Colour Difference Evaluation

For a pair of homogeneous colour samples or two complex images viewed under specific conditions, colour-difference formulas try to predict the visually perceived (subjective) colour difference starting from instrumental (objective) colour measurements. The history related to the five up-to-date CIE-recommended colour-difference formulas is reviewed, with special emphasis on the structure and performance of the last one, CIEDE2000. Advanced colour-difference formulas with an associated colour space (e.g., DIN99d, CAM02, Euclidean OSA-UCS, etc.) are also discussed. Different indices proposed to measure the performance of a given colour-difference formula (e.g., PF/3, STRESS, etc.) are reviewed. Among current trends on colour-difference evaluation, it can be mentioned the research activities carried out by different CIE Technical Committees (e.g., CIE TC’s 1-55, 1-57, 1-63, 1-81 and 8-02), the need of new reliable experimental datasets, the development of colour-difference formulas based on IPT and colour-appearance models, and the concept of “total differences,” which considers the interactions between colour properties and other object attributes like texture, translucency, and gloss.