1. The scotopic visibility curve and cone intrusion.
- Author
-
Crawford BH and Palmer DA
- Subjects
- Color, Dark Adaptation, Humans, Photometry, Sensory Thresholds physiology, Photoreceptor Cells physiology, Visual Perception physiology
- Abstract
The scotopic visibility curves of two observers have been measured by determining their absolute thresholds for monochromatic lights and by direct comparison matching just above the threshold, in a 10 degree field with its centre 15 degrees above the fixation point. The results were all similar to the CIE scotopic curve. However, the threshold results in the long-wave part of the spectrum could be considerably modified by subliminal red and green lights. This is consistent with Drum's observations of sub-additivity at threshold. Above threshold, supra-additivity was obtained. A scotopic curve is evidently a non-linear combination of rod and cone responses which varies with the conditions of observation.
- Published
- 1985
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