after-image

(redirected from after-images)
Also found in: Dictionary.
Related to after-images: positive afterimage

af·ter·im·age

, after-image (af'tĕr-im'ăj)
Persistence of a visual response after cessation of the stimulus.

after-image

A visual negative impression of a bright object or light, which persists for a few seconds after the gaze is shifted or the eyes closed. Persistence of a positive image after moving the eyes implies a potentially serious neurological defect.

after-image 

Visual sensation persisting after the original stimulus has been removed. If observed in darkness following stimulation by a high intensity, brief duration light source, seven different after-image phases are frequently noted. The first phase, also called Hering's after-image, is a positive after-image and it is followed by a negative after-image. After a short interval (less than half a second) a second positive after-image, called Purkinje after-image or Bidwell's ghost, appears, the character of which depends upon the conditions of adaptation, the colour of the stimulus and the retinal region stimulated (best in the periphery). Afterwards, a second negative after-image is sometimes observed followed by a third positive after-image, called Hess after-image. After a long dark interval, a third negative after-image may appear followed after another long dark interval by a fourth positive after-image. If the light stimulus is of moderate intensity, the last phases will be absent. See Emmert's law; after-image test; after-image transfer test.
complementary after-image An after-image in which the colour is complementary to the colour of the original stimulus.
Hering's; Hess after-image See after-image.
homochromatic after-image An after-image in which the colour appears the same as in the original stimulus.
motion after-image See waterfall after-effect; Plateau's spiral.
negative after-image An after-image in which the light areas of the original stimulus appear dark, the dark areas appear light and the coloured areas appear in a complementary colour.
positive after-image An after-image that appears the same as the original stimulus.
Purkinje after-image See after-image.
References in periodicals archive ?
Young, 'Art Spiegelman's Maus and the After-Images of History', in At Memory's Edge, 2000.
Composed of three novellas arranged chronologically but sharing neither characters nor specific location within Germany, this novel's treatment of the developing images and after-images precipitated by the Third Reich on its home territory serves to demonstrate once again that fiction can bear more truth than most studied attempts at historiography.
Another uses light projection to create strong after-images, so that the viewer sees something which is 'not there'.
One of the patients I saw was an electrician who was unable to work because he couldn't tell which screws he was looking at were real images and which were after-images.
Complementary colors were used next to each other to create after-images that enlivened the jazz mood.
It's not surprising then that despite the time and effort expended on the hiring process, after-images of candidates are often fuzzy and ambiguous.