RGB model
A large percentage of the visible spectrum can be represented by mixing red, green, and blue colored light in various proportions and intensities. Where the colors overlap, they create secondary colors--cyan, magenta, yellow--and white.
RGB colors are also called additive colors. Additive colors are created by mixing spectral light in varying combinations. Adding all colors together creates white--that is, all visible wavelengths are transmitted back to the eye. Additive colors are used for lighting, video, and monitors. Your monitor, for example, creates color by emitting light through red, green, and blue phosphors.
Additive colors (the RGB model)