colour constancy

Color constancy is the psychological phenomenon where the perceived color of an object remains consistent despite changes in illumination. Our eyes and brains are adept at compensating for variations in the amount and spectral quality of light, allowing us to recognize familiar colors under different lighting conditions. For instance, snow appears white whether viewed in dim moonlight or bright sunlight.12

This constancy is a form of perceptual constancy, which helps us identify objects reliably. However, subtle color differences can sometimes be perceived differently under varying lights, a phenomenon known as metamerism. The intensity of illumination also influences color perception, leading to effects like the Purkinje shift at low light levels.12