A red disk with a black dot in its center beside a blank white square with a matching dot, with instructions to stare at the first dot and then look at the second.

Concept · Relationships

Afterimages

An afterimage is a ghost color seen after staring at a color, usually close to its opposite: a strong red leaves a pale blue-green.

Steady looking tires the parts of the eye that respond to that color, so a white surface seen next looks tinged with its opposite. Chevreul called this successive contrast, because it unfolds over time rather than side by side. Goethe saw a girl in a scarlet bodice reappear on a white wall in sea-green.

Stare at the dot in the red disk for half a minute, then look at the blank square.
After long work on one strong color, rest your eyes before judging the next mixture.
Afterimages fade in seconds and vary between viewers, so they are only a rough guide.

Image: Made for this site · Original work