Digital video colourmaps for checking the legibility of displays by dichromats

We propose replacement colourmaps that allow a designer to check the colours seen by protanopes and deuteranopes. Construction of the colourmaps is based on the LMS specification of the primaries of a standard video monitor and has been carried out for 256 colours, including 216 colours that are common to many graphics applications of MS Windows and Macintosh computing environments. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 243–252, 1999     

A study of colour emotion and colour preference. Part I: Colour emotions for single colours

This article classifies colour emotions for single colours and develops colour‐science‐based colour emotion models. In a psychophysical experiment, 31 observers, including 14 British and 17 Chinese subjects assessed 20 colours on 10 colour‐emotion scales: warm–cool, heavy–light, modern–classical, clean–dirty, active–passive, hard–soft, tense–relaxed, fresh–stale, masculine–feminine, and like–dislike. Experimental results show no significant difference between male and female data, whereas different results were found between British and Chinese observers for the tense–relaxed and like–dislike scales. The factor analysis identified three colour‐emotion factors: colour activity, colour weight, and colour heat. The three factors agreed well with those found by Kobayashi and Sato et al. Four colour‐emotion models were developed, including warm–cool, heavy–light, active–passive, and hard–soft. These models were compared with those developed by Sato et al. and Xin and Cheng. The results show that for each colour emotion the models of the three studies agreed with each other, suggesting that the four colour emotions are culture‐independent across countries. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 232–240, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20010     

Locating basic colours in the munsell space

This experiment extends the work of Boynton and Olson by providing a replication of their OSA studies, but using the Munsell system. It aims to define the location of the eleven basic surface colours within Munsell space using a monolexemic colour naming technique, and to improve sampling from the red and neutral regions. A comparison of the Munsell and OSA results reveals that while the centroids obtained using the two systems correspond reasonably well, the Munsell focal samples have a much higher saturation than their OSA counterparts. This is undoubtedly due to the more restricted range of the OSA system and calls into question the status of the focal samples previously identified. the existence of Berlin and Kay's eleven basic colour categories is confirmed and their locations identified within Munsell colour space.     

An investigation of colour appearance for unrelated colours under photopic and mesopic vision

Data were obtained for the colour appearance of unrelated colours under photopic and mesopic conditions. The effects of changes in luminance level and stimulus size were investigated. The method used was magnitude scaling of brightness, colourfulness, and hue. Two stimulus sizes (10° and 0.5°) and four starting luminance levels (60, 5, 1, and 0.1, cd/m²) were used. The results at 0.1 cd/m² had large variations, so data were obtained for two additional stimulus sizes (1° and 2°) at this luminance level. Ten observers judged 50 unrelated colours. A total of 17,820 estimations were made. The observations were carried out in a completely darkened room, after 20 min adaptation; each test colour was presented on its own. Brightness and colourfulness were found to decrease with decreases of both luminance level and stimulus size. The CAM97u model predicted brightness more accurately than CIECAM02 but gave worse performance in predicting colorfulness. For hue, CAM97u and CIECAM02 both gave satisfactory predictions. Using the brightness correlate from CAM97u, a new colour‐appearance model based on CIECAM02 was developed specifically for unrelated colours under photopic and mesopic conditions, with parameters to allow for the effects of luminance level and stimulus size. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011;     

Adaptation and colour matching of display and surface colours

In an asymmetric colour matching experiment, eleven observers adjusted computer displays to colour‐match surface samples in a viewing booth. We found systematic discrepancies between the observers' judgments and the predictions of the CIE 1964 Standard Colorimetric Observer. The features of the discrepancies are consistent with previous reports on adaptation in colour matching and on failures of colorimetric additivity, but have never been confirmed to be significant in practical colorimetry. We attribute the discrepancies to post‐receptoral adaptation mainly of the blue‐yellow chromatic channel, and report a framework of an adaptation transform based on the MacLeod‐Boynton chromaticity diagram which can compensate for them without abandoning traditional colorimetry and the use of tristimulus values. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 182–193, 2009     

Individual differences in human colour vision as derived from stiles & Burch 10° colour matching functions

Individual differences between the 49 Stiles & Burch observers have been analyzed using the object‐colour space put forth recently (J of Vision 2009;9:1–23). A set of rectangular reflectance spectra has been used as a common frame of reference for representing object colours for all the observers. Being metameric to one of these rectangular reflectance spectra, every reflectance spectrum can be geometrically represented as a point in the three‐dimentional space. The interindividual differences reveal themselves in that, for various observers, the same reflectance spectrum maps to different points in this space. It has been found that on average such differences do not exceed the differences in object‐colour appearance induced by an illumination shift from daylight to the fluorescent daylight simulator F1. Such small individual variations have been accounted for by the fact that the cone spectral tuning curves have a special form that mitigates the individual differences in cone spectral positioning. © 2012 Wiley Periodicals, Inc. Col Res Appl, 2013     

Faithful representation of colours on a CRT monitor

A method is described to display faithfully on a CRT monitor the colours of images taken by a calibrated digital camera. A multicoloured “input” image, displayed on a monitor, was photographed with the camera. After correcting the digital image to take into account the gammas of both camera and monitor, the image was redisplayed as an “output” image on the same monitor. An iterative procedure found the linear matrix transformation that minimized the difference between the input and output image RGB values. We compared the efficacy of this method with two conventional methods for displaying photographed images on CRTs: the method of displaying the raw untransformed image, and the method whereby the image is transformed via the CIE common frame of reference. The results of the comparisons suggest that the iterative method produces the most faithful representation of the colours of the original image. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 388–393, 2007     

A theory of unique hues and colour categories in the human colour vision

A novel approach to assessing colour appearance is described. It is based on a new technique—partial hue‐matching—which allows for measuring colour in terms of component hues objectively, without resorting to verbal definitions. The new method is believed to have a potential to be as exact as colorimetric techniques. In contrast to classical colour matching, which implies visual equivalence of lights, partial hue‐matching is based on judgements of whether two lights that are different in colour have some hue in common. The major difference between classical colour matching and partial hue‐matching is that the latter is intransitive, whereas the former is generally believed to be transitive (though see Logvinenko, Symposium on 75 years of the CIE Standard Colorimetric Observer, Vienna, Austria, 2006). Formally, partial hue‐matching can be described as a reflexive and symmetric binary relation (i.e., tolerance). The theoretical framework of tolerance spaces is used for developing a theory of partial hue‐matching. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011     

Color association research on red‐green dichromats in the color ergonomics of user interface interaction

With the development of our modern information society, digital products have become integrated into daily life. Research on the color ergonomics of user interfaces is a pressing issue. However, color‐vision‐deficient individuals (CVDIs), who account for 4.25% of the population, must use interfaces designed for individuals with normal color vision; the demands of CVDIs have not been sufficiently addressed. In this article, we investigate color associations in the color ergonomics of user interface interaction in a manner that aims both to improve interaction efficiency and to meet the psychological needs of CVDIs. First, we study color physiological cognitions in the color interactions of user interfaces for red‐green dichromats (RGDs) to determine the single‐color, two‐color, and three‐color combinations with high discrimination for a later experiment. Second, we explore the psychological–cognition relationships of colors in user‐interface interactions for RGDs. In an experiment involving 10 pairs of association semantemes and corresponding colors, the experimental results show that RGDs have different color cognitions caused by specific visual color expressions and unconscious environmental influences. Therefore, this article argues that RGD design should consider not only the habitual colors of solidified cognitions but also instinctive color associations. Finally, based on the results of previous experiments, we apply association color to the new interface design of computer security software (360 Total Security) for RGDs. Experimental results indicate that the application of color association in our new design can improve both interaction efficiency and CVDI user experience. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 547–563, 2016     

Uniform colour spaces based on the DIN99 colour‐difference formula

Several colour‐difference formulas such as CMC, CIE94, and CIEDE2000 have been developed by modifying CIELAB. These formulas give much better fits for experimental data based on small colour differences than does CIELAB. None of these has an associated uniform colour space (UCS). The need for a UCS is demonstrated by the widespread use of the a*b* diagram despite the lack of uniformity. This article describes the development of formulas, with the same basic structure as the DIN99 formula, that predict the experimental data sets better than do the CMC and CIE94 colour‐difference formulas and only slightly worse than CIEDE2000 (which was optimized on the experimental data). However, these formulas all have an associated UCS. The spaces are similar in form to L*a*b*. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 282–290, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10066     

A comprehensive model of colour appearance for related and unrelated colours of varying size viewed under mesopic to photopic conditions

CIE has recommended two previous appearance models, CIECAM97s and CIECAM02. However, these models are unable to predict the appearance of a comprehensive range of colours. The purpose of this study is to describe a new, comprehensive colour appearance model, which can be used to predict the appearance of colours under various viewing conditions that include a range of stimulus sizes, levels of illumination that range from scotopic through to photopic, and related and unrelated stimuli. In addition, the model has a uniform colour space that provides a colour‐difference formula in terms of colour appearance parameters. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 293–304, 2017     

Colour memory for various sky,skin, and plant colours: Effect of the image context

In memory‐matching techniques, the remembered colour might differ from the original colour even if the viewing situation is the same. Our aim was to point out whether these so‐called memory shifts are significant in the everyday situations of viewing photos depicting sky, skin, or plant, or viewing standalone uniform colour patches of sky, skin, or plant colours. In many cases, significant memory shifts have been found. Considering only one type of object (sky or skin or plant), memory shifts turned out to be systematic in the sense that they were directed toward specific intervals of hue, chroma, and lightness. This tendency was more explicit for photos than for standalone colour patches. A method to quantify prototypical colours and their tolerance bounds was suggested. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 278–289, 2001     

Color vision assessment‐1: Visual signals that affect the results of the Farnsworth D‐15 test

The Farnsworth D‐15 test (D‐15) is commonly used to screen for moderate to severe congenital color vision deficiency. The aim of this study was to establish reliable D‐15 statistics for normal, deutan and protan subjects, and to investigate the different visual signals one can use to carry out the test, even in dichromats and rod monochromats. Six hundred and seventy‐four subjects were examined using the D‐15, the Colour Assessment and Diagnosis test and the Nagel anomaloscope. A rod monochromat and five dichromats were tested using the standard D‐15 protocol before the caps were separated into two groups and subjects were asked to repeat the task. D‐15 spectral radiance data, measured under D65 illumination, were used to estimate differences in photoreceptor excitations for each of the caps. When no crossings and up to two adjacent transpositions on the D‐15 results diagram are accepted as a pass, 100% of normal trichromats, 54% of deutans and 43% of protans pass the D‐15. A rod monochromat and two protanopes and deuteranopes were able to complete the D‐15 when the caps were separated into two groups, despite severe loss or even complete absence of color vision. When up to two adjacent transpositions are accepted 50% of color deficient subjects, some with severe red/green loss, pass the D‐15. While the D‐15 is normally used to screen for moderate to severe color deficiency, subjects with severe loss can still use combined, residual red/green, yellow/blue and luminance signals to pass.     

A cross‐cultural colour‐naming study. Part III—A colour‐naming model

A colour‐naming model was developed to categorize volumes for each of the 11 basic names in CIELAB colour space. This was tested with three different sets of data for two languages (English and Mandarin), derived from extensive colour categorization experiments. The performance of the model in predicting colour names was satisfactory, with an average prediction error of 8.3%. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 270–277, 2001     

Performance of the Ishihara,D‐15, and City University colour vision test as a function of intraocular straylight

Three colour vision tests, the Ishihara test, the City University Test (CUT), and the D‐15 test were studied as a function of induced intraocular straylight, using a commercially available light‐scattering filter. Thirty young individuals (aged 17‐28 years) with no ocular abnormalities and normal colour vision participated in the study. Intraocular straylight was estimated in all individuals using a psychophysical compensation method with the C‐Quant straylight meter, with and without the light‐scattering filter which caused an increase in intraocular straylight typical of that found for cataract. Under normal viewing conditions all the subjects passed each of the 3 tests with no errors. When viewing the Ishihara test plates through the filter, 10 out of the 30 observers made at least 1 error. Three subjects also made errors on the desaturated CUT test plates, but all subjects still passed the D‐15 test with the filter. The errors in the Ishihara test correlated with the amount of intraocular straylight, as measured with the C‐Quant. This study indicates that interpretation of the Ishihara test in a clinical environment will be made more difficult in individuals with higher levels of straylight.     

A study of colour emotion and colour preference. Part II: Colour emotions for two‐colour combinations

Eleven colour‐emotion scales, warm–cool, heavy–light, modern–classical, clean–dirty, active–passive, hard–soft, harmonious–disharmonious, tense–relaxed, fresh–stale, masculine–feminine, and like–dislike, were investigated on 190 colour pairs with British and Chinese observers. Experimental results show that gender difference existed in masculine–feminine, whereas no significant cultural difference was found between British and Chinese observers. Three colour‐emotion factors were identified by the method of factor analysis and were labeled “colour activity,” “colour weight,” and “colour heat.” These factors were found similar to those extracted from the single colour emotions developed in Part I. This indicates a coherent framework of colour emotion factors for single colours and two‐colour combinations. An additivity relationship was found between single‐colour and colour‐combination emotions. This relationship predicts colour emotions for a colour pair by averaging the colour emotions of individual colours that generate the pair. However, it cannot be applied to colour preference prediction. By combining the additivity relationship with a single‐colour emotion model, such as those developed in Part I, a colour‐appearance‐based model was established for colour‐combination emotions. With this model one can predict colour emotions for a colour pair if colour‐appearance attributes of the component colours in that pair are known. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 292–298, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20024     

Colorimetric analysis and performance assessment of the Hahn New Pseudoisochromatic Colour Vision Test

Hahn's New Pseudoisochromatic Colour Vision Test contains provision for screening red-green and blue-yellow colour vision deficiencies, a qualitative diagnosis as protan and deutan, and a quantitative diagnosis of red-green deficiencies. In this study 58 colour vision deficient and 68 colour vision normal subjects were examined using a battery of colour vision tests. The screening and classification ability of the Hahn test was compared with Ishihara's Test and the Standard Pseudoisochromatic Plates (SPP). The quantitative diagnosis ability was assessed by comparison with the Farnsworth—Munsell D-15 Test, the Farnsworth Lantern, and the Anomaloscope range. The Hahn proved to have a colour vision screening performance comparable with the two other PIC tests. Its classification ability was poor compared with the other PIC tests, one design in the SPP plates was markedly superior. The Hahn's quantitative diagnosis plates did not produce a useful classification; more than 50% of subjects made the full six errors and only 3 of 58 colour vision deficient subjects made less than 3 errors out of the 6 plates. The colorimetric measurements are used to illustrate the design features and are consistent with these performances. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 69–77 1998     

Some aspects of the visual scaling of large colour differences—II

In an earlier article the authors related visually‐ scaled large colour differences to ΔE* values calculated using four colour‐difference formulae. All four metrics yielded linear regressions from plots of visual colour difference against ΔE*, and ΔE gave the best linear fit, but the correlations were rather low. In an effort to clarify matters, the previous investigation is expanded to include data not hitherto examined. The link between visual colour difference and ΔE* colour metrics is further explored in terms of a power law relationship over a wide range of lightness, hue, and chroma variations within CIELAB colour space. It is shown that power‐law fits are superior to linear regressions in all cases, although correlations over large regions of the colour space are not very high. Partitioning of the experimental results to give reduced data sets in smaller regions is shown to improve correlations markedly, using power‐law fits. Conclusions are drawn concerning the uniformity of CIELAB space in the context of both linear and power‐law behavior. © 2000 John Wiley & Sons, Inc. Col Res Appl, 25, 116–122, 2000     

Seasonal and emotional associations of the colours and their effects on directing the Turkish fashion

This article suggests a potential scientific approach in finding colour effects on human emotions and seasonal associations. A visual assessment of the colour samples was carried out with the help of Turkish observers in Denizli, Turkey. From the study, it was found that Turkish four season colours of spring, summer, autumn and winter were bright green, vivid yellow, dull yellow and dark grayish brown respectively. Moreover, the colour data were arranged in terms of gender and age of the observers. In this analysis, it was observed that the colour preferences changed according to the gender and age of the observers. For instance, the top spring colour preference of young ladies were vivid bluish green, light blue and bright purple, on the other hand the top spring colour preference of adult ladies was light yellow green and the top spring colour preference of young and adult men was bright green. In the study, the observers were also asked about elicited emotional associations of the main colours on their mind and the data were collected in a table. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 523–529, 2016