Bezold Effect

The Bezold effect, named after the meteorologist Wilhelm von Bezold, is an optical illusion demonstrating how color perception is altered by the proximity of different colors, and how they effectively interact with each other.

The typical Bezold effect is represented with two squares, striped alternatively with the same solid foreground color, but one square has a white background, while the other has a different color. The observer has the impression that the foreground stripes are of different shades in the two squares, while they are actually the same color.

Bezold Effect: colors affect the perception of other colors in the same area

A colored Bezold effect: the pink squares look different in the two squares, but their color is the same

Animated Bezold effect: notice how the colored triangles seem to acquire a shade of the surrounding colors (especially visible in yellow triangles in the right square)