Progress in Monobaths

Paper presented at a symposium on “Processing Technology” organised by the Science Committee on 12-14 May 1965, in London.

Abstract

Monobaths have been known for over seven decades but Keelan's post-war researches may be said to constitute a watershed between purely empirical and scientific formulation. The kinetic studies of Klein and Swing and Berry, taken together with the contributions of Keelan and the work of two groups of researchers associated with Barnes and Jaenicke respectively, have led to the elucidation of the main mechanism of monobath processing. It is now known that (a) monobath processing will produce the deposition of excess silver as compared with conventional two-bath treatment, (b) not all of this deposited silver will have the same covering power. Researches hove shown that the deposition of excess silver is affected by exposure level, thiosulphate concentration and development time, and it is also known that the hitherto inadequately explained Miller effect is based on the difference in the relative covering powers of chemically and physically reduced silver. On the practical side, the availability of monobaths with adjustable thiosulphate levels, monobaths capable of rapid stabilization processing, or the discovery of reogents reducing sludge formation, may be considered as important developments, likely to establish monobath processing, in due course, as an acceptable, or even preferable, alternative to the methods at present used in the fields of technical and artistic photography.

Notes

Paper presented at a symposium on “Processing Technology” organised by the Science Committee on 12-14 May 1965, in London.