Superfine grain developers

When exposed silver halides are reduced to metallic silver via the development process, there is always a degree of extraneous, unexposed silver halide that remains attached. Fine grain and superfine grain developers make use of solvents to dissolve as much of the extraneous silver halide as possible. The more efficient the solvent action of the developer, the finer the grain. 

Glycin, used in combination with ppd (Formulas Superfine-Grain Developers DuPont No. 3 Superfine-Grain Developer), makes a fine-grain developer with improved emulsion speed and faster rate of development. Unfortunately, because of the presence of ppd, it still suffers from the unpleasant side effects of high toxicity and staining. 

As far as the general composition of superfine grain developers, nearly all of them have a high sodium sulfite content as sodium sulfite is an effective silver solvent. For an alkali, they use small quantities of either carbonate or borax in order to minimize the energy of the developer and produce a finer grain. FX 10 uses a buffering mixture of borax and boric acid, whereas Windisch Superfine Grain Developer uses sodium metabisulfite to reduce the pH of the sodium sulfite. 

Notes p-Phenylenediamine is the classic superfine-grain developer. Besides the cautions that follow, it requires strong overexposure of the film and a very long developing time, often twenty minutes or more, and even then the contrast of the resulting negatives is rather low. 

As a result, there have been efforts to replace p-phenylenediamine with other agents. One of the more successful is the Windisch Superfine-Grain Developer that uses o-phenylenediamine. This agent also has weak developing properties, but it works as a good solvent for silver halide. 

This formula is reputed to be the only true superfine-grain developer known not to cause a loss of emulsion speed. It is very sensitive to overexposure and overdevelopment. This developer may very well prove useful with tabular grain films. Try diluting it 1 3. 

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