Effect of Illuminant on Colour Perception Concerning the Simulation of Colour Deficiencies

Normal human colour vision relies on 3 different cone photoreceptors (L, M, and S) in the retina and 2 opponent processes: red-green and blue-yellow. However, the exact hue perceived when observing an object is dependent upon three main factors, namely the genes encoding the opsins present in the observer’s eye, the spectral reflectivity of the object as well as the spectral composition of the incident light, also known as the illuminant. By controlling the composition of the illuminant, the amount of available light that can be reflected by an object can be controlled, which in turn affects the size of the observer’s colour gamut. By choosing illuminant spectra mostly/only containing colours that are most prominent to people affected by colour deficiencies, we can replicate the reduced colour gamut that they observe. Conversely, this technique can also be used to enhance certain colours and equalise the brightness of hues across the spectrum.