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     

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     

Analyzing the natural color system's color-order system by using a nonlinear color-appearance model

The Natural Color System (NCS) is analyzed by using a nonlinear color-appearance model. Perceptual uniformity was examined for each of the NCS attributes of blackness (s), chromaticness (Cr), and hue. Some nonuniformities were found in chromaticness and hue spacing, which were probably the result of the assessing and scaling method used in developing the system. In addition, a colorimetric interpretation is given to a principal plane in the NCS consisting of the colors with (s,Cr) = (50,0) and (0,100). The colors with (0,100) have different values of Y for different hues. Based on the analysis, a method is developed to predict the NCS attributes from the values x, y, Y of an object color by using the nonlinear color-appearance model. The present analysis clarifies the importance of the NCS system in studying the color appearance of object colors.     

Interrelation of the natural color system and the munsell color order system

The CIE tristimulus values of the aim points of the Natural Color System (NCS) were converted to Munsell notations using a computer program. The values so converted were those from the four elementary hues R, Y, G, and B, and the intervening hues for which full pages of colors exist in the NCS Colour Atlas. The resulting notations were plotted on Munsell Value-Chroma and Hue-Chroma charts and analyzed for several features of interest, for example the locations of the points with 100% chromaticness and the relative spacing of the hue circles. Analytical equations are presented relating Munsell Chroma and NCS chromaticness, and Munsell Value and NCS blackness, for both achromatic and chromatic samples. Such analytical relationships could not be derived between the hues of the two systems, since a relatively wide range of hue in either system corresponds to constant hue in the other. This range appears to include both systematic and random components that must be removed before analytical relations between the two hues can be derived.     

Whiteness,chromaticness, and blackness symmetries for CIELAB,with a numerical example

Whiteness, chromaticness, and blackness are defined for CIELAB. These NCS‐like color attributes offer an alternative to lightness and chroma for describing color. Their hue‐preserving symmetries are derived for tristimulus color space. A numerical example provides what theory predicts are visually uniform sequences of colors with constant lightness, whiteness, chromaticness, or blackness. Numerical approximation is unnecessary. Such sets of symmetric colors in one hue are visually interesting, and useful for computer aided design. The appropriateness of such attributes for CIELAB is briefly discussed. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010     

Lightness perception of chromatic object colors

A hypothesis is proposed to predict the perceived lightness of chromatic object colors, which is well known as the Helmholtz-Kohlrausch effect or the lightness-reflectance ratio effect (L/Y effect). The hypothesis is, “When two chromatic object colors with different hues have the same values for each of three attributes (whiteness, blackness, and chromaticness), the two colors have the same perceived lightness, including a chromatic-component contribution.” The hypothesis is tested by two kinds of experiments: perceivedlightness matching using the NCS Color Atlas, and chromatic tiles determined by Wyszecki. Both results strongly confirm the hypothesis. Further, contour lines of constant L/Y ratios are estimated, and are very similar to those reported previously.     

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     

Investigation for the color samples with equi-depth in Natural Color System

The color depth, an important attribute of color, can reflect the amount of dye partly, which has important functions on the evaluation of color-fastness and strength of dyes, dyeing effect of fabric, computer color matching, and so on. Natural Color System, an internationally accepted color system, orders colors by three parameters (blackness, chromaticness, and hue). The color depth has not been specified within the Natural Color System. This article tries to find the regularity of the sample with equal-depth in Natural Color System. Firstly, 1950 color samples in Natural Color System were measured using an X-Rite Color i7 Spectrophotometer, and their color depths were calculated by five color depth formulas. Then, trend analysis and mathematical modeling methods were used to achieve the connection between the color depth and the notations of Natural Color System basing on color depth theories. Results show that, in Natural Color System, the color samples with the same distance to pure white do not have equal depth; but the color samples with the same nuance (equal blackness, whiteness and chromaticness) have broadly equal color depth, and their average coefficient values are lower than that of Society of Dyers and Colourists Standard Depths. Besides, regressive formulas were built, with which the color depths of any chips in Natural Color System can be calculated broadly by their notation.     

A test of uniformities in the OSA‐UCS and the NCS

In the OSA‐UCS (Optical Society of America–Uniform Color Scales), except for colors on the boundary of the three‐dimensional solid (L, j, g), each color is surrounded by the 12 nearest neighboring colors that are supposed to be perceptually equally different (local uniformity). In the Swedish NCS (Natural Color System), colors are arranged so as to gradually vary in each of the three perceptual attributes: hue, ?; blackness, s; and chromaticness, c. The gradual change in an attribute may correspond to change of color difference from one to the next with a constant step (local uniformity). In each of these color‐order systems, the uniformity was tested by a color‐difference formula d? based on color‐component differences. When a coordinate is fixed (e.g., j in OSA‐UCS, or c in NCS), d? for neighboring pairs turned out fairly constant. However, systematic differences were found between d? in one coordinate and d? in another coordinate. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 277–283, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10162     

Effects of hue,saturation, and brightness on preference

A study was done to investigate preference responses for foreground–background color relationships. To do this, 123 university undergraduates in Ankara, Turkey, were asked to view eight background colors selected from HSB color space on which color squares of differing hues, saturations, and brightnesses were presented. Subjects were asked to show the color square they preferred on the presented background color. Findings showed that colors having maximum saturation and brightness were most preferred. Blue was the most preferred hue regardless of background. The findings for preferences for foreground–background color relationships are also included in this article. © 2002 Wiley Periodicals, Inc. Col Res Appl, 27, 199–207, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10051     

Color characteristics of Beijing's regional woody vegetation based on Natural Color System

Seasonality is a typical characteristic of Beijing's regional vegetation, and plant color is one of the most prominent visual factors of vegetation dynamic. In this research, we explored the composition and dynamic characteristics of plant color in Beijing's urban vegetation, involving the analysis of overall characteristics and respective features of leaf, flower, and fruit colors. Color data was collected from 177 woody plant species in Beijing Botanical Garden, spanning their annual life cycle, and identified with the colorimetry of the Natural Color System (NCS). Correlation and regression analyses were applied to reveal the temporal dynamic features of overall plant color richness. Cluster analysis was applied to categorize tree species based on typical colors of various plant organs. Color richness and color dispersion were introduced as two factors to measure color diversity of various tree species, applied in species evaluation by sorting and principal component analysis (PCA). Color dispersion of three‐dimensional NCS data was measured with a modified SD based on the calculation of mean spatial distance in the NCS space. Main results are as follows. The first part is plant color composition. The composition of all plant colors contains 862 NCS color species, 20 blackness species ranging from 3 to 90, 20 chromaticness species ranging from 0 to 90, 35 hue species ranging from G10Y‐B90G, and N. The second part is temporal dynamic of overall color richness. Leaf color richness and total color richness are significantly positively correlated with pentad (5‐day) sequence; flower color richness is significantly negatively correlated with pentad sequence; and fruit color richness first increases and then decreases over time. The third part is cluster analysis of tree species. Based on typical growing‐leaf color, various tree species were clustered into 6 categories; based on typical senescent‐leaf color, various tree species were clustered into 6 categories; based on typical flower color, various tree species were clustered into 15 categories; based on typical fruit color, various tree species were clustered into 7 categories. The fourth part is color diversity evaluation of various tree species with PCA. According to the PCA of flower‐leaf color diversity, the species with higher leaf color diversity and higher flower color diversity include Cotinus coggygria, Lagerstroemia indica, and Amygdalus triloba; the species with higher flower color diversity and lower leaf color diversity include Campsis radicans and Tamarix chinensis; the species with higher leaf color diversity and lower flower color diversity include Acer ginnala and Crataegus pinnatifida; the species with lower color diversity both for flower and leaf colors include Fontanesia fortune and Gleditsia sinensis. According to the PCA of leaf color diversity, the species with higher leaf color diversity in both leaf growth period and leaf senescence period include Diospyros kaki, Lagerstroemia indica and Paeonia suffruticosa; the species with higher leaf color diversity in leaf growth period and lower leaf color diversity in leaf senescence period include Amygdalus persica ‘Atropurpurea’ and Prunus virginiana ‘Canada Red’; the species with higher leaf color diversity in leaf senescent period and lower color diversity in leaf growth period include Quercus palustris, Armeniaca sibirica, and Metasequoia glyptostroboides; the species with lower leaf color diversity for the whole leaf development period include Gleditsia sinensis and Swida walteri.     

Analyzing a decade of Colors of the Year

The Color of the Year was first introduced by Pantone in 2000, and recently (the last decade) we saw the trend of introducing a Color of the Year being picked up by more and more companies. Paints and coatings companies typically select their colors of the year by extensive research by designers and trend experts, resulting in a plurality of colors being introduced as Color of the Year, every year. In this article, we collated colors of the year of 15 different paints and coatings companies published in the past decade and we show that most colors of the year can be described as neutral or off‐white color (ie, the median value for NCS Chromaticness is low, 20%) although occasionally colors of the year have high NCS Chromaticness. We demonstrate that the distribution of colors of the year follow a certain narrative from year to year: The average Lightness and Chroma (averaged over all companies, per year) appear to follow a wavelike pattern, where the average Lightness appears to repeat itself every ~8 years and the average Chroma approximately every 4.5 years. Similarly, we can see a cyclic pattern in the hue: From mostly yellowish red or greenish blue in 2015, towards predominantly blue in 2017, to a wide variation in hues in 2020 suggesting a fragmentation in colors of the year preferences. In addition, we demonstrate that the colors of the year differ significantly from what can be expected if the colors would have been selected randomly. This could reflect the fact that paint companies use similar raw data to identify their color trends.     

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     

Experimental determination of laws of color harmony. Part 3: Harmony content of different hue pairs

At the Budapest University of Technology and Economics in 1956, we decided to start large‐scale experiments on color harmony. The experiments and the processing of the experimental data were completed in 2006. The experiments described in this article were based on a long established experience that harmony content of different hue pairs greatly differ from each other. The vast majority of former research activities on the subject of color harmony narrowed down mostly to investigations of saturated color pairs. Color samples of our experiments have been defined within the color space of the Coloroid color system, built on harmony thresholds. The compositions, prepared for the experiments, always consisted of two saturated hues and three low saturation colors of each hue at varying brightness, making it a total of eight colors. Within the framework of the experiments, 48 hues were used. Out of these, each of the 24 was formed into composition pairs with the remaining 48 hues, forming a total of 852 compositions. The paired‐comparison experiments were conducted with the use of the compositions prepared by collage technique. Color samples made of painted paper, between 1980 and 1985, have been repeated between 2002 and 2006 with the same color selection but with computer‐generated pseudorandom patch system compositions. It has been established that harmony content of hue pairs can be expressed by the relative angle of their hue planes in the Coloroid color space. The harmony content of hue pairs exceeds that of other pairs, when this angle is below 10°, between 30° and 40°, between 130° and 140° or near to 180°. Those color pairs of which hue planes are between 60° and 90° to each other in Coloroid color space, exhibit the least harmony content. © 2008 Wiley Periodicals, Inc. Col Res Appl, 34, 33–44, 2009.     

Using symmetry to understand the attributes of color

The common attributes of color are distinguishable by their symmetries. Hue, saturation, chroma, chromaticness, whiteness, and blackness symmetries are discussed. Symmetries are generally not sufficient to specify unique formulas for color attributes, nor are they an endorsement of color model accuracy. However, symmetries do provide constraints for valid formulae, which are useful even when symmetries are only approximate. They also provide an alternate conceptual understanding of color attributes that differs from standard color science definitions. Symmetries provide a simplified framework for calculating groups of colors that share color attributes. Color models examined include the Hunt Model, a simple color model (SCM), various CIE color spaces, and IPT. A general functional form describes symmetries and scaling laws for many color models, and exceptions are discussed. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 27–44, 2008     

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     

A novel method for assessing the chromatic integration of architecture in the Ksourian landscape of M'zab Valley,Algeria

Ksour are original architectural models of fortified villages located in the north of Africa. They offer, through their urban and natural visual sceneries, specific visible features that we name them Ksourian Landscapes. The present research, accordingly, addresses an investigation; relying on a new methodic perspective, of the chromatic character of the Ksourian landscape of M'zab valley in Algeria which is listed as an UNESCO World Heritage Site. Using the Natural Color System (NCS), a natural palette (NP) has been conducted; encapsulating 12 representative colors from the natural landscape of the site in congruence with a second palette (human settlements palette), which includes around 16 colors from the urban landscape of the Mozabite Ksour. The primary purpose of this research article aims at identifying perceptual similarities between the two palettes after comparison; which relies upon the NCS nominal identities (blackness [s], whiteness [w], chromaticness [c], yellowness [y], and redness [r]); and the NCS relation identities (hue [φ], saturation [m], delta [δ], and beta [β]). Graphical representations of these comparisons are demonstrated in the NCS triangle and the NCS 3D color space. We have demonstrated through our experimental outcomes the strong chromatic integration of the urban settlements in their natural landscape, the original chromatic character as being a constituent of the heritage values of the Mozabite Ksourian landscape, as well as its possible use in the urban restoration processes.     

Visual customization: Diversity in color preferences in the automotive interior and implications for interior design

Evolving multimodal mobility needs influences established human–product relationships and requires a deeper insight into color preferences for car interiors. Hence, a study was conducted in which 204 members of a web contest created 1,265 designs. After a peer‐evaluation process, 53 most‐appreciated and 34 least‐preferred interior color compositions were identified and compared to identify patterns in color choices. Besides, visual lightweight design by layering of large interior components such as the seat, a modest use of color and patterns accompanied by repetition and the framing of the entire interior to create a feeling of spaciousness were found. Additionally, differences in the type of color between most and least favored color designs were found. Brown and beige occur more frequently among the top‐ than the worst‐rated designs. Larger surfaces are favored in lighter hues and smaller components in darker hues.     

Color preferences for different topics in connection to personal characteristics

Studies on color preferences are dependent on the topic and the relationships with personal characteristics, particularly personality, but these are seldom studied in one population. Therefore a questionnaire was collected from 1095 Dutch people asking for color preferences about different topics and relating them to personal characteristics. Color preferences regarding different topics show different patterns and significant differences were found between gender, age, education and personality such as being technical, being emotional or being a team player. Also, different colors were mentioned when asked for colors that stimulate to be quiet, energetic, and able to focus or creative. Probably, due to unconsciousness of contexts, many people had no color preference, a result that in the literature seldom is mentioned. Blue was the overall favorite color; however, most males chose for blue (25%) while most females had no color preference (18%). Black was the overall favorite color for clothing, mainly chosen by females (40%), while males primarily chose blue (27%). For building interiors subjects preferred white. For moods, subjects preferred white for being quiet or being able to focus, red for being energetic and had no color preference for being creative. It is concluded that color preferences are dependent upon the topic, and personal characteristics. The findings are important for architects, interior designers, fashion designers and product designers to have a basic idea of preferred colors for different objects by different types of people. © 2013 Wiley Periodicals, Inc. Col Res Appl, 40, 62–71, 2015     

Hue,saturation, lightness,and building exterior preference: An empirical study in Turkey comparing architects' and nonarchitects' evaluative and cognitive judgments

This study investigated architects' and nonarchitects' evaluative and cognitive judgments of color on building exteriors. Thirty architects and 30 high school teachers living in Izmir, Turkey participated in the study. The experiment had two phases. First, participants viewed eight images, in which the color of a building exterior was manipulated with hues selected from HSB (hue, saturation, and brightness) color space. Participants were then asked to rate each image on 7‐point semantic differential scales measuring preference (like–dislike), arousal (arousing–sleepy), naturalness (natural–artificial), and relaxation (relaxing–distressing). Second, participants viewed the same building in nine saturation and lightness levels for each hue and picked the most preferred lightness and saturation level for each hue. Findings showed that for a building exterior: (1) yellow and blue were the most liked colors, (2) some hues were rated as more arousing, more natural, and more relaxing over the others, (3) gender had an effect on color preference and semantic ratings of naturalness and relaxation, (4) architects and nonarchitects differed in their color preference and semantic ratings of arousal and naturalness, and (5) full bright and moderate to low saturated colors and full saturated and moderate to high bright colors were preferred more. The results have practical implications for architects and urban designers. A successful coloration of a building exterior may increase its use frequency and economical value. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 395–405, 2008