Effect of observer metamerism on colour matching of display and surface colours

Abstract

We studied the individual variability of asymmetric metameric colour matching between computer displays and object colour stimuli in conditions typical for the surface colour industries. Using two different computational techniques, we assessed the contribution of observer metamerism to this variability. In the studied conditions of spatially separated computer display and surface colour stimuli, this contribution was found to be insignificant for all colours but neutrals. In the chromaticness plane, the range of matches made by different observers practically coincides with the range of matches made by an individual observer. Consequently, we conclude that in the task of matching spatially separated display and surface colours, the range of matches made by a group of observers cannot be determined from variations in their colour-matching functions, and thus the paradigm of the Standard Deviate Observer is shown to be inapplicable to the studied conditions. We suggest that individual variability in these conditions is governed by mechanisms of chromatic discrimination, and can be modeled by advanced colour difference formulae with suitably adjusted parametric coefficients.

Adaptation and colour matching of display and surface colours

“…The details of the experimental conditions and the colour matching procedures are described in a companion publication. 16 …”

“…In a series of two papers, 16 we have described a study into the practical effects of observer metamerism and additivity failures, a study which has began as a research in basic colorimetry. We saw our target as the development of a new standard deviate observer.…”

“…By the end of the first experiment 31 we knew that we did not need any more data: the set from the Stiles and Burch study 7 provides all the information we need. The second experiment 16 taught us that a new SDO in not needed-at least for cross-media colour matching: observer metamerism does not contribute much to variations in colour matches of spatially separated stimuli. Results shown in this paper suggest that in the conditions of soft proofing, colour matching itself does not seem to operate according to the classical metamerism model.…”

Supplementary dataset for color difference evaluation

“…It requires also a larger set of color samples around color centers considered. In a previous study 9 we defined 26 samples, along 13 directions and by symmetry two sides, for each of these color standards (center). In order to find a compromise between the number of samples to be assessed by each observer and the number of samples necessary to compute the perceptibility thresholds associated with a color center, we propose to assess only 13 samples (i.e.…”

“…This problem is related to the problem of virtual proofing, i.e. of color matching of display and surface colors 9 . Other problems have been also pointed out by other studies regarding computation errors in color-difference formulas due to some discontinuities for various values of hue and of chroma.…”