water. The printing ink is
transferred to the paper from the surface with the image.
The Austrian author Alois Senefelder invented lithography
in 1798, and it has been used for printing of lithographic art, but
also posters, placards, cards, advertisements, etc. As early as in
1858, Jules Chéret (1836-1932) created his first lithographic col-
oured poster in a characteristic, sweeping style (Hardy, 1986).
Ten years later, he returned to France after a seven-year-long
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stay in London, bringing modern English printing presses with
him. Chéret started a mass production of posters on a large scale.
Printing up to 10,000 posters per hour was realized, and at a very
low cost. Chéret drew his posters directly on lithographic stones.
By 1834 specially treated zinc plates began to replace the
heavy stones. The use of photomechanical metal plates in the
early 1900s made the technique of hand transferring from stones
obsolete. In the 1930s the deep-etch process was introduced. To-
day graphic artists mainly use the original method.
Offset lithography
In offset printing, text and images are copied to a photosensitive
plate of zinc, plastic, or paper. In plate-making the image area is
covered with ink that is grease-receptive, and the non-printing
areas are made water-receptive. The plate is mounted on a rotary
press. During the printing water and printing ink are supplied by
special rollers. The paper or other substrate picks up the impres-
sion of the image as the paper travels between the rubber-cov-
ered blanket cylinder and an impression cylinder. There are
many kinds of offset printing machines, from small office print-
ing machines to very large industrial printing machines. Sheet-
fed and web-fed presses may be used. In large offset printing ma-
chines, it is possible to print four colours directly in one com-
bined process. Today offset printing is very common for printing
of newspapers, books, and most kinds of graphical products.
Screen-printing
In screen-printing, or silk-screen-printing, the image is on a
screen stencil on silk, plastic, or metal through which ink is
forced to the paper. Screen-printing originated during the Mid-
dle Ages in the art of stencil printing of China and Japan. It was
practiced with great delicacy and intricacy. Until the 20th cen-
tury, screen-printing was a decorative and commercial medium,
used to enhance fabrics, wallpaper, furnishings, and advertising.
Screen-printing was introduced in the US about 1910.
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In screen-printing the printing form is a fine-meshed screen,
mounted over a frame. It was a hand process for many years,
used for making signs, banners, posters, and personal greeting
cards. In the 1950s techniques for making screen stencils photo
mechanically were developed. The pores of the mesh are blocked
by the stencil in the background or non-image areas and left open
in the areas to be printed. Ink is spread over the screen and
pushed through the open mesh areas with a rubber- or plastic-
bladed squeegee to produce a print.
Screen-printing can lay down the thickest ink film of any of
the printing processes. Screen-printing is used for printing on
paper, plastic, wood, metal, glass, foil, and textile fabrics. The
method is used for printing of posters, placards, and advertise-
ments of various kinds. Silk-screen-printing is also used for
many other industrial applications, e.g., for printing of electronic
circuit cards. Special equipment can be used for printing of labels
on bottles.
In serigraphy, the stencils are hand-cut by artists for the pro-
duction of screen prints as a fine art, serigraphs. In transfer
printing or decal printing the image is printed with silk-screen-
printing on a paper, which is then used to transfer the image to
T-shirts and other textiles.
Electro-press
In 1990, the Harris Graphics Corp invented Electro-press, a
method for printing, in the US. The system functions like a cop-
ying machine but it has “magnetic ink” instead of a coal-based
powder. This gives a better print quality. A computer gives im-
pulses to a number of diodes charging the drum. The charged ink
is attracted to parts of the drum and it is possible to print single
pages or sheets.
Copying
The development of copying machines in recent years has been
remarkable. Modern zoom optics in combination with microelec-
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tronics have given birth to small and handy copying machines
that automatically reduce and enlarge, retaining good quality.
Concurrent with simpler handling and better quality, the con-
sumption of copies increases. The Swedish public administration
produces about three billion copies each year. In average that
means 5,000 copies per public employee, which means approxi-
mately 25 copies per working day. The figure for the whole world
must be enormous.
Xerography
Xerography is a dry copying process. The text or image to be cop-
ied is projected onto a drum so that an electrostatic discharge is
conveyed where the drum is illuminated and stays where the im-
age is black. After that the charged (non-illuminated) surface at-
tracts an ink (colour) powder. This is transferred to the paper or
to the material onto which the image is to be transmitted. The ink
powder is fixed on and inside the paper by heat and pressure.
Colour laser copier
In a colour laser-copier a scanner “reads” the original picture and
converts it into digital signals. The scanning resolution is often
400 dots per inch. The scanner reads the image four times, for
magenta, yellow, cyan, and black. Then the digital information
about the image can be processed and transmitted to the laser
printer for production of colour copies. The picture elements
form 8 x 8-pixel raster-dots. Each pixel may be printed with ma-
genta, yellow, cyan, or black, or with combinations of those. In
this case the printed copies can have 64 gradations per colour. A
pixel can also be non-printed and thus have the colour of the pa-
per. Here the print resolution is 400 dots per inch. Since the im-
age is handled in digital form, it can be edited in many ways. For
example, the image may be reduced, enlarged, stretched, or
slanted. Individual colours can be changed. A projector can be
used for making full-colour copies from 35mm slides—even neg-
ative film can be used.
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Photography
When a light-sensitive surface on a photographic film in a cam-
era is exposed to light, it changes its chemical composition. The
polygon crystals of silver halogens are reduced to silver. When
the photographic emulsion is later chemically “developed” the
visible image is saved, either as a negative or as a positive image.
The many grains are only a few thousandths of a millimetre in
size, and they differ in shape. Different photographic materials
have different light sensitivity, and also different granularity. To-
day, there are photographic film materials available for many dif-
ferent purposes: from “normal daylight films” to films that are
sensitive to the infrared light, to X-rays, or to other radiations
that are invisible to us. Such special films are mostly used for sci-
ence research.
The resolution of a photographic film may vary from
500,000 to several million grains for each square inch. The the-
oretical upper limit is often put to 800 million grains for a square
inch of film. We can change the focal distance of the image by
changing lenses or by using a lens with changeable area. We can
aim a camera at a subject from many different angles. At a “low
angle” we see the subject from below. We see the subject from
above at a “high angle”. The subject is on the same level as the
camera at a “normal angle”. A telephoto lens includes a small sec-
tion of the subject. A wide-angle lens includes a large section of
the subject.
There are many different formats for still photography with
film cassettes, film discs, miniature film formats, standard 35-
mm film, and several larger film formats. All the individual
grains are irregular and they run into, and partly cover each
other. This is particularly true for photographic colour film
where the light-sensitive grains are formed and bound in differ-
ent layers. The film’s light-sensitive grains cannot really be com-
pared to all the regular pixels that are handled in digital cameras
and in computers.
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However, it is generally accepted that the granularity of a
slide with the “normal” standard 35-mm colour film corresponds
to a resolution of eight to nine million pixels. The resolution will
increase in films with higher sensibility. A colour slide may have
as many as 54 million pixels. A black-and-white slide may have
18 million pixels.
Apart from ordinary cameras there are several systems and
different equipment for producing slides. Both Polaroid and Ko-
dak have developed a series of hoods to be put in front of video
and computer screens to take photos with direct films. After a
minute or so the slide is ready to use. Many other systems work
essentially as reversed scanners. A laser beam exposes the film
dot by dot. The film is handled in a traditional camera body.
Several camera manufacturers have digital cameras that
store photographs on a small magnetic memory card. The photo-
graphs can be stored in a computer and printed.
In early 1973 the prominent Swedish photographer Lennart
Nilsson and I designed the exhibition Så börjar livet (How life
begins) for Moderna Museet in Stockholm. This picture shows
one wall in the large “Nilsson room.” Each mounted “Nilsson-
photo” had an explanatory caption. The small labels with cap-
tions are not visible in this picture.
Photography is commonly perceived as evidence of reality,
where the necessary, and therefore influential, human involve-
ment is so easily dismissed (Bock 2011). The size of any projected
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photograph depends on the size of the film-frame, the chemical
and physical quality of the film, the distance between the projec-
tor and the screen, and the focal distance of the lens.
Film
By showing a sequence of pictures describing a course of events
so quickly that the eye cannot discern the individual pictures, the
brain experiences movement. As early as the beginning of the
20th century, different toys with animated cartoons were experi-
enced as “live” by the amazed audience. Often film is recorded
and shown with 24 frames per second. Faster recording and pro-
jection give a more stable picture.
Film can also be projected with a different image frequency
than that with which it was recorded. Recording with high fre-
quency and projection with normal frequency results in slow mo-
tion. This is used for studies of fast or very fast and complicated
courses of events, for example, a bullet leaving a rifle. Recording
with low frequency and projection with normal frequency results
in the opposite–fast motion. This is used for studies of slow or
very slow courses of events, for example, a bud developing into a
flower.
There have been many different kinds of film formats. Ex-
amples are standard 8-mm film, S-8mm film, 16-mm film, 35-
mm film, and 70-mm film. Usually “standard film” refers to 35-
mm film for movie production. The height-width relationship of
this 35-mm film is 1:1.33. At the middle of the screen the resolu-
tion is some 450 dots per square inch. There are several types of
wide-film-formats such as Vistavision, CinemaScope, Cinerama,
UltraVision, IMAX, OMAX and Showscan.
Vistavision is a system for wide-film using standard 35-mm
film in a different height-width relationship. In America 1:1.66 is
used and in Europe 1:1.85. Vistavision has a resolution of c 150
pixels per square inch in the middle of the screen.
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CinemaScope is a system for wide-film first used in 1953. Cin-
emaScope uses a special camera in which the “anamorph” optics
“crowds” the image from the sides so that it fits onto a normal
35-mm film. When projecting the wide-film a special projector
“spreads out” the image again. The projected picture has the
height-width relationship of 1:2,35. The screen is slightly curved
to get the whole picture in focus. In the middle of the screen the
resolution is 200 pixels per square inch.
Cinerama is a system for wide-film first used in 1952. Cinerama
uses three separate 35-mm films simultaneously. Three different
cameras carefully put together record these. The films are pro-
jected on a wide, curved screen by three projectors. The viewers’
angle is 70-80 degrees compared to 40 degrees for 35-mm film.
Cinerama uses many speakers and stereo sound. In Disneyland a
screen completely surrounding the standing audience was used
for the first time in 1955. To start with eleven 16-mm film projec-
tors were used. Nine 35-mm film projectors later replaced these.
Simpler, semi-circular screens, “Cinema 180,” are now common
in amusement parks in many countries. Cinerama films often
show car hunts and dangerous rides in airplanes, helicopters,
boats, trains and the like. The result is often very suggestive. The
audience is easily carried away. The audio-visual stimulus is so
overwhelming that the balance system is greatly affected. It is not
unusual that spectators lose their balance and fall over. Audience
standing up reinforces the suggestive effect.
UltraVision used special cinemas, built between 1966 and
1974. UltraVision was projected on a curved screen, where 70-
mm film copied from 65-mm negatives was used. In the middle
of the screen the resolution is 625 pixels per square inch.
IMAX and OMAX are wide-films giving very large picture ar-
eas. The film-frames are put “lengthwise” on a 70-mm film and
not “crosswise” as on normal 35-mm film. OMAX or Omnimax is
shown inside a dome. IMAX is projected onto a large flat screen.
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Cinema-U, a modification of OMAX, has one of the world’s larg-
est cinema screens 23 x 16 m, 368 m2 (1:1.44) and was used by
the Japanese company Shueisha (Shogakan) at Tsukuba Expo
‘85. Here the film-frames were ten times as large as in normal 35-
mm film, which gives a very impressive quality. The enlargement
was 200,000 times. Another system with large high definition
pictures is Todd-AO-70.
Showscan also uses 70-mm film and is also projected on a
curved, very large screen, but is projected with 60 pictures per
second. The fast projection and the six-channel sound, makes it
possible to produce very realistic fast courses of events, like car
hunts, etc. As in IMAX and OMAX the audience sits high up in a
slanting auditorium, with a shorter distance to the screen. The
system is overwhelming also because of the large screen, which
goes all the way from the floor to the ceiling. At Expo ‘85 the
screen was 24 x 11 m, 264 m2. In the middle of the auditorium
the viewers have the ultimate angle of 75 degrees horizontally. It
is not possible to see the whole picture without turning one’s
head. It is possible to look straight ahead, up and down and to
the sides that is considerably much better then to look up as in
normal cinemas for standard 35-mm film. The resolution in
Showscan is ten times as good as in conventional television.
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Television and video
The word “television” comes from the Greek word téle, distant,
and from the Latin word vidére, to see. Television, or TV, is a tele
technical system for transmission of sound and images, stills, as
well as motion pictures in both black and white and colour. This
main section includes the following sections: Television systems,
TV receivers, and High definition television.
Television systems
In an analogue television camera, the rays of light are projected
from an image to an optical picture on a “picture plate” into the
camera tube. By optic-electrical conversion the light variations
are transformed into a low-frequency image signal, a so-called
video signal. A focused electron beam moving across the picture
according to a set pattern scans the image on the picture plate,
different brands working in different ways.
Usually the picture is divided into picture elements by the
electron beam moving in slightly inclined lines building up a so-
called television-raster. At transmission, the light information is
transmitted from one picture element at a time. These are pro-
jected reversed on the television-receiver’s picture tubes. The tel-
evision-image is of course built up, or “put together,” in the same
way as it was divided into picture elements earlier. The inertia of
the eye makes us perceive the different picture elements as indi-
vidual whole images or as motion pictures.
Most Western European countries have agreed on a colour
television-system called PAL, Phase Alteration Line. PAL is also
used in Australia and in several countries in Africa and in the
Middle East. 625 lines build up the television-image. Every line
consists of a large number of pixels. A colour television-receiver
has a “shadow mask” with some 400,000 small holes for red,
green, and blue, respectively. Our 50-periodical alternating cur-
rent is used to produce 50 half images per second. In one pass,
the electron gun of the television displays every odd-numbered
line of the image from top to bottom. In a following pass, the
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electron gun creates the even lines. Each pass takes 1/50 of a sec-
ond. This process is called interlacing. The two image halves “in-
terlace” and we see only one image.
A black and white television uses 450 effective lines with
each 560 pixels. Thus, a black and white television-image con-
sists of 235,200 pixels. Most video systems have considerably
worse resolution than broadcast-television. VHS has, for exam-
ple, usually 248 lines. Super VHS has an improved resolution of
400 lines.
In the US, Canada, and Japan a system called NTSC is used.
NTSC, National Television Standard Committee, is both the
name of the authority, which developed the American colour tel-
evision-system, and of the system itself. The NTSC is an analogue
system, which has been adapted over the years. First appearing
in black and white in the 40’s, then colour was added in 1953, and
finally, stereo audio was added in 1982. NTSC uses 525 lines of
resolution. In this system, 60 half images are produced every sec-
ond, and they are combined to 30 whole images per second.
France, Eastern Europe, the former Soviet Union, and Saudi
Arabia use SECAM, Sequential Couleur à Mémoire. SECAM is so
similar to PAL that it is possible to receive a SECAM-program in
a PAL television-receiver, but the colour signals are produced in
a different way. In a digital television or video camera there is a
CCD-plate with normally more than 400,000 pixels.
The aspect ratio of these television standards is 4:3. This was
a logical choice since that was the aspect ratio of movie film at
the time when television developed.
Television scholars are sensing a paradigmatic shift in the
production, distribution and consumption of content including
episodic programming (Christian, 2012) and news (Bondad-
Brown, Rice, and Pearce 2012).
There are several different systems for printing television
and video images on paper. Some video printers use thermal cop-
ying, others use plotters, and some employ ink-jet printers, or la-
ser printers.
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TV receivers
There are TV receivers in a number of sizes and types. The image
size is measured diagonally in inches. The most common sizes
are 18–27 inches for domestic use and 28–38 inches for public
use. Here are a few examples of less common TV receivers.
Wrist-TV
In Japan a wrist-television manufactured by Seiko has been sold
since 1985. The system consists of three parts: the actual wrist-
watch with a television-screen, a receiver to be carried in one’s
inner pocket, and a headset with an antenna. The image is cre-
ated by liquid crystals containing 32,000 pixels. The size of the
screen is only 17 x 25 mm.
Pocket-TV
In 1983 the Japanese company Matsushita in developed a com-
pact “pocket television” without a picture tube. The image is 2.4
inches diagonally and built up by liquid crystals. In August 1984
Seiko introduced a pocket colour-television. The image’s diago-
nal is 2 inches. The set weighs 450 g. The screen consists of a thin
film with a transistor in 52,800 individual pixels. The television-
image has 32,000 pixels. During 1989 Philips introduced a bat-
tery operated 3" colour-television. The screen is built on LCD-
technology and has 264 x 384, that is, 101,376 pixels.
Jumbotron
At Tsukuba Expo ’85 in Japan, Sony had built the world’s largest
video screen. It was 25 meters tall and 40 meters wide, i.e. 1,000
m2. The image was very bright and more than 50,000 people
could see themselves on the screen at the same time. The jumbo-
tron image had a 450,000-pixel resolution, comparable to stand-
ard-definition television sets at the time. The image on this Jum-
boTron was more than two million times larger than, for exam-
ple, a wrist-television.
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Multivision
Multivision or Video Wall is a display system where many televi-
sion-receivers (for example 16, 24, or 30) are put close together
forming a check pattern. All screens can show the same image,
different parts of the same image, or different images in varying
configurations. Multivision is used at, for example, shows, exhi-
bitions, and sometimes in department stores.
Third generation-television
VLSI (Very Large Scale Integration) chips control the image
quality in every individual television-set. The television-station’s
analogue signal is transformed to digital signals, and they can
then be processed in different ways. The image is cleared of shad-
ows and noise, and its definition is improved. The picture can be
zoomed in and “frozen.” It is possible to produce prints of any
still, simply by pressing the “print” button. A video printer pro-
duces the picture.
High definition television
The traditional PAL, NTSC, and SECAM television systems are
all analogue. Analogue waves cannot be compressed to carry
more data. In order to increase the quality of the image it is nec-
essary to use digital data. These formats are called high definition
television, HDTV. The aspect ratio of high definition television is
16:9. This ratio is similar to some current wide screen movies.
High definition television has a higher definition than to-
day’s analogue systems. There are a number of different formats
for high definition television. The television-image is built up by
1,125 lines in Hi-Vision, by 525 lines in the NTSC system, and 625
in PAL. Each line in Hi-Vision has 1,000 pixels. To manage the
high definition television-image’s closer line construction, the
bandwidth for each channel on the transmission side has to be
increased to about 30 MHz. For conventional television a band-
width of 6 MHz is sufficient. A capacity of 30 MB per second is
needed to handle moving high definition television-images in a
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computer system. The committee, which documented the devel-
opment of the digital standard, is called the Advanced Television
Systems Committee, ATSC.
To do full justice to a high definition television, television-
screens larger than normal, preferably one meter wide, are re-
quired. To be accepted by the normal consumer the television-
picture tube must then be made flat so that it can be hung on the
wall like a painting. Great research efforts have been made in re-
cent years to solve the problem of flat picture tubes. New tech-
niques like liquid crystals and plasma picture tubes are being
evaluated as well as new types of picture tubes and television-
projection systems using new technology. Experiments with high
definition television have been going on for a long time, with the
latest research (mainly in Japan) aimed at digital systems, rather
than the traditional analogue images.
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Classification of visuals
A visual has a content seen in the image. The visual is executed,
e.g., as a drawing. It is structured or executed, e.g., according to
shape and size. The visual has a physical form, a format, e.g., as
a 35 mm slide. The visual is used in a context, e.g., as an illustra-
tion in a textbook.
This chapter includes the following main sections: Classifi-
cation systems, The picture circle, Archives and image data-
bases, and Style.
Classification systems
Visuals can be classified according to various criteria, such as
sender, receiver, content, execution, context, and format, and
even according to criteria such as function, use, and the means of
production, etc. With reference to the distance to and size of the
motif, photographers may classify pictures as long shots, full-
length portraits, half-length portraits, and close-ups. In picture
archives, pictures may be stored, e.g., in accordance with content
categories. Doblin (1980) classified iconographic (visual) infor-
mation into three categories:
• Ideogrammatic visuals (symbols that attempt to convey a
single meaning, such as a road sign).
• Diagrammatic visuals (charts, graphs, and diagrams).
• Iso-grammatic visuals (photography, drawing, and drafting).
Hunter, Crismore, and Pearson (1987) presented a classification
as points along a continuum from realistic to abstract: photog-
raphy, artwork, diagrams and maps, graphics and formulae, ta-
bles and charts, orthography (icons). Dewar (1999, p. 286) di-
vided symbols into five main categories: 1) Industrial and occu-
pational (in the workplace). 2) Representing methods (machines,
instructions). 3) Management of public places (hospitals, muse-
ums, transportation). 4) Knowledge. 5) Particular activities (like
sports).
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Kędra (2016) classified images in the press in four photo-
genres: 1) Illustrative photography, 2) News photography, 3)
Portrait photography, and 4) Reportage photography. Important
criteria of photographs included their content, context, layout of
display, number of images, and their fulfillment of aesthetic, ex-
pressive, illustrative, impressive, informative, and marketing
functions.
Animations, charts, diagrams, graphs, illustrations, maps,
photographs, plans and sketches are important in engineering,
mathematics, sciences and technology. The traditional approach
to teaching of visuals is to classify them by purpose or by topic.
However, Carter (2013) classified static visuals into six categories
based on their properties. Some visuals may belong to more than
one category.
One-dimensional visuals. In this category visuals encode
data on a single axis. The axis may be oriented in any direction,
but it is often arranged horizontally or vertically. Examples are
analogue rulers, thermometers and time lines.
Two-dimensional visuals. In this category visuals encode
data on two or more axes. Examples are bar graphs, column
graphs and line graphs.
Map visuals. In this category visuals encode data through spa-
tial location of marks on an area. Examples are all kinds of maps,
blueprints and photographic enlargements and reductions.
Shape visuals. In this category visuals encode data in or on ge-
ometric shapes. Examples are geometric diagrams, geometric
solids and pie charts.
Connection visuals. In this category visuals connect two or
more nodes. Examples are electrical diagrams, flow charts and
tree diagrams.
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Picture visuals. In this category visuals often provide qualita-
tive information. Examples are drawings, photographs and
sketches.
According to Tversky (2017) empirical research can guide di-
agram design by uncovering cognitive design principles for cre-
ating marks and arranging them on a page. Like representational
art, illustrations, photos, and video, diagrams often include de-
pictions of objects, people, and scenes that are easily recognized.
Like texts, diagrams often include words, though typically not in
sentences. Tversky (2017, p. 350) used the following working def-
inition: “a diagram is an arrangement of marks on a virtual page
(stone, paper, or screen) that represents a set of ideas and their
relations.” With this definition diagram includes charts, graphs,
models, visualizations, and other graphic representations.
For Wileman (1993, p. 12) all representations of an object are
symbols. He showed a continuum ranging from concrete to ab-
stract. The first group, pictorial symbols, includes photographs
and drawings. Viewers should easily be able to translate a picto-
rial symbol to a real-world example. The second group, graphic
symbols, includes image-related graphics, concept-related
graphics, and arbitrary graphics. Image-related graphics can be
characterized as silhouettes or profiles of the object. Concept-re-
lated graphics look like the object but they have less detail than
image-related graphics. Arbitrary graphics are abstract symbols
for objects, constructed out of the designer’s imagination. The
third group, verbal symbols, is divided into two sub-groups, ver-
bal descriptions and nouns or labels. Only people who compre-
hend the language used to describe the objects can understand
verbal symbols.
However, in my view there seems to be no major difference
in “abstractness” between abstract arbitrary graphic symbols and
verbal symbols (Pettersson, 2002b). Thus, I prefer to distinguish
between two main categories of representations: I) Figurative
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representations, and II) Non-figurative representations. Each
category has two groups, and they both have sub-groups.
I. Figurative representations
Visuals
Three-dimensional images
Photographs
Drawings
Schematic pictures
Graphic symbols
Pictorial symbols
Abstract symbols
Arbitrary symbols
II. Non-figurative representations
Verbal symbols
Verbal descriptions
Nouns or labels
Letters or characters
Non-visual and non-verbal representations
Sounds
Odours and scents
Note that there are always many possibilities for classifica-
tion of images. However, one and the same visual can and will be
classified in different ways at the same time depending on the
specific criteria applied. Often the borders between different
groups partially overlap each other.
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The picture circle
The “picture circle” is an attempt to provide a simple graphic de-
scription of the relationship between types of pictures. This main
section includes the following sections: This is the picture circle,
Realistic pictures, Suggestive pictures, Symbols, Schematic pic-
tures, and Photographic portrayals.
This is the picture circle
The spot in the centre of the picture circle, the “bull’s eye,” rep-
resents scribble, which is the same all over the world and our first
attempt to make pictures. Increasingly advanced picture tech-
niques have evolved from scribbling. This development can be
represented with a series of concentric circles.
Scribble is followed by handcrafted visuals. Drawings with a
pencil, charcoal, crayons and pens; paintings in water colours,
acrylics, oils etc., various textiles, simple flip over moving pic-
tures, castings, models and sculptures of clay, plaster-of-Paris,
wood, metal are all examples. The borderline between hand
crafted and technically crafted visuals is indistinct. Some picture
techniques represent both handcrafted and technically crafted
methods. “Hand-made” prints, linocuts, etchings, lithographs,
serigraphs are examples.
This development is represented with a series of concentric
circles. Scribble is followed by handcrafted visuals. Drawings
with a pencil, charcoal, crayons and pens; paintings in water col-
ours, acrylics, oils, various textiles, simple flip over moving pic-
tures, castings, models and sculptures of clay, plaster-of-Paris,
wood, metal are all examples. The borderline between hand
crafted and technically crafted visuals is indistinct. Some picture
techniques represent both handcrafted and technically crafted
methods. “Hand-made” prints, linocuts, etchings, lithographs,
serigraphs are examples.
185
This is the “picture circle”. We have realistic pictures, suggestive
pictures, symbols, and schematic pictures. The border between
realistic and suggestive pictures is indistinct. Scribble (the red
spot) is followed by handcrafted visuals and technically crafted
visuals. Visuals that are used in materials for information or in-
struction are very often schematic and/or realistic pictures.
Hand-crafted visuals take a long time to make. They are per-
sonal, exist in individual copies, and reaches a narrow public.
Pictures made by children, for example, often display considera-
ble spontaneity and reveal a great deal about their personality,
degree of development, and maturity. In all handcrafted pictures
the relationship of information presented to reality is totally con-
trolled by the artist. Most photographic pictures, though, are of-
ten records of an event or object that actually existed.
Technically crafted visuals can be made in a relatively brief
period of time and easily reach a wide public. A TV camera can
take live pictures viewed simultaneously by millions of people in
different countries. In this way, we can “attend” various happen-
ings, such as sporting events, no matter where they occur. The
ease with which news pictures can be produced and distributed
may influence the selection of pictures. Sensational events, such
as a disaster, may be assigned a relatively large amount of space
in the mass media because pictures such as these attract wide-
spread interest. Here, the mass media bear an enormous respon-
sibility in their editing and selection of pictures.
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Realistic pictures
Pictures are always related in some way to reality. But they must
never be confused with reality and are incapable of replacing re-
ality. In some situations, people do actually confuse cyber-space
with reality. Objective documentation of a product, situation, or
course of events by means of documentary drawings, electronic
pictures, photographs, radiographs, satellite photographs, ther-
mographic pictures, ultra-sonograms and X-rays is often neces-
sary. These pictures are frequently realistic and simulate reality
in ways unique to each documentation process. However, appar-
ently objective documentation can occasionally be extremely
subjective and suggestive when the choice of images, the crop-
ping, layout, and caption contents are overtly selective. The ex-
pression “the camera never lies” can often be very wrong indeed!
Handcrafted pictures are now easy to reproduce in newspa-
pers, books, television, but the technical reproduction processes
do rob them of some of their original character. The halftone dots
of the printing process or the special characteristics of electronic
images are incapable of doing justice to, e.g., a painting made
with vivid colours and applied paint. This is even truer for sculp-
tures, dioramas, and other three-dimensional pictures. Holo-
grams, stereo, laser techniques and cyber-space may solve some
of these problems and re-create a realistic perception of the third
dimension. Current methods for making three-dimensional pic-
tures require considerable development.
Suggestive pictures
The borderline between realistic and suggestive pictures is indis-
tinct. Some visuals may be considered as suggestive pictures in
one context but as realistic pictures in another context. Ambigu-
ous pictures, which often express moods and emotions, are often
referred to as suggestive pictures. Even here the creators of the
pictures are out to influence the viewer in some way. Paintings
often belong to this category. It is often difficult and sometimes
impossible to make clear distinctions between different kinds of
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pictures. Advertising pictures, propaganda pictures, pictures for
information or instruction, or educational pictures can be both
ambiguous and unambiguous
Visuals that are used in materials for information or instruc-
tion are very often schematic and/or realistic. The role of such a
picture is to convey a given piece of factual information in the
simplest and most effective manner possible. But the picture may
also have the task of conveying moods, or of arousing the viewer’s
interest and involvement by disseminating certain information.
How we perceive a picture and the creator’s intentions de-
pend on the technical reproduction method and also on the man-
ner and presentation. We often need help and guidance in order
to interpret a picture’s message. Different captions or sound ef-
fects enable us to respond to one and the same picture in widely
differing ways. This is especially true of moving pictures. The rel-
ative size of the picture, cropping, lighting, and the location on
the cover of a book or newspaper page are also important to the
way in which the picture is perceived by people with differing val-
ues, feelings, attitudes, experiences, background knowledge, and
philosophy. Pictures often serve as amplifiers, i.e., the viewer of-
ten readily accepts information verifying his or her own opinion
on a given issue.
Symbols
Pictures that affect us in an unambiguous way can be referred to
as symbols. Signposts, traffic signs, labels, belong to this cate-
gory, representing objects or ideas. In specific areas symbols are
a supplement to all languages to help create better and faster un-
derstanding. Functional, instructive graphic symbols are actually
older than words. They are found in every culture however prim-
itive. In specific areas symbols are a supplement to languages to
help create better and faster understanding. Symbols have
evolved to the point of universal acceptance in such areas as mu-
sic, mathematics, and many branches of science.
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Some figurative graphic symbols are pictorial or represen-
tational (Pettersson, 1993). They are “image related” and simpli-
fied pictures. Pictorial symbols resemble the objects they repre-
sent. They can be characterized as silhouettes or profiles with no
surface detail. A traffic sign with a silhouette of a locomotive, to
denote a railroad crossing, is an example of a pictorial symbol.
In the design process, some pictorial symbols may be succes-
sively simplified into figurative and abstract graphic symbols.
They still look like the objects they represent but have less detail
than pictorial symbols. In athletic contests, like the Olympic
games, abstract graphic symbols are often used to denote the
sports. Good symbols are intuitive and we should be able to un-
derstand their meaning.
Some figurative symbols are arbitrary graphic symbols. They
are invented and constructed out of the designer’s imagination.
Usually arbitrary graphic symbols have no resemblance at all to
the objects or the ideas that they represent. Many are based on
geometric shapes. Many signposts and traffic signs are often
good examples of arbitrary symbols. They are unambiguous by
convention. We agree and decide on their meaning. Just as new
words have to be learned when we begin to study a new topic; we
have to learn arbitrary graphic symbols. Many non-figurative
verbal symbols, written characters, and letters of various alpha-
bets have evolved from simplified pictures. Verbal symbols are
used in written languages and in many branches of science. In
many areas, verbal symbols have reached universal acceptance.
Taking up only a very small amount of space, symbols can
convey a message containing a large amount of varying infor-
mation, equivalent to one or more sentences of text. Image per-
ception is very rapid, virtually “instantaneous.” Reading and
comprehending the equivalent message in words takes much
more time. So, symbols permit rapid reading. This is important
in numerous situations, e.g., in traffic, industry, and aviation.
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Schematic pictures
In many situations we need to use schematic pictures such as
blueprints, charts, engineering drawings, graphs, maps, etc.
Schematic pictures are representations of reality, but they are of-
ten non-iconic and may lack any resemblance with reality.
Classification of schematic pictures
There are several ways to classify schematic pictures. We can
study how schematic pictures are executed, how and when they
are used, and of what the content consists. The following pages
provide an attempt to classify schematic pictures with respect to
their type of illustration and their purpose.
1. Word visuals have words and/or figures and digits. There
are four basic groups of word visuals. 1) Headlines, lists, quick
facts, quotations. 2) Tables. 3) Word visuals with pictograms. 4)
Word visuals with pictures.
2. Graphs are pictorial representations of numerical data or a
geometric relationship between quantities. The graph of an equa-
tion shows pictorially the relation of independent variables to de-
pendent variables. When a variable y is a mathematical function
of another variable x, then the pictorial graph of that function will
represent the locus of all points (x, y) that satisfy the specific re-
lationship.
The line representing the relationship between or among
variables on a graph is called a curve, even when it is straight.
There are many kinds of graphs like single scales, and straight-
line graphs and multiple line graphs, coordinate grids, cumula-
tive and exponential curves, frequency and multiple frequency
polygons, histograms and multiple histograms, line graphs,
nomogram (with abac and alignment chart), normal curve, scat-
ter gram (scatter plot, scatter graph, or scatter plot graph), seg-
mented graphs (stacked curves, or stacked area graphs).
190
191
3. Diagrams show the relationships between various factors.
Diagrams need to be correct and simple. There are many kinds
of diagrams. In pictographs or isotype systems charts, each icon
represents a given quantity. A “time line” is a good example of a
simple line diagram. There are many bar charts, such as vertical
bar charts or column charts, horizontal bar charts, stacked bars,
segmented bars, clustered bars or multiple bars, overlapping
bars, high-low bars, high-low close bars, and enhanced high low
bars. Lengths are compared in pictorial length charts. Tri-linear
charts have three axes. Areas are compared in pictorial area
charts. Polygon charts have polygons. Circle charts have compar-
ison of areas.
There are several kinds of pie charts (or circle graphs), such
as basic pie charts, segmented (or exploded) pie charts, polar
area diagrams, wind rose charts, and ring chart of disk (or mul-
tilevel pie charts). Charts can have parallelepipeds, segmented
volumes, spheres, comparison of volumes, surface charts, picto-
rial characters in space, metro glyph charts. There are also bub-
ble charts, kite charts, block diagrams, four-field diagrams.
Quantity diagrams show totality and subsets. Tree diagrams
show organizational and hierarchical structures. Flow diagrams,
or flow charts, show how goods and people move. Web diagrams
are used for planning and production. Circulation diagram show
circulation. Circuit diagrams show circuits. Picto-diagrams have
simple pictures. Transportation diagrams show transportations.
192
193
194
Block diagram
Bubble chart
Kite chart
Surface chart
Pictorial characters
Metroglyph chart
Transport diagram
Pictodiagram
Circuit diagram
V
A
Four field diagram
a
b
c
d
Circulation diagram
Web diagram
195
4. Matrices are mathematical quantities consisting of rectan-
gular arrays of numbers. There are four-field matrices, multiple
field matrices, and complex matrices.
5. Plans show plans for various constructions and systems.
There are construction drawings, and floor plans and layouts.
6. Maps are heavily reduced flat images of the surface of the
earth. A map enables the user to see a generally complete repre-
sentation of the world at one time. Mapmaking, or cartography,
attempts to reproduce portions of the earth with a minimum of
distortion. The International Cartographic Association defined
cartography as “the discipline dealing with art, science and tech-
nology of making and using maps” (ICA, 2012). The information
contained in a map should be as accurate as possible. The scale
of a map is the relationship between a distance on the map and
the corresponding real distance.
Theoretically, an infinite variety of map types exists. Most of
the commonly used map types are either cultural or physical in
nature. Common types of maps are distributional maps, geologic
maps, soil maps, land-use maps, economic maps, zoological and
botanical maps, statistical maps, political maps, topographic
maps, meteorological maps, transportation maps, and historical
maps. Map projections can be placed in one of three general
groups, based on the method in which the information on the
round earth is transferred to the flat map. These are azimuthally,
conic and cylindrical projections. Common types of maps include
overview or location maps, detail maps, map with figures, cloro-
pleths, dot maps, isopleths, circle chart maps, pie chart maps, bar
chart maps, and flow maps.
196
197
7. Metaphorical pictures are used for something that has a
similarity with the actual image contents. Some examples are
concentric circles around a centre piece, pieces in a jigsaw puzzle,
spirals showing circular continuity, and staircase leading to a tar-
get.
8. Drawings may be created in many artistic styles. The pur-
pose of schematic drawings is basically to inform, not to deco-
rate. Schematic drawings must not be excessively imaginative or
unnecessarily abstract. Clarity is the most important factor. Im-
portant types of drawings are:
• Analytical drawings working in concert with photographs
• Cartoons
• Comic strip sequences
• Cross sections
• Cut-away drawings
• Diagrammatic renderings
• Exploded drawings
• Informative drawings, figures and objects
• Panoramas
• Silhouettes
• Sketches
• Stylized drawings
9. Integrating text and pictures with the use of captions,
headings, explanatory texts, and labels.
10. Integrating drawings and photographs makes it pos-
sible to combine the advantages from both categories. Photo-
graphs are documentary and drawings can be analytical.
Use of schematic pictures
Within one R&D-company most people created their own sche-
matic pictures in most of their documents (Pettersson, 1993).
The quality of the pictures reached from “very good” to “very
poor.” Several people designed their own graphic symbols, which
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they used in various combinations in their schematic illustra-
tions. A sample of documents used no less than 29 different sche-
matic pictures of telephones. Some of these pictures were well-
drawn schematic pictures, some were pictorial symbols, and
some were abstract symbols.
This variety of symbols and image elements used in sche-
matic pictures makes it hard for readers to understand the mes-
sages. The variety is often not aesthetically pleasing. It does not
aid comprehension; rather it introduces a lot of confusion. Tech-
nical documentation must be easy to comprehend. Thus, it is im-
portant to be consistent and to use the same symbols in different
schematic pictures.
Creation of schematic pictures
A “terminology council” was responsible for the development of
the new terminology that was needed in the company. Since sym-
bols can be regarded as “iconic or figurative representations of
concepts,” a set of carefully defined symbols was created as image
elements. These symbols were stored in digital form, and could
easily be accessed from all workstations in the network. We had
written “guidelines” to make it easier for people to create their
own schematic pictures.
The new images can be stored in a database and be used in
different documents, such as memos, instructions, reports, mag-
azines, and even books. Images can also be used in other media,
such as computers, OH-transparencies, slides, and multimedia.
Since the formats are different, images must be adopted for each
medium (Pettersson, 1993).
Using standard image elements and standard symbols in
schematic pictures is very cost-effective and makes it far easier
for all readers to understand the intended messages. The reada-
bility of schematic pictures is increased.
Descriptive visualisation
Martin (1989) defined technical illustration as (p. 6): “illustra-
tion of man-made materials, objects and constructions, possibly
199
including the situations in which they are used and the processes
and systems in which they are incorporated.” The main purpose
of a technical illustration is to describe or explain these objects
and constructions to a more or less non-technical audience. At
one end of a scale, the technical illustrator is asked to produce a
picture that is completely accurate, to the point where someone
can physically construct an object by reference to the technical
illustration. At the other end of the same scale the purpose of the
technical illustration is to provide a general impression of what a
specific object is or what it is used for in order to improve the
viewer’s understanding.
Descriptive visualisation of objects and systems has been an
important aspect of technological development since the begin-
ning of the industrial revolution. A technical illustration can al-
ways supplement a verbal explanation and may sometimes re-
place the words. Martin (1989) pointed out that clear visual in-
struction on individual components and their assembly sequence
was of crucial practical importance during World War II, when
technical illustrations enabled unskilled workers to play an effi-
cient part in manufacturing, replacing the trained workforce
which was depleted by conscription to the armed forces. Descrip-
tive visualisation of objects and systems are also used in medi-
cine and natural history, or scientific illustration. Another spe-
cialized subject area is architectural illustration.
Photographic portrayals
An analysis of a photographic portrayal can examine positive ver-
sus negative depictions of individuals in photographs (Archer et
al. 1983; Moriarty and Popovich, 1991; Moriarty and Garramone
1986; Wanta and Chang 2000). These authors have examined
several variables that will influence our perception of individuals
in photographs.
Camera angle. An individual appears powerful if he or she is
photographed from below with the photographer looking up at
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the subject. An individual appears less powerful if he or she is
photographed from above (Moriarty and Popovich, 1991).
Camera placement. Photographs showing a subject straight
on are more positive than those showing a subject from the side
and much more positive than those showing a person from be-
hind (Moriarty and Popovich, 1991).
Eyes. Individuals shown with closed eyes are viewed more neg-
atively than those shown with open eyes (Moriarty and Popovich,
1991).
Facial expression. Individuals smiling are viewed as positive
and individuals frowning are viewed as negative (Moriarty and
Popovich, 1991).
Framing. The larger a person’s face appears in a picture, the
more positively our perception of that individual is. A close-up
headshot of a person is more positive than a photo taken from a
distance (Archer et al., 1983).
Head position. Individuals looking straight at a camera look
more in control than those individuals looking up or to the side.
Individuals look least in control if they are looking down (Mori-
arty and Popovich, 1991).
Posture. Individuals are viewed more positively if they are
shown walking, running or moving. People standing are viewed
more positively than if they are motionless (Moriarty and Popo-
vich, 1991).
Purpose of photo. The purpose of a photo is important for our
perception of the person depicted (Moriarty and Garramone,
1986).
Secondary subjects. Other people in a photograph, the con-
text of the individual, may influence how people view a photo-
graph (Wanta and Chang, 2000).
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Archives and image databases
Pictures are now being created more rapidly than at any time in
history. Millions of pictures are produced every day. Sweden
alone (with a population of ten million) accounts for more than
200 million amateur photographs each year. And each of the
country’s 2,000 professional photographers produces a half mil-
lion photographs before retiring.
This main section includes the following sections: Collec-
tions and archives, Simple indexing, Systematic catalogues,
Large picture archives, and Indexing systems.
Collections and archives
Many pictures are put to active use in various ways. But a large
portion ends up in collections. Some collections evolve into ar-
chives. There are four main types of archives: 1) Personal, private
collections. 2) Commercial photo agencies. 3) (Personal) re-
search archives in different field. 4) Collections in museums and
other public institutions.
Greenwood (2011, p. 85) noted that the compartmentalized
nature of formal organizations might make it difficult for people
from different areas to collaborate and participate in decision-
making regarding photo archives.
The contents of an archive of photos can help explain how
others live, can illuminate the convictions of a community, and
can document processes and procedures. Barromi-Perlman
(2011) reported on the photo archives of a kibbutz in the north of
Israel. She observed (p 9.): “the photographs kept in the archive
seemed to have the potential of turning images into unshakable
myths in the eyes of the beholder.”
Bunn (2013) studied the archives at the Asheville Commu-
nity Theatre in the state of North Carolina, USA. She concluded
that a well-organized, thoughtfully managed photo archive is an
important part of an organization’s holdings. For a community-
based organization, like Asheville Community Theatre, the pho-
tographs in the archives reflect the participants and their
202
dedication to the art of theatre over the past seven decades. Ar-
chival photography is not only important in order to capture who
was in a production, but also serves to accurately reflect the pro-
duction’s design choices.
Simple indexing
Many photo collections are small enough to be accessed without
any special index. The owner knows the pictures and where they
are stored. This ease of access is no longer possible in large photo
archives holding hundreds of thousand or even millions of pho-
tographs. So, a large number of different indexing systems have
been devised.
Pictures may be indexed according to category, motif, or
subject. Era, geographic area, and persons may be other classifi-
cation concepts. Accession and negative indices and information
on the dates when photographs were taken and copyright may
also be provided. Commercial photo agencies often permit direct,
manual, and visual perusal of originals or copies in each category.
The feeling here is that the indexing or cataloguing of individual
photographs takes too long, costs too much, and conveys no de-
cisive advantages. Institutional photo archives, as used in re-
search and education, are often unable to manage without some
kind of cataloguing. Many indexing systems are based on hierar-
chic classification of picture subjects according to some pre-de-
termined code or on systematic catalogues in which every index
word has a corresponding alphabetical or alpha-numerical des-
ignation.
Systematic catalogues
The Inconclass system, developed in Holland, has a systematic
catalogue on theological subjects. The system is often used for
classifying artistic pictures. Each picture is assigned a classifica-
tion with a few index words. The method is based on a descrip-
tion of the picture’s main subject. Picture details and minor sub-
jects cannot be indexed.
203
Many museums use Outline, i.e. OCM (= Outline of Cultural
Materials), for classifying pictures. Outline was designed to be a
general classification and code system for social and cultural sub-
jects and operates with computerized routines. However, finding
codes (headings) that describe true picture contents is as hard
with Outline as with Iconclass. So, classification is influenced by
the perceptions of the individuals doing the coding. This makes
it difficult for a visitor to find pictures complying with her or his
requirements. Similar results have been obtained with many sys-
tems in other countries.
The Iconograhic Archives in Uppsala, in Sweden, employ a
system with a much finer “mesh.” Here, pictures with subjects in
the field of ethnology and cultural history (e.g. ethnographic or
folkloristic scenes) are recorded. The date a photograph was
taken, its country of origin and the source are recorded for each
picture. After an analysis of the picture contents, the main sub-
ject and minor subjects are then recorded according to a system-
atic code catalogue subdivided into subjects. The entry of search
conditions combined in different ways results in fast computer
extraction of information on whether the desired picture subject
is on file.
Large picture archives
APIS (Agency and Photographer Information System), devel-
oped in the Federal German Republic, is a computerized system
for managing picture archives and all the administration related
to the lending of pictures and selling of rights. A serial number,
heading number, a key word describing pictures contents, the
photographer’s name and the copyright holder are recorded for
each picture. This information is printed on a label that also
bears an optically legible bar code. The label is attached to the
back of prints or to mounts of transparencies. All captions are
stored in a database for full text searches. Desired photographic
subjects can be accessed very quickly.
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We can file photographs in numeric order or by subject
(heading). The latter system makes it possible to conduct man-
ual, traditional searches. The barcode is read with a light pen for
rapid entry of information on all pictures borrowed and re-
turned. The system also supplies invoicing, bookkeeping, statis-
tics, detailed reports to the photographer and other copyright
holders plus other administrative information.
Spectrum, the Dutch publisher of reference books, has de-
veloped an advanced system of databases for both text and pic-
ture administration (Thesaurus). The company indexed 45,000
illustrations, each accompanied by information on up to seven
parameters. These pictures have been published at 90,000 loca-
tions in different reference books, in various sizes, with different
cropping etc. The computer system contains all relevant infor-
mation on the illustrators/photographers, copyright, costs, dis-
bursements, archive locations of originals and films etc. The sys-
tem offers several different ways of searching for pictures by
means of search words. Spectrum experimented with models for
image classification.
An image classification system makes sense only if different
classifiers apply the same objective criteria to the image and sub-
sequently different picture researchers are able to locate the
same illustration. In a first experiment in 1979 twelve editors had
to classify 25 pictures by using catchwords. Results showed a cor-
relation as low as 0.2. In a following experiment a questionnaire
regarding categories combined with requests for description was
used. In this case the correlation was 0.67. In the final system,
1983, all indexing was made in the computer with a calculated
correlation of 0.80, which seems to be very good.
The development of WWW and Internet has opened new
possibilities for storage of huge collections of images. Each of the
stored documents can be quickly retrieved and displayed on a
screen or printed as hard copy if desired.
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Indexing systems
Image databases or image retrieval systems are computer-based
systems for searching and retrieving images from a large data-
base of digital images. Stanchev (1999) defined image databases
as, “a logically coherent collection of images with some inherent
meaning. The images usually belong to a specific application do-
main. An image database is designed, built, and populated with
images for a specific purpose and represents some aspects of the
real world.”
Image databases have many implications for society and are
used in a variety of applications such as: anatomy, astronomy,
automated catalogues in museums, biology, botany, computer
aided design, criminal identification systems, cultural heritage,
geographical information systems, geology, house furnishing de-
sign, industrial systems, manufacturing systems, medical image
management systems, mineralogy, and multimedia libraries.
Retrieval systems for first-generation image databases in-
cluded alphanumeric strings, full scripts, and keywords.
Metadata required manual input. However, manual input is
costly and there is always going to be a lack of coincidence be-
tween those who made the annotations and those who want to
retrieve images.
A large number of indexing systems have been devised to
guide access to individual images. However, real-life experience
shows that it is often very hard to find the intended image. We
know from several experiments that various subjects perceive
images in many different ways (Pettersson, 1985, 1986b, 1986c).
Even simple line drawings evoke many associations. Vogel, Dick-
son, and Lehman (1986) showed that image enhancement in-
tended to improve interpretation of image content sometimes
got in the way of the message. They concluded that image en-
hancement graphics should be used selectively and carefully.
When in doubt, they recommended, plain text should be used.
Limburg (1987) pointed out that receivers have even more
ambiguity or semantic diversity with visual images than with
206
most expressions of written language with its manifold mean-
ings. Lodding (1983) reported on the problems with misinterpre-
tations of icons used in computer systems. However, he con-
cluded that people find naturalness in dealing with images either
as an aid to or, in some circumstances, as the sole means of com-
municating.
A picture in a database can be sought with the aid of verbal
and visual indices. Each picture has a picture number as a head-
ing and a verbal description. The pictures can be listed systemat-
ically in numerical order in a numerical index. Or they can be
listed in alphabetical order (according to their headings) in an
alphabetical index.
Picture descriptions are stored in a free-text (or full-text) da-
tabase. Users access a picture via a number of different descrip-
tive terms. A verbal description of a picture should be rather
comprehensive. It may sometimes apply to an entire picture se-
ries. A database search based on certain descriptive terms could
produce several different pictures with the same description. All
such pictures would then be displayed in separate windows on
the terminal screen. Entry of a command causes full-screen dis-
play of any of the windowed pictures.
For children it might be easy to point with a finger at the
window on the screen. Pictures can be stored in files, stored in
other files in a kind of a tree structure. When a file containing
pictures is opened, the file contents are displayed in windows
that can be as small as 1.5 x 1.5 cm. Thus, verbal searches are used
on higher levels and visual, iconic searches on lower levels in the
storage structure. Users who know in which file a desired picture
is resident can go straight to that file. Index searches are em-
ployed when the whereabouts of a given picture is unknown.
Batley (1988) experimented with retrieval of pictorial infor-
mation from a database on a videodisc. The videodisc was cre-
ated specifically for the experiment. It contained 950 photo-
graphs selected from a collection of 40,000 photographs by a
Victorian photographer. The photographs were arranged into
207
broad subject groupings such as: Cathedrals, Castles, and Rivers.
A program in the authoring language Microtext provides access
to the database.
The program allows users to scan through images in the da-
tabase using a joystick (“serendipitous browsing”) step through
groups of related photographs (“specific browsing”) or type in
key-word descriptors (“key-word search”). Summary files keep a
record of each user’s interaction with the database. Users may
request text information about the photograph currently dis-
played on the screen and store a record of photographs they re-
trieve. The findings indicate that the search strategies adopted by
users are dependent upon two factors: the nature of the infor-
mation need and the individual user characteristics. Batley offers
three proposals for the design of visual information systems:
• Emphasis should be on providing a range of search options
for the user–to accommodate both narrowly defined and ex-
ploratory searching and to accommodate individual user
preferences.
• Care must be taken in the design of the user interface–the
emphasis should be on ease of use–so that the system is ac-
cessible to both naive and expert users.
• Some attempt should be made to individualize searching–by
allowing users the option of selecting their own range of scan-
ning speeds, choosing between menu selection and typing
commands, choosing which input devices to use, designing a
screen layout, etc.
In late 1980’s and early 1990’s retrieval systems were able to
compare image contents, based on colour, shape and texture
(Furt and Marques, 2002). These systems have very limited ca-
pabilities and are being employed in industrial robots pro-
grammed for taking certain components from a conveyer belt
and creating assemblies with other components. Developments
are most advanced in the military sector, e.g., in target-seeking
missiles capable of reading terrain and comparing readings to a
pre-programmed map and a predetermined route to the target
208
(e.g., the Tomahawk cruise missiles used in the Persian Gulf
War). But there is yet another major, unsolved problem, since
one and the same structure may occur in different pictures. Em-
pirical studies (Pettersson 1987) have shown that subjects given
a number of image elements combine them to form many differ-
ent picture contents. A lot of research on retrieval systems is still
needed.
Style
An illustration is a picture, complementing words. Illustrations
are printed in lexi-visual presentations. In audio-visual and
multi-visual presentations illustrations may have many other
formats. Illustrations are a “sub-set” of all visuals. Sloan (1971)
discussed four pictorial artistic styles, 1) Photographic, 2) Repre-
sentational, 2) Expressionistic, and 4) Cartoon. Photographic
style was defined as a coloured photograph of the subject. Rep-
resentational style was defined as an artist’s rendition of the sub-
ject that conforms to the subject in its true form. Expressionistic
style was defined as an artist’s rendition of the subject that leans
heavily towards abstraction. Cartoon style was defined as an an-
imated caricature of the subject. These four artistic styles form a
realistic to an abstract continuum.
Dondis (1973) discussed the anatomy of a visual message.
We express and receive visual messages on three levels: 1) Rep-
resentational, 2) Symbolical, and 3) Abstract. Representational
forms of illustrations are actual photographs of things. In sym-
bolical forms pictures show one thing and connote another. In
abstract forms illustrations provide minimal visual information
on the phenomenon illustrated.
In addition to size, shape, colour etc, the way pictures are
shot is important. The aesthetic value of a long shot is different
from that of a medium shot or close-up. According to Zettl (1990)
a scene can be presented: 1) Objectively (usually a long shot), 2)
Subjectively (usually a close-up), or 3) Creatively (created by the
medium itself, for example, superimposition, picture montage).
209
Metallinos (1990) has developed a schema that explains these
three forms of picture presentations in accordance with their
functional aesthetic value. We can: 1) Remain totally objective
and look at an event. 2) Become subjectively involved and look
into an event, and 3) Where the event is totally dependent on the
medium for its existence we can create an event.
An important difference between main categories of pictures
is the use of light. Pictures printed in books, magazines, papers,
other printed matter, and textiles, are seen in normal directed
lighting. In TV- and computer screens the light comes through
the image. Films, overhead transparencies, and slides are often
projected on a screen. It is important to study the difference in
nature of these groups of pictures. It is possible to classify pic-
tures according to their format. Depending on the execution il-
lustrations can be divided in three main categories: 1) Art work,
2) Photographs, and 3) Technically crafted visuals.
1. Artwork
Artwork is a metaphor, an abstraction, a manipulated and con-
structed image. It can look like reality, but it is always a repre-
sentation. Artwork abstracts, eliminates details, focus attention
and communicate fast. It consists of cartoons, line art, realistic
drawings, schematic drawings, stylized drawings, drawings of
animate objects, drawing of inanimate objects, exploded views,
X-ray drawing, blueprints, panorama drawings, paintings and
others. Throughout the history of civilizations, the language of
visual art has expressed the hidden concepts under the apparent
forms and the invisible deduced through the visible (Abdelfatah,
2022).
2. Photographic pictures
Photographic pictures are often quite realistic records of an event
or object that actually existed, like product photos, portraits, sit-
uation photos, landscapes. Photography has got a sense of reality
and a genuineness that makes it powerful. Most people believe
210
their eyes, and when they see photos it appears real to them. A
photograph can look like reality, but it is always a representation.
3. Technically crafted visuals
Technically crafted visuals may be charts (flow charts, organiza-
tional charts), diagrams (bar diagrams, linear diagrams, pie
charts, block diagrams, pictograms), maps (plotting maps, de-
tailed maps, figurative maps, cartograms), and scales (time
scales, distance scales, size scales). Technically crafted visuals are
also produced with TV cameras, thermographs, radiographs, ul-
tra-sonograms, ECG and EEG records.
211
Picture quality
There is no widely accepted definition for “picture quality,” nor
any unambiguous or sufficiently comprehensive measure of this
parameter. Any visual produced to convey information must ob-
viously contain the information to be conveyed. Such a visual’s
content, execution, context, and format elicit a response, a per-
ception, and possibly subsequent learning and memory. The in-
formation producer should produce representations in such a
way that perception, on the average, is optimized.
This chapter includes the following main sections: Measur-
ing picture properties, and Technical quality.
Measuring picture properties
Good picture quality can be defined as the degree of coincidence
between the sender’s and the receiver’s subjective perception of
the picture, and the reality (external or internal) represented by
the picture. According to this definition, the concept “picture
quality” is related to the entire communications process.
There are several ways of “measuring” picture properties.
These “tools” can be used before the original is finished, before
the technical production, and after the actual publication of the
images.
It is relatively easy to assess concrete image content. How-
ever, it is not at all as easy to measure aspects of abstract image
content. A subject matter can be depicted with many different
kinds of pictures and a single picture can be perceived in many
different ways. In order to be able to produce better information
materials we need to study the importance of various variables in
visual language. We need to further develop methods for meas-
uring picture properties.
This main section includes the following sections: Before the
original, Before technical production, and After publication.
212
Before the original
A picture description can be drawn up on the basis of our
knowledge of man’s ability to interpret and understand a visual
in terms of perception, contents, execution, context, and format.
A “picture description” is a depiction in words and sketches of a
visual that does not yet exist.
Before technical production
Draft versions and also alternative versions of information mate-
rials may be tested to determine whether or not the visuals are
attractive and appealing, communicate the intended information
or message, and are acceptable to the intended audience.
Ratings of OBS and reading value
Larssen and Skagert (1982) employed two “preview tests” in or-
der to assess reader response to as yet unpublished advertise-
ments. A simple interview test provides a good forecast of future
OBS (observation) and reading value ratings. The two central
questions were (p. 28): 1) If you encountered this ad in a news-
paper, would you stop to look at it? 2) If you encountered this ad
in a newspaper, do you think you would read any of the text in it?
When numerous subjects respond affirmatively, an ad can be ex-
pected to receive high OBS and reading value ratings. The oppo-
site is also the case, i.e., if numerous subjects respond negatively.
Utility/originality rectangle
The second preview test entailed assessment of ads according to
the concepts, “utility” and “originality.” First, the extent to which
the reader derived any benefit from reading or taking a closer
look at an ad was rated. The rating scale ranged from “no utility”
to “great utility.” The degree of execution originality was then as-
sessed. Readers usually subsequently rated ads that had been as-
sessed with positive originality and great utility (field 1 in the
“utility/originality rectangle”) were as “good ads.” Publication of
an ad with negative originality and little or no utility (field 4) is
virtually pointless.
213
Redundancy/Information
Berefelt (1976) suggested that experience grows in steps in the
power field lying between events previously observed and not ob-
served, between the familiar and unfamiliar, and between banal-
ity and originality. The greater the amount of information sup-
plied (the less the redundancy), the greater the amount of energy
needed by the information recipient in order to register and com-
prehend the new data. Berefelt used a horizontal line with maxi-
mum redundancy and maximum (new) information as the end
points to describe registration and processing of stimuli.
Maximum redundancy elicits complete familiarity with the
material, e.g., a picture. Maximum information elicits a total in-
ability to comprehend the signals. Our perception of different
pictures probably falls between these two extremes. Berefelt as-
signed seven proportionally spaced perception positions from an
infinite number of possible positions on the line. These percep-
tions, from a high degree of redundancy to a high degree of in-
formation, were referred to as “boring” (unpleasant), “neutral,”
“harmonious” (pretty), “fascinating” (nice), “interesting” (excit-
ing), “neutral,” and “irritating” (unpleasant).
A picture creator who is very familiar with her/his target
group can easily ensure that redundancy/information in a pic-
ture is on a level relevant to the picture’s aim. The redundancy
factor provides the picture creator with an opportunity to relate
viewer perceptions to picture contents.
The Legibility/reading value rectangle
A picture can also be rated according to legibility and reading
value. The legibility is mainly depending on the execution of the
picture. A visual is well worth reading and has a high reading
value when the content is interesting to the reader from a func-
tional and/or from a semantic point of view. Reading value is
very subjectively dependent on the reader’s degree of interest in
the message.
214
First, the extent to which the picture is readable for the in-
tended reader is rated. Does the picture have considerable read-
ing value and interest or does it have poor reading value and little
interest? The picture’s legibility is then rated. Is the picture dis-
tinct and easily read, or is it indistinct and difficult to read with a
view to its execution?
An informative picture with positive reading value and legi-
bility is probably “very good.” A picture is “good” if it is readable
but difficult to read. The picture is “bad” if it has limited reading
value and is easy to read but “very bad” when it has poor reading
value and is also difficult to read. Initial experiments suggest that
a preview test of this kind could prove to be very useful. The
BLIX-reading-scheme may be used in order to measure picture
readability.
After publication
A picture analysis, i.e., a descriptive rating of a picture, and vari-
ous practical tests can be carried out to determine whether or not
an information disseminator’s intentions are accurately realized.
The results of these tests can be used for revision of the picture
description that, in turn, later could result in even more effective
informative material.
A model for picture analysis
A picture analysis can comprise a detailed description of an im-
age. This description can answer questions related to the follow-
ing areas.
Visual language. Is the visual language clear and distinct? Is
the visual language adopted to the culture and to the intended
audience? Does the picture contain insignificant information?
Content. What is the message in the visual? Is the content easy
to read and understand for the intended audience? The readabil-
ity is mainly depending on the functional properties of the
215
picture. Is the picture likely to have an effect on attitudes, human
feelings, learning, or opinions?
Execution. Who is the picture creator? Is the visual a drawing,
a photograph, or some other kind of picture? Look at balance,
centres of interest, colour, composition, contrast, shape, size,
and technical quality. Does the picture have symbols and explan-
atory words? Is legibility good enough?
Context. What is the context for the picture? Is there a caption,
other pictures, sound, or texts in connection with the picture?
Format. For which medium, or media, is the picture produced?
Distribution. Why has the picture been produced? Has the pic-
ture been produced for advertising or for propaganda? How is
distribution organized? Copyright?
This analysis will identify the function as well as the quality of
the picture.
Picture readability
See the previous subsection Picture readability indexes in the
chapter Visual language for BLIX and PRI. The various preview
tests can also be transformed into true readability tests. The re-
sults of these tests can also lead to revised picture descriptions.
Goldsmith (1980, 1984, 1986) offered a model for analysis of il-
lustrations. Her model consists of twelve elements that are
formed by the interaction of four visual factors with three levels
of communication. The four visual factors are: 1) Unity, which
refers to a single image location. 2) Spatial relationships between
two or more images within a single picture emphasis. 3) Hierar-
chical relationships between images and text parallels. 4) Rela-
tionship between text and picture. The three levels of communi-
cation are: 1) Syntactic, which does not assume any recognition
or identification of images. 2) Semantic, which concerns the
basic recognition of an image. 3) Pragmatic, which reminds us
that readers will differ in age, sex, education, and so on.
216
This is the Goldsmith model for analysis of illustrations.
Visual
factors
Level of communication
Syntactic
Semantic
Pragmatic
Unity
An image ex-
ists, and the
bounds are dis-
cernible.
It is possible to
identify the im-
age.
Viewer charac-
teristics work
for or against
recognition of
the image.
Location
Depiction of
depth with the
use of converg-
ing lines.
Known size of
an object indi-
cate depth.
Viewer’s expe-
riences resolve
ambiguous de-
tails.
Empha-
sis
Cues attract
and direct
viewer’s atten-
tion.
The human
face attracts
attention.
Instructions
may influence
our perception
of the image.
Text
parallels
Physical/spa-
tial relation-
ship between
pictorial and
verbal signs.
Features iden-
tify an object
correctly. Im-
ages and words
are matched.
The interpreta-
tion of the mes-
sage by the
viewer.
Measuring concrete image content
The execution of a visual can be measured by objective as well as
by subjective methods. However, the image content may only be
assessed and measured by subjective means. Variables in visual
language have functional as well as suggestive properties (Pet-
tersson, 1989). The functional properties are related to cognitive
factual information in content, execution, context, and format.
The suggestive properties are related to emotions, conceptions,
aesthetic perception, tension, fright, etc.
Functional properties predominate in symbols. They are
also more important than suggestive properties in informative
217
and educational pictures since their task is to convey certain in-
formation in the most effective manner possible. The objective
for a picture for information may also be to convey certain emo-
tions and arouse the viewer’s interest and involvement (e.g., re-
garding conditions in other countries and cultures, or in past
times).
Suggestive properties are more important than functional
properties in “artistic pictures.” Art is not primarily a question of
objects. It is more a visual language for dissemination of ideas
and experiences that are difficult to put across in words. Irre-
spective of the sender’s intentions, different receivers may re-
spond in an emotional manner to a picture with mainly func-
tional properties. In the corresponding manner, some viewers
may respond unemotional and functional to pictures with pre-
dominantly suggestive properties.
In the USA more than 50,000 high school, college, and adult
learners have participated in more than 200 visual research stud-
ies. Dwyer has reported results from these studies several times
(1972, 1978, 1982-3, 1985, and 1994). Throughout these studies,
continuity was maintained by utilizing the same 2,000-word in-
structional unit on the human heart. Visuals range from simple
line drawings to realistic photographs, in black and white as well
as in colour. A variety of presentation formats, such as booklets,
television, and slide-audiotape presentations have been used in
these studies.
Pictures with concrete content have also been used in a num-
ber of other studies. In several experiments, subjects have been
given various assignments (Goldsmith 1984, 1986; Pettersson
1989, 1993). Subjects have been asked to name image content, to
describe image content, to index image content, to write cap-
tions, to assess image content, to create images, to complete a
story, to illustrate a story, to produce information sets, to pro-
duce information graphics and to describe picture context
Pictures that are easy to read are usually rated as aestheti-
cally pleasing and suitable for use in the dissemination of
218
concrete information (Pettersson, 1986a). Here, we often find a
close agreement between intended and perceived image content.
It is relatively easy to assess and measure concrete image con-
tent. However, it is never as easy to measure aspects of abstract
image content.
Measuring abstract image content
Russel (1991) studied how individuals make sense of their world
through photographs. A total of 163 children (11–12 years old)
were given black and white, and colour photographs and were
asked to write words and phrases which came to mind as they
viewed the images. The picture elicited more than 400 different
words/ phrases (associations). On average, each child gave a to-
tal of 17 words/phrases. Russel concluded that photographs
could provide a unique view of life, but the cultural environment
and background experiences of the viewer influence the meaning
in the mind of the viewer. In making sense of the world through
photographs each viewer internalizes the message to personal
space, time and life experiences.
Later Russel described five categories for viewer’s contribu-
tions to photographs (Russel, 1993). In observation the photo-
graph is seen as a series of observable elements. In interpretation
the photograph is seen as a stimulus for interpretation. Here the
viewer tries to create meaning from the visible elements. In per-
sonal memories the photograph is seen as a stimulus to recall
personal experiences. In participation the photograph is seen as
a stimulus for imaginative participation. The viewer is participat-
ing in the scene in the image. In medium intrusion the photo-
graph is seen as a specific communication medium related to the
photographer and to the camera.
Perceived image content
In one study the objective was to examine the degree to which
intended image content coincided with perceived image content
(Pettersson, 1985). Art students in Stockholm selected five ab-
stract concepts and produced five drawings and five photographs
219
for each topic. The pictures were all mounted on cardboard paper
in the A3 format (29.7 x 42.1 centimetres). The art students and
their teachers were called the “sender group” (46 persons). The
members of this group individually ranked all the pictures and
selected one drawing and one photograph to represent each
topic. Then they individually rated how well the content of each
picture corresponded to the picture’s intended content on a se-
mantic scale. The verbal ratings: very poor, rather poor, neither
poor nor good, rather good, and very good, were supplemented
with a numerical scale from zero to one hundred. In this scale
very poor is 10, rather poor is 30, neither poor nor good is 50,
rather good is 70, and very good is 90. It is possible to be better
than very good. This type of combined verbal and numerical scale
had been used in previous studies (e.g. Gabrielsson, Lindström,
and Elger 1983; Pettersson et al. 1984), since it makes statistical
analysis of verbal ratings possible.
Later representatives intended “receivers” (80 students) in-
dividually rated perceived image content of the pictures accord-
ing to the same semantic scale. The results showed that: 1) A sub-
ject matter can be depicted with many different kinds of pictures,
and that 2) A single picture can be perceived in many different
ways. There was poor agreement between the intended and the
perceived interpretations of these abstract image contents. The
drawings conveyed intended messages somewhat more success-
fully than the photographs.
The results also suggested that “qualitative” picture studies
must be undertaken with great care, since people perceive the
same picture in so many different ways. It seems that the only
way to assure that information conveyed by pictures is clear and
unambiguous is to provide a caption for each picture. In nine out
of ten cases, there was no difference in opinions between the fe-
male and male members of the sender group.
In a follow-up study, slides were made of the five drawings.
These slides were then projected to and rated by 113 adult sub-
jects at the UREX image laboratory in Finland. The subjects in
220
Finland rated the pictures very much the same as the subjects
had done in Sweden. The abstract image content was more im-
portant for the subjects than the format of the images.
Under-evaluation of pictures
Weidenmann (1989) studied under-evaluation of pictures. In an
experiment, 206 male students rated the “perceived quality” of
five materials on leadership. The five versions were: 1) Text. 2)
Text with “imagination instructions.” 3) Text with pictures and
no instructions. 4) Text with pictures and picture-oriented in-
structions. 5) Text with pictures and imagination instructions.
The “illustrated text with picture-oriented instructions-
group rated the material more positively with respect to four fac-
tors: 1) Comprehensibility, 2) Concreteness, 3) Attractiveness,
and 4) Memorability. The three groups with instructions in their
texts each rated the material lower in scientific “seriousness”
than did the two other groups. After two weeks 159 subjects re-
ceived a questionnaire concerning main ideas and details of the
text. Results showed that the “illustrated text with picture-ori-
ented instructions-group recalled significantly more main ideas
and details of the text than did all other groups. The differences
among the other four groups were statistically equivalent.
It can be concluded that an under-evaluation of pictures can
be compensated for by explicit picture-oriented instructions. In
materials for information and instruction (all) pictures need cap-
tions.
Image associations
In one study more than 300 subjects made 5 000 statements re-
garding nine photographs (Pettersson, 2001a). Results showed
that pictures generate a great variety of associations in audi-
ences. How we actually create meaning is an area where much
research still is needed. It was, however, concluded that: 1) Dif-
ferent assignments to a picture will influence the meaning in the
mind of the viewer. 2) Realistic photographs can generate a great
variety of associations in audiences. Visual experience is subject
221
to individual interpretation. 3) Humans, especially their faces,
are the kind of image content that will get maximum attention.
4) Quite often perceived image content is different from intended
image content.
In information design it is not sufficient merely to choose
and use good pictures. Pictures used in information and instruc-
tional materials always should have captions to guide the under-
standing of their intended content.
Means of production
The introduction of personal computers and different software
packages has changed the way many people work. This is true for
writing of text, and also true for the production of many kinds of
pictures. We can change the typography of text and thus adopt
the legibility of that text for different media and for different au-
diences. But how do people perceive text and pictures with dif-
ferent styles that are dependent on the means of production?
In one study 36 illustrator students selected one of six topics
(Pettersson, 2000). They made one traditionally hand-made pic-
ture in colour, and one computer generated picture and printed
it with a colour-printer. All pictures had a caption. These stu-
dents ranked all verbal and visual messages and thus selected
one to represent each topic. Later 47 intended “receivers” made
a total of 3,384 ratings. In this study the means of production
influenced the perception of the messages. Subjects seem to
“like” or “dislike” an information material. It was relatively easy
for subjects to assess concrete image content, but not abstract
image content. Females in the sender group and the female sub-
jects were in greater accord than the corresponding male groups.
Values and attitudes
Semantic differential scales, in which the sender and/or receivers
report how positively or negatively they respond to a given pic-
ture in overall terms or with respect to individual picture varia-
bles, can also be employed in measuring how “good” or “bad” a
picture is.
222
Semantic differential scales can measure a general attitude
toward pictures (Bad–Good), the aesthetic value (Ugly–Pretty),
the reading value (Uninteresting–Interesting), the technical
quality (Poor–Good), the legibility (Hard to read–Easy to read),
the expected educational value (Slight–Great), and the credibil-
ity (False–True). The combination of verbal and numerical scale
steps makes possible statistical calculations of mean values,
standard deviations, and confidence intervals. This makes the
method suitable for large groups of subjects.
Observations
Producers of visuals for information may benefit from observing
how receivers and “actual users” use information materials in
normal situations. Observers could also interview “members of
the audience” about how, why, and when they use visuals.
Visual analysis
In “visual analysis” the term “modality” means how real a repre-
sentation should be taken to be (Machin, 2007, p. 46). Photo-
graphs that bear a truthful witness to an event have got “high mo-
dality.” These images reflect what we would have seen had we
been there. Modality can be decreased or increased.
According to Machin (2007, p. 57) we can apply “modality
scales” to assess the “modality configuration” for an image. These
scales concern the degrees of articulation of background, colour
modulation, colour saturation, depth 1, depth 2, detail, light and
shadow, and tone.
1. Degrees of articulation of background. This is a scale ranging
from a blank background, via lightly sketched in- or out-of-
focus backgrounds, to maximally sharp and detailed back-
grounds.
2. Degrees of articulation of colour modulation. This is a scale
ranging from flat, un-modulated colour to the representation
of all the fine nuances of a given colour.
223
3. Degrees of articulation of colour saturation. This is a scale
ranging from black and to white to maximally saturated col-
ours.
4. Degrees of depth articulation 1. This is a scale ranging from
maximum depth articulation to simple overlapping of ob-
jects.
5. Degrees of depth articulation 2. This is a scale ranging from
the absence of any depth to maximally deep perception, with
other possibilities (e.g. simple overlapping) in between.
6. Degrees of articulation of detail. This is a scale ranging from
the simplest line drawing to the sharpest and most finely
grained photograph.
7. Degrees of articulation of light and shadow. This is a scale
ranging from zero articulation to the maximum number of
degrees of “depth” of shade, with other options in between.
8. Degrees of articulation of tone. This is a scale ranging from
just two shades of tonal gradation, black and white (or a light
and dark version of another colour), to maximum tonal gra-
dation.
Analysis of comic strips
Peterson (1984b) worked on an analysis of comic strips and pro-
posed the following model based on a semantic approach.
1. Storyline. Analyse the storyline. Which hidden values do the
figures represent? How are conflicts presented in the story?
How are conflicts resolved? Are any myths created? Which
attractive properties do the pictures have?
2. Structure and meaning. Analyse picture structure and mean-
ings on denotative and connotative levels.
3. Balloon texts. Analyse the importance of balloon texts.
4. Emphasis. Study location of emphasis in the communications
process.
This analysis will identify the function of the comic strip, e.g., to
be challenging or poetic. How is imagination employed? Is the
224
comic strip made in a compensatory, an emancipative, or a
power-confirmative manner?
Technical quality
Obviously, the technical quality of a visual should be “good” and
tailored to the specific medium. A printed picture should be
matte and distinct, not blurred, overly glossy, or dazzling. Reso-
lution should be sufficient for the reproduction of the desired de-
tails. Remember that fine details in the texture of a visual disap-
pear in the dot screen structure of the printed image. Even more
detail is lost in a television image, or on a computer visual dis-
play. Poor technical quality is far too common in information
materials. The result of most of the previous work on visualisa-
tion and making originals can easily be destroyed by a single er-
ror in the making of the master or in the actual production of the
copies.
225
ID Library
At the beginning of this millennium there was a huge lack of text-
books for the new academic discipline Information Design. At
that time, I wrote some research papers, and also some basic
texts about communication, design, and information. Already in
2002 John Benjamins Publishing Company published my book
Information Design, An introduction in Amsterdam and Phila-
delphia. This was useful, but it was not enough. Of course, also,
other people contributed with research papers, and after some
time also with textbooks.
Since I retired, 1 January 2009, I have continued working
with research at the Institute for Infology. I have developed an
Information Design Library with 12 e-books. These e-books in-
clude more than 4 000, and together they constitute my digital
Information Design Library, something I really wanted to have
for my own teaching many years ago.
• Message Design.
• ID Theories.
• Text Design.
• Image Design.
• Using Images.
• Reuse in Art and Design.
• Graphic Design.
• Cognition.
• Learning.
• Predecessors and Pioneers.
• It Depends.
• ID Concepts.
All these books are available at ResearchGate at:
< https://www.researchgate.net/profile/Rune_Pettersson >
226
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Appendix: Main concepts
Many concepts may have diffused and sometimes even multiple
meanings. For the purpose of this book I have used the following
brief descriptions of main concepts related to languages and text
design. Here these concepts are sorted in alphabetical order:
Abstraction is a simplification of existing shapes.
Achromatic colours are black and white. See Natural Colour
System.
Additive colour. In a picture tube the additive combinations
of the primary colours red, green, and blue lights (RGB) can pro-
duce a huge range of colours. The additive colour combination
starts in dark adding light to produce different colours. The end
result is white.
Advertising illustrations are images created for the purpose
of selling a product or a service.
Aerial perspective, atmospheric perspective. The air is never
absolutely clear. It is filled with greyish blue haze, moisture and
dust. This acts like a filter and makes distant objects seem ob-
scure and wrapped in mist and they are partly hidden. As a con-
sequence, objects viewed from a long distance seem indistinct
and pale. Many artists in the Netherlands followed Jan van Eyck
and used aerial perspective in their own paintings. Later Leo-
nardo da Vinci used aerial perspective in many of his paintings
such as the Mona Lisa.
Angular perspective, oblique perspective, two-point perspec-
tive, have lines that vanish in two directions to two different van-
ishing points.
Animation include different methods to make still pictures ap-
pear as moving images. Today, most animations are made with
computer-generated imagery.
241
Area-based positional perspectives include aerial perspec-
tive, colour perspective, tonal perspective, overlapping perspec-
tive, and shadow perspective.
Areas belong to the simplest components in visual language. An
area can be varied with respect to brightness, colour, colour com-
binations, context, emptiness, grain, grey scale, shaded or non-
shaded parts, shape, size, texture, and value. See Basic elements.
Atmospheric perspective, aerial perspective. When the dis-
tance to an object increases, the contrast decreases. As a conse-
quence, objects viewed from a long distance are indistinct and
pale. Many artists in the Netherlands followed Jan van Eyck and
used aerial perspective in their own paintings. Later Leonardo da
Vinci used aerial perspective in many of his paintings such as the
Mona Lisa.
Balance is the sum of all elements, the darks and lights, the hor-
izontals and verticals. A composition is balanced when the visual
weight of graphical elements on either side of the centre of bal-
ance are approximately equal. Balance can be formal or informal.
Formal balance has total symmetry and it is felt to be static and
harmonious. It may, however, also be boring.
Basic elements, or graphic elements, are dots, lines, areas,
and volumes. These elements can be varied and put together in
many ways. Basic elements are sometimes meaningful, some-
times not.
Biovisualisation, or biovisualization, is a visualisation of bio-
logical systems.
Bird’s-eye perspective, bird’s-eye view, is a level perspective.
Here an object is viewed from a high position. We may be looking
down from a vantage point in a high building, on a mountain, or
in an airplane. Sometimes the terms aerial view and aerial view-
point are used for bird’s-eye perspectives. The term aerial view
can refer to any view from a great height, even at a wide angle.
This is the opposite of a worm’s-eye perspective.
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Bit, Binary digit, is the most basic unit of digital information. A
bit can be expressed in only one of two states, 0 or 1, meaning is
on or off. It is yes or no. This is the only data a computer can
process. Eight bits are needed to store one character.
Bitmap is the set of bits representing the position of items form-
ing an image on a display screen.
Bitplane is a single bitmap, only one bit deep. It stores “zero or
one” in each pixel location to represent black or white.
Body language may account for up to half, or even more, of all
our communications with others. Many gestures and movements
can be interpreted without ambiguity in a given cultural commu-
nity, but not outside that community. Body language is partly in-
stinctive, partly imitative and learned.
Brightness is the experienced intensity of light (bright-dull). In
colour displays it is very difficult to distinguish brightness from
lightness (white-black). When the signal to a colour display is in-
creased, the brightness of the total screen is increased.
Brightness constancy is our tendency to judge the brightness
of objects to be constant, even though changes in illumination
make the objects appear brighter or darker.
Cartesian coordinates represent two-dimensional areas nu-
merically.
Central perspective, one-point perspective, or Renaissance
perspective is a Line perspective. In a central perspective, lines
in the picture converge at a common point of intersection–the
limit or main point–even though they are parallel in reality. Cen-
tral perspective is a “one-point perspective.” All lines vanish in a
single point in the picture. See Bird’s-eye perspective, Eye-level
perspective, Gentleman’s perspective, Line-based positional
perspectives, Military perspective and Worm’s-eye perspective.
Chroma, saturation, is the colour variation of the same tonal
brightness ranging from none to pure colour. In relation to hue
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it is a measure of the amount of grey, purity, or strength. At max-
imum chroma a colour contains no grey. Such colours are de-
scribed as bright, or vivid.
Chromatic colours are blue, green, red and yellow. See Natu-
ral Colour System.
Cinematography is art and science of motion-picture photog-
raphy, and filming either electronically by means of an image
sensor, or chemically by means of a light-sensitive material such
as film stock. Cinematographers use a lens to focus reflected
light from objects into a real image that is transferred to some
image sensor or light-sensitive material inside a movie camera.
Colour. When we talk about the colour of an object we usually
refer to the hue of that object. Most people are familiar with hue
through our labelling of colours such as red, orange, yellow,
green, blue and violet. There are strong cultural differences in in-
terpreting the meanings of colour.
Colour blindness is a condition in which certain colour dis-
tinctions cannot be made. This is more common among men
than women.
Colour circle is the circumference of the NCS Colour Solid. The
chromatic elementary colours yellow, red, blue, and green are all
located on the colour circle.
Colour coding is a good way to show that something is espe-
cially important and interesting. It can be used to improve atten-
tion in documents, in signs and in symbols and increase learning.
However, the number of colour codes must be limited and they
should always be explained. To avoid confusion and misunder-
standing, it is important that colour be used consistently. Incon-
sistent and improper use of colour can be distracting, fatiguing
and upsetting and it can actually produce negative results and
reduce learning.
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Colour constancy is our tendency to judge the colour of an ob-
ject as the same despite changes in distance, viewing angle, and
illumination. See Perceptual constancy.
Colour description systems describe colour in aesthetical,
physical, physiological, psychological and technical terms. Hue,
value and saturation describe what we see. Intensity, purity and
wavelength are physical dimensions. The relationship between
brightness, hue, lightness and saturation is very complicated. For
practical use in art and in industry several different systems
providing numerical indexes for colour have been developed.
Colour perspective. Colours gradually change from being
clear in the picture’s foreground into being blurred in its back-
ground. Warm-coloured objects appear closer to the viewer than
cool-coloured objects. A red or orange object against a green or
blue background will have a sense of depth.
Colour triangle is any vertical sector through half of the NCS
Colour Solid. It is used to describe the nuance of a colour.
Colour wheels are circular representations of the colour spec-
trum. Colour wheels are intended to explain the relationships be-
tween different colours. A colour wheel illustrates classification
of colours. It provides a reference to primary, secondary and ter-
tiary hues, and may help designers to successfully select func-
tional colour combinations.
Complementary hues are colours that are opposite one an-
other on a colour wheel.
Constancy is our tendency to judge colour, contrast, shape and
size as the same despite changes in distance, illumination, and
viewing angle. See Perceptual constancy.
Continuous tone art, such as illustrations and photographs
must be reproduced with halftone screens.
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Contrast constancy is our tendency to judge contrasts as the
same despite changes in distance, viewing angle, and illumina-
tion. See Perceptual constancy.
Cropping. An original picture can often be improved by removal
of irrelevant or distracting elements. Usually pictures can be
cropped a little bit from all sides. In practice, the photographer
always performs some “initial cropping” while taking the actual
photograph. When composing or taking a photograph, the pho-
tographer sets the boundaries or “frame” of the picture.
Cropping perspective, overlapping perspective, or playing-
card perspective. When certain objects are placed in front of
other objects this will enhance the impression of depth in a pic-
ture. The overlapping perspective was quite common in Euro-
pean mediaeval art.
Curvilinear perspective is a line perspective. It includes
Four-point perspective and Five-point perspective.
Dark values of colour with black pigment added are called
“shades” of the given hue name.
Data visualisation, or data visualization, dataviz, and DV, is
the creation of visual representations of data in a graphical or
pictorial format. Data are primarily, but not solely, numeric. The
main goal of data visualisation is its ability to communicate com-
plex data clearly and effectively. In many disciplines, it is viewed
as a modern equivalent of visual communication. See Infor-
mation visualisation.
Diagonal lines are unstable and attract the eye. They give the
impression of movement, creating visual stress. Artists may use
this implied motion when they wish to convey energy or action in
their works. Lines that reach out from one point in different di-
rections may be perceived as aggressive or violent.
Dots in visual language. A dot is the smallest graphic element
in visual language. The dot is usually a meaningless, or non-
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significant image element, such as one of many halftone dots, but
it could also be a syntagm, such as an eye in a cartoon-face. Or it
may even have a complete meaning, such as a ball in mid-air. It
all depends on the situation depicted. With respect to the tech-
nique and the different types of visuals, dots can vary in size,
shape, colour, value, grain, context, as well as position. Usually
single dots do not carry any meaning. It can also provide har-
mony or stress to a given composition.
DPI, dots per inch, measure the number of ink dots a printer can
deposit on a paper within an inch. For offset lithographic print-
ing, 300 dpi is standard.
Dropout is a halftone in which no dots fall on white areas.
Elementary colours are black, white, yellow, red, blue, and
green.
Emphasis is used to attract or direct attention or dramatize cer-
tain points within a visual. A dark dot in a light field, and a jog in
a straight line are two good examples of emphasis. These con-
trasts attract attention. Emphasis may also be used to direct at-
tention, and to keep attention, or dramatize certain points within
information materials.
Emphasis in pictures. Emphasis is used to attract or direct
attention or dramatize a certain point within a visual. Many dif-
ferent elements in a visual can cause emphasis. Such examples
are: Areas of colour, areas of shading, arrows, change in size, cir-
cles or ovals around objects, colour, colour against no colour,
complexity, detail against no detail, directionality, imbalance,
implied motion, isolation, letters in pictures, light against dark,
line drawings in photos, line intersections, lines, position or
placement of elements, reducing details, repetition, stars, tonal
contrast, variation out of context and words in pictures.
Emphasis in signs. Warning signs must have a high contrast
relative to their background. Informative words shall be used for
signals such as “Danger”; for descriptions of a hazard such as
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“Shallow water”; and for specific actions that should or should
not be performed, such as “No diving.”
EPS, Encapsulated PostScript, is a standard graphics file format
based on vectors, or object-oriented information.
Eye-level perspective, or normal perspective, is a level per-
spective. Objects are usually viewed straight from the front and
at the same level as the viewer. This “normal picture angle” and
the normal way of viewing is the least obtrusive angle.
Fals perspective, or imaginary perspective, was often used in
European architecture and pictorial art for the purpose of creat-
ing illusionistic effects. Some artists helped people to “fool the
eye.” This is the opposite of information design and instruction
design.
Fisheye perspective, or five-point perspective, has four van-
ishing points placed in a circle and one in the centre. This is the
curvilinear equivalent of a one-point perspective.
Five-point perspective, or fisheye perspective has four van-
ishing points placed in a circle and one in the centre. This is the
curvilinear equivalent of a one-point perspective.
Forced perspective is a line perspective. It is a form of optical
illusion. Forced perspective is used in architecture, film, photog-
raphy and video to manipulate human visual perception. It is
used to make an object appear to be larger or smaller, to be closer
or farther away than it actually is. Producers use scaled objects
and manipulate the correlation between them, the camera or
viewer and the vantage point.
Four-point perspective, or infinite-point perspective, uses
curving perspective lines to approximate the image on the curved
retina in the bottom of the human eye. It is the curvilinear variant
of a two-point perspective. A four-point perspective image be-
comes a panorama that can go to a 360-degree view and beyond.
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Gentleman’s perspective is a level perspective. It is higher
than the eye-level perspective but lower than the military per-
spective.
Geometrical perspective is related to the placement of ob-
jects within a picture. Objects close to the viewer are shown in
the lower part of the picture. Objects further away may be placed
on a vertical line, as steps on a ladder. This is sometimes called
vertical perspective.
Graphic elements. In computerized image processing graphic
elements can be defined in one of two systems: either mathemat-
ically as points and vectors, or in the form of pixels.
Halftone picture. To be able to reproduce the fine nuances of
a photograph or fine art the original must be divided into small
picture elements. A reproduction camera is used for photograph-
ical separation (analogue technology). Here raster-screens are
used to transfer the original image into a raster-image. It is also
possible to use a scanner (digital technology) to create the raster-
image. A picture needs a large number of pixels. In fact, when the
resolution is only 100 lines per inch one A4-page has more than
5.8 million pixels.
Hard copy is a printed copy of an image that is shown on a com-
puter screen.
HLS, Hue, Lightness, Saturation, is a colour model.
Horizontal lines are restful and relaxing. They create a strong
sense of equilibrium in any composition. Horizontal lines that
are parallel to the borders of the picture give the impression of
calm and stability. A horizontal line can serve, e.g., as a horizon,
a street, or a sea. Horizontal lines are perceived as being shorter
than equally long vertical lines.
Hue is the basic component of colour corresponding to different
wavelengths. Most people are familiar with hue through our la-
belling of colours such as yellow, orange, red, violet, blue, and
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green. In colour description systems hues are usually placed in a
band around a centre, in a colour-circle. Hue is expressed as a
value between 0 and 360 on the colour wheel. All of the colours
in the rainbow are hues in the visible spectrum of light. Changing
the hue values will dramatically alter the colour of an image.
ID. Today, the abbreviation ID has at least five different, but re-
lated meanings. In some contexts, ID means information design.
In other contexts, ID means instruction design, instructional de-
sign, interaction design, or interactive design. These different ar-
eas are related, but they are different regarding several important
aspects. It may sometimes actually be rather easy to misinterpret
the use of the abbreviation ID.
Illustration is a specialized area of art that uses images to make
an applied, visual presentation of a subject.
Image content. Variables related to image content are the de-
gree of realism, the amount of detail, objects, time, place, space,
events such as “action”, humour, drama, violence, etc., time dis-
placement, parallel action, metaphoric descriptions (symbolic
actions), the relevance and credibility of the contents, compari-
sons and statistics, motion, sounds such as speech, music, sound
effects and emotions. Some of these variables apply to moving
pictures in films or TV. Some apply to stills in printed media like
books, newspapers, etc. Others apply to both stills and moving
pictures. The contents of pictures can evoke highly positive or
negative responses in viewers, especially in children. Visual lan-
guage can affect our attitudes and emotions more easily than
speech and text.
Image context. A picture has both an internal and an external
context. I regard factors inside the medium as internal context or
inner context. In books, internal context is the interplay between
text and illustrations, the interplay between illustrations and lay-
out. Movies and TV programs have sound with speech, music and
sound effects plus visual and audio metaphors. Some computer
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programs contain advanced animation with interaction between
text, images and even sound. I regard the entire communications
situation, i.e., senders and their intentions for the picture and re-
ceivers and their circumstances (e.g., time available), as external
context.
Image design is the development and execution of visual mes-
sages. It is a powerful form of communication because visual
messages stimulate both intellectual and emotional responses–
they make us think as well as feel. Generally speaking it is not
possible to rank the different types of visuals. Often the type of
visual that should be used must be determined in each case with
a view to demands on the picture and the prevailing budget
framework.
Image execution. Variables related to an image’s graphic exe-
cution are image factors and image components. Examples are
colour (hue, value, saturation), shape (external shape, external
contour), and size (image, subject, depth).
Image format. The choice of format is of major importance to
our perception of image contents. Our perception of a picture
(such as a photograph) changes when we view it as a paper print,
transparency projected on a white screen, as a computer image.
Image framing. A frame or a box around an image, or some-
times around an illustration and text, may have different func-
tions. Image framing can be functional and/or attentional. A
frame will separate the image from the surrounding context and
draw special attention to information within the frame. In a
newspaper, framing is a way of helping the readers to combine
the corresponding text and pictures on the page.
Image functions–communication. According to research-
ers in the areas of instructional message design, visual literacy
and visual communication the most common opinions on func-
tions of visuals concern attention. Researchers mention attract,
gain, get, hold and maintain attention. Other common explana-
251
tory verbs are: facilitate, provide, persuade, create (an interest
in), illustrate, clarify, motivate, present and reinforce infor-
mation (to someone).
Image functions–information design. In information de-
sign the most common purposes of pictures are to: visualize,
clarify, inform, attract attention, facilitate reading, explain and
convey information. The type of visual to be used in the produc-
tion of materials for information and learning must often be de-
termined in each case with a view to specific demands on the vis-
ual and also to the prevailing budget framework.
Image functions–learning. The most common purposes of
pictures in the school environment are to: show, explain, visual-
ize, illustrate, clarify, inform, summarize, convey, mediate, elu-
cidate, present and give (perceptions), instruct, describe and en-
tertain. There seem to be different “fashions” in teaching practice
that differ from culture to culture and can change over time
within different cultures. Fashion in the use of educational media
is partly related to the technology that is available in that specific
culture at that time.
Image manipulation implies the improper control of people’s
perception of a given reality through the use of pictures. The eth-
ical rules for the press, radio and television clearly warn against
manipulation or falsification of picture content through mislead-
ing captions, odd montage, or suspicious trimming.
Image variables can be subdivided into four main categories:
1) Content, 2) Execution, 3) Context, and 4) Format.
Imaginary perspective, or false perspective, was often used
in European architecture and pictorial art for the purpose of cre-
ating illusionistic effects. Some artists helped people to “fool the
eye.” This is the opposite of information design and instruction
design.
Infinite-point perspective, or four-point perspective, uses
curving perspective lines to approximate the image on the curved
252
retina in the bottom of the human eye. It is the curvilinear variant
of a two-point perspective. A four-point perspective image be-
comes a panorama that can go to a 360-degree view and beyond.
Infographics, visualisation of complex data using graphics, im-
ages, symbols, and texts.
Information design comprises analysis, planning, presenta-
tion and understanding of a message, its content, language and
form. The main objective is to provide information needed by the
receivers in order to perform specific tasks. Information design
is a process (verb) as well as a result (noun) of that process.
Information literacy has been defined as the ability to access,
evaluate and use information from a variety of sources. There
are, however, many definitions of information literacy. An infor-
mation-literate person must be able to recognize when infor-
mation is needed and have the ability to locate, evaluate and use
effectively the needed information.
Information visualisation, or information visualization, is is
1) a graphical representation that clearly conveys complicated
data or ideas, and 2) the process of creating that graphical
representation. See Data visualisation, Visualisation.
Inner context. See Image context.
Intensity is brightness or saturation of a colour. The intensity is
decreased by the addition of grey, or a complement.
Inner context is an internal context. In a book it is the relation-
ship between various text elements, pictures and layout. We may
also discuss the relationships between the image elements within
a single picture. When we view a film or a television program our
attention is either on the image or on the sound. We may not be
able to attend to more than one stimulus at a time.
Internal context. See Image context.
Italic, italics, italic print, italic type, italic typefaces are mem-
bers of a family of type in which letters slant to the right with an
253
angle between 7 and 20 degrees. Italics complement the normal
vertical design. Italics is read more slowly than regular type.
Some readers dislike italics.
JPEG, Joint Photographic Experts Group, is a data compression
file format. It discards parts of the data and creates small com-
pressed files.
Legibility of pictures. A message has good legibility if it is easy
to read, and if the reader can easily see and distinguish all differ-
ent parts of the message.
Level perspectives. Starting from the highest level these per-
spectives are called bird’s-eye perspective, military perspective,
gentleman’s perspective, eye-level perspective, and worm’s-eye
perspective.
Light values of colour with white pigment added are called
“tints” of the hue name.
Line. A line may vary with respect to its starting point, its bright-
ness, colour, context, curvature, direction, evenness, grain,
length, orientation, positions of change, printing, shape, thick-
ness, value, and terminus. Lines can direct attention to specific
picture elements.
Line art is a black and white copy, without any variations in
value. Thus, line art is suitable for reproductions without half-
tone screens. Line art images may restrict visual impressions to
the essential information.
Line perspectives. In a line perspective, or linear perspective,
objects are conceived as being placed behind a picture plane onto
which straight beams of light are projected. All line perspectives
are based on the idea that an object appears to grow larger in size
as the distance between it and the observer decreases and vice
versa get smaller in size as the distance between it and the ob-
server increases.
254
Linear perspective uses the principle that parallel lines seem
to converge or meet at a distant point.
LPI, Lines Per Inch, measure the number of cells in a halftone
grid that are used to convert continuous tone images (e.g. photo-
graphs) into halftone dots for printing.
Military perspective is a level perspective. It is higher than the
Gentleman’s perspective and used in several historical paintings
of troops and battles. This perspective is perfect to see the differ-
ent groups of soldiers on the battlefield.
Motion graphics are animations or digital segments which cre-
ate the illusion of motion. Any kind of abstract animation can be
called motion graphics.
Moving pictures can be affective and provide readers with en-
tertainment and reinforce an experience both positively and neg-
atively. They can trigger associations and influence emotions and
attitudes.
Multi-view-perspectives show different views at the same
time. The pictures show objects as they are known to be rather
than as they are seen to be. In many Egyptian paintings, the head
and legs of a person are shown in profile, while the eye and torso
are shown frontally.
Natural Colour System, NCS, is a colour description system.
We perceive six colours as “pure.” Black and white are achro-
matic colours. Yellow, red, blue, and green are chromatic colours.
Every possible colour can be described with a specific location in
a three-dimensional model, a twin cone, called the “NCS Colour
Solid.”
NCS. See Natural Colour System.
Negative space or passive space in a visual is the part that is
not filled with picture elements. The negative space is usually the
background. Active space or positive space in a visual is the part
representing different objects. Space has no meaning in itself,
255
but it may be used to separate or bring together different picture
elements. In typography the shape of the space within an open
character, such as an upper case C is called a negative space.
Object-oriented image, or vector image, is based on mathe-
matical functions and is composed of lines and closed polygons.
A coordinate system holds all the information on where lines, cir-
cles, squares, rectangles and other shapes start and stop. Shapes
can be filled with various patterns and delineated with different
lines. This means that an image can be scaled up and scaled down
without loss of quality. The image is re-drawn according to the
specifications set by the new size.
Oblique perspective, angular perspective, two-point per-
spective, have lines that vanish in two directions to two different
vanishing points.
Old style type is a type category characterized by mild contrast
between thick and thin parts, and by bracketed serifs.
Orphan is the last line of a paragraph when it is alone at the top
of the next column or page.
Overlapping perspective, cropping perspective, or playing-
card perspective. When certain objects are placed in front of
other objects this will enhance the impression of depth in a pic-
ture. The overlapping perspective was quite common in Euro-
pean mediaeval art.
Paradigm is a set of assumptions or common values that will
influence how people view a community.
Parallel perspective. In a parallel perspective, the distance is
endless. Parallel lines of an object are parallel in the picture too.
Perspective drawing offers possibilities to reproduce depth, but
it is always limited to showing objects from just one certain point.
Passe partout is a border around an image that frame it.
Passive space, or negative space, in a visual is the part that is
not filled with picture elements. The negative space is usually the
256
background. Active space or positive space in a visual is the part
representing different objects. Space has no meaning in itself,
but it may be used to separate or bring together different picture
elements.
Pastiche is an artistic work made in a style that imitates the
style of another artist, period, or work.
Pasteup is an assemblage of the elements of a layout, prepared
for reproduction.
Path layout is the harmonious arrangement of graphic ele-
ments that assume no underlying grid structure.
Perceptual constancy. We can view a picture, a symbol and a
text from various distances and various angles and still get the
same perception of the content. Our minds constantly fill in
missing details and complete images, without our realizing that
it has happened.
Photogram is a “kind of photograph” created without a camera,
for example a copying machine.
Photo illustration is a photography that illustrates an accom-
panying story.
Photograph readability index is used to evaluate photos in
textbooks, based on how a viewer perceives a photograph.
Photomontage is a combination of two or more images.
Pictogram is a symbol used to cross language barriers for inter-
national signage.
Picture readability indexes measure the readability of pic-
tures used in textbooks.
Pixel is a minute rectangular picture element used in “building
blocks,” defined by raster coordinates in digital images. The pixel
can vary with respect to colour.
257
Playing-card perspective, cropping perspective, or overlap-
ping perspective. When certain objects are placed in front of
other objects this will enhance the impression of depth in a pic-
ture. The overlapping perspective was quite common in Euro-
pean mediaeval art.
Point. 1) A point is a location, defined by the crossing of two very
thin lines. 2) A point is the smallest unit of measure in typogra-
phy. It is used for measuring font size, leading, and other items
on a printed page. However, there are different systems in differ-
ent parts of the world. One Pica point is .035 cm. 3) The mathe-
matical point is often represented by a printed dot.
Pointillism is a style of painting with dots. From a distance the
dots merge to produce secondary colours, similar to images on a
television screen.
Positive space or active space in a visual is the part represent-
ing different objects. Negative space or passive space is the part
that is not filled with picture elements. The negative space is usu-
ally the background. Space has no meaning in itself, but it may
be used to separate or bring together different picture elements.
Psychological perspectives are visualisations of psychologi-
cal and subjective sets of values and illusionistic effects. This
group includes imaginary perspective, simultaneous perspec-
tive, and value perspective.
Presbyopia. At about age 40 the tissues of the eyes get stiffer.
It makes it harder for us to shift the distance of our focus.
Raster graphics are computer graphics comprised of bitmaps
that create a grid of individual picture elements (pixels).
Readability of pictures is the ability to understand visual
messages. The style of illustration is decided by the choice of
drawings, photographs, schematic pictures, as well as con-
sistency, expressions, picture elements and symbols. Instruc-
tional illustrations have good readability when the subject
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matter and the pictorial conventions are familiar to the audience
and depicted in a realistic manner.
Renaissance perspective is the same as one-point perspec-
tive or central perspective.
Reversed line perspective, the foreground seems to be
smaller than the background. The straight lines converge in the
direction of the viewer. This perspective is frequent in Japanese
and Chinese art, which seeks to draw the viewer into the picture
to take an active part in the events depicted.
Saturation, sometimes called chroma and intensity, is most
closely related to the number of wavelengths contributing to a
colour sensation. It is the apparent purity, or lack of greyness of
a colour. Saturated colours are often considered to be aggressive,
bold, daring, vibrant and they may grab our attention. Unsatu-
rated colours may be perceived as boring, dull, peaceful, restful,
soft, weak and they may sometimes be depressing. (Sometimes
chroma is said to be the combination of hue and saturation.)
Shade is a base colour with black pigment added.
Shadow perspective. Projected shadows, or drop shadows,
are sharply accentuated as a means of displaying the location of
different objects and their spatial relations to each other. Cast
shadows may create confusion and they may actually impair leg-
ibility and communication. Even some of the old rock paintings
in caves reveal attempts at producing an impression of depth, by
the suggestion of simple cast shadows.
Shape constancy is our tendency to judge shapes as the same
despite changes in distance, viewing angle, and illumination.
This is one of the reasons that circles, ovals, rectangles, squares
and triangles often are used in symbols and icons.
Shapes. The basic elements form shapes that form visual syn-
tagms, or sub-meanings. These components interact to form
complete meanings.
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Simultaneous perspective, was used in Europe during medi-
eval time. It is a spatial dimension in paintings. Several manifes-
tations of the same character or person may be seen in one pic-
ture. The allegories, icons, and symbols that are used determine
to a large degree the interpretation of medieval images.
Size constancy is our tendency to judge sizes as the same de-
spite changes in distance, viewing angle, and illumination. See
Perceptual constancy.
Structure of visual language is formed by image variables
that influence our interpretation of images.
Subtractive colour combination, the dyes, inks, and pig-
ments printed on paper function like filters for the white light
and present colour to the eye by reflection. The wavelengths of
light are absorbed (subtracted) in different ways.
Symbols. Various symbols can be used to aid communication.
An example is a mark for continuation (>). A good symbol is de-
signed so it can be used in many different situations and in many
contexts. A good symbol is simple, clear, has optimal size, good
contrast in form, dimension and colour. There are cultural as well
as individual differences in interpreting the meanings of sym-
bols. Few people share the same understanding of any given sym-
bol. People can usually not guess the meaning of symbols. Sym-
bols should be used in a consistent way. A symbol must always
have the same meaning within a specified context.
Syntagms. The basic elements form shapes that form visual
syntagms, or sub-meanings. These components interact to form
complete meanings. A key syntagm is the “meaning nucleus” of
the visual.
Technical illustrations are diagrams and drawings of man-
made materials, constructions and objects, sometimes including
the situations, in which they are used and the processes and sys-
tems in which they are incorporated. The main purpose is to de-
scribe or explain these objects and constructions to a more or less
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non-technical audience. Images need to be clear and provide an
overall impression of what an object is or what it does.
Texture is the visual equivalent of the sense of touch and the
feel of an object’s surface.
Three-point perspective is usually used in pictures of build-
ings seen from above or seen from below.
TIFF, Tagged Image File Format, is a widely used file format
used for saving scanned, bitmapped images.
Tonal perspective Light tones appear to advance and dark
tones appear to recede. A light object against a dark background
will normally stand forward, with a strong sense of depth. In
practice, it is difficult to distinguish between aerial perspective,
colour perspective and tonal perspective.
Tint is a base colour with white pigment added.
Tonal perspective Light tones appear to advance and dark
tones appear to recede.
Tone, see Value.
Trompe L’Oeil is French for “fool the eye.” A two-dimensional
representation that is so naturalistic that it looks actual, or real-
istic three-dimensional.
Two-point perspective, angular perspective, oblique per-
spective, have lines that vanish in two directions to two different
vanishing points.
Types of visuals. Generally speaking it is not possible to rank
the different types of visuals.
Value perspective, or social perspective. In art of more an-
cient date, and even in primitive art, there are many examples of
perspective based on contents, meaning, and value. The signifi-
cance, rank, status, or value of depicted objects is evident from
the object’s size in the picture.
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Value, tone, is the apparent darkness or lightness of a colour in
anything that is visible. It ranges from black to white.
Vector image, or object-oriented image, is based on mathe-
matical functions and is composed of lines and closed polygons.
Vector. A vector only has mathematical properties. It can be as-
signed basic graphic properties.
Vertical lines are perceived as being longer than equally long
horizontal lines. They are symbols of power, and often stop the
eye movements.
Vertical perspective is a special kind of geometrical perspec-
tive. Here objects in a picture may be placed on a vertical line, as
steps on a ladder.
Visual fusion. When we look at a picture our minds combine
the minute parts by blending and organizing the patterns into
correct images.
Visual literacy is the learned ability to interpret visual mes-
sages accurately and to create such messages. Interpretation and
creation parallel reading and writing in print literacy.
Visual memory is superior to memory for words. This is called
the “pictorial superiority effect.”
Visual messages are superior to verbal messages when content
is emotional, holistic, immediate, spatial and visual. They stimu-
late both emotional and intellectual responses and make us feel
as well as think.
Visual signs do not retain their meaning in the same way as
verbal signs when rotated and turned in different directions
Visual variables are colour, density (or greyness), directions,
form (of symbols), granularity (or texture), position and place,
and size (of symbols).
Visualisation, or visualization, is any technique for creating
animations, diagrams, images, and sketches to communicate
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messages. It is used in education, engineering, medicine, science,
technology, etcetera.
Visualising, or visualizing, a message means that you attempt
to materialize it in an effective synthesis of words and pictures.
Volume. A volume has a three-dimensional form with various
depth planes, or grounds, a foreground, a middle ground, and a
background.
Worm’s-eye perspective, worm’s-eye view, or frog perspec-
tive, is a level perspective. Here an object is viewed from below
(at an oblique angle). This perspective is often used in propa-
ganda. The viewer has to look up to something. In art, film, pho-
tography and video a person seen from this perspective look big,
important, mighty, powerful, strong and tall. However, a too low
view of a person fails to read clearly. This perspective is often
used when there are three vanishing points, one on top, one on
the left and one on the right. This is the opposite of a bird’s-eye
perspective.
x-axis is the horizontal scale to frame a chart or a graph. The
vertical scale is the y-axis.
y-axis is the vertical scale to frame a chart or a graph. The hori-
zontal scale is the x-axis.
Zero-point perspective occurs when the viewer is observing a
non-rectilinear scene like a natural scene. In painting and pho-
tography, the depth of a picture can be visualised in several ways
and not only through a linear perspective.
