Wikipedia says that an afterimage is an optical illusion that occurs after looking away from a direct gaze at an image, and is closely related to the persistence of vision, which is the retention of an image in the retina. One of the most common afterimages is the bright glow that seems to float before one’s eyes after staring at a light bulb or a headlight for a few seconds.
If staring long enough at a primary colour, one will find these ghost images remain as the corresponding secondary colours in the eyes if then looking to a white, blank surface.
For example, if staring at the following, inverted image of the American Flag for thirty seconds, and then at a blank white sheet of paper … well, see for yourself.
See if you can find other examples of commonly used afterimages, or if you can find the corresponding primary or secondary of your favourite colour. You might want to also make an opposite of the dominant colours in your favourite space.
