木塑活动房外墙挂板自然老化性能的研究

针对木塑活动房各外向墙体接受太阳辐射强弱的不同,利用KONICA MINOLTA CR-10小型色差计测定了各方位墙体挂板(分表面打磨、未打磨材料)8个月户外自然老化过程中明度值L*、色度值a*、b*及色差△E*,分析了不同方位墙体挂板颜色变化及表面打磨、未打磨挂板色差程度的差异.结果表明:8个月自然气候暴露期间,木塑活动房各方位墙体挂板的L*、△E*呈上升趋势,α*呈波动趋势有升有降,b*呈下降趋势.东墙表面打磨木塑挂板色差变化大,南墙表面未打磨木塑挂板色差变化大,北墙表面打磨与未打磨挂板色差变化都是最小的;经过8个月自然老化实验,该木塑活动房发生了褪色,表面未打磨木塑挂板的色差变化大于表面打磨木塑挂板.且各墙体色差变化超过了可识别程度,受太阳直射的墙体挂板褪色偏向于明显.     

CIE 1976(L*a*b*)色空间在PVC-U型材颜色测量中的应用

通过对GB 11186-1989《涂膜颜色的测量方法》标准中关于CIE 1964补充标准色度系统、CIE 1976(L*a*b*)色空间的色坐标及色差公式和光与颜色的相关理论的分析,解析了GB/T 8814-2004《门、窗用未增塑聚氯乙烯(PVC-U)型材》中有关型材颜色测量要求,并给出了灰卡级数与总色差的换算关系。     

基于图片的传统青瓷分类色度学研究

使用拍摄及出版条件尽可能相同的图片代替实物标本对青瓷进行了色度信息采集,利用可见光分光反射光谱主波长及在CIE1976 L*a*b*颜色空间中的色度值L*、a*、b*、C*、h°等进行对比研究,得到了区分青瓷釉色的客观测量依据。结果表明:基于图片的传统青瓷分类方法是可行的,从而解决了实物分散测量难度大且难以寻找平面测量的难题。测试数据表明12种青瓷的色调角算数平均值■有明显的差异,不同名称的传统青瓷有不同的h°值范围,因此色调角h°可作为区分青瓷釉色的主要特征参数。对比传统青瓷釉式,随着Fe_2_O__3含量的增加,12种青瓷釉色越深,其名称排列与其■由小到大排列基本吻合,这进一步验证了用色调角h°区分青瓷的可行性。而色度值L*、C*变化不大无法直接区分釉色;△a*、△b*值在区分同一坐标轴上的色差时较为清晰,但两者同时使用时,区分多种颜色没有明显规律;样品的反射光谱曲线主波长范围重叠率过高,较难区分青瓷类别。     

CIE1976 L*a*b*均匀色空间下照度对锰铝榴石颜色的评价

通过照度实验,基于CIE1976L*a*b*均匀色空间研究照度对锰铝榴石颜色评价的影响.照度增加,锰铝榴石黄色的明度L*显著增加,且自身明度较低的锰铝榴石黄色明度更易受照度变化的影响.△a*平均为17.30,△b*平均为36.83,明显大于△a*的均值,表明照度对锰铝榴石黄色调的影响更大;当照度较低时,彩度C*与照度呈正相关,当照度超过227.73 lx后,C*将不再增大或与照度呈负相关;色调角h0随照度增加而增大,平均色调角增量△h0=11.59,增幅较明度和彩度小.同时验证Stevens效应、Hunt效应、Helmholtz-Kohlrausch效应、Bezold-Brücke色相偏移理论在锰铝榴石颜色观察上的体现.此外,当明度差值DL* ＞15时,DL*与色差DE2000呈正相关且相关性最大,说明明度对色差具有最大贡献.得出结论,照度影响锰铝榴石的明度、彩度、色相,间接影响色差,其中对明度影响最直观,故在质量评价时应严格控制照度标准.     

PVDF氟碳涂料色差影响因素探究

考察了烘烤温度(PMT)、烘烤时间与涂层厚度对PVDF氟碳涂料表面色差的影响。结果表明:PMT、烘烤时间与涂层厚度对PVDF氟碳涂料表面色差均有影响,其中PMT与烘烤时间的影响较涂层厚度的影响小;随着PMT升高、烘烤时间延长和面漆涂层厚度的增加,涂层色差呈增大趋势;色差中ΔL*值的影响较Δa*和Δb*值大。     

基于CIE 1976 L* a* b*色空间的翡翠绿色明度的质量评价

通过翡翠绿色明度与彩度、明度与色差等关系的研究,确定明度对颜色质量评价的作用.三维均匀色空CIE 1976 L* a* b*中,当翡翠绿色的明度较低即L*<19.52时,明度与彩度呈正相关;当19.5260时,明度则与彩度呈负相关.通过CIE DELAB、DECMC、CIE DE2000三个色差公式的计算,证明DL*是决定DE的直接因素, DC*次之,而DH*对色差几乎无贡献.得出结论,翡翠绿色的质量评价应以明度为首要因素,这是最直观且最符合色知觉效果的,而后依次为彩度与色调角两个标准.     

颗粒大小及分布对蓝色陶瓷墨水呈色和稳定性能的影响

本研究以有机溶剂为分散介质,添加适当的分散剂,通过纳米制备系统分散制备蓝色陶瓷墨水。采用MASTERSIZR-2000型激光粒度分析仪、CM-2600D色差仪等手段分析研究了研磨分散时间与墨水颗粒之间的关系,墨水颗粒度对墨水的呈色和悬浮稳定性的影响。研究表明,随着研磨时间的增加,墨水颜料颗粒粒径减小,分布变窄;随着平均粒径的减小,明度值L*、a*减小、b*增大;墨水粒度愈小,分布愈窄,墨水的稳定性愈好。     

基于CIE LAB色差公式的翡翠绿色明度差对色差的贡献

通过翡翠绿色的色差计算,分析明度差DL、彩度差DC、色调差DH对综合色差DE的贡献.采用CIE L*a*b*均匀色空间中CIE LAB色差公式的计算结果显示,肉眼下66粒质地细腻、绿色均匀的优质翡翠戒面的明度值L*∈(38.50,61.80),属中等偏低的明亮程度;彩度范围C*∈(11.49,44.99),也属中等偏低;色调范围h0∈(134.32,152.96),属略带黄色调的鲜艳绿色.翡翠绿色的平均色差DELAB-AVE=6.10达肉眼可识别级别,平均饱和度差-0.22与平均色调角差0.06均很低,对总色差贡献不大,而明度差DL则表现出了与总色差很高的一致性.得出结论,对中低明度的翡翠绿色色差的最直接贡献者为其明度差,依此建议采用首先以彩度和色调的二元体系作为翡翠绿色定量分级体系,进而依据三维均匀色空间模型CIE L*a*b*,构建以色差为基本单位,明度为Z轴、彩度为X轴和色调为Y轴的三元质量分级体系.     

基于数字化色彩的褐煤蜡颜色品质模型初探

采用CIE Lab颜色空间技术,对褐煤蜡的颜色品质进行数字化表征,在检验识别工具准确性的基础上,确定了颜色参数的权重排序及其相关影响,并初步建立了一个用于评价褐煤蜡品质优劣的拟合函数模型y=0.9*L-│0.02*a│-│0.08*b│,其结果值高低所代表的品质优劣程度与人的视觉感知趋势完全相符。     

硅酸锆基三元色料的混色问题研究

陶瓷色料混色能够在一定程度上解决高温陶瓷色料的色彩匮乏问题,但混色问题缺乏系统的研究。本文选择包裹红、锆镨黄、钒锆蓝三种硅酸锆基色料进行混色问题研究。结果表明:色料的混色能够丰富高温颜色的种类。混色机理是三种色料反射不同波长的可见光后产生的协同作用,且对混色的影响是相互独立的。包裹红色料会使混色的L*值减小,a*值增大;锆镨黄色料会使混色的L*值和b*值减小,a*值增大;钒锆蓝色料会使混色的a*值和b*值减小。     

A new color image space HRU related to the CIEL*a*b* color space

The color image space with one kind of merit color image scales (WIP) is derived using the psychophysical method of magnitude estimation method, usually used in visual assessment of color appearance, which can be used to describe the color image meanings of colors of works of art in parallel with those of people. The results show that a new color image space HRU is developed, and the relativity between this space and the CIEL*a*b* color space is also discussed. And, a good relationship between the HRU color image space and the CIEL*a*b* color space can be found. This may be of great advantage to the new color image space HRU in predicting the color image for single color based on the color space CIEL*a*b*. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 452–457, 2009     

不同纸张对数字输出阶调特性的影响

为了了解不同纸张对数字输出阶调特性的影响,采用CorelDraw软件制作单色色阶测试版,选择常用的普通打印纸、一般照片纸和光泽照片纸在Epson Stylus Photo R250彩色喷墨打印机上进行输出,用DS分光光度仪对输出色阶进行CIEL*a*b*色度值的测量,用色彩管理软件为不同纸张制作特性文件,对不同纸张所能达到的数字输出阶调特性进行定量分析。针对选用的纸张进行测量后得出结论,输出色彩丰富的图像优选的纸张应是光泽照片纸,输出灰度层次丰富的图像可以选择普通打印纸。     

Color effect of light sources on peridot based on CIE1976 L*a*b* color system and round RGB diagram system

Previous research indicated that the peridot's color is dominated by the selective absorption of visible light caused by ferrous ion, the hue angle of which is in an inverse ratio of the concentration of Fe²⁺. This article focuses on the color effect of peridot under different standard light sources based on the CIE1976 L*a*b* color space system and round RGB diagram system and tries to find the best one for its grading and display. Based on the results of a series of experiments, including electron microprobe analysis, spectrophotometer, UV‐Vis spectrum, standard illumination box, and Munsell neutral color chips, it was suggested that the spectral power distribution and color temperature of a standard light source significantly influence the color of peridot in terms of lightness and chroma, particularly in the hue of peridot. As for color grading and displaying of peridot, standard light source A fails to fit in, and the color of peridot under a fluorescent light source has a higher chroma but a lower hue angle than that under daylight light source. The best choice for grading and displaying peridot is the standard light source D₆₅. It is better to distinguish the hue of peridot when it is calculated by the round RGB diagram system.     

Color assessment of granitic rocks and implications for their ornamental utilization

The purpose of this study is to evaluate the factors affecting the assessment of granite color, such as grain size and texture, and to propose a methodology for this task which would reduce the margin of error associated with this procedure. For this purpose, an evaluation was carried out on the color of several granites with different textures used in the dimensional stone industry to highlight the importance of the sample area, the number of measurements per sample and the aperture of the equipment. A colorimeter was used to measure the granite color according to the CIE‐L*a*b* and CIE‐L*C*_abh_ab systems, in both large slabs and small samples selected in a processing plant of ornamental granites. Granite color characteristics from large slabs had to be obtained with at least 60 shots due to the variation between different slabs. Therefore, several samples are needed for granite characterization. The color of gray granites does not vary significantly. Nevertheless, the more weathered granites show significant differences which are more evident in the b*‐parameter, or the yellow–blue component, which allow the use of the colorimeter for quality control. By doing so significant differences among the rock pieces used in a single building can be avoided. There were no significant differences found in the color parameters from distinct apertures. However, due to the heterogeneity of the granite the color is evaluated better with larger apertures. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2012     

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     

Color memory in elderly adults

The methods of simultaneous and successive color matching have been compared for a set of five Munsell color samples by 50 older adult observers, 25 men and 25 women (ranging in age from 64 to 80 years). From comparison between this population and one of 50 younger adult observers, 25 men and 25 women (in the 20–27 age range), we can deduce, in general, the following: (a) In the elderly adults the mean CIELAB total color difference (ΔE*_ab) in simultaneous color matching is lower than the ΔE*_ab by memory color matching. (b) While younger adults matched well the color of all the reference tests, the elderly adults matched poorly both greens and orange. (c) Younger adults remember the original color better than do the older adults (P = 0.007), depending on gender and delay time. (d) Although with simultaneous matching, the observer's gender does not determine significant differences, by memory, men matched the color of reference test more poorly than did women (P = 0.0), independently of age, color and delay time, especially for bluish green, violet, and pink. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 458–467, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20258     

An optimisation study of colour measurements on digitised slides of painted works of art

This paper deals with the problem of the colorimetric fidelity of digitised colour slides of painted works of art. A six-matrix conversion model was derived that permitted the transformation of any RGB device-dependent measurement on digitised colour slides to XYZ CIE 1931 device-independent values. The model was calibrated against a reference colour chart. Eighty-one uniformly-painted colour samples were photographed together with a painting on a 4 × 5 inch colour slide that was digitised using a high resolution scanner. A 3 × 3 transformation matrix, of the corrected R, G and B values and the respective X, Y and Z tristimulus values provided by spectrophotometry, was calculated. The calculated matrix was then applied to a 13th century Byzantine fresco, captured on the same digitised slide, to transform the RGB measurements to XYZ CIE 1931 device-independent values which were then converted into the L* a* b* CIE 1976 colorimetric system.     

Applying image‐based color palette for achieving high image quality of displays

In the highly competitive display market, manufacturers continuously develop new technologies to improve the image quality of displays. However, color measurement and visual assessment are time‐consuming to production lines. A new method to measure and improve color quality of the displays automatically therefore, is urgently needed to the manufacturers. This article proposes a familiar color correction strategy to optimize the colors of different displays by means of creating an image‐based color palette which enables color correction for familiar objects (e.g., facial skin, blue sky, or green grass) in the multidisplay systems. To produce the image‐based color palette, the 8‐bit RGB value of each pixel in an image is transformed to L*d*n* (lightness/dominant color/nondominant color) color channels, and the dominant‐color regions in an image are subsequently extracted from the dominant color (d*) channel. The memory color data of familiar objects can be set in reference monitor in advance to determine the dominant color (d*) channel. Then a series of palette colors are generated around a displayed image. The color palette will be displayed as a target for two‐dimensional colorimeter shooting to obtain the measured color data. The familiar color correction model was established based on a first‐order polynomial regression to achieve a polynomial fit between the measured color data and the reference color data on the color palette. The proposed method provides a solution to correct familiar colors on a displayed image, and maintains the original color gamut and tone characteristic in the multidisplay systems simultaneously. It is possible to achieve the preferred intent of the displayed images by using the proposed familiar color correction method. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 154–168, 2014     

Color separation for colored fiber blends based on the fuzzy C‐means cluster

Colored fibers can be blended in a certain proportion to achieve a specific color. It is a very hard task for the colorist to find a good recipe to meet the final product without the aid of computer. In this article, a color separation method for the colored fiber blends is discussed to substitute for some manual work. The fuzzy C‐means cluster is a way to group the color in the colored fiber blends image. The distance index, which is a key factor during the fuzzy C‐means cluster process, is calculated in the RGB color space and the HSV color space with some transformation. The final experiment result proved that the colors of each pixel in the blends' image can be replaced by corresponding cluster center associating colors in the HSV color space, and the main texture as well as the main color information about the fibers in the image is preserved. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2012     

Color coordinates of objects with daylight changes

Colorimetric changes were analyzed for a broad set of natural and artificial objects that were illuminated by daylight measured at different solar elevations on separate days, under diverse meteorologic conditions. The changes in L*‐, a*‐, and b*‐color coordinates of the objects, when illuminated with daylight at the maximum solar elevation and at twilight, normally exceeded 3 CIELAB units. However, color differences were not significant when evaluated during the middle hours of the day. Nor were significant differences found in the color of an object on different days, when evaluated during the middle hours. Color appearance attributes of the objects at intervals during the day were also calculated based on the CIECAM97s color appearance model, showing the trends with daylight changes. © 2002 Wiley Periodicals, Inc. Col Res Appl, 28, 25–35, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.