Color differences scaled by chromatic modulation sensitivity functions

Abstract

Chromatically-modulated spatial stimuli were produced by superimposing two equally bright sine-wave gratings 180° out of phase on a uniform background field. Each of the gratings was illuminated with a different monochromatic light, and the background field contained an equal-brightness mixture of the same two lights as in the gratings. The only modulation present in the stimulus was chromatic, and its amplitude could be varied by manipulating the relative intensities of the background and grating portions of the stimulus. Eleven different monochromatic lights, ranging from 450 to 650 nm. were used and each light was paired with all other lights in the set in a stimulus of this type. Detection thresholds for two subjects are shown. Threshold modulation amplitudes are viewed as an inverse measure of the chromatic difference between the lights in a pair.