Bleaching bath
AssigneeAgfa-Gevaert
InventorsGustav Tappe, Ralf Wichmann, Heinz Meckl
Life of this patent
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Abstract
A readily biodegradable bleaching bath having an adequate bleaching effect (1) contains an iron(III) complex salt in which at least 20 mol-% and preferably at least 80 mol-% of the complexing agent corresponds to formula (I) ##STR1## in which R.sub.1 is hydrogen or hydroxy, n is 1 or 2, x is 2 or 3 and y is 0 or 1 and the sum of x and y is always 3, and (2) an excess of free complexing agent of 1 to 120 mol-% and preferably 5 to 20 mol-%, based on the iron complex or the iron complex salt, and (3) is adjusted to a pH value of .ltoreq.4.5.
Claims2
A bleaching bath which contains
- (1) an iron(III)-complex salt in which at least 80 mol-% of the complexing agent is nitrilomonopropionodiacetic acid, and
- (2) an excess of free complexing agent of 5 to 20 mol-%, based on the iron complex salt, and
- (3) is adjusted to a pH-value of .ltoreq.4.5, wherein said iron(III)-complex salt is contained in an amount of 0.005 to 0.5 mol/l. of said bath.
A method for bleaching a light sensitive silver halide color photographic material to decrease residual silver which comprises after color developing subjecting the color photographic material to a bath which contains
- (1) an iron(III)-complex salt in which at least 80 mol-% of the complexing agent is nitrilomonopropionodiacetic acid, and
- (2) an excess of free complexing agent of 5 to 20 mol-%, based on the iron complex salt, and
- (3) is adjusted to a pH-value of .ltoreq.4.5, wherein said iron(III)-complex salt is contained in an amount of 0.005 to 0.5 mol/l. of said bath.
Dependencies are inferred from the claim text.