Abstract

Low-intensity reciprocity-law failure in photographic exposure represents an inefficiency arising from the regression of the latent image in its early stages of growth. Evidence has been given to show that the stable sublatent image requires for its formation the action of two or more quanta in a small critical time period, τ. A new method for evaluating this critical time period by intermittent exposures is described.

Experiments carried out on four commercial emulsions showed approximately equal τ periods of the order of 3 seconds. Studies were also made on three experimental emulsions to determine the effect of certain types of chemical sensitization on the critical τ period. These experiments were carried out for both the surface and the internal latent image by means of varied development procedures. The critical τ period varied between 3 and 10 seconds for the surface image and remained essentially constant at about 4 seconds for the internal image. Results indicate that chemical sensitization increases the critical τ period of the surface latent image and slightly decreases the critical τ period of the internal image.

© 1954 Optical Society of America

Low Intensity Reciprocity-Law Failure in Photographic Exposure: Energy Depth of Electron Traps in Latent-Image Formation; Number of Quanta Required to Form the Stable Sublatent Image*†

J. H. Webb
J. Opt. Soc. Am. 40(1) 3-13 (1950)

Remarks on the Critical Time Period and the Schwarzschild Exponent in Photographic Processes

Jurgen Stock
J. Opt. Soc. Am. 46(1) 17-21 (1956)

Low Intensity Reciprocity-Law Failure in Photographic Exposure II. Multiplet-Quantum Hits in a Critical Time Period*†

J. H. Webb
J. Opt. Soc. Am. 40(4) 197-202 (1950)

An Experimental Study of Latent-Image Formation by Means of Interrupted and Herschel Exposures at Low TemperatureMeasurements of Reciprocity Law Failure at Low Temperature*

J. H. Webb and C. H. Evans
J. Opt. Soc. Am. 28(7) 249-263 (1938)

Number of Quanta Required to Form the Photographic Latent Image as Determined from Intermittent Exposures*

J. H. Webb and C. H. Evans
J. Opt. Soc. Am. 31(5) 355-357 (1941)