Color can be described through hue, saturation, and brightness. There are two main color models - additive RGB used in screens and subtractive CMYK used in printing. The HSV color space also describes colors through hue, saturation, and value. Precise color is specified through dominant wavelength, excitation purity, and brightness based on the electromagnetic spectrum of visible light frequencies between 400-700nm. Video color models are derived from analog TV methods and separate luminance from color. The eye sees yellow-green best and blue worst, and the CIE color space provides a three-dimensional representation of color perception.