Equiluminance: spatial and temporal factors and the contribution of blue-sensitive cones.
Equiluminance ratios for red/green, red/blue and green/blue sine-wave gratings were determined by using a minimum-motion heterochromatic matching technique that permitted reliable settings at temporal frequencies as low as 0.5 Hz. The red/green equiluminance ratio was influenced by temporal but not spatial frequency, the green/blue ratio was influenced by spatial but not temporal frequency, and the red/blue ratio was influenced by both. After bleaching of the blue-sensitive cones, there was no change in equiluminance ratios, indicating no contribution of the blue-sensitive cones to the luminance channel even at low temporal and spatial frequencies. The inhomogeneity of yellow pigmentation within the macular region was identified as the source of the spatial-frequency effect on the blue/green ratio.
D003116:Color; D003118:Color Perception; D006801:Humans; D008027:Light; D008297:Male; D010786:Photoreceptor Cells / Q000502:physiology*; D013028:Space Perception; D013997:Time Factors