Scaling of saturation and hue in the nonspectral region

Abstract

The saturation of two nonspectral hues, magenta and violet, and the hue shift between red and blue through the nonspectral region were both scaled by two methods, equisection to produce a difference scale, ψ D, and ratio judgments to produce a magnitude scale, ψ M. The colored stimuli were viewed through apertures in a dark surround, with the luminance kept constant at one of three levels, 0.5, 2.5, and 12.6 cd/m 2. As previously found with saturation and hue shift between two adjacent primary hues in the spectral region, WD was linear with colorimetric purity for the saturation of magenta or violet and with the mixture ratio of red or blue for the hue shift, whereas ψ M was a power function of colorimetric purity for the saturations and of the mixture ratio for the hue shift with exponents larger than unity in both cases. The present results were combined with previous results to give the change of parameters for saturation functions over the entire hue circle. © 1978 Psychonomic Society, Inc.