Newton was the first to point out that light is colorless, and that consequently color has to occur inside our brains. He wrote, “The waves themselves are not colored.” Since his time, we have learned that light waves are characterized by different frequencies of oscillation, and when they impinge on the retina of an observer, they set off a chain of neurochemical events, the end product of which is an internal mental image that we call color. The essential point here is: What we perceive as color is not made up of color. Although an apple may appear red, its atoms are not themselves red.
