Perceived Color Impression for Spatially Mixed Colors

Display devices adopt multiprimary pixels to represent chromatic images, and the individual primary pixels are discernible dimly within a certain range of spatial frequency. We systematically investigate the color impression of spatially mixed patterns of two colors from a barely discernible distance and show that the color impression differs greatly from their physically averaged colorimetric color. A large degree of luminance-enhanced perception is observed in all mixed color patterns, and significant chromatically enhanced perception occurs in the test of mixed monochromatic patterns. The color-enhanced perception inversely depends on spatial frequency and is not detected at all when the spatial frequency is more than 50 cycles per degree. However, when the patterns have excessively low spatial frequency, causing the pattern shape to be clearly recognized instead of being perceived as coarsely mixed color, the color-enhanced perception is suppressed. The strength of color-enhanced perception also depends on the contrast and width ratio between two colors, as well as hue value.