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Measuring color matching differences between observers is an important means of investigating individual differences in human color vision. In this article, we introduce a new LED‐based visual trichromator with which we have estimated color matching functions and cone spectral sensitivities in a group of five normal observers. The trichromator has side‐by‐side semi‐circular matching fields that are illuminated by two spectrally tunable LED light sources, each comprised of 18 LEDs with center wavelengths ranging from 400 to 700 nm. We used Maxwell's method to derive a set color match. A fixed triplet of red‐green‐blue (RGB) primaries produced the white standard field of 120 cd/m2 in one field. The other field, the mixture field, was illuminated by one of 11 different triplets of lights with various center wavelengths. Observers adjusted the intensities of the triplets in the mixture field to match the white standard field. All matches were made for field diameters of 2° and 10° of visual angle to allow comparisons with colorimetric standards and were repeated five times. Calibrations and tests showed that the trichromator and the measurements were stable and repeatable. Grassmann's laws predict that at the 11 color matches the excitations in the three cone types should be the same. Consequently, we can use those matches and a model of how cone spectral sensitivities vary between individuals to estimate the three underlying corneal cone spectral sensitivities for each observer (and thus how they vary from the standard (or mean) observer). We find good agreement with the CIE 2006 standards, but our observers show small but consistent differences. [ABSTRACT FROM AUTHOR]

Chromatic adaptation is an important visual phenomenon that specifically influences color appearance under various illumination conditions. There were extensive studies investigating the impact of the illumination condition and the surrounding condition on chromatic adaptation. However, past studies hardly consider the properties of the stimulus object such as color, size, dimensions, etc. In this study, the impact of the size and dimensionality of the stimulus (target object) on the degree of adaptation was investigated. A series of achromatic matching experiments were conducted in a lighting booth, with the adapting field varying in chromaticity and the object varying in size and dimensionality, to collect corresponding color data. Results indicate that the properties of the stimulus, such as the dimensionality and size, can significantly influence the adaptation state, independent of illumination chromaticity. But to apply the results in the real application may be restricted to the specific setup (used in this study) with a separately illuminated stimulus, which needs further investigation. [ABSTRACT FROM AUTHOR]

A color rendition chart, the preferred memory color (PMC) chart, has been produced. It comprises 30 colored patches, divided into three groups: preferred memory colors, reference color‐gamut colors, and a gray scale. The main purpose of the new chart is to enable users to produce satisfactory preferred color reproduction using digital cameras, displays, and printing systems. The methods used to develop the various colors, and the color specification of each color are presented. Finally, several potential applications of the chart for the characterization of imaging devices, for the evaluation of image color quality, and for the calculation of color rendering indices for lighting are suggested. [ABSTRACT FROM AUTHOR]