||Susanne Liebmann in the critical zone.
Discusses the career of Susanne Liebmann (1897-1990), who, while not the first to experiment with equiluminous color stimuli, was the first to reveal the breadth of phenomena that arise when colors are equated for luminance. Liebmann found that illusions disappeared at equiluminance because the stimuli no longer looked anything like the original figures (i.e., were no longer appropriate for inducing the illusions). She named the region near equiluminance the "critical zone" and proceeded to evaluate the nature of the perception of form and space in that zone. Other areas of equiluminance studied by Liebmann include the loss of accommodation; the fading, blurring, and filling in of images; and the loss of depth perception. Liebmann's paper on the "Behavior of colored forms with equiluminance of figure and ground" is appended. (PsycINFO Database Record (c) 2007 APA, all rights reserved)