Use of Arrhenius Testing to Determine Thiosulphate Tolerance in Silver Halide Black-and-White Materials

Abstract

Most of the existing ANSI standards for archival black-and-white silver halide materials specify a very low residual Thiosulphate ion limit. The experiments on which these limits were based were run in the 1930’s and used extremely high relative humidities. In general. we believe that the products tested can tolerate more thiosulphate than the original standards allowed. The current philosophy in testing by the ANSI/ASC Task Force on Thiosulfate Tolerance and Image Stability is to rUn Arrhenius tests at humidities slightly above those in the storage recommendations. The accelerated keeping tests (lower RH-high temperature) beillg proposed are based on the Arrhenius work. In addition to archival keeping criteria, a set of thiosulphate ion limits and a battery of temperature-accelerated tests are being generated for medium-term and long-term keeping.