DIURNAL-VARIATION OF HUE DISCRIMINATORY CAPABILITY UNDER ARTIFICIAL CONSTANT ILLUMINATION

Diurnal variation of hue discriminatory capability under artificial co nstant illumination of 4000 lux was studied with 10 young female adult s using the 100-hue test. There were conspicuous diurnal variations in the yellow-blue and red-green systems, with marked reductions of erro r score in the evening. However, observations of the blue, yellow, gre en and red systems separately disclosed that there existed clear diurn al rhythms in the blue and green systems, but not in the yellow and re d systems. This suggests the existence of diurnal variation in functio n of the S and M cones responsible for the blue and green hue.