Chromatic-Discrimination Ellipses with a Pair-Comparison Method for Different Neutral Backgrounds and Anchor Pair Colour-Difference Sizes

摘要

As stated by the CIE Technical Committee 1-28 (Parameters Affecting Colour-Difference Evaluation), the effect of background may be one of the most important parametric effects. Although there are several studies on this subject, neither a full range of light-to-dark neutral backgrounds nor a possible connection with the colour-difference size of the anchor pair employed have been reported. We have calculated CIELAB chromatic-discrimination ellipses at the five CIE centres using a CRT device, 5 neutral backgrounds regularly spaced between L~* 0 and 100, and 3 neutral anchor pairs having colour differences of 2, 5 and 10 CIELAB units. The calculated ellipses were compared using the V_(AB) coefficient proposed by Strocka (Colour Research & Appl. 8, 169-175, 1983). Preliminary results show that increasing the colour-difference size of the anchor pair, the effect of a background change on colour-discrimination ellipses becomes lower (30% for ΔE = 2 and 17% for ΔE = 10). In addition, on increasing the background lightness, the effect of the changes in the anchor-pair colour-difference on chromatic-discrimination ellipses is slightly less (19% and 14% for black and white backgrounds, respectively).