Digitally reconstructing Van Gogh's Field with Irises near Arles. Part 2: Pigment concentration maps

Colors in many paintings of great art historical value have changed over time, due to the combined effects of natural ageing, accumulated surface grime, and materials added during later conservation treatments. The physical restoration of the colors in such paintings is not possible. This article describes one part of work done to digitally restore the colors of Van Gogh's painting Field with Irises near Arles, dating from May 1888. We have used multispectral reflectance data to estimate absorption K and backscattering S parameters of Kubelka‐Munk 2‐constant theory. This was done for all 13 pigments known to have been used by Van Gogh in this painting, and based on this the concentration maps for each of these pigments were calculated. We validated the calculated concentration maps in several ways. For some pigments, we were able to predict spots on the painting where the pigment is expected to occur in unmixed form based on visual examination. For several other pigments, the concentration maps could be shown to agree with XRF data. Finally, for some other pigments the concentration maps were supported by additional evidence from microscopic examinations, remarks in Van Gogh's letters and from early color reproductions. For the 1.7 million pixels for which multispectral data is available, the average color difference between the calculated and measured spectral reflectance curves is CIEDE2000 = 1.05. This further confirms that the Kubelka‐Munk calculations are well suited to describe the variety of spectral reflectance on the painting.     

Simulation of colored illumination in painting using the ostwald system

With modern technology continuing to produce new and clearer pigments, it is becoming more and more important that the painter of today and tomorrow know thoroughly the colors with which he or she works. A color system is invaluable for putting those colors into context. It is not enough to be superficially acquainted with such a system; it is essential that the painter know it thoroughly. Mixing pigments to obtain other colors was adequate and necessary when the painters of the past were dealing with the limited number of pigments available to them. But now it is possible not only to make color an integral part of a painting, but also to use it to duplicate such visual effects as that resulting from the illumination on the scene.     

Chromaticity changes of inorganic pigments in Chinese traditional paintings due to the illumination of frequently‐used light sources in museum

Optical radiation can cause permanent damage to the color of Chinese traditional paintings, which have extremely high responsivity in the museum illumination. In order to obtain quantitative influence laws of artificial illumination on inorganic pigments in Chinese traditional paintings and provide basis for choosing light sources, a long periodic illumination experiment was carried out to examine how prolonged exposure of three light sources (tungsten halogen, metal halide and white light emitting diodes), frequently‐used in museums, affect the chromaticity of five inorganic pigments [azurite (blue), cinnabar (red), orpiment (yellow), ancient graphite (black), clam shell powder (white)], commonly used in Chinese traditional paintings. Through the experiment, we found that the illumination causes a color change to inorganic pigments, and the degree of which is related to the photochemical stability of pigments and the high energy shortwave radiation in the light source spectrum. We also obtain the color change laws of the five pigments and the quantitative relationships of color damage for different painting types. These results can provide data basis for related research on Chinese traditional painting illumination and choice basis for light sources in museum lighting designs.     

Examples of interference and the color pigment mixtures green with red and red with green

In industrial paint formulations, interference pigments are usually mixed with color pigments. Transparent interference pigments mix together according to the laws of additive mixing and color pigments to the laws of subtractive mixing. The behavior of both types differs depending on whether similar colors such as pearl green and green or contrasting colors such as pearl green and red are mixed. In this article examples of these differences for color measurement are discussed, along with showing the resulting charts. © 2001 Wiley Periodicals, Inc. Col Res Appl, 27, 276–281, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10063     

ADDITIVE COLOR MIXTURE WITH FLUORESCENT PIGMENTS AND SPECIAL ILLUMINATION

Although the artist uses subtractive color mixture when the starting point is a white surface and color mixture is accomplished by physically intermixing paints, he can use additive color mixture if he applies his paints to the canvas in small dots, creating a mosaic structure. Conventional pigments, however, lack a high enough relative brightness to synthesize white; the artist must revert to mixing white pigment to his paints to get a full range of lights and darks, just as in subtractive color mixture painting methods. By employing fluorescent pigments with special illumination, the visual artist can now obtain additive primaries of sufficient brightness to synthesize white; thus, for the first time, he can create images in his graphic media using purely additive color mixture.     

浅谈新彩人物画的形神表现

新彩是有别于古、粉彩的新的彩绘形式,具有发色稳定、颜色品种多、附着力强以及彩绘技法多样,艺术表现力强等工艺特色。画好新彩人物,不仅需要扎实的绘画技巧,而且需要全面的艺术修养。     

锆基陶瓷色料的制备及其性能

本文论述了锆基陶瓷色料的制备工艺过程,矿化剂的作用机理以及着色离子在ZrSiO4晶体结构中的价态、取位,为获得性能稳定、呈色效果好的锆基陶瓷色料提供理论指导。     

探究日本色彩中的红色

不同国家和民族对色彩持有不同观念，作为亚洲设计领域的先进国家日本，对红色有着自己独特的理解，历经时日形成了红色的色彩文化。     

Sky blue,but what blue? A new evaluation of the colors of the sky for artists and designers

This study describes a process of relating the perceptual analysis of the colors of the terrestrial atmosphere to currently available pigments used in artists' painting systems. This process sought to discover how the colors of the sky could be defined and simulated by these pigments. The author also describes how confusion over the bewildering choice of suitable pigments on offer in the market place can be clarified. © 2006 Wiley Periodicals, Inc. Col Res Appl, 32, 249–255, 2007     

Hygrothermal aging properties of wood plastic composites made of recycled high density polypropylene as affected by inorganic pigments

The objective of this study is to investigate the hygrothermal aging properties of wood plastic composites (WPCs) made of a recycled high density polyethylene (HDPE) highly filled with wood waste, inorganic filler and pigments with a resin/filler ratio of 27/73. Hygrothermal ageing test of the prepared WPCs with three different colors (original, red, and chocolate) was carried out by immersing specimens in distilled water at 45°C for 70 days. The hygrothermal ageing properties including water absorption, moisture diffusion coefficient, surface color change, and flexural properties of the WPCs were investigated. It was found that pigment colored WPCs have better hygrothermal aging properties including lower water absorption, less total color changes, and higher mechanical property retention rate after 70 days hygrothermal aging test. POLYM. ENG. SCI., 55:2127–2132, 2015. © 2015 Society of Plastics Engineers     

Color management for enhancing the performance of superfine nylon ink jet printing with reactive dyes inks

The challenge for the inkjet printing textiles is that the colors reproduction quality of printed output is an accurate match to the original artwork. Actual evidence from art workers with digital print facilities reveals that they regularly encounter problems in this area. This article concerns the initial stages of an investigation into color accuracy in digitally printed superfine nylon under low temperature plasma pretreatment in order to get a accuracy and color‐increased superfine nylon digital prints. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 346–351, 2017     

Computerized Color Distinguishing System for Color Printed Fabric by Using the Approach of Probabilistic Neural Network

This article proposes an innovative color printed fabric computer color distinguishing system whose main functions are to precisely distinguish the printed fabric pattern colors and match colors to improve the current time-consuming color distinguishing conducted by manpower. The RGB color mode is an industrial color standard, by which the change and overlapping of color channels of red, green, and blue represent types of colors. RGB stands for red, green, and blue, respectively. It is one of the most widely used color system and covers almost all of the colors sensible to human vision. Hence, this paper adopts the RGB color mode to present color printed fabric images. First, to reduce the color distinguishing computation, a genetic algorithm was applied in search of small images of the same color in the original color printed fabric. Then, color distinguishing computation was conducted by a probabilistic neural network (PNN), which has the advantage of a very fast learning speed. Finally, PANTONE® standard color tickets were applied in matching colors. The experimental results revealed that the PNN design can easily realize and achieve accurate, fast color classification. It is proved that this color distinguishing system can be practically applied in printed fabric color distinguishing and matching.     

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.     

Color reproduction on shrink sleeves

Wrapping heat‐deformable plastic labels around packages relies on a shrinking process. Shrinking plastic labels distorts not only the shape but also the color of the printed artwork. In this study, we analyze and model the color shifts induced by shrinkage. The ultimate goal is to generate full color images which after shrinking have colors as close as possible to the original colors. For this purpose, we present a thickness enhanced Clapper–Yule prediction model. Its calibration requires spectral measurements of original, nonshrunk samples, as well as the measured shrinkage factors. With the prediction model, we establish a table creating the correspondences between target colors after shrinking and ink area coverages. This enables creating color images which after shrinking match the original images. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 56–63, 2016     

光子晶体结构色纺织材料的制备及应用研究进展

为解决当前纺织印染行业大量使用高污染、高能耗且易褪色的传统化学染料和颜料的问题,针对结构生色材料所具有的不含着色剂、颜色鲜艳、不易褪色等特点,本文综述了近年来光子晶体结构色纺织材料的制备及应用研究进展。介绍了光子晶体结构及其结构生色机理,阐述了结构色纺织材料常用的制备方法,着重归纳了光子晶体结构色在纤维、纱线、织物及颜料等方面的应用,并分析了其在应用过程中存在的问题。分析表明,光子晶体结构色纺织材料已经可以达到大面积快速制备,且在织物上构筑结构色较为方便且研究较多,在纱线上构筑结构色的研究较少,在纤维上构筑结构色容易赋予其功能性且相关研究逐渐增多。最后总结了光子晶体结构色应用于纺织领域所存在的问题,并对该研究方向进行了展望。     

A general framework to study the price‐color relationship in paintings with an application to Mark Rothko rectangular series

We propose a general framework to study the relationship between the price of a painting and its color‐related attributes. To this end we focus on four key aspects: dominant colors, features of the color palette, color harmony, and color emotions. We demonstrate the usefulness of this approach with an example based on Mark Rothko's post‐1950 paintings (the “rectangular” series), and auction data from the 1994 to 2018 period. We identify two distinct price‐color regimes in Rothko's market: (a) [1994‐2005], a period in which prices are explained mainly by the growing popularity of the artist regardless of the color attributes of the paintings sold; and (b) [2006‐2018], a period in which color‐related attributes explain most of the prices. Furthermore, we find that in this second period, the dominant colors and the diversity of the color palette, are by far the most relevant attributes that influence the price; color harmony and color emotions hold almost no explanatory power during this period. Finally, we propose a new metric based on the Herfindahl Index to describe color diversity; this metric seems to be promising at characterizing the effect of the color palette on the price of a painting.     

Shedding light on the colours of medieval alabaster sculptures: Scientific analysis and digital reconstruction of their original polychromy

Although medieval alabaster sculptures might appear white at present, they were colourful once, because painting and gilding the stone was an integral part of their production. This work presents the study of polychrome remnants on a selection of fourteenth century English alabasters, using multiple scientific methods (microscopy, spectroscopic and chromatographic techniques). The range of pigments identified include vermilion, red ochre, red lead, kermes, verdigris, copper resinate, azurite, lead white and carbon black. Some sophisticated decorative techniques were also observed, namely the application of translucent glazes on top of raised gilded motifs. The analysis was useful in understanding the degradation processes undergone by some materials, such as verdigris. The use of oil as binding medium for the application of the paint layers and a mordant gilding technique were determined. These findings yielded important clues towards the digital reconstruction of the original appearance of the polychrome surface, which is also presented here.     

Digital color reconstructions of cultural heritage using color‐managed imaging and small‐aperture spectrophotometry

There are many examples of cultural heritage having optical properties that have changed with the passage of time. Examples include the yellowing, darkening, and fading of paints and varnishes caused by light exposure and atmospheric pollution. When it is infeasible to treat an object, an image simulation can provide a view to the past, known as a color reconstruction. A technique is described that relies on a color‐managed image, spectral reflectance factor measurements of the object, an optical model of colorant mixing, an optical database of artist materials, spreadsheet software, and image editing software. Spectral calculations are used to create adjustment curves where segmented portions of an object's image are translated in color. This approach has been used to produce color reconstructions of paintings by Vincent van Gogh and Georges Seurat. This colorimetric translation methodology is described and an example shown for the Chicago version of Vincent van Gogh's Bedroom. The methodology is compared with pixel‐based processing.