RGB Color Spaces

RGB primaries play an important role in building colorimetry. CIE color-matching functions are derived by CIE standard RGB primaries. Many imaging devices are additive systems, such as television and digital cameras that are based on RGB primaries, where image signals are encoded in a colorimetrical RGB standard. Moreover, colorimetrical RGB encoding standards are a frequently encountered representation for color reproduction and color information exchanges. This chapter presents an extensive collection of the existing RGB primaries. Their gamut sizes are compared. Methods of transforming between CIEXYZ and colorimetric RGB are discussed. A conversion formula between RGB standards under the same white point is also provided. The general structure and representation of the RGB color-encoding standard is discussed. Several important RGB encoding standards are given in Appendix 4. Finally, conversion accuracies from RGB via CIEXYZ to CIELAB of these primaries are examined.