Literature Review of the Herschel Effect

Abstract

The Herschel effect is reviewed and shown to be divisible under three headings:-(a) Spectrally sensitized Herschel effect in which light is absorbed by adsorbed dyes, (b) the sensitized Herschel effect, and (c) the normal Herschel effect. In (b) and (c) the light is absorbed by latent-image or fog nuclei: the light causes the ejection of a photo-electron which may be trapped by another latent image speck leading to a redistribution of the latent-image. This is the normal Herschel effect. Alternatively the electron may be trapped by a suitable oxidant which leads to a photo-oxidation of the latent image; this is called the sensitized Herschel effect.