Iodide Analysis in an MQ Developer

R. M. Evans, W. T. Hanson, P. K. Glasoe

A method is described for the analysis of iodide in a developer involving precipitation of the halide with silver nitrate and oxidation of the iodide while it is in the form of solid silver iodide to iodate with chlorine water. The iodate is then determined polarographically. Quantities of iodide from 2.5 to 10 milligrams of potassium iodide were analyzed with an accuracy of 2–4 per cent. Thiocyanate in the developer interferes but it can be removed by boiling with strong sulfuric acid before precipitation. — Using this method of analysis it was shown that an equilibrium amount of iodide is obtained in a developer. Curves are given showing the attainment of equilibrium for development of Eastman panchromatic negative motion picture film, in Kodak D-76, and in Kodak D-16 developers, and Eastman positive motion picture film in Kodak D-16. The equilibrium value depends on the emulsion, the developer, the developed density, and perhaps other variables which will be investigated more thoroughly.

Print ISSN
Published
1942-02
Content type
Original Research
DOI
10.5594/J09929