Abstract

In the majority of studies of the Bezold–Brucke phenomenon, the observers have matched spectral stimuli of disparate luminance in hue by a wavelength adjustment. We used an asymmetric matching technique to match stimuli of disparate luminance in hue and saturation. We used a PIXAR imaging system to generate 28 equiluminant (110 effective td) colors on a Sony monitor. Two rectangular stimuli (1.3° × 2°) were presented, one to each eye, in a haploscope. One stimulus was reduced in luminance by placing a 1-log-unit filter before one eye. The observer adjusted the hue and saturation of the brighter stimulus until the two patches looked chromatically identical, although of different brightness (as if a mesh curtain obscured the dimmer side). One match per color was repeated on three separate days. The entire experiment was performed with a dark surround and with an equiluminant surround. With a dark surround, the matched colors were set redder or greener, consistent with the Bezold–Brucke phenomenon for spectral colors. Additionally the saturation was reduced for reds and greens. With an equiluminant surround, only desaturation was required.

© 1992 Optical Society of America