Explain about the Color vision of human eye

The human eye can see about 150 different colours in the visible spectrum (400- 750 nm). Red, green and blue are said to be the primary colours and can be mixed to create different colours. Colour sense is the ability of the eye to perceive the specificity of wave length and the intensity of light. Colour vision occurs because of cones. The perception of colour also depends on the background. In dim light all colours are visualized as grey, due to the Purkinje shift phenomenon. Colour is better appreciated in photopic vision and should be tested for in broad daylight. There are three qualities specific to colour vision- hue, saturation, and brightness.