Chemical Economics of Spray Processing

The rates of aerial oxidation of negative and positive motion picture developers in a pilot spray-developing cabinet, employing small and large reservoirs of developer, were measured and compared with the rates for three other typical circulation systems involving varying degrees of aeration. The wastage of chemicals in the spray cabinet depended upon the volume of developer circulated. In the case of D76d developer the wastage in the spray machine could be less than that in normal systems involving average aeration providing that the volume of circulating developer was sufficiently small. In a positive developer at pH 10.5 the wastage was from 2 to 6 times as much as that in the normal systems, depending upon the volume of developer used. — It was found that the rate of loss of chemicals from developers of pH below 10.0 reached a maximum on increasing the degree of aeration. At low pH's the maximum was reached at a low degree of aeration, thus accounting for the possibility of making economical use of spray processing in the case of D76d. At pH 10.5 no maximum rate of loss was reached on increasing the aeration. — The rate of loss of the developing agents was found to vary inversely with the sulfite concentration. It was not affected by the presence of colloidal silver, or by traces of copper or dye.

Print ISSN

0097-5834

Published

1949-12

Content type

Original Research

DOI

10.5594/J11676