Questions have been raised in dark adaptation experiments about the light adapting effect of the test flashes used to measure the course of dark adaptation. An experiment was undertaken to determine the allowable upper limit of the test stimulus. A series of one-fifth second flashes of a given intensity was presented to the observer after he had become dark adapted, and his recovery of the dark adapted state was determined. The net effects of the flashes were plotted for various values of flash intensities in a range several log units above the threshold.
EDWARD J. SWEENEY, "Effect of the Test Stimulus on the Measurement of Dark Adaptation," J. Opt. Soc. Am. 49, 667-667 (1959)