Effect of Background Lightness on Contrast and Assimilation

Von Bezold type of assimilation was observed under various conditions in which the widths of line and space and the reflectances of line, space and background were varied systematically. The results supported “differential stimulation” and “area-luminance” hypotheses proposed by Helson. The important findings were that the effect not only depended upon the relations between line and space reflectances but also was determined by the reflectance of background. Even when the reflectances of line and space remained constant, depending on the reflectance of background, the effects of assimilation and contrast could be reversed. From the present results the “bipolarity of responses” in the dimension of lightness was discussed from a stand point of the effectiveness

Contrast (vision) · Geometry · Lightness · Line (geometry) · Luminance · Optics · Physics · Reflectivity · Space (punctuation) · Color perception and design · Computer Science · Mathematics · Remote Sensing and Land Use