Photographic Processing with One-Time Use of Solutions

Paper presented at the Symposium on “Processing Technology” organized by the Science Committee on 12-14 May 1965 in London.

Abstract

Most industrial processing machines, in the motion-picture laboratories, as well as in the large photofinishing stations, tend to be very large and to contain hundreds of gallons of solutions. This tendency seems to be right when considering the high chemical inertia resulting from such big volumes, but its corollary is the progressive and unrelenting chemical evolution of the solutions. So as to avoid this an artificial equilibrium is maintained by continuous replenishing with a suitably compounded solution, and an overflow of used liquid. This method is not very economical, and requires a rigorous chemical control and leads to tank formulae which are not necessarily the most suitable for the emulsion to be processed.

One-time use of solutions, on the contrary, allows the chemical equilibrium to be established by the initial formula itself, which can, therefore, be exactly adapted to the emulsion considered. This system, which makes chemical control unnecessary, is very economical provided that the overflowing solution volume is entirely exhausted, which is true only for a high ratio of processed surface to solution volume.

Notes

Paper presented at the Symposium on “Processing Technology” organized by the Science Committee on 12-14 May 1965 in London.