The word color is a general term for the qualities of hue, intensity, and value observed in pigment or light.
Color theory is based on the principal that color is light. When white light is diffused by a crystal prism, a spectrum of the entire range of pure colors (red, orange, yellow, green, blue, violet) becomes visible to the eye. Every color we normally see is light which has either been reflected from or transmitted by a colorant, such as a pigment or dye. Colors, because of their chemical structure, have the property of selectively absorbing and reflecting certain areas of the light spectrum. Example: If a colorant produces a visual sensation of red-violet (not in the spectrum), it has the property of absorbing all of the colored rays in white light except violet and red, which combine to produce the color we see.