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Stephen Ivory, Alan Gilchrist; Perception of the highest luminance under extremely low illumination levels. Journal of Vision 2009;9(8):353. doi: 10.1167/9.8.353.
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© ARVO (1962-2015); The Authors (2016-present)
We tested the claim by anchoring theory that the highest luminance in the visual field always appears white, using Mondrian patterns under extremely low illumination. Observers were brought into a very dark lab and seated in front of a very dimly illuminated Mondrian that contained the highest luminance in the room. Observers first reported which patch appeared to be the brightest and then gave a verbal description of its lightness. Then the observer turned away and was shown a Munsell chart under bright illumination (403.9 cd/m2) and made a match from immediate memory. Ten naïve observers served in each experiment. In the first experiment, a 28 patch Mondrian pattern was presented on an LCD screen. Median match for the highest luminance patch (0.89 cd/m2) was Munsell 9.0. Experiment 2 tested a paper Mondrian with a truncated luminance range of 4:1 containing 24 patches ranging from only black and middle gray. Median match for the highest luminance patch (0.068 cd/m2) was Munsell 9.0. Experiment 3 tested a 33-patch paper Mondrian with a full black to white range (30:1). Median match for the highest luminance patch (0.055 cd/m2) was Munsell 8.5. Experiment 4 employed a 29-patch Mondrian with a full range and luminance levels in the scotopic range. Most of the patches were colored and the highest luminance was 0.001 cd/m2. No colors could be seen; indeed nothing could be seen for the first few seconds. Median match for the highest luminance was Munsell 8.5, regarded by most subjects as a white, if a poor white. The highest luminance rule holds across a vast range of illumination. It fails, if at all, only weakly, and that at extremely low luminance values.
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