Afterimages or aftereffects of visual stimulation may be either positive or negative. Negative afterimages are the opposite or the reverse of the original experience. More common and longer lasting. Positive afterimages are caused by a continuation of the receptor and neural processing following stimulation. Rare and brief.
Color blindness is the partial or total inability to distinguish colors.
Flag won t work if you are color blind. Color Weakness-can t distinguish pale colors. Confusion between green and blue most common form. 500 cases total color blindness. Critical for understanding spoken language.