GB2214322A

GB2214322A - A photographic colour developer

Info

Publication number: GB2214322A
Application number: GB8900872A
Authority: GB
Inventors: Helmut Haseler; Gustav Tappe
Original assignee: Agfa Gevaert AG
Current assignee: Agfa Gevaert AG
Priority date: 1988-01-20
Filing date: 1989-01-16
Publication date: 1989-08-31
Anticipated expiration: 2009-01-16
Also published as: DE3801536A1; GB8900872D0; JPH023040A; GB2214322B

Description

1 1 1 2214322 A PHOTOGRAPHIC COLOUR DEVELOPER 1 This invention relates to

a photographic colour developer which is particularly suitable for the development of photographic materials of high silver chloride content.

The formation of colour photographic images by imagewise coupling of the developer oxidation product with coupler molecules is well known. Cyan, magenta and yellow partial images are normally produced, the final dye image being built up from them. The developers are generally primary aromatic amino compounds which are reacted at the exposed silver halide areas to form the developer oxidation product.

Suitable silver halides are silver bromide, silver bromide iodide, silver chloride, silver chloride bromide and silver chloriode bromide iodide, silver halide emulsions of high chl-oride content or pure silver chloride emulsions being used to an increasing extent for colour negative paper because these high- chloride emulsions show a number of favourable properties. Thus, their reduced natural sensitivity to visible light may be used to produce materials with no yellow filter layers which are essential for example in highly sensitive materials, such as negative films or reversal films. In addition, the use of high-chloride silver halide emulsions provides for much shorter development times because the chloride ions released during development have a less inhibiting effect than bromide ions.

However, the advantage of this rapid development can only be optimally utilized if the developer oxidation product formed in accordance with the silver reduction can be completely reacted with the coupler to the image dye. However, this reaction is adversely affected by standard oxidation inhibitors which are supposed to prevent oxidation of the developer substance, because part of the developer oxidation product formed is reduced in competition with the A-G 5324 1 1 1 1 colour coupling reaction and is.thus lost to that reaction if, for example, sulfite, hydroxylamine, ascorbic acid or hydroxyurea is used as the oxidation inhibitor.

It has now been found that the coupling reaction takes place without any loss of colour density in a bromidefree fast developer if a hydroxyketone or 1,3-diketone is used in an effective quantity as antioxidant. These substances are distinguished by high anti- oxidation activity.

Accordingly, the present invention relates to a devel- oper composition for the development of colour photographic materials, more especially colour photographic materials of high silver chloride content, which is substantially free from bromide and contains at least one primary aromatic amino developer in an effective quantity and at least one compound corresponding to formulae (I) and (II) R 2 R,-C- (CH 1 2) n-CO-R3 0H R,-CH-C-CH -C-CH-R 11 2 11 1 - 1 2 0 0 R 2 (I) (II) in which 1 and R 2 represent hydrogen or C 1-C 4 alkyl, 3 represents C 1- C 4 alkyl or hydroxymethyl or R 1 and R 3 together represent the remaining members of a 5or 6-membered cycloaliphatic ring and n is 0 or 1, in an effective quantity.

Suitable hydroxyketones are, for example, hydroxyAcetone, 1,3-dihydroxyacetone and its dimer, 3-hydroxy-2-butanone, 4-hydroxy-2-butanone, 2-hydroxycyclopentanone and 2-hydroxy cyclohexanone. Hydroxyacetone is preferred. Suitable 1,3 diketones are, for example, 2,4-pentanedione and 2,4-hexane7 dione. In general, approximately 100 mg to 30 g/1 of the hydroxyketone or 1,3-diketone are used in the developer.

A-G 5324 1 1 Hydroxyketones are preferred.

Particularly suitable primary aromatic amino developers are pphenylenediamines and, in particular, N,N-dialkyl-pphenylenediamines, in which the alkyl groups and the aromatic nucleus are substituted or unsubstituted. Examples of such compounds are N,N-diethyl-pphenylenediamine hydrochloride, 4-N,N-diethyl-2-methylphenylenediamine hydrochloride, 4-(Nethyl-N-2-methanesulfonylaminoethyl)-2methylphenylenediamine sesquisulfate monohydrate, 4-(N-ethyl-N-2hydroxyethyl)-2- methylphenylenediamine sulfate and 4-N,N-diethyl-2, 21methanesulfonylaminoethyl phenylenediamine hydrochloride.

The colour developer preferably contains complexing agents in an effective quantity for complexing iron ions and complexing agents in an effective quantity for complexing calcium ions, although both functions may even be performed by a single substance. The developer is particularly suitable for rapid processing with a development time of, for example, 45 seconds, development being followed by bleaching and subsequent fixing or by combined bleaching and fixing and then washing or stabilization. The developer may contain benzyl alcohol although it may also be free from benzyl alcohol.

As already mentioned, the colour developer according to the invention is substantially free from bromide. This means that it may contain bromide ions in a concentration that is sensitometrically ineffectual. This quantity of bromide ions is not added to the fresh developer, instead it may dissolve out from the material to be developed during the development process. it should be limited to less than 30 30 mg/1. The colour developer according to the invention preferably contains chloride ions, more especially in a quantity of from 1 to 5 g/1. Suitable complexing agents for complexing calcium ions are, for example, aminopolycarboxylic acids which are well A-G 5324.

1 1 known per se. Typical examples of such aminopolycarboxylic acids are nitrilotriacetic acid, ethylenediamine tetraacetic acid (EDTA), 1,3diamino-2-hydroxypropyltetraacetic acid, Aiethylenetriamine pentaacetic acid, N,NI-bis-(2-hydroxy- benzyl)-ethylenediamine-N,N'-diacetic acid, hydroxyethyl ethylenediamine triacetic acid, cyclohexanediaminotetraacetic acid and aminomalonic acid.

Other calcium complexing agents are polyphosphates, phosphonic acids, aminopolyphosphonic acids and hydrolyzed polymaleic anhydride, for example sodium hexametaphosphate, 1- hydroxyethane-1,1-diphosphonic acid, amino-tris-methylenephosphonic acid, ethylenediamine tetramethylenephosphonic acid. 1-Hydroxyethane-1,1- diphosphonic acid also acts as an iron complexing agent.

Special iron complexing agents are, for exAmple, 4,5dihydroxy-1,3benzenedisulfonic acid, 5,6-dihydroxy-1,2,4benzenetrisulfonic acid and 3, 4,5-trihydroxybenzoic acid.

For complexing calcium, approximately 0.2 to approxi-mately 1.8 mol of a calcium complexing agent is preferably used per mol developer substance.

The iron complexing agent is used in quantities of approximately 0.02 to approximately 0.2 mol per mol developer substance.

The developer according to the invention is, in part- icular, an aqueous alkaline solution having a pH value above 7 and more especially in the range from 9 to 13. This pH value is adjusted with buffers known per se, such as alkali carbonates and alkali phosphates.

The developer according to the invention may contain small quantities of sulfite to afford further protection against oxidation. However, the sulfite content is preferably from 0 to 0.2 mol/mol developer substance.

A colour developer according to the invention has the following composition for example:

water 800 ml A-G 5324 1 1 4,5-dihydroxy-1,3-benzenedisuifonic acid EDTA potassium sulfite isononyl phenoxy polyglycidol hydroxy acetone colour developer CD 3 potassium chloride potassium carbonate 0.5 g 2 9 0.2 9 2 2 5 2 30 9 M1 9 9 9 make up with water to 1 liter pH 10.1 Another advantage of the antioxidants according to the invention lies in the preparation of only two partial concentrates which, diluted with water, form the ready-touse solution.

Where the antioxidants according to the invention are used, the hitherto standard three partial concentrates (one for the antioxidant, the second for the developer and the third for the alkali) may be reduced to two partial concentrates, namely: one part for the developer and the antioxidant and the second part for the alkali. This measure reduces packaging costs and provides for easier handling.

A formulation such as this is not possible, for example, where N,Ndialkyl hydroxylamines are used as the antioxidant in accordance with WO 87/04534 without drastic reductions in quality. According to this publication, dialkyl hydroxylamines are recommended as antioxidants for bromide-free developer compositions which are said to be suitable for the development of high-chloride silver halide emulsions.

Another disadvantage of a two-component formulati.on using dialkyl hydroxylamine is the poor stability in storage because the solution containing dialkyl hydroxylamine and the developer is brown- black in colour after storage for 12 days at 5VC and hence unuseable while a similar solution containing hydroxyacetone is only slightly coloured and fully useable.

A-G 5324 -1 1 Although a two-part formulation is also described in DE-OS 29 10 251, high stability in storage is only achieved in this case if the partial concentrate containing developer and antioxidant contains at least 95% by weight organic solvents, for example glycols. This leads to an unfavourably high concentration of around 50 mI organic solvent per liter in-use solution.

If, by contrast, a developer- and antioxidant-containing concentrate is prepared using a compound according to the in- vention, for example hydroxyacetone, there is little, if any, need to add organic solvents without any reduction in storability.

Accordingly, the concentrate according to the invention of developer compound and antioxidant may contain 50 to 100% by weight water as solvent. Glycols may be used as organic solvent components (0 to 50% by weight). The quantity of antioxidant in the concentrate is 5 to 50% by weight and preferably 10 to 30% by weight while the quantity-of antioxidant is from 5 to 50% by weight and preferably from 10 to 30% by weight. The pE value is in the range from 1.0 to 3.0. The second part of the formulation is a standard aqueous alkali solution in which, if desired, up to 50% by weight of the water may be replaced by an organic solvent, for example a glycol.

COMPARISON EXAMPLE Comparison concentrate containing diethyl hydroxylamine as oxidation inhibitor in the developer"containing partial concentrate: Partial concentrate A water 4,5-dihydroxy-1,3-benzenedisulfonic acid isononyl phenoxypolyglycidol potassium sulfite sulfuric acid, 20% by weight diethyl hydroxylamine, 85% by weight A-G 5324 M1 0.5 g 0.5 g 0.2 g 3 ml 3 ml 1 colour developer CD3 5 g make up with water to 25 ml The alkali part has the following composition:

Partial concentrate B water EDTA potassium sulfite potassium chloride potassium carbonate ml 2 g 0.1 g 2 9 9 make up with water to 50 ml.

Preparation of the ready-to-use developer solution, 1 liter:

water 925 ml partial concentrate A 25 ml partial concentrate B 50 ml pH 10.1 The bleaching/fixing bath has the following composition water 800 ml ammonium - iron - EDTA EDTA sodium disulfite 58 9 9 9 ammonium thiosulfate 70 9 adjust with acetic acid to pH 5.5, make up with water to 1 liter.

EXAMPLE

Hydroxyacetone as oxidation inhibitor in the developercontaining partial concentrate:

The developer partial concentrates are prepared as in the Comparison Example, except that the 3 ml diethyl hydroxylamine in partial concentrate A is replaced in'accor- dance with the invention by 2 ml hydroxyacetone.

The developer partial concentrates of the Comparison Example and Example are stored for 12 days at 500C in sealed polyethylene bottles.

The bleaching/fixing bath has the same composition as in the Comparison Example.

A-G 5324 Photographic testing is carried out using colour paper containing silver chloride by comparison with developers from frethly prepared partial concentrates.

Processing conditions:

Bath Residence time Temperature colour developer 45 secs. 35C bleaching/fixing bath rinsing drying secs 90 secs.

C 30 C The sensitometric data are shown in the following Tables.

A-G 5324.

, 1 Table 1

Sensitometric data of Comparison Example a) developer from freshly prepared partial concentrates b) developer from partial concentrate stored under heat 1 D min Sensitivity Gamma 1 Gamma 2 D max at density 0.6 blue green red blue green red blue green red blue green red blue green red a) 0.15 0.11 0.10 1.54 1.51 1.51 1.70 1.70 1.62 3.25 3.40 3.10 2.72 2.67 2.61 b) 0.16 0.12 0.11 1.61 1.60 1.71 1.70 1.80 2.42 3.02 2.80 1.90 2.69 2.64 2.56 z Gamma 1 is the threshold gradation Gamma 2 is the shoulder gradation Table 2

Sensitometric data of the Example a) developer from freshly prepared partial concentrates b) developer from partial concentrates stored under heat D min blue green red a) 0.15.0.12 0.11 b) 0.17 0.14 0.12 is X> Sensitivity at density 0.6 blue green red 1.56 1.52 1.53 1.59 1.54 1.55 Contrast Gamma 1' blue green red 1.70 1.70 1.66 1.80 1.70 1.61 Contrast Gamma 2 blue green red 3.40 3.70 3.20 3.30 3.53 3.00 D max blue green red 2.70 2.68 2.63 2.66 2.64 2.59 0 9 1 The Tables show that the sensitometric deviations of the developer from partial concentrate containing the comparison substance diethyl hydroxylamine lead to unuseable results after storage under heat.

By contrast, the sensitometric data of the developer from partial concentrate according to the invention containing hydroxyacetone change only slightly after storage under heat.

A-G 5324.

1

Claims

CLAIMS 1. A photographic colour developer which is substantially free from

bromide and contains at least one primary aromatic amino developer in an effective quantity and at least one compound corresponding to formulae (I) and (II)

R 12 R -C-(CH) -CO-R 1 1 2 n 3 OH R,-CH-C-CH -C-CH-R 1 1 2 U A 1 kII 2 0 0 R 2 (1) (11) in which 1 and R 2 represent hydrogen or C 1-C 4 alkyl, 3 represents C l- C 4 alkyl or hydroxymethyl or R 1 and R 3 together represent the remaining members of a 5or 6-membered cycloaliphatic ring and n is 0 or 1, in an effective quantity.
2. A photographic colour developer as claimed in claim 1 consisting of two partial concentrates of which one contains a colour developer and antioxidant while the other contains alkali.
3. A photographic colour developer substantially as herein described with reference to the Examples.

A-G 5324.

Published 1989 at The Patent Office, State House, 68,71 High Holborn. London WClR 4TP. Further copiesmaybe obtained from The PatentOffize.

Scaeo Bran-?mL, St Crs. 0,'Dingon.Xeia WW:',PJ)- 11rinted by Multiplex tachniques ltd. St Mary Cray, Kent, Con- 1/87