When the dark-adapted, totally color-blind eye is stimulated with pairs of single flashes of light of 0.15 millilambert (mL) luminance and of 10 msec duration the difference in size of the two electroretinograms evoked, as related to the dark interval between the stimuli, indicates exponential decay of suppression caused by the first stimulus. In these conditions the main component of the ERG is the "scotopic" b-wave.
Using pairs of light flashes of much higher luminance (150 mL, 20,000 photopic troland, 10 msec duration) for stimulation, the recovery of retinal function from suppression caused by the first stimulus is not only delayed by several hundred milliseconds, but also the time constant of the process is longer. In these conditions the ERG consists of both a negative and a positive component.
Elenius V. Recovery of Retinal Function From Suppression Caused by Flashes of LightElectroretinogram Measurements in Totally Color-Blind Eyes. Arch Ophthalmol. 1967;78(3):297-299. doi:10.1001/archopht.1967.00980030299007