Research on color harmony of building façades

In this study, the 28 primary colors and 11 complementary colors suggested by Chang et al in their investigation on building colors in Wanhua District of Taipei City were taken as color samples. The two-color combination mode was adopted to obtain 308 simulation photos, and two-color harmony was discussed from the perspective of visual evaluation using psychophysical tests. This study explored building façade color harmony in the CIELAB color space, and the relationship between the color attributes (hue, lightness, and chroma) and the color harmony, and between the differences of the color attributes and color harmony. It found that a high lightness of a building's primary color is associated with a high level of building color harmony, while the color harmony is reduced when the color falls in the green or blue sector in the CIELAB color space; a greater lightness difference between building façade colors is associated with a higher level of building color harmony, while the colors are disharmonized when they tend to the blue sector in the CIELAB color space. The contribution of this study is to summarize the principles for the application of building color harmony in urban renewal, and proposed suggestions on building color harmony in the urban renewal process.     

Influence of a holistic color interval on color harmony

This study investigates how a holistic color interval, i.e., the nondirectional color difference between a pair of colors in a CIELAB uniform color space, influences perceived color harmony. A set of 1035 test color pairs displayed on a CRT was evaluated for the degree of harmony. These test color pairs consist of pairs combined from among the selected 46 test colors evenly distributed in color space. The subjects were asked to select their three preferred colors from these 46 test colors and then to evaluate the degree of harmony of the test color combinations. The color intervals (ΔE) of each test color combination were calculated and treated as values of an independent variable. In addition, the evaluated degrees of color harmony were considered as values of a dependent variable, in which statistical analysis confirmed the relationship: the degree of harmony is a cubic function of the color interval. Moreover, the plot of this relationship allowed us to identify four color intervals: roughly corresponding to the regions of first ambiguity, similarity, second ambiguity, and contrast in Moon and Spencer's model. However, our results indicated that Moon and Spencer's principles for classifying harmonious/disharmonious regions in terms of the color interval for three color attributes—lightness, chroma and hue—may be inappropriate in predicting perceived color harmony. As for the color intervals between a pair of colors considered as a function of the three attributes, the interval for lightness may have a predominant effect on color harmony, expressed in terms of a cubic relationship. Results of the study further demonstrated that the subject's choice of colors significantly influences perceived color harmony. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 29–39, 2001     

An interactive method for generating harmonious color schemes

We present an interactive visualization tool for generating color schemes that can be used by both professional artists and novice designers to improve their design efficiency. The method is developed on two color harmony principles of familial factors and rhythmic spans from conventional color theories. The interactive tool makes use of these principles for users to interactively generate colors palettes containing harmonious combinations in the hue, saturation, and lightness color space in as few steps as possible. A pilot study with 20 participants has shown that this tool provides efficient workflow, color‐scheme harmony, and intuitive interaction, demonstrating the usefulness of the method. This work contributes to an artistic‐theory driven harmonious color‐scheme generation and to interactive user interfaces visualizing color relationships. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 70–78, 2014     

Study of the color characteristics of residential buildings in Shanghai

In 2018, Shanghai launched a campaign to renovate the façade of old residential areas. With the renovation of the façade of these residential buildings, problems such as chaotic colors, dull colors, and strongly conflicting colors of walls have increasingly occurred. In this article, the color data of building samples were obtained by field investigation and the color attribute grading evaluation of residential buildings was carried out by introducing evaluation factors; thus, the evaluation results of these buildings were finally obtained. Based on the analysis of the quantity and proportion of each color attribute at different evaluation levels, the color characteristics of residential buildings in Shanghai were finally summarized. Overall, Shanghai residential buildings are “warm colored” in hue, “bright” in lightness, and “partial white” in chromaticness. The research results provide theoretical support for the forward‐looking and scientific nature of color planning for residential buildings in the future and can serve as a reference for the selection of the main colors of building walls.     

Computational color combination analysis of Papilionidae butterflies as aesthetic objects

In this study, our aim is to clarify the color combination rules of the human-preferred Papilionidae butterflies as aesthetic objects. A set of 118 butterfly images, including color polyphenism from the 47 Papilionidae species that are generally preferred by humans, was selected. These images were classified using hierarchical cluster analysis based on similarities of lightness, chroma, and hue attributes in CIELAB space, determined using histogram intersection. Then, the color distributions and combinations in each cluster were analyzed using a Gaussian mixture model and the color combination types defined in the present study. Accordingly, we obtained the following main color combination rules of human-preferred Papilionidae: (a) dominant low lightness and contrasting lightness components, (b) dominant low chroma and similar chroma components, and (c) dominant orange to yellow-green hue and similar hue components. These rules partly agree with the robust harmony principles found in previous research. We infer that the cognitive effects concerning the processing fluency through these color combination rules influence human aesthetic responses.     

An online color naming experiment in Russian using Munsell color samples

Russian color naming was explored in a web‐based experiment. The purpose was 3‐fold: to examine (1) CIELAB coordinates of centroids for 12 Russian basic color terms (BCTs), including 2 Russian terms for “blue”, sinij “dark blue”, and goluboj “light blue”, and compare these with coordinates for the 11 English BCTs obtained in earlier studies; (2) frequent nonBCTs; and (3) gender differences in color naming. Native Russian speakers participated in the experiment using an unconstrained color‐naming method. Each participant named 20 colors, selected from 600 colors densely sampling the Munsell Color Solid. Color names and response times of typing onset were registered. Several deviations between centroids of the Russian and English BCTs were found. The 2 “Russian blues”, as expected, divided the BLUE area along the lightness dimension; their centroids deviated from a centroid of English blue. Further minor departures were found between centroids of Russian and English counterparts of “brown” and “red”. The Russian color inventory confirmed the linguistic refinement of the PURPLE area, with high frequencies of nonBCTs. In addition, Russian speakers revealed elaborated naming strategies and use of a rich inventory of nonBCTs. Elicitation frequencies of the 12 BCTs were comparable for both genders; however, linguistic segmentation of color space, employing a synthetic observer, revealed gender differences in naming colors, with more refined naming of the “warm” colors from females. We conclude that, along with universal perceptual factors, that govern categorical partition of color space, Russian speakers’ color naming reflects language‐specific factors, supporting the weak relativity hypothesis.     

A geometric approach to harmonic color palette design

We address the problem of finding harmonic colors, this problem has many applications, from fashion to industrial design. The proposed approach enables the evaluations and generation of color combinations incrementally. To solve this problem, we consider that colors follow normal distributions in tone (chroma and lightness) and hue. The proposed approach relies in the International Commission on Illumination standard for representing colors and evaluates proximity. Other approaches to this problem use a set of rules. Experimental results show that lines with specific parameters—angles of inclination and distance from the reference point—are preferred over others and that uncertain line patterns outperform nonlinear patterns.     

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.     

Complexity of the color appearance of objects with nonuniform illumination

An inversion relationship is clarified between lightness and brightness, and also between chroma and colorfulness under nonuniform illumination with different illuminance levels (high and low) within the same visual field. Brightness (or colorfulness) of object color with low lightness (or chroma) under high illuminance level is perceived higher than that of another object color with high lightness (or chroma) under low illuminance level. Two color images are given for showing the inversion phenomena on brightness–lightness and colorfulness–chroma between object colors under different illuminance levels. These color images are useful for making researchers on color understand the differences in concept between brightness and lightness, and also between colorfulness and chroma. In particular, the concept of colorfulness is important, but difficult to understand. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 372–377, 2007     

Experimental determination of laws of color harmony. Part 6: Numerical index system of color harmony

The numerical index system of color harmony is intended to mark a great number of color pairs, optimally any number of existing color pairs, by a number between 0 and 100. This number expresses the extent to which a color pair is being felt harmonious by the average of people and the level of harmony content it possesses. The experiments described in this article have determined the basic data necessary to create this system. The series of the experiments have been done in two stages. The first stage, in which 24 test objects were presented to the experimental subjects, was carried out twice first in 1988–1990 and again in 2004–2006. Every test set was composed of eight compositions. The number of scores, given to each of the compositions, determined the harmony content of the color pair groups, whose members are formed from the saturated colors of different hues and from the members of the grey scale. In the second stage of the experiment, these data served as references for the experimental subjects. In the second stage, there were 192 tests. In these tests, there were different numbers of compositions each formed of different color pairs. One of the members of these color pairs was the member of the saturated color of the first experiment. The second member was always of different saturation and lightness for each of the compositions, purposefully chosen to match the saturated colors. Based on the experimental scores, we obtained a color harmony surface linked to the intersections with the coordinates in the Coloroid system. The color harmony surfaces and the distances between the related intersections indicate the harmony content of the color pair. The numerical values of these distances are called the color harmony index number of the color pair. These data make the creation of a color harmony indexing system possible, expressing the color harmony content of all possible color pairs, in the color space. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2012     

Expanding display color gamut beyond the spectrum locus

Digital video and display media are at a “sweet spot” of growth with brighter and more colorful digital projectors and displays available seemingly every day. Much more is possible in achieving brighter and more vibrant colors, colors that may even transcend our typical experience in terms of dynamic range and an expanded gamut in the perceptual sense. If the full capabilities of these technologies to produce a fuller visual experience are to be realized, new processing and encoding methodologies are required. In this article, the powers of adaptation and the CIECAM02 color appearance model are exploited to define perceptual gamut. The strategy of this methodology is, simply and in effect, to “push down” the white point of the display and demonstrate, both empirically and with a limited set of images, a striking gamut expansion in the perceptions of lightness, chroma, brightness, and colorfulness beyond the locus of pure, spectral color, and the MacAdam limits as observed with traditional display configurations. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 475–482, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20260     

Analysis of cross‐cultural color emotion

This study investigates the relationship between color perceptual attributes and color emotions, as well as the influence of different cultural backgrounds. Totally 214 color samples were evaluated on 12 emotion variables by subjects from seven different region groups in the psychophysical experiment. By factor analysis, it was found that three factors were sufficient to represent 80 “region‐emotion” variables. For each variable, there is no distinct difference among different region groups. The 12 emotion variables could be divided into four categories, namely, activity index, potency index, definition index, and temperature index. Factor scores were further calculated to study the determinants on each factor. The analysis showed that the three factors were mainly related to chroma, lightness, and hue, respectively. It was concluded that chroma and lightness were the most important factors on color emotion, whereas the influences of hue and cultural background were very limited. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 223–229, 2007     

Color appearance and color connotation models for unrelated colors

The purpose of this research is to investigate the color appearance and color connotation of unrelated colors. To investigate color appearance (i.e., brightness, colorfulness, and hue) for unrelated colors, 22 observers have answered their color appearance for 50 unrelated color stimuli using the magnitude estimation method. Perceptual data obtained by the experiment is compared with the color attributes data estimated by unrelated‐color appearance models, CAM97u and CAM02u. It is found that both models perform reasonably well but the performance of CAM02u is better than that of CAM97u. For investigating color connotation for unrelated colors, 32 observers have judged their color connotation for the 50 unrelated color stimuli using the 10 color connotation scales (i.e., “Warm – Cool,” “Heavy – Light,” “Modern – Classical,” “Clean – Dirty,” “Active – Passive,” “Hard – Soft,” Tense – Relaxed,” “Fresh – Stale,” “Masculine – feminine,” and “like – Dislike”), and semantic differential method is used for measurement. It is found that the color connotation models developed for related colors perform poorly for unrelated colors. Experimental results indicate that brightness attribute is confusing to estimate and does not affect color connotation significantly for unrelated colors. Based on the psychophysical data, new models for “Warm‐Cool”, “Heavy‐Light”, “Active‐Passive” and “Hard‐Soft” were proposed using CAM02u hue, brightness, and colorfulness. Color connotations for unrelated colors are classified into three categories, which “Color solidity,” “Color heat,” and “Color purity.” © 2013 Wiley Periodicals, Inc. Col Res Appl, 40, 40–49, 2015     

Object color preferences

In this article, we investigate how context influences color preferences by comparing preferences for “contextless” colored squares with preferences for colors of a variety of objects (e.g., walls, couches, and T‐shirts). In experiment 1, we find that hue preferences for contextless squares generalize relatively well to hue preferences for imagined objects, with the substantial differences being in the saturation and lightness dimensions. In experiments 2 and 3, we find that object color preferences are relatively invariant when the objects are (a) imagined to be the color that is presented as a small square, (b) depicted as colored images of objects, and (c) viewed as actual physical objects. In experiment 4, we investigate the possibility that object color preferences are related to the degree to which colors help objects fulfill particular functions or outcomes. We also discuss relations between our results and previous theories of color preference. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 393–411, 2013     

Considering the surround in device-independent color imaging

When viewing images, the relative luminance of the surround has a profound impact on the apparent contrast of the image. For this reason, photographic transparencies intended for projection in a darkened room are produced with an objective contrast substantially higher than that necessary for optimum reproduction as prints viewed in an illuminated surround. the dark surround causes the image elements to appear lighter and this effect is stronger for darker colors resulting in a loss in perceived contrast. This effect is also of great importance in deviceindependent color imaging since resultant images might be observed in a wide variety of media and viewing conditions. Research on psychophysical scaling of brightness and lightness and the effects of background and surround relative luminance on lightness and chroma is reviewed. the importance of this research for device-independent color imaging systems is described along with the prediction of these effects using the RLAB color-appearance model. Finally, experiments testing the use of RLAB and other color-appearance models in cross-media color reproduction applications are described.     

Three are Not Enough: An INDSCAL Analysis Suggesting that Color Space Has Seven (£1) Dimensions

Forty-five subjects, including color normals, protanomalous, deuteranomalous, protanopes, and deuteranopes, judged dissimilarities of 26 Munsell color chips chosen to span the full color space (i.e., all three parameters—hue, saturation, and lightness—were varied). Each of the 325 pairs of colors was mounted on a standard grey background board. They were presented to subjects in different random orders and were viewed under a Macbeth daylight lamp. For each pair the subject circled a number varying from 0 (for “identical”) to 9 (for “maximally dissimilar”). Fifty data matrices obtained from 45 subjects (5 were from the same subject on different dates and 2 were from another subject) were analyzed by the INDSCAL method. The three-dimensional solution yielded the “standard” three dimensions (lightness, red-green, and yellow-blue) with the classical “color circle” emerging, in a slightly distorted form, in the plane of the second and third dimensions. Seven dimensions seemed necessary to account fully for these data, however. In seven dimensions each of the “standard” dimensions is paired with a “folded” version. Accompanying lightness is a “folded” lightness dimensions, which we have called “lightness contrast.” The light and dark colors are at one end, contrasted with medium colors at the other. Similarly, “folded” red-green roughly contrasts red and green with blue, yellow, and the greys, while “folded” yellow-blue contrasts blue and yellow with red, green, and the greys. The seventh dimension, which may be artifactual, was called “split yellow.” It contrasts very brilliant (high Munsell value and chroma) yellow and orange colors with all the other colors. It is speculated that some of these extra dimensions may relate to anomalous receptor processes characteristic of deviant subjects. The INDSCAL subject space enables discrimination among all five subject types. Specifically, one of the “natural planes” (the red-green versus “folded” yellow-blue plane) of the seven-dimensional solution can be divided into contiguous and fairly compact regions, with each subject type occupying a unique region.     

Color determinants of surface stratification

Although color plays a crucial role in the demarcation of surfaces in the visual field, its role in depth perception is not well understood. Certain special effects of color on depth perception that arise from optical factors such as chromatic aberration (chromostereopsis) have been studied, but less is known about the role of perceptual factors of color in determining depth relations. The present study explores the role that the different attributes of color such as hue, chroma, and lightness play in the stratification of surfaces in depth. In two experiments, subjects manipulated specific dimensions of colors (hue, chroma, lightness, and whiteness) while making judgments of coplanarity of either two or more abutting surfaces. The results demonstrate that for surfaces to appear coplanar, their lightness has to be proportional to the natural (intrinsic) lightness of the hues. No meaningful effects of chroma, whiteness, or blackness were found in depth stratification. The results suggest a primary role of the natural lightness of hues in depth perception.     

Investigating the personality associations evoked by single colors: An exploratory study

Despite the crucial role of color appearance in forming first impressions, it is still not clear how color evokes personality associations—that is, a color‐personality association (CPA). This study aims to propose a method for quantifying the relationships between color attributes and CPAs for single colors. Specifically, we first collected the CPAs of five traits evoked by single colors (i.e., extraverted–introverted, moody–unemotional, agreeable–disagreeable, organized–disorganized, and wide interests–narrow interests) in a carefully controlled experiment. Then, multiple linear regression (MLR) analyses were adopted to predict these CPAs based on three color attributes (lightness, chroma, and hue). Our results showed that (1) the personality associations could be evoked by colors and perceived consistently by observers; (2) the relationships between the color attributes and the CPAs could be well quantified by separately conducting MLR analyses in different regions of hue (i.e., red, green, blue, and yellow regions); and (3) both lightness and chroma were significant predictors in almost all predictive models and they might have different relative importance or directions of effect when predicting the CPAs in different regions of hue, even for the same trait. This study improves the understanding of how color evokes personality associations and takes the first step toward developing the method for predicting the CPAs for multicolor combinations. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 388–396, 2017     

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