light:Why do we see colour?

Why do we see colour?
 Renowned researchers, Thomas Young and Hermann von Helmholtz, contributed to the trichromatic or three colour theory of colour vision. According to Young, we see colour because of the actions of three different receptors.

 Helmholtz explained that all three types of receptors reacted to all colours, but in varying degrees, and that it was the total 'sensation' received by the brain that determined the colours actually seen.

 Another theory was put forward by Ewald Hering. He theorized that the retina's receptors are mere absorbers of light, and that colour discrimination begins in the coding mechanisms located farther along the optic system. Instead of colour being comprised of three basic colours, he suggested humans perceive colour based on six primary colours. This theory is widely accepted today.