Familiar objects and memory color

Memory color for a set of eight different familiar objects has been investigated. Our results obtained with one hundred observers, eighty color samples of NCS, and two illuminants indicate that: (a) the shifts that are produced in the dominant wavelength with memory depend on the familiar object considered; (b) colorimetric purity, as a measure of saturation, of the remembered objects is not the same as that of the familiar objects; (c) in the SVF representation space, with illuminant D65 and regardless of experience in color matching of the observer, the color that was best remembered was purple aubergine and the worst remembered was brown chestnut. With the illuminant A, red tomato was the best remembered color and yellow lemon the worst. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23: 416–427, 1998     

A systematic approach of predicting color preference on the basis of gray relational grade

During the color design process, it is critical to create diversified color schemes for various consumer groups. It is also important to allow members in a design team to brainstorm for creative ideas. A theory of inspecting natural color elements was proposed in this study based on the CIE 1976 (L*,a*,b*) (CIE 1976) color space and the fuzzy c‐means clustering method. A calculation model was built to determine people's preference for colors based on a serialized system. To determine which factors affect the prediction of consumers' preference for a series of products, a gray relational color preference system was used in combination with gray relational grade so that a designer can obtain reasonable prediction results. The proposed system recommends not only the optimal colors for a product but also the optimal color scheme for a series of products.     

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.     

Near perfect visual compensation for atmospheric color distortions

Light is scattered and absorbed in the atmosphere producing visual effects that increase with viewing distance. Contrast and chromatic diversity decrease with distance, thereby modifying the way objects and scenes are perceived. Although some perceptual compensation to produce color constancy of individual surfaces has been reported, it is unclear to what extent unknown original images can be visually inferred from their distorted versions, that is, how much these effects can be discounted by the visual system. We investigated this issue with a paradigm akin to the paper-matching paradigm used in color constancy studies but with complex natural images. Hyperspectral data from 11 natural scenes were used to simulate their colors for distances up to 2000 m using a precise physical model of the effects of atmosphere. In each trial of the experiment, observers viewed the range of simulated images derived from one scene displayed on a calibrated monitor and selected the one perceived as more natural, without color distortion. Pooling data across scenes and observers showed that the image selected as more natural was very close to the undistorted one, corresponding to a simulated distance of only 2 m. These results suggest that observers are sensitive to changes in the naturalness of colors due to atmospheric effects and, crucially, can retrieve the original chromatic content with good accuracy revealing an efficient form of color constancy.     

Impact of the adapted white point and the cultural background on memory color assessments

With their inherent ability of serving as an internal reference, memory colors provide a very powerful concept in the evaluation of color rendering properties of white light sources with respect to visual appreciation. Recent results for example suggest fairly good correlations between memory-based color quality metrics and the observers' general color preferences. However, due to technical limitations in the design of the underlying psychophysical experiments, they generally lack the explicit inclusion of realistic viewing and adaptation conditions, which is supposed to have a nonnegligible impact on the model prediction performance. In addition, intercultural effects might play a crucial role in the context of memory colors. For these reasons, the current article investigates the impact of both the adapted white point and the observers' cultural background on memory color assessments in order to contribute to a better understanding of these dependencies and their interactions. For this purpose, the color appearance rating results of Chinese and German observers were collected for a selection of 12 different familiar test objects assessed under two different adaptation conditions at 3200 K and 5600 K, respectively. From the statistical analysis of the experimental data, it is shown, in accordance to previous studies, that the impact of the observed intercultural deviations is likely to be of no practical importance even though significance is found. Despite considerably larger effect sizes, the same must be concluded for the two tested adaptation conditions.     

Color memory matching: Time effect and other factors

The methods of simultaneous and successive, or memory, color matching have been compared for 10 color reference samples distributed in two groups each performed by 50 observers (25 men and 25 women). Our results, obtained with a total of two hundred Munsell color chips arrayed on ten gray cardboard panels, indicate that: (a) while by simultaneous matching the mean color differences obtained are, in most cases, lower than 1 CIELAB unit, those obtained by memory are generally higher; (b) the worst remembered colors are yellow, light green, blue, and pink, and the best remembered color is orange; (c) the influence of the delay time (15 s, 15 min, and 24 h) is significant for the remembered mean color (p < 0.03); (d) we find significant men-women differences for the remembered mean color (p < 0.05). © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 234–247, 1998     

Preference for color‐enhanced images assessed by color deficiencies

In this study, we propose color images with color enhancement for congenital red–green color deficiency on the basis of the model proposed by Mochizuki et al. [In Terrassa, Spain: Proceedings for CGIV, Springfield VA: IS&T 2008;208–213] with the aim of facilitating color customization in displays used by color‐deficient observers. Three types of color enhancements for deficiency were addressed in this study: colors were enhanced along the protan confusion line (i.e., P‐enhancement), deutan confusion line (i.e., D‐enhancement), and a line between the protan and deutan confusion lines (i.e., mix‐enhancement). We investigated the color‐enhanced image that is most preferred by each group of protan, deutan, and normal observers. Protan and deutan in this study indicate observers that are both dichromats and anomalous trichromats. Nine protan, nine deutan, and six normal observers participated in the experiment. The results showed that among the three types of color enhancements, the D‐enhancement provided the best performance for protan observers. For deutan observers, all three types provided effective enhancement, although the P‐ and mix‐enhancements were slightly better than the D‐enhancement. Our results indicated that color enhancement increases the preference evaluations of protan and deutan observers. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 234–251, 2014; Published Online 20 February 2013 in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/col.21795     

电脑测配色系统在实色涂料中的应用

简要介绍电脑测配色系统中的硬件和软件系统中的概念,详细阐述了应用于atacolor电脑测配色系统建立配色数据库的过程,及影响电脑测配色系统在实色涂料中颜色精度的因素。     

Investigation on effects of adapting chromaticities and luminance on color appearance on computer displays using memory colors

CAT02, the most widely used chromatic adaptation transform to characterize the chromatic adaptation mechanism in the human visual system, includes a factor D to characterize the degree of chromatic adaptation. This factor, however, is only determined by the luminance level of the adapting field and surround. This study was designed to investigate how the change of adapting chromaticities and the simultaneous changes of adapting chromaticities and luminance affect the degree of chromatic adaptation and color appearance on computer displays. The human observers adjusted the color appearance of various familiar objects and cubes on different display backgrounds. A higher degree of chromatic adaptation was found when using familiar objects, which was likely due to the cognitive mechanism. Both the adapting chromaticities and luminance significantly affected the degree of chromatic adaptation, with a lower degree under an adapting condition with a lower adapting correlated color temperature and a lower adapting luminance. In addition, the effect of adapting luminance on colorfulness (known as the Hunt Effect) was likely to be overpredicted in CAM02-UCS, which merits further investigations.     

Color memory in children

The methods of simultaneous and memory color matching have been studied for a set of five Munsell color samples by 50 children, 25 boys and 25 girls (ranging in age from 9 to 11 years). By comparison between this group and one of 50 young adult observers, we can deduce the following: (a) In children, as in young adults, the mean CIELAB total color difference, ΔE*_ab, in simultaneous color matching is lower than the ΔE*_ab by memory color matching. (b) Children matched reference test worse than young adults for orange, bluish green (only boys and men) and yellow green (only girls and women). (c) While men remember, independently of age and delay time, violet reference test worse than women (P = 0.02), boys remember, independently of delay time, reference test worse than girls for orange (P = 0.026) and pink (P = 0.049). (d) In short‐term memory, boys remember the reference test better than girls for bluish green (P = 0.022); girls remember yellow green reference test worse than women (P = 0.034). (e) Chroma is the perceptual color attribute that best explains sex differences, although that depends upon the reference color test considered. © 2008 Wiley Periodicals, Inc. Col Res Appl, 33, 372–380, 2008     

建筑涂料领域中影响电脑配色准确性的因素

电脑配色在涂料行业是一门新兴技术,颜色配方的准确性一直是配色师关注的问题。从色浆数据库的建立、基漆数据库的建立、颜色配方的设计、色浆与基漆的匹配、色浆/基漆批次稳定性等方面来阐述影响电脑配色精度的因素。     

Experimental determination of the laws of color harmony. Part 4: Color preference and the color harmony content

In 1956, we decided at the Budapest University of Technology and Economics to start a large‐scale experiment on color harmony. The experiments and the processing of the experimental results have been completed in 2006. These experiments, described in this article, form a study of how much are people, participating in the experiment, influenced by their own personal color preference in judging the harmony content of a composition. These experiments have utilized the results of former (1958–1969) color preference experiments and the system of color preference indexes, which were developed by the generalization of those results. Within the framework of these experiments, conducted between 1998 and 2006 there were 24 compositions, shown to the participants, at first one by one, then in pairs and at last in groups of six. They had to assess the harmony content of the compositions and award a score on a scale between 0 and 10. Each composition possessed a specific amount of harmony content according to the rules of color space, based on the Coloroid harmony threshold and verified by former experiments. In these experiments the number of elementary observations were 135 568. The people participating in the experiment were approximately equal number of men and women, from the age group between 10 and 70 years. During processing, by using the color preference numerical indexing system, we compared the results of those experiments with the color preference of a similar age group, by using color compositions, identical to the ones used in the present experiment. We have found that the sensation of the color harmony and its intensity have a strong relation to how the observers relate to colors and also their color preferences. The sensation of color harmony is also influenced by the gender and the age of the observer. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 210–224, 2009     

Preferred color gamut boundaries for wide‐gamut and multiprimary displays

Preferred chroma enhancement and its dependence on hue are studied in a two‐part experiment using a wide‐gamut multiprimary display. Earlier research showed a clear dependence on hue but was limited by the gamut of the display it employed; the present work builds on this while easing the gamut constraints. In the first part of the present experiment, a tuning task was used to refine the preference for chroma boost starting with standard‐gamut (Rec. 709) images. The overall median preferred boost is roughly 20%, but it is not uniform over hues: the preferred boost for orange, yellow, green, and cyan colors is greater than that for blue, magenta, and red colors. Dependence on image content and observer is noted, though a content‐independent chroma boost created by aggregating preference over many images performs well. An adjustment parameter for overall chroma, which incorporates the hue dependence averaged over image content, should be sufficient to handle the vast majority of interobserver variance in preference. In the second part of the experiment, various chroma boost algorithms were evaluated through a paired comparison task. The prescribed hue‐dependent chroma boost is preferred over all other variations, and all hue‐preserving chroma boost variations are preferred over both colorimetrically accurate and na??ve same‐drive‐signal renderings. The results may be applied in display design to select gamut boundaries that maximize satisfaction over the observer population. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 169–178, 2014     

Large‐field color matching functions

Color‐matching functions (CMFs) were derived with the Maxwell method for 10 subjects using two field conditions: (1) horizontally bisected circular 10° and (2) vertically bisected rectangular 102° (wide) × 50° (high). The primary set was composed of 453–533–601 nm components with a mean full‐width at half maximum of 18.3 nm; the reference field was illuminated with daylight fluorescent lamplight. Field size had a significant effect on the shape of the resulting CMFs. Under the large‐field conditions subjects were less sensitive to shorter wavelengths as characterized with the b? function and had higher sensitivities to the longer wavelengths as characterized with the r? function. © 2005 Wiley Periodicals, Inc. Col Res Appl, 31, 18–29, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20170     

建立高效的零售店调色系统

阐述了建立一套高效零售店调色系统的必要性、所需要的资源和需要进行的工作,详细讲述了零售店调色系统各部件的要求,结合中国涂料市场的现状就建立适合中国市场的零售店调色系统进行了探讨。     

Cognitive color

This report surveys cognitive aspects of color in terms of behavioral, neuropsychological, and neurophysiological data. Color is usually defined as a color stimulus or as perceived color. In this article, a definition of the concept of cognitive color is formulated. To elucidate this concept, those visual tasks are described where it is relevant: in color categorization, color coding, color naming, the Stroop effect, spatial organization of colored visual objects, visual search, and color memory. © 2003 Wiley Periodicals, Inc. Col Res Appl, 29, 7–19, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10209     

Short‐term memory of color sensation is robust against luminance distortion

It is well‐known that past knowledge affects color perception, as for example in the perception of familiar objects having richer colors. Although there have been many studies on human memory function with regard to color perception, it is not clear how color signals are treated in the early stages of human memory formation. Here, we tested whether in early memory color information is conserved without any interaction of other visual information. We found that performance of chromatic discrimination between a memorized color and a test color did not deteriorate under any contrast condition of dynamic luminance masking, and thus concluded that color signals were not disturbed by dynamic luminance signals. The results indicate that chromatic sensation per se is not modified at the early stages of the human memory system. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2011     

The metamerism potentiality of a color recipe

The weighted spectrophotometric color matching method with the optimum weighting to the spectrophotometric equations in each particular wavelength proportional to the viewing condition is applied for minimizing the color difference of instrumental color formulation of textile materials. The work is based on the one‐constant Kubelka–Munk theory. The sensitivity of a recipe to small perturbation of deviation between the reflectance of target and matched samples in the visible spectrum is determined as the metamerism potentiality of proposed recipe. Its correlation with metamerism index was also studied for some metameric pairs. Metamerism potentialities are also appraised under several light sources by using equilibrate matching strategy. The results show that the outputs of colorimetric color matching are exactly identical with the weighted spectrophotometic match under the same viewing condition. According to the numerical results for matching of 58 target samples, there is a good statistical correlation between metamerism indices and the metamerism potentialities of each recipe. Our results show that the quantitative value of the metamerism potentiality of each recipe can reasonably predict the metamerism indices of applied formulation. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 483–490, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20261