Afterimage: Difference between revisions

1,159 bytes added ,  6 years ago
restore section deleted by a vandal on 19:07, 11 January 2009 (!)
(restore section deleted by a vandal on 19:07, 11 January 2009 (!))
[[File:Illusion movie.ogg|240px]]
Example movie which produces distortion illusion after one watches it and looks away. See [[Motion aftereffect]].{{Citation needed|date=January 2012}}
==Positive afterimages==
Positive afterimages, by contrast, appear the same color as the original image. They are often very brief, lasting less than half a second, and may not occur unless the [[stimulus]] is very bright. The cause of positive afterimages is not well known, but possibly reflects persisting activity in the [[visual system]] where the [[retina]]l [[photoreceptor cell]]s continue to send neural impulses to the [[occipital lobe]]<ref>[ Positive afterimages description]</ref>, suggesting that the experience of a stimulus can vary with the intensity of the stimulus.
As in most circumstances only very bright stimuli such as the [[sun (star)|sun]] produce positive afterimages, and a stimulus which elicits a positive image will usually trigger a negative afterimage quickly via the adaptation process. To experience this phenomenon, one can look at a bright source of light and then look away to a dark area, such as by closing the eyes. At first one should see a fading positive afterimage, likely followed by a negative afterimage that may last for much longer.
==Afterimage on empty shape==