Colour is one of the most and obvious and pervasive qualifications in our environment. Blue is the most favored colour (terwagt & hoeksma, 1994) Most cases of colour blindness occurs at birth because of genetic absence of one or more type of cone receptors. The natural and human made world provides many colour signals that help us identify and classify thing: type of stone, ripeness of fruits. Helps facilitate perceptual organization: small elements become grouped perceptually into larger objects. How to tell one object from another. Te tell objects out in a scene survival. Describe colour by using, red, yellow, green, blue and their combinations: these colours are known as basic colours. Blue short wavelength end of spectrum. Yellow and red long wavelength of spectrm. Munsell book of colour, refered to as bible for designers 1225 colour samples. Pantone matching system current use 1200 colours. Perception of colour is associated with physical property of wavelength.