Photographic silver halide colour materials

Abstract: A colour photographic element comprising at least one colour-forming unit sensitive to a particular region of the spectrum comprising a silver halide emulsion layer and, in or adjacent said layer, (1) a development inhibitor releasing developer (IRD) which comprises a hydrazide, sulphonamidophenol, sulphonamidonaphthol, or hydroquinone moiety attached directly or via a linking group to a development inhibitor moiety which compound is oxidisable during silver halide development enabling release of the development inhibitor moiety under alkaline conditions, (2) a sulphonhydrazide colour developing agent, and (3) a colour coupler capable of forming image dye with the sulphonhydrazide during silver halide development.

Description: The present invention relates to photographic silver halide colour materials and to processes for the formation of photographic colour images. Existing commercial photographic silver halide colour materials form dye images by the reaction of oxidised p -phenylenediamine colour developers with a colour coupler. The colour developing solutions employed contain the colour developing agent and used developer solutions need to be disposed of safely. Attempts have been made to incorporate p -phenylene-diamine colour developing agents into silver halide photographic materials but these have had little success largely due to the pronounced staining produced. The use of aryl and heterocyclic sulphonhydrazides as colour developers in aqueous colour developer solutions which form an azo dye on coupling with a colour coupler are described in US Patent 2 424 256, and copending British application 9125688.3 respectively. It is well known in conventional p -phenylene-diamine colour forming chemistry to release a group from the coupling position (usually called a Coupling Off Group or COG) which has a photographic effect, eg development inhibition. By the release of such a compound one colour layer can affect the image formation in an adjacent colour layer. Such an effect is not available to sulphonhydrazide image forming chemistry as shown by the following scheme: The leuco dye is essentially colourless and the COG cannot leave to form a dye. US Patent 4 108 663 describes the use of inhibitor releasing sulphonamido-phenol developers (IRDs) in conventional p-phenylene-diamine colour forming chemistry. European Patent 0 242 685 describes hydrazide compounds that release photographically useful fragments during silver halide development. JP-A-064546 discloses the incorporation of a compound including a timing group into a photographic layer which does not contain the silver halide to improve sharpness and/or graininess of an image. WO-A-83/00939 describes the formation of an azo or azo-methine dye by developing the photographic material with a heterocyclic substituted hydrazide as colour developing agent. The present invention employs compounds which are capable of releasing a development inhibitor in systems where the colour developer is a sulphonhydrazide. According to the present invention there is provided a colour photographic element comprising at least one colour-forming unit sensitive to a particular region of the spectrum comprising a silver halide emulsion layer and, in or adjacent said layer, (1) a development inhibitor releasing developer (IRD) which comprises a hydrazide, sulphonamidophenol, sulphonamidonaphthol, or hydroquinone moiety attached directly or via a linking group to a development inhibitor moiety which compound is oxidisable during silver halide development enabling release of the development inhibitor moiety under alkaline conditions, (2) a sulphonhydrazide colour developing agent, and (3) a colour coupler capable of forming image dye with the sulphonhydrazide during silver halide development. In a preferred embodiment development takes place in the presence of an electron transfer agent (ETA). Preferably, the alkaline solution contains ETA, for example a pyrazolidinone. A specific ETA that may be used is 4-hydroxymethyl-4-methyl-1-phenylpyrazolidin-3-one. The IRD preferably has the formula: RED-(LINK) n -INHIB (1) wherein RED is a hydrazide, sulphonamidophenol, sulphonamidonaphthol, or hydroquinone moiety oxidisable during photographic colour development leading to the release of INHIB or LINK-INHIB by means of alkaline hydrolysis, β-elimination, intramolecular nucleophilic displacement or an addition-elimination reaction, INHIB is a heterocyclic photographic development inhibitor moiety, LINK is a group attached to a heteroatom of INHIB and is capable, in an alkaline environment, of releasing INHIB from LINK-INHIB, and n is 0 or 1. In one embodiment the IRD, the colour coupler and the sulphonhydrazide colour developer are incorporated into the photographic element in droplets of a high boiling coupler solvent. It is especially preferred to codisperse the IRD, the coupler and the developer in the same droplet. The RED group may have one of the formulae: R-NHNHCO- , R-CONHNH- , or wherein R is a substituted or unsubstituted alkyl, alkenyl or aryl group, R', R'' or R''' are each H or a substituted or unsubstituted alkyl, alkenyl or aryl group, or together with the carbon atoms to which they are attached, R' and R'' complete a ring, and wherein at least one of R, R', R'' or R''' is a ballast group. The group LINK may be: where m is 1 or 2, R 5 is H, -NHSO 2 R, -NHCOR, or halogen, and R 6 is an alkyl group, or, together with RED, LINK forms part of the ring: The INHIB moiety may be derivable from any of the heterocyclic development inhibitors referred to in Research Disclosure Item 308119, Section F, December 1989 published by Kenneth Mason Publications, Emsworth, Hants, United Kingdom. Examples are moeities derived from tetrazoline thiols, eg 1-phenyl-5-mercaptotetrazole, thiadiazoline thiol or benzotriazole. Examples of IRD compounds according to the present invention are: In addition to the compounds illustrated above other compounds which may be used are described in European Patent 4 242 685. The present compounds form dye and release a photographically useful compound as follows: The IRD, coupler and sulphonhydrazide developing agent are associated with a silver halide emulsion layer coated on a support to form the photographic element. As used herein, the term "associated with" signifies that the compound is incorporated in the silver halide emulsion layer or in a layer adjacent thereto where, during processing, it is capable of reacting with silver halide development products. The photographic elements can be single colour elements or multicolour elements. Multicolour elements contain dye image-forming units sensitive to each of the three primary regions of the spectrum. Each unit can be comprised of a single emulsion layer or of multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art. A typical multicolour photographic element comprises a support bearing yellow, magenta and cyan dye image-forming units comprising at least one blue-, green- or red-sensitive silver halide emulsion layer having associated therewith at least one yellow, magenta or cyan azo dye-forming coupler respectively. The element can contain additional layers, such as filter and barrier layers. In the following discussion of suitable materials for use in the emulsions used or useful in the elements of this invention, reference will be made to Research Disclosure, December 1978, Item 17643, published by Industrial Opportunities Ltd., The Old Harbourmaster's, 8 North Street, Emsworth, Hants P010 7DD, U.K. This publication will be identified hereafter as "Research Disclosure". The silver halide emulsion employed in the elements of this invention can be either negative- working or positive-working. Suitable emulsions and their preparation are described in Research Disclosure Sections I and II and the publications cited therein. Suitable vehicles for the emulsion layers and other layers of elements of this invention are described in Research Disclosure Section IX and the publications cited therein. The photographic elements of this invention or individual layers thereof, can contain brighteners (see Research Disclosure Section V), antifoggants and stabilisers (see Research Disclosure Section VI), antistain agents and image dye stabiliser (see Research Disclosure Section VII, paragraphs I and J), light absorbing and scattering materials (see Research Disclosure Section VIII), hardeners (see Research Disclosure Section XI), plasticisers and lubricants (see Research Disclosure Section XII), antistatic agents (see Research Disclosure Section XIII), matting agents (see Research Disclosure Section XVI) and development modifiers (see Research Disclosure Section XXI). The photographic elements can comprise a variety of supports as described in Research Disclosure Section XVII and the references described therein. The photographic elements can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image. Preferred sulphonhydrazide colour developing agents have the formula: R-NHNH-SO 2 -R 1 (2) wherein R is a heterocyclic group which may be substituted, and R 1 is an alkyl, aryl or heterocyclic group, either of which may be substituted, and wherein R or R 1 contains a ballasting group of such size and configuration as to render the compound non-diffusible. When the ballast group is in group R, the diazo compound formed on development is unable to diffuse and a water-soluble sulphinato compound is formed which washes out of the photographic element. When, however, the ballast group is part of R 1 , a mobile diazonium compound is formed while the sulphinate compound is ballasted and remains in the material. The high boiling solvent which may be used to incorporate the IRD, colour developer and colour coupler in the photographic element may be any solvent already known as a coupler solvent (and used for incorporating couplers into photographic elements). Many such solvents are listed in Research Disclosure Item 308119, December 1989 published by Kenneth Mason Publications, Emsworth, Hants, United Kingdom. The colour developer may be incorporated in the same or different droplets of coupler solvent used for the couplers themselves. When the ballast group is in group R, it is preferred to co-disperse both coupler and colour developing agent and IRD in the same droplet of coupler solvent. The heterocyclic sulphonhydrazide developing agents may have one of the following general formulae: R 2 is alkyl or substituted alkyl, or a substituted or unsubstituted aromatic heterocyclic group, R 3 is H, alkyl, aryl, alkoxy, Cl, F, or, especially, an electron-withdrawing group such as CF 3 , COMe, CONH 2 , COOAlkyl CN, SO 2 R, SO 2 NHR, and R 4 is H or a general organic substituent. In all the above examples, the developer may be ballasted through a suitable group present in R 2 and/or the substituents R 3 and R 4 on the heterocyclic ring. Examples of sulphonhydrazides are: With negative-working silver halide emulsions the processing leads to a negative image. To obtain a positive (or reversal) image, this step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but not form dye, and then uniform fogging of the element to render unexposed silver halide developable. Alternatively, a direct positive emulsion can be employed to obtain a positive image. Development is preferably followed by the conventional steps of bleaching, fixing, or bleach-fixing, to remove silver and silver halide, washing and drying. A 1 minute post-process base dip (pH 10.4 solution - Na 2 CO 3 26.5 g/l and NaHCO 3 6.3g/l) is required to obtain the azo-dye in its full-coloured anionic form for magenta and cyan dyes. The following Examples are included for a better understanding of the invention. EXAMPLE 1 Dispersions Co-dispersions of IRD (1) of the formula and the conventional image coupler of the formula: and the sulphonhydrazide developing agent of the formula: are prepared by the following method. The three coupler dispersions used contained w/w 6.0% gelatin, 8.8% coupler (Y1), 1 molar equivalent of developing agent (D3), 0.15, 0.10 or zero molar equivalents of IRD(1) respectively, and coupler solvents in the ratio coupler:tricresyl phosphate:2-(2-butoxyethoxy)ethyl acetate 1:0.5:1.5. The dispersions were washed for 6 hours at 4°C. Coatings The coupler/developer/IRD dispersions were coated with a green sensitised silver bromoiodide emulsion in the following format: Gel supercoat Gelatin 1.5 gm -2 Emulsion Layer Silver bromoiodide 1.60 gm -2 Coupler (+dev+IRD) 1.04 mmol -2 Gelatin 2.42 gm -2 Bis(vinylsulphonyl)-methane(hardener) 0.06 gm -2 Support Cellulose acetate The coatings were slit and chopped into 30 cm x 35 mm strips and exposed (0.1 sec, DLV+WR9 filters) and processed through the following sequence using an activator solution of the given composition. Processing Sequence Activator 2.5 min Wash 1.0 min Bleach 4.0 min Wash 2.0 min Fix 4.0 min Wash 2.0 min Activator Solution Na 2 CO 3 26.5 g/l NaHCO 3 6.3 Na 2 SO 3 2.0 NaBr 1.0 4-hydroxymethyl-4-methyl-1-phenylpyrazolidin-3-one 0.2 pH = 10.4 The maximum density and contrast obtained from the resulting anionic yellow dye are shown in Table 1 below. & IRD (1) D max Contrast (γ) 0 1.48 1.24 10 1.15 1.04 15 0.94 0.76 The data demonstrate that development inhibitor is released from IRD (1).

Claims: A colour photographic element comprising at least one colour-forming unit sensitive to a particular region of the spectrum comprising a silver halide emulsion layer and, in or adjacent said layer, (1) a development inhibitor releasing developer (IRD) which comprises a hydrazide, sulphonamidophenol, sulphonamidonaphthol, or hydroquinone moiety attached directly or via a linking group to a development inhibitor moiety which compound is oxidisable during silver halide development enabling release of the development inhibitor moiety under alkaline conditions, (2) a sulphonhydrazide colour developing agent, and (3) a colour coupler capable of forming image dye with the sulphonhydrazide during silver halide development. A colour photographic element as claimed in claim 1 in which the IRD has the general formula: RED-(LINK) n -INHIB (1) wherein RED is a hydrazide, sulphonamidophenol, sulphonamidonaphthol, or hydroquinone moiety oxidisable during photographic colour development leading to the release of INHIB or LINK-INHIB by means of alkaline hydrolysis, β-elimination, intramolecular nucleophilic displacement or an addition-elimination reaction, INHIB is a heterocyclic photographic development inhibitor moiety, LINK is a group attached to a heteroatom of INHIB and is capable, in an alkaline environment, of releasing INHIB from LINK-INHIB, and n is 0 or 1. A colour photographic element as claimed in claim 2 in which the group RED has one of the formulae: R - NHNHCO- , R - CONHNH - , or wherein R is a substituted or unsubstituted alkyl, alkenyl or aryl group, R', R'' or R''' are each H or a substituted or unsubstituted alkyl, alkenyl or aryl group, or together with the carbon atoms to which they are attached, R' and R'' complete a ring, and wherein at least one of R, R', R'' or R''' is a ballast group. A colour photographic element as claimed in claim 2 or 3 in which the group LINK is: where m is 1 or 2, R 5 is H, -NHSO 2 R, -NHCOR, or halogen, and R 6 is an alkyl group, or, together with RED, LINK forms part of the ring: A colour photographic element as claimed in any of claims 2 to 4 in which the INHIB moiety is derived from a tetrazoline thiol, a benzotriazole or a thiadiazoline thiol. A colour photographic element as claimed in any of claims 1 to 5 in which the IRD is one of the following compounds: A colour photographic element as claimed in any of claims 1 to 6 in which the IRD, the colour coupler and the sulphonhydrazide colour developer are incorporated into the photographic element in droplets of a high boiling coupler solvent. A colour photographic element as claimed in claim 7 in which the IRD, the colour coupler and the sulphonhydrazide colour developing agent are codispersed in the same droplet. A colour photographic element as claimed in any of claims 1 to 8 in which the material is a multicolour photographic material comprising a support bearing a yellow dye image-forming unit comprised of at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow azo dye-forming coupler, at least one magenta dye image-forming unit comprising at least one green-sensitive silver halide emulsion layer having associated therewith at least one magenta azo dye-forming coupler at least one cyan dye image-forming unit comprising at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan azo dye-forming coupler.

Inventors: STANLEY PAUL LOUIS REGINALD, TSOI SIU CHUNG, STANLEY, PAUL LOUIS REGINALD, TSOI, SIU CHUNG
Applicants: EASTMAN KODAK CO, KODAK LTD, EASTMAN KODAK COMPANY, KODAK LIMITED
Application year: 1993
Main classification: G03C7
IPC codes: G03C7, G03C1