Reciprocity failure in the region 10^-1 to 10^-4 second for nine photographic emulsions

Abstract

Reciprocity failure is defined as the failure of a photographic emulsion to obey the Bunsen-Roscoe reciprocity law for photochemical reactions. This law, set forth in 1862, stated that the product of a photochemical reaction depended only on the total light energy (exposure) producing the reaction, and was independent of the rate of application of the energy. Within fifty years of the publication of the law, its failure had been confirmed several times. It is concluded that reciprocity failure can cause a serious loss in speed when extremely short exposure times are encountered. The common films used in oscilloscope photography, such as Linagraph Pan and Linagraph Ortho, show a severe speed loss at very short exposure times. If the need for rapid processing dictates the use of very thin, highly hardened emulsions, those emulsions used must, in addition, be examined for reciprocity failure before their application to high -speed recording can be recommended. [TRUNCATED]