An image encoding scheme with three bands, one for each primary color.
RGB is an image encoding scheme with three data bands, one for each visible, primary color - red, green, and blue. It is based on the additive color model of the same name. Each band contains cell values which are a measure of that color's contribution to the image. Only by combining all three bands can you get a 'true color' image. Note that some formats allow for a fourth 'alpha' band used to specify areas of transparency. The actual number of colors depends on the precision with which the values are stored - see color depth.