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Natural Dyes-Unifying The Heritage Of The Past For An Eco-
Friendly Future
A. Tsatsarou-Michalaki, N. Hliopoulos, G. Priniotakis, Ch. Mpoussias
Technological Educational Institute of Piraeus, Department of Textiles,
250, P. Ralli & Thivon Str., Egaleo, 122 44 Greece,
tsatsarou@yahoo.com
Abstract
Coloring is one of the most delightful arts, also one of the most important branches of manufacture; it is
actually difficult to imagine that, but before the mid-19th century professional dyers of fine silks and woolens, had
to rely on such homely substances as dried insects, roots and leaves of plants, and chamber lye, for carrying on
their work. Natural dyes are an education in ecology and ethics. To use natural dyes is to explore the point where
craft and material culture intersect science and natural history. No other dyes provide a better opportunity
teaching how to protect and respect the environment. In the present paper there is an effort taking place to explore
the main environmental dyeing sources and comprehend how the mordants affect the shade and the resistance of
the color.
1. Introduction
Life… Color… Color is life….For thousands of years humans have been using natural
colours for various aspects of their lives, varying from tribal or funeral ceremonies, to body
painting, decorative art, clothing or domestic decoration. At first, sources for the dyes and
pigments were mainly from minerals, insects and plants.
Nowadays, however, different factors, in particular the development of alternative crops, are
encouraging the re-introduction of natural dyes. The evolution of both agricultural policy
(Luxembourg agreements, 23 June 2003), legislation regarding the use of dyestuffs in Europe
(European directive 2002/61/CE), popular demand for more natural products and the toxicity
problem in relation to synthetic dyes are the principal factors in encouraging a revival in the
use of natural dyes. Thus, different projects were encouraged and developed in order to
promote the cultivation of dye plants in Europe over the past several years. In Italy, the
PrisCA project studied several classic plants (Reseda luteola, Rubia tinctorum and Isatis
tinctoria) and it was shown that those species presented a good agronomic potential
(evaluation of different plant collections) and good technological performances (fading
resistance) using ground powder as dye. For instance in the UK, the INDINK project focussed
on I. tinctoria to develop a more efficient indigo production process than in the past (e.g.
agricultural machine development) and to formulate a water-based printing ink.
Natural dying can be approached from a different point of view, that of the conservator and
the ethnologist researcher. Colorants from many geographic areas have been researched, by
many researchers. Historic and ethnographic colorants on textiles have been analyzed on
behalf of many museums, such as the Museum of International Folk Art, the Historical
Museum in Vienna, the School of American Research in Santa Fe, the Natural History
Museum of Los Angeles County, the Museum of the American Indian, and the Asian Arts
Museum, as well as private collectors and dealers.
Scientific studies of artefacts and artists' materials have been part of professional conservation
work since modern conservation's founding in the 1920s and 1930s. Knowing the identity of a
colorant in an artefact, enables a conservator to illuminate, store and clean it appropriately.
Ahead of that, colorant identification helps the researcher to answer numerous questions
about provenience, date, method of manufacture, social and economic significance, exchange
systems, and other aspects of an artefact’s place in society. Thus, it is important that
determining the colorant used on an artefact should not be guesswork. Attempts at colorant
identification by purely visual means are accurate only by chance. An exact identification of
the dye, results in better conservation for the artefact.
For an exact identification of a natural dye, the following factors are needed: a rigorously
vouchered reference collection, a functional technique, a competent practitioner, a sample,
and a sufficient desire to know. While there are a variety of useful analytical methods for
studying dyes, solution spectrophotometry is one of the most preferred, because of two main
reasons: it permits double-blind analyses and it leaves graphic evidence of the results for
interpretation.
2. History review
From the very early times (about 20,000 BC) clothing made of spun yarn had been used, in
large part to allocate the identity and status of the wearer. In order to survive repeated uses
and washings, these colours must be fast, that is, they should not fade when washed or by
being exposed to the light.
Vegetable fibres, like flax, tend to be white or tan, but few colourfast dyes were available in
antiquity. Consequently, Egyptian linen (flax) textiles of the dynastic period (3000 BC - 1250
BC) were white in colour. By about 4000 BC, sheep began to be domesticated increasingly
for wool rather than meat. One advantage of wool over flax is that it comes in a variety of
natural colours, from white to tan, to brown, grey, and black. Thus cloth woven from coloured
wool can exploit a variety of weaving patterns which would be almost invisible in uncoloured
linen. In antiquity, coloured wools would have sold at a premium and even today they are
expensive relative to white wool.
The use of coloured wool then was a great advance in the ability of textiles to connote wealth
and status. But the larger advance came as a consequence of the ease with which wool can be
dyed. The first stains were probably accidental. Nuts and berries collected for food came in
contact with clothing and stained them. Most of these colors washed out, particularly with
soap and water. But some of the stains proved colorfast and over time plant materials were
likely collected for dyeing rather than eating. In 331 BC, Alexander finds 190 year old purple
robes when he conquers Susa, the Persian capital. They were in the royal treasury and said to
be worth $6 million (equivalent), which makes it priceless. During the 2nd and 3rd Century
AD Roman graves found with madder and indigo dyed textiles, replacing the old Imperial
Purple (purpura), which was too expensive for the average people. Because of that, a 3rd
Century papyrus found in a grave contains the oldest dye recipe known, for imitation purple -
called Stockholm Papyrus. It is a Greek work. In 273 AD Emperor Aurelius refused to let his
wife buy a purpura-dyed silk garment. It cost its weight in gold. Late 4th Century Emperor
Theodosium of Byzantium issued a decree forbidding the use of certain shades of purple
except by the Imperial family on pain of death. During 400 AD Murex (the mollusk from
which purpura comes) becoming scarce due to huge demand and over harvesting for Romans.
One pound of cloth dyed with Murex worth $20,000 in terms of our money today (source:
Emperor Augustus). In the 700's, a Chinese manuscript mentions dyeing with wax resist
technique (batik). In 1464 Pope Paul II introduced the so-called "Cardinals' Purple" which
was really scarlet from the Kermes insect. This became the first luxury dye of the Middle
Ages just as Imperial Purple (Murex) had been for the ancient world. In the year 1856
William Henry Perkin discovered the first synthetic dye stuff "Mauve" (aniline, a basic
dye) while searching for a cure for malaria and a new industry was begun. It was a brilliant
fuchsia type color, but faded easily so our idea of the color mauve is not what the appearance
of the original color was.
Figure 1
Figure 3- The chemical
structure of indigo dye
However, with advances in chemical techniques, the manufacture of synthetic dyes became
possible, leading to greater production efficiency in terms of quality, quantity and the
potential to produce low-cost raw materials. As a result, natural dyes were progressively
replaced by synthetic dyes.
3. Dyeing Materials
Natural dyes were the main source of textile colour until the mid- to late-19th century.
Flavonoids (flavones and flavonols) are the main chromophores in the most commonly used
yellow dyes.
They occur in plants as sugar derivatives, are hydrolyzed in the dye-bath to the parent
aglycone, and they bind to the fibre through a metal complex with the mordant via the
carbonyl group and the adjacent phenolic group. Since many plants are rich in flavonoids, no
individual source of yellow dye became predominant–as, for example, did the red dyes
madder and cochineal–and many different and local sources have been in use at the same time
in Western Europe. The most common yellow dyes were extracted from weld (Reseda luteola
L.), young fustic (Cotinus coggyria Scop.), dyer's broom (Genista tinctoria L.), sawwort
(Serratula tinctoria L. Gaud.) and the berries of some species of Rhamnus. Later on, old fustic
(Chlorophora tinctoria L. Gaud.) was introduced from the West Indies and, in the 18th century,
quercitron bark (Quercus velutina L.) began to be imported from North America.
¾ Pokeberry Dye
Pokeberry makes an intense red dye. It is the original "garnet" of the Hampden-Sydney
school colors. Without a mordant, however, pokeberry is not colorfast.
Sodium carbonate (soda ash, washing soda) can be used as a mordant.
About half a dozen of berries’ "heads" should be collected and placed in
a pot or beaker with 250 mL of water. The berries should be crushed, so
that the juice colors the water. Heat the juice on a hotplate until it is hot
to the touch, but do not boil. Boiling the juice will destroy the color.
Properly mordanted, pokeberry dye is colorfast but not lightfast.
¾ Alkanet Root: (Alkanna Tinctoria)
This will give colors from bluish grey to soft burgundy. This plant will grow like a
weed if one wants to grow it.
¾ Annato Seed: (Bixa Orellana)
Will give an orange shade, it is a good dye for cotton.
¾ Brazilwood Dust: (Caesalpania Echinata)
This dye will give you reds. Before using the dust, expose
it to the air and sprinkle with water and alcohol.
¾ Cochineal: (Dactylopius Coccus)
The little cochineal bug will give the most color when
ground into a fine powder. Obtainable colors are dark
burgundy to bright red to soft lilac and pink.
¾ Cutch Extract: (Acacia Catechu)
Cutch is a very easy dye. It will remain fast even on
cottons and silks. It is good for combinations and produces
brown tones if used by itself.
¾ Indigo Natural: (Indigo Tinctotia) Figure 3
Natural Indigo comes in blocks which, without further
preparation, dyeing would not be possible as it does not
dissolve in water. A recipe and reducing agent are needed.
The color range that is produced is blue.
Figure 2
¾ Indigo Solution Natural: (Saxony blue)
Produces a bright blue and is very easy to use, similar to a chemical dye. All of the
dye will be absorbed in the fiber. It is not very good to dye cotton nor other vegetable
fibers.
¾ Loqwood Concentrate: (Hematoxylon Campechianum)
Expected colors anywhere from magenta's and brown to purples and pink. A mordant
is absolutely needed. The concentrated powder will give more bluish colors. It dyes
cotton well.
¾ Madder root: (Rubia Tinctorum)
Is available in two forms: root or dust. Colors
range anywhere from red to red-brown and
oranges. It dyes cotton well.
¾ Osage Orange Dust: (Maclura Pomifer)
Also available in two colors; bright yellow and
gold. Two different colors can be obtained.
¾ Red Sandalwood: (Pterocarpus)
This dye is beautiful for blending. It produces
lovely browns, good shade combinations for doll hair.
In the following table there are given the botanical names and the parts that they are used to
extract the dye.1 number Plant Part of plant used
1 Achillea millefolium L. Whole plant
2 Alcea rosea L. var. nigra Flowers
3 Alchemilla vulgaris L. Leaves
4 Alnus glutinosa (L.) Gaertn. Leaves
5 Anthemis tinctoria L. Flowers
6 Artemisia absinthum L. Flowers head
7 Artemisia vulgaris L. Leaves and stems
8 Betula alba Roth. Leaves
9 Coreopsis tinctoria Nutt. Whole plant
10 Cosmos sulphurous Cav. Flowers
11 Cotinus coggygria Scop. Wood
12 Cotinus coggygria Scop. Leaves
13 Eupatorium cannabinum L. Whole plant
14 Fagopyrum esculentum Moench Whole plant
15 Filipendula ulmaria (L.) Maxim Head flowers
16 Fraxinus exelsior L. Leaves
17 Galium aparine L. Roots
18 Galium mollugo L. Roots
19 Geranium robertianum L. Whole plant
20 Inula helenium L. Leaves
21 Inula viscosa L. Whole plant
22 Alcea rosea L. var. nigra Flowers
23 Alchemilla vulgaris L. Leaves
24 Alnus glutinosa (L.) Gaertn. Leaves
25 Anthemis tinctoria L. Flowers
26 Lycopus europaeus L. Leaves and stems
27 Malus domestica L. Leaves
28 Malva sylvestris Borkh. Whole plant
29 Potentilla erecta (L.) Ra¨usch. Roots
30 Quercus robur L. Leaves
31 Reseda luteola L. Whole plant
32 Rhus typhina L. Leaves
33 Ribes nigrum L. Leaves
1 In natural dyeing there are specific parts of the plant used each time. Sometimes different parts of the
same plant can give different shades or nothing at all. However the shade can be influenced each time
by environmental aspects which makes very difficult to accomplish the exact same shade while
repeating the same dyeing recipe.
Figure 4-
The chemical structure of madder dye
34 Rubia tinctorum L. Roots
35 Rumex obtusifolius L. Roots
Table 1-plants used in natural dyeing
4. Mordants for Natural Dyeing
Mordants are needed to set the color when using natural dyes. Different mordants will give
different results.
¾ Alum: (Aluminum Potassium Sulfate)
This is the most widely used mordant. Be careful not to use too much with wool,
otherwise you will get a sticky feeling that doesn't come out.
¾ Copper: (Copper Sulfate)
This mordant is used to bring out the greens in dyes. It will also darken the dye
colors, similar to using tin, but is less harsh.
¾ Chrome: (Potassium Dichromate)2
Chrome brightens dye colors and is more commonly used
with wool and mohair than with any other fiber.
¾ Iron: (Ferrous Sulfate)
Dulls and darkens dye colours. Using too much will make
the fiber brittle.
¾ Glaubersalt: (Sodium Sulfate)
Used in natural dyes to level out the bath. Also use in
chemical dye.
¾ Spectralite: (Thiourea Dioxide)
This is a reducing agent for indigo dyeing.
¾ Tara Powder: (Caesalpinia Spinosa)
Tara Powder is a natural tannin product. It is needed for
darker colors on cotton, linen and hemp.
¾ Tartaric Acid: A must for cochineal. This mordant will expand the cochineal colors.
¾ Tin:(StannousChloride)
Tin will give extra bright colors to reds, oranges and yellows on protein fibres. Using
too much will make wool and silk brittle. To avoid this you can add a pinch of tin at
the end of the dying time with fibre that was premordanted with alum. Tin is not
commonly used with cellulose fibres.
¾ Calcium Carbonate:
Is to be used with indigo powder for the saxon blue color. It can also be used to lower
the acidity of a dye bath.
Below there are some examples showing how different mordants can affect the final shade of
the dyed material and how it can influence the color fastness.
As it can be seen in table 2 and in Figure 6 an Eclipta dye extract, when dyeing cotton fabric,
can give six different shades by using six different mordants. In general it can be concluded
that Eclipta dye exhibits fair to good fastness to rubbing and good fastness to light and
2 This mordant is extremely toxic. Chrome should not be inhaled and gloves should be worn
while working with chrome. Left over mordant water should be disposed of at a chemical
waste disposal site and treated as hazardous waste.
Figure 5-some yarn dyed
with different mordants
washing. Hence this dye is well suited for cotton, which is subjected to laundering more often
than their synthetic counterparts.
Table 2
The fastness properties of Eclipta dye extract
1 2 3
4 5 6
Figure 6
- Shades obtained by Eclipta alba on Cotton fabric with different mordants
Where: 1 = CuSO4, 2 = FeSO4, 3 = K2SO4-Al2(SO4)3, 4 = SnCl2, 5 = K2Cr2O7, 6 = SnCl4
In Figure 7 it can be seen woollen fabric dyed with almond tree dye extract. Two different
mordants were used which influence the shade. The samples’ colourfastness in light were
tested. They were rated as a 4 when K2Cr2O7 and 3/4 when bleach is used as mordant.
1 2
Figure 7- Shades obtained by almonds barks and leaves on Wool fabric with different mordants
where: 1= K2Cr2O7 2=leach
In Figure 8 it can be seen woollen fabric dyed with onion skins dye extract. Two different
mordants were used which is obvious that influence the shade. The samples’
colourfastness in light was tested. They were rated as a 5 when K2Cr2O7 and 4/5 when
bleach is used as mordant.
Dyed fastness properties Rubbing Perspiration
Mordant
Pre Wash Light
Dry Wet Alkaline Acidic
Stannic chloride Khaki brown 4/5 4 5 4 3/4 4/5 4/5
Stannous chloride Yellowish brown ¾ 4 3 3/4 4 4
Ferrous sulphate Greenish black 4 4 3 4 3 4 4 4
Alum Brownish green 4 4 3/4 3 4 3 4 3 4
Potassium dichromate Light mehndi green 4 4 3 4 3 4 3 4 3 4
Copper sulphate Dark mehndi green 4 4 4 4 4 4
Formatted: Font: (Default)
AdvTimes, 8 pt, Bold
1 2
Figure 8- Shades obtained by onion skin on Wool fabric with different mordants
where: 1= K2Cr2O7 2=leach
NO
MORDANT
ALUM
(deepens)
Copper
sulphate
Ferrous
sulphate
(saddens)
TIN
(brightens)
ALKANET gray/blue purple brown/purple purple/black deep mauve
BRAZIL
WOOD
pink to
yellow
salmon to
rose
brown/salmon
to rose
rosy brown/
purple pink rose
CUTCH rusty tan rusty brown brown gray brown rusty gold
HENNA brown brown khaki/brown dark brown red brown
LOGWOOD blue to
brown
gray/brown
/purple gray/blue purple/grey dark purple
MADDER pink tan deep orange dark tan brown orange
OSAGE light yellow green/yellow light olive olive bright yellow
INDIGO blues no mordant required, it's a different process
COCHINEAL pink crimson dusty purple gray/purple-
black red
Table 3- Different shades from different mordants
5. Other factors
In the following it is discussed briefly how the final shade result of the two main procedures
of extracting the natural dye are affected by some factors such as ph, dyeing time, salt
concentration and temperature.
Effect of dye bath pH
Figure 9 shows that the pH values of the dye bath, have a considerable effect on the dyeability
of cationised cotton fabrics with lac dye under both ultrasonic extraction dyeing (US) and
conventional extraction heating (CH) conditions. As the pH increases the dyeability,
decreases. The effect of dye bath pH can be attributed to the correlation between dye structure
and cationised cotton fibres. Since the dye used is a water-soluble dye containing carboxyl
groups, it would interact ionically with the protonated terminal amino groups of cationised
cotton fibres at acidic pH via ion exchange reaction. The anion of the dye has a complex
character, and when it is bound on fibre, further kinds of interactions take place together with
ionic forces. This ionic attraction would increase the dyeability of the fibre as clearly
observed in Figure 9 . At pH > 2.5, however, the ionic interaction between the carboxylate
anion of the dye and cationised cotton fibres decreases due to the decreasing number of
protonated terminal amino groups of cationised cotton fibres and thus lowering its dyeability.
It is to be mentioned that the lower dyeability at pH > 2.5 may be attributed to the enhanced
desorption of the dye as its ionic bond is getting decreased.
Figure 9
Effect of salt addition
Dyeing of proteinic fibres with high affinity anionic dyes necessitates the use of salt in the
dye bath for obtaining level dyeings. Cationised cotton (aminated fibres) is considered to
behave similarly with those of proteinic fibres in its dyeability with anionic dyes. Figure 10
shows the effect of salt concentration on the colour strength obtained for the dyed fabrics.
Expectedly, the colour strength was better in the absence than in the presence of salt.
Figure 10
Effect of temperature
The effect of temperature on the dyeability of the cationised cotton fabrics with natural dye
was conducted at different temperatures (30 & 800C) in each method. As shown in Figure 11,
it is clear that the colour strength increases with increase in dyeing temperature. Generally,
the increase in dye-uptake can be explained by fibre swelling and hence, enhanced dye
diffusion.
Figure 11
Effect of dyeing time
The effect of dyeing time was conducted at high concentration of the dye, i.e. 8 g/100 ml
water to reveal the effect of power ultrasonic on the de-aggregation of dye molecules in the
dye bath as indicated by higher dye-uptake. As shown in Figure 12, the colour strength
obtained increased as the time increased. The decline in the dyeability may be attributed to the
desorption of the dye molecules as a consequence of long dyeing time.
Figure 12
6. Analyses and Identification
The analysis of the materials used in textile dyeing may be a valuable tool to understand how
an object originally looked, where it comes from and how old it is. This knowledge also
allows conservators to choose appropriate procedures for restoration. Organic colorants used
in textiles are among the most fugitive materials exploited in works of art. Identifying dyes in
old textiles is particularly arduous above all because of the complexity of the degradation
processes undergone by the organic molecules, which are particularly sensitive to light.
Recognizing the pattern of changes in the dye structure could help in choosing museum
conditions such as light levels and excluding ultra-violet radiation, and thus in reducing
degradation risks in conservation.
Thin layer chromatography has historically been employed for the separation and
identification of the components of natural dyes. The most commonly used method for the
analysis of organic dyes is reverse phase high pressure liquid chromatography (RP-HPLC)
with the aid of a spectrophotometric UV–Vis detector. The analytical procedure has been
improved by the introduction of diode array detectors and mass spectrometric detectors. MS
detectors provide helpful information on the structure of degradation products, which may be
present in historical or archaeological samples due to ageing processes. With regard to
flavonoid dyes, which are more subject to degradation by photo-oxidation than other
colorants, low-molecular weight degradation products have been detected. In the study of
natural dyes, gas chromatographic techniques have not been much exploited, due to the
relatively high-molecular mass and polarity of the target compounds. Derivatisation of the
components of the fibre extract is thus mandatory. In fact, to bypass any sample pre-
treatment, pyrolysis coupled with gas chromatography has been tentatively used.
6. Conclusions
Natural dyes are mostly eco friendly. Although some of the mordants can be proved toxic,
they can be avoided and replaced with something innocent to our health. Both dyeing material
and final product are not toxic. On the contrary, there are many of the synthetic once or the
added substances during the dyeing procedure, which are extremely toxic and hazardous.
The last few years, many colour industries especially in USA have been turned to natural
dyeing. The whole philosophy of those industries is included in the table below:
NATURAL DYE SYNTHETIC DYE
Use of Renewable sources Consumption of Non-Renewable resources like crude
oil and its by-products.
Lack of toxicity during production and
reduction of work hazards Work hazard during production
Fully biodegradable and less environmental Impact. High environment Impact during production.
Fully biodegradable and less environmental Impact. Problem of solid waste and liquid effluent disposal.
There are thousand of plants in nature that can be used as a dye with brilliant results. These
materials give final products with a great variety of shades that some of them synthetic dyes
can’t imitate. Besides, mordants can really influence the shade and the fastness of the dye.
Hence, the dyer multiplies the different shades he can achieve, by different dyeing material.
As far as it concerns the fastness properties of the dyed material, somebody could dare to say
that they are comparable to those dyed with synthetic dyes. In sometimes it is even better,
depending on the mordant used during the dyeing procedure.
Another aspect is the analysis of the already dyed materials. Knowing the natural dyeing
substances used can be extremely helpful when needing to conserve an artifact. It will help
the researcher to spot the chronology of the artifact, its origination, and the necessary
materials and methods in order to efficiently conserve it.
7. References
1. R. Adrosko, M. Smith Furry, “Natural Dyes and home dyeing”, Courier Dover Pub., 1971
2. Z.C. Koren, “Dyes in history and archaeology”, 13, 1994
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4. R. Bachanan, “A Weaver’s Garden”, Courier Dover Pub., 1999
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μαθημάτων του εθνικού αρχείου ελληνικής παραδοσιακής ενδυμασίας, Ναύπλιο, 2000
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Łucejko, “Colour fading in textiles: A model study on the decomposition of natural dyes”
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12. Gcpc Envis, “Natural dyes”, Vo.4, No.2, 2006
13. C. Walker, H.L., “Needles, Historic textiles and paper materials, conservation and
characterisation”, 1986
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silk fabrics without metal mordants”, Journal of Cleaner Production 15 (2007)
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