RECOMMENDED COLOUR-INCONSTANCY INDEX

One of the parameters of greatest interest in the design and production of coloured objects is their colour (in)constancy, i.e. their change in colour appearance with change in illuminant. Serious practical problems attend the visual assessment of colour inconstancy. Several instrumentally based models have been proposed but none has proved sufficiently reliable for routine use in the coloration industries. The Colour Measurement Committee (CMC) recommends a recently developed method, named the CMC 1997 colour-inconstancy index, which is based on a chromatic adaptation transform, CMCCAT97, that outperforms all others and is being increasingly adopted in international standards. This paper summarises the development of CMCCAT97 and the results of its testing, and gives details of the calculations necessary to CMCCAT97 and the new colour-inconstancy index. Publication sponsored by the Society's Colour Measurement Committee