Recombination in Latent Image Formation

Paper presented at a Symposium on “Fundamental Problems in Photographic Science” organized by the Science Committee of The Royal Photographic Society on 8-10 September 1975, in Oxford, England.

Abstract

Conflicting viewpoints concerning the importance of recombination in latent image formation are examined with respect to existing experimental evidence. Hole-electron pairs and, in certain circumstances, print-out silver specks are produced efficiently. In contrast, most, though not all, latent image centres form inefficiently. Reduction sensitization, which provides a means of detecting holes, increases efficiency of formation of latent image in emulsions chemically sensitized in various ways. This indicates the importance of recombination during exposure of the emulsions with no reduction sensitization. The wide breadth of most sensitivity distributions means inefficient utilization of absorbed photons. Neither variable critical size of latent image centres nor inefficient aggregation of silver or gold atoms is a likely explanation of this inefficiency, at least in certain circumstances. It is concluded that recombination has much influence on latent image formation. Loss of photoelectrons by electron acceptors can be a source of inefficiency, however.

Notes

Paper presented at a Symposium on “Fundamental Problems in Photographic Science” organized by the Science Committee of The Royal Photographic Society on 8-10 September 1975, in Oxford, England.