: These are the most common type. They appear in colors complementary to the original stimulus. For example, staring at a green object will produce a magenta afterimage because the green-sensitive cones in your retina become fatigued, leaving only the red and blue signals (which combine to form magenta) to be processed when you look at a neutral surface.
While afterimages are usually normal physiological occurrences, abnormally long-lasting or intense afterimages are known as . According to the Cleveland Clinic , persistent afterimages can sometimes be associated with medical conditions such as: After image
: This theory explains why negative afterimages appear in complementary colors. It suggests that the visual system processes color in antagonistic pairs: red vs. cyan, green vs. magenta, and blue vs. yellow. : These are the most common type