The influence of intermittent preadaptation upon subsequent dark adaptation was investigated for six preadaptation durations ranging from 30 seconds to 16 minutes. The rate of intermittence was one cycle/second and four ratios of light-to-dark (plus continuous light) were used. The preadaptation intensity was 1188 mL. The resulting dark adaptation curves show that an increase in the duration of intermittent preadaptation produces an elevation in initial threshold, a prolonging of dark adaptation, and a decrease in the rate at which dark adaptation proceeds. An increase in the light-time of the light-dark ratio will affect dark adaptation in a similar manner.
ELEANOR R. ADAIR, "Duration and Light-Dark Ratio of Intermittent Preadaptation as Factors Influencing Human Dark Adaptation," J. Opt. Soc. Am. 43, 22-24 (1953)