Method for processing silver dye bleach materials

Claim 2

In the method for processing silver dye bleach material wherein the process measures of 1. silver developing, 2. dye bleaching, 3. silver bleaching and 4. silver fixing are carried out in the sequence (1) to (4) with separate appropriate preparations for the individual stages, the step which comprises employing for silver bleaching an aqueous preparation (3) which contains a. a strong acid, b. a water-soluble iodide, c. a water-soluble organic nitro compound, d. a diazine compound in an amount of 0.2 to 5 gram per liter of preparation (3) and e. an anti-oxidant, only preparation (3) containing a nitro compound.

Claim 3

Process according to claim 1, which comprises using a silver bleach preparation (3) which contains sulphuric acid or sulphamic acid.

Claim 4

Process according to claim 1, which comprises using as the water-soluble nitro compound (c) an aromatic dinitro compound.

Claim 5

Process according to claim 3, which comprises using as the water-soluble nitro compound a dinitro benzene sulphonic acid.

Claim 6

Process according to claim 1, which comprises using as the diazine compound (d) a water-soluble pyrazine or quinoxaline compound with an absorption maximum below 450 nm and using as the anti-oxidant (e) a reductone.

Claim 7

Process according to claim 5, which comprises using as the diazine compound a) pyrazine without substituents or with 1 to 4 of the following substituents: methyl, ethyl or carboxyl, with at most two of any one of these substituents being present simultaneously, or b) a quinoxaline with the following substituents: a hydroxymethyl group in both the 2- and 3-position and the following substituents on the benzene ring: 6-methoxy or 6,7-dimethoxy or [6,7-b]-dioxolo or -dioxano, or c) a quinoxaline with the following substituents: an acylated hydroxymethyl group in both the 2- and 3-position and a methoxy group in both the 6- and 7-position on the benzene ring, or d) a quinoxaline with a methyl group in both the 2- and 3-position and no substituent, or the following substituents, on the benzene ring: methyl, alkoxy, amino, 6-hydroxy, 5,8-dihydroxy or a sulphonic acid group, ascorbic acid being used as the anti-oxidant.

Claim 8

Process according to claim 1, which comprises interposing a washing step after at least one of the following process steps: (1) silver developing, (2) dye bleaching, (3) silver bleaching and (4) silver fixing.

Claim 9

Aqueous treatment bath suitable for carrying out the silver bleaching step (3) of the process according to claim 1, which treatment bath contains (a) a strong acid which produces a pH value of at most 2, (b) a water-soluble iodide in an amount of 2 to 50 g/liter, (c) a water-soluble organic nitro compound in an amount of 1 to 30 g/liter, (d) a diazine compound in an amount of 0.2 to 5 g/liter and (e) an anti-oxidant in an amount of 0.5 to 10 g/liter.