Hue cycle described by graphs and color names

The color appearance of the hue cycle in equal radiance is described in hue, saturation, and brightness/lightness. The latter does not resemble CIE luminance Y (peaking at 555 nm green), but peaks near 570 nm yellow with minor peaks near 490 nm cyan and 530 c magenta. Saturation per watt peaks near 450, 530, 610 nm (blue, green, red). Newton's choice of seven spectrum colors, and particularly his two bluish colors, is explained as major colors rather than merely different hues.     

Complementary colors theory of color vision: Physiology,color mixture,color constancy and color perception

I describe complementary colors' physiology and functional roles in color vision, in a three‐stage theory (receptor, opponent color, and complementary color stages). 40 specific roles include the complementary structuring of: S and L cones, opponent single cells, cardinal directions, hue cycle structure, hue constancy, trichromatic color mixture, additive/subtractive primaries, two unique hues, color mixture space, uniform hue difference, lightness‐, saturation‐, and wavelength/hue‐discrimination, spectral sensitivity, chromatic adaptation, metamerism, chromatic induction, Helson‐Judd effect, colored shadows, color rendering, warm‐cool colors, brilliance, color harmony, Aristotle's flight of colors, white‐black responsivity, Helmholtz‐Kohlrausch effect, rainbows/halos/glories, dichromatism, spectral‐sharpening, and trimodality of functions (RGB peaks, CMY troughs whose complementarism adapts functions to illuminant). The 40 specific roles fall into 3 general roles: color mixture, color constancy, and color perception. Complementarism evidently structures much of the visual process. Its physiology is evident in complementarism of cones, and opponent single cells in retina, LGN, and cortex. Genetics show our first cones were S and L, which are complementary in daylight D65, giving a standard white to aid chromatic adaptation. M cone later split from L to oppose the nonspectral (red and purple) hues mixed from S+L. Response curves and wavelength peaks of cones L, S, and (S+L), M, closely resemble, and lead to, those of opponent‐color chromatic responses y, b, and r, g, a bimodal system whose summation gives spectral‐sharpened trimodal complementarism (RGB peaks, CMY troughs). Spectral sharpening demands a post‐receptoral, post‐opponent‐colors location, hence a third stage. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011     

Individual differences of unique hue loci and their relation to color preferences

Loci of the four unique hues (red, green, blue, and yellow) on the equiluminant plane on the color display and three preferred colors were obtained from 115 normal trichromats. We sought possible correlations between these measures. Different unique hue loci were not correlated with each other. The three preferred colors were not correlated with each other. We found five combinations of significant correlation between a preferred color and unique hue settings, yet the overall tendency is not very clear. We conclude that individual differences in color appearance measured by unique hues and color preferences measured by asking for favorite colors may not be predicted from each other or even within a category because the differences in the earlier visual mechanisms can be compensated for and these high‐level measures can be influenced by learning and experience. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 285–291, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20023     

Theory of corresponding colors as complementary sets

A corollary of Grassman's linearity law is formally derived, and states: If a number of colors have a corresponding color appearance A in different illuminants, then their complementary colors have a corresponding color appearance B. The informal logic is that: (1) a perceived color has only one complementary color; (2) two or more corresponding colors have the same complementary color (given the illuminant whites are a color match); so (3) the complementary colors to corresponding colors will themselves be a set of corresponding colors. A method of predicting corresponding colors is derived theoretically and shown to agree with data. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 371–381, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.     

网络出版中文字背景色的优化

网络出版的阅读基于屏幕显示,不同于纸质出版,显示屏幕上呈现文字信息可不拘泥于白色背景。实验针对不同字体和字号的黑色文字,设计了亮白和红、黄、绿、蓝、品红、灰等不同色相的背景颜色,并在一定范围内改变其明亮度和彩度。视觉观测结果表明,因屏幕自发光的亮度很大,其最亮的白色并不适于黑色文字的显示,适合的白色背景是明亮度降低后的一定范围内的灰色。类似地,其他所实验的彩色,适于作为背景色的明度和彩度也都有一定的范围。就适于的范围大小比较而言,包括灰色在内,灰色、黄色、绿色和蓝色的明度范围明显大于红色和品红色;绿色、黄色和蓝色的彩度范围也明显大于红色和品红色,其中绿色的彩度范围尤为宽泛。     

Variability in Unique Hue Selection: A Surprising Phenomenon

Data from ten different experiments involving nearly 600 observers of determination of unique hues are compared. Six experiments involve determination using spectral lights; two use desaturated monitor colors, and the remaining two use color chip sets. Except for unique green, color chips result in narrower ranges of results than spectral lights. Unique green has a surprisingly large range of variation in both spectral light and color chip experiments, followed by red. Comparison of spectral light data indicates that one observer's unique blue can be another's unique green and vice versa, and the same for yellow and green. This finding raises significant questions for color appearance and color space/difference models, as well as philosophy of color. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 158–162, 2004;Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10237     

Japanese and Korean ideas about clothing colors for elderly people: Intercountry and intergenerational differences

This study evaluated the clothing colors worn by elderly persons. We took photos, with elderly persons as models, displayed them on a computer screen, and used computer graphics to produce 75 colors of clothing worn by elderly persons. The 75 colors were evaluated by Japanese and Korean elderly women and female students. We compared the ideal colors and colors actually worn by elderly women in Japan and Korea. The ideal clothing color worn most often, and the images held concerning these colors, were found to differ between elderly women and female students in Japan and Korea, between Japanese and Korean elderly women, and between Japanese and Korean female students. In brief, the ideal clothing color for elderly women was the color satisfying brilliance, functionality, and elegance. We found that Japanese consumers prefer clothing of red hue or light grayish‐orange, whereas Korean consumers prefer colors of cold hues or achromatic colors. The differences observed between Japanese and Korean women seem to be associated with various factors, including traditions, culture, public morals, and racial consciousness. Differences in the rate of aging in the society and the timing of this change may also be involved. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 139–150, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10132     

Preference for accent and background colors in interior architecture in terms of similarity/contrast of natural color system attributes

Color combination criteria are said to entail an affective response in interior design. We investigated the color combination criteria that orient the preference of current observers, after Le Corbusier's 1931 Salubra keyboards. We explored the similarity/contrast in Natural Color System (NCS) hue, blackness, and chromaticness in 312 combinations with four colors, two backgrounds and two accent colors, coming from 43 individual colors, on the walls of a simulated interior of a bedroom from the Swiss Pavilion (Le Corbusier, 1930-1931). Participants were 644 students of architecture and interior design in Western Europe and Near East, who evaluated with a Likert scale their preference for virtual images via an online survey. Results indicate that the most preferred color combinations are those with hues closer in the color wheel, being the similarity between hues in the backgrounds more important than in the accent colors, and with NCS B30G to G as the most preferred hues. Observers preferred color compositions with blackness under 10% and similar blackness between the two background colors, together with a certain blackness contrast between these background colors and the two color accents. Similarly, observers liked color compositions with low chromaticness and low chromaticness difference among the four colors of the composition.     

Color preference affected by mode of color appearance

Most color preference research focuses on colors in an object color mode. In our daily life, however, colors are perceived not only as an object color mode but also as other modes, such as unnatural object color and light source color modes. To explore the effect of the color appearance mode on color preference, we examined the relationship between color preference and the mode of color appearance. Thirty‐three color chips were chosen from the Munsell notation varying in hues and chromas. The color chips were presented in different color appearance modes by changing the subject's room illuminance and the color chip room illuminance. The experimental results showed that the brightest and most saturated colors were preferred. It was found that the subject preferred color in a light source color mode and unnatural object color mode to color in an object color mode. Moreover, we found that hue had a small effect on color preference in the light source color mode. We also investigated the relationship between color preference and the perceived color attributes (perceived chromaticness, whiteness, and blackness). In a supplementary experiment, elementary color naming was conducted. The results showed that the perceived chromaticness, perceived whiteness, and perceived blackness play a role for the determination of color preference for different color appearance modes. We, consequently, suggest that color preference is dominated not only by color attributes but also by the mode of color appearance. © 2009 Wiley Periodicals, Inc. Col Res Appl, 2010     

Gray and grayness—its complexities in color appearance of surface colors

Complexities on the roles of reference color gray and grayness are reviewed. They are essential in color appearance, but gray is an implicit color. Although “grayness” is not explicitly used in visual color assessment of surface colors or color order systems, gray can be combined with any colors having six primary‐color components using the term “grayish,” for example, grayish red and grayish yellow. However, the existing region of grayness is limited in a part of color‐appearance space. Illuminance dependency of gray perception is also clarified. Existence of two kinds of psychometric quantities are suggested: one is the attribute of grayness based on its psychological amount in a grayish color under study, and the other is the attribute of brightness of the grayish color under a specified illuminance, psychophysical quantity. The Nayatani‐Theoretical color order system, which uses three opponent‐colors axes, can clarify the above complexities of gray and grayness. Its importance is the same as six primary colors, red–green, yellow–blue, and white–black. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 37–44, 2014     

What color do you feel? Color choices are driven by mood

Popular opinion holds that color has specific affective meaning. Brighter, more chromatic, and warm colors were conceptually linked to positive stimuli and darker, less chromatic, and cool colors to negative stimuli. Whether such systematic color associations exist with actually mood felt remains to be tested. We experimentally induced four moods—joy, relaxation, fear, and sadness—in a between‐subject design (N = 96). Subsequently, we asked participants to select a color, from an unrestricted sample, best representing their current mood. Color choices differed between moods on hue, lightness, and chroma. Yellow hues were systematically associated with joy while yellow‐green hues with relaxation. Lighter colors were matched to joy and relaxation (positive moods) than fear and sadness (negative moods). Most chromatic colors were matched to joy, then relaxation, fear, and sadness. We conclude that color choices represent felt mood to some extent, after accounting for a relatively low specificity for color‐mood associations.     

Preprocessing to CIECAM02 input color with chromatic background

A preprocessing to CIECAM02 input color for color appearance prediction was proposed. In this study, 8640 color appearance matching pairs (NCS color charts with red, green, yellow, and blue backgrounds in a light booth and their reproductions with gray background on a CRT screen) were obtained by psychophysical experiment using the simultaneous‐binocular technique. Because only the lightness of background is included in CIECAM02, a color inducing vector based on opponent‐colors theory was introduced to preprocess CIECAM02 inputs, so that CIECAM02 may predict the corresponding color of an input color with chromatic background as well. By data fitting, a color preprocessing formula describing a relationship between the color inducing vector and the NCS chromaticness was conducted. Furthermore, the formula's performance was tested and the results showed that it was good for implementing the color appearance prediction of input colors with different chromatic backgrounds.© 2006 Wiley Periodicals, Inc. Col Res Appl, 32, 40–46, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20287     

Adequateness of a newly modified opponent‐colors theory

Two features of a newly modified opponent‐colors theory are examined for correctness: (1) The perceived chroma of pure color is different for different hues. This was confirmed by using Ikeda's UCS (Uniform Color Scales) formula and also by the maximum Munsell Chroma Values for different hues. (2) Chromatic colors with the same values of whiteness, blackness, grayness, and perceived chroma have the same perceived lightness and chromatic tone regardless of hue. This was confirmed by a theoretical analysis and observations of the color samples in the Practical Color Co‐ordinate System (PCCS) developed in Japan. Chromatic tone, a complex concept of object colors, is clarified. The structure of the newly modified theory and its corresponding color space were confirmed by observation of object colors. Furthermore, it was found effective for developing a color‐order system and its corresponding standard color charts to the modified theory. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 298–307, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10164     

Color constancy from invariant wavelength ratios. II. The nonspectral and global mechanisms

Given the spectral mechanism of color constancy (Part I of this series), the remaining nonspectral mechanism is formulated here in Part II by the constraint of correlation with known spectral illuminant–invariant functions, i.e., invariant wavelength ratios between constant hues, which plot straight parallel lines in the plane of wavelength and reciprocal illuminant color temperature (MK^?1). The same is assumed to apply to nonspectral constant hues in the same plane and dominant wavelength scale extended to cover the nonspectrals (see accompanying article “Relative wavelength metric for the complete hue cycle …”). To simplify analysis, stimuli are optimal aperture colors; their monochromatic stimuli lie between 442 and 613 nm, common boundaries with optimal compound stimuli (nonspectrals). It is shown that the wavelengths and invariant ratios of spectral constant hues can be formulated exactly (±0.5%) from the ratios of an harmonic period, which shifts wavelength with MK^?1. The formula implies this color‐constant hue cycle is isomorphic across illuminants and allows prediction of nonspectral constant hues. To identify these colorimetrically, their spectral complementary wavelengths are specified for various illuminants. This completes theglobal color constancy mechanism for the illuminant color temperature range 2800 to 25,000 K. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010     

Proposal of a new concept for color‐appearance modeling

A new type of color‐appearance model (CAM) is proposed together with its concept and flow of formulations. The topics described are: (1) The existence of two kinds of color‐appearance models, CAMs previously used and CAMs newly proposed. (2) All the CAMs, previously developed and used, do not predict color‐appearance attribute of perceived lightness of object colors under any illuminations. They may be adequately called “the model for predicting color‐appearance match between object colors under different adapting conditions.” (3) Newly improved CAMs take the Helmholtz–Kohlrausch effect in the VCC method into account. They can determine object colors with the same Tone (equi‐perceived lightness, equi‐whiteness‐blackness, and equi‐perceived chroma) irrespective of hues under reference illuminant. The newly improved models can be named Integrated CAMs. Their applicable fields are described in detail. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 113–120, 2007     

Perceptual and emotional effects of light and color in a simulated retail space

This article aims to address two aspects of lighting often treated intuitively by designers in charge of creating retail atmospheres, that is, the impact of color and light distribution, as design variables. The study comprised a controlled experiment with a repeated measure design with three directions of lighting (front, overhead, and wallwasher), as the within‐subject factor and four color combinations of the walls (yellow‐blue, magenta, gray, and green‐magenta), as the between‐group variable. The perceptual (visually) and emotional responses of 184 participants revealed the interplay between light and color on these psychological outcomes. Specifically, the results showed that the overhead direction of lighting improves the appearance of the less favored color conditions, either in terms of lack of visual complexity (monochromatic) or color itself (gray). In turn, the wallwasher lighting emphasized these attributes, differing according to visual or emotional aspects. In retailing, emotional dimensions such as activation and evaluation are desired, and they were confirmed across all the lighting and color conditions of this study. The results provide designers with certain perceptual cues regarding colors and their lighting mode to create desirable impressions and affect in retail spaces.     

Proposal of an opponent‐colors system based on color‐appearance and color‐vision studies

A new theoretical color order system is proposed on the basis of various studies on color appearance and color vision. It has three orthogonal opponent‐colors axes and an improved chromatic strength of each hue. The system has color attributes whiteness w, blackness bk, grayness gr, chroma C, and hue H. A method is given for determining Munsell notations of any colors on any equi‐hue planes in the system. A method is also given for determining grayness regions and grayness values on hue‐chroma planes in the system. It is concluded that colors with the same color attributes [w, gr, bk, C] but with different hues in the theoretical space have approximately the same perceived lightness, the same degree of vividness (“azayakasa” in Japanese), and also the same color tone. The tone concept, for example used in the Practical Color Coordinate System (PCCS), is clarified perceptually. The proposed system is a basic and latent color‐order system to PCCS. In addition, the concept of veiling grayness by a pure color with any hue is introduced. Further, relationships are clarified between generalized chroma c(gen) and grayness. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 135–150, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10234     

Use of gray system theory in product‐color planning

A quantitative evaluation method for the CIE color‐planning activity within the product design cycle is proposed in this article. The questionnaire‐based process that is traditionally employed to obtain objective color psychology tends to be time‐consuming. Accordingly, this study proposes the use of gray system theory to overcome this problem. In the CIE color system, colors are defined by three primary colors, R (red), G (green), and B (blue). Using these three principal hues with fixed equigap sequences to simulate specific basic color samples is an efficient means of investigating unicolor images on a personal computer. However, a gray relational generating operation can be used to simulate colors beyond these basic samples and to predict the corresponding membership values for semantic words. In addition, the gray clustering operation is introduced to predict the overall color image evaluation of multicolored products. The predicted evaluation results of the gray system theory and a back‐propagation neural network are both compared with experimentally verified results. The results indicate that the gray forecasting model is the more effective means of predicting the image evaluation, and therefore, the method is adopted within the color‐planning activity. Although this study takes the example of the Internet‐aided color planning of a baby walker as a case study, the proposed method can also be used on other products. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 222–231, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20009     

Long‐term memory colors of Korean and Hungarian observers

Long‐term memory colors have been discussed extensively in the literature but previous articles focused on reflecting color samples. In this work, we studied six important long‐term memory colors, skin (both Caucasian and Oriental), green grass, blue sky, deciduous foliage, orange, and banana, in the viewing situation of a self‐luminous color monitor, for two different observer groups, Koreans and Hungarians. We quantified the long‐term memory colors of both observer groups in terms of CIE L*,a*,b* values, in a given viewing situation, and estimated interobserver variability. We used a comprehensive psychophysical experimental methodology including both the method of constant stimuli and the method of adjustment. In many cases, we found significant differences (t tests, P < 0.05) between the Korean and the Hungarian long‐term memory colors. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 176–183, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20192     

Color combination criteria in Le Corbusier's Purist architecture based on Salubra claviers from 1931

We have carried out a new study of the color combinations selected by Le Corbusier in ‘les claviers de couleurs’ for the Salubra wallpaper company in 1931, by analyzing them in the Natural Color System, which allows us to understand the perceptive variables of colors (hue, blackness, and chromaticness) as well as their combination criteria. Regarding the perceptive variables, we have discussed the selected hue ranges in relation to other color proposals of Le Corbusier himself, and we have shown the extensive presence of earthy hues, or the noteworthy absence of other colors such as yellows, violets, black, and white. We have also analyzed the chromaticness of colors, which is generally low, and the blackness, also very limited. In relation to the combination criteria, we aim to find out the underlying order in the color combinations by studying the similarities and contrasts of their perceptive variables. We demonstrate graphically, by a navigable three‐dimensional model, and with statistical support, some principles in Le Corbusier's color preferences, such as the combination of colors with equal chromaticness, the search of some contrast in blackness, or the usual resource of contrasting cool with warm colors, something slightly different to the contrast of complementary colors. We have also discussed other compositional criteria held by Le Corbusier to use color in his Purist architecture, which are related to the position and proportion of the surfaces to be colored, the connotations associated to different hues, or the use of plain colors, among others. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 85–100, 2016