Color identification data obtained from photopic to mesopic illuminance levels

To use colors properly as an aid in visual tasks, it is necessary to know how colors are identified under various illuminating environments. In this study color identification was examined under a wide range of illuminances, from photopic to mesopic levels. Fifteen subjects named a color chip using one of the preselected color terms: red, orange, yellow, yellow‐green, green, blue‐green, blue, purple, pink, brown, white, gray, and black. The 256 color chips were selected from value planes of 4, 6, and 8 of the Munsell color space. The illuminance levels tested were 1000, 10, 1, and 0.1 lx. At 1000 lx the color chips were identified consistently by each of the color terms. At 10 lx the pattern of color identification was very similar to that at 1000 lx, though the consistency of the identification evidently declined. At 1 lx great changes in color identification occurred. By 0.1 lx reliable color identification was completely lost, though blue and red responses remained. At the lower illuminances green was replaced with blue, and red, orange, and pink were frequently confused with each other. However, the border between blue and purple was almost constant. These results provide a scientific basis for the appropriate use of colors in various illuminating environments. Also, they are useful for studies in color appearance modeling. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 252–259, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10065     

Hue,chroma, and lightness preference in Chinese adults: Age and gender differences

Recent studies have shown cultural differences in color preference. However, the color preference of people in China, which was found to have its own pattern, was yet to be studied in depth. The current study investigated color preference and the associated age and gender differences in an adult national sample (N = 1290) to provide a culture‐specific characteristic of color perception. Participants rated how much they liked each of 31 colors (four chroma‐lightness levels of red, orange, yellow, green, cyan, blue, and purple, plus three achromatic colors). We found a unique saturated color preference pattern characterized by red, cyan, and blue being preferred the most and orange as the least preferred chromatic color. The “red preference” phenomenon was observed in Chinese adults. Light colors were preferred the most in terms of chroma‐lightness level, followed by saturated, muted, and dark colors. The results of a principal component analysis of the 28 chromatic colors showed that blue‐green‐like colors (cool colors) constituted the largest proportion of color preference. The preference for orange and several dark colors increased with age, while that for bluish colors, purple, yellow, white, black, and light colors decreased. In terms of gender, women liked cyan, white, pink, and light colors and disliked red, orange, and dark colors more than men did. Our findings provide new empirical evidence about the color preference of Chinese and may offer some insight into the study of color preference and lay the foundations for future theoretical and practical research.     

Influence of basic color categories on color memory discrimination

Two color-memory experiments were performed to investigate whether observers tended to confuse colors with a smaller color difference in memory or colors in a same color-category region. We made color stimuli on a color CRT. Color difference was determined by a simultaneous color discrimination experiment. Color-category regions were obtained by a categorical color-naming experiment using the 11 basic color names: white, black, red, green, yellow, blue, brown, orange, purple, pink, and gray. The results show that two colors with a certain color difference can be confused more easily when they are in a same color category than in different color categories, and that colors identified with memory tend to distribute within their own color-category regions or their neighbor color-category regions, depending on their positions in a color space. These findings indicate that color memory is characterized by the color categories, suggesting a color-category mechanism in a higher level of color vision. © 1996 John Wiley & Sons, Inc.     

Tutorial on the importance of color in language and culture

This tutorial examines how people of various cultures classify different colors as belonging together under common color names. This is addressed by examining Berlin and Kay's (1969) hierarchical classification scheme. Special attention is paid to the additional five (derived) color terms (i.e., brown, purple, pink, orange, and gray) that must be added to Herings' six primaries (i.e., white, black, red, green, yellow, blue) to constitute Berlin and Kay's basic color terms. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 179–192, 2001     

Categorical formation of Mandarin color terms at different luminance levels

This study presents the categorical formation of a set of Mandarin color terms on the International Commission on Illumination (CIE) 1931 chromaticity diagram across six luminance levels. This article conducted a study that employed 44 native Mandarin speakers to perform a force–choice sorting task. The Mandarin color terms for sorting were determined by a free‐recall pretest and are consistent with basic color terms proposed by Berlin and Kay. The square‐sampled stimuli were generated by evenly sweeping the x–y diagram of 5, 10, 25, 50, 100, and 170 cd/m² planes. The categorical sorting results and response time (RT) measurements suggest that: (1) the concepts of green, blue, purple, and gray stably exist at most luminance levels. The voting RT for the green, blue, and purple categories is particularly short. (2) Red, orange, yellow, and pink are highly luminance‐dependent; these can be identified without difficulty only at some restricted luminance levels. (3) The chromaticity areas designated as orange, partial yellow, red, and pink are recognized as brown when the luminance level decreases. (4) Brown and gray serve as representations of two distinct tints in the low saturation condition. (5) The location of boundaries between blue and green are remarkably different than those in a similar study that employed Japanese speakers. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2011.     

Correlations between color attributes and children's color preferences

This study examined the role of color attributes (lightness and saturation) on children's color preferences for interior room colors. It also investigated children's most preferred colors among each of the five major hue families in the Munsell color system using scale‐models. Previous color preference studies have typically been done with small color chips or papers, which are very different from seeing a color applied on wall surfaces. A simulation method allowed for investigating the value of color in real contexts and controlling confounding variables. Forty‐five color samples were displayed on scale‐models to 63 children ages 7–11 years old. This study identified children's most preferred colors among each of the five major hue families in Munsell color system. It also demonstrated that saturation was positively correlated with children's preferences in the red, green, blue, and purple hue families. In the yellow hue family, interestingly, lightness has a positive correlation with preferences. Children's gender differences were found in that girls prefer red and purple more than boys. These findings lead to color application guidelines for designers to understand better color and eventually to create improved environments for children and their families. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 452–462, 2014     

Similarities and differences between male and female novice designers on color‐concept associations for warnings,action required,and signs and equipment status messages

This research examined the male and female novice designers toward color associations for the concepts used for ‘warnings’, ‘action required’, and ‘signs and equipment status’ through a questionnaire‐based study. A total of 178 Hong Kong Chinese final year undergraduate design students (89 males and 89 females) participated in the study. The test used required the participants to indicate their choice of one of nine colors to associations with each of 38 concepts in a color‐concept table, so that any one color could be associated with any one of the concepts. For both male and female groups of novice designers, chi‐square tests revealed a strong color association for each concept tested in this study (P < .05). The results showed males and females agreed on some color‐concept association stereotypes which were therefore gender neutral. The male and female novice designers had the same color associations and similar levels of stereotype strengths for 21 concepts. The nine strongest and therefore most useful color‐concept association stereotypes for both male and female novice designers were: red‐danger, red‐fire, red‐hot, red‐stop, red‐emergency, red‐error, blue‐cold, blue‐male, and green‐exit. However, the male and female novice designers had different color association stereotypes for the standby (green vs. yellow), emergency exit (green vs. red), and toxic (purple vs. black) concepts, and the strengths of the 14 remaining associations for both groups were not at equivalent levels. Overall, it is anticipated that the findings of this study will act as a useful reference for novice designers and other design practitioners to optimize color coding in the design of ‘warnings’, ‘action required’, and ‘signs and equipment status’ messages.     

Coffee cup color and evaluation of a beverage's “warmth quality”

Glass color may influence the evaluation of food and beverages as has been reported in a previous study where participants rated a cold beverage presented in a blue glass to be more thirst‐quenching than the same beverage poured into a green, yellow, or red glass. Our experiment sought to test whether container color also can affect the perceived temperature of a warm beverage. One hundred and twenty undergraduates were given warm coffee served in cups of different colors (blue, green, yellow, and red) and were asked to indicate which beverage was the warmest. Statistically significant differences among colors were found. The red cup was evaluated as containing the warmest beverage (38.3%), followed by the yellow (28.3%), the green (20.0%), and the blue (13.3%) cups. Conventional associations between warm versus cool colors are used to explain these results. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 79–81, 2014     

Categorical color constancy under RGB‐LED light sources

The light‐emitting diode (LED)‐based light sources have been widely applied across numerous industries and in everyday practical uses. Recently, the LED‐based light source consisting of red, green and blue LEDs with narrow spectral bands (RGB‐LED) has been a more preferred illumination source than the common white phosphor LED and other traditional broadband light sources because the RGB‐LED can create many types of illumination color. The color rendering index of the RGB‐LED, however, is considerably lower compared to the traditional broadband light sources and the multi‐band LED light source (MB‐LED), which is composed of several LEDs and can accurately simulate daylight illuminants. Considering 3 relatively narrow spectral bands of the RGB‐LED light source, the color constancy, which is referred to as the ability of the human visual system to attenuate influences of illumination color change and hold the perception of a surface color constant, may be worse under the RGB‐LED light source than under the traditional broadband light sources or under the MB‐LED. In this study, we investigated categorical color constancy using a color naming method with real Munsell color chips under illumination changes from neutral to red, green, blue, and yellow illuminations. The neutral and 4 chromatic illuminants were produced by the RGB‐LED light source. A modified use of the color constancy index, which describes a centroid shift of each color category, was introduced to evaluate the color constancy performance. The results revealed that categorical color constancy under the 4 chromatic illuminants held relatively well, except for the red, brown, orange, and yellow color categories under the blue illumination and the orange color category under the yellow illumination. Furthermore, the categorical color constancy under red and green illuminations was better than the categorical color constancy under blue and yellow illuminations. The results indicate that a color constancy mechanism in the visual system functions in color categories when the illuminant emits an insufficient spectrum to render the colors of reflecting surfaces accurately. However, it is not recommended to use the RGB‐LED light source to produce blue and yellow illuminations because of the poor color constancy.     

Gender difference in color preference across cultures: An archetypal pattern modulated by a female cultural stereotype

A gender difference in color preference among British participants has been repeatedly reported, in which both males and females show a preference for blue‐green colors, while females express an additional preference for pink‐purple colors. To investigate the robustness of gender difference in color preference in a different culture, we tested 81 young adult Indians from a school of design and compared them to 80 young British students in Psychology. The 35‐item International Personality Item Pool (IPIP) and Bem Sex Role Inventory (BSRI) questionnaires were also administered to explore possible links between personality traits, gender schemata, and color preferences. Results confirmed a gender difference in both cultures; participants collectively expressed a preference for cool over warm colors, while in addition females showed a preference for pink colors, with a warm bias for Indian females and a cool bias for British females. While these results extend gender difference to Indian culture and support the universality of an underlying pattern they also reveal a culture‐specific contribution essentially observed in females. In British participants, color preference was correlated exclusively with BSRI scores in females and overwhelmingly with IPIP scores in males; this gender‐specific pattern of correlation was not replicated in the Indian sample. Results point to an archetypal pattern of gender difference in color preference with a remarkable cross‐cultural similarity in men and a subtle but significant cultural difference in women whose origin is yet to be explained.     

Associations of visual forms with colors: The minor role of emotion as the mediator

Associations of colors with a wide variety of visual forms were examined. Fifty visual forms were presented to Japanese participants, who were asked to report a color suitable to each visual form out of 15 colors. Correspondence analysis was applied to the responses, and four dimensions of configurations were obtained. The first and second dimensions were related to chromaticity or hue. In these dimensions, red and orange were associated with round symmetric shapes, yellow with shapes with sharp corners, violet and purple with irregular shapes with smooth curves, and cold colors such as blue and green with forms that consisted of simple geometrical elements such as triangles, squares, and circles. The third dimension was related to L* and b* in the CIELAB color space and to the stability of visual forms. Dimension 4 was not significantly related to any of L*, a*, and b*. In another experiment, participants rated the affective impressions of the colors and visual forms on semantic differential (SD) scales. The analyses of the SD data combined with the results of the color‐form associations suggest that the role of emotional meanings of colors and visual forms in mediating the associations was rather minor, and that world‐knowledge contributed considerably to the observed color‐form associations. Kandinsky's color‐form assignment was also examined, and except for the yellow‐triangle association, the assignment was not supported.     

Hue and warm‐cool feeling as the visual resemblance criteria for iso‐CCT judgment

The hue perception and ‘warm‐cool’ feelings were investigated, in response to various lighting settings, following the adaptation to either 3500K or 5000K to compare which one—between conventional iso‐Correlated Color Temperature (CCT) and a new one based on CIE u'v′ color space—is more compatible with the visual perception. Twenty participants evaluated hue and warm‐cool feelings for 48 test lighting settings, by observing an empty gray booth. The results showed that yellow‐blue and ‘warm‐cool’ feelings are closely located around the Planckian locus, while red‐green roughly follows the line orthogonal to the Planckian locus in CIE u'v′ color space, at both 3500 K and 5000 K settings. This suggests that u'v′ color space correlates better with human perception.     

Color–concept associations: A cross‐occupational and ‐cultural study and comparison

This study used a questionnaire survey to examine color–concept associations in two occupational groups from Hebei Province in China: steel workers (n = 139) and managerial staff (n = 74). The color stereotypes held by these two groups were also compared to those held by three other cultural groups studied elsewhere (Hong Kong Chinese, Yunnan Chinese, and Americans). The participants were presented with 16 concepts and asked to choose one of 10 colors to represent each concept. The chi‐square test results showed that each concept was significantly associated with at least one color. Both the steel workers and the managerial staff primarily associated green with “go” and “safe” and red with “stop” and “danger.” The cross‐group comparisons indicated that the steel workers and the managerial staff produced stronger color associations than those produced by the Yunnan Chinese and the Hong Kong Chinese subjects, but weaker than those produced by the US subjects. Our findings build on existing knowledge of population stereotypes for color–concept associations and provide guidelines for the design of color displays and products for global users. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 630–635, 2014     

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     

Use of basic color terms by red–green dichromats: 1. General description

Abstract: In this article we present data comparing red–green dichromats' use of “Basic Color Terms” (BCTs) with that of standard trichromats. In a complementary article (Color Res Appl 2013) we use these data to evaluate two models of the mechanisms underlying dichromats' use of BCTs. There were three groups of observers—trichromats, protanopes, and deuteranopes—that each performed two tasks: “mapping” (which of these are exemplars of X?) and “best exemplar” (which is the best instance of X?), where X took the value of each Spanish BCT. The mapping task results were subjected to multidimensional scaling that revealed that dichromats differ from trichromats in the number and nature of the dimensions needed for describing BCTs' use. Trichromats required three dimensions closely related to the opponent color mechanisms (red–green, yellow–blue) and the light‐dark channel. In contrast, tridimensional solution for dichromats was difficult to interpret, whereas the fit for the bidimensional solution was very good and revealed a chromatic dimension, which did not match any of the trichromatic dimensions, and an achromatic one. There were also some error‐asymmetries (sometimes “A” was the predominant error when choosing exemplars of “B”, but not vice versa) and the groups differed in the frequency of use of some BCTs (e.g., protanopes chose more stimuli as orange than trichromats and deuteranopes). As expected, the best exemplar task produced more correct responses than the mapping task, and for both tasks, “primary” BCTs (black, white, red, green, yellow, and blue) produced better results than “derived” ones (brown, purple, orange, pink, and grey). © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 360–371, 2014     

Human brain activity and emotional responses to plant color stimuli

This study investigated how color stimuli that consisted of green foliage plants (Epipremnum aureum) with same sized area of Kalanchoe spp. plants with four different flower colors (white, yellow, pink, and red; Kalanchoe spp.) on a dark green background influenced the brain waves and emotions of 30 undergraduate students. Electroencephalography tests were performed in order to monitor the brain‐wave responses in the prefrontal, frontal, parietal, and occipital lobes in response to the different plant color stimuli. Fourteen pairs of adjectives on the semantic differential scale were used to measure emotional changes. A statistical analysis showed that all of the color stimuli correlated with some emotional keywords and physiological responses. Green plants (E.aureum) produced more positive attitudes, and brain functions were more active compared to those observed after the participants were exposed to white, yellow, pink, or red flowers on a green background. In addition, when participants looked at the green plants, the relative fast alpha power spectrum increased, indicating the involvement of improved concentration, creativity, and attention. However, optical stimuli from the yellow flowers had a positive effect on the parietal and occipital lobes, producing a high relative theta power spectrum and indicating that concentration was improved and that the subjects were happier. The choice of adjectives and the EEG patterns were weakly but significantly correlated. These results may have practical applications because green plants can be used in places where comfort and high concentration are required, plants with white and yellow flowers can be used to make a place more pleasant, and red flowering plants can be used to create a luxurious environment. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 307–316, 2014; Published online 28 December 2012 in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/col.21788.     

Recognized visual space of illumination: A new account of center‐surround simultaneous color contrast

Appearances of an object color in a space are determined by a cortical representation of illuminant for a space or the recognized visual space of illumination (RVSI). The simultaneous color contrast phenomenon on a simple center‐surround configuration can be explained by RVSI. It is hypothesized that our visual system constructs an RVSI on the surround and then that RVSI determines color appearance of the center test. If this is correct, the color contrast can be quite strong when the surround is enlarged to be an enclosed space. To support the hypothesis, color appearance of a physical gray test was measured in a green surround of various sizes. Observers were asked to do elementary color naming in the first experiment. The results showed same tendency for all observers: once the surround was extended to walls, a ceiling, and a floor of a box, perceived chromaticness abruptly increased. In other words, three‐dimensional surround evoked strong simultaneous color contrast. In the second experiment the matching method was employed with the green and other three surround colors: red, blue, and yellow. The results were consistent with the first experiment. The well‐known color contrast is thought to be a weak version of this color change. It suggested that RVSI plays an important role in the well‐known color contrast demonstration on two‐dimensional planes. © 2004 Wiley Periodicals, Inc. Col Res Appl, 29, 255–260, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20019     

Effects of nine monochromatic office interior colors on clerical tasks and worker mood

A pre- and post-between groups experimental design with nine treatment groups was conducted to determine the effects of interior office colors on subjects' clerical task performance, mood, and color preference. A total of 675 subjects participated in the study. The dependent variables were proofreading performance tasks, six mood states, and color preference. Independent variables were nine office colors, two saturation levels (high or low), two value levels (dark or light), warmth or coolness of the colors, and gender. The data were analyzed by using multivariate analyses of covariance and analyses of variance. The results showed that subjects made significantly more proofreading errors in the white office than in the blue and red offices. Females performed significantly better than males. Moreover, the saturation of the colors seemed to be a salient predictor of differences between females and males. Females indicated more depression, confusion, and anger in low-saturated office colors (white, gray, beige), whereas males reported more depression, confusion, and anger in the high-saturated office colors (green, blue, purple, red, yellow, and orange). Further, subjects revealed that they would be least likely to work in the orange and purple color offices and prefer to work in the beige and white offices. Implications for future research on the effects of colors on office worker performance and mood are discussed. © 1996 John Wiley & Sons, Inc.     

Color vision assessment‐3. An efficient,two‐step,color assessment protocol

Color vision tests and multi‐test protocols in current use often fail to detect small changes in red/green (RG) and yellow/blue (YB) color vision due to poor sensitivity. The tests also have low specificity. In this study, we examine how improved understanding of within‐ and inter‐subject variability in RG and YB color vision and accurate assessment of the differences in color thresholds between the least‐sensitive, age‐matched normal trichromats, and the least‐affected deutans and protans can be used to design an efficient color vision screener (CVS) test. To achieve this objective, we examined two extensive data sets from earlier studies and carried out new experiments to provide better estimates of within‐subject variability in color thresholds and to validate the CVS test. The data sets provide essential information on inter‐subject variability, the effects of normal aging on RG and YB thresholds, and the spread in RG color thresholds in deutan and protan subjects. A statistical model was developed to optimize the parameters of the CVS test and to predict the limits of what can be achieved in color assessment. The efficiency and repeatability of the CVS test were then assessed in 84 subjects. The results match model predictions and reveal close to 100% test efficiency. The test takes between 140 and 160 seconds to complete and has close to 100% repeatability. An efficient, “two‐step” protocol based on the initial use of the CVS test followed by full color assessment in only those who fail the CVS test is also described.