Global Color Metrics and Color‐Appearance Systems

The Munsell Color System, the color‐appearance system most widely used, has been constructed primarily on the basis of local perceptual uniformity. However, when it is used as a criteron for a uniform chromaticity scale, its global structure is important as well, and this structure is examined in three ways. First, the coordinates H, V, C are shown to function as a conceptual framework in identifying colors. Second, a summary of 12 studies by multidimensional scaling methods based on large color differences is given. It shows that the main part of the Munsell space is approximately Euclidean. Third, a new method based on estimation of principal hue components in each color, 120 in an experiment, yields the same result. Chromatic response functions as in opponent‐color theories are obtained with object colors by this method. In all the results with Japanese observers, 5PB and 5B appear to be too close and both deviate toward 5G compared with the Munsell notation. Whether the finding is due to the observers is discussed.