Abstract
With the aim to link color categorization to color perception we investigated whether the prototypes of color categories (focal colors) are more "colorful" than other colors. In this case, focal colors could work as perceptual anchors of color categories. We assessed "colorfulness" by estimating how many visible levels in saturation exist for the respective hue. For this purpose, we measured Just Noticeable Differences (JNDs) of saturation in CIELUV color space for hues of focal colors and of colors at the category boundary (boundary colors). We did so for all discriminable saturation levels available within the monitor gamut and extrapolated to the visual gamut. Then we counted how many JNDs fitted between the adaptation point and the visual gamut for each kind of hue. Our results for the yellow category show that focal yellow contains more discriminable levels of saturation than yellow-green, but similar amounts as yellow-orange. According to these results, focal yellow is not particularly "colorful". However, focal yellow yielded lower Weber fractions, and contained a higher number of discriminable colors when determining the upper limits of saturation by a maximally large circle in CIELUV space instead of the visual gamut. These results might indicate a particularly high sensitivity for focal yellow. However, in contrast to those for the visual gamut they depend on the color space in which equal saturation is defined. Hence, they might also be due to an inhomogeneity of CIELUV space that coincides with focal yellow. Measurements for other color categories will decide whether this pattern is characteristic for a particular sensitivity of focal colors or not.
Meeting abstract presented at VSS 2013