Effects of Background Illumination and Target Contrast on Flashblindness Recovery Time

Seven subjects were shown a series of Landolt Cs with gaps oriented toward one of eight compass directions. After a randomly occurring flash, the subjects were asked to identify the gap orientation of the target. A tungsten-halogen lamp was used as the flash source. The duration was 100 msec and the luminance was 60000 foot-lamberts. Five background luminances (16,62,120,230, and 575 foot-lamberts) and four target contrast ratios (0.1,0.2,0.3 and 0.5) were used in this experiment. Results show recovery times at the 0.1 contrast level differ significantly from those obtained at the other levels regardless of background. Recovery times on the 16 foot-lambert background level were significantly different from all other backgrounds regardless of contrast. There were no differences between recovery times at the other constrast levels or background luminances. (Author)