It continues with describing the various types of color vision defects. It then presents a number of design aids and concludes with some general design guidelines. Color Vision Color is a visual sensation produced by electromagnetic radiation incident on the retina. The segment of the electromagnetic spectrum that can be perceived by humans is called the visible spectrum. The retina contains two types of photoreceptors, rods and cones , named after their shapes.
Cones are mainly responsible for color perception.
There are three types of cones, commonly referred to as red, green and blue cones. Color Vision Deficiencies Normal color vision is described as trichromatic . This term originates from color-matching studies. In color matching experiments, trichromats can match any color by a mixture of three primary colors. There is a considerable amount of variance in color-matching abilities of normal trichromats.