ABSTRACT
Colour television is only possible because the effect on the human eye of any spectral distribution of light energy can be simulated by the addition of three monochromatic light radiations. These radiations must be situated at the long-wavelength end of the visible spectrum (red), in the centre of the spectrum (green) and at the short-wavelength end of the spectrum. The mechanism of the human eye enables an addition of radiation at three discrete wavelengths to be observed as having a particular colour. Suppose there are three sources of light: red, green and blue, and that these sources are all projected simultaneously on to the same white screen. Since the light from any part of a scene can be synthesized by the addition of three primary colours, a colour television system may use three separate cameras to generate electrical signals corresponding to the quantities of red, green and blue light required.
