Colour Matching

In order to define the perceptual 3D space in a "standard" way, a set of experiments have been carried by having observers try and match colour of a given wavelength, lambda, by mixing three other pure wavelengths, such as R=700nm, G=546nm, and B=436nm in the following example.

Note that the phosphors of colour TVs and other CRTs do not emit pure red, green, or blue light of a single wavelength, as it is the case for this experiment.