US3847618A

US3847618A - Development of photographic silver halide material

Info

Publication number: US3847618A
Application number: US00361576A
Authority: US
Inventors: E Hofman; Bie L De; J Berendsen
Original assignee: Agfa Gevaert AG
Current assignee: Agfa Gevaert NV; Agfa Gevaert AG
Priority date: 1972-05-26
Filing date: 1973-05-18
Publication date: 1974-11-12
Anticipated expiration: 1991-11-12
Also published as: GB1417712A; FR2189770A1; FR2189770B1; CA1000993A; BE799642A; DE2324161A1; NL7307125A; JPS5630848B2; SU576977A3; IT1000421B; JPS4944745A; CH580828A5

Abstract

A method is described of producing high-contrast images by exposure and development of a photographic lith-type silver halide material wherein the lith material incorporates hydroquinone and development occurs by treating the exposed material with an alkaline development activator in the presence of hydroxylamine or a N-mono-substituted hydroxylamine. Processing time is reduced and the processing composition can be used for extended periods of time without replenishment. Favourable dot quality can be obtained.

Description

United States Patent Hofman et al.

DEVELOPMENT OF PHOTOGRAPI-IIC SILVER HALIDE MATERIAL Inventors: Emiel Alexander Hofman, Mortsel;

Leo Pierre De Bie, Kontich; Jules Robert Berendsen, Deurne, all of Belgium Assignee: AGFA-Gevaert, Mortsel, Belgium Filed: May 18, 1973 Appl. No.: 361,576

Foreign Application Priority Data May 26, 1972 Great Britain 25068/72 U.S. Cl 96/95, 96/66 R, 96/66.3 Int. Cl G03c 1/06, G03c 5/30 Field of Search 96/66 R, 66.3, 95, 76 R References Cited UNITED STATES PATENTS 3,128,180 4/1964 Henn r. 96/95 3,518,085 6/1970 Milton et al. 96/66.3 3,615,529 10/1971 Tajima et al 96/95 OTHER PUBLICATIONS Photo Sci. Eng. Vol. 17, No. 3, May/June 1973, pp. 255-260, Willems.

Primary ExaminerMary J. Kelley Attorney, Agent, or Firm-A. W. Breincr [57] ABSTRACT A method is described of producing high-contrast images by exposure and development of a photographic lith-type silver halide material wherein the lith material incorporates hydroquinone and development occurs by treating the exposed material with an alkaline development activator in the presence of hydroxylamine or a N-mono-substituted hydroxylamine. Processing time is reduced and the processing composition can be used for extended periods of time without replenishment Favourable dot quality can be obtained.

23 Claims, No Drawings DEVELOPMENT OF PHOTOGRAPHIC SILVER HALIDE MATERIAL The present invention relates to processing of exposed high-contrast silver halide materials for graphic arts use and particularly to processing of photographic silver halide materials of the lith type wherein the hydroquinone developing agent is incorporated into the said material.

In the photomechanical arts photographic films capable of providing high image contrast are required for the preparation of the line and halftonefilm intermediates, which are used in making printing plates. In reproducing continuous tone material, it is customary to make a halftone photographic intermediate, usually a film negative, in which the gradations in tone are represented by differing sizes of dots of uniform density. The shape, density and uniformity of the halftone dots are closely correlated to the quality of the resulting picture.

Lith-type emulsions are high-contrast fine-grain silver halide emulsions containing at least about 50 mole percent of silver chloride and at least about 5 mole percent of silver bromide. If desired they may comprise up to about 5 mole percent of silver iodide but generally the iodide content is less than about 1 mole percent. They have a characteristic curve with short toe and high-gamma and produce sharply defined images with high density extending to. the edges of lines and dots. This applies especially when a developer with so-called lith-effect is used. Up till now these lith-type developers comprise hydroquinone as the sole developing agent and have a very' low sulphite ion content, which is maintained at a low and constant value by the addition to the sulphite containing developing solution of formalin (paraformaldehyde) or by the direct addition to the solution of the addition product of sulphite and formalin namely sodium formaldehyde hydrogen sulphite. The mechanism of operation of these lith-type developers has been described by J. A. C. Yule in the J. Franklin Inst., 239 (l945), P. 221-230.

Ordinary lith-developers with low free sulphite content have the disadvantage of short life in storage and use because they tend to oxidize very rapidly; therefore, they must often be replaced or replenished.

Before use such developer solutions must be stored in two parts since the sodium formaldehyde hydrogen sulphite dissociates in the alkaline medium of the developer to form the sulphite ion as well as an equimolar amount of formaldehyde, which reacts with hydroquinone and destroys its developing power.

When used in continuous transport processing machines the commonly known lith-type developers for high-contrast films give rise to results of inferior quality as compared with careful tray processing as a result of locally varying concentration of the developing agent and its exhaustion products.

It is known for the development of silver halide material to incorporate one or more silver halide developing agents into the material itself and to effect development after exposure by treatment of the material with alkaline compositions substantially free of developing agents and called development activators. In this way the processing composition can be stored-for a very long time, it does not become exhaustedso easily and it need not be replenished.

Experiments which were carried out to extend these advantages to the processing of lith-material, by incorporating the sole developing agent hydroquinone into the lith-material and effecting development by means of an alkaline activator comprising sodium formaldehyde hydrogen sulphite, were not successful in that development was incomplete and the density of dots was unacceptable.

Accordingly itis an object of the present invention to provide a lith-type system wherein the hydroquinone developing agent is present in the lith-material and lithdevelopment is effected by means of an alkaline activator substantially free of hydroquinone developing agent.

It is a further object of the present invention to re-. duce development time of photographic silver halide elements of the lith-type yielding high-contrast and favourable dot-quality.

Another object of the present invention is to provide a processing composition for lithtype silver halide ele-, ments that is less liable to exhaustion and can be used for extended periods of time without replenishment.

It is also an object of the present invention to keep, during development, the concentration of hydroquinone locally constant, which is of particular value for automatic machine-processing.

The above objects and other objects, which will be apparent from the further disclosures, have been accomplished by incorporating the hydroquinone developing agent into the lith-type photographicsilver halide material and effecting development by means of an alkaline development activator in the presence of hy-. droxylamine or a N-monosubstituted hydroxylamine derivative. If so desired, two or more of said hydroxylamines may be used.

Particularly suitable hydroxylamines for use accord;- ing to the present invention. can be represented by the formula:

wherein R represents hydrogen, alkyl, e.g., methyl, ethyl, propyl, isopropyl, octyl, decyl, dodecyl, etc. in.-

cluding substituted alkyl e.g., alkyl substitutedibyanyl such as phenyl, hydroxy, carboxyl, sulpho, amino, sub.- stituted amino, and NHOH, or aryl including substituted aryl e.g., aryl substituted. by. halogen, alkyl; alkoxy, hydroxy, carboxyl, sulpho, alkoxycarbonyl, amino and substituted amino.

It will be understood that acid. addition salts of the hydroxylamine compoundsmay also be used in thisinvention which include, for. example,,sulphates, phosphates, carbonates, oxalates, acetates .andzchlorides. 0f

' course, the acid salt usedshould have no detrimental effect on the photographic material.

Representative examples of hydroxylamine compounds for use according to the present invention are. hydroxylamine, N-methylhydroxylamine, N-ethylhydroxylamine, N-propylhydroxylamine, N-ysulphopropylhydroxylamine, N-a-carboxypropylhydroxylamine, N-isopropylhydroxylamine, N-pheny-lhydroxylamine, a-hydroxylaminovfifphenyl propionic acid, N p-carboxyphenylhydrox-ylamine, N-pmethoxy-phenylhydroxylamine, N-mssulphophenylhydroxylamine, and

Z aorza-ca-cn -o-anon neon which can be prepared as described in Ber. 40, 218.

The present invention thus provides a method of pro: ducing high-contrast images by exposure and development of a photographic lith-type silver halide material, wherein said lith-type material incorporates hydroquinone as developing agent and development is effected by treatment of the exposed material with an alkaline development activator in the presence of hydroxylamine or a N-mono-substituted hydroxylamine.

As already noted above a lith-type silver halide material comprises a silver halide emulsion layer containing at least about 50 mole percent, preferably at least about 70 mole percent of silver chloride, at least about 5 mole percent of silver bromide and from to about mole percent of silver iodide. The average grain diameter is preferably comprised between about 0.1 and about 0.4 micron.

The hydroxylamine compound may be present in the alkaline solution or in the photographic lith-type material or in both. Therefore, the present invention also provides a photographic silver halide material as defined above containing hydroquinone which comprises in the said silver halide emulsion layer and/or in a hydrophilic colloid layer in water-permeable relationship therewith hydroxylamine or a N-monosubstituted hydroxylamine. In the lith-type silver halide material used in accordance with the present invention, the hydroquinone developing agent should be in effective contact or relationship with the silver halide, which means that it should be present in the silver halide emulsion layer itself and/or in one or more other hydrophilic colloid layers in water-permeable relationship with the silver halide emulsion layer e.g., a hydrophilic colloid intermediate layer arranged between the support and the silver halide emulsion layer or a hydrophilic colloid layer coated over the silver halide emulsion layer.

The alkaline development activator is normally free of hydroquinone developing agent. However, when the processing medium is used repeatedly for processing successive elements it may comprise after some time a minor amount of hydroquinone, which has diffused from the element into the processing medium.

According to a preferred embodiment of the present invention, a hydrophilic colloid intermediate layer e.g., a gelatin layer is arranged between the support and the light-sensitive silver halide emulsion layer of the lithmaterial.

Such hydrophilic colloid intermediate layer has a weight preferably comprised between about 2 and about g of hydrophilic colloid, more particularly gelatin, per sq.m.

The hydroquinone is preferably incorporated in .such hydrophilic colloid layerarranged between the support and the emulsion layer and/or in a hydrophilic colloid layer coated over the emulsion layer, e. g., a gelatin protective surface coating. V

The hydroquinone developing agent is incorporated into the lith-mate'rialin anamount preferably comprised between about 5 and about mmol per sq.m.

The hydroxylamine compounds may be used in widely varying amounts. Dependent on the particular compound involved they are used preferably in an amount comprised between about 0.5 g and about 50 g per litre of alkaline development activator. When used in the photographic element itself they are preferably used in amounts between about 50 mg and about 1 g per sq.m.

The silver halides are dispersed in hydrophilic colloid materials used as binders which include gelatin, collodion, gum arabic, casein, zein, cellulose ester derivatives such as alkyl esters of carboxylated cellulose, hydroxyethyl cellulose, carboxymethyl hydroxyethyl cellulose, alginic acid, polyvinyl alcohol and other synthetic resins well known in the art. Gelatin is preferably used as hydrophilic colloid binder. The binding agents for the emulsion layer may also contain dispersed polymerized vinyl compounds. Such compounds are disclosed e.g., in the US. Pat. Nos. 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 Nov. 6, 1962, 3,220,844 of Robert C. Houck, Donald A. Smith and Joseph S. Yudelson issued Nov. 30, 1965 and 3,518,085 of Kirby M. Milton and Charles A. Goffe issued June 30, 1970. They include the water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates, interpolymers of alkyl acrylates with acrylic acids, acryloyloxyalkylsulphonic acids, acetoacetoxyalkyl acrylates such as 2- acetoacetoxyethyl methacrylate and the like. These compounds may be incorporated likewise into a separate layer of the photographic element. The vinyl polymers may be employed in concentrations of about 20 to about 80 percent, most often concentrations of at least 50 percent by weight, based on the weight of the binding agent.

Silver halide emulsions wherein the binding agent contains a dispersed polymerised vinyl compound provide particularly good results in eliminating drag streaks and dot distortions.

Thev silver halide emulsions may be chemically sensitized by effecting the ripening in the presence of 'small amounts of sulphur-containing compounds such as allyl thiocyanate, ally] thiourea, sodium thiosulphate, etc. The emulsions may also be sensitized by means of reductors for instance tin compounds as described in United Kingdom Patent Specification No. 789,823 filed Apr. 29, 1955 by Gevaert Photo-Producten NV. and small amounts of noble metal compounds such as gold, platinum, palladium, iridium, ruthenium and rhodium compounds.

The emulsions may be used without being spectrally sensitized; however, it is advantageous to spectrally sensitize them according to methods well known in the art to make them ortho-sensitized or panchromatically sensitized. Spectral sensitizers that can be used are e.g., the cyanines, merocyanines, complex (trinuclear) cyanines, complex (trinuclear) merocyanines, styryl dyes, oxonol dyes and the like. Such like spectrally sensitizing dyes have been described by F. M. Hamer in The Cyanine dyes and relates compounds (1964).

The silver halide emulsion layer and/or other hydrophilic colloid layers of the high-contrast photographic elements, according to the present invention, can also contain conventional addenda for example, plasticizers, coating aids, antistaining agents, fog-inhibiting compounds and emulsion stabilizers e.g., the azaindenes, such as 5-methyl-7-hydroxy-s-triazolo[1,5- a]pyrimidine, and hardeners such as aldehyde hardeners, e.g., formaldehyde, mucochloric acid, glutaraldehyde bis(sodium hydrogen sulphite), maleic dialdehyde, aziridines, dioxan derivatives, and oxypolysac charides, as well as hardening agent precursor compounds which set free the effective hardener only in alkaline medium.

In the lith-type system of the present invention it is preferred to use polyoxyalkylene compounds, which may be present either in the lith-material or in the development activator or in both. These polyoxyalkylene compounds are widely known for use in lith-materials and/or lith developers and include any polymeric compound comprising a polyalkylene oxide chain e.g., polyethylene glycol, preferably having a molecular weight of 1500 or more and other ethylene oxide compounds as described amongst others in the United Kingdom Patent Specification Nos. 600,058 filed Jan. 10, 1946 by E. I. du Pont de Nemours, 871,801 filed Nov. 30, 1956 by Kodak Ltd., 920,637 filed May 7, 1959, 940,051 filed Nov. 1, 1961, 945,340 filed. Oct. 23, 1961, 949,643 filed Nov. 2, 1961 all by Gevaert Photo-Producten N.V., 991,608 filed June 14, 1961 by Kodak Ltd., 1,015,023 filed Dec. 24, 1962, 1,091,705 filed May 20, 1965 both by Gevaert Photo-Producten N.V. 1,107,022 filed Oct. 7, 1965, 1,147,817 filed Aug. 19, 1966, 1,162,135 filed Oct. 11, 1965, 1,184,434 filed Aug. 30, 1966 all byGevaert-Agfa N.V. in French PatentSpecification No. 1,416,850 filed Dec. 8, 1964 by Kodak Ltd., in the published German Patent Application Nos. 1,141,531 filed Jan. 24, 1962 by Perutz Photowerke GmbH, 1,188,439 filed May 16, 1964 by Fuji Shashin Film Kabushiki Kaisha, and in the U.S. Pat. Nos. 1,970,578 of Conrad Schoeller and Max Wittner issued Aug. 21, 1934, 2,240,472 of Donald R. Swan issued Apr. 29, 1941 2,423,549 of Ralph Kingsley Blake, William Alexander Stanton and Ferdinand Schulze issued July 8, 1947, 2,441,389 of Ralph Kingsley Blake, issued May 11, 1948 and 3,518,085 of Kirby M. Milton and Charles A. Goffe issued June 30, 1970.

The polyethylene oxide compounds may be present in the development activator in an amount ranging from about 0.1 g to about 1 g per litre. When used in the lith-material either in the silver. halide emulsion layer or an adjacent water-permeable insensitive layer they are preferably used in amounts ranging from about 0.010 g to about 1 g per mole of silver halide.

1n the lith-type system of the present invention, it is also possible to use in addition to the polyoxyalkylene 1 compound a N-vinyl-Z-pyrrolidone polymer or copolymer including addition complexes thereof with iodine as described in British Pat. No. 1,197,306 filed Sept. 19, 1966 by Agfa-Gevaert N.V. These N-vinyl-2- pyrrolidone polymers or copolymers may be used in the silver halide emulsion layer or in another hydrophilic colloid layer in water-permeable relationship with the emulsion layer as well as in the alkaline development activator.

As is known to those skilled in the art it may further be advantageous to use in the lith-material or processing solution therefor onium or polyonium compounds, preferably of the ammonium, phosphonium and sulphonium type or mixtures thereof. Specific onium compounds are e.g., dodecyl-trimethylammonium ptoluene sulphonate, nonyl pyridinium perchlorate,

mide, lauryl triethyl phosphonium bromide, onium salts.-

of polyoxyalkylenes e.g., polyoxyalkylene bispyridinium salts for example 1,1 '-[ethylenetris(oxyethylene) ]bis( pyridinium-p-tolusulphonate) etc. Further examples of suitable onium compounds can be found in U.S. Pat. Nos. 2,271,622 of BurtH. Carroll and Charles F. H. Allen issued Feb. 3, 1942, 2,271,623 of Burt H. Carroll issued Feb. 3, 1942, 2,275,727 of Burt H. Carroll and Charles F. H. Allen issued Mar. 10, 1942, 2,288,226 of Burt 11. Carroll and. Charles F. H. Allen issued June 30, 1942, 2,944,898 of Dorothy J. Beavers, Charles V. Wilson and James L. Graham issued July 12, 1960, 2,944,900 of Burt H. Carroll, Hubert S. Elins, James L. Graham and Charles V. Wilson issued July 12, 1960 and 2,944,902 of Burt H. Carroll, John Sagal Jr. and Dorothy J. Beavers issued July 12, 1960.

The silver halide lith-emulsions of use according to the invention may be coated on a wide variety of sup-, ports. Typical supports are cellulose nitrate film, cellulose ester film, polyvinyl acetal film, polystyrene film, poly(ethy1ene terephthalate) film, and related films of resinous materials, as well as glass, paper, metal and the like. Supports such as paper, which are coated with a-olefin polymers, particularly polymers of a-olefins containing two or more carbon atoms, as exemplified by polyethylene polypropylene, ethylene-butylene copolymers and the like can also be employed.

The lith-material may comprise all conventional layers used in silver halide elements e.g., subbing layers, filter layers, U.V.-absorbing layers, antistatic layers, protective surface coatings, etc.

The alkaline composition for effecting development of the exposed lith-material may comprise all kinds of ingredients as commonly employed in lith-type developers, for example thickening agents e.g., carboxymethylcellulose, compounds releasing halide ions e.g., potassium bromide, polyoxyalkylene compounds, N-vinyl-2-pyrrolidone polymers and copolymers, and onium compounds as referred to above, preservatives e.g., potassium metabisulphite, sodium formaldehyde hydrogen sulphite, and triethanolamine sulphite, watersoftening agents e.g., polyphosphates and derivatives of ethylenediamine, tetraacetic acid, wetting agents, etc. Preservatives for developing agents may also be incorporated into the hydroquinone-containing lith material. The processing solution may comprise low as well as high sulphite content since the hydroquinone developing agent is present in the silver halide element. The pH of the alkaline processing solution is generally at least about pH 9, preferably at least about pH 1 1.

After the development in accordance with the present invention the developed material may be fixed in the usual way e.g., by means of a water-soluble thiosulphate and then washed, or it may be treated with a stabilizing solution comprising an agent capable of converting non-exposed'silver halide in substantially lightinsensitive complexes, which need not be removed by washing, e.g., potassium and ammonium thiocyanate. Alternatively the developed material may be treated with a stabilizing and a fixing solution as described in U.S. Pat. No. 3,637,389 of Emiel A. Hofman issued Jan. 25, 1972.

Processing of the exposed photographic element can occur in an automatic apparatus wherein the exposed material is transported at a substantially constant speed through the processing stations. If desired, the exposure station may be coupled to the processing stations of the automatic apparatus.

A suitable automatic processing apparatus according to which the exposed element is transported through a development activating station, a stabilizing station, a fixing station and a rinsing station has been described in French Patent Specification No. 2,107,144 filed Sept. 1, l97l by Agfa-Gevaert N.V.

The following examples illustrate the present invention.

EXAMPLE 1.

A polyethylene terephthalate support was provided with a gelatin layer comprising hydroquinone in a ratio of 8 g of gelatin and 1.77 g of hydroquinone per sq.m. The gelatin layer was overcoated with a gelatino silver chlorobromoiodide emulsion (88.7 mole percent of chloride, 1 1 mole percent of bromide and 0.3 mole percent ofiodide) in such a way that per sq.m. an amount of silver halide corresponding to 6 g of silver nitrate waspresent. The silver halide emulsion layer was then overcoated with a gelatin antistress layer in a ratio of 0.3 g of gelatin per sq.m.

The light-sensitive material formed was divided into several aliquot strips. Under identical circumstances each strip was exposed through a step wedge with constant 0.15 and treated at 25C for increasing times in one of the following development activating compositions A, B and C:

COMPOSITION A anhydrous sodium carbonate potassium bromide l g water to make 1 sodium hydroxide to adjust pH to 12 COMPOSlTlON B Same as A but comprising in addition g of hydroxylamine sulphate.

COMPOSlTlON C Same as A but comprising in addition g of hydroxylamine sulphate.

8 The developed strips were then fixed, washed and dried in the usual way.

The results attained are listed in the following table.

Table Development Development Fog Gradient in toe amma activating time (sec) 10 solution A l5 0.04 2.52 3.15 30 0.04 2.77 2.l6 0.04 6.32 4.88 B 15 30 0.04 9.30 5.60 C 15 0.05 8.75 2.79 30 0.06 6.29 5.82

By gradient in toe is meant the average gradient measured between density 0.1 and 1 above fog.

The above results obtained with a development activating solution of very simple composition, clearly show that it is possible in accordance with the present invention to obtain a characteristic curve with short toe and high gamma.

EXAMPLE 2 A photographic material was prepared as described in example 1 and divided into several aliquot strips. Under identical circumstances, the strips were exposed through a step wedge with constant 0.15 and treated at 25C for increasing times in a development activating solution of the following composition:

anhydrous sodium carbonate I00 g sodium hydroxide 5 g 100 g triethanolamine sulphite 10 ml polyethylene glycol (molecular weight litre 4000) l g potassium bromide 0.6 g l, l '-[ethylene-tris(oxyethylene )]bis (pyridinium p-tolusulphonate) 100 mg water to make 1 litre (pH ll) to which one of the hydroxylamine compounds listed in the table below was added in the amount given.

The developed strips were then fixed, washed and dried in the usual way. The results attained were as follows.

3 of hydroxylamine Deva lop- Fog Gamma Gradient compound added moat in toe per litre time(s.eo)

. 40 0.05 2. '74 '1 '70 10 g of '(na oa) .n so 1o 0.04 6.35 4.58

5.5 g or NH H.HCl 10 0.04 6.50 5.02

6.4 g of H50 NHOH.HC1 10 0.04 6.05 4.86 20 0.04 5.86 4.26

a g of HONH-CH-CH -c 0 04 5 60 5 56 O 2 I I O NHOH 0.04 6.05 4.96

11.8 g of HO5S-(CH2)5-NHOH 10 L004 5.60 5.96

The above results show the favourable effect of treating the hydroquin0ne-containing lith-type silver halide material with an alkaline development activating solution in i the presence of hydroxylamine or a N- monosubstituted hydroxylamine.

EXAMPLE 3 MATERIAL I MATERIAL 11 Material 11 was prepared in exactly the same way as material I with the only difference that no hydroquinone was present in the first gelatin layer and that the gelatin antistress layer contained 1.6 g of hydroquinone per sq.m.

Both materials were exposed by the use of tungsten illumination through a step wedge and a grey contact screen.

After exposure the materials were developed for 30 sec. at 30C in the following development activating solution:

sodium carbonate 100 boric acid 10 hydroxylamine sulphate l0 tetrasodium salt of EDTA 1 potassium bromide l polyethylene glycol (molecular weight 4000) 1 water to make 1 The developed materials were fixed, washed and dried in the usual way.

The dot quality was evaluated in shadow (10 percent black dot coverage middle (50 percent black dot coverage) and highlight percent black dot coverage) tone areas and given a quality from 0, which is excellent to 4 which is extremely poor. Any dot quality above 3 is generally not acceptable.

1. Method of producing high-contrast images by exposure and development of a photographic lith-type sil-' ver halide material comprising a support and a silver halide emulsion layer containing at least about 50 mole percent of silver chloride, at least about 5 mole percent of silver bromide and from 0 to about 5 mole percent of silver iodide, wherein the said'photographic lith-type material incorporates hydroquinone as developing agent, and development is effected by treatment of the exposed material with an alkaline development activator in the presence of hydroxylamine or a salt thereof or of a N-monosubstituted hydroxylamine or a salt thereof. 1

2. Method according to claim 1, wherein a hydrophilic colloid intermediate layer is arranged between the support and the silver halide emulsion layer.

3. Method according to claim 2, wherein the said-hydrophilic colloid intermediate layer has a weight comprised between about 2 g and about 10 g of hydrophilic colloid per sq.m.

4. Method according to claim 1, wherein hydroquinone is present in the said hydrophilic colloid interntediate layer.

5. Method according to claim 1, wherein hydroquinone ispresent in a hydrophilic colloidcoating coated over the emulsion layer.

6. Method according to claim .1, wherein thehy droquinone is present in the lith material in an amount comprised betweenabout 5 millimole and about 25 millimole per sq.m.

7. Method according to claim 1, wherein the hydrox ylamine compound is present in the development activator.

8. Method according to claim 1 wherein the hydroxylamine used corresponds to the formula:

RNHOH wherein R is hydrogen, an alkyl group or an aryl group.

9. Method according to claim 7, wherein the hydroxylamine compound is present in the alkaline development activator in an amount comprised between about 0.5 g and about 50 g per litre.

10. Method according to claim 1, wherein the pH of the alkaline development activator is at least 9.

11. Method according to claim 1, wherein the lithmaterial and/or the alkaline development activator comprises a polyoxyethylene compound.

12. Method according to claim 1, wherein the lithmaterial and/or the alkaline development activator comprises a N-vinyl-2-pyrrolidone polymer or copolymer.

13. Method according to claim 1 wherein after development the material is fixed and washed.

14. Method according to claim 1, wherein after development the material is treated with a stabilizing solution comprising an agent converting non-exposed silver halide in light-insensitive complexes.

15. Method according to claim 14, wherein said agent is potassium or ammonium thiocyanate.

16. Method according to claim 14, wherein after treatment with the stabilizing solution the material is fixed and washed.

17. A photographic lith-type silver halide material comprising a support and a silver halide emulsion layer containing at least about 50 mole percent of silver chloride, at least about 5 mole percent of silver bromide and from to about m olepercent of silver iodide,

wherein said material incorporates hydroquinone and hydroxylamine or a salt thereof or a N-monosubstituted hydroxylamine or a salt thereof.

18. A photographic material according to claim 17, wherein said hydroxylamine compound corresponds to the formula:

RNHOH wherein R is hydrogen, an alkyl group or an aryl group.

19. A photographic material according to claim 17, wherein the hydroquinone is located in a hydrophilic colloid intermediate layer arranged between the support and the silver halide emulsion layer and/or a hydrophilic colloid layer coated over the silver halide emulsion layer.

20. A photographic material according to claim 17, wherein the hydroxylamine compound is present in the said emulsion layer and/or a hydrophilic colloid layer in water-permeable. relationship therewith.

21. A photographic material according to claim 19, wherein said intermediate layer has a weight comprised between about 2 g and about 10 g of hydrophilic colloid per sq.m.

22. A photographic material according to claim 17, wherein the hydroquinone is present in the lithmaterial in an amount comprised between about 5 millimole and about 25 millimole per sq.m.

23. A photographic material according to claim 17, wherein the hydroxylamine compound is present in the lith-material in an amount comprised between about 50 mg and about I g per sq.m.

Claims

1. A METHOD OF PRODUCING HIGH-CONTRAST IMAGES BY EXPOSURE AND DEVELOPMENT OF A PHOTOGRAPHIC LITH-TYPE SILVER HALIDE MATERIAL COMPRISING A SUPPORT AND A SILVER HALIDE EMULSION LAYER CONTAINING AT LEAST ABOUT 50 MOLE PERCENT OF SILVER CHLORIDE, AT LEAST ABOUT 5 MOLE PERCENT OF SILVER BROMIDE AND FROM 0 TO ABOUT 5 MOLE PERCENT OF SILVER IODIDE, WHEREIN THE SAID PHOTOGRAPHIC LITH-TYPE MATERIAL INCORPORATES HYDROQUINONE AS DEVELOPING AGENT, AND DEVELOPMENT IS EFFECTED BY TREATMENT OF THE EXPOSED MATERIAL WITH AN ALKALINE DEVELPMENT ACTIVATOR IN THE PRESENCE OF HYDROXYLAMINE OR A SALT THEREOF OR OF A N-MONOSUBSTITUTED HYDROXYLAMINE OR A SALT THEREOF.

3. Method according to claim 2, wherein the said hydrophilic colloid intermediate layer has a weight comprised between about 2 g and about 10 g of hydrophilic colloid per sq.m.

4. Method according to claim 1, wherein hydroquinone is present in the said hydrophilic colloid intermediate layer.

5. Method according to claim 1, wherein hydroquinone is present in a hydrophilic colloid coating coated over the emulsion layer.

6. Method according to claim 1, wherein the hydroquinone is present in the lith material in an amount comprised between about 5 millimole and about 25 millimole per sq.m.

7. Method according to claim 1, wherein the hydroxylamine compound is present in the development activator.

8. Method according to claim 1 wherein the hydroxylamine used corresponds to the formula: RNHOH wherein R is hydrogen, an alkyl group or an aryl group.

11. Method according to claim 1, wherein the lith-material and/or the alkaline development activator comprises a polyoxyethylene compound.

12. Method according to claim 1, wherein the lith-material and/or the alkaline development activator comprises a N-vinyl-2-pyrrolidone polymer or copolymer.

13. Method according to claim 1, wherein after development the material is fixed and washed.

17. A photographic lith-type silver halide material comprising a support and a silver halide emulsion layer containing at least about 50 mole percent of silver chloride, at least about 5 mole percent of silver bromide and from 0 to about 5 mole percent of silver iodide, wherein said material incorporates hydroquinone and hydroxylamine or a salt thereof or a N-monosubstituted hydroxylamine or a salt thereof.

18. A photographic material according to claim 17, wherein said hydroxylamine compound corresponds to the formula: RNHOH wherein R is hydrogen, an alkyl group or an aryl group.

20. A photographic material according to claim 17, wherein the hydroxylamine compound is present in the said emulsion layer and/or a hydrophilic colloid layer in water-permeable relationship therewith.

22. A photographic material according to claim 17, wherein the hydroquinone is present in the lith-material in an amount comprised between about 5 millimole and about 25 millimole per sq.m.

23. A photographic material according to claim 17, wherein the hydroxylamine compound is present in the lith-material in an amount comprised between about 50 mg and about 1 g per sq.m.