it can make an object appear larger or smaller, which is based on perceptive ability. Most people believe that the cue ball in billiard is larger than the eight balls.
Plate2 A. Billiard Cue Ball
Plate2 B. Protanopic Vision (Green-Blue)
Plate2 C. Normal Vision
In order to realize the dimension (depth of field) each person has to have normal vision. Ordinary human color vision has three dimensions of color corresponding to the blue-sensitive cones, the green-sensitive cones and the red-sensitive cones. Protanopic vision has only the green-sensitive and the blue sensitive dimensions (plates2 A, B & C).
