Abstract

The brightness of a chromatic flash is a joint function of its luminance and chromaticity.¹ The concomitant change in brightness and hue response with changes in luminance and chromaticity suggests a marked interaction between chromatic and achromatic coding systems. Bowen and Nissen¹ did not find the wavelength-dependent Broca-Sulzer effect under hue substitution using nonunique hues, in which a flash represents chromaticity modulation without luminance modulation. However, the present data showed the chromatic Broca-Sulzer effect under both hue substitution (test and background with 5 cd/m²) and increments (background with 0.5 and 1.6 cd/m²) paradigms using unique hues as stimuli. The unique hues (blue, green, and yellow) were measured beforehand and they are the loci of equilibrium points for opponent coding systems. The methods employed were scaling and signal detection procedures. The results showed a wavelength-dependent Broca-Sulzer effect.

© 1986 Optical Society of America