Color Research and Application最新文献

A web-hosted online experiment was previously developed to find the visual difference between four reproduction gamuts using direct magnitude estimation (Proc. IS&T 29th Color and Imaging Conf, 2021:317–322). In order to increase the size of the data set, but without overburdening observers, a modular approach was adopted. The original methodology was therefore extended across 10 linked sub-experiments to make comparisons between some 36 gamuts, which were designed to exhibit a variety of different gamut shapes, contrast ratios, and substrate colors within the constraints of a desktop display. In addition to each set of test images, a common normalization set was included in all sub-experiments in order to adjust each observer's choice of modulus to a global average observer, and thus combine the results into a larger data set. Finally, an interval scale was inferred from the normalized magnitude data using a categorical judgment approach to calculate scale values. The fitted data revealed a power function close to a square-root between the interval and magnitude scales.

Accurately assessing the color quality of printed products becomes intricate  when optical brightening agents (OBAs) are introduced in papers, as diverse interactions occur among different ink pigments and papers containing OBAs due to variations in ink formulation chemistries. Specifically, alkali-based pigments, commonly used as spot colors, are carefully formulated to ensure consistency across production batches. The presence of OBAs, which absorb ultraviolet light and emit it in the visible spectrum, significantly affects  color perception and accuracy on paper when interacting with these inks. This research marks an initial investigation into how OBAs in paper influence the color accuracy of five distinct alkali-based spot color paste inks using a Little Joe ink proofer. The research examines the physical, optical, and colorimetric  characteristics of two paper samples-one with OBA and one without- and analyzes the colorimetric changes occurring during the ink drying process. The results indicate that reflex blue, purple, and violet spot colors achieved acceptable delta E (ΔE₀₀) value of below 3 on non-OBA paper, with rubine red being on the borderline at 3.1 after 48 h. In contrast, purple, rhodamine red and violet achieved acceptable ΔE₀₀ below 3 on high OBA paper. The distinct behavior exhibited by certain inks led to the conclusion that achieving a consistent  proofing procedure across diverse alkali-based ink formulations is impractical.

In this exploratory study, we delved deeply into the intricate interplay of color choices within AI-generated and human-designed posters, analyzing a sample of 120 instances from each category. While it is suggested that human designers may integrate cultural, emotional, and situational contexts into their creations, AI models largely base their selections on vast datasets and pattern recognition. Although AI exhibited prowess in replicating established design parameters, the study underlined the importance of critically assessing its outputs. The quantitative analysis illuminated overarching similarities in primary color selections. However, the AI's diversity in color remains less concentrated than that of human, suggesting a gap in the AI's capacity to match human expertise in color proportioning and distribution. As AI continues to evolve, it is crucial to discern its capabilities and potential limitations in the design domain, ensuring it augments human creativity rather than supplanting it. Notably, the research refrains from seeking human validation, aiming instead for an objective, data-driven reflection on the convergences and divergences between AI-generated and human designs.

We present the results of a series of three brightness-matching experiments which include a key refinement in this established psychophysical method. Constraining the chroma difference between pairs of stimuli matched in brightness allows us to use a novel calculus-based approach to building a model of the brightness of chromatic visual stimuli and the Helmholtz-Kohlrausch effect. The proposed models, compatible with the CIECAM16 color appearance model and CIELAB color space, are compared to other models of the Helmholtz-Kohlrausch effect on these data and other past brightness-matching studies. The proposed CIECAM16-based model demonstrates the overall best performance on predicting the Helmholtz-Kohlrausch effect in four newer data sets but overpredicts the weaker effect reported in three older data sets. The potential experimental factors in this divide between new and old studies are also discussed.

Tristimulus values and chromaticities, which are derived using the color matching functions (CMFs), are commonly used for color characterization, calibration, and specifications, with the stimuli having the same values believed to have the same color appearance (i.e., metameric match). Many studies, however, found that the stimuli having the same tristimulus values do not appear the same (known as metameric failure) due to the failure of CMFs in accurately characterizing the color matching mechanisms. Most past work investigated the performance of different CMFs through color matching experiments, with a smaller chromaticity or calculated color difference between the reference and test stimuli suggesting a better performance. Such differences, however, may not accurately characterize the performance of the CMFs, since the color spaces or chromaticity diagrams may not be uniform, in terms of the threshold of noticeable color difference. In this study, the human observers evaluated the perceived color difference between pairs of stimuli, which were calibrated to have the same tristimulus values calculated using the CIE 1931 2° CMFs, with two sizes of field of view (FOV). The results clearly suggested that the stimuli having the same tristimulus values may not always appear the same, which depended on the primaries and the FOV. More importantly, the results clearly suggested that the chromaticity differences from color matching experiments may overestimate the metameric failure, especially when the color differences were small.

New photoluminescent materials have numerous possibilities in many different areas from technological applications to contemporary glass art and design, encouraging the development of new forms and products. Glass luminescent materials, known for their exceptional durability and recyclability, position glass as an ideal solution for fostering a more sustainable future. In recent years, white luminescence in glass and ceramics has been the subject of several investigations about its possible application in white light-emitting diodes (WLED). Color coordinates and CIE chromaticity diagrams serve as valuable tools to represent and define the range of luminescent colors achievable in a particular composition. These aid in understanding wheter a composition can be used to produce white luminescence or various other colors.  In this study, a soda-lime silicate glass composition was doped with a mixture of different lanthanide oxides to increase the luminescence color palette. The same glass sample can also present different colors by changing the excitation light, allowing higher tunability of luminescent colors. It was effectively demonstrated the extensive spectrum of colors produced, which was represented through luminescence color coordinates for all synthesized glasses. Moreover, the possibility of detecting if an excited state process is occurring was studied by calculating the lanthanides factors and comparing them with those used in the glass synthesis. Nevertheless, it is shown that the energy transfer process has to be significant to influence the color coordinates and the calculation of the factors.

Studies on the color category PURPLE yielded inconsistent category boundaries, focal colors, and color-emotion associations. In French, there are at least three color terms referring to the shades of purple, potentially weighing on these inconsistencies. Thus, we tested the semantic breadth and richness in semantic meaning of violet (basic term), lilas (non-basic), and pourpre (non-basic). We collected free associations in 274 French speakers from Algeria, France, and Switzerland, yielding 2079 responses, of which 436 were discrete and 275 were unique. Frequency analyses and semantic coding supported the basicness status of violet in French, within a hierarchically structured semantic system. Moreover, the meaning of the three terms was not synonymous. Violet had the most abstract meaning. Lilas had the narrowest meaning, mainly referring to Natural Entities. Pourpre seemed close to RED. We found no differences between the countries. Future studies should extend this approach to other languages and other color terms.

Previous studies have offered multiple explanations for the causality of color preference but no consensus has been reached. In this study, we propose an alternative explanation that the memory colors of familiar objects, especially food colors of humans can induce color preferences. We conducted two experiments. In Experiment 1, the memory color experiment, we asked participants to rate the similarity between presented color samples and memory colors of five familiar fruits and vegetables in Japan; we then calculated the location of the colors in the CIELAB color space that looked most similar to the remembered objects using the bivariate Gaussian function. In Experiment 2, the color preference experiment, color variations were created based on the memory colors obtained from Experiment 1. A different group of participants rated their preference for each color variation, then we applied regression analysis to these ratings. We observed two types of regressions between preference ratings and distance to memory colors: (1) for colors from red to green that represent the food colors for primates, color preference increased when the color was closer to the memory colors of the fruits and vegetables found in Experiment 1; and (2) for blue and purple colors, colors were preferred when they became bluer. We suggest that the evolutionarily acquired mechanism of color preference derives crucial cues from our ecological environment. Therefore, the mechanism produces the same color preference trend among people who grow up in similar environments, for example, environments containing the same fruits.

This study examined whether people's ability to recognize facial expressions is affected by manipulating the color of their lips or eyes. Participants comprised 100 Chinese adolescents (mean age = 13.79 years, SD = 1.06). The stimuli consisted of happy, neutral, and sad facial expressions, which were manipulated to have different lip or eye colors. Participants reacted to the images by indicating their perceived emotion. Performance speed and accuracy were assessed during the experiment. Results indicated that for happy and neutral expressions, the use of color significantly reduced reaction times, while the accuracy remained unchanged. Conversely, for sad expressions, reaction time was not affected by color, but all color categories exhibited reduced accuracy.