MEASUREMENT OF COLOR CONSTANCY BY COLOR MEMORY MATCHING

Degree of color constancy was measured when color memory was involved in color comparison judgment. We used the Optical Society of America ( OSA) Uniform Color Scales as stimulus color samples, and chose 20 colo r samples as test stimuli. Four illuminants of 1700, 3000, 6500, and 3 0,000 K were tested. The observer, completely adapted to a test illumi nant, saw a test color sample and stored its color in his memory. Afte r being readapted to the reference white (6500 K), he started selectin g a color sample from among the 424 OSA samples which matched the test sample in his memory. We employed a memory matching method called cas cade color matching, in which the number of selected color-samples was gradually reduced in four stages. In the final stage, the observer se lected a color sample. The results show that, for most test colors, th e distributions of selected colors in stages 1 to 4 were similar among all illuminants, and that the u'v' chromaticity distance between a te st color under 6500K and its matched color was quite short. These indi cate that good color constancy was retained in memory color comparison .