Principal hue curves and color difference

✍ Scribed by Tarow Indow

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 640 KB
• Volume: 24
• Category: Article
• ISSN: 0361-2317
• DOI: 10.1002/(sici)1520-6378(199908)24:4<266::aid-col7>3.0.co;2-n

✦ Synopsis

The size of perceptual difference of colors (j, k) is scaled as d jk by selecting a pair of Munsell grays in which the lightness difference matches in size with the color difference. Hence, d is given in terms of Munsell V. The degree of principal hue component ␣ in a color j is scaled as ␣ (j) by making marks on a line segment and the range of ␣ is from 0 to 10. By plotting ␣ (H V/C) on Munsell H-circle, principal hue curves ␣ (H V/C) are defined, where ␣ ϭ R, Y, G, B, V ϭ 4 -7, and C ϭ 2-10. In this process, similar plots of NCS codes (c ␣ ) are used as references. The curves ␣ (H V/C) tell us the appearance of Munsell colors (H V/C) and also enable us to predict color differences. The relationship between d jk and ⌬V ϭ

is tested in various ways, e.g., logarithmic, power, Minkowski-type functions. The best predictor d ˜is given by a simple linear form, d ˜ϭ a V ⌬V ϩ {d 0 ϩ ⌺a ␣ ⌬ ␣ }. For 899 pairs (j, k), 706 differing in H, C and 193 differing in H, V, C, a V ϭ 0.459, d 0 ϭ 0.610, a R ϭ 0.199, a Y ϭ 0.031, a G ϭ 0.098, a B ϭ 0.136, and the root-mean-squares of (d jk Ϫ d ˜jk ) is 0.338 in the matched V-unit.