EP0002763A2 - Photographic material with stabilisers and reversal process for producing a photograph - Google Patents

Abstract

In the reverse processing of photographic materials, thiocarbohydrazide derivatives can act both as stabilizers in the first developer and also favor the color development in the second developer such that a second exposure or a fogging bath before the second development can be dispensed with if necessary.

Description

The invention relates to a photographic material with at least one silver halide emulsion layer, which is improved by adding thiocarbohydrazide derivatives. The invention further relates to a method for producing photographic images in the presence of such compounds.

Photosensitive silver halide emulsions are known to tend to form fog, i.e. Germs that can be developed without exposure. Such fogging occurs increasingly with longer development times or development at higher temperatures. The formation of fog is disruptive both for materials which are subjected to a negative development and for materials which are subjected to reverse processing in the customary baths. For example, fog nuclei have the effect that silver halide is also reduced in the unexposed areas during reverse processing in the first developer, so that too little silver halide is available in the second development, with the result that the maximum densities obtained are too low.

It is known to add so-called antifoggants or stabilizers to photographic silver halide emulsions to reduce the formation of fog. Among other things, they have a stabilizing effect. heterocyclic mercapto compounds, e.g. those described in DT-AS 1 183 371, DT-OS 2 308 530 and DT-OS 1 622 271.

From DT-OS 2 548 880 inhibitors are also known which are present as escape groups of DIR compounds.

Such inhibitors and stabilizers can accumulate in the reverse processing during the first development on the remaining silver halide and hinder the second development, so that only reduced color densities are obtained.

In order to avoid such a hindrance to dye formation, it has been proposed in DT-OS 2 548 880 to treat the photographic materials with certain chemical fogging baths before the second development. However, the disadvantage of using such veiling baths is their instability.

It is therefore an object of the invention to find compounds for photographic materials with at least one silver halide emulsion layer which reduce fogging but avoid the disadvantages of known stabilizers and do not adversely affect the second development in reverse processing. Another object is to find a method for producing photographic images by processing photographic materials in the presence of such compounds.

It has now been found that certain thiocarbohydrazide derivatives are used in the processing of photographic materials in the usual black-and-white developers, such as those used as first developers in color reversal processes, act as a stabilizer, but do not have a development-inhibiting effect in reverse processing in the usual (color) secondary developers, but favor the color development in the second developer, possibly in such a way that on one Second exposure or the usual chemical fogging baths can be dispensed with.

worin bedeuten:

• _R ¹, _R ⁴ gleiche oder verschiedene Reste und zwar Wasserstoff, eine gesättigte oder olefinisch ungesättigte aliphatische Gruppe, Aryl, eine heterocyclische Gruppe oder Acyl;
• _R ², R gleiche oder verschiedene Reste und zwar Wasserstoff, eine gesättigte oder olefinisch ungesättigte aliphatische Gruppe, Aryl oder eine heterocyclische Gruppe;
• R⁵ = Wasserstoff;
  und/oder
• R zusammen mit _R ²
  und/oder
• R zusammen mit _R ⁴ Alkyliden, vorzugsweise eine gegebenenfalls durch Alkyl, Aryl, eine heterocyclische Gruppe oder Acyl substituierte Methylidengruppe, wobei zwei derartige Substituenten zusammen mit dem Kohlenstoffatom der Methylidengruppe einen carbocyclischen oder heterocyclischen Ring vervollständigen können, beispielsweise einen Cyclopentan-,Indan-, Indanon-, Indandion-, Piperidin-, Pyrrolidon- oder Indolonring. Beispiele für nicht ringgeschlossene substituierte Methylidengruppen sind Äthyliden, 3,3-Dimethyl-2-butyliden, Benzyliden und Furfuryliden; und/oder
• R zusammen mit _R ⁴ oder _R ⁵ den zur Vervollständigung eines 5- oder 6-gliedrigen heterocyclischen Ringes, insbesondere eines 1,2,3,4-Tetrazolidin-S-thionringes, eines Hexahydro-1,2,4,5-tetrazin-3-thionringes, eines Hexahydro-1,2,4-triazin-3-thionringes oder eines 2,3,4,5-Tetrahydro-1,2,4-triazin-3-thionringes erforderlichen Rest; hierbei handelt es sich in der Regel um eine Methylengruppe, die gegebenenfalls einfach oder zweifach weiter substituiert sein kann, z.B. mit Alkyl, Cycloalkyl, Aralkyl oder Aryl; zwei derartige Substituenten , z.B. zwei Alkylreste, können ihrerseits zusammen mit dem Kohlenstoffatom der Methylengruppe einen Ring, insbesondere einen carbocyclischen Ring bilden, wie beispielsweise einen Cyclopentan-, Cyclohexan- oder 3,3,5-Trimethylcyclohexanring.

A light-sensitive photographic material was found comprising: at least one silver halide emulsion layer and at least one compound of the following formula I.

in which mean:

• _R ¹ , _R ^{4 are} identical or different radicals, namely hydrogen, a saturated or olefinically unsaturated aliphatic group, aryl, a heterocyclic group or acyl;
• _R ² , R are identical or different radicals, namely hydrogen, a saturated or olefinically unsaturated aliphatic group, aryl or a heterocyclic group;
• R ⁵ = hydrogen;
  and or
• R together with _R ²
  and or
• R together with _R ⁴ alkylidene, preferably a methylidene group optionally substituted by alkyl, aryl, a heterocyclic group or acyl, where two such substituents together with the carbon atom of the methylidene group can complete a carbocyclic or heterocyclic ring, for example a cyclopentane, indane, indanone -, Indanedione, piperidine, pyrrolidone or indolone ring. Examples of non-ring-closed substituted methylidene groups are ethylidene, 3,3-dimethyl-2-butylidene, benzylidene and furfurylidene; and or
• R together with _R ⁴ or _R ⁵ to complete a 5- or 6-membered heterocyclic ring, in particular a 1,2,3,4-tetrazolidine S-thione ring, a hexahydro-1,2,4,5-tetrazine-3-thione ring, a hexahydro-1 , 2,4-triazine-3-thione ring or a 2,3,4,5-tetrahydro-1,2,4-triazine-3-thione ring; this is generally a methylene group which can optionally be mono- or disubstituted further, for example with alkyl, cycloalkyl, aralkyl or aryl; two such substituents, for example two alkyl radicals, can in turn form a ring, in particular a carbocyclic ring, together with the carbon atom of the methylene group, such as a cyclopentane, cyclohexane or 3,3,5-trimethylcyclohexane ring.

Examples of saturated aliphatic groups are alkyl radicals, which can be straight-chain, branched or cyclic and contain up to 18 carbon atoms and can be further substituted, for example with carboxyl, carbamoyl or nitrile.

A suitable olefinically unsaturated aliphatic group is, for example, allyl; suitable heterocyclic groups are, in particular, nitrogen-containing 5- or 6-membered rings, especially those mentioned above.

As aryl, in particular phenyl comes into question, which may be substituted, for example by halogen, hydroxyl, _A lkoxy, alkylthio, carboxyl, sulfamoyl, amino and / or alkyl. Acyl radicals are understood to be those which are derived from aliphatic or aromatic carboxylic or sulfonic acids, including (thio) carbonic acid monoesters, carbamic acids or sulfamic acids. Examples of such acyl radicals are acetyl, benzoyl, phenylsulfonyl, carbamoyl, phenylcarbamoyl, ethoxycarbonyl, ethoxythiocarbonyl.

The compounds of formula (I) may optionally be provided with a diffusion-proofing residue, e.g. with a long-chain alkyl or alkylene group, which is optionally linked via a hetero atom.

Particularly suitable compounds corresponding to formula (I) are those in which at least one of the radicals R ¹ and _R ^{4 is} an acyl radical with R ² , _R ³ and R ^{5 being} hydrogen, for example the following compounds:

The compounds according to the invention can be obtained from thiocarbohydrazide by known methods, as can be found, for example, in the literature in J. Indian Chem. Soc. 1, 141 and in J. Org. Chem. 34, 756.

Preparation of compound II

In a suspension of 53 g thiocarbohydrazide in 350 ml of pyridine, 116 ml of benzoyl chloride are added dropwise at a temperature of 25 ⁰ C with stirring and cooling. After the addition has ended, the mixture is stirred for a further 3 hours at room temperature and then mixed with 6 liters of water. The precipitate obtained is separated off, reprecipitated from methanol / water and, after drying in air, stirred with 1.7 liters of boiling ethyl acetate and, after cooling, filtered off with suction and air-dried. 112 g of 1,5-bisbenzoyl-thiocarbohydrazide are obtained, which melts at 177-179 ° C. with decomposition.

The invention further relates to a process for the production of photographic images by processing photographic materials in the presence of the substances to be used according to the invention.

• N,N-Dimethyl-p-phenylendiamin
• 4-Amino-3-methyl-N-Xthyl-N-methoxyäthylanilin Monomethyl-p-phenylendiamin
• 2-Amino-5-diäthylaminotoluol
• N-Butyl-N-ω-sulfobutyl-p-phenylendiamin
• 2-Amino-5-(N-äthyl-N-ß-methansulfonamidäthyl-amino)-toluol
• N-Äthyl-N-8-hydroxyäthyl-p-phenylendiamin
• N,N-Bis-(ß-hydroxyäthyl)-p-phenylendiamin
• 2-Amino-5-(N-äthyl-N-B-hydroxyäthylamino)-toluol und dergleichen.

The materials according to the invention can be processed by the customary methods with the customary developers. Examples of black and white developer substances that can be used are: hydroquinone, p-methylaminophenol and 1-phenyl-3-pyrazolidone. For example, the following can be used as color developer substances:

• N, N-dimethyl-p-phenylenediamine
• 4-amino-3-methyl-N-xthyl-N-methoxyethylaniline monomethyl-p-phenylenediamine
• 2-amino-5-diethylaminotoluene
• N-butyl-N-ω-sulfobutyl-p-phenylenediamine
• 2-Amino-5- (N-ethyl-N-ß-methanesulfonamidethyl-amino) -toluene
• N-ethyl-N-8-hydroxyethyl-p-phenylenediamine
• N, N-bis (ß-hydroxyethyl) -p-phenylenediamine
• 2-amino-5- (N-ethyl-NB-hydroxyethylamino) toluene and the like.

Further useful color developers are described, for example, in J.Amer.Chem.Soc. 73, 3100 (1951).

The usual silver halide emulsions are suitable for the present invention. These can contain silver chloride, silver bromide, silver iodide or mixtures thereof as silver halide.

The photographic material produced according to the invention can contain the usual color couplers, which are usually incorporated into the silver halide layers themselves. For example, the red-sensitive layer contains a non-diffusing color coupler for producing the blue-green partial color image, usually a coupler of the phenol or α-naphthol type. The green-sensitive layer contains at least one non-diffusing color coupler for producing the purple partial color image, color couplers of the 5-pyrazolone or indazolone type usually being used. Finally, the blue-sensitive layer unit contains at least one non-diffusing color coupler for producing the yellow partial color image, usually a color coupler with an open-chain ketomethylene grouping. Color couplers of these types are known in large numbers and are described in a large number of patents. Examples include the publication "Color Coupler" by W. Pelz in "Messages from the Research Laboratories of Agfa, Leverkusen / Munich", Volume III (1961) and K. Venkataraman in "The Chemistry of Synthetic Dyes", Vol. 4, 341 to 387 Academic Press 1971.

2-equivalent couplers can be used as non-diffusing color couplers; these contain a removable substituent in the coupling point, so that they only require two equivalents of silver halide to form the color, in contrast to the usual 4-equivalent couplers. The 2-equivalent couplers that can be used include, for example, the known DIR couplers, in which the cleavable residue after reaction with color developer oxidation products is set free as a diffusing development inhibitor. The so-called white couplers can also be used to improve the properties of the photographic material.

The non-diffusing color couplers and coloring compounds are added to the light-sensitive silver halide emulsions or other casting solutions by customary known methods. If the compounds are soluble in water or alkali, they can be added to the emulsions in the form of aqueous solutions, if appropriate with the addition of water-miscible organic solvents such as ethanol, acetone or dimethylformamide. If the non-diffusing color couplers and coloring compounds are water- or alkali-insoluble compounds, they can be emulsified in a known manner, for example by mixing a solution of these compounds in a low-boiling organic solvent directly with the silver halide emulsion or initially with an aqueous gelatin solution is, whereupon the organic solvent is removed in a conventional manner. A gelatin emulsate of the respective compound thus obtained is then mixed with the silver halide emulsion. If necessary, so-called coupler solvents or oil formers are additionally used to emulsify such hydrophobic compounds; these are usually higher boiling organic compounds which include the compounds in the form of oily droplets which split off the non-diffusing color coupler and development inhibitor to be emulsified in the silver halide emulsions. In this connection, reference is made, for example, to US Pat. Nos. 2,322,027; 2,533,514; 3,689,271; 3,764,336 and 3,765,897.

Gelatin is preferably used as the binder for the photographic layers. However, this can be replaced in whole or in part by other natural or synthetic binders. On natural binders e.g. Alginic acid and its derivatives such as salts, esters or amides, cellulose derivatives such as carboxymethyl cellulose, alkyl cellulose such as hydroxyethyl cellulose, starch or their derivatives such as ethers or esters or caragenates are suitable. Synthetic binders include polyvinyl alcohol, partially saponified polyvinyl acetate, polyvinyl pyrrolidone and the like.

The emulsions can also be chemically sensitized, e.g. by adding sulfur-containing compounds during chemical ripening, for example allyl isothiocyanate, allyl thiourea, sodium thiosulfate and the like. Reducing agents, e.g. the tin compounds described in Belgian patents 493 464 or 568 687, also polyamines such as diethylenetriamine or aminomethylsulfinic acid derivatives, e.g. according to Belgian patent 547 323.

Precious metals or noble metal compounds such as gold, platinum, palladium, iridium, ruthenium or rhodium are also suitable as chemical sensitizers. This method of chemical sensitization is described in the article by R. Koslowsky, Z.wiss.Phot. 46, 65-72, (1951).

It is also possible to sensitize the emulsions with polyalkylene oxide derivatives, e.g. with polyethylene oxide having a molecular weight between 1000 and 20,000, also with condensation products of alkylene oxides and aliphatic alcohols, glycols, cyclic dehydration products of hexitols, with alkyl-substituted phenols, aliphatic carboxylic acids, aliphatic amines, aliphatic diamines and amides. The condensation products have a molecular weight of at least 700, preferably more than 1000. To achieve special effects, these sensitizers can of course be used in combination, as described in Belgian patent 537 278 and British patent 727 982.

The emulsions can also be optically sensitized, e.g. B. with the usual polymethine, such as neutrocyanines, basic or acidic carbocyanines, rhodacyanines, hemicyanines, styryl dyes, oxonols and the like. Such sensitizers are in the work of F.M. Hamer 'The Cyanine Dyes andrelated Compounds', (1964).

• Azaindene, vorzugsweise Tetra- oder Pentaazaindene, insbesondere solche, die mit Hydroxyl- oder Aminogruppen substituiert sind. Derartige Verbindungen sind in dem Artikel von Birr, Z. Wiss. Phot. 47 (1952) 2 bis 58 beschrieben. Weitere geeignete Stabilisatoren sind u.a. heterocyclische Mercaptoverbindungen, z.B. Phenylmercaptotetrazol, quaternäre Benzthiazolderivate, Benztriazol und ähnliche.

The emulsions can additionally contain the usual stabilizers, such as:

• Azaindenes, preferably tetra- or penta-azaindenes, in particular those which are substituted by hydroxyl or amino groups. Such connections are described in the article by Birr, Z. Wiss. Phot. 47 (1952) 2 to 58. Other suitable stabilizers include heterocyclic mercapto compounds, for example phenyl mercaptotetrazole, quaternary benzothiazole derivatives, benzotriazole and the like.

The emulsions can be hardened in the usual manner, for example with formaldehyde or halogen-substituted aldehydes which contain a carboxyl group, such as mucobromic acid, diketones, methanesulfonic acid esters, dialdehydes and the like.

Furthermore, the photographic layers can be hardened with hardeners of the epoxy type, the heterocyclic ethylene imine or the acryloyl type. Examples of such hardeners are e.g. in German laid-open specification 2 263 602 or in British patent specification 1 266 655. Furthermore, it is also possible to harden the layers in accordance with the process of German Offenlegungsschrift 2 218 009 in order to obtain color photographic materials which are suitable for high-temperature processing.

It is also possible to harden the photographic layers or the color photographic multilayer materials with hardeners of the diazine, triazine or 1,2-dihydroquinoline series, as in British Patents 1 193 290, 1 251 091, 1 306 544, 1 266 655, French Patent 7 102 716 or German Laid-Open Specification 23 32 317. Examples of such hardeners are alkyl or arylsulfonyl group-containing diazine derivatives, derivatives of hydrogenated diazines or triazines, such as 1,3,5-hexahydrotriazine, fluoro-substituted diazine derivatives, such as fluoropyrimidine, esters of 2-substituted 1,2-dihydroquinoline or 1,2-dihydroisodhinoline-N-carboxylic acids. _V inylsulfonic acid hardeners, carbodlimide or carbamoyl hardeners can also be used, as described, for example, in German laid-open publications 22 63 602, 22 25 230 and 18 08 685, French patent specification 1,491,807, German patent specification 872,153 and GDR patent specification 7218. Other useful hardeners are described, for example, in British Patent 1,268,550.

The compounds to be used according to the invention can be introduced in diffusible or in diffusion-resistant form in at least one layer or intermediate layer of a photographic material both in emulsified and in dispersed or soluble form. They can be added to the light-sensitive silver halide emulsion layers after chemical ripening or the finished casting solution, or they can be applied together with the last protective layer. If necessary, the Compounds to be used according to the invention are introduced into the photographic materials before the first development by means of a bath.

The concentration of the compounds to be used according to the invention in the layers or in a bath can vary within wide limits. It depends on the desired effect and the composition of the photographic material. When used in a photographic layer, amounts of 1 ₀ ^-7 to 10 ^-4 mol per m ^{2 have been found to} be suitable. Quantities between 10 ^-6 and 10 ^-5 mol / m2 are preferred.

Even in the event that the compounds to be used according to the invention are to be bathed in the material before the first winding, optimal concentrations in the bath can easily be determined by a few simple manual tests. Here concentrations between 10 ^-6 to 10 ^-2 mol / 1 have proven to be sufficient. Concentrations between 10 ^{-5 -10 -3} _Mo l / _l treatment bath are particularly preferred.

The advantageous properties of the compounds to be used according to the invention are all the more astonishing since two mutually opposing effects can be specifically achieved here by means of a chemical substance: a stabilizing effect in the first development of photographic reversal materials and a concealing effect in the second development of photographic reversal materials. The compounds, in particular, for example, the compounds of the formula (II), can moreover have a stabilizing effect in the customary color-negative development.

Another characteristic of the compounds mentioned is their very uniform effect on the various emulsion layers, which, depending on the concentration of the compounds used, leads to a parallel shift of the gradations with the same development time or else allows a largely arbitrary adjustment of the first development time.

The advantageousness of the stabilizers to be used according to the invention is clear from the following examples, without the invention being restricted to the embodiments in these examples.

example

• Schicht 1: Eine Blaugrünschicht, enthaltend eine Silberbromidjodidemulsion mit 7 Mol-% Jodid, hergestellt gemäß Glafkides "Photographic Chemistry", Vol. 1, Seite 289 ff, Fountain Press, London 1958. Der Silbergehalt der Emulsion beträgt - ausgedrückt in AgN0₃ - 100 g pro kg Emulsion. Die Emulsion wird in bekannter Weise durch Zusätze von Schwefelverbindungen und Gold-I-Verbindungen gereift. Sie ist für den roten Spektralbereich sensibilisiert und enthält einen Farbkuppler folgender Formel:
  
• Schicht 2: Eine zweite Blaugrünschicht, enthaltend eine Silberbromidjodidemulsion mit 6 Mol-% Jodid, hergestellt nach dem unter Schicht 1 beschriebenen Verfahren, jedoch mit einer höheren Empfindlichkeit. Die Schicht enthält den gleichen Farbkuppler wie Schicht 1.
• Schicht 3: Eine Purpurschicht, enthaltend eine Silberbromidjodidemulsion wie unter Schicht 1 beschrieben, jedoch für den grünen Spektralbereich sensibilisiert. Sie enthält einen Kuppler folgender Formel:
  
• Schicht 4: Eine zweite Purpurschicht enthaltend eine Emulsion, wie unter Schicht 2 beschrieben, jedoch für den grünen Spektralbereich sensibilisiert und mit dem gleichen Kuppler wie Schicht 3.
• Schicht 5: Eine Gelbfilterschicht aus einem Silbersol.
• Schicht 6: Eine Gelbschicht, enthaltend eine Silberbromidjodidemulsion mit 4 Mol-% Jodid, hergestellt wie unter Schicht 1 beschrieben, die für den blauen Spektralbereich empfindlich ist. Die Schicht enthält einen Kuppler folgender Formel:
  
• Schicht 7: Eine weitere Gelbschicht enthaltend eine Silberbromidjodidemulsion mit 6 Mol-% Jodid, hergestellt wie unter Schicht 1 beschrieben, jedoch mit einer höheren Empfindlichkeit im blauen Spektralbereich als Schicht 6. Die Schicht enthält den gleichen Farbkuppler wie Schicht 6.
• Schicht 8: Der Aufbau wird mit einer Schutzschicht abgeschlossen. Die hierzu verwendete Gießlösung enthält neben dem Härtungs- und Netzmittel 1,6 % Gelatine. Auftrag entsprechend 50 ml/qm.

The following are applied in succession to a layer of cellulose triacetate with an antihalation layer made of black colloidal silver:

• Layer 1: A blue-green layer containing a silver bromoiodide emulsion containing 7 mole% iodide prepared according Glafkides "Photographic Chemistry", Vol 1, page 289 ff, Fountain Press, London, 1958. The silver content of the emulsion is - expressed in AgN0 _3-100. g per kg of emulsion. The emulsion is ripened in a known manner by adding sulfur compounds and gold I compounds. It is sensitized to the red spectral range and contains a color coupler with the following formula:
  
• Layer 2: A second cyan layer containing a silver bromide iodide emulsion with 6 mol% iodide, produced by the process described under layer 1, but with a higher sensitivity. The layer contains the same color coupler as layer 1.
• Layer 3: A purple layer containing a silver bromide iodide emulsion as described under layer 1, but sensitized to the green spectral range. It contains a coupler of the following formula:
  
• Layer 4: A second purple layer containing an emulsion as described under layer 2, but sensitized to the green spectral range and with the same coupler as layer 3.
• Layer 5: A yellow filter layer made of a silver sol.
• Layer 6: A yellow layer containing a silver bromide iodide emulsion with 4 mol% iodide, produced as described under layer 1, which is sensitive to the blue spectral range. The layer contains a coupler of the following formula:
  
• Layer 7: A further yellow layer containing a silver bromide iodide emulsion with 6 mol% iodide, produced as described under layer 1, but with a higher sensitivity in the blue spectral range than layer 6. The layer contains the same color coupler as layer 6.
• Layer 8: The structure is completed with a protective layer. The casting solution used for this contains 1.6% gelatin in addition to the hardening and wetting agent. Order corresponding to 50 ml / qm.

• A: Gießlösung ohne weiteren Zusatz
• B: Gießlösung mit 100 mg Vergleichssubstanz
• C: Gießlösung mit 100 mg Verbindung II
• D: Gießlösung mit 100 mg Verbindung V
• E: Gießlösung mit 200 mg Verbindung II
• F: Gießlösung mit 60 mg Verbindung III

Als Vergleichssubstanz wird das als Stabilisator bekannte 1-Phenyl-5-mercaptotetrazol verwendet.The casting solution for layer 8 is varied as follows (amount per liter of casting solution):

• A: Pouring solution without further addition
• B: Casting solution with 100 mg reference substance
• C: Casting solution with 100 mg of compound II
• D: Casting solution with 100 mg of compound V
• E: Casting solution with 200 mg of compound II
• F: Casting solution with 60 mg of compound III

1-Phenyl-5-mercaptotetrazole, known as a stabilizer, is used as the reference substance.

The materials are exposed imagewise in the usual way and subjected to reverse processing with the following baths:

Processing I

The photographic material is developed in the following first developer I for 8 minutes at 30 ° C. The photographic material is then subjected to a stop bath, watered, exposed twice and developed in developer II for 6 minutes. After the second development, it is stopped, washed, bleached and fixed, washed and dried as usual.

Developer I (concentration per liter)

Developer II (concentration per liter)

Processing II

• Die Zweitbelichtung wird ausgelassen, statt dessen wird das Material 2 Minuten mit einem wäßrigen Bad behandelt, welches lediglich 3₀ g NaOH pro Liter enthält.

The procedure is as indicated under processing 1 with the following change:

• The second exposure is omitted, instead the material is treated for 2 minutes with an aqueous bath which contains only 3 ₀ g NaOH per liter.

Während demnach bekannte Stabilisatoren die Farbstoffbildung im Zweitentwickler behindern, wird die Farbstoffbildung durch die erfindungsgemäß zu verwendenden Substanzen derart begünstigt, daß auf eine Zweitbelichtung verzichtet werden kann.The following maximum densities are obtained:

Accordingly, while known stabilizers hinder dye formation in the second developer, the dye formation is favored by the substances to be used according to the invention in such a way that a second exposure can be dispensed with.

Claims (5)

1. A method for producing images by processing photographic materials with at least one silver halide emulsion layer, characterized in that the processing of the photographic material is carried out in the presence of at least one compound of the following formula:

in what mean _R ¹ , _R ^{4 are the} same or different, hydrogen, a saturated or olefinically unsaturated aliphatic group, aryl, a heterocyclic group or acyl; _R ² , _R ^{3 are the} same or different, hydrogen, a saturated or olefinically unsaturated aliphatic group, aryl or a heterocyclic group; _R ^{5 is} hydrogen,
and or R ¹ together with _R ²
and or R together with R ^{4 is} a methylidene group optionally substituted by alkyl, aryl, a heterocyclic group or acyl, where two such substituents together with the carbon atom of the methylidene group can complete a carbocyclic or heterocyclic ring;
and or R ¹ together with R ⁴ or _R ^{5 is} the radical required to complete a 5- or 6-membered heterocyclic ring. 2. Light-sensitive photographic material with at least one silver halide emulsion layer, characterized by the content of at least one compound of the following formula:

in what mean _R ¹ , _R ^{4 are the} same or different, hydrogen, a saturated or olefinically unsaturated aliphatic group, aryl, a heterocyclic group or acyl; R ² _R ^{3 are the} same or different hydrogen, a saturated or olefinically unsaturated aliphatic group, aryl or a heterocyclic group; R ^{5 is} hydrogen;
and or R ¹ together with _R ²
and or R ³ together with R ^{4 is} a methylidene group optionally substituted by alkyl, aryl, a heterocyclic group or acyl, where two such substituents together with the carbon atom of the methylidene group can complete a carbocyclic or heterocyclic ring;
and or R together with R ⁴ or R ^{5 is} the radical required to complete a 5- or 6-membered heterocyclic ring. 3. Material according to claim 2, characterized in that in the formula R ¹ and / or R ⁴ denotes an acyl group which is derived from aliphatic or aromatic carboxylic or sulfonic acids, including carbonic acid monoesters, thiocarbonic acid monoesters, carbamic acids or sulfamic acids. 4. Material according to claim 2, characterized in that in the formula given R ¹ together with R ² and / or _R ³ together with R ^{4 represent} a methylidene group, which is part of a cyclopentane, cyclohexane, indane, indanone, indanedione -, piperidine, pyrrolidone or indolone ring. 5. Material according to claim 3, characterized in that R ² , _R ³ and _R ^{5 are} hydrogen.