The
RG or
red-green color space is a
color space that uses only two colors,
red and
green. It is an
additive format, similar to the
RGB color model but without a blue channel. Thus, blue is said to be out of
gamut. This format is not in use today, and was only used on
two-color Technicolor and other early color processes for films; by comparison to a full spectrum, its poor color reproduction made it undesirable. The system cannot create white naturally, and many colors are distorted.