Language of Light
Colour is a characteristic of light determined by the light’s spectral composition and the interaction with the human eye. Hence, colour is a psychophysical phenomenon, and perception of colour is subjective.
2.4.2 COLOUR PERCEPTION
The eye acts much like a camera, with the lens forming the image of the scene on the light-sensitive retina.
There are several kinds of light detectors, called rods and cones. The cones are grouped into three types, each responds to a portion of the spectrum, with peak responses corresponding to blue, green, and red light. The interaction of these groups is then responsible for the stimulus which is interpreted by the brain as colour. This widely accepted theory on colour vision is known as Trichromatic Theory.