Dependence of the Herschel Effect upon the Surrounding Gas Medium

Abstract

THE Herschel effect—the weakening of the latent photographic image by means of light—is observed, as a rule, in the red and infra-red region of the spectrum. Recent investigations, however, show that under certain conditions the Herschel effect is observed in regions of the spectrum, where usually a normal photographic effect prevails. If, then, the Herschel effect is stimulated by the parallel reaction which accompanies the main photographic process, it is reasonable to suggest that the surrounding gas medium is involved in the reaction.