Picture Composition, 2nd Edition

14

Colour

How the eye sees colour

Colour vision is made possible by cones on the retina of the eye, which respond to different colours. The cones are of three types sensitive to certain bands of light – either green, red or blue. The three responses combine so that, with normal vision, all other colours can be discerned. There is a wide variation in an individual's receptor response to different colours but many tests have established an average response (see Figure 14.1).

Colour television adopts the same principle by using a prism behind the lens to split the light from a scene into three separate channels. Colour analysis in the camera will give the appropriate red, green and blue signals according to the spectral energy distribution of ...