Lighting Design Glossary

Afterimage
Aftersensation
Photogene

(Term of physiology)

Look at a bright light for about half a minute and then look away. There will be a dark spot in your new field of vision, where the bright light was a moment before. This lingering visual impression is called afterimage, aftersensation, or photogene.

The human eye continuously converts light energy into signals travelling through the nervous system. The visual system will reduce the transmission in highly exposed areas after a while. After that exposition is removed, this results in the perception of an inverted image, both in brightness and color.