Processing solns. for black and white reversal processing - of microfilm etc. using high purity components to increase bath life and film quality

摘要

Processing baths used are of known compsn. but include components of specified purity. The process stages and baths used as follows: (a) first developer contg. 1-phenyl-3-pyrazolidone (I) and benzotriazole (II) together with potassium thiocyanate of chemically pure (CP), ultra-pure (UP) or analytical grage (AG), and NaOH of CP grade; (b) standard first rinse; (c) bleach bath contg. AG grade H2SO4 with a density of 1.83-1.84 and CP, UP and AG grade potassium bichromate; (d) standard clearing bath; (e) second developer contg. (I), (II) and CP grade NaOH; and (f) second rinse bath contg. triethanolamine lauryl sulphate. The remaining components in the baths are of photographic quality. The water used in the baths is pref. treated as follows: (i) dimineralisation with =1 ion exchanger, (ii) ultrafiltration, (iii) passage over a synthetic resin or addn. of EDTA and (iv) treatment over active carbon of mineral origin. Process gives high quality microfilms and duplicates of excellent clarity. The compsns. are more stable and larger numbers of microfilms can be processed without loss of quality. The build-up of salt deposits on the processing equipment, rollers, etc., is reduced, which gives reduced cleaning problems.