| Abstract: | The size of perceptual difference of colors (j, k) is scaled as djk 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 α in a color j is scaled as ξα(j) by making marks on a line segment and the range of ξα is from 0 to 10. By plotting ξα(H V/C) on Munsell H‐circle, principal hue curves ξ¯α(H V/C) are defined, where α = R, Y, G, B, V = 4–7, and C = 2–10. In this process, similar plots of NCS codes (cϕα) are used as references. The curves ξ¯α(H V/C) tell us the appearance of Munsell colors (H V/C) and also enable us to predict color differences. The relationship between djk and ΔV = |Vj − Vk|, Δξ¯α = |ξ¯α(Hj Vj/Cj) − ξ¯α(Hk Vk/Ck)| is tested in various ways, e.g., logarithmic, power, Minkowski‐type functions. The best predictor d̃ is given by a simple linear form, d̃ = aVΔV + {d0 + ΣaαΔξ¯α}. For 899 pairs (j, k), 706 differing in H, C and 193 differing in H, V, C, aV = 0.459, d0 = 0.610, aR = 0.199, aY = 0.031, aG = 0.098, aB = 0.136, and the root‐mean‐squares of (djk − d̃jk) is 0.338 in the matched V‐unit. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 266–279, 1999 |
