EP1172691A1 - Method of processing photographic silver-dye-bleach materials and bleaching solution preparations therefor - Google Patents

Abstract

In processing exposed and developed photographic silver dye bleach material with aqueous bleach formulation containing acid component (I), silver chelant, bleaching catalyst(s) and optionally antioxidant, water-soluble oxidant and/or bleaching accelerator, (I) consists of 0.1-2.0 mole/l strong inorganic and/or organic sulfonic acid(s) as main component (IA), and 0.5-80 mole-%, with respect to (IA), of different organic sulfonic acid(s) as component (IB). An Independent claim is also included for the aqueous formulations used for processing the exposed and developed material in this way.

Description

Technical field

The invention relates to a new method for processing exposed and developed silver color bleaching materials and suitable for this process Preparations in the form of ready-to-use aqueous solutions or with Water-dilutable concentrates in liquid or solid form.

State of the art

(A) Entwicklung des latenten Silberbildes

(B) Farbbleichung an den metallisches Silber enthaltenden Bildstellen

(C) Silberbleichung zur Umwandlung des Restsilberbildes in komplexe, lösliche Silberverbindungen

(D) Fixierung durch Herauslösung und Entfernung aller im Material enthaltenen Silberverbindungen

Four processing steps are generally required to process silver color bleaching materials:

(A) Development of the latent silver image

(B) Color bleaching at the image areas containing metallic silver

(C) Silver bleaching to convert the residual silver image into complex, soluble silver compounds

(D) Fixation by removing and removing all silver compounds contained in the material

Several processes have been described that shorten this process sequence enable. For example, process steps (B) and (C), (C) and (D) or (B), (C) and (D) can be combined. Most common is the combination of process steps (B) and (C).

Those used for color and / or silver bleaching or combined bleaching The most important ingredients in preparations are strong acid, a complexing agent for the silver and a color bleaching catalyst.

Those used for color and / or silver bleaching or combined bleaching Preparations (baths) are strongly acidic, i.e. H. they have a pH under 2, especially under 1. This pH value is set in the Usually with a single strong acid, primarily a mineral acid like Hydrochloric acid, sulfuric acid, nitric acid, hydrobromic acid, hydroiodic acid, Perchloric acid or phosphoric acid. Furthermore, strong ones organic acids, for example sulfamic acid, substituted sulfamic acid compounds, p-toluenesulfonic acid or other organic sulfonic acids are used become.

The acids can be the bleaching preparations directly as free acids or as adducts can be added with weak bases, as described in patent application EP 0'034'793 has been described.

It is also possible to reduce the processing time by reducing the individual To achieve process steps. In the bleaching step, especially in the combined Color and silver bleaching, the dye is generally bleached much faster than silver bleaching, especially in places that have the highest Contain a lot of metallic silver after the development step. Therefore the bleaching of the metallic silver at these points is generally the rate-determining one Factor that prevents the bleaching step from being shortened.

Many different compounds have been claimed as bleach accelerators, generally quaternary ammonium salts or tertiary amines. In the Patent applications DE 2'139'401, DE 2'651'969, DE 2'716'135 and EP 0'517'989 water-soluble phosphines are claimed as bleach accelerators. The effectiveness this bleach accelerator depends very much on the external conditions from. Furthermore, some of the most effective bleach accelerators are very expensive or difficult to obtain.

In patent EP 0'517'989 it is described that the bleaching rate is controlled by the addition of paradimethylaminopyridine or tetramethylpyrazine is increased. However, this solution has the disadvantage that the substances used are either are toxic or very expensive.

The bleaching baths used today have the disadvantage that the speed bleaching is insufficient. This leads to an undesirably long treatment time at a relatively low temperature or to a high degree of corrosivity, high Evaporation and high oxidation at elevated temperature and reduced treatment time.

Description of the invention

The aim of the present invention is to provide preparations for bleaching photographic silver color bleaching materials that allow the bleaching time respectively. Shorten processing time and / or the bleaching temperature resp. Lower processing temperature.

Another object of the invention is to provide preparations for bleaching photographic silver color bleaching materials that allow it without use of bleaching accelerators the same or shorter bleaching times with the same Temperature in comparison to known preparations containing bleach accelerators to reach.

Another object of the invention is to provide inexpensive preparations without bleach accelerator for bleaching photographic silver color bleaching materials, the other advantages, for example with regard to ecology, toxicity, ecotoxicity, Have solubility, stability and exploitability.

Another object of the invention are concentrates and partial concentrates for Production of ready-to-use aqueous bleaching preparations.

The present invention relates to a method for processing exposed and developed photographic silver color bleaching materials by the exposed and developed material treated with aqueous bleaching preparations becomes.

It has now surprisingly been found that particularly high bleaching speeds for silver color bleaching materials and at the same time cost-effective solutions be obtained when the acid component of the bleaching compositions Mixture of a main acid component with at least one additional acid component is, this additional acid component contains organic sulfonic acids.

The invention is equally suitable for separate color and silver bleach baths as well as for combined color and silver bleach baths.

a) eine Hauptsäurekomponente und eine Zusatzsäurekomponente

b) ein Silberkomplexierungsmittel

c) einen oder mehrere Bleichkatalysatoren

d) gegebenenfalls ein Oxidationsschutzmittel

e) gegebenenfalls ein wasserlösliches Oxidationsmittel

f) gegebenenfalls einen Bleichbeschleuniger.

Contain such bleaching preparations according to the invention

a) a main acid component and an additional acid component

b) a silver complexing agent

c) one or more bleaching catalysts

d) optionally an antioxidant

e) optionally a water-soluble oxidizing agent

f) optionally a bleaching accelerator.

The main acid component is used to adjust the pH value of the bleaching bath to a value <2, preferably <1. Are preferred as the main acid component strong inorganic acids, such as sulfuric acid, phosphoric acid, Hydrohalic acids or perchloric acid, sulfamic acid or substituted Sulfamic acid compounds, or strong organic sulfonic acids such as p-toluenesulfonic acid; or mixtures of these acids.

The purpose of the additive acid component is to increase the bleaching rate. The acids of the additional acid component are organic sulfonic acids, preferred aromatic sulfonic acids. These aromatic sulfonic acids can be monosulfonic acids or be polysulfonic acids, they can be further unsubstituted or be substituted. Preferred substituents are alkyl having 1 to 3 carbon atoms, especially methyl; Halogen such as chlorine, bromine or iodine; Hydroxyl or with Alkyl with 1 to 3 carbon atoms substituted hydroxyl; unsubstituted carboxyl or carboxyl substituted with alkyl having 1 to 3 carbon atoms or Cyan. The acids of the add acid component are different from those the main acid component.

Examples of such organic sulfonic acids are benzenesulfonic acid, p-chlorobenzenesulfonic acid, p-hydroxybenzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, 2-mesitylenesulfonic acid, 2-naphthalenesulfonic acid, 1-naphthalenesulfonic acid, 1-hydroxy-2-naphthalenesulfonic acid, 1-hydroxy-4-naphthalenesulfonic acid, 1,5-naphthalenedisulfonic acid and 1-hydroxy-3,6-naphthalenedisulfonic acid. These acids can as free acids or as their salts, especially inorganic, in the Bleaching preparations are introduced.

The amount of acids in the additional acid component is 0.5 to 80 mole percent the amount of acids of the main acid component, preferably 2 to 50 mole percent from that.

Preferred acids of the additional acid component are p-toluenesulfonic acid, 1-naphthalenesulfonic acid and 2-naphthalenesulfonic acid or mixtures thereof.

A mixture of p-toluenesulfonic acid is particularly preferred as the additional acid component with 2-naphthalenesulfonic acid.

The baths used for color bleaching contain the most important components in addition to the mixture of a main acid component and an additional acid component a complexing agent b) for the silver and one or several color bleaching catalysts c).

The main bleaching catalysts used are diazine compounds such as pyrazine, Quinoxaline or phenazine and their derivatives are used. suitable Bleaching catalysts are described, for example, in patent applications DE 735'672, DE 1'547'720, DE 2'144'297, DE 2'144'298, DE 2'722'776 and DE 2'722'777 Service.

A suitable complexing agent for silver is, for example, thiourea. Favorable results are obtained when a water-soluble iodide is preferred Sodium, potassium or ammonium iodide is used, such as this has been described in US Pat. No. 3,620,744: this makes enrichment more troublesome Prevents silver complexes in the bleaching bath. However, an antioxidant must be used be used that prevents the oxidation of iodide to iodine.

Reductones or water-soluble mercapto compounds are advantageously used as antioxidants d). Suitable reductones are in particular aci-reductones with a 3-carbonylidene (1,2) grouping such as reductin, triose reductone or preferably ascorbic acid. Suitable mercapto compounds are e.g. B. thioglycerol or compounds of the formula HS-C _x H _2x -B, preferably compounds of the formula HS-C _m H _2m -COOH, where x is a number between 2 and 12, B is a sulfonic acid or carboxylic acid group and m is the number 3 or 4 mean. Mercapto compounds that can be used as antioxidants have been described in patent applications DE 2'258'076 and DE 2'423'814. Further suitable antioxidants are alkali metal, alkaline earth metal or ammonium bisulfite adducts of organic carbonyl compounds, preferably alkali metal or ammonium bisulfite adducts of monoaldehydes with 1 to 4 carbon atoms or of dialdehydes with 2 to 5 carbon atoms, as described in the patent application DE 2,737,142. The formaldehyde bisulfite adduct and the corresponding adducts of acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, glyoxal, malondialdehyde and glutardialdehyde are particularly preferred. If appropriate, the tertiary water-soluble phosphines mentioned below as bleach accelerators can also be used simultaneously as antioxidants. Hypophosphoric acid can also be used as an antioxidant, as has been described in GB 630,222.

For bathrooms with which the dye and the image silver are bleached at the same time should be, or also for baths that only serve to bleach silver, is the addition a water-soluble oxidizing agent is necessary; in addition, the concentration of the color bleaching catalyst or the color bleaching catalysts a simple color bleaching bath can be significantly increased, such as has been described in patent application DE 2,448,433.

Water-soluble aromatic mononitro- and dinitro compounds and anhraquinone sulfonic acid derivatives are used. The use of such oxidizing agents serves in addition to the oxidation of the silver also to influence the color balance and to lower the gradation of the images produced in the silver color bleaching process, as in the patent applications DE 735'672, GB 45394190, GB 539'509 and JP 69-22673 has been. The mononitro and dinitro compounds are preferably mono- or dinitrobenzenesulfonic acids, which are alkyl with 1 to 4 carbon atoms, Hydroxyl, amino or halogen (chlorine or bromine) can be substituted. The Sulfonic acids are preferably added in the form of their readily soluble salts. For example, the sodium or potassium salts of o-nitrobenzenesulfonic acid are suitable, the m-nitrobenzenesulfonic acid, the 2,4-dinitrobenzenesulfonic acid, the 3,5-dinitrobenzenesulfonic acid, 3-nitro-4-chlorobenzenesulfonic acid, 2-chloro-5-nitrobenzenesulfonic acid, 4-methyl-3,5-dinitrobenzenesulfonic acid, 3-chloro-2,5-dinitrobenzenesulfonic acid, 2-amino-4-nitrobenzenesulfonic acid, 2-amino-4-nitro-5-methoxybenzenesulfonic acid and 4-nitrophenolsulfonic acid.

These bleach catalysts, if they are nitrated benzenesulfonic acids, increase the bleaching rate when adding large amounts to the bleaching bath strong. But since, as mentioned before, they change the color balance a lot, are they as aromatic sulfonic acids in the sense of our invention in the Practice not useful.

Suitable bleaching accelerators f) are, for example, quaternary ammonium salts, as have been described in patent applications DE 2,139,401 and DE 2,716,135. The quaternary, optionally substituted piperidine, piperazine, pyrazine, quinoline and pyridine compounds are preferred, the latter being particularly preferred. Tetraalkylammonium compounds (alkyl with 1 to 4 carbon atoms) and alkylenediammonium compounds (alkylene with 2 to 6 carbon atoms) are also suitable. Specifically, tetraethylammonium iodide, N-methylpyridinium iodide, N-methylquinolinium iodide, N-hydroxyethylpyridinium chloride, N-hydroxypropylpyridinium bromide, N-methyl-2-hydroxymethylpyridinium iodide, N, N-dimethylpiperinium iodide, N, N'-dimethylpulfonium fluoride ( ₃ ) ₃ N ⁺ (CH ₂ ) ₂ N ⁺ (CH ₃ ) ₃ • 2 I ^- and (CH ₃ ) ₃ N ⁺ (CH ₂ ) ₆ N ⁺ (CH ₃ ) ₃ • 2 I ^- .

Other bleach accelerators are water-soluble tertiary phosphines with at least a cyanoethyl group, as described in patent application DE 2,651,969 have been. The sodium salt of bis- (β-cyanoethyl) -2-sulfoethylphosphine, the sodium salt of bis- (β-cyanoethyl) -3-sulfopropylphosphine, the sodium salt of bis- (β-cyanoethyl) -4-sulfobutylphosphine, the bis (β-cyanoethyl) -2-methoxyethylphosphine, the bis (2-methoyethyl) - (β-cyanoethyl) phosphine, the sodium salt of (β-cyanoethyl) phenyl-3-sulfopropylphosphine, the (β-cyanoethyl) phenyl-2-methoxyethylphosphine and the bis (2-methoxyethyl) phenylphosphine called.

The repetition of individual treatments (each in another tank with a Bath of the same composition as the previous one) is possible, whereby in some cases better use of the bathroom can be achieved. If the number of available tanks and the time schedule allow, So water baths can also be used between baths with different effects be used. It is up to the person skilled in the art to determine the optimal quantity ratio depending on the type of catalysts selected from the sensitometric To determine results.

All baths can contain other additives such as hardening agents, wetting agents, contain optical brighteners or UV protection agents.

Baths of conventional composition can be used to develop silver are, for example, those used as developer hydroquinine or ascorbic acid and optionally additionally 1-phenyl-3-pyrazolidine. Possibly the developing bath already contains a bleaching catalyst.

The silver fixing bath can be composed in a known and customary manner. Sodium thiosulfate or preferably ammonium thiosulfate, for example, serves as the fixing agent, optionally with additives such as sodium bisulfite and / or sodium metabisulfite. The fixing bath can also be combined with the bleaching bath as a so-called Bleach-fix bath available.

a) Säurekomponente: 0.1 bis 2 Mol / l;

b) Silberkomplexierungsmittel: 0.01 bis 1 Mol / l, vorzugsweise 0.05 bis 0.5 Mol / l;

c) mindestens einen Bleichkatalysator: 0.001 bis 0.1 Mol / l;

d) gegebenenfalls ein Oxidationsschutzmittel: 0.01 bis 0.1 Mol / l;

e) gegebenenfalls ein wasserlösliches Oxidationsmittel: 0.001 bis 0.2 Mol / l;

f) gegebenenfalls einen Bleichbeschleuniger: 0.01 bis 0.1 Mol / l.

The aqueous bleaching preparations used generally contain components a) to f) in the following amounts:

a) acid component: 0.1 to 2 mol / l;

b) silver complexing agent: 0.01 to 1 mol / l, preferably 0.05 to 0.5 mol / l;

c) at least one bleaching catalyst: 0.001 to 0.1 mol / l;

d) optionally an antioxidant: 0.01 to 0.1 mol / l;

e) optionally a water-soluble oxidizing agent: 0.001 to 0.2 mol / l;

f) optionally a bleaching accelerator: 0.01 to 0.1 mol / l.

The temperature of the bleaching baths is generally between 20 ° C and 90 ° C, preferably between 20 ° C and 60 ° C, but of course at a higher temperature the required processing time is shorter than at a lower temperature. The Bleach baths are stable within the specified temperature range. In general become the aqueous bleaching preparations required for processing in the form of dilute aqueous solutions containing the components mentioned included, used. However, other methods are also conceivable, for example the application in paste form.

This temperature range also applies to the other processing steps. The aqueous bleaching preparation according to the present invention can for example from solid or liquid, especially aqueous concentrates of individual or all components a) to f) are produced. One uses advantageously for example two liquid concentrates, one of which is the acid mixture a) and the oxidizing agent e) and the other the other components b), c), d) and f) contains, in the latter concentrate to improve solubility, in particular component c) an additional solvent such as ethyl or propyl alcohol, Ethylene glycol monomethyl or ethyl ether can be added. This Concentrates and partial concentrates, which are also the subject of the present invention have excellent stability and are therefore longer Can be stored in time. These concentrates can optionally with water or with a mixture of water and an organic solvent become.

The concentrates of the individual or all components a) to c) and, if appropriate d), e) and f) or their combinations, for example from the components a) and e) and components b), c), d) and f) can be two to twenty times, preferably five to ten times the amount of the individual components included as previously indicated for the ready-to-use bleach baths has been. They are usually in the form of solid, liquid or pasty concentrates in front.

The inventive method for processing exposed and developed Silver color bleaching materials, for example, can be more positive in manufacturing Color images in automatic copying and recording machines or in high-speed processing other silver color bleaching materials can be used.

In the following examples, parts and percentages are by weight, unless otherwise stated.

Experimental information

Photomechrome PMC 794 was used as the silver color bleaching material manufactured by ILFORD Imaging Switzerland GmbH, Marly, Switzerland and is distributed by PMI PLC, Bookham, Great Britain.

Test strips of this material are exposed to 1000 luxs of white light. With such overexposed material, the image whites can be improved and the accelerated bleaching of silver when using the inventive ones Bleaching baths are particularly well demonstrated.

Processing takes place in successive tanks at 30 ° C in 13 successive Tanks, with the first 2 tanks developer, the following 3 tanks Bleaching bath, the next tank of water, the following 3 tanks of fixer and the last 4 tanks contain water.

In a first processing sequence, the residence time per bath is 14 seconds, which results in a total processing time of about 3 minutes.

In a second processing sequence, the dwell time per bath is 21 seconds, which results in a total processing time of about 4½ minutes.

DE-222 from ILFORD Imaging Switzerland GmbH is available.

BL-222, which is available from ILFORD Imaging Switzerland GmbH, was used as the comparative bleaching bath. This bleaching bath has the composition given in Table 1: component Quantity (g / l) water 966.0 sulfuric acid 49.3 Irgasol P 0.1 Sodium salt of 3-mercaptopropyl sulfonic acid 5.2 2,3,6-Trimethylchinoxalin 1.5 potassium iodide 15.0 Sodium salt of m-nitrobenzenesulfonic acid 7.6

P-222 contains about 0.5 mol / l of sulfuric acid. Irgasol P is a wetting agent that is available from Ciba Specialty Chemicals, Basel, Switzerland.

The organic sulfonic acids are added in different amounts to this bleaching bath, whereby bleaching baths according to our invention are obtained. Before the processing process, all bleaching baths are set to the same final weight. A comparison bleaching bath is used in which only the amount of sulfuric acid is increased.
The exposed material samples as described above are processed and then the amount of silver Ag _res (mg / m ² ) still present in the material and the minimum visual density D _{vis are} determined by X-ray analysis. In practice, processing is carried out at temperatures higher than 30 ° C. In practice, images with a minimum visual density D _vis > 0.15 are unusable, since such visual density is perceived as extremely disruptive in the image whites. Under the experimental conditions described here, images with a minimum visual density> 0.40 are considered unusable.

Examples example 1

Addition of p-toluenesulfonic acid (Table 2): Added acid (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 81 00:57 136 0.66 0.0515 38 00:41 90 00:59 0.1340 <5 00:15 41 00:41 0.2164 <5 00:09 9 00:27 0.2988 <5 00:07 <5 00:09 0.4019 <5 00:07 <5 00:08

The results in Table 2 clearly show that when p-toluenesulfonic acid is added, the minimum visual density D _vis decreases very sharply with both processing times and a useful image is thus obtained even with short processing times. The residual silver Ag _res is completely removed in both processing times.

Example 2

Addition of the sodium salt of p-toluenesulfonic acid (Table 3): Added salt (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 00:58 0.64 0.1340 00:17 00:41 0.2164 00:10 00:23

The results in Table 3 clearly show that when the sodium salt of p-toluenesulfonic acid, about the same results are obtained as with the addition equal molar amounts of free acid.

Example 3

Addition of the sodium salt of xylene sulfonic acid (mixture of isomers) (Table 4): Added salt (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 75 00:54 95 0.60 0.0183 55 00:48 67 00:53 0.0456 26 00:33 50 00:47 0.0913 <5 00:18 21 00:33 0.1825 <5 00:08 <5 00:11

The results in Table 4 clearly show that when the sodium salt of the isomer mixture of xylene sulfonic acid is added, the minimum visual density D _vis decreases very sharply with both processing times and a useful image is thus obtained even with short processing times. The residual silver Ag _res is completely removed in both processing times.

Example 4

Addition of mesitylenesulfonic acid (Table 5): Added acid (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 91 00:57 130 0.67 0.0166 49 00:45 111 0.63 0.0332 23 00:36 83 00:56 0.0498 10 00:23 63 00:50

The results in Table 5 clearly show that when mesitylenesulfonic acid is added, the minimum visual density D _vis decreases very sharply with both processing times and a useful image is thus obtained even with short processing times. The amount of residual silver Ag _res is greatly reduced in both processing times.

Example 5

Addition of 2-naphthalenesulfonic acid (Table 6): Added acid (mol / I) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 73 00:55 117 0.65 0.0072 40 00:43 93 0.60 0.0144 10 00:25 45 00:48 0.0216 <5 00:11 9 00:26 0.0288 <5 00:08 <5 00:10 0.0360 <5 00:08 <5 00:09

The results in Table 6 clearly show that when 2-naphthalenesulfonic acid is added, the minimum visual density D _vis decreases very sharply in both processing times and a useful image is thus obtained even with short processing times. The residual silver Ag _res is completely removed in both processing times.

Example 6

Addition of the sodium salt of 2-naphthalenesulfonic acid (Table 7): Added salt (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 59 00:50 119 0.66 0.0078 15 00:26 77 00:53 0.0156 <5 00:10 12 00:28 0.0235 <5 00:08 <5 00:09 0.0313 <5 00:07 <5 00:08

The results in Table 7 clearly show that when the sodium salt is added, the 2-naphthalenesulfonic acid can be obtained about the same results as for Add equal molar amounts of free acid.

Example 7

Addition of the sodium salt of 1-naphthalenesulfonic acid (Table 8): Added salt (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 76 00:54 101 0.60 0.0139 <5 00:19 20 00:53 0.0208 <5 00:09 <5 00:09 0.0278 <5 00:08 <5 00:08

The results in Table 8 clearly show that when the sodium salt of 1-naphthalenesulfonic acid is added, the minimum visual density D _vis decreases very sharply in both processing times and a useful image is thus obtained even with short processing times. The residual silver Ag _res is completely removed in both processing times.

Example 8

Addition of 1-hydroxy-4-naphthalenesulfonic acid (Table 9): Added acid (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 77 00:56 114 0.66 0.0076 56 00:50 90 0.62 0.0190 43 00:44 70 00:55 0.0381 25 00:36 50 00:50

The results in Table 9 clearly show that the addition of 1-hydroxy-4-naphhainesulfonic acid reduces the minimum visual density D _vis at both processing times.

Example 9

Addition of the disodium salt of 1-hydroxy-3,6-naphthalenedisulfonic acid (Table 10): Added salt (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 89 00:56 126 0.66 0.0230 63 00:52 89 0.60 0.0575 42 00:45 66 00:54 0.1149 9 00:25 20 00:36

The results in Table 10 clearly show that when the disodium salt of 1-hydroxy-3,6-naphthalenedisulfonic acid is added, the minimum visual density D _vis decreases very sharply with both processing times and a useful image is thus obtained even with short processing times.

Example 10

Addition of p-chlorobenzenesulfonic acid (Table 11): Added acid (mol / I) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 00:51 0.60 0.0960 00:11 00:29

The results in Table 11 clearly show that when p-chlorobenzenesulfonic acid is added, the minimum visual density D _vis decreases very sharply in both processing times and a useful image is thus obtained even with short processing times.

Example 11

Add a mixture of p-toluenesulfonic acid and the sodium salt of 2-naphthalenesulfonic acid (Table 12): Added acid (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 75 00:56 92 0.60 a 17 00:29 31 00:38 b 5 00:16 14 00:30 c <5 00:08 <5 00:11 a: 0.0824 mol / l p-toluenesulfonic acid b: 0.0824 mol / l p-toluenesulfonic acid and 0.0078 mol / l of the sodium salt of 2-naphthalenesulfonic acid c: 0.0824 mol / l p-toluenesulfonic acid and 0.0156 mol / l of the sodium salt of 2-naphthalenesulfonic acid

The results in Table 12 clearly show that when p-toluenesulfonic acid and the sodium salt of 2-naphthalenesulfonic acid are added together, the minimum visual density D _vis decreases very sharply with both processing times and a useful image is thus obtained even with short processing times. The residual silver Ag _res is completely removed in both processing times.

Comparative example

Addition of sulfuric acid (Table 13): Added acid (mol / l) Processing time 4½ minutes Processing time 3 minutes Ag _res D _vis Ag _res D _vis 0.0000 71 00:52 94 0.60 0.1367 92 00:59 0.3054 47 00:47 76 00:58 0.6122 36 00:44 55 00:54

The results in Table 13 show that even when large amounts of sulfuric acid are added, the minimum visual density D _vis decreases only slightly with both processing times, but also that under these conditions, no usable image is obtained with both processing times. The residual amount of silver Ag _res is reduced to about half of the original value, which is insufficient.

As the comparison of Examples 1 to 11 shows with the comparative example, the Increasing the amount of sulfuric acid in the bleaching bath alone does not increase the Bleaching rate, but only the addition of the aromatic according to the invention Sulfonic acids.

Claims (11)

A method of processing exposed and developed photographic silver color bleaching materials by treating the exposed and developed material with aqueous bleaching preparations which a) an acid component b) a silver complexing agent c) one or more bleaching catalysts d) optionally an antioxidant e) optionally a water-soluble oxidizing agent f) optionally a bleaching accelerator contain, characterized in that the acid component consists of a main acid component in an amount of 0.1 to 2.0 mol / l and an additional acid component in an amount of 0.5 to 80 mol percent based on the main acid component, wherein the main acid component consists of strong inorganic acids or strong organic sulfonic acids or their mixtures and the additional acid component is composed of organic sulfonic acids or mixtures thereof and the additional acid component does not contain the same acids as the main acid component. A process for processing exposed and developed photographic silver color bleaching materials according to claim 1, characterized in that the additional acid component consists of unsubstituted or substituted aromatic sulfonic acids or mixtures thereof. A method for processing exposed and developed photographic silver color bleaching materials according to claim 2, characterized in that the substituents of the aromatic sulfonic acids from the group consisting of alkyl having 1 to 3 carbon atoms; Halogen; Hydroxyl or hydroxyl substituted with alkyl of 1 to 3 carbon atoms; Carboxyl or carboxyl or cyan substituted with alkyl having 1 to 3 carbon atoms. A process for processing exposed and developed photographic silver color bleaching materials according to claim 2, characterized in that as aromatic sulfonic acids benzenesulfonic acid, p-chlorobenzenesulfonic acid, p-hydroxybenzenesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, 2-mesitylenesulfonic acid, 2-naphthalenesulfonic acid, 1-naphthalenesulfonic acid, 1- Hydroxy-2-naphthalenesulfonic acid, 1-hydroxy-4-naphthalenesulfonic acid, 1,5-naphthalenedisulfonic acid, 1-hydroxy-3,6-naphthalenedisulfonic acid or mixtures thereof can be used. A process for processing exposed and developed photographic silver color bleaching materials according to claim 4, characterized in that p-toluenesulfonic acid, 1-naphthalenesulfonic acid or 2-naphthalenesulfonic acid or mixtures thereof are used as aromatic sulfonic acids. A process for processing exposed and developed photographic silver color bleaching materials according to claim 4, characterized in that a mixture of p-toluenesulfonic acid with 2-naphthalenesulfonic acid is used as the aromatic sulfonic acids. A process for processing exposed and developed photographic silver color bleaching materials according to claim 1, characterized in that the main acid component consists of sulfuric acid and the additional acid component consists of p-toluenesulfonic acid, 1-naphthalenesulfonic acid or 2-naphthalenesulfonic acid or mixtures thereof. A process for processing exposed and developed photographic silver color bleaching materials according to claim 7, characterized in that the additional acid component consists of a mixture of p-toluenesulfonic acid and 2-naphthalenesulfonic acid. A process for processing exposed and developed photographic silver color bleaching materials according to claim 7, characterized in that the additional acid component consists of a mixture of p-toluenesulfonic acid and 2-naphthalenesulfonic acid. Aqueous preparations for processing exposed and developed photographic silver color bleaching materials according to any one of the claims 1 to 9. Aqueous preparations for processing exposed and developed photographic silver color bleaching materials according to one of claims 1 to 9, characterized in that they are color or silver bleaching baths or combined color and silver bleaching baths.