Proper application of chromaticity gamut area metrics for displays.

The areal dimension in chromaticity diagrams is often used to evaluate the range of reproducible colors (or color gamut) of a display; however, its meaning is not fully understood. For consistent and meaningful color gamut comparisons, the metric needs a color space with a common chromatically adapted white point, which is not considered in legacy chromaticity gamut area metrics. This study demonstrates the validity of chromaticity gamut area metrics and clarifies the proper way to use the metrics by comparing the color gamuts of synthetic additive displays with a range of sampled RGB primaries with different white points. The study reports high correlations of 0.98-0.99 between the xy chromaticity gamut area and color gamut volume for additive displays with a common white point at 6500 K and above. However, using the "gamut rings" 2D visualization method, this study also demonstrates that use of different white points cause a failure of the chromaticity gamut area metric.