ICI Specifications of Difference Limens for Munsell Hue, Value, and Chroma

Abstract

In an earlier two-year study, color difference limens of three observers were determined separately for each of the Munsell analogs of hue, saturation, and lightness at each of a number of locations in the surface-color solid. The present paper makes these data available in terms of the standard I.C.I. system and so helps to make that system more visually meaningful. In addition to detailed tabulations of the x, y, and Y specifications, the means of the chromatic difference limens of the three observers are plotted in the I.C.I. chromaticity coordinates at three levels of reflectance. Absolute chroma limens for Munsell red, yellow, green, blue, and purple are tabulated at seven levels of reflectance. The general order of magnitude of all the liminal determinations may be indicated by the fact that the trichromatic coefficients and reflectance figures representing them are confined to the third and fourth decimal places. In terms of distances in the chromaticity diagram, the general mean hue and chroma limens were, respectively, 0.0023 and 0.0035; and the mean Fechner fraction from the value data turned out to be 0.0087.