Color Research and Application最新文献

Between 1924 and 1947, Gino Severini decorated five churches in the Romand region of Switzerland with monumental religious wall paintings. This mural art played an important role in the Italian artist's career despite being mostly unknown and not easily found. The painting methods and materials of these modern Swiss murals were characterized by combining historical and archival research with onsite visual and scientific examination. Most pigments were identified with noninvasive methods integrating mapping techniques (i.e., technical photography and digital microscopy) with point analysis (x-ray fluorescence and reflection FT-IR spectroscopy). The results of these portable techniques were completed with SEM-EDS, μFT-IR FPA imaging, and μRaman analyses on micro-samples which provided stratigraphic and compositional information to complement the noninvasive results. Overall, the data obtained show that Severini used both traditional pigments (e.g., Sangiovanni white and ochres/earths of various color) and modern ones, such as cadmium-based pigments, with different painting techniques (e.g., zinc white was applied exclusively a secco). Apart from cerulean blue (cobalt stannate) and Naples yellow (lead antimonate) found only in two locations, the same set of pigments was documented in all of Severini's Swiss murals. The characterization of the artist's palette is important to understand the technical painting process followed by Severini, his interest on new painting materials available on the market and, at the same time, loyalty towards traditional painting methods, such as painting a fresco.

The Universitat de València brings together artistic collections of great value that embrace more than five centuries of history (1499–2022). Among them, the collection of contemporary painting stands out for its diversity of artists, artistic techniques and themes. One of the aims of the Vice-rectorate for Culture and Society of the Universitat de València is the study, conservation and dissemination of its art collection, implementing innovative methodologies that will place these artworks at the research and transfer frontline. To achieve this, the Laboratory for Analysis and Diagnosis of Works of Art of the Universitat de València: Conservation, Legacy, InnOvation has recently optimized a multi-analytical artistic diagnosis approach that combines the use of multiband technical photography (MTP) with digital radiography, infrared reflectography (IRR) and hyperspectral camera. The noninvasive methodology developed for the studied paintings, belonging to different historical periods, is completed by using a portable X-ray fluorescence. The final goal is to obtain useful information on the composition and execution technique, issues of great interest for developing preventive conservation plans for the collections and for the design of innovative exhibition proposals of an immersive and accessible nature. This article presents the results obtained for three paintings that were made by one of the most unknown Valencian painters of the early 20th century, despite the great quality of his work: Manuel Moreno Gimeno (1900–1982). These paintings are part of the aforementioned art collection of the Universitat de València, and are housed at the Faculty of Medicine. In this study, the use of MTP, IRR and hyperspectral imaging techniques were combined with the analysis of the pictorial surface using a portable optical microscope and a portable X-ray fluorescence. The results obtained indicate that Manuel Moreno Gimeno developed a landscape painting technique that was very close to that of other Valencian painters of the early 20th century. The handling of light and color was achieved using a rich color palette that included numerous contemporary innovative pigment such as chrome or cadmium.

The spectral reflectance is recognized as the fingerprint of an object surface and has been used to achieve accurate color measurement in textile and other fields. Spectral reflectance can be recovered from color images to preserve high spectral and spatial resolutions simultaneously. However, a color camera commonly supplies a non-raw color image, which is non-linear with respect to the scene radiance, and is inappropriate for quantitative analysis. In this study, for non-raw color images, different nonlinearity correction models are designed and evaluated with respect to different spectral estimation algorithms. The colorimetric and spectral accuracy of spectral estimation after the nonlinearity correction is assessed through both simulation and practical experiments. In the simulation, a large number of spectral images from several datasets are employed to directly verify the effectiveness of the nonlinearity correction. In the practical experiments, the spectral estimation accuracy following the nonlinearity correction is verified directly and indirectly based on actual color images. The resulting linear color image data after the nonlinearity correction can provide better spectral estimation accuracy especially for the PI algorithm with one power-function based model. Besides, the combination of the simple PI algorithm with the power-function based model can exceed other combinations comprising complex algorithms and models in both accuracy and efficiency. For the linear color image data, the PI algorithm even surpasses the deep learning-based methods in certain metric, thus indicating a shallow relationship exists between the linear color image data and the spectral reflectance.

In 1952, contemporary artist Federico Silva (Mexico City, 1923–2022) carried out the first outdoor mural painting: The technique at the service of peace. At the end of 2021, the project for the study and conservation of this mural began with a diagnosis of its conservation, which was done through a multi-technique study based on the experience acquired in research projects from other contemporary mural paintings. This included the proposal of an adequate conservation strategy to resolve the stability of the painting, since the behavior of the synthetic paints exposed to the different effects of the outdoor environment has altered the perception, form and meaning of the mural. Main results from this approach by documentation and global examination with Visible Imaging and Digital Microscopy, allowed us to describe the color palette and its alterations. Additional examination of cross sections acquired from this mural, allowed a material characterization by means of optical microscopy (OM), micro-hyperspectral imaging, Fourier transformed infrared spectroscopy and X-ray fluorescence spectroscopies.

The present study investigated whether the clothing color of female stimuli and the perceived attractiveness judgments of Caucasian and Chinese male observers for own- and other-ethnicity are correlated. Results indicate that Caucasian observers evaluated stimuli in white and black as the most attractive while giving low ratings for stimuli in orange, yellow, or lime. Results for the Chinese observers were found to depend on the stimulus type, whereby the Caucasian stimulus received significantly lower ratings when dressed in lime, and the Chinese stimulus was rated as the least attractive when in lime, orange, green, or cyan. White was found to have a positive effect on Chinese observers' ratings for both stimuli. A comparison of the general versus the facial attractiveness lends some evidence that red enhanced Caucasian observers' attraction to the Chinese stimulus while findings fail to support the general red-effect. We propose a potential mechanism underlying the color-attraction associations.

With the rapid development of mobile imaging devices, there is a strong desire for accurate image reconstruction. However, the conventional colorimetry system is often related to environmental illuminations. Spectral reflectance is the fingerprint of color and is invariant with environmental illuminations. Therefore, the goal of the present study is to verify different algorithms to reconstruct the spectral reflectance from the camera red, green, and blue responses. In this research, the weighted local sample selection method was first combined with pseudo inverse matrix method (PI) and Wiener estimation method (WE) to investigate the optimal sample number on the model accuracy. The optimum local sample numbers of the two combination methods were established. The performance of five methods was evaluated, including PI, WE, smoothing constraint method, weighted pseudo inverse matrix method (WPI) and weighted Wiener estimation method (WWE) under lightings varying a wide range of correlated color temperature (CCT) from 3000 to 10 000 K. The best algorithm (WPI) in different lighting environments was established. The metamerism of different materials was revealed, the impact of materials on training and testing samples was reported. Finally, the methods' performance under different CCTs was revealed in terms of root mean square error and CIEDE2000, and the results from the theoretical simulation and real camera capturing were compared.

In the restoration of historic facades, specialists need to tackle the problem of colors applied to the ornamental elements that appear different on a facade than if they were isolated, because the colors of the surrounding surfaces influence them through color induction. This study evaluates the difference between the colors of ornaments observed in isolation, which we call nominal colors, and on different background colors, which we call induced colors, considering the historic color palette of Valencia as studied by the Color Research Group in Architecture of the Universitat Politècnica de València. The study consisted of the evaluation of 108 color pairs painted on physical cardboards, rated by 26 female students (average age 26.5), under natural lighting conditions, and using the Natural Color System (NCS) Color Atlas for the color match. Results indicate that induced colors have lower NCS blackness compared with nominal ones, and slightly higher or no NCS chromaticness shift. Nominal colors with low chromaticness exhibit an important hue induction effect and tend to shift to a hue that is located opposite to that of the background color in the NCS color circle, this effect being larger when the background has a warm color. The induction effect is larger when ornamental elements and background have similar nominal NCS blackness, and different nominal NCS chromaticness,with nominal hue difference no significant in the induction effect. The colors of ornamental elements that entailed greater induction were those with the lowest NCS chromaticness, and in the case of the background color, those with the highest chromaticness.

Much research has been done on the relationship between emotions and colors, and many color scheme recommendation tools have been developed. These tools can often help recommend a suitable color scheme to express a certain emotion, but it is still difficult to design satisfying schemes based on such recommendations. In this study, based on the Color Scheme Bible, Compact Edition, we developed Emocolor, which allows professionals to generate a large number of color schemes based on emotional words or emotional images. It is also used to iteratively optimize the generated color schemes based on an interactive genetic algorithm to find the color scheme design that best matches the user's emotion. Through the evaluation of tram color schemes based on emotional words, Emocolor can effectively generate tram color schemes that match users’ emotions. It can also effectively transfer the emotion of an image with a single dominant color to a tram color scheme. In short, Emocolor can help professionals describe the relationship between emotion and color in a more accurate way and design emotional color schemes. Emocolor can be applied in advertising design, product design, interior design, and other fields.

Accurate characterization of color depth is important for assessing a dye's relative strength, color fastness, and so on. There are several formulas for color depth, however, with evaluation effects that are quite different. In this study, we attempt to investigate the equi-depth properties of the color depth formulas so as to provide a reference for selection. One thousand two hundred and six color samples were dyed around six standard depths of three hues in SDC Standard Depth Scales. Sixteen observers were recruited for “Pass–Fail” psychophysical experiments. More than 30 000 experimental data points were obtained to calculate the values of discrimination thresholds and acceptable tolerances at six different standard depths for each formula. The equi-depth properties of five main color depth formulas were statistically analyzed through their coefficients of variation (CV)% values. Results show that the Yang3 formula is optimal for both color depth discrimination threshold and acceptable tolerance, and its average wrong decision is less than the minimum wrong decision of all observers, as well as those of the other four formulas. Overall, Yang3 formula shows the best equi-depth and highest relatively accuracy among the five formulas.