Unique Hue Judgments Under Light Sources With Different Chromaticities

Abstract

A psychophysical experiment was carried out to investigate how light source chromaticities affected unique hue judgements using Munsell samples at two chroma levels. Ten observers between 20 and 23 years of age (mean = 21, std. dev. =1) participated in the experiment. Each observer was asked to select the unique hues from the 40 V6C8 (Value 6 Chroma 8) Munsell samples and 40 V8C4 (Value 8 Chroma 4) Munsell samples under six light sources. The experiment results showed that the hue angles defined in CIECAM02 were similar to the unique red and green judgments made by the observers, but not to the unique blue and yellow judgements. For unique blue, the observers' judgements generally shifted toward green. The observers' judgements on unique yellow varied with the chroma levels of the samples and Duv levels of the light sources.