Sensitivity of the retinal cones

The third consideration in human colour vision is that of the eye and brain combination. This is exceedingly complex. A great deal remains unknown about the subject but working hypotheses have now been formulated which, at least, enable colour science to match and control colour in the colour using industries such as textiles, paints and plastics.

There are three basic requirements of colour. A light source, the selective absorption through the spectrum of the coloured object and the retinal sensitivity and integrating system of the eye and brain.

The following diagramatic representation of how we see a colour is, in a simplified form, the basis of operation of colour measuring instruments and systems.

The Tungsten light falls upon the green colour where it is modified by the selective absorption of the green dye or pigment and then passes to the red, green and blue retinal receptors where the excitation is in proportion to energy at each wavelength. The resultant signals are passed to the brain where the integration of a single colour sensation is made from the separate trichromatic signals.