Abstract

Spectral luminous efficiency functions were measured by direct heterochromatic brightness matching and flicker photometry at the retinal illuminance levels, 1, 10, 100, and 1000 trolands with a 2° visual field. For all four subjects, as the retinal illuminance increases, the luminous efficiency curves for heterochromatic brightness matching broaden, but those for flicker photometry do not. It is understood through recent investigations that the sensitivity rises in short- and long- wavelength regions for heterochromatic brightness matching are consequences of the chromatic channels’ contribution to the brightness. From the present results, it is suggested that the contribution of the chromatic channels to the brightness increases as the retinal illuminance increases. Development of a model that makes quantitative predictions of the experimental results is in progress.

© 1988 Optical Society of America