Developer liquid for high contrast development

Abstract: A developer liquid suited for use in development of photographic silver halide emulsion layer materials which liquid contains : 1) hydroquinone or a substituted hydroquinone as sole developing agent or said hydroquinone as main developing agent in combination with an auxiliary developing agent in an amount less than 10 mole % with respect to the main developing agent, 2) an inorganic compound yielding free sulphite ions in an amount of at least 5 grams per litre, 3) an organic anti-fogging agent corresponding to the following general formula (Z) : wherein : X² represents an alkyl group or an aryl group including said groups in substituted form or an amino group including said group in substituted form; the amount of anti-fogging agent being in the range of 50 mg to 1 g per litre, 4) a polymer containing a plurality of alkylene oxide units, and 5) the necessary alkaline material to have in said liquid a pH of at least 10.5.

Description: 1. Field of the Invention This invention relates to a method of effecting high contrast development of an image-wise exposed photographic silver halide emulsion layer material and development liquid used therefor. 2. Background of the Invention In the reproduction of continuous tone information for mechanical printing purposes, it is customary to make a half-tone photographic intermediate, usually a film negative, in which the gradations in tone are represented by dots of differing size. The quality of the resulting halftone picture is closely connected with the shape, spectral density, and uniformity of the dots of the half-tone print. In order to obtain very high-contrast screen dots in halftone images it has been practice to formulate developers, so-called lith-developers, containing essentially a p-dihydroxybenzene such as hydroquinone, an alkali, an alkali metal bromide and a low level of free sulphite ions. Very high contrast results, preferably with gamma above 10, also called "lith-gradation", can be obtained with said high-contrast developers and so-called "lith silver halide emulsion materials". In these materials the silver halide comprises at least 50 mole % of chloride, the balance, if any, being bromide and optionally a minor amount of iodide. Hydroquinone developers having a low sulphite ion concentration are commonly referred to as "lith-type developers" and their mechanism of operation is described by J.A.C. Yule in the Journal of the Franklin Institute, 239 (1945), pages 221 to 230. In conventional "lith" developers the low sulfite ion concentration is inadequate to provide effective protection against aerial oxidation. As a result, a conventional "lith" developer is lacking in stability and tends to give erratic results depending on the length of time that it has been exposed to air. As explained e.g. in US-P 4,081,280 it is necessary when using a lith-developer with low free sulphite content to replenish carefully the developer solution compensating : (1) for developer exhaustion by aerial oxidation, and (2) for use of developer in function of the treated exposed photographic material. According to US-P 3,972,719 in order to be less dependent on replenishment for aerial oxidation a high contrast developer with relatively high sulphite content and an anti-fogging nitro-compound is provided. Said developer contains not more than 0.05 g/litre of any auxiliary developing agent that shows a superadditive developing effect with a p-dihydroxybenzene developing agent and may contain a polymer containing a plurality of alkylene oxide units, i.e. a polymeric oxyalkylene compound, for controlling the development speed. According to FR-A-2239704 the development of black-and-white photographic silver halide emulsion materials proceeds in the presence of 1-phenyl-5-mercapto-tetrazole compounds wherein the phenyl group is subsituted with the group -NH-COR-or -NH-SO₂R, wherein R is an aliphatic group containing 3 to 10 carbon atoms. Said mercapto-tetrazole compound reduces the contamination of the equipment during development in which the pH of the developer is monitored preferably between 8.5 and 10.5. EP-A-358 165 relates to a method of developing a silver halide photographic material with a developer containing at least one compound selected from the group consisting of compounds represented by Formulae I, II and III, wherein Formulae III corresponds to the following structure : wherein M represents a hydrogen atom, alkali metal atom or -NH₄; X represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an aryl group. an alkoxy group, a carbamoyl group, a sulfamoyl group, an acylaminogroup or a sulfoamido group. Said compounds are intended for use as stabilizers of the photosensitive material in which fogging and lowering of sensitivity may occur during the preparation, storage or at the time of processing which according to the Examples proceeds with a developer having a pH of 10.4. According to published European Patent Application 0 196 705 a method of effecting high contrast development of an imagewise exposed photographic silver halide emulsion layer material proceeds in an aqueous medium having a pH of 10 to 12 containing : a) (i) hydroquinone or a substituted hydroquinone, (ii) an auxiliary developing agent having a developing activity of such degree as to give when utilized in the Standard Development test defined in the specification a relative development rate f x in the range of about 1-2, b) free sulphite ions in an amount of at least 5 g per litre, and c) an organic anti-fogging agent corresponding to one of the following general formulae (A) and (B) : wherein : Y¹ is a nitro-substituent in the 5- or 6-position of the indazole nucleus, X¹ is hydrogen or a sulphonic acid group in salt form, R is hydrogen or a lower (C₁-C₅) alkyl group, X is a substituent being or containing a carboxyl group or sulphonic acid group in salt form, d) a polymer containing a plurality of alkylene oxide units and having a molecular weight of at least 1500, and said ingredients a) to d) being present in the aqueous developing medium in such relative amounts that development therein of the exposed photographic material carrying a latent continuous tone wedge image under the same development conditions given the density versus log exposure sensitometric curve of the resulting silver wedge would have a) a maximum gradient (γ) of at least 5.0 between the log exposure values measured at densities of 0.3 and 3.0 above fog on the log exposure scale and b) a gradient (γ v ) of at least 2.0 in the toe between the log exposure values measured at densities of 0.1 and 0.6 above fog on the log exposure scale. Up till recently the characteristic of lith-development resulting in particularly high gradation necessary for sharp screen dot reproduction was restricted to the use of silver halide emulsion layers the silver halide of which was mainly silver chloride. According to US-P 4,710,451 a method of effecting high contrast development of an image-wise exposed photographic silver halide emulsion layer material is provided, wherein an image-wise exposed silver halide emulsion material the silver halide of which is at least 90 mole percent silver bromide, the remainder if any, being chloride and/or iodide is developed in a developing medium containing hydroquinone as sole developing agent, a large amount of sulphite (at least 5 g per litre of free sulphite ions), a nitro-indazole as anti-fogging agent, a polyoxyethylene polymer having a molecular weight of at least 1500 and an inorganic alkaline compound to impart to the developing medium a pH of at least 10.5. Since the nitro-indazole and other indazoles such as cyano- and halo-indazoles, particularly 5-cyano and 5-chloro-indazole are instable in alkaline medium and loose their anti-fogging activity and development retarding activity the developer formulation is kept in concentrated form in two parts before use and combined and diluted to the desired strength with water, the nitro-indazole antifogging agent(s) and polyoxyalkylene polymer being kept before use in acid medium in one part and the other ingredients in alkaline medium in the other part. Although by said procedure the stability problem is solved it would be more convenient to dispose of a single liquid high contrast developer that does not suffer from degradation on storage and use. 3. Summary of the Invention It is an object of the present invention to provide a method of high contrast development of an imagewise exposed silver halide emulsion layer with a developer liquid containing an anti-fogging agent that has a good stability in alkaline aqueous medium. It is a further object of the present invention to provide an aqueous alkaline liquid for high gradation development of an imagewise exposed photographic silver halide emulsion material wherein said liquid contains an anti-fogging agent having a good stability against alkali. Other objects and advantages of the present invention will appear from the further description and examples. According to the present invention a developer liquid suited for use in the development of photographic silver halide emulsion layer materials contains : 1) hydroquinone or a substituted hydroquinone as sole developing agent or said hydroquinone as main developing agent in combination with an auxiliary developing agent in an amount less than 10 mole % with respect to the main developing agent, 2) an inorganic compound yielding free sulphite ions in an amount of at least 5 grams per litre, 3) an organic anti-fogging agent corresponding to the following general formula (Z) : wherein : X² represents an alkyl group or an aryl group including said groups in substituted form or an amino group including said group in substituted form; the amount of anti-fogging agent being in the range of 50 mg to 1 g per litre, 4) a polymer containing a plurality of alkylene oxide units, and 5) the necessary alkaline material to have in said liquid a pH of at least 10.5, preferably between 10.8 and 11.8. Further the present invention provides a method for high contrast development of an image-wise exposed photographic silver halide emulsion layer material, the development being carried out by contacting the photo-exposed photographic material with an aqueous alkaline developer liquid, having a pH of at least 10.5, preferably having a pH in the range of 10.8 to 11.8, and containing ingredients 1) to 4) as follows : 1) hydroquinone or a substituted hydroquinone as sole developing agent or said hydroquinone as main developing agent in combination with an auxiliary developing agent in an amount less than 10 mole % with respect to the main developing agent, 2) an inorganic sulfite compound providing free sulfite ions in an amount of at least 5 grams per litre, 3) an organic anti-fogging agent corresponding to the following general formula (Z) : wherein : X² represents an alkyl group or an aryl group including said groups in substituted form or an amino group including said group in substituted form, and 4) a polymer containing a plurality of alkylene oxide units and having a molecular weight of at least 1500, said ingredients 1), 2), 3) and 4) being present during said development in said aqueous medium in such amounts that when said photographic material is image-wise exposed through a continuous tone wedge and test developed in the thus constituted aqueous developing medium for a time of 45 s at 30 °C and fixed there results a silver wedge image corresponding with a log exposure versus density sensitometric curve wherein the maximum gradient (γ) is at least 5 and the product of said maximum gradient (γ) and of the gradient in the toe (γv) of said curve is at least 20; the maximum gradient is measured between the log exposure values corresponding with the densities 0.3 and 3.0 above fog of said curve and the gradient in the toe is measured between the log exposure values corresponding with the densities 0.1 and 0.6 above fog of said curve. Still further the present invention provides a method for high contrast development of an image-wise exposed photographic silver halide emulsion layer material, wherein in said photographic material before its development already in the manufacturing stage has been incorporated an auxiliary developing agent, and the method comprises the step of contacting said photographic material with an alkaline aqueous liquid having a pH of at least 10.5 and containing ingredients 1) to 4) as defined hereinbefore; the amount of the auxiliary developing agent in the photographic material being less than 10 mole % with respect to ingredient 1). 4. Detailed description of the Invention Hydroquinone compounds that are used according to the present invention as main developing agents include unsubstituted hydroquinone and e.g. the following substituted hydroquinones : chlorohydroquinone, bromohydroquinone, isopropylhydroquinone, toluhydroquinone, methylhydroquinone, 2,3-dichlorohydroquinone, 2,5-dimethylhydroquinone, 2,3-dibromohydroquinone, 1,4-dihydroxy-2-acetophenone-2,5-dimethylhydroquinone, 2,5-diethylhydroquinone, 2,5-di-p-phenethylhydroquinone, 2,5-dibenzoylaminohydroquinone, or 2,5-diacetaminohydroquinone and mixtures thereof. The preparation of these hydroquinone compounds is known to those skilled in the art. Auxiliary developing agents suited for use according to the present invention are e.g. p-amino-phenol, p-methylaminophenol, p-phenylene diamine sulphate, N,N-diethyl-p-phenylene diamine hydrochloride or a 1-phenyl-3-pyrazolidinone type developing agent including the possibility of using a mixture of at least two of them. Preferred auxiliary developing agents are p-methylaminophenol and 1-phenyl-3-pyrazolidinone type developing agents, e.g. 1-p-carboxyphenyl-4,4-dimethyl-3-pyrazolidinone. Preference is given likewise to an auxiliary developing agent within the scope of the main claim of US-P 4,756,990 corresponding with EP 0196705. The coverage of the auxiliary developing agent in the photographic material is e.g. in the range of 0.1 to 5 g/m². When applied in the developer liquid the developing agent(s) is (are) preferably used in a concentration in the range of 10 to 60 g/l. The sulphite ions (ingredient 2) are incorporated into the developer composition starting preferably from an alkali metal hydrogen bisulphite or metabisulphite or a corresponding ammonium salt. The concentration of free sulphite ion is preferably in the range of 15 to 80 grams per litre. Preferred representatives of the above defined anti-fogging compounds according to general formula (Z) are given with their structural formula and melting point (°C) in the following Table 1. The synthesis of said compounds is illustrated by the detailed preparation of compound No. 2 of Table 1. Preparation of compound No. 2 Preparation of 1-(3-aminophenyl)-5-(4-acetoxybenzylthio)-tetrazole Intermediate Compound A 2.84 g (0.022 mole) of diisopropylethylamine were added slowly at 20 °C to a stirred suspension of 3.86 g (0.02 mole) of 1-(m-aminophenyl)-5-mercaptotetrazole (prepared as described in GB-P 2,088,849) in 20 ml of acetonitrile. Thereupon 3.6 g (0.02 mole) of p-acetoxybenzylchloride [prepared as described in J. Org. Chem. 43 , 1197, (1978)] were added. The resulting reaction mixture was stirred for 3 h at room temperature. Then 50 ml of water were added. The precipitate was filtered with suction, rinsed with water and dried at 50 °C. Yield of compound A : 6.5 g. Melting point : 149.6 °C. Preparation of 1-(3-benzenesulfonamido-phenyl)-5-(4-acetoxybenzylthio)-tetrazole. Intermediate Compound B 388.3 g (2.2 mole) of benzenesulfonylchloride was added at 20 °C to a stirred suspension of 682 g (2 mole) of intermediate compound A and 147 g (2.2 mole) of pyridine in 4 litre of acetonitrile. The reaction mixture was stirred for 5 h at room temperature. Thereupon the mixture was poured in 20 litre of water whereto 250 ml of 12 N hydrochloric acid were added. The precipitate was filtered with suction, washed with water and dried. Yield of compound B : 955 g. Melting point : 132.6 °C. Preparation of 1-[3-(benzenesulfonamido)-phenyl]-5-mercaptotetrazole. Compound No. 2 of Table 1 913.9 g (1.9 mole) of intermediate compound B was added to a solution of 375.5 g (5.7 mole) of potassium hydroxide (85 % wt) in 4.75 litre of methanol. The obtained solution was stirred for 3 h at room temperature. 9.5 litre of water were added to the rection mixture and the pH was adjusted to 6. The slightly turbid solution was washed with methylene chloride. The pH of the aqueous supernatant layer was then lowered to zero with 5N hydrochloric acid. The formed precipitate was filtered with suction, rinsed with water and dried. Yield 573 g; Melting point : 155.5 °C. In the developer liquid the concentration of anti-fogging agents according to said general formula (Z) is preferably up to 1000 mg per litre. Suitable polyalkylene oxide polymers also called polymeric oxyalkylene compounds for use according to the present invention are polyalkyleneoxides as such, e.g. polyethylene oxides of a molecular weight above 1500 or condensation products thereof with e.g. alcohols, glycols, phosphoric acids, sulphonic acids, aliphatic amines and diamines. Examples of condensation products containing oxyalkylene units are described e.g. in European Patent 0196705, the United Kingdom Patent Specifications 600,058 filed January 10, 1946 by E.I. du Pont de Nemours, 871,801 filed November 30, 1956 by Kodak, 920,637 filed May 7, 1959, 940,051 filed November 1, 1961, 945,340 filed October 23, 1961, 949,643 filed November 2, 1961, all four by Gevaert Photo-Producten N.V., 991,608 filed June 14, 1961 by Kodak, 1,015,023 filed December 24, 1962, 1,091,705 filed May 20, 1965, both by Gevaert Photo-Producten N.V., 1,107,022 filed October 7, 1965, 1,147,817 filed August 19, 1966, 1,162,135 filed October 11, 1965 and 1,184,434 filed August 30, 1966 all four by Gevaert-Agfa N.V., in the published German Patent Applications 1,141,531 filed January 24, 1962 by Perutz Photowerke G.m.b.H., 1,188,439 filed May 16, 1964 by Fuji Shashin Film Kabushiki Kaisha, and in the United States Patent Specifications 1,970,578 of Conrad Schoeller and Max Wittwer, issued August 21, 1934, 2,240,472 of Donald R. Swan, issued April 29, 1941, 2,423,549 of Ralph K. Blake, William Alexander Stanton, Ferdinand Schulze, issued July 8, 1947, and 2,441,389 of Ralph K. Blake, issued May 11, 1948. Preferred polyoxyalkylene compounds for use in the present development process are polymers containing an average number of at least 30 repeating oxyethylene units. Particularly good results are obtained with polyoxyethylene compounds having an average number of 70 repeating oxyethylene units. Particularly suited polyoxyethylene polymers for use according to the present invention are disclosed in US-P 3,947,273 of Pollet et al., issued March 30, 1976. These polymers contain end-groups improving the water-solubility. An example of a preferred polyoxyethylene polymer having ionic end groups corresponds to the following structural formula : ⁺X.⁻O-SO₂-(CH₂-CH₂-O) n -CH₂-CH₂-SO₂-O⁻.X⁺, wherein n is e.g. 30 to 200, and X⁺ is a cation, e.g. sodium ion. In the developer liquid the polyoxyalkylene compounds are used e.g. in a concentration up to 2500 mg per litre. Other adjuvants well known to those skilled in the art of developer formulation may be added to the developer liquid used according to the present invention. A survey of conventional developer addenda is given by Grant Haist in "Modern Photographic Processing" - John Wiley and Sons - New York (1979) p. 220-274. Such addenda are e.g. restrainers, such as the soluble halides, e.g. applied as potassium bromide, organic solvents improving the solubility of developing agents, organic anti-foggants, preservatives, e.g. biocides and puffering agents, e.g. carbonates, phosphates and borates. The developer liquid used according to the present invention may contain free bromide ions the concentration of which is preferably in the range of 0.5 to 15.0 g per litre of developer solution. Organic solvent(s) for improving the dissolution of hydroquinone in aqueous medium are described e.g. in US-P 4,030,920, GB-P 1,343,718 and FR-P 71.41095 (publication No. 2,114,785). Solvents for said purpose are watermiscible solvents of the class of amides, alcohols, organic diol compounds and half-ethers thereof. Preferred watermiscible solvents are dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidinone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, and 3-methoxy-2-propanol. These solvents may be present in an amount in the range of 5 to 250 g per litre of the developer liquid. Further is mentioned polyvinylpyrrolidone acting as adsorbent for hydroquinone. The developer formulation may be prepared in a concentrated form and diluted to a working strength just prior to use. Concentrated solutions for automatic processing are widely used in processing machines operating with a replenishment system. Developer solutions used according to the present invention can be left in a machine processor for several weeks without marked degradation. The replenishment proceeds simply by adding a fresh amount of developer after discarding an exhausted portion. The silver halide in the silver halide emulsions used according to the present invention may be any type of photosensitive silver halide. The crystal form of the silver halide grains in the photographic emulsion may be regular (such as cubic or octahedral) or irregular (such as spherical or plate-like or a composite of these forms. The silver halide emulsion may comprise mixed grains of different size and crystal form. The interior and the surface layer of the silver halide grains may be different or the grains may be uniform throughout. Two or more of separately prepared silver halide emulsions may be mixed and coated to form a single silver halide emulsion layer. A preferred silver halide is of the type containing mainly silver chloride, e.g. contains at least 70 mole percent (more preferably at least 90 mole %) of silver chloride. Another preferred type of silver halide is silver bromide-(iodide) the silver halide of which contains no more than 10 mole % of iodide, more preferably not more than 6 mole % of iodide. The silver halide coverage may be equivalent with a coverage of silver in the range of 1.5 to 6 g/m², preferably in the range of 2 to 4 g of silver per m². The silver halide grain size is preferably in the range of 0.05 to 1 µm. A silver halide emulsion material suitable for processing according to the present invention may be sensitized chemically according to any of the well-known techniques in emulsion making, e.g. by digesting with naturally active gelatin or various sulphur, selenium, tellurium compounds and/or gold compounds. The chemical sensitization may proceed not only with the sulfur compounds present inherently in photochemically active gelatin but likewise with thiosulfates, sulfites, thioureas, thiazoles or rhodanines. Reduction sensitization can be carried out with stannous salts, amines, formamidinesulfinic acid, silane compounds, e.g. methyldichlorosilane, hydrazine derivatives, aminoboranes, thiourea dioxide, etc. Specifically contemplated is the combined use of several of the preceding chemical ripening techniques, in particular, gold-sulfur combinations are highly preferred. The silver halide emulsion for use in the present invention may undergo likewise formation or physical ripening of the silver halide grains in the presence of a cadmium salt, a lead salt, a thallium salt, a rhodium salt or a complex salt thereof, an iridium salt or complex salt thereof or mixture of said salts and/or complexes. A silver halide emulsion material suitable for processing according to the present invention may be sensitized spectrally, e.g. is ortho-sensitized or pan- and/or infrared-sensitized, with known spectral sensitizing dyes. For instance, the silver halide can be sensitized spectrally by treatment with a solution of a sensitizing dye in an organic solvent. Spectral sensitizers that may be used are e.g. the cyanines, merocyanines, complex (trinuclear) cyanines, complex (trinuclear) merocyanines, styryls, and hemicyanines. These sensitizing dyes may be used individually or as a combination thereof. A combination of sensitizing dyes is frequently used for super dye sensitization. A silver halide emulsion material to be processed according to the present invention may also contain conventional addenda such as, plasticizers, surface active agents for assisting coating, antistatic agents, agents improving dispersibility, agents preventing sticking of the coated layer, fog-inhibiting compounds other than the already mentioned compound of general formula (Z), such as the mercapto derivatives of benzoxazole, benzthiazole, benzimidazole, benztriazole or tetrazole, particularly 1-phenyl-5-mercaptotetrazole and azaindene compounds, particularly 4-hydroxy substituted (1,3,3a,7)-tetraazaindenes. Further the silver halide emulsion material may contain hardeners, e.g. aldehyde hardeners such as formaldehyde, mucochloric acid, glutardialdehyde and maleic dialdehyde, aziridines, oxypolysaccharides, dimethylurea, hydroxychlorotriazine, divinyl sulphones as described e.g. in US-P 3,841,872, triacrylformal and/or N-carbamoylpyridinium sulfobetain compounds described in US-P 3 880 665, 4 063 952 and published JP-A (Kokai) 89-119477/16. The silver halide emulsions may contain any of the hydrophilic water-permeable binding materials known for that purpose. Suitable materials include gelatin, colloidal albumin, polyvinyl compounds, cellulose derivatives, acrylamide polymers etc. Mixtures of these binding agents may be used. The binding agents for the emulsion layer of the high contrast photographic element may also contain dispersed polymerized vinyl compounds. Such compounds are disclosed in e.g. the United States Patent Specifications 3,142,568 of Robert William Nottorf, issued July 28, 1964, 3,193,386 of Clayton F.A. White, issued July 6, 1965, 3,062,674 of Robert Wong, issued November 6, 1962, 3,220,844 of Robert C. Houck, Donald A.Smith and Joseph S. Yudelson, issued November 30, 1965. They include the water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates, copolymers of alkyl acrylates with acrylic acids, acryloyl-oxyalkyl sulphonic acids, acetoacetoxy alkyl acrylates such as 2-acetoacetoxyethyl methacrylate and the like. These compounds may be incorporated likewise into a layer separate from the silver halide emulsion layer of the photographic element. The vinyl polymers are generally employed in concentrations of about 20 to about 80 %, most often in concentrations of at least 30 % by weight based on the weight of the total binder content. Silver halide emulsions wherein the binder partly consists of poly-N-vinylpyrrolidinone as described in US-P 3,617,284 provide particularly high gradation results. The silver halide emulsion layer(s) processed according to the present invention may be coated on a wide variety of supports. If desired, hydrophilic colloid layers are coated on one or both sides of the support. Typical supports are cellulose nitrate film, cellulose ester film, polyvinyl acetal film, polystyrene film, poly(ethylene terephthalate) film, and related films or resinous materials, as well as glass, paper, metal and the like. Supports such as paper, which are coated with alpha-olefin polymers, particularly polymers of alpha-olefins containing two or more carbon atoms, as exemplified by polyethylene polypropylene, ethylene-butene copolymers and the like may be employed likewise. In processing photographic elements according to the present invention, the time and temperature employed for development can be varied widely. Typically, the development temperature will be in the range of from about 20° C to about 50° C, while the development time in rapid access normally lasts no longer than 90 s. The following examples illustrate the invention without however limiting it thereto. All ratios, percentages and amounts are by weight unless otherwise stated. EXAMPLE 1 (comparative example) A cubic grain type silver iodo-bromide (1 mole % of iodide) emulsion having an average grain size of 0.3 µm, chemically sensitized with ammonium gold(III) thiocyanate and sodium thiosulphate and stabilized with 4-hydroxy-6-methyl-(1,3,3a,7)-tetraazaindene was coated onto a subbed polyethylene terephthalate support at a gelatin coverage of 2.7 g per sq.m. and a coverage of silver halide equivalent with 3.2 g of silver per sq.m. The emulsion layer contained polyethyl acrylate latex and 5-nitro-indazole in amounts corresponding with 2 g/m² and 8 mg/m² respectively. The silver halide emulsion layer was coated with a protective layer containing 0.6 g/m² of gelatin hardened with 1-(4-morfolinocarbamoyl)-4-(2-sulfoethyl)pyridinium hydroxide inner salt. Separate area of the photographic material were exposed in a vertical process camera REPROMASTER RPS 2001 (trade name) through respectively a continuous tone wedge having a constant 0.15 and a grey negative screen for use in screen sensitometry having a screen ruling of 54 lines per cm. The development proceeded by dipping the exposed photographic material into a tray for 45 s at a temperature of 30 °C (i.e. rapid access procedure) using a developer having the following composition : To said composition 100 mg/litre of an antifogging compound (AFC) used according to the present invention and identified by number in Table 1 given hereinbefore is added as indicated in Table 2 furtheron, wherein test 6 relates to the use of 5-nitro-indazole as prior art anti-fogging agent No. X. The freshly prepared developer compositions are used in the development giving the sensitometric results presented in said Table 2. The fixing proceeded for 3 min at 25 °C in a tray using a fixing bath having the following composition : In said Table 2 the photographic speed is expressed in relative sensitivity values (rel. S) measured at density 3.0 above fog. The speed obtained with the developer containing 100 mg/l of compound No. 1 of Table 1 is arbitrarily given the value 100. Gradient values in the toe (γ v ) of the sensitometric curve were measured between the log exposure values at densities 0.1 and 0.6 above fog on the log exposure scale of the sensitometric curve. Straight-line gradient (maximum gradient) values (γ), were measured between the log exposure values at densities 0.3 and 3.0 above fog on the log exposure scale of the sensitometric curve. The screen dot quality was assessed and the rating expressed by numbers, wherein increasing numbers stand for degrading quality. Number 0 stands for developed screen dots having high optical density and sharp, non-indented edges. The other numbers relate to screen dots having gradually reduced optical density and dot edges with increasing indentation and fuzzy structure. Larger than rating value 3 the quality is considered to be no longer commercially acceptable. In order to check the stability of the above developer compositions of tests No. 1-6, these compositions were kept for 4 weeks at 60 °C in a closed plastic bottle. After said treatment the compositions were used again in the development of the photographic material as defined above and the sensitometric results were noticed and listed in Table 3 hereinafter. The relative speed value (rel. S), the gradient value in the toe (γ v ), the straight-line gradient (maximum gradient) value (γ) and dot quality were measured as defined above. From these gradient and dot quality results can be learned that the antifogging compounds AFC 1-5 have a remarkable stabilizing effect, whereas the classical 5-nitro-indazole of test 6' fails in that respect. EXAMPLE 2 A fine grain (average grain size : 0.3 µm) silver chloro-bromide emulsion comprising 16 mole % of bromide was coated onto a subbed polyethylene terephthalate support at a gelatin coverage of 3.6 g per sq.m. and a coverage of silver halide equivalent with 4.1 g of silver. The silver halide was chemically sensitized with gold(III) chloride and sodium thiosulfate and spectrally sensitized to blue 400 to 500 nm) light. The silver halide emulsion layer was covered with a protective layer containing 0.9 g/m² of gelatin hardened with formaldehyde and containing 0.25 g/m² of hydroquinone. The thus obtained photographic material was exposed and developed as defined above in Example 1 using compound No. 2. The sensitometric results (rel. S, γ v , γ and dot quality were practically the same for the development with fresh and artificially aged (heat-treated) developer. EXAMPLE 3 The photographic material of Example 1 was exposed and developed as defined in said Example 1 with the proviso that only compound No. 2 was used as anti-fogging agent and for comparative test purposes 0.50 mmole/liter of an auxiliary developing agent (AD1, AD2, AD3 or AD4) as identified in the following Table 4 was added to the developer composition of Example 1. The use of an auxiliary developing agent is in favour of a shorter developing time and rapid access to the image. The relative speed value (rel. S), the gradient value in the toe (γ v ), the straight-line gradient (maximum gradient) value (γ) and dot quality were measured as defined above and are mentioned in relationship with the applied auxiliary developing agent in Table 4. AD1 is p-amino-phenol AD2 is 1-p-carboxyphenyl-4,4 dimethyl-3-pyrazolidinone AD3 is p-phenylene diamine sulphate AD4 is N,N-diethyl-p-phenylene diamine hydrochloride. From these results can be learned that the identified auxiliary developing agents in the defined minor amount with respect to the principal developing agent (hydroquinone) and anti-fogging agent are useful for graphic art quality development.

Claims: A developer liquid suited for use in development of photographic silver halide emulsion layer materials which liquid contains : 1) hydroquinone or a substituted hydroquinone as sole developing agent or said hydroquinone as main developing agent in combination with an auxiliary developing agent in an amount less than 10 mole % with respect to the main developing agent, 2) an inorganic compound yielding free sulphite ions in an amount of at least 5 grams per litre, 3) an organic anti-fogging agent corresponding to the following general formula (Z) : wherein : X² represents an alkyl group or an aryl group including said groups in substituted form or an amino group including said group in substituted form; the amount of anti-fogging agent being in the range of 50 mg to 1 g per litre, 4) a polymer containing a plurality of alkylene oxide units, and 5) the necessary alkaline material to have in said liquid a pH of at least 10.5. A developer liquid according to claim 1, wherein the sulphite ions are present stemming from an alkali metal hydrogen bisulphite or metabisulphite or a corresponding ammonium salt. A developer liquid according to claim 1 or 2, wherein said liquid contains free sulphite ions in a concentration in the range of 15 to 80 grams per litre. A developer liquid according to any of claims 1 to 3, wherein in said anti-fogging compounds X² is methyl, phenyl, p-tolyl or p-nitro-phenyl. A developer liquid according to any of claims 1 to 4, wherein said polyoxyalkylene compounds are present in a concentration up to 2500 mg per litre. A developer liquid according to any of claims 1 to 5, wherein said liquid contains free bromide ions in the range of 0.5 to 15.0 g per litre of developer liquid. A developer liquid according to any of claims 1 to 6, wherein said liquid contains organic solvent(s) for improving the dissolution of hydroquinone in aqueous medium. A developer liquid according to claim 7, wherein said organic solvent is a watermiscible organic solvent selected from the group consisting of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidinone, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, and 3-methoxy-2-propanol. A developer liquid according to any of claims 7 or 8, wherein said organic solvent(s) are present in an amount in the range of 5 to 250 g per litre of the developer liquid. A developer liquid according to any of the claims 1 to 9, wherein the auxiliary developing agent is p-amino-phenol, p-methylaminophenol, p-phenylene diamine sulphate, N,N-diethyl-p-phenylene diamine hydrochloride or a 1-phenyl-3-pyrazolidinone type developing agent or the developer liquid contains a mixture of at least two of them. A developer liquid according to claim 10, wherein said auxiliary developing agent is 1-p-carboxyphenyl-4,4-dimethyl-3-pyrazolidinone. A method for high contrast development of an image-wise exposed photographic silver halide emulsion layer material, wherein the development is carried out by contacting the photo-exposed photographic material with an aqueous alkaline developer liquid, having a pH of at least 10.5 and containing ingredients 1) to 4) as follows : 1) hydroquinone or a substituted hydroquinone as sole developing agent or said hydroquinone as main developing agent in combination with an auxiliary developing agent in an amount less than 10 mole % with respect to the main developing agent, 2) an inorganic sulfite compound providing free sulfite ions in an amount of at least 5 grams per litre, 3) an organic anti-fogging agent corresponding to the following general formula (Z) : wherein : X² represents an alkyl group or an aryl group including said groups in substituted form or an amino group including said group in substituted form, and 4) polymer containing a plurality of alkylene oxide units and having a molecular weight of at least 1500, said ingredients 1), 2), 3) and 4) being present during said development in said aqueous medium in such amounts that when said photographic material is image-wise exposed through a continuous tone wedge and test developed in the thus constituted aqueous developing medium for a time of 45 s at 30 °C and fixed there results a silver wedge image corresponding with a log exposure versus density sensitometric curve wherein the maximum gradient (γ) is at least 5 and the product of said maximum gradient (γ) and of the gradient in the toe (γv) of said curve is at least 20; the maximum gradient is measured between the log exposure values corresponding with the densities 0.3 and 3.0 above fog of said curve and the gradient in the toe is measured between the log exposure values corresponding with the densities 0.1 and 0.6 above fog of said curve. A method for high contrast development of an image-wise exposed photographic silver halide emulsion layer material, wherein in said photographic material before its development already in the manufacturing stage has been incorporated an auxiliary developing agent, and the method comprises the step of contacting said photographic material with an alkaline aqueous liquid having a pH of at least 10.5 and containing ingredients 1) to 4) as follows : 1) hydroquinone or a substituted hydroquinone as sole developing agent, 2) an inorganic sulfite compound providing free sulfite ions in an amount of at least 5 grams per liter, 3) an organic anti-fogging agent corresponding to the following general formula (Z) : wherein : X² represents an alkyl group or an aryl group including said groups in substituted form or an amino group including said group in substituted form, and 4) a polymer containing a plurality of alkylene oxide units and having a molecular weight of at least 1500, said ingredients 1), 2), 3) and 4) being present during said development in said aqueous medium in such amounts that when said photographic material is image-wise exposed through a continuous tone wedge and test developed in the thus constituted aqueous developing medium for a time of 45 s at 30 °C and fixed there results a silver wedge image corresponding with a log exposure versus density sensitometric curve wherein the maximum gradient (γ) is at least 5 and the product of said maximum gradient (γ) and of the gradient in the toe (γv) of said curve is at least 20; the maximum gradient is measured between the log exposure values corresponding with the densities 0.3 and 3.0 above fog of said curve and the gradient in the toe is measured between the log exposure values corresponding with the densities 0.1 and 0.6 above fog of said curve; the amount of the auxiliary developing agent in the photographic material being less than 10 mole % with respect to ingredient 1). A method according to claim 13, wherein the auxiliary developing agent is present in said photographic material in the range of 0.1 to 5 g/m². A method according to claim 12, wherein the concentration of said anti-fogging agent in said alkaline aqueous liquid is up to 1000 mg per litre. A method according to claim 12, wherein the auxiliary developing agent is p-amino-phenol, p-methylaminophenol, p-phenylene diamine sulphate, N,N-diethyl-p-phenylene diamine hydrochloride or a 1-phenyl-3-pyrazolidinone type developing agent or a mixture of at least two of them is used. A method according to claim 13, wherein the the auxiliary developing agent is p-amino-phenol, p-methylaminophenol, p-phenylene diamine sulphate, N,N-diethyl-p-phenylene diamine hydrochloride or a 1-phenyl-3-pyrazolidinone type developing agent or a mixture of at least two of them is used.

Inventors: DEWANCKELE JEAN-MARIE ODIL, KOK PIET, OOMS RICHARD ALFONS, DEWANCKELE, JEAN-MARIE ODIL, KOK, PIET, OOMS, RICHARD ALFONS
Applicants: AGFA GEVAERT NV, AGFA-GEVAERT NAAMLOZE VENNOOTSCHAP
Application year: 1990
Main classification: G03C5
IPC codes: C07D257, G03C5