Theory of Light & Colour

Sir Isaac Newton discovered colour in light in 1666 by passing light through a prism and creating a rainbow on his wall. Then in 1802, a physician called Thomas Young proved that these colours all have a specific frequency and wavelength. His theory proposed that light is made up of three primary colours: red, blue and green, and that all other colours are formed by a combination of these three. This is the fundamental principle for colour photography.
 

The eye perceives light by the reflection and absorption of light by all objects. For example, a blue object will reflect blue light and absorb red and green light. Furthermore, a white piece of paper will reflect all colours of light and a black piece of paper would do the converse and absorb all frequencies of light.
The complimentary colours of the three primary colours red, blue and green in the visible spectrum of light are cyan, yellow and magenta respectively. The diagram on the following page illustrates the colour wheel for visible light. The colours next to each other in the colour wheel are considered to be colours in contrast such as blue and violet. Two colours that appear opposite to each other in the wheel are referred to as colours in discord e.g. red and cyan.