Barry Britton


The Influence of iodide released during development on the course of development was Investigated by transferring known amounts of iodide to Kodak Panatomic X Film and Eastman Fine Grain Release Positive Film (Cine Positive) after exposure and before development. Iodide was transferred to the films being tested by soaking dry Bimat web material in potassium iodide solutions and contacting this to the film for fifteen minutes. The transfer of iodide in the Bimat to the film being tested was found to be essentially complete. The iodide reacted with the grains to convert silver bromide to silver iodide. The silver iodide thus formed appeared to be in a separate silver iodide phase (determined by spectrophotometric analysis) rather than forming a mixed crystal. Known amounts of iodide were transferred to the test films and developed for various times using DK-50 developer, a developer similar to DK-50 but with a higher pH, and also a hydroquinone developer (H2Q). Acceleration of Cine Positive development by iodide for the hydroquinone developer was noted for low concentrations of iodide (Lainer Effect). In general, development retardation was observed for the two Metol-hydroquinone developers. However, Panatomic X developed in hydroquinone showed pronounced retardation for the same amounts of transferred iodide. Development time series with Cine Positive film were used with DK-50 and H2Q developers to investigate the Influence of the iodide transfer on the induction period and developability of the emulsions. The iodide appeared to shorten the induction period of the hydroquinone developer which could account for the development acceleration (Lainer Effect) which was encountered. The noted acceleration by iodide of Cine Positive film developed in the hydroquinone developer was shown to be true acceleration and not a permanent gain in developability. Retardation of development, however, was shown to Increase with prolonged development for both developers, which provides a possible explanation for edge effects which do not disappear with prolonged development.

Library of Congress Subject Headings

Photography--Developing and developers

Publication Date


Document Type


Department, Program, or Center

School of Photographic Arts and Sciences (CIAS)


Carroll, Burt


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