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Introduction
Michal Vik currently works at the Department of Material Science, Technical University of Liberec. Michal does research in Colorimetry, Spectroscopy, Photochemistry and Materials Chemistry.
Their current project is 'The validity of CIE Whiteness and Tint equations'.
Current institution
Additional affiliations
January 2009 - December 2012
Publications
Publications (133)
This paper aims to give a brief review of problems occurring in the developing of colour -difference formula. Most of the problems mentioned are well known, but are often forgotten. Work in area colour differences has concentrated on collecting reliable data and developing equations that describe the perceived colour -difference results. Newer equa...
Fresnel’s postulates and equations of energy transfer, including approximate Kubelka – Munk theory, also allow the determination of other optical parameters for measured materials as for example absorbance coefficient k and scattering coefficient s.
In the case of colorants it is possible to determine molar coefficient e0 by absorption spectrophoto...
The article explains the basic concepts of colorimetry and deals with issues of assessment reflectance quality of special plaster coatings in accordance with current methods of measuring spectral reflectance of the International Commission on Illumination (CIE). The results demonstrate that in the case of coatings with high gloss values leads to a...
The Whiteness of textiles, plastics, paper and paints is important aspects, which are considered in daily life. Customers usually prefer white products, especially in summer because of comfort reasons. In addition, white, being an achromatic color has a physiological effect on human sensation. Generally, High whiteness is not possible to get throug...
Colorimetry, the technique based on it, has become the norm in all fields of technology that deals with color in any way. The uses of colorimetry can be summed up under the following headings: color identification codes, systematic description of color phenomena, color quality control (color differences evaluation), color rendering and colorimetric...
The standard flickermeter (voltage flickermeter) algorithm commonly used for the evaluation of flicker severity in current electromagnetic compatibility standards originates from the 1980 s. It was developed to mimic irritation of an average human observer by flickering incandescent lamp as a reference light source and optimized to voltage fluctuat...
The IEC flicker observer model, or light flicker-meter, is an algorithm whose purpose is to assess the severity of flicker produced by artificial lighting. Historically, it was developed by extraction from the voltage flickermeter, and it is thus based on experiments with incandescent lamps. This paper is one in a series of papers focused on verify...
When studying photochromic materials, it is crucial to consider qualities like photostability and durability. Fatigue resistance in a photochromic system is the loss of reversible processes such as photodegradation, photobleaching, and photooxidation. Photochromic compounds undergo reversible colour changes when exposed to external stimuli like UV...
PHOTO-FATIGUE BEHAVIOUR OF PHOTOCHROMIC PRINTS USING CONTINUOUS
UV IRRADIANCE MODES
In this paper, we proposed the preparation of a photochromic nonwoven fabric based on photochromic nanofibers with high color response, which has excellent photochromic properties, good durability, and can quickly return to its original state. Photochromic nanofibers were colored by spiropyran (SP) class of photochromic dyes. The SP was dissolved i...
The photochromic properties of the dye 5-chloro-1,3,3-trimethylspiro[indoline-2,3'-[3H] naphtho[2,1-b] [1,4]- oxazine] were investigated by exposing it to continuous monochromatic irradiation using 360 nm ultraviolet irradiation using photochromic prints at 293.15 2 K; it undergoes a photocoloration and photodecoloration state, thus following the...
This research aimed to create a UV sensor using photochromic pigment in nonwoven form and analyse its fatigue resistance under continuous ultraviolet (UV) light. The photochromic polymeric matrices consist of a photochromic pigment, a polymer, and a photo stabilizer, which enhance the stability of the photochromic systems under light exposure. As a...
The dataset contains 9 colour centres for which colour difference judgements were made using the grey scale method according to ISO 105-A02.
Approx. 30 000 individual judgements,
avg. 15 color normal observers/per color center. 0°:45° sampling geometry. Lighting - CIE D65 simulator, illuminance 1050 lx, N7 background. Sample sizes corresponded to...
A novel treatment technique to confer functions of capturing and detecting hapten metal ions upon cotton fabric by using laccaic acid (LA) was studied for preventing metal allergy symptoms. Cotton fabrics were treated by the LA with using thionyl chloride and pyridine to give the functions. It was found that the LA-treated cotton fabrics adsorbed n...
The pulp and paper, textile, and other industries measure near white materials with well-defined d:8° or d:0° geometry. Many of measured near white materials contain fluorescent whitening agents (FWA). The current CIE Whiteness Index can only be used for samples that do not differ much in color and fluorescence and that are measured on the same ins...
Chromic materials, frequently called as color-changeable materials, became more important in many applications. For example, photochromic colorants are used as in adaptive sunglasses, rewritable CD and its alternatives, indicators, etc. Photochromic dye reversible changes their color with the incoming light intensity or spectral distribution of the...
There is now an increasing emphasis on reducing the overall level of lighting in towns and villages. The priority is to reduce energy consumption thanks to energy costs and decrease a light pollution in towns, villages and general space. This has an understandable impact not only on road safety but a whole range of other situations. The main object...
The colour perception and discrimination are influenced by various aspects. We know from previous studies that one of the biggest influences on colour discrimination is adaptation luminance, or rather its level. The adaptation of the eye itself is also connected with this. As adaptation luminance gradually decreases, we lose the ability to distingu...
Background: Symmetric sigmoidal models with four parameters based on an idealized S/Z-shaped curve are commonly used to analyze the optical parameters of thermochromic materials. However, our experimental findings show that this approach leads to systematic errors involving the incorrect estimation of the transition temperature or the possibility o...
The standard flickermeter algorithm commonly used for the evaluation of flicker severity in current electromagnetic compatibility standards originates from the 1980s. It was developed with an incandescent lamp as a reference light source and optimized to voltage fluctuations caused by arc furnaces. However, the algorithm is questionable as the situ...
The IEC voltage flickermeter and light flickermeter are algorithms used to estimate the severity of flicker produced by artificial lighting systems. The algorithm was developed around incandescent lamps. In an effort to revise and update the algorithm to be compatible also with LED lamps, the flicker sensitivity curve needs to be verified with whit...
The international trade of cotton is based on color and trash, which can be assessed by different methods. Although there are so many instruments in the market to measure the color of cotton, but still now, the visual grading of cotton color is considered to be the most impressive method. Cotton-growing countries have professionally trained persons...
The human visual system is able to adapt to a wide range of the adaptive luminance levels. However, the chroma was found to be the most affected attribute in the assessments. Several color appearance models have been proposed to describe adaptation mechanisms and predict the color appearance at different luminance levels. A set of 72 color pairs of...
Whiteness is an attribute of color perception with high brightness and low colorfulness. In this study, the correlation between instrumental measurement and visual assessment of whiteness of 40 optically brightened white samples was investigated under a LED light source of correlated color temperature (CCT) 5000K combined with Wood's UV-A lamp. Due...
The main objective of this work is to study the fatigue behavior of photochromic textiles under different UV irradiance times and develop a rapid testing method. When considering their possible applications, the fatigue resistance of photochromic materials has been considered. The photochromic woven fabric was prepared using the screen-printing met...
FABRICATION OF UV-RESPONSIVE CHROMIC SYSTEM USING NANOSPIDER DEVICE AND ITS PHOTO-FATIGUE BEHAVIOR UNDER CONTINUOUS MODE OF UV IRRADIANCE
LEDs or light emitting diodes of the lighting class dominate both the indoor and outdoor lighting industries today due to their accuracy and consumer-friendly color temperature. In the context of color science, it is necessary to analyze both the spectral power distribution of lighting and the human characteristics of color perception under these l...
A standardized source of light is essential for visual color assessments, which is why lighting booths were developed. For the best results in visual assessment, it is important to consider the right choice of light source, the right viewing conditions, and the variability of the viewer. To date, many light booth technologies have been introduced t...
The main objective of this work is to study the fatigue behavior of photochromic textiles under different UV irradiance times and develop a rapid testing method. When considering their possible applications, the fatigue resistance of photochromic materials has been considered into account. The photochromic woven fabric was prepared using the screen...
The study investigates retroreflective fabrics’ efficiency from the point of view of the interaction of their visibility, thermo-physiological comfort properties, and durability (represented by physical-mechanical performance). The effect of the combination of two production technologies (reflective transfer films and screen printing method) and tw...
This paper aims to assess specifically the effects of measurement noise on the evaluation of the flicker metrics defined in IEEE Standard 1789-2015. To this end we compare two analytical approaches and Monte Carlo simulations w.r.t. their ability to cope with natural bias of Flicker Percent and to estimate its measurement uncertainty. Two similar d...
Ernst Waldfried Josef Wenzel Mach was born on 18 February 1838 in Chrlice, near Brno, currently in the Czech Republic. While Mach was a talented child, he had difficulties with classical languages, and his initial schooling was not trouble free. He began his schooling at the age of nine at a gymnasium, but he did not complete the curriculum.
Jan Evangelista Purkyně was born sometime between December 17 and December 19, 1787, in the castle in Libochovice near Litomeřice, Bohemia (then part of the Austrian monarchy), now in the Czech Republic. Purkyně died on July 28, 1869.
Paul Kubelka was a Czechoslovakian chemical engineer whose many accomplishments include a theory of light absorption and scattering by a layer of paint. Kubelka was born in 1900 to Austrian parents in Czechoslovakia.
This work was focused on the development of superhydrophobic and UV protective cotton fabric by simple approach. Cotton fabric was coated with TiO2 particles by one step hydrothermal reaction. TiO2 coated fabric was subsequent treated with Trimethoxy(octadecyl)silane (OTMS). The effect of hydrothermal reaction time on synthesis of nanoparticles was...
This paper aims to assess the effect of measurement noise on the evaluation of the flicker metrics defined in IEEE Standard 1789-2015. To this end we compare two analytical approaches and Monte Carlo simulations w.r.t. their ability to cope with natural bias of FP and to estimate measurement uncertainty. Two similar datasets from laboratory experim...
The system under calibration has been previously characterized in photopic conditions. Due to increased interests in mesopic conditions, it was adapted to be usable in such an environment. Preliminary tests raised concerns about the stability of the generated stimulus. This paper retraces the steps which were consequently applied to fully capture,...
Photochromic molecules are well-established colourants in the manufacturing of niche products, providing reversible colour change effects when irradiated with ultraviolet (UV) light. The high material cost of such speciality dyes along with the general high carbon footprint and extensive water consumption of textile products necessitates resource-e...
In this research, metallocene catalyst isotactic polypropylene (miPP) filaments were produced with different concentrations of photochromic pigments to develop ultraviolet (UV) sensing materials. The produced miPP filaments showed good photochromic response under UV irradiation. In this work, six drawing ratios were applied to get the final product...
This paper aims to assess the effect of measurement noise on the evaluation of flicker metrics. We argue that the standard flicker metric-the amplitude of fluctuation of the luminous flux (Percentual Flicker)-is subject to bias when evaluated from noised measurements without proper noise treatment. For the pu rpose of evaluating the confidence inte...
In this study, photochromic fabrics were prepared by incorporating the spirooxazine derivative of 5-chloro-1,3-dyhydro-1,3,3-trimethylspiro[2H-indole-2,3′-[3H]-naphth [2,1-b] [1,4] oxazine on the polyethylene terephthalate (PET) fabric through a sol-gel coating process. The treated fabrics showed good photochromic response under UV irradiation. In...
In this work, surface metallization of cotton fabrics was performed by electroless plating using a shorter route than is conventional. The fabric surface was activated by deposition of silver and copper nanoparticles, and then a thin layer of copper was coated using electroless plating. The performance of coated fabrics was compared in terms of ele...
The development and design of novel functional and smart textile materials such as textile sensors and multicolored systems based on photochromic dyes necessitate controls of color intensities, switching speeds, and material durability. Precise control and synchronization of dye kinetics are important for multi-colored photochromic applications esp...
At present, a quantitative measurement of degree of whiteness is focused on simulation of outdoor lighting D65, based on that direct comparison of whiteness values obtained is confusing in case of light source, which is far in point of view of spectral power distribution to filtered xenon flash lamp that is installed in measuring device. In this pr...
This field of study was designed to investigate effects of retroreflector size, shape and production technology on conspicuity of nighttime pedestrians. The subject's task was to compare two different almost inverse design of retroreflector with focus on effectiveness two reflective transfer films and screen-printed version of retroreflector made f...
Spiro [2H-indole-2,3’–[3H]naphth[2,1-b][1,4]oxazine],1,3-dihydro-1,3,3-trimethyl-6’–(1-piperidinyl) was incorporated onto polypropylene and photochromic polypropylene multifilaments produced through the mass coloration technique. Subsequently the polypropylene (PP) filaments were doped with a different concentration of photochromic pigment, and aft...
Photochromic textiles are of considerable interest for smart and functional textile applications due to their remarkable dynamic colour changing effect when irradiated with light of a certain wavelength. The use of resource efficient processes, such as digital inkjet printing and supercritical carbon dioxide (scCO2) dyeing techniques enables an eco...
Health concerns as a result of harmful UV-rays drive the development of UV-sensors of different kinds. In this research, a UV-responsive smart textile is produced by inkjet printing and UV-LED curing of a specifically designed photochromic ink on PET fabric. This paper focuses on tuning and characterizing the colour performance of a photochromic dy...
Niche products like smart textiles and other technical high-end products require resource-efficient processes and small batches contrary to conventional textile processes that require larger batches and are water-, chemical- and energy-intensive. This study focuses on digital inkjet printing and UV light curing as a flexible and resource-efficient...
For the development of niche products like smart textiles and other functional high-end products, resource-saving production processes are needed. Niche products only require small batches, which makes their production with traditional textile production techniques time-consuming and costly. To achieve a profitable production, as well as to further...
Colour is the visual perceptual property in the cotton grade classification of Universal Cotton Standards. We undertook an experimental study on the variation in cotton colour using the Non-contact method. Rd (degree of reflectance) and +b (yellowness) are globally recognized colour parameters of cotton, which are measured by HVI (High Volume Instr...
Photochromism is a light-induced reversible change in colour defined as: ‘A reversible transformation in a chemical species between two forms having different absorption spectra brought about by photo-irradiation.’ This issue of Textile Progress provides a review of photochromism, the different methods for producing photochromic textiles, their pro...
9 observers visually assessed the whiteness of 10-selected white textile samples by using pair comparison method. Visual ranking of these samples was computed from 2025 individual judgments. Tristimulus values based on measured total radiance factors of the samples are calculated for the CIE1964 supplementary standard colorimetric observer. Visual...
The applications of color changes in an object can be observed frequently in our daily life. These changes may take place either from colorless to colored or from one color to another. Photochromic textiles have been used in the sensible materials (sensor) in the smart textiles and esthetic materials in the fashion industry due to the color changin...
9 observers visually assessed the whiteness of 10-selected white textile samples by using pair comparison method. Visual ranking of these samples was computed from 2025 individual judgments. Tristimulus values based on measured total radiance factors of the samples are calculated for the CIE1964 supplementary standard colorimetric observer. Visual...
The color measurement of the cotton fiber is very important property of the cotton fiber and it plays important role in grading of cotton. Globally used color parameters of cotton fiber are Rd and +b. These parameters are measured by HVI (High Volume Instrument). Cotton color standards are ceramic tiles and cotton samples which are provided by USDA...
For individual components as well as for the final products is need to determine their resistance and other mechanical properties, which can be changing due to the various conditions and simultaneously we try to get still closer to the real operating conditions.Currently, given the need to guarantee a perfect quality of the product throughout its e...
Photochromic textiles have been used in the sensible materials (sensor) in the smart textiles and esthetic materials in the fashion industry due to the color changing properties, which gives immense inspiration to prepare photochromic textile materials, in this regards we take more attention to prepare the mass dyed polypropylene filaments with pho...
High chromatic colours are used largely in various industrial sectors (e.g. textiles, emergency) in last years. Aim of research was observation of influence of decreasing luminance level on assessment of respondents and verification of adaptation mechanisms in mesopic and photopic level human vision. The perception and discrimination of colour affe...
The economic value of cotton is very high as compared to the other natural fibres. And trading of cotton fibre is based on its precise grading on the basis of some important properties. Colour is one of those properties, which play a vital rule for the grading of cotton. Rd (degree of reflectance) and +b (yellowness) are the colour parameters of co...
Dynamic colours are sensitive on different stimuli such as UV-VIS radiation, temperature, humidity, etc. Potential application of these systems in industry, fashion and other branches brings problem of its measurement for purpose of control their quality. For example photochromic colours need to be exposed by external light source during measuremen...
The evaluation of whiteness of a product is dependent from the materials and the application it is used in. Natural materials for example tend to yield some yellowish tint e.g. cotton or wool, so the industry modifies the materials to compensate for this effect (yellowish tint of a product is most often seen as a quality flaw, e.g. yellowed due to...
Nowadays it is a trend to use high chromacitycolours. These colours are using in many applications such as: warning clothes, fashion design and decorative cosmetics. Many companies were focusing on these colours due to high market potential. Therefore, it is important to study these colours and small differences between these colours. In many cases...
Textile materials are one of the basic needs of the human life after food and shelter. It can be
applied in various forms from clothing to high tech applications such as protective textiles,
medical textiles, geo textiles and sport textiles. Consequently, it gives immense inspiration to
prepare photochromic textile materials, in this regards we tak...
This paper reviews the impact of different concentration of photochromic pigment as well as different drawing ratio with respect to the optical properties of multifilament. Temperature variation may induce very significant and different effects on the behavior of the photochromic system, so there is a special device such as LCAM FOTOCHROM, which is...
Dyeing and finishing, being an end of the line process for a textile, traditionally bears a large proportion of the cost of faults. In order to minimize customer rejections and returns, dyers and finishers are forced to suffer the high labor costs associated with detailed manual inspection. And manual inspection is not always a guaranteed solution...
Special-effect finishes are used in many applications to create new color impressions, pronouncing the design of a product and at the same time making the product appear alive. Total appearance conducting color and geometrical factors such as gloss, shape, etc. Gloss is an attribute of visual appearance that originates from the geometrical distribu...
Collisions between vehicles and pedestrians are a significant problem, and substantial evidence indicates that the problem is closely linked with low illumination. A less expensive approach to enhancing the conspicuity of pedestrians involves using retroreflective material – material that has been engineered to passively reflect light back in the d...
The identification and measuring of geometrical dimensions of very small objects including textile is the biggest achievement of the image processing techniques. Not only the analysis of the basic structure of yarn like hairiness, thickness and number of twist but also the external structural analysis like twist parameters and linear density co-eff...
This paper reviews the impact of different concentration of photochromic pigment as well as different drawing ratio with respect to the optical properties of multifilament. Temperature variation may induce very significant and different effects on the behavior of the photochromic system, so there is a special device such as LCAM FOTOCHROM, which is...
Economic value of cotton fiber is by far superior to that of any other natural fiber. And when it comes to trade, cotton fiber and its value added products, the grading of cotton fiber is of high importance which depends upon different properties. Color is one of those important properties which play a vital role in the cotton selection. Currently...
The basis of this research is the evaluation of prediction ability of different color-difference formulas in high chroma yellow-green region of CIELAB color space. Various color-difference formulae, such as CIELAB, CMC, BFD, and CIE94, have been developed in order to facilitate the determination of instrumental tolerances and the measurement of col...
Photochromism is defined as a reversible transformation in a chemical species between two forms having different absorption spectra by photo-irradiation. It is simply a light-induced reversible change of color. Recently, we have produced Photochromic pigments incorporated Polypropylene multifilament with different concentrations of photochromic pig...
The economic value of cotton fiber is far more superior to any other natural fiber. And when it comes to trade the cotton fiber and its value added products the grading of cotton fiber is of very important which depends upon different properties. Color is one of those important properties which play a vital role in the cotton selection. Currently,...
This paper deals with the evaluation of color samples on photopic and mesopic luminance levels. With decreasing luminance level there is shifted the spectral sensitivity to shorter wavelengths. The area of this shift is called as mesopic or mesopic vision. Description of change of the spectral sensitivity of the human eye at change of luminance lev...
The human eye is most sensitive to the wavelength region 555 nm, with decreasing light intensity is shifted the sensitivity of the human eye to shorter wavelengths. Subjective evaluation of observers (Farnsworth-Munsell 100 Hue test and a set of color chips) were performed under seven luminous levels on mesopic and photopic luminance level, which h...
Kalmykia is a unique region in the Russian Federation as its identity dramatically different from other regions of the European part of Russia. It is an intercultural westernmost part of Russia, which professes Buddhism; its traditions are tightly connected with its religion creating a nonrecurring environment. "Navigation system of Kalmykia, Russi...
Color plays an important role in life, which affects our perception, shifting meanings of symbols, emphasizes or suppresses communication of pictograms, logos, brands, acts of emotional perception, affects mood. Color is very important for designers; graphics, artists, and it can significantly affect the acceptance of the artwork, merchantability o...
The basis of this research is the evaluation of prediction ability of different color-difference formulas in high chroma yellow-green region of CIELAB color space. Various color-difference formulae, such as CIELAB, CMC, BFD, and CIE94, have been developed in order to facilitate the determination of instrumental tolerances and the measurement of col...
Using digital image analysis permits a more detailed analysis of such basic structural parameters of linear textile products as thickness, hairiness and number of twists. The process of identifying structural yarn parameters is a significant problem, in the light of both hitherto conducted scientific investigations and current industrial practice....
