BS ISO 18901:2010 Imaging materials. Processed silver-gelatin-type black-and-white films. Specifications for stability
BS ISO 18901 is an International Standard which establishes the specifications for photographic films intended for the storage of records.
It is applicable specifically to films with a base of safety cellulose ester or polyester having silver-gelatin emulsions, processed to produce a black-and-white silver image by negative or full-reversal processing. It applies to film processed using a monobath that includes thiosulfate as the fixing agent, followed by a conventional wash. It also is applicable to silver films given a stabilizing treatment by partial or full conversion to silver sulfide, silver selenide or gold.
BS ISO 18901 is applicable to films having ultrasonic or dielectric (induction-heated) splices. It does not cover films with splices made of adhesive tape or solvent-type spIices..
BS ISO 18901 is not applicable to films with chromogenic black-and-white images, colour images of any type, or to films with a magnetic recording track. It does not apply to films with silver images produced by dry or thermal processing or by diffusion-reversal processing, or to films that have been processed by a monobath using means other than a thiosulfate-type fixing solution. It is not applicable to films where the silver salts are removed by means other than thiosulfate solutions.
BS ISO 18901 is not applicable to films to which lacquers have been applied.
Contents of BS ISO 18901:
Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Film base requirements
5 Processed film requirements
5.1 Storage conditions
5.2 Safety film
5.3 Amount of free acid
5.4 Tensile properties and loss in tensile properties
6 Requirements for the emulsion and backing layers of processed film
6.1 Layer adhesion
6.2 Emulsion flow
6.3 Blocking
6.4 Thiosulfate concentration
6.5 Residual silver compounds
7 Image-stability requirements
7.1 General
7.2 Radiographic films
7.3 Microfilms
7.4 Other films
8 Test methods
8.1 Identification of film base
8.2 Accelerated-ageing conditions
8.3 Determination of the amount of free acid
8.4 Tensile property test for processed film
8.5 Tape-stripping adhesion test
8.6 Humidity-cycling adhesion test
8.7 Emulsion-flow test
8.8 Blocking test
8.9 Residual silver compound test
8.10 Image-stability test
Annex A (informative) Washing and the effect of residual thiosulfate on the developed silver image
Annex B (informative) Effect of residual silver compounds on the developed silver image
Annex C (informative) Accelerated image-stability test for radiographic films
Annex D (informative) Accelerated image-stability test for microfilms
Annex E (informative) Accelerated image-stability test for aerial films
Bibliography