Chrominance

In digital-video and still-image color spaces such as Y′CbCr, the luma and chrominance components are digital sample values.

[1] Valensi's patent application described: The use of two channels, one transmitting the predominating color (signal T), and the other the mean brilliance (signal t) output from a single television transmitter to be received not only by color television receivers provided with the necessary more expensive equipment, but also by the ordinary type of television receiver which is more numerous and less expensive and which reproduces the pictures in black and white only.

Previous schemes for color television systems, which were incompatible with existing monochrome receivers, transmitted RGB signals in various ways.

Depending on the video standard, the chrominance subcarrier may be either quadrature-amplitude-modulated (NTSC and PAL) or frequency-modulated (SECAM).

In NTSC and PAL, hue is represented by a phase shift of the chrominance signal relative to the color burst, while saturation is determined by the amplitude of the subcarrier.