The Impact of Background Luminance on the Perception of Chromatic Lightness

Background luminance drastically affects the color appearance of content. Modern display technologies allow for the reproduction of highly saturated colors with a perceived lightness looks “dull” or muted when super-imposed on backgrounds of higher luminance values. These perceptual effects can be predicted by analyzing the relationship between a color's chromatic contribution to perceived lightness and how it changes with background luminance. A two-alternative-forced-choice psychophysical lightness-matching experiment was conducted across different levels of background luminance. The Helmholtz-Kohlrausch (H-K) effect was found to have a significant impact on observers' expectations when assessing the lightness of a chromatic color under changing background luminance levels. The experimental results show that as background luminance is increased for highly saturated, low luminance colors, current models overestimate perceived lightness changes by more than double. To perceptually maintain the intent of creative content, color appearance models are needed to accurately predict chromatic lightness under changes to the background luminance level.