The dark adaptation of two subjects was measured following pre-exposures that changed from zero to maximum intensity and the reverse, from maximum to zero, as well as for equivalent unchanging pre-exposures. Three intensities and four durations of pre-exposure were investigated. The main effects found were between the two changing conditions: for most of these the zero to maximum intensity resulted in higher initial thresholds and longer times to reach the final dark-adapted threshold than the equivalent condition in which the pre-exposure was from maximum to zero.
F. A. MOTE and LYMAN M. FORBES, "Changing Pre-Exposure and Dark Adaptation," J. Opt. Soc. Am. 47, 287-290 (1957)