Film Technology in Post Production, 2nd Edition

How colours are reproduced in film and television.

Film Processing

Additive and Subtractive Colour

Colour vision: additive colour

The retina of the eye is covered with light-sensitive cells, known as rods and cones. Rods are the more sensitive, but do not distinguish colours: cones fall into three classes, sensitive respectively to red, green and blue light, although the response curves overlap considerably. The brain is able to recognize any combination of signals from the three types of cone as evidence of a specific colour. For example, yellow light of wavelength 580 nm produces equal responses in the red and green cones.

We can produce the effect of any colour by adding together the right proportions of the three additive primary colours ...