EP0447656A1 - Silver halide colour photographic material and its developing process - Google Patents

Abstract

A colour-photographic recording material having at least one blue-sensitive silver-halide emulsion layer containing at least one yellow coupler, at least one green-sensitive silver-halide emulsion layer containing at least one magenta coupler and at least one red-sensitive silver-halide emulsion layer containing at least one cyan coupler, and conventional intermediate layers and protective layers, in which the silver-halide concentration of all the photosensitive layers, indicated as AgNO3, is from 0.05 to 0.2 g/m<2> and a silver chloride bromide emulsion containing from 0.1 to 3 mol% of silver bromide is used as the emulsion in at least one photosensitive layer, can be developed with excellent results using a development/H2O2/intensification process.

Description

The invention relates to a color photographic silver halide material which is characterized on the one hand by a low application of silver halide and on the other hand by certain silver halide emulsions. Furthermore, the invention relates to a development process for the above-mentioned material, in which a combined action of developer and H₂O₂ is carried out.

Conventional silver halide materials for the production of color control formers each contain a blue-sensitive, green-sensitive and red-sensitive silver halide emulsion layer on a reflective support, to which yellow couplers, magenta couplers and cyan couplers are assigned in the order given. These materials also contain common intermediate and protective layers. In order to achieve sufficient color density during exposure and development by coupling the color couplers with the developer oxidation product, certain minimum amounts of silver halides are required, which on the other hand also ensure sufficient sensitivity during the copying process. Amounts of silver halide, given as AgNO₃, of at least 1 g / m² are currently in use across all 3 color densities.

In addition to the color image, the development creates a corresponding silver image, which has to be removed in order to make the colors appear clear and bright. This occurs in the silver removal stage following the development, which consists of the bleaching and fixing steps. The processing process is completed by watering or stabilizing and drying.

To lower the silver coating, it has also been proposed to combine the development with an enhancement process in which an enhancement solution containing H₂O₂ acts on the poorly developed color image and enhances it to such an extent that the usual color densities arise. This method has not yet been put into practice because the desired results were not achieved in continuous operation or extensive measures had to be taken to keep disruptive bromide and iodide ions away from the amplification baths, for example through the use of ion exchangers (DE-A 2 527 398, DE-A 3 228 192, DE-A 3 302 741, US-A 4 371 609, US-A 4 529 687).

In the previously proposed methods, silver chloride bromide emulsions with at least 30 mol% bromide and silver bromide iodide emulsion with high bromide contents were used. 100% silver chloride emulsions were also proposed, but did not produce sufficient results when reworked.

The object of the present invention was to find such a reinforcement method and a suitable material with which images of sufficient quality can be obtained simply and reliably.

The invention relates to a color photographic recording material with at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler, at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler and at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler as well as usual intermediate and protective layers, characterized in that the silver halide is applied all light-sensitive layers, indicated as AgNO₃, is 0.5 to 0.2 g / m² and in at least one light-sensitive layer, a silver chloride bromide emulsion with 0.1 to 3 mol% of silver bromide is used as the emulsion. Preferably there is at least 50%. of silver bromide on the surface of the silver halide grains. Such emulsions are obtained in particular by treating AgCl emulsions and AgClBr emulsions with a lower bromide content than desired after sensitization with the aqueous solution of a bromide.

The emulsions of all the light-sensitive layers are preferably AgClBr emulsions of the type mentioned, it being possible for the bromide fractions to differ from layer to layer within the inserted frame.

The silver halides preferably have a bromide content of 0.2-2 mol%.

In addition, the silver halide grains can contain up to 0.5 mol% of silver iodide, but are preferably free of silver iodide.

The color photographic recording material preferably consists of a reflective support, on which, in the order given, a layer sensitive to blue, containing at least one yellow coupler, a layer sensitive to green, to some extent containing a purple coupler, and a layer sensitive to red, containing at least one cyan coupler, and customary intermediate and protective layers are applied .

Another object of the invention is a development process for the above material, in which, after imagewise exposure, the material is treated with a color developer of the p-phenylenediamine series and aqueous H₂O₂.

The development can take place in one or two baths, the concentrations of color developer preferably being 0.01 to 0.1 mol / l and H₂O₂ being 0.5 to 25 g / l. The two-bath development (color developer and H₂O₂ in separate baths) is preferred.

Development and reinforcement can be followed by the usual bleaching, fixing, washing and drying steps, whereby bleaching and fixing can be carried out in one bath (bleach-fix bath). A particular advantage of the process, however, is that the small amount of silver halide produces such a weak silver image that the color image no longer interferes and therefore does not need to be removed. The bleaching can thus be omitted. Fixing (dissolving the unexposed silver halide) can also be omitted if the silver halide is converted into a light-insensitive silver complex salt by a stabilizing bath. In this case, the drying can immediately follow the stabilization.

In addition to the silver halide grains and the color couplers, the silver halide emulsion layers essentially contain a binder, which is also a main component of the intermediate and protective layers.

Gelatin is preferably used as the binder. However, this can be replaced in whole or in part by other synthetic, semi-synthetic or naturally occurring polymers. Synthetic gelatin substitutes are, for example, polyvinyl alcohol, poly-N-vinylpyrrolidone, polyacrylamides, polyacrylic acid and their derivatives, in particular their copolymers. Naturally occurring gelatin substitutes are, for example, other proteins such as albumin or casein, cellulose, sugar, starch or alginates. Semi-synthetic gelatin substitutes are usually modified natural products. Cellulose derivatives such as hydroxyalkyl cellulose, Examples of these are carboxymethyl cellulose and phthalyl cellulose and gelatin derivatives which have been obtained by reaction with alkylating or acylating agents or by grafting on polymerizable monomers.

The binders should have a sufficient amount of functional groups so that enough resistant layers can be produced by reaction with suitable hardening agents. Such functional groups are in particular amino groups, but also carboxyl groups, hydroxyl groups and active methylene groups.

The gelatin which is preferably used can be obtained by acidic or alkaline digestion. Oxidized gelatin can also be used. The production of such gelatins is described, for example, in The Science and Technology of Gelatine, published by A.G. Ward and A. Courts, Academic Press 1977, page 295 ff. The gelatin used in each case should contain the lowest possible level of photographically active impurities (inert gelatin). High viscosity, low swelling gelatins are particularly advantageous.

The silver halides used according to the invention can be predominantly compact crystals which are, for example, regularly cubic or octahedral or can have transitional forms. The silver halides can also be in the form of platelet-shaped crystals whose average ratio of diameter to thickness is, for example, at least 5: 1, the diameter of a grain being defined as the diameter of a circle with a circle content corresponding to the projected area of the grain. However, the layers can also have tabular silver halide crystals in which the ratio of diameter to thickness is substantially greater than 5: 1, for example 12: 1 to 30: 1.

The average grain size of the emulsions is preferably between 0.2 μm and 2.0 μm, the grain size distribution can be both homo- and heterodisperse. Homodisperse grain size distribution means that 95% of the grains do not deviate from the mean grain size by more than ± 30%. Homodisperse silver halide emulsions are preferred. In addition to the silver halide, the emulsions can also contain organic silver salts, e.g. Silver benzotriazolate or silver behenate.

Two or more kinds of silver halide emulsions, which are prepared separately, can be used as a mixture.

The photographic emulsions can be prepared using various methods (e.g. P. Glafkides, Chimie et Physique Photographique, Paul Montel, Paris (1967), GF Duffin, Photographic Emulsion Chemistry, The Focal Press, London (1966), VL Zelikman et al, Making and Coating Photographic Emulsion, The Focal Press, London (1966) from soluble silver salts and soluble halides.

The silver halide is preferably precipitated in the presence of the binder, for example the gelatin, and can be carried out in the acidic, neutral or alkaline pH range, silver halide complexing agents preferably being additionally used. The latter include, for example, ammonia, thioether, imidazole, ammonium thiocyanate or excess halide. The water-soluble silver salts and the halides are brought together either one after the other by the single-jet or simultaneously by the double-jet process or by any combination of the two processes. Dosing with increasing inflow rates is preferred, the "critical" feed rate, at which no new germs are being produced, should not be exceeded. The pAg range can vary within wide limits during the precipitation, preferably the so-called pAg-controlled method is used, in which a certain pAg value is kept constant or a defined pAg profile is traversed during the precipitation. In addition to the preferred precipitation with an excess of halide, so-called inverse precipitation with an excess of silver ions is also possible. In addition to precipitation, the silver halide crystals can also grow through physical ripening (Ostwald ripening), in the presence of excess halide and / or silver halide complexing agent. The growth of the emulsion grains can even take place predominantly by Ostwald ripening, a fine-grained, so-called Lippmann emulsion preferably being mixed with a less soluble emulsion and being redissolved on the latter.

Salts or complexes of metals such as Cd, Zn, Pb, Tl, Bi, Ir, Rh, Fe can also be present during the precipitation and / or physical ripening of the silver halide grains.

The precipitation can also be carried out in the presence of sensitizing dyes. Complexing agents and / or dyes can be rendered ineffective at any time, e.g. by changing the pH or by an oxidative treatment.

After crystal formation has been completed or at an earlier point in time, the soluble salts are removed from the emulsion, e.g. by pasta and washing, by flakes and washing, by ultrafiltration or by ion exchangers.

The silver halide emulsion is generally subjected to chemical sensitization under defined conditions - pH, pAg, temperature, gelatin, silver halide and sensitizer concentration - until the optimum sensitivity and fog are reached. The procedure is e.g. described by H. Frieser "The basics of photographic processes with silver halides" page 675-734, Akademische Verlagsgesellschaft (1968).

Chemical sensitization with the addition of compounds of sulfur, selenium, tellurium and / or compounds of the metals of subgroup VIII of the periodic table (for example gold, platinum, palladium, iridium) Furthermore, thiocyanate compounds, surface-active compounds such as thioethers, heterocyclic nitrogen compounds (eg imidazoles, azaindenes) or spectral sensitizers (described, for example, by F. Hamer "The Cyanine Dyes and Related Compounds", 1964, or Ullmann's Encyclopedia of Industrial Chemistry, 4th edition, vol. 18, p. 431 ff. And Research Disclosure 17643 (Dec. 1978), chapter III). Alternatively or additionally, a reduction sensitization with the addition of reducing agents (tin-II salts, amines, hydrazine derivatives, aminoboranes, silanes, formamidinesulfinic acid) can be carried out by hydrogen, by low pAg (eg less than 5) and / or high pH (eg above 8) .

The photographic emulsions may contain compounds to prevent fogging or to stabilize the photographic function during production, storage or photographic processing.

Azaindenes are particularly suitable, preferably tetra- and penta-azaindenes, in particular those which are substituted by hydroxyl or amino groups. Such connections are for example from Birr, Z. Wiss. Phot. 47 (1952), pp. 2-58. Salts of metals such as mercury or cadmium, aromatic sulfonic or sulfinic acids such as benzenesulfinic acid, or nitrogen-containing heterocycles such as nitrobenzimidazole, nitroindazole, optionally substituted benzotriazoles or benzothiazolium salts can also be used as antifoggants will. Heterocycles containing mercapto groups, for example mercaptobenzthiazoles, mercaptobenzimidazoles, mercaptotetrazoles, mercaptothiadiazoles, mercaptopyrimidines, are also suitable, these mercaptoazoles also being able to contain a water-solubilizing group, for example a carboxyl group or sulfo group. Other suitable compounds are published in Research Disclosure 17643 (Dec. 1978), Chapter VI.

The stabilizers can be added to the silver halide emulsions before, during or after their ripening. Of course, the compounds can also be added to other photographic layers which are assigned to a halogen silver layer.

Mixtures of two or more of the compounds mentioned can also be used.

The photographic emulsion layers or other hydrophilic colloid layers of the light-sensitive material produced according to the invention can contain surface-active agents for various purposes, such as coating aids, to prevent electrical charging, to improve the sliding properties, to emulsify the dispersion, to prevent adhesion and to improve the photographic characteristics ( eg acceleration of development, high contrast, sensitization etc.). In addition to natural surface-active compounds, eg saponin, synthetic surface-active compounds (surfactants) are mainly used:
non-ionic surfactants, for example alkylene oxide compounds, glycerol compounds or glycidol compounds, cationic surfactants, for example higher alkylamines, quaternary ammonium salts, pyridine compounds and other heterocyclic compounds, sulfonium compounds or phosphonium compounds, anionic surfactants, containing an acid group, for example carboxylic acid, sulfonic acid, a phosphoric acid, Sulfuric acid ester or phosphoric acid ester group, ampholytic surfactants, for example amino acid and aminosulfonic acid compounds as well as sulfuric or phosphoric acid esters of an amino alcohol. Also suitable are fluorine-containing surfactants, which are known, for example, from GB-PS 1 330 356, 1 524 631 and US-PS 3,666,478 and 3,689,906.

The photographic emulsions can be spectrally sensitized using methine dyes or other dyes. Particularly suitable dyes are cyanine dyes, merocyanine dyes and complex merocyanine dyes.

Research Disclosure 17643 (Dec. 1978), Chapter IV, provides an overview of the polymethine dyes suitable as spectral sensitizers, their suitable combinations and combinations having a super-sensitizing effect.

• 1. als Rotsensibilisatoren
  9-Ethylcarbocyanine mit Benzthiazol, Benzselenazol oder Naphthothiazol als basische Endgruppen, die in 5- und/oder 6-Stellung durch Halogen, Methyl, Methoxy, Carbalkoxy, Aryl substituiert sein können sowie 9-Ethyl-naphthoxathia- bzw. -selencarbocyanine und 9-Ethyl-naphthothiaoxa- bzw. -benzimidazocarbocyanine, vorausgesetzt, daß die Farbstoffe mindestens eine Sulfoalkylgruppe am heterocyclischen Stickstoff tragen.
• 2. als Grünsensibilisatoren
  9-Ethylcarbocyanine mit Benzoxazol, Naphthoxazol oder einem Benzoxazol und einem Benzthiazol als basische Endgruppen sowie Benzimidazocarbocyanine, die ebenfalls weiter substituiert sein können und ebenfalls mindestens eine Sulfoalkylgruppe am heterocyclischen Stickstoff enthalten müssen.
• 3. als Blausensibilisatoren
  symmetrische oder asymmetrische Benzimidazo-, Oxa-, Thia- oder Selenacyanine mit mindestens einer Sulfoalkylgruppe am heterocyclischen Stickstoff und gegebenenfalls weiteren Substituenten am aromatischen Kern, sowie Apomerocyanine mit einer Rhodaningruppe.

The following dyes, sorted by spectral range, are particularly suitable:

• 1. as red sensitizers
  9-ethyl carbocyanines with benzthiazole, benzselenazole or naphthothiazole as basic end groups, which can be substituted in the 5- and / or 6-position by halogen, methyl, methoxy, carbalkoxy, aryl, and 9-ethyl-naphthoxathia or -selencarbocyanines and 9- Ethyl-naphthothiaoxa- or -benzimidazocarbocyanine, provided that the dyes carry at least one sulfoalkyl group on the heterocyclic nitrogen.
• 2. as green sensitizers
  9-ethyl carbocyanines with benzoxazole, naphthoxazole or a benzoxazole and a benzthiazole as basic end groups, and also benzimidazocarbocyanines, which may also be further substituted and must likewise contain at least one sulfoalkyl group on the heterocyclic nitrogen.
• 3. as blue sensitizers
  symmetrical or asymmetrical benzimidazo, oxa, thia or selenacyanines with at least one sulfoalkyl group on the heterocyclic nitrogen and optionally further substituents on the aromatic nucleus, and apomerocyanines with a rhodanine group.

Color couplers for generating the blue-green partial color image are usually couplers of the phenol or α-naphthol type; Color couplers for producing the purple partial color image are generally couplers of the 5-pyrazolone, indazolone or pyrazoloazole type; Color couplers for producing the yellow partial color image are generally couplers with an open-chain ketomethylene group, in particular of the benzoylacetanilide and α-pivaloylacetanilide type. Numerous examples of the couplers are described in the literature. The couplers can also be of high molecular weight, so-called latex couplers.

High molecular weight color couplers are described, for example, in DE-C-1 297 417, DE-A-24 07 569, DE-A-31 48 125, DE-A-32 17 200, DE-A-33 20 079, DE-A-33 24 932, DE-A-33 31 743, DE-A-33 40 376, EP-A-27 284, US-A-4 080 211. The high molecular weight color couplers are usually produced by polymerizing ethylenically unsaturated monomeric color couplers. However, they can also be obtained by polyaddition or polycondensation.

The couplers or other compounds can be incorporated into silver halide emulsion layers by first preparing a solution, a dispersion or an emulsion of the compound in question and then adding it to the casting solution for the layer in question. The selection of the suitable solvent or dispersing agent depends on the solubility of the compound.

Methods for introducing compounds which are essentially insoluble in water by grinding processes are described, for example, in DE-A-26 09 741 and DE-A-26 09 742.

Hydrophobic compounds can also be introduced into the casting solution using high-boiling solvents, so-called oil formers. Corresponding methods are described, for example, in US-A-2 322 027, USA-A-2 801 170, US-A-2 801 171 and EP-A-O 043 037.

Instead of the high-boiling solvents, oligomers or polymers, so-called polymeric oil formers, can be used.

The compounds can also be introduced into the casting solution in the form of loaded latices. Reference is made, for example, to DE-A-25 41 230, DE-A-25 41 274, DE-A-28 35 856, EP-A-0 014 921, EP-A-0 069 671, EP-A-0 130 115, U.S.-A-4,291,113.

The diffusion-resistant incorporation of anionic water-soluble compounds (e.g. dyes) can also be carried out using cationic polymers, so-called pickling polymers.

Suitable oil formers are, for example, alkyl phthalates, phosphonic acid esters, phosphoric acid esters, citric acid esters, benzoic acid esters, amides, fatty acid esters, trimesic acid esters, alcohols, phenols, aniline derivatives and hydrocarbons.

Examples of suitable oil formers are dibutyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl phthalate, decyl phthalate, triphenyl phosphate, tricresyl phosphate, 2-ethylhexyl diphenyl phosphate, tricyclohexyl phosphate, tri-2-ethylhexyl phosphate, tridecoxy phosphate, 2-ethylhexyl phosphate, tridecoxy phosphate, 2-ethylhexyl phylate, , 2-ethylhexyl p-hydroxybenzoate, diethyldodecanamide, N-tetradecylpyrrolidone, isostearyl alcohol, 2,4-di-t-amylphenol, dioctyl acylate, glycerol tributyrate, isostearyl lactate, trioctyl citrate, N, N-octoxy-5-butyl-2-butyl , Paraffin, dodecylbenzene and diisopropylnaphthalene.

Each of the differently sensitized, light-sensitive layers can consist of a single layer or can also comprise two or more silver halide emulsion partial layers.

The non-light-sensitive intermediate layers, which are generally arranged between layers of different spectral sensitivity, can contain agents which prevent undesired diffusion of developer oxidation products from one light-sensitive layer into another light-sensitive layer with different spectral sensitization.

Suitable agents, which are also called scavengers or EOP-catchers, are described in Research Disclosure 17 643 (Dec. 1978), chapters VII, 17 842 (Feb. 1979) and 18 716 (Nov 1979), page 650 and in EP-AO 069 070, 0 098 072, 0 124 877, 0 125 522.

The photographic material can also contain UV light-absorbing compounds, whiteners, spacers, filter dyes, formalin scavengers, light stabilizers, antioxidants, D _min dyes, additives to improve dye, coupler and white stabilization and to reduce the color fog, plasticizers (latices), Contain biocides and others.

Compounds that absorb UV light are intended to protect the image dyes from fading due to UV-rich daylight. Connections of different structures are usually used for the two tasks. Examples are aryl-substituted benzotriazole compounds (US-A-3 533 794), 4-thiazolidone compounds (US-A-3 314 794 and 3 352 681), benzophenone compounds (JP-A-2784/71), cinnamic acid ester compounds (US-A-3 705 805 and 3,707,375), butadiene compounds (US-A-4,045,229) or benzoxazole compounds (US-A-3,700,455).

Particularly suitable UV absorbers should absorb light up to 400 nm and have a steep drop in their light absorption capacity at wavelengths above 400 nm.

Examples of particularly suitable compounds are

Filter dyes suitable for visible light include oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, cyanine dyes and azo dyes. Of these dyes, oxonol dyes, hemioxonol dyes and merocyanine dyes are used particularly advantageously.

Suitable whiteners are described, for example, in Research Disclosure 17,643 (Dec. 1978), Chapter V, in US-A-2,632,701, 3,269,840 and in GB-A-852,075 and 1,319,763.

Certain binder layers, in particular the most distant layer from the support, but also occasionally intermediate layers, especially if they are the most distant layer from the support during manufacture, may contain photographically inert particles of inorganic or organic nature, e.g. as a matting agent or as a spacer (DE-A-33 31 542, DE-A-34 24 893, Research Disclosure 17 643, (Dec. 1978), Chapter XVI).

The average particle diameter of the spacers is in particular in the range from 0.2 to 10 μm. The spacers are water-insoluble and can be alkali-insoluble or alkali-soluble, the alkali-soluble ones generally being removed from the photographic material in the alkaline development bath. Examples of suitable polymers are polymethyl methacrylate, copolymers of acrylic acid and methyl methacrylate and hydroxypropyl methyl cellulose hexahydrophthalate.

Additives to improve dye, coupler and whiteness stability and to reduce the color fog (Research Disclosure 17 643 (Dec. 1978), Chapter VII) can belong to the following chemical substance classes: hydroquinones, 6-hydroxychromanes, 5-hydroxycoumarans, spirochromans, spiroindanes , p-alkoxyphenols, sterically hindered phenols, gallic acid derivatives, methylenedioxybenzenes, aminophenols, sterically hindered amines, derivatives with esterified or etherified phenolic hydroxyl groups, metal complexes.

Compounds that have both a hindered amine partial structure and a hindered phenol partial structure in one molecule (US-A-4,268,593) are particularly effective in preventing the deterioration of yellow color images due to the development of heat, moisture and light. In order to prevent the deterioration of magenta color images, in particular their impairment as a result of exposure to light, spiroindanes (JP-A-159 644/81) and chromanes which are substituted by hydroquinone diethers or monoethers (JP-A-89 835 / 80) particularly effective.

The layers of the photographic material can be hardened with the usual hardening agents. Suitable curing agents are, for example, formaldehyde, glutaraldehyde and similar aldehyde compounds, diacetyl, cyclopentadione and similar ketone compounds, bis (2-chloroethyl urea), 2-hydroxy-4,6-dichloro-1,3,5-triazine and other compounds, the reactive halogen contain (US-A-3 288 775, US-A-2 732 303, GB-A-974 723 and GB-A-1 167 207), divinyl sulfone compounds, 5-acetyl-1,3-diacryloylhexahydro-1,3, 5-triazine and other compounds containing a reactive olefin bond (US-A-3 635 718, US-A-3 232 763 and GB-A-994 869); N-hydroxymethylphthalimide and other N-methylol compounds (US-A-2 732 316 and US-A-2 586 168); Isocyanates (US-A-3 103 437); Aziridine compounds (US-A-3 017 280 and US-A-2 983 611); Acid derivatives (US-A-2 725 294 and US-A-2 725 295); Carbodiimide type compounds (US-A-3 100 704); Carbamoylpyridinium salts (DE-A-22 25 230 and DE-A-24 39 551); Carbamoyloxypyridinium compounds (DE-A-24 08 814); Compounds with a phosphorus-halogen bond (JP-A-113 929/83); N-carbonyloximide compounds (JP-A-43353/81); N-sulfonyloximido compounds (US-A-4 111 926), dihydroquinoline compounds (US-A-4 013 468), 2-sulfonyloxypyridinium salts (JP-A-110 762/81), formamidinium salts (EP-A-0 162 308) , Compounds having two or more N-acyloximino groups (US-A-4 052 373), epoxy compounds (US-A-3 091 537), isoxazole-type compounds (US-A-3 321 313 and US-A-3 543 292); Halocarboxyaldehydes such as mucochloric acid; Dioxane derivatives such as dihydroxydioxane and di-chlorodioxane; and inorganic hardeners such as chrome alum and zirconium sulfate.

The hardening can be effected in a known manner by adding the hardening agent to the casting solution for the layer to be hardened or by overlaying the layer to be hardened with a layer which contains a diffusible hardening agent.

There are slow-acting and fast-acting hardeners and so-called instant hardeners, which are particularly advantageous, in the classes listed. Immediate hardeners are understood to mean compounds which crosslink suitable binders in such a way that the hardening is completed to the extent that no further change in the sensitometry and the change in the crosslinking reaction is caused by the crosslinking reaction Swelling of the layer structure occurs. Swelling is understood to mean the difference between the wet film thickness and the dry film thickness during the aqueous processing of the film (Photogr. Sci., Eng. 8 (1964), 275; Photogr. Sci. Eng. (1972), 449).

These hardening agents that react very quickly with gelatin are e.g. to carbamoylpyridinium salts, which are able to react with free carboxyl groups of the gelatin, so that the latter react with free amino groups of the gelatin to form peptide bonds and crosslink the gelatin.

• (a) worin

  R¹

  Alkyl, Aryl oder Aralkyl bedeutet,

  R²

  die gleiche Bedeutung wie R¹ hat oder Alkylen, Arylen, Aralkylen oder Alkaralkylen bedeutet, wobei die zweite Bindung mit einer Gruppe der Formel

  

  verknüpft ist, oder

  R¹ und R²

  zusammen die zur Vervollständigung eines gegebenenfalls substituierten heterocyclischen Ringes, beispielsweise eines Piperidin-, Piperazin- oder Morpholinringes erforderlichen Atome bedeuten, wobei der Ring z.B. durch C₁-C₃-Alkyl oder Halogen substituiert sein kann,

  R³

  für Wasserstoff, Alkyl, Aryl, Alkoxy, -NR⁴-COR⁵, -(CH₂)_m-NR⁸R⁹, -(CH₂)_n-CONR¹³R¹⁴ oder

  

  oder ein Brückenglied oder eine direkte Bindung an eine Polymerkette steht, wobei

  R⁴, R⁶, R⁷, R⁹, R¹⁴, R¹⁵, R¹⁷, R¹⁸, und R¹⁹

  Wasserstoff oder C₁-C₄-Alkyl,

  R⁵

  Wasserstoff, C₁-C₄-Alkyl oder NR⁶R⁷,

  R⁸

  -COR¹⁰

  R¹⁰

  NR¹¹R¹²

  R¹¹

  C₁-C₄-Alkyl oder Aryl, insbesondere Phenyl,

  R¹²

  Wasserstoff, C₁-C₄-Alkyl oder Aryl, insbesondere Phenyl,

  R¹³

  Wasserstoff, C₁-C₄-Alkyl oder Aryl, insbesondere Phenyl,

  R¹⁶

  Wasserstoff, C₁-C₄-Alkyl, -COR¹⁸ oder -CONHR¹⁹,

  m

  eine Zahl 1 bis 3

  n

  eine Zahl 0 bis 3

  p

  eine Zahl 2 bis 3 und

  Y

  0 oder NR¹⁷ bedeuten oder

  R¹³ und R¹⁴

  gemeinsam die zur Vervollständigung eines gegebenenfalls substituierten heterocyclischen Ringes, beispielsweise eines Piperidin-, Piperazin- oder Morpholinringes erforderlichen Atome darstellen, wobei der Ring z.B. durch C₁-C₃-Alkyl oder Halogen substituiert sein kann,

  Z

  die zur Vervollständigung eines 5- oder 6-gliedrigen aromatischen heterocyclischen Ringes, gegebenenfalls mit anelliertem Benzolring, erforderlichen C-Atome und

  X^⊖

  ein Anion bedeuten, das entfällt, wenn bereits eine anionische Gruppe mit dem übrigen Molekül verknüpft ist;

• (b)
  
  worin

  R¹, R², R³ und X^⊖

  die für Formel (a) angegebene Bedeutung besitzen.

Suitable examples of instant hardeners are, for example, compounds of the general formulas

• (a) where

  R¹

  Means alkyl, aryl or aralkyl,

  R²

  has the same meaning as R¹ or means alkylene, arylene, aralkylene or alkaralkylene, the second bond being with a group of the formula

  

  is linked, or

  R1 and R2

  together represent the atoms required to complete an optionally substituted heterocyclic ring, for example a piperidine, piperazine or morpholine ring, which ring can be substituted, for example, by C₁-C₃alkyl or halogen,

  R³

  for hydrogen, alkyl, aryl, alkoxy, -NR⁴-COR⁵, - (CH₂) _m -NR⁸R⁹, - (CH₂) _n -CONR¹³R¹⁴ or

  

  or a bridge link or a direct bond to a polymer chain, wherein

  R⁴, R⁶, R⁷, R⁹, R¹⁴, R¹⁵, R¹⁷, R¹⁸, and R¹⁹

  Hydrogen or C₁-C₄-alkyl,

  R⁵

  Hydrogen, C₁-C₄-alkyl or NR⁶R⁷,

  R⁸

  -COR¹⁰

  R¹⁰

  NR¹¹R¹²

  R¹¹

  C₁-C₄ alkyl or aryl, especially phenyl,

  R¹²

  Hydrogen, C₁-C₄ alkyl or aryl, especially phenyl,

  R¹³

  Hydrogen, C₁-C₄ alkyl or aryl, especially phenyl,

  R¹⁶

  Hydrogen, C₁-C₄-alkyl, -COR¹⁸ or -CONHR¹⁹,

  m

  a number 1 to 3

  n

  a number 0 to 3

  p

  a number 2 to 3 and

  Y

  0 or NR¹⁷ mean or

  R¹³ and R¹⁴

  together represent the atoms required to complete an optionally substituted heterocyclic ring, for example a piperidine, piperazine or morpholine ring, which ring may be substituted, for example, by C₁-C₃alkyl or halogen,

  Z

  the carbon atoms required to complete a 5- or 6-membered aromatic heterocyclic ring, optionally with a fused benzene ring, and

  X ^⊖

  mean an anion which is omitted if an anionic group is already linked to the rest of the molecule;

• (b)
  
  wherein

  R¹, R², R³ and X ^⊖

  have the meaning given for formula (a).

There are diffusible curing agents that have the same curing effect on all layers within a layer structure. There are also layer-limited, non-diffusing, low-molecular and high-molecular hardeners. They can be used to separate individual layers, e.g. crosslink the protective layer particularly strongly. This is important if the silver halide layer is hardened little because of the increase in silver opacity and the protective layer has to improve the mechanical properties (EP-A-0 114 699).

All developer compounds which have the ability to react in the form of their oxidation product with color couplers to form azomethine or indophenol dyes can be used as the color developer compound. Suitable color developer compounds are aromatic compounds of the p-phenylondiamine type containing at least one primary amino group, for example N, N-dialkyl-p-phenylenediamines such as N, N-diethyl-p-phenylenediamine, 1- (N-ethyl-N-methanesulfonamidoethyl) -3-methyl-p-phenylenediamine, 1- (N-ethyl-N-hydroxyethyl) -3-methyl-p-phenylenediamine and 1- (N-ethyl-N-methoxyethyl ) -3-methyl-p-phenylenediamine. Further useful color developers are described, for example, in J. Amer. Chem. Soc. 73 , 3106 (1951) and G. Haist, Modern Photographic Processing, 1979, John Wiley and Sons, New York, page 545 ff.

Treatment with aqueous H₂O₂ can be carried out simultaneously or after development.

After the color development and the H₂O₂ treatment, an acidic stop bath or watering as well as bleaching and fixing can follow, whereby bleaching and fixing can be dispensed with, particularly because of the small amounts of silver that are formed. Fixing can be replaced by stabilization.

For example, Fe (III) salts and Fe (III) complex salts such as ferricyanides, dichromates, water-soluble cobalt complexes can be used as bleaching agents. Iron (III) complexes of aminopolycarboxylic acids, in particular, for example, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitrilotriacetic acid, iminodiacetic acid, N-hydroxyethylethylenediaminetriacetic acid, alkyliminodicarboxylic acids and corresponding phosphonic acids are particularly preferred. Persulphates and peroxides, for example hydrogen peroxide, are also suitable as bleaching agents.

The bleach-fixing bath or fixing bath is usually followed by washing, which is designed as countercurrent washing or consists of several tanks with their own water supply.

Favorable results can be obtained using a subsequent final bath which contains little or no formaldehyde.

However, the washing can be completely replaced by a stabilizing bath, which is usually carried out in countercurrent. When formaldehyde is added, this stabilizing bath also functions as a final bath.

Preparation of the emulsions

A monodisperse silver chloride emulsion of 0.8 microns average grain diameter was prepared by double entry of an AgNO₃ and NaCl solution containing Na₄IrCl₆. The Ir content was 0.05 x 10⁻⁶ mol / mol Ag. The emulsion was flocculated in the usual way, washed and redispersed with gelatin. The weight ratio gelatin-silver (as AgNO₃) was 0.5. The AgCl content was 1 mol per kg of emulsion.

The emulsion was then ripened with 20 x 10⁻⁶ moles of thiosulfate and 2 x 10⁻⁶ moles of AuCl₄ per mole of Ag for optimal sensitivity. After the maturation, the emulsion was sensitized with blue sensitizer BS1 (400 x 10⁻⁶ mol / mol Ag) for the blue spectral range and then stabilized with stabilizer ST 1 (243 x 10⁻⁶ mol / mol Ag).

KBr solution was added to this starting emulsion in different amounts, based in each case on total silver:

Emulsion 7

According to EM 2, a green-sensitive emulsion with 99.5 mol%. Chloride, 0.5 mol% bromide and an average grain diameter of 0.4 microns (EM 7).

Emulsion 8

In accordance with EM 2, a red-sensitive emulsion with 99.5 mol% chlorine, 0.5 mol% bromide and a grain diameter of 0.35 μm was produced (EM 8).

example 1

A color photographic recording material was produced by applying the following layers in the order given to a support made of paper coated on both sides with polyethylene. The quantities given relate to 1 m². For the silver halide application, the corresponding amounts of AgNO₃ are given

Layer structure 1

• 1st layer (substrate layer):
  0.3 g gelatin
• 2nd layer (blue-sensitive layer)
  0.08 g AgNO₃ EM 1
  1.0 g gelatin
  0.6 g yellow coupler GB 1
  0.48 g tricresyl phosphate
• 3rd layer (protective layer):
  1.1 g gelatin
  0.06 g 2,5-dioctylhydroquinone
  0.06 g dibutyl phthalate
• 4th layer (green-sensitive layer):
  0.05 g AgNO₃ EM 7
  1.08 g gelatin
  0.4 g purple coupler PP 1
  0.43 g tricresyl phosphate
• 5th layer (UV protective layer):
  1.3 g gelatin
  0.56 g UV absorber UV 1
  0.3 g tricresyl phosphate
• 6th layer (red-sensitive layer)
  0.05 g AgNO₃ EM 8
  0.70 g gelatin
  0.38 g blue-green coupler BG 1
  0.38 g tricresyl phosphate
• 7th layer (UV protective layer)
  0.60 g gelatin
  0.2 g UV absorber UV 1
  0.1 g tricresyl phosphate
• 8th layer (hardener layer)
  0.9 g gelatin
  0.2 g of curing agent H 1

Examples 2 to 6

Further layer structures were produced by using 0.08 g of AgNO 3 EM 2 to EM 6 in layer 2.

Da die Menge des entwickelten Silbers sehr gering war, wurde auf eine Bleichstufe verzichtet.

The layer structures of Examples 1 to 6 thus produced were exposed imagewise by a sensitometer and developed as follows:

Since the amount of silver developed was very small, no bleaching stage was used.

Booster bath

Adjust aqueous hydrogen peroxide 0.5% by weight to pH 7.0 with KOH.

The processed and dried samples were measured behind blue, green and red filters. From the measurement results (Table 1) it can be seen that, firstly, without a bromide component, a sufficient maximum density but only an unsatisfactory sensitivity is achieved, secondly, the range of a favorable bromide component in the emulsion is very narrowly limited, and that outside of this range in one layer the other light-sensitive layers are also adversely affected.

Examples 7 to 12

Layer structures 1-6 were repeated with the change that 0.4 mg / m 2 of 5-butylbenzotriazole were added to the blue-sensitive emulsion. These layer structures 7-12 were also exposed by a sensitometer and developed as follows:

The measurement results, which are listed in Table 2, show that even when using a one-piece developer enhancer solution, the influence of the bromide content of the emulsion is decisive for the performance of the enhancement process.

Claims (9)

Color photographic recording material with at least one blue-sensitive silver halide emulsion layer containing at least one yellow coupler, at least one green-sensitive silver halide emulsion layer containing at least one magenta coupler and at least one red-sensitive silver halide emulsion layer containing at least one cyan coupler as well as customary intermediate and protective layers, characterized in that the silver halide coating is applied to all light-sensitive layers as AgNO₃, 0.05 to 0.2 g / m² and a silver chloride bromide emulsion with 0.1 to 3 mol% of silver bromide is used as an emulsion in at least one light-sensitive layer. The color photographic material of claim 1, wherein at least 50% of the silver bromide is on the surface of the silver halide grains. Color photographic recording material according to claim 1, characterized in that the silver bromide content is 0.2 to 2 mol% and the silver halide emulsion is iodide-free. Color photographic recording material according to claim 1, characterized in that the emulsions of all light-sensitive layers are AgClBr emulsions with 0.1 to 3 mol% of silver bromide. Color photographic recording material according to claim 4, characterized in that the bromide portions of the silver chlorobromides of the individual light-sensitive layers are different. Color photographic development process, characterized in that an imagewise exposed material according to claim 1 is subjected to color development and reinforcement with H₂O₂. Process according to Claim 6, characterized in that a color developer of the p-phenylenediamine series is developed in a concentration of 0.01 to 0.1 mol / l and an intensifying solution of 0.5 to 25 g H₂O₂ / l. A method according to claim 6, characterized in that development and reinforcement are carried out in one operation. A process for producing color images from a color photographic recording material according to claim 1 by developing and amplifying according to claim 6, fixing, washing and drying, in which no bleaching takes place.