A combined colour preference - colour rendering index

A combined colour rendering-colour preference index for complexion colours is proposed, having its maximum for a source, whose spectral distribution is equal to that of the reference source, but for other sources depends also on the components of the colour difference vector, i.e. lightness, chroma and hue differences. It is based on calculations performed in CIELAB space, using Nayatani type chromatic adaptation transformation to D65 reference illuminant and is backed by visual observations of preferred skin tones and comparative studies of different light sources.