Editing Afterimage (section)

==On empty shape==
<!-- "Color dove illusion" redirects here, so do NOT remove the illustration -->

An afterimage in general is an optical illusion that refers to an image continuing to appear after exposure to the original image has ceased. Prolonged viewing of the colored patch induces an afterimage of the [[complementary color]] (for example, yellow color induces a bluish afterimage). The "afterimage on empty shape" effect is related to a class of effects referred to as [[contrast effect]]s.{{Citation needed|date=January 2012}}

In this effect, an empty (white) shape is presented on a colored background for several seconds. When the background color disappears (becomes white), an illusionary color similar to the original background is [[perceived]] within the shape.{{Citation needed|date=January 2012}} The mechanism of the effect is still unclear, and may be produced by one or two of the following mechanisms:

*During the presentation of the empty shape on a colored background, the colored background induces an illusory complementary color ("induced color") inside the empty shape. After the disappearance of the colored background an afterimage of the "induced color" might appear inside the "empty shape". Thus, the expected color of the shape will be complementary to the "induced color", and therefore similar to the color of the original background.
*After the disappearance of the colored background, an afterimage of the background is induced. This induced color has a complementary color to that of the original background. It is possible that this background afterimage induces simultaneous contrast on the "empty shape". Simultaneous contrast is a psychophysical phenomenon of the change in the appearance of a color (or an achromatic stimulus) caused by the presence of a surrounding average color (or luminance).