The Effect of Spectral Power Distribution on the Perception of Scene Brightness in Nighttime Lit Streets

A laboratory experiment and two field experiments were conducted to investigate the effects of lamp spectral power distribution on perceived scene brightness in nighttime lit streets and reveal the mechanisms of the perception of scene brightness. The experimental results confirmed the Purkinje effect in which a scene appears brighter when it is illuminated by lamps with enriched short-wavelength radiation. The results also suggest that perceived scene brightness corresponds to mesopic luminances within the range of the experimental conditions and short-wavelength cones contribute to the perception of scene brightness to a limited degree at mesopic light levels.