Red helium–neon lasers were used commercially in Laser Disc players.
The use of red laser diodes became widespread with the commercial success of modern DVD players, which use a 660 nm laser diode technology.
On the color wheel long used by painters, and in traditional color theory, red is one of the three primary colors, along with blue and yellow.
Painters in the Renaissance mixed red and blue to make violet: Cennino Cennini, in his 15th century manual on painting, wrote, "If you want to make a lovely violet colour, take fine lac [red lake], ultramarine blue (the same amount of the one as of the other) with a binder" he noted that it could also be made by mixing blue indigo and red hematite.
Colors with a shorter wavelength, such as blue and green, scatter more strongly, and are removed from the light that finally reaches the eye.