Colour rendering in monitors or projectors uses RGB, a combination of red, green, and blue colours (at wavelengths of 630, 530, and 450 nm), to display a wide range of colours. Each displayed colour depends on the strength of these three colors and is expressed in either a percentage or a number of bits. For an 8-bit RGB output signal from a PC card, the range of these colour components is assumed to be from 0 to 255, and for special editing cards, a limited range of 16 to 235 is sufficient. The RGB model can be represented as a cube, with the vertical edges representing the strength of the primary colours. Each point in this cube then displays the value of the resulting colour using the coordinates.
For video or digital photos, the YCbCr encoding method is used. The colour pixels are described by three basic colour components: Brightness (Y), Cb Difference Component (BY), and Cr Difference Component (RY). YCbCr is not an absolute colour model, and the colour display depends on the current use of the RGB colours in the signal.