Webster's asserts that color is “a phenomenon of light or visual perception that enables one to differentiate otherwise identical objects,” and then goes on to say that the Latin root is celare, “to conceal.” It's a fine definition, because human perception of color is seamless to the extent that it conceals from us almost every causal detail. This talk will discuss common sources of light, the interaction of resultant source spectra with objects of interest, and aspects of how the resultant light is perceived as color. Particular emphasis will be placed on light modulated through interference and displays based on interferometric principles.