Color Appearance Mode Research Articles

Upper-limit luminance for the surface-color mode appearance.

A series of experiments were carried out to reveal determinants for the mode of color appearance by measuring the upper-limit luminance of a color chip for the surface-color mode. We used a CRT color monitor to present test and surround stimuli in the surface-color mode. The stimuli were composed of a three-by-three array of color chips on a gray background with a white frame. The observer increased the luminance of a center test color until it just ceased to appear in the surface-color mode. Our results show that this upper-limit luminance was different among test colors, but their brightnesses, calculated from the luminance and brightness/ luminance values, were almost the same and were slightly below the brightness of the white frame. The existence of the surrounding color chips affected the results, but their sizes and spatial arrangements did not. When all of the luminances of the surrounds changed equally, the upper-limit luminances of the test colors for the surface-color mode appearance changed by the same ratio. This result indicates that the brightness of a target was a determinant for selecting the mode of color appearance and that the brightest surround stimulus acted as a cue for determining the judgment.

表面色モード知覚のための限界輝度条件

The mode of color appearance gradually changes from surface-color mode to aperture-color mode as the intensity of the stimulus increases. We measured the upper-limit of luminance for the surface-color mode to find the determinants of mode perception. A subject adjusted the luminance of a test stimulus located at the center of surrounding stimuli so that it just started to appear as the aperture-color. The surrounding stimuli consisted of eight color chips and a white frame on a gray background, and they were either made using Munsell papers or presented on a CRT monitor. The results indicated that the upper-limit luminances was different in all the test colors. We also measured the brightness-luminance ratio (B/L) for each test color. The products of upper-limit luminance and B/L were almost equal for all test colors. A comparison of upper-limit luminance of our data and that derived from the optimal color for each test color also indicated less chromatic dependence. These results suggest that both brightness and optimal color may determine the transition from surface-color to aperture-color mode perception.

Revisitation of the luminance conditions for the occurrence of the achromatic neon color spreading illusion.

This paper develops the idea (Bressan, 1993) that neon spreading derives from the perceptual scissioning of ordinary assimilation color, a process identical to that occurring with nonillusory colors in phenomenal transparency. It is commonly held that the critical elements in achromatic neon spreading patterns must be of luminance intermediate between that of the embedding lines and of the background. The interpretation of neon spreading on the basis of color scissioning, however, predicts that neon spreading should also be observed for different luminance hierarchies, provided that these are compatible with transparency. This prediction found experimental support in the present work. The results suggest that (1) the widespread notion that chromatic and achromatic neon spreading must be mediated by separate mechanisms is unwarranted; (2) the widespread notion that color spreading in ordinary assimilation patterns and color spreading in neon patterns must be mediated by separate mechanisms is unwarranted; and (3) other than pointing to the way in which the overall organization of a scene affects the mode of color appearance, the neon spreading effect may not convey any extra theoretical relevance.