Color Research and Application最新文献

Research suggested that color vision evolved for the purpose of seeing skin color modulations signaling emotion or mood. Hence people want to find the connection of the cone sensitivities with the skin spectral reflectance. In this article the W and V shapes based on skin spectral reflectance measured at different positions and from different ethnic groups (Kurdish, Caucasian, Thai, Chinese) were investigated. First, it was found that the measured skin spectral reflectance from all body positions and ethnic groups have a V shape between 400 and 450 nm and a W shape between 520 and 610 nm. The W and V shapes from the measured skin spectral reflectance are clearly different from those from the spectral reflectance generated from the physical model. The V shape and W shape do not exist with spectral reflectances measured from artificial skin color. Second, it was found that the wavelengths where the left trough assumes for the W shape are different from the wavelength where the M cone peaks, and the wavelengths where the central peak of the W shape assumes are different from the wavelength where the L cone peaks, which are different from the results from literature. Third, it was found that the skin spectral reflectance varies with body positions and ethnic groups. The W shapes turn to be a “U” shape for the spectral reflectance measured at back of the hand and inner forearm positions. The spectral reflectance measured from Kurdish starts decreasing for each body positions for wavelength greater than 700 nm, which is clearly different from the spectral reflectance measured from the Chinese and Caucasian ethnic groups. The findings of this paper are valuable for improving the physical model for generating skin spectral reflectance, reconstructing skin spectral reflectance based on image, identifying human skin color from spectral imaging and rendering of human skin color in computer graphics.

When we enter a dark place, such as a tunnel, from a bright exterior, our visual sensitivities take some time to adapt to lower light levels. However, there have been few reports on how quickly luminance and chromaticity discrimination sensitivities recover in this situation. This study aims to quantify the time course of discrimination sensitivity for luminance and chromaticity directions after an abrupt decrease in background luminance. In each trial, the background luminance was decreased from 100 to 1 cd/m². Subsequently, one target and three reference stimuli of different colors were presented under four stimulus-onset asynchrony (SOA) conditions. The participants discriminated the target stimulus from reference stimuli. The results showed that discrimination sensitivity was the lowest right after the background luminance changed and gradually improved with SOAs. The sensitivity decreases differed across color directions, with the greatest decrease in luminance, a moderate decrease in S−(L + M), and a negligible change in L−M. However, statistically significant differences were observed only between luminance and L−M, suggesting that the sensitivity decrease after the abrupt decrease in background luminance did not significantly differ between the chromaticity directions. We speculate that these results stem from the interaction between chromatic perception and luminance adaptation, and possibly from rod intrusions.

This study aims to identify the color preferences of ancient Egyptian paintings and their cultural and historical reasons through color analysis, and consequently introduce a color collection of ancient Egyptian painting colors for color matching of modern digital images. A total of 134 original and 168 replica/repair painting samples were selected from the digital repositories of various authoritative museum collections, focusing on painting patterns formed on object surfaces using coloring agents. The collected samples, spanning from the Ancient Kingdom of Egypt to the Greco-Roman period, encompass distinct types of ancient Egyptian paintings. The diversity and chronological distribution of these samples suggest that the color use in ancient Egyptian paintings is closely linked to the burial culture, coffin decoration, religious beliefs, and policy changes. Color analysis of the collected samples using the natural color system revealed that the predominant colors in ancient Egyptian paintings tend to be in the red and yellow spectrum, while the blue, green, and purple spectrum is relatively less prominent. This can be attributed to the historical development of colors, the scarcity of mineral resources, and the symbolic significance of colors in ancient Egyptian culture. Finally, a collection of ancient Egyptian painting colors was selected from extracted colors based on color differences to reflect the color characteristics of ancient Egyptian paintings. Furthermore, the construction method of color palettes with different thematic images and the practical application of these palettes in digital patterns using the proposed color collection were demonstrated to offer a reference for designers.

This research delves into the development of the Urban Color Plan for Ledro Valley, in Italy. Urban color, encompassing both natural and built elements, plays a crucial role in spatial perception, impacting an individual's cognitive and sensory experiences. This study aims to address the complexity of color planning by an operational method grounded in scientific research. Through the analysis of existing color plans and the study of this specific case, the paper proposes a methodology which emphasizes scientific scrutiny by encompassing factors like historical context, social aspects, environmental influences and a chromatic and material facade survey. The research outlines the multifaceted scales of intervention, ranging from urban mapping to material quality considerations. The Ledro Valley case study exemplifies the application of this methodology, revealing the challenge in harmonizing the diverse historical-political realities of this Valley. The results showcase a flexible color plan that unifies the territory while still preserving the distinct identities of individual previous municipalities, demonstrating the plan's adaptability and potential for enhancing the overall urban environment.

Digitizing motion picture films is a crucial aspect of archival practices. Nevertheless, the primary purpose of this process is to convert analog film into a digital signal suitable for recording back onto film. Thus, the most popular color film system encoding, such as Cineon or Academy Density Exchange (ADX), may present some limits for the preservation and restoration practices. In this paper, Cineon and ADX systems are summarized and analyzed, and an experimental application conducted on modern cinematographic film scanners has been made to evaluate the integration of these encoding systems into these devices. Results have been examined and discussed to underline the constraints and possibilities of these color encoding systems for archival purposes.

The performance of color matching functions (CMFs) is important to color specification and calibration. In comparison to the great number of studies focusing on the effect of primary set, few studies focused on how observer age and field of view (FOV) jointly affected the performance of CMFs. In this study, a color matching experiment with three different primary sets, which were carefully selected based on our previous study, was carried out by two observer age groups under four FOVs (i.e., 2°, 4°, 8°, and 13°). The results suggested that the observer age had a more significant effect than the FOV, and the change of the FOV did not introduce a systematic trend to the color matching results. Neither the CIE 1931 2° nor 1964 10° CMFs were found to accurately characterize the color matches. The CIE 2006 CMFs with the FOV set to the experiment setup also did not have good performance. On average, the CIE 2006 2° CMFs were found to have the best performance, without considering the effects of the observer age and FOV.

Our previous work revealed that the vision-based color representation of congenitally color-deficient observers (CDOs) was mostly C-shaped bending at yellow and blue that differed from circular shape of the observers with no color vision deficiencies called CNOs in the study. In this study, the color-name-based internal color representation was investigated for the same observers and its relation to the vision-based color representation was examined. First, psychological difference of all combinations of 10 color names corresponding to the Munsell basic hues was rated using a 5-point scale. The distances of all pairs of CNOs and the CDOs agreed well with each other, in contrast to the distinctive differences in the vision-based color representation. Second, color-naming was conducted to the 10 color chips for each of high and medium chroma to link the vision-based and color-name-based representations through the test stimuli. For the high chroma chips, color naming property of the CDOs was similar to that of the CNOs. In contrast, CDOs showed distinctively larger intra- and inter-observer variabilities than CNOs for the medium chroma chips. The difference between two color chips was estimated using the results of the color naming and extended color-name difference ratings which is called “color-naming difference.” No systematic relationship was observed among the color-chip difference, color-name difference, and color naming difference in individual comparisons. It indicated that the color-naming difference is greater for the pairs including YR/Y/GY versus G/B, and vice versa for the pairs consisting of BG, B, PB, P, and RP. These suggest the followings; first, CDOs seem to utilize lightness difference strategically in the visual assessment, second, psychological differences among “blue,” “green,” “purple,” or “gray” are distinct for CDOs although the color chips given those names in our experiment appear close.

A color rendition chart, the preferred memory color (PMC) chart, has been produced. It comprises 30 colored patches, divided into three groups: preferred memory colors, reference color-gamut colors, and a gray scale. The main purpose of the new chart is to enable users to produce satisfactory preferred color reproduction using digital cameras, displays, and printing systems. The methods used to develop the various colors, and the color specification of each color are presented. Finally, several potential applications of the chart for the characterization of imaging devices, for the evaluation of image color quality, and for the calculation of color rendering indices for lighting are suggested.

Plastics are commonly produced and sold in pellet form due to their superior handling characteristics. However, due to their small size, it is often impractical, if not unfeasible, to determine the transmittance of a single pellet instrumentally. Moreover, such measurements may be highly variable. Therefore, translucent films of certain thickness, known as plaques, are commonly molded to enable instrumental determination of their transmittance. These plaques, however, are not needed beyond the quality control process while they add a costly step to the production process. In this study, we test a method, based on the layer theory, that enables the estimation of the transmittance spectra of nearly transparent plastic plaques from the reflectance measurements of their pellet counterparts. The comparison of the estimated transmittance spectra of pellets versus measured transmittance of plaques shows the RMSE ranging from 0.37%–1.80%, with a color difference, CIEDE2000(1:1:1), of 0.07–0.48, thus validating the applicability of the method.

The papermaking, packaging, and printing industry are actively seeking sustainable material alternatives to address growing concerns about environmental consciousness and finite resources. Synthetic latex, a frequently utilized binder in paper coating formulations, present difficulties due to their dependence on fossil fuel resources and their reduced recyclability in comparison to eco-friendly sustainable products. In this study, synthetic latex was replaced with a starch-based nanoparticle (starch NP) binder at a 1:1 ratio in a coating formulation. Printing trials to assess colorimetric characteristics was made using electrophotography (EP) printing, given the current upward trajectory and expansion of EP technology into the label, packaging, and folding carton sectors. The in-depth investigations reveal that incorporating starch NP binder result in improved optical, color, and dot characteristics. Moreover, it maintains consistent and comparable coefficients of friction. Partial replacement of synthetic latex with the starch NP binder yields significant enhancements in surface roughness and text quality. Importantly, the starch NP binder not only improves the dielectric relaxation properties of the paper and enhances toner transfer but also accelerates the distribution of the electrical field compared to synthetic latex, optimizing toner transfer and thereby enhancing color gamut volume. The study demonstrates that employing the starch NP binder leads to substantial improvements in colorimetric performance without any drawbacks in EP printing, making it highly advantageous to replace 50% of the synthetic binder.