 Helmholtz–Kohlrausch effect

The Helmholtz–Kohlrausch effect refers to a perceptual phenomenon in which the color of a light source appears to change relative to its surrounding colors. Specifically, it describes how the brightness of a color can influence the perception of its hue, particularly when that color is against a background of varying luminance or chromaticity. This effect, named after the physicists Hermann von Helmholtz and Wilhelm Kohlrausch, highlights the complex relationship between color perception, brightness, and contrast.