Patent GB-1297653-A (GB)
IPC: C07D249/10
Filed: 1969-12-23
Abstract: 1297653 Bleach-fixing photographic silver halide materials ILFORD Ltd 22 Dec 1970 [23 Dec 1969] 62680/69 Heading G2C A stable photographic silver halide bleach-fix bath comprises an aqueous solution of an oxidizing agent which is strong enough to bleach the silver but is not strong enough to oxidize the silver halide solvent to any deleterious extent under normal processing conditions, a silver halide solvent which is either a water-soluble thiosulphate or a water-soluble thiocyanate and a water-soluble bleach-fix accelerator (a), (b), (c) or (d) as defined below. A photographic silver halide stop-fix bath comprises an aqueous acid solution of a silver halide solvent which is a water-soluble thiosulphate or a water-soluble thiocyanate and a watersoluble bleach-fix accelerator which has the formula (a):- R 1 R 2 N-N(R 3 )-C(Se)-NR 4 R 5  wherein one of R 1  and R 2  is H, alkyl, aralkyl, aryl or R 6 CO- wherein R 6  is H, alkyl, alkoxy or a heterocyclic group, or a group NR 7 R 8 -C(Se)- wherein R 7  and R 8  are each H or alkyl and the other of R 1  and R 2  is H or alkyl; R 3  is H, alkyl, aralkyl or aryl; one of R 4  and R 5  is H, alkyl, aralkyl or aryl and the other of R 4  and R 5  is H or alkyl, at least one of R 3 , R 4  or R 5  being H and there being not more than one aryl, aralkyl or hetercyclic group present in the compound or (b):- R 9 R 10 N-C(Se)-N(R 11 )-N(R 12 )-CO-X-CO-N(R 13 )- N(R 14 )-C(Se)-NR 15 R 16  wherein each of R 9 -R 16  is H or alkyl there being not more than 4 alkyl substituent groups in the compound and at least one of R 9 , R 10 , R 11 , R 14 , R 15  and R 16  being H and X is -(CH 2 ) m  wherein m is 0-4 or (c) a 1,2,4-triazole- 3-selenol wherein the 5-carbon atom carries H, alkyl, OH, amino, alkylamino, arylamino or aralkylamino and one of the N atoms carries H, alkyl, aralkyl or aryl or (d) a 5,5-bis-1,2,4- triazole-3-selenol wherein the triazole rings are linked directly or via a link - (CH 2 ) n  wherein n is 1-4 and wherein one N atom in each of the triazole rings carries H, alkyl, aryl or aralkyl. When the water-soluble bleach-fix accelerator has the formula:- R 41  NHNHC (Se)-NH 2  wherein R 41  is H, alkyl, aralkyl or aryl or R 42 CO- wherein R 42  is H, alkyl or a heterocyclic group or is a 1, 2,4-triazole-3-selenol wherein the 5-carbon atom carries H or alkyl it may be applied as an aqeous solution to an exposed and developed photographic silver halide material containing colour couplers which material may be simultaneously or subsequently treated with a stable bleach-fix bath (as defined above) comprising an aqueous solution of an oxidizing agent and a silver halide solvent which is a water-soluble thiosulphate or a water-soluble thiocyanate. The oxidizing agent may be a ferric chelate complex i.e. a coordination compound of the ferric ion and a compound comprising N and/or O-containing coordinating groups e.g. amino, heterocyclic N, carboxyl or carbonyl, such as ferric ethylenediaminetetraacetric acid complex. Many examples of the bleach-fix accelerators are given and they may be present in any treatment or wash bath between development and bleach fixing, e.g. the stop bath or stop-fix bath. They should not be present in the developer since they interfere with development, and for the same reason they should not be present initially in the photographic material before development. The water-soluble bleach-fix accelerators may be present in a wash bath which succeeds dye-bleaching and preceeds bleach-fixing in the silver dye-bleach process.