On Vision and Colors from a prism, however, the production of white can be demonstrated by using a mixture of colored light from each of the three main pairs of complementary colors: red – green, orange – blue, or yellow – violet. White can be produced from two complementary opposite colors when both of the external causes of the colors excite the same retinal place at the same time. Newton claimed that white could be produced by the aggregation of his seven prismatic colors. He erroneously considered color to be in light instead of in the eye. White is the result of the combination
On Vision and Colors the activity of the part that appears as color is necessarily conditioned by the inactivity of the complementary fractional part. The polar contrast between the active and inactive parts results in color. The vivid partial activity of the stimulated retinal spot is supported by that same spot's partial inactivity. Every color's darkness appears as its afterimage, or spectrum. Conversely, when looking at an afterimage, or physiological spectrum, the previously existing color is the darkening factor. Newton recognized that color is darker than white or light. He erroneously investigated light instead of the eye, the objective instead of the subjective. In