ABSTRACT

Aftereffect The change in perception that occurs after looking at a bright and contrasty image, such as a line graphic on a video screen, and then looking away from it. For example, looking at a curved line for some time and then looking at a straight line can make that line appear curved and bending in the opposite direction. (See also Waterfall Effect.)

Afterimage The visual image that is experienced after looking at a bright and contrasty image for some time, and then looking away from it. The image is seen as similar in shape but complementary in color, or in the case of black-and-white images, reversed in tonalities. The more intense the light source used for looking at the picture, the longer the duration of the afterimage.