修正マンセル表色系における彩度差と知覚される色差との比較

Abstract

The perceptual uniformity of chroma-spacing in the Munsell renotation system was examined by comparing Munsell chroma-differences with perceived colour-differences on the basis of the data obtained by visual experiments in which ratio method had been used to estimate perceptual colour-differences for color chips with constant value (V=6) and hues (5R, 5YR, 5Y, 7.5GY, 3.5G, 10BG, 2.5PB, and 5RP) and varying only chroma. It was cleared that the Munsell chroma did not completely retain perceptual uniformity.Results obtained are summarized as follows:(1) For any hue except 5R, 5Y, and 2.5PB in the hues treated, the perceived colour-differences tend to become relatively small with increasing saturation. This tendency is remarkable in the hues of 5YR, 7.5GY, and 10BG.(2) The above means that the chroma spacings in the Munsell renotation system become narrow with increasing saturation as compared with perceptual chroma spacings. In the instance of 7.5GY, the perceived colour-difference per unit Munsell-chroma at 9-10C is 0.45 times as large as that at 0-1C.(3) The Munsel chroma for 5R may roughly retain the perceptual uniformity in the range of lower chroma than 10C, and the same thing may be stated in respect of the hue 5Y within lower chroma than 7C and the hue 2.5PB within lower chroma than 9C. But, at the remainders of chroma for 5R and 5Y, the perceptual chroma-spacings become relatively small with increasing chroma.(4) The experimental values of perceived colour-difference per unit colorimetric one can be approximated by the function that consists of a term of one-third power, a linear term, and a constant term within the mean square errors less than 5.31×10-2 for all the hues.