Experimental Study of the relation between intermittent and nonintermittent sector-wheel photographic exposures

Abstract

This investigation on the effects of intermittent sector-wheel photographic exposures was prompted by data obtained some years ago which were not in agreement with the results of other investigators. It is the accepted view that, compared with a continuous exposure, intermittance always causes a loss in photographic effect. The data shown here prove that the effect may be either a gain, a loss, or zero, dependent on the illumination. The illumination appears to control certain properties of the latent image not heretofore shown. When the latent image is formed by illumination above a certain level for the particular emulsion used, a growth of the latent image after exposure is found, and with the illumination below this level a fading of the image results.

Brightness enhancement in flickering light.

“…The principal similarity between them is that a photochemical reaction forms one link in a complex chemical cycle, and that in each case the cycle, although widely different in most respects, permits an enhancement phenomenon to occur. Data which may be interpreted as evidence of enhancement in photochemical cycles are not limited to photosynthesis and human vision, but they have also been noted for vision of arthropods by Mast, Dolley and others (23,15) and for photographic plates by Davis (14). Unfortunately, no apparent attempt has been made to link the arthropod data with the photochemical cycle, but there seems to be no reason for necessarily considering this effect for arthropods as being caused by the refractory period of the sense cells or of the nervous elements as proposed by Mast (23).…”