Colour consistency metric proposed for LED lighting

French optical firm Gaggione has proposed a way to compare the evenness of colour in ‘white’ light beams produced by LED lighting – generally those with separate RGBW die as light sources. The aim is to produce a single number which sums up how even a beam will appear when shone on to a white surface, allowing different LED and optical combinations to be compared. “It is very difficult to quantify the quality of colour because everyone has a different way to perceive colour,” according to Gaggione. “We found it necessary to create a unit of measurement that enables the quantification of the quality of colour mixing in a scientific way.”