Simultaneous contrast
The (perceived) colours of objects can change when they are placed next to another colour. Simultaneous contrast is the tendency of a colour to induce its opposite in any of the perceived colour attributes, which results in shifts of hue, lightness/value and chroma (or vividness).
Simple definition: The way a colour looks to us can change depending on its neighbouring colours.
Expanded discussion: See David Briggs’ discussion on Simultaneous Contrast and Assimilation
Examples: The images below show you how the neighbouring colour changes the perceived colour of the diamonds.
Examples of simultaneous contrast, where the surrounding colours impact the colour of the diamonds. Images courtesy of Paul Green-Armytage.
Note that the Munker-White illusion and simultaneous contrast do not produce the same visual effect (i.e. the dark yellow appears comparatively darker on the top left when surrounded by white in the simultaneous contrast example, and comparatively lighter on the bottom left when juxtaposed with white in the Munker-White example).
A comparison of simultaneous contrast (above) and the Munker-White effect (below) using the same colour. Note that the lightness of the dark yellow areas is affected in the opposite sense between the two illusions (i.e. the yellow appears comparatively darker on the top left when surrounded by white in the simultaneous contrast example, and comparatively lighter on the bottom left when juxtaposed with white in the Munker-White example). Image courtesy of Maggie Maggio.
