Synthetic Aged Developers by Analysis

The dropping mercury electrode is applied to the problem of analyzing aged photographic developers and new tests are described for elon and hydroquinone. The question of suitable tests for bromide is discussed and it is shown that the bromide test must be independent of chloride. Such a test is described. — Using these new technics and others it is demonstrated that it is possible and practical by chemical analysis alone to match exactly the photographic characteristics of an aged MQ developer. The only elements necessary for such an analysis are elon, hydroquinone, sulfite, salt concentration, pH, bromide, and iodide. The precision required for the proper analysis for each constituent has been investigated and is reported for three developer-film combinations. In general, the precision required is different for every combination. — It is pointed out that the results show there are no unknowns in aged developers, that they differ from the original formulas only in concentrations and in the presence of iodide as well as bromide. Several useful consequences are suggested.

Print ISSN

0097-5834

Published

1942-02

Content type

Original Research

DOI

10.5594/J09930