EP0000511B1 - Photographic colour diffusion transfer process - Google Patents

Description

The invention relates to a process for the production of color photographic images by the dye diffusion transfer process and to a photographic material suitable therefor which contains new diffusion-resistant, color-providing compounds which liberate yellow diffusing azo dyes having a cyanoalkylamino group.

Among the processes known to date for the production of colored photographic images by the color diffusion transfer process, those based on the use of diffusion-resistant embedded color compounds, from which diffusing dyes or dye precursor products are separated imagewise during development and transferred to an image-receiving layer, have recently become increasingly important will.

The color-providing compounds suitable for this purpose include, for example, the non-diffusing color couplers described in DT-PS 1 095 115, which, during development, result from a reaction with the oxidation product of a color developer compound consisting of a primary aromatic amine, a pre-formed or at release the dye produced in a diffusing form. The selection of the developer compound required is naturally limited to color developers.

Furthermore, reference should be made to the non-diffusing coloring compounds described in DT-OS 1 930215, which contain a pre-formed latent diffusible dye residue linked to a diffusion-resistant residue via a cleavable hydrazone group. These compounds are not to be called color couplers, and it has also been shown that the choice of developer compounds which are required to release the diffusing dye residue is in no way limited to the usual color developers, but also that black and white developers, e.g. Catechins are very useful.

DT-OS 1 772 929 also describes non-diffusing colored compounds with a special grouping which undergo an oxidative ring closure reaction during development and thereby release a pre-formed dye residue in diffusing form. The connections presented there can be divided into two groups. The compounds of the one group require a customary color developer compound for development, with whose oxidation product they couple and in a subsequent ring closure reaction release the pre-formed dye residue in diffusing form. The compounds of the other group are themselves silver halide developing agents and are therefore able, even in the absence of further developer compounds in the oxidized form, to undergo the aforementioned ring closure reaction with the release of the diffusing dyes.

Finally, the non-diffusing coloring compounds of DT-OS 2 242 762 should also be mentioned at this point. These are sulfonamidophenols and sulfonamidoanilines which, after development during oxidation under the influence of developer alkali, cleave with the release of diffusing dyes with a free sulfamoyl group will.

The coloring compounds mentioned above work without exception negative, i.e. the image-wise distribution of the diffusing dye released arises when conventional (negative working) silver halide emulsions are used in accordance with the negative silver image produced during development. In order to generate positive dye images, it is therefore necessary to use direct-positive silver halide emulsions or else to use a suitable reversal process.

Non-diffusing coloring compounds are also known from DT-OSen 2 402 900 and 2 543 902, which in non-oxidized form are capable of a cleavage reaction under alkaline development conditions, whereby a diffusing dye is liberated, and in which on the other hand in oxidized form the above-mentioned cleavage reaction is made difficult or prevented. Such compounds are suitable in combination with conventional negative emulsions for producing positive transfer color images.

It is difficult to select suitable ones from the hitherto known coloring compounds which are satisfactory in every respect, both on the one hand with regard to their sufficient reactivity and on the other hand with regard to their sufficient stability. They should not release the diffusing dyes already during the alkaline development, but only after an imagewise oxidation by the imagewise developed silver halide has taken place. On the other hand, the diffusing dyes have to be released quickly enough either from the oxidized or from the non-oxidized form of the color-bound compounds, and a rapid transfer of the diffusing dyes is also necessary.

It is very important that the dyes can be set sufficiently in the image-receiving layer and that they also have excellent spectral properties and excellent stability against light and heat.

DT-OS 2 626 821 describes coloring compounds which provide yellow dyes for the color diffusion transfer process and which are to be distinguished by particularly advantageous absorption spectra and are said to have excellent color stability. However, it was found that the yellow dyes released from these color compounds left much to be desired in terms of their stability to light.

The invention is therefore based on the object of specifying new coloring compounds for the color diffusion transfer process, from which diffusing yellow dyes are set free during photographic processing, which have the desired spectral properties and good stain resistance, and which are furthermore distinguished by improved stability to light .

worin bedeuten

• A' einen gegebenenfalls über ein Bindeglied X angeknüpften einen diffusionsfestmachenden Rest enthaltenden oxidierbaren organischen Trägerrest in o-, m- oder p-Stellung zur Azogruppe, aus dem unter den Bedingungen der fotografischen Entwicklung entweder in oxidierter Form oder in nicht oxidierter Form durch Entwickleralkali mindestens ein Teil zusammen mit dem diffusionsfestmachenden Rest abgespalten wird unter gleichzeitiger bildmäßiger Freisetzung eines diffundierenden Azofarbstoffes;
• A² einen gegebenenfalls über ein Bindeglied X angeknüpften einen diffusionsfestmachenden Rest enthaltenden oxidierbaren organischen Trägerrest, der entweder direkt oder über einen der Substituenten R² und R³ in o- oder m-Stellung an den die Cyanalkylaminogruppe tragenden Phenylring angeknüpft ist und aus dem unter den Bedingungen der fotografischen Entwicklung entweder in oxidierter Form oder nichtoxidierter Form durch Entwickleralkali mindenstens ein Teil zusammen mit dem diffusionsfest machenden Rest abgespalten wird unter gleichzeitiger bildmäßiger Freisetzung eines diffundierenden Azofarbstoffes;
• A³ einen gegebenenfalls über ein Bindeglied X angeknüpften, einen diffusionsfest machenden Rest enthaltenden oxidierbaren organischen Trägerrest, der mit dem Substituenten R' verknüpft ist und aus dem unter den Bedingungen der fotografischen Entwicklung entweder in oxidierter Form oder in nichtoxidierter Form durch Entwickleralkali mindestens ein Teil zusammen mit dem diffusionsfestmachenden Rest abgespalten wird, unter gleichzeitiger bildmäßiger Freisetzung eines diffundierenden Azofarbstoffes;
• R¹ Wasserstoff, Alkyl mit 1 bis 5 C-Atomen, Aralkyl oder Aryl;
• R² und R³ (gleich oder verschieden), je einen der unter R¹ genannten Reste, Sulfo, -COOR⁴, Halogen, Trihalogenmethyl, Acylamino, Acyloxy (wobei die genannten Acylreste sich ableiten von aliphatischen oder aromatischen Carbon- oder Sulfonsäuren, einschließlich aliphatischer und aromatischer Carbaminsäuren und Kohlensäuremonoester), ferner Carbamoyl, Sulfamoyl, -OR⁴, -SR⁴, -SOR⁴, ―SO₂―R⁴, (wobei R⁴ eine der für R¹ angegebenen Bedeutungen hat), -N0₂ oder -CN;
• R⁵ und R⁶ (gleich oder verschieden) je einen Substituenten der für R² und R³ angegebenen Art, vorzugsweise Wasserstoff, Halogen wie Chlor, Alkyl wie Methyl, Alkoxy wie Methoxy, Acylamino wie Acetamino oder Nitro;
• X ein bivalentes Bindeglied der Formel
  
  worin R einen Alkylenrest mit 1 bis 6 C-Atomen oder einen gegebenenfalls substituierten Phenylrest bedeutet und wobei die beiden Reste R gleiche oder verschiedene Bedeutungen haben können;
• L -0-, -CO-, -CONR7, -S0₂NR⁷, ―O―CO―NR⁷, -S-, ―SO₂―, -SO- bedeutet (R⁷ = Wasserstoff oder Alkyl);
• p 0 oder 1
• q 0 oder 1, wobei q = 1, falls p = 1
• s 0 oder 1
• I, m, n jeweils 0 oder 1 mit der Maßgabe, daß I + m + n = 1
• r eine ganze Zahl von 1 bis 4, vorzugsweise 2 oder 3.

The present invention relates to a photographic color diffusion transfer process for the production of colored images, in which a photographic material with at least one light-sensitive silver halide emulsion layer and a non-diffusing coloring compound associated therewith is exposed imagewise and developed with a silver halide developing agent, a diffusing dye being imagewise formed by the developer alkali the non-diffusing coloring compound is split off and transferred to an image receiving layer. The process is characterized in that a compound of the following formula I is used as the non-diffusing coloring compound:

in what mean

• A 'an oxidizable organic carrier residue, optionally linked via a link X and containing a diffusion-fixing residue, in the o-, m- or p-position to the azo group, from which, under the conditions of photographic development, either in oxidized form or in non-oxidized form by developer alkali Part is split off together with the diffusion-proofing residue with simultaneous imagewise release of a diffusing azo dye;
• A ^{2 is} an oxidizable organic carrier residue, optionally linked via a link X, which contains a diffusion-proofing residue and which is attached either directly or via one of the substituents R ² and R ³ in the o- or m-position to the phenyl ring bearing the cyanoalkylamino group and from which under the Conditions of photographic development either in oxidized form or non-oxidized form by means of developer alkali, at least part of it is split off together with the rest that makes diffusion resistant, with simultaneous imagewise release of a diffusing azo dye;
• A ^{3 is} an oxidizable organic carrier residue which is optionally linked via a link X and contains a diffusion-proofing residue and which is linked to the substituent R 'and from which at least part together under the conditions of photographic development either in oxidized form or in non-oxidized form by developer alkali is split off with the diffusion-proofing residue, with simultaneous imagewise release of a diffusing azo dye;
• R ^{1 is} hydrogen, alkyl having 1 to 5 carbon atoms, aralkyl or aryl;
• R ² and R ³ (identical or different), each one of the radicals mentioned under R ¹ , sulfo, -COOR ⁴ , halogen, trihalomethyl, acylamino, acyloxy (the acyl radicals mentioned being derived from aliphatic or aromatic carboxylic or sulfonic acids, including aliphatic and aromatic carbamic acids and carbonic acid monoesters), also carbamoyl, sulfamoyl, -OR ⁴ , -SR ⁴ , -SOR ⁴ , ―SO ₂ ―R ⁴ , (where R ^{4 has} one of the meanings given for R ¹ ), -N0 ₂ or -CN;
• R ⁵ and R ⁶ (identical or different) each have a substituent of the type indicated for R ² and R ³ , preferably hydrogen, halogen such as chlorine, alkyl such as methyl, alkoxy such as methoxy, acylamino such as acetamino or nitro;
• X is a bivalent link of the formula
  
  in which R is an alkylene radical having 1 to 6 carbon atoms or an optionally substituted phenyl radical and the two radicals R can have the same or different meanings;
• L denotes -0-, -CO-, -CONR7, -S0 ₂ NR ⁷ , ―O ― CO ― NR ⁷ , -S-, ―SO ₂ -, -SO- (R ⁷ = hydrogen or alkyl);
• p 0 or 1
• q 0 or 1, where q = 1 if p = 1
• s 0 or 1
• I, m, n each 0 or 1 with the proviso that I + m + n = 1
• r is an integer from 1 to 4, preferably 2 or 3.

der entweder über den Rest R¹ oder über einen der beiden dargestellten Benzolringe mit einem diffusionsfestmachenden oxidierbaren organischen Trägerrest verbunden ist. Dieser Trägerrest ist dabei von solcher Art, daß er entweder in oxidierter Form oder in nichtoxidierter Form unter den Bedingungen der fotografischen Entwicklung durch Entwickleralkali aus den farbgebenden Verbindungen abgespalten wird, so daß diffundierende Azofarbstoffe in Freiheit gesetzt werden. Trägerreste A', A², A³ mit derartigen Funktionen sind bekannt. Hier sei beispielsweise auf die in der eingangs erwähnten DT-OS 2 242 762 beschriebenen Sulfonamidophenole und Sulfonamidoaniline hingewiesen, die nach der bei der Entwicklung erfolgten Oxidation unter Einfluß des Entwickleralkalis unter Freisetzung diffundierender Farbstoffe mit einer freien Sulfonamidgruppe gespalten werden. Weiterhin sei beispielsweise verwiesen auf die in DT-OS 2 505 248 und in der deutschen Patentanmeldung P 2 645 656.4 beschriebenen Verbindungen, z.B. die 3-Sulfonamidoindolverbindungen, die in ähnlicher Weise, wenn sie oxidiert sind, einer Spaltung durch das Entwickleralkali unterliegen und hierbei diffundierende Farbstoffe in Freiheit setzen. Auch diese Verbindungen ermöglichen somit einen Farbübertrag an Stellen, in denen eine Entwicklung stattfindet. Weiterhin müssen an dieser Stelle die DT-OSen 2 402 900 und 2 543 902 erwähnt werden. In diesen beiden Offenlegungsschriften sind farbgebende Verbindungen beschrieben, die in einer Spaltungsreaktion unter alkalischen Entwicklungsbedingungen aus der nichtoxidierten Form diffundierende Farbstoffe in Freiheit setzen und bei denen andererseits inoxidierter Form die oben erwähnte Spaltungsreaktion erschwert oder verhindert wird. Derartige Verbindungen ermöglichen somit einen Farbübertrag nur an solchen Stellen, in denen nicht eine durch die Entwicklung bedingte Oxidation stattgefunden hat. Sie sind somit zur Herstellung positiver Übertragsbilder geeignet.The coloring compounds according to the invention thus contain an azo dye residue of the formula

which is connected to a diffusion-proofing oxidizable organic carrier residue either via the radical R ¹ or via one of the two benzene rings shown. This carrier residue is of such a type that it is split off from the coloring compounds either in oxidized form or in non-oxidized form under the conditions of photographic development by developer alkali, so that diffusing azo dyes are released. Carrier residues A ', A ² , A ³ with such functions are known. Attention is drawn here, for example, to the sulfonamidophenols and sulfonamidoanilines described in the above-mentioned DT-OS 2 242 762, which are cleaved with a free sulfonamide group after the oxidation during development under the influence of the developer alkali with the release of diffusing dyes. Furthermore, reference may be made, for example, to the compounds described in DT-OS 2 505 248 and in German patent application P 2 645 656.4, for example the 3-sulfonamidoindole compounds which, when oxidized, are similarly subject to cleavage by the developer alkali and thereby diffusing Set dyes free. These connections therefore also enable color transfer at locations where development takes place. DT-OSen 2 402 900 and 2 543 902 must also be mentioned here. In these two published documents, coloring compounds are described which release dyes which diffuse from the non-oxidized form in a cleavage reaction under alkaline development conditions and in which, on the other hand, the above-mentioned cleavage reaction is made more difficult or prevented in oxidized form. Such compounds thus enable color transfer only at those points in which oxidation has not occurred due to development. They are therefore suitable for producing positive carry images.

worin die Symbole R¹, R²,R³, R⁵, R⁶, X, r und s die bereits angegebene Bedeutung haben und A⁴ den mit mindestens einem diffusionsfestmachenden Rest substituierten Rest einer der folgenden Formeln bedeutet:

worin

• Z für einen diffusionsfestmachenden Rest steht
• Y' für einen zur Vervollständigung eines Benzol- oder Naphthalinringes erforderlichen Rest steht
• Y" für einen zur Vervollständigung eines ankondensierten, gegebenenfalls substituierten carbocyclischen oder heterocyclischen Ringes steht, und
• R^B Wasserstoff, Alkyl, Alkoxy, Aryl, eine heterocyclische Gruppe Carboxyl, Carbamoyl oder Alkoxycarbonyl bedeutet.
• A⁴ stellt somit in der bevorzugten Ausführungsform der vorliegenden Erfindung zusammen mit der verknüpfenden ―NH―SO₂― Gruppierung einen nicht diffundierenden oxidierbaren organischen Trägerrest dar, und zwar einen solchen Trägerrest, der nur in oxidierter Form einer Spaltung durch das Entwickleralkali unterliegt. Eine Farbstoffdiffusion findet daher nur an den Stellen im fotografischen Material statt, in denen eine Silberhalogenidentwicklung erfolgt. Farbgebende Verbindungen mit Trägerresten der durch A⁴ dargestellten Art sind beschrieben in DT-OS 2 242 762, in DT-OS 2 505 248 und der deutschen Patentanmeldung P 2 645 656.4.

Particularly preferred compounds of the present invention correspond to the following formula II:

wherein the symbols R ¹ , R ² , R ³ , R ⁵ , R ⁶ , X, r and s have the meaning already indicated and A ⁴ denotes the radical of one of the following formulas which is substituted by at least one diffusion-proofing radical:

wherein

• Z stands for a diffusion-proofing residue
• Y 'represents a residue required to complete a benzene or naphthalene ring
• Y "stands for the completion of a condensed, optionally substituted carbocyclic or heterocyclic ring, and
• R ^{B represents} hydrogen, alkyl, alkoxy, aryl, a heterocyclic group carboxyl, carbamoyl or alkoxycarbonyl.
• A ⁴ thus represents in the preferred embodiment of the present invention together with the linking ―NH ― SO ₂ grouping a non-diffusible oxidizable organic carrier residue, specifically a carrier residue which is only subjected to cleavage by the developer alkali in oxidized form. Dye diffusion therefore only takes place at those points in the photographic material where silver halide development takes place. Color-imparting compounds with carrier residues of the type represented by A ⁴ are described in DT-OS 2 242 762, in DT-OS 2 505 248 and the German patent application P 2 645 656.4.

-CH₂-CH₂-SO₂-C₆H₁₂- und -C₃H₆-NH-CO-C₂H₄-.The bivalent link X shown in general formulas I and II can, for example, be a residue of one of the following formulas:

-CH ₂ -CH ₂ -SO ₂ -C ₆ H ₁₂ - and -C ₃ H ₆ -NH-CO-C ₂ H ₄ -.

It should be pointed out that the coloring compounds according to the invention should not diffuse as intact molecules in the layers of the photographic material. For this purpose they contain a diffusion-proofing residue, e.g. the rest Z.

Adequate diffusion resistance of the color-providing compounds can already be provided even if the color-providing compounds do not contain any longer alkyl residues, since the molecule can also have a sufficient size, depending on the dye residue. Otherwise it is possible to make the coloring compounds sufficiently diffusion-resistant by selecting residues of a suitable size.

Those residues which make it possible to store the compounds according to the invention in a diffusion-resistant manner in the hydrophilic colloids usually used in photographic materials are to be regarded as diffusion-fixing residues. For this purpose, organic radicals are preferably suitable which generally contain straight-chain or branched aliphatic groups and optionally also isocyclic or heterocyclic or aromatic groups with generally 8 to 20 C atoms. With the rest of the molecule these residues are either directly or indirectly, e.g. about one of the. the following groups: -NHCO-, -NHS02--, -NR-, where R is hydrogen or alkyl, -0- or -S-. In addition, the diffusion-proofing residue may also contain water-solubilizing groups, e.g. Sulfo groups or carboxyl groups, which can also be in anionic form. Since the diffusion properties depend on the molecular size of the total compound used, it is sufficient in certain cases, e.g. if the total molecule used is large enough to use shorter-chain residues as "diffusion-proofing residues".

During development, at least part of the carrier residue is split off from the non-diffusing coloring compounds according to the invention together with the diffusion-proofing residue with the liberation of a diffusing azo dye. At the same time, chemical conversion can take place in the split off carrier residue, e.g. an intramolecular rearrangement in the form of a ring closure reaction.

wobei R¹, R², R³, R⁵, R⁶, r und s die bereits angegebene Bedeutung haben.The released diffusing azo dyes have, for example in the case of the non-diffusing coloring compounds of the formula 11, a free sulfamoyl group and correspond to the following formula III

where R ¹ , R ² , R ³ , R ⁵ , R ⁶ , r and s have the meaning already given.

Verbindung Nr. 10

Examples of suitable coloring compounds according to the present invention are the following:

Compound No. 10

λmax: 420 nm

Preparation of Compound No. 2

a) 3- (4-N-Methyl-N-cyanoethyl-aminobenzene-azo) -4-chlorobenzenesulfonic acid

To a suspension of 69.2 g in 500 ml of 3-amino-4-chlorobenzene sulphonic acid (90%) H ₂ 0 and 90 ml concentrated hydrochloric acid was added a solution of 20.7 g of sodium nitrite in 60 ml H ₂ O at 0-5 ° C added dropwise. The suspension was stirred for 30 minutes. Excess nitrite was destroyed with sulfamic acid. The suspension was introduced at 5-10 ° C. into a solution of 48 g of 3- (N-methylanilino) propiononitrile in 240 ml of acetone. The pH was then adjusted to 3.5 with 20% sodium acetate solution. The mixture was stirred at 5-10 ° C. for 3 hours and then overnight without cooling. The dye was filtered off, washed with 10% saline and dried. Yield 93 g; Mp .:> 225 ° (Z).

b) 3- (4-N-Methyl-N-cyanoethyl-aminobenzene-azo) -4-chlorobenzenesulfonic acid chloride

22.8 ml of POCI ₃ were introduced into an initial charge of 140 ml of dimethylformamide. The solution was cooled to 25 ° C. and 19 g of 3- (4-N-methyl-N-cyanoethyl-aminobenzene-azo) -4-chlorobenzenesulfonic acid were introduced at 25 ° C. The mixture was stirred at 25 ° C for 1 hour. The mixture was then carried out on ice and the precipitated jelly was suctioned off, washed with water and dried. Yield 18 g; Mp .: _> 155 ° (Z).

c) Compound No. 2.

die durch Unsetzung von 2-(2,4-Ditert.-pentylphenoxybutylamino-carbonyl)-3-amino-5-methoxy-indol (dessen Darstellung nach einer in der deutschen Patentanmeldung P 2 645 656.4 beschriebenen Methode erfolgt) mit 3-Nitrobenzolsulfonsäurechlorid und anschließend katalytischer Hydrierung hergestellt wurde, wurde mit 100 ml Chloroform und 3,2 ml Pyridin angeschlämmt und mit 4,4 g 3-(N-Methyl-N-cyanäthyl-aminobenzol-azo)-4-chlorbenzolsulfonsäurechlorid versetzt. Der Ansatz wurde 10 Stunden bei 40°C gerührt. Anschließend wurde der Ansatz gekühlt und unter Zugabe von 350 ml Methanol 30 Minuten gerührt. Der ausfallende Niederschlag wurde abgesaugt, mit Methanol gewaschen und getrocknet.6.48 g of the compound of the following formula

by the reaction of 2- (2,4-ditert.-pentylphenoxybutylamino-carbonyl) -3-amino-5-methoxy-indole (which is prepared by a method described in German patent application P 2 645 656.4) with 3-nitrobenzenesulfonyl chloride and then catalytic hydrogenation was prepared, was suspended with 100 ml of chloroform and 3.2 ml of pyridine and mixed with 4.4 g of 3- (N-methyl-N-cyanoethyl-aminobenzene-azo) -4-chlorobenzenesulfonic acid chloride. The mixture was stirred at 40 ° C for 10 hours. The mixture was then cooled and stirred for 30 minutes with the addition of 350 ml of methanol. The precipitate was filtered off, washed with methanol and dried.

Yield 6.1 g; Mp: 244-246 ° (Z).

The other coloring compounds of the present invention can also be prepared in an analogous manner.

The diffusing dyes split off from the color-providing compounds according to the invention are used for the absorption measurement and light-fastness test (see Example 2). The preparation of the dye released from compound 2 is described here as an example.

• 1,73 g 3-Aminobenzolsulfonsäureamid wurden in 40 ml Chloroform und 3,2 ml Pyridin angeschlämmt und mit 4,4 g 3-(4-N-Methyl-N-cyanäthyl-aminobenzol-azo)-4-chlorbenzolsulfonsäure- chlorid (90%ig) versetzt. Es wurde 4 h bei 40°C nachgerührt. Es wurden weitere 0,4 g Sulfochlorid zugesetzt und erneut 3 Stunden bei 40°C gerührt. Der ausfallende Neiderschlag wurde abgesaugt und mit Chloroform gewaschen und getrocknet. Das Nutschgut wurde mit 2 n Salzsäure verrührt, abgesaugt, mit 2 n Salzsäure und H₂0 gewaschen. Anschließend wurde die Substanz durch mehrfaches Extrahieren mit Essigester und Einengen der Mutterlauge gereinigt. Ausbeute 3,5; Fp.: 120-122° (Z).

Dye from compound 2:

• 1.73 g of 3-aminobenzenesulfonic acid amide were suspended in 40 ml of chloroform and 3.2 ml of pyridine and mixed with 4.4 g of 3- (4-N-methyl-N-cyanoethyl-aminobenzene-azo) -4-chlorobenzenesulfonic acid chloride (90 %) offset. The mixture was stirred at 40 ° C for 4 h. A further 0.4 g of sulfochloride were added and the mixture was stirred again at 40 ° C. for 3 hours. The precipitated envy was sucked off and washed with chloroform and dried. The filter cake was stirred with 2N hydrochloric acid, suction filtered, washed with 2N hydrochloric acid and H ₂ 0. The substance was then purified by extracting several times with ethyl acetate and concentrating the mother liquor. Yield 3.5; Mp .: 120-122 ° (Z).

The compounds according to the invention are colored yellow. They are incorporated into the casting solutions for the layers of the photographic material using one of the usual methods. The amount of coloring compound used per liter of casting solution varies within relatively wide limits, the most favorable concentration being determined on the basis of simple experiments. For example, 5 to 80 g, preferably 20 to 40 g, of coloring compound are used per liter of casting solution.

The association between diffusion-resistant coloring compound and silver halide required to achieve the desired effect can be produced, for example, by introducing the diffusion-resistant compounds into the casting solutions from aqueous-alkaline solutions using existing water-solubilizing groups. The non-diffusing coloring compounds can also be incorporated into the layers by one of the known emulsification processes. Such methods are described, for example, in English Patents 791 219 and 1 099 414 to 1 099 417. It is also possible to prepare aqueous dispersions of the color compounds and to add them to the respective casting solutions. Here, aqueous slurries of the coloring compound are finely ground, for example by intensive stirring with the addition of sharp-edged sand or by using ultrasound. In a further embodiment, it may be desirable, for example, to store the coloring compounds together with silver halide and optionally developer substances in the form of so-called microcapsules, two or more differently sensitized light-sensitive silver halide emulsions and the corresponding diffusion-resistant compounds in a single layer after the Type of the so-called mixed grain emulsions can be combined, as is described, for example, in US Pat. No. 2,698,794. The non-diffusing coloring compounds can be accommodated in a light-sensitive layer itself or in a neighboring layer. For example, the red-sensitive layer is associated with a compound that cleaves off a cyan dye, the green-sensitive layer is associated with a compound that cleaves off a purple dye, and the blue-sensitive layer is associated with a coloring compound that cleaves off a yellow dye according to the invention.

• Hydrochinon
• N-Methylaminophenol
• 1-Phenyl-3-pyrazolidon
• 1-Phenyt-4,4-dimethyt-3-pyrazotidon
• 1-Phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidon
• Aminophenole
• N,N-Diäthyl-p-phenylendiamin
• N-Äthyl-N-hydroxyäthyl-p-phenylendiamin
• N-Athyl-N-co-sulfobutyl-p-phenylendiamin
• 3-Methyl-N,N-diäthyl-p-phenylendiamin
• N,N,N',N'-Tetraalkyl-p-phenylendiamine wie Tetramethyl-p-phenylendiamin, 1,4-Bis-pyrrolidinobenzol, Reduktone.

By "assignment" and "assigned" it is understood that the mutual arrangement of silver halide emulsion and coloring compound is of such a nature that an interaction between them is possible which results in a bitternal agreement between the silver image formed (in the case of negative-working coloring compounds) and the undeveloped one Silver halide (in the case of positive-working coloring compounds) on the one hand and imagewise distribution of the releasing, diffusing dye on the other hand. In this case, the assigned coloring compound is expediently incorporated into the silver halide emulsion itself or into a layer adjacent to the silver halide emulsion layer, this adjacent layer preferably (viewed in the direction of the light incident during exposure) behind the silver halide emulsion layer lies. The color-imparting compounds according to the invention are oxidized imagewise during the development of the silver image of developer oxidation products and are then subject to a cleavage reaction under the influence of the developer or activator alkali, in which the dye residues are generally released in diffusing form. The usual photographic developer compounds are suitable for development insofar as they are able to oxidize the color-imparting compounds according to the invention in oxidized form. Examples of suitable developers are as follows:

• Hydroquinone
• N-methylaminophenol
• 1-phenyl-3-pyrazolidone
• 1-phenyte-4,4-dimethyl-3-pyrazotidone
• 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone
• Aminophenols
• N, N-diethyl-p-phenylenediamine
• N-ethyl-N-hydroxyethyl-p-phenylenediamine
• N-ethyl-N-co-sulfobutyl-p-phenylenediamine
• 3-methyl-N, N-diethyl-p-phenylenediamine
• N, N, N ', N'-tetraalkyl-p-phenylenediamines such as tetramethyl-p-phenylenediamine, 1,4-bis-pyrrolidinobenzene, reductones.

It should be pointed out in particular that the selection of developer substances in the process according to the invention is not limited to color developers, but that conventional black white developers can also be used, which is to be regarded as an advantage because of the lower tendency to discoloration of the latter. The developers can already be contained in the layers of the color photographic material, where they are activated by the alkaline activator liquid, or in the alkaline processing liquid or paste. Since the coloring compounds according to the invention themselves have developer properties, the use of auxiliary developer compounds can be dispensed with in individual cases. In this case, the coloring compound is immediately oxidized by developable silver halide.

If the imagewise distribution of the diffusing dye released during development matches the developed silver image, as is the case with the coloring compounds of the type as described in DT-OSen 2 242 762, 2, 505 248 and also DT-OS 1 772 929, the use of direct positive silver halide emulsions or, if conventional negative emulsions are used, the use of a suitable reversal process is required to generate positive colored transfer images. In the case of the coloring compounds of the last-mentioned DT-OS, the diffusing dyes are not released as a result of an alkali cleavage, but rather as a result of an intramolecular displacement reaction with ring closure. The dyes released also do not have a free sulfaemoyl group like the dyes split off from the coloring compounds used according to the invention, but a sulfinic acid group. However, the invention is in no way limited to those coloring compounds in which the cleavage is carried out by alkali.

Such a reversal process is available in the silver salt diffusion process. The photographic reversal using the silver salt diffusion process to produce positive color images using conventional color couplers is described, for example, in US Pat. No. 2,763,800. By exchanging the color couplers for the coloring compounds mentioned, a light-sensitive element is obtained which is suitable for the dye diffusion transfer process. Such a photosensitive element has, for example, at least one combination of a photosensitive silver halide emulsion layer and a binder layer assigned to it, which contains development nuclei for physical development and a coloring compound.

During the development, the exposed portion of the silver halide is chemically developed in the light-sensitive silver halide emulsion layer; the unexposed portion is transferred by means of a silver halide solvent into the binder layer containing the associated development nuclei and is physically developed there. If a developer is used for the physical development, which is able to release a diffusing dye in oxidized form as a result of a reaction with the coloring compound present in this layer, then an imagewise distribution of diffusing dyes occurs, which is applied to an image receiving layer can be transferred and form a positive colored image there.

When reversed using compounds which release imagewise development inhibitors, the photosensitive element consists of at least one layer combination of a photosensitive silver halide emulsion layer and a second, unexposed, developable emulsion layer which contains the coloring compound. The light-sensitive silver halide emulsion layer is developed, for example, with color developers in the presence of certain compounds which release development-inhibiting substances on reaction with oxidized color developers. The development-inhibiting substances, which are imagewise set free in the light-sensitive layer, diffuse into the neighboring, unexposed, developable emulsion layer and visually inhibit development there. The uninhibited (positive) portions of the unexposed developable emulsion layer are developed by the remaining developer, whose oxidation products then react with the non-diffusing coloring compounds according to the invention with the release of diffusing dyes, which are transferred imagewise to the image-receiving element. Suitable compounds which split off development-inhibiting substances on reaction with color developer oxidation products are, for example, the known DIR couplers (DIR = development inhibitor releasing), which are color couplers which contain a cleavable inhibitor residue in the coupling point. Such DIR couplers are described, for example, in US Pat. No. 3,227,554.

Another group of compounds which release development-inhibiting substances on reaction with color developer oxidation products is described in US Pat. No. 3,632,345. These are not color couplers. Accordingly, no dyes are formed when the development-inhibiting substances are released. According to DT-PS 1 229 389, suitable substituted, non-diffusing hydroquinone compounds can finally be used in such a process, which are oxidized to the corresponding quinones in the reaction with developer oxidation products and thereby aspirate development-inhibiting mercaptans.

In principle, all direct positive silver halide emulsions are suitable as direct positive silver halide emulsions which, with simple development, produce a positive silver image and a corresponding image-wise distribution of developer oxidation products. For example, those silver halide emulsions are suitable in which a veil that can be developed has been generated by exposure or by chemical treatment, which veil is destroyed imagewise under certain conditions during the imagewise exposure. The fog remains in the unexposed areas, so that a directly positive silver image is obtained in the subsequent development, and in accordance therewith an imagewise distribution of diffusing dye if the colorant compound according to the invention is assigned to the directly positive silver halide emulsion.

vorzugsweise kein Silberbild, oder nur eines mit sehr geringer Dichte ergeben, während bei Verwendung eines Innenkeimentwicklers der folgenden Zusammensetzung:

ein Silberbild mit ausreichender Dichte entsteht.Another group of direct positive silver halide emulsions which are preferably used according to the present invention comprises the so-called unveiled direct positive silver halide emulsions, which have a photosensitivity predominantly inside the silver halide grains. When these emulsions are exposed imagewise, a latent image is formed predominantly inside the silver halide grains. However, the development of such unveiled, directly positive silver halide emulsions is carried out under hazing conditions, a veil being produced predominantly at the unexposed areas and a positive silver image being developed during the development. The unveiled direct positive silver halide emulsions are characterized in that exposed samples are developed using a typical surface developer of the following composition:

preferably no silver image, or only one with very low density, while using an inner winder of the following composition:

a silver image with sufficient density is created.

The selective fogging of the imagewise exposed, unveiled direct positive emulsions can be carried out before or during development by treatment with a fogging agent. Suitable fogging agents are reducing agents such as hydrazine or substituted hydrazines. Reference is made, for example, to US Pat. No. 3,227,552, the obscuring agent can also be stored diffusion-resistant.

Unveiled direct-positive emulsions are, for example, those which have defects in the interior of the silver halide grains (US Pat. No. 2,592,250) or silver halide emulsions with a layered grain structure (DT-OS 2,308,239).

When coloring compounds according to the invention are used with a non-diffusing oxidizable carrier residue of the type described in DT-OSs 2 402 900 and 2 543 902, i.e. a carrier residue which is only split off by alkali in the non-oxidized form, while in the oxidized form the removal is difficult or prevented, of course no direct positive emulsions and no reversal processes are required to produce positive transfer images, but conventional negative emulsions are sufficient.

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 and 568,687, also polyamines, such as diethylenetriamine, or aminomethanesulfinic acid derivatives, e.g. be used 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 with 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 spectrally sensitized, e.g. by the usual mono- or polymethine dyes, such as acidic or basic cyanines, hemicyanines, streptocyanines, merocyanines, oxonols, hemioxonols, styryl dyes or other, also trinuclear or polynuclear methine dyes, for example rhodacyanines or neocyanines. Such sensitizers are described, for example, in F. M. Hamer's work "The Cyanine Dyes and Related Compounds" (1964) Interscience Publishers John Wiley and Sons.

The emulsions can contain the usual stabilizers, e.g. homeopolar or salt-like compounds of mercury with aromatic or heterocyclic rings, such as mercaptotriazoles, simple mercury salts, sulfonium mercury double salts and other mercury compounds. Also suitable as stabilizers are azaindenes, preferably tetra- or penta-azaindenes, in particular those which are substituted by hydroxyl or amino groups. Such connections are in the Birr article. Z. Wiss. Phot. 47, 2-27 (1952). Other suitable stabilizers include heterocyclic mercapto compounds, e.g. Phenyl mercaptotetrazole, quaternary benzothiazole derivatives, benzotriazole and the like.

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. Examples of synthetic binders are polyvinyl alcohol, partially saponified polyvinyl acetate, polyvinyl pyrrolidone and the like. The layers can be cured in the customary manner, for example using formaldehyde or halogen-substituted aldehydes which contain a carboxyl group, such as mucobromic acid, diketones, methanesulfonic acid esters, dialdehydes.

To carry out the dye diffusion transfer process according to the present invention, a photosensitive element is used which contains one or more silver halide emulsion layers and the associated non-diffusing, coloring compounds, and an image-receiving element in which the desired color image is obtained by means of the imagewise transferred, diffusing dyes is produced. This requires that there be firm contact between the photosensitive member and the image-receiving member for at least a finite period within the development time, so that the imagewise distribution of diffusing dyes generated in the photosensitive member as a result of development can be transferred to the image-receiving member. The contact can be made after development has started or it can have been made before development begins. The latter is the case, for example, if a material is used to carry out the dye diffusion transfer process in which the light-sensitive element and the image-receiving element form an integral unit, also referred to below as mono-sheet material, which continues to exist even after the development process has ended; that is, a separation of the photosensitive element from the image receiving element is also after color transfer not provided. Such an embodiment is described, for example, in DT-OS 2 019 430.

• 1) einen transparenten Schichtträger
• 2) eine Bildempfangsschicht
• 3) eine lichtundurchlässige Schicht
• 4) ein lichtempfindliches Element mit mindestens einer lichtempfindlichen Silberhalogenidemulsionsschicht und mindestens einer dieser zugeordneten nichtdiffundierenden, farbgebenden Verbindung
• 5) eine Verzögerungsschicht
• 6) eine saure Polymerschicht
• 7) einen transparenten Schichtträger

A monosheet material suitable for carrying out the dye diffusion transfer process according to the present invention has, for example, the following layer elements:

• 1) a transparent substrate
• 2) an image receiving layer
• 3) an opaque layer
• 4) a light-sensitive element with at least one light-sensitive silver halide emulsion layer and at least one non-diffusing, color-imparting compound associated therewith
• 5) a retardation layer
• 6) an acidic polymer layer
• 7) a transparent substrate

The mono-sheet material can be composed in such a way that two different parts are produced separately from one another, namely the light-sensitive part (layer elements 1-4) and the cover sheet (layer elements 5-7), which are then placed on one another on the layer side and connected to one another, if appropriate using spacer strips so that a space for receiving a precisely measured amount of a working fluid is formed between the two parts. The layer elements 5 and 6, which together form the neutralization system, can also be arranged, albeit in the opposite order, between the layer support and the image-receiving layer of the light-sensitive part.

Means may be provided to introduce a working fluid between the photosensitive member and the cover sheet, e.g. in the form of a laterally arranged, splitable container which, when subjected to mechanical forces, pours its contents between two adjacent layers of the mono-sheet material.

An essential part of the photographic material according to the present invention is the photosensitive element which, in the case of a single dye transfer process, contains a photosensitive silver halide emulsion layer and associated with it, a non-diffusing coloring compound. The non-diffusing compound can be located in a layer adjacent to the silver halide emulsion layer, or in the silver halide emulsion layer itself, in the latter case the color of the image dye is preferably selected such that the predominant absorption range of the coloring compound does not match the predominant sensitivity range of the silver halide emulsion layer. To produce multicolored transfer images in true-to-life colors, however, the photosensitive element contains three such assignments of coloring compound and light-sensitive silver halide emulsion layer, the absorption range of the coloring compound generally matching the range of spectral sensitivity of the associated silver halide emulsion layer. The prerequisite for the highest possible sensitivity, however, is that the color-providing combination is arranged in a separate binder layer (seen in the direction of the light incident during the exposure) behind the silver halide emulsion layer.

• Blauempfindliche Silberhalogenidemulsionsschicht
• Schicht mit nichtdiffundierender, einen diffundierenden Gelbfarbstoff freisetzender Verbindung. Trennschicht,
• Grünsensibilisierte Silberhalogenidemulsionsschicht,
• Schicht mit nichtdiffundierender, einen diffundierenden Purpurfarbstoff freisetzender Verbindung Trennschicht
• Rotsensibilisierte Silberhalogenidemulsionsschicht,

The developer oxidation products formed during the development of a silver halide emulsion may of course only have an effect on the assigned coloring compound. Separating layers are therefore generally present in the photosensitive element, which effectively prevent the diffusion of the developer oxidation products into other unassigned layers. These separating layers can contain, for example, suitable substances which react with the developer oxidation products, for example non-diffusing hydroquinone derivatives, or, if the developer is a color developer substance, non-diffusing color couplers. In a preferred embodiment, the photosensitive element therefore has the following structure (from top to bottom):

• Blue sensitive silver halide emulsion layer
• Layer with non-diffusing compound which releases a diffusing yellow dye. Interface,
• Green-sensitized silver halide emulsion layer,
• Layer with non-diffusing, separating layer releasing a diffusing purple dye
• Red-sensitized silver halide emulsion layer,

Layer with a non-doping compound that releases a diffusing cyan dye.

Of course, the silver halide emulsion layers can also be arranged in a different order, but the assigned layers must also be interchanged with the coloring systems so that the assignment is retained.

The opaque layer arranged under the photosensitive element is permeable to aqueous alkaline treatment solutions and thus to the diffusing dyes. It has two main functions.

First, it is used after the development in the original photosensitive Element remaining image silver, as well as the color compounds remaining as color negative, so that when viewed through the transparent support of the light-sensitive part, only the positive color transfer image is visible. Secondly, it closes the light-sensitive element in a light-tight manner on the side of the image-receiving layer (downward). The latter is particularly important if, after exposure, the mono-sheet material is still brought into contact with the alkaline processing compound in the camera, then is to be pulled out of the camera and developed outside the camera.

Layers with sufficient opacity, but sufficient permeability for diffusing dyes can, for example, with suspensions of inorganic or organic dark, preferably black pigments, for example with suspensions of carbon black in suitable binders e.g. be made in gelatin solutions. In general, 0.5 to 2 g thick layers containing 10 to 90% by weight (based on the total dry weight) of carbon black in gelatin are sufficient in order to ensure sufficient exclusion of light during development. The particle size of the pigments used is relatively uncritical as long as it does not significantly exceed µ, 5 µ.

In addition to the black pigment layer, the opaque layer preferably also comprises a white pigment layer arranged underneath. This has the task of covering the black layer and creating a white background for the picture. All white pigments are suitable for this, provided that their opacity is sufficiently high for layers that are not too large. Examples include barium sulfate, oxides of zinc, titanium, silicon, aluminum and zircon, and also barium stearate or kaolin. Titanium dioxide is preferred as the white pigment. The same information applies to the binder, the concentration and the particle size as for the black pigments. The thickness of the white pigment layer can be varied depending on the desired whiteness of the substrate. Thicknesses between 5-20 f1 are preferably used.

Instead of the opaque layer, means for producing such an opaque layer may also be arranged in the monosheet material according to the present invention between the photosensitive element and the image-receiving layer, e.g. in the form of a laterally arranged container with a working fluid containing an opacifying agent (pigment) which, when subjected to mechanical forces, pours its contents between the layers mentioned, so that such a pigment layer forms there.

The image-receiving layer essentially consists of a binder which contains dye mordants for fixing the diffusing dyes.

Long-chain quaternary ammonium or phosphonium compounds or ternary sulfonium compounds, e.g. those as described in US Pat. Nos. 3,271,147 and 3,271,148. Furthermore, certain metal salts and their hydroxides, which form poorly soluble compounds with the acid dyes, can also be used. The dye mordants are dispersed in the receiving layer in one of the usual hydrophilic binders, e.g. in gelatin, polyvinylpyrrolidone, wholly or partially hydrolyzed cellulose residues and the like. Of course, some binders can also act as mordants, e.g. Copolymers or polymer mixtures of vinyl alcohol and N-vinylpyrrolidone as described, for example, in DT-AS 1 130 284, furthermore those which are polymers of nitrogen-containing quaternary bases, e.g. Polymers of N-methyl-2-vinylpyridine, as described, for example, in US Pat. No. 2,484,430. Further usable binders are, for example, gyanylhydrazone derivatives of acylstyrene polymers, as described, for example, in DT-OS 2 009 498. In general, however, the last-mentioned pickling binders other binders, for example Add gelatin.

As the transparent layer support for the monosheet material according to the invention, the usual transparent support materials used in photographic practice, e.g. Films made of cellulose esters, polyethylene terephthalate, polycarbonate or other film-forming polymers can be used.

The alkaline processing composition sets a relatively high pH in the light-sensitive material (about 11 to 14), which triggers the development and the imagewise dye diffusion. It has been shown that at this high pH the dyes and thus the images obtained are not particularly stable. It is therefore necessary that the material is made almost neutral or weakly acidic after development is complete. This can be achieved in a known manner in that the material additionally contains an acidic polymer layer which is only gradually accessible to the alkaline processing composition in the course of development. An acidic polymer layer is understood to mean a binder layer which contains polymeric compounds with acid groups, preferably sulfo or carboxyl groups. These acidic groups react with the cations of the processing mass to form salt and lower the pH of the mass. Of course, the polymeric compounds and thus the acidic groups are embedded in the layer mentioned in a diffusion-resistant manner. In many cases, the acidic polymers are derivatives of cellulose or derivatives of polyvinyl compounds, but other polymeric compounds can also be used. Examples of useful acidic polymers are: cellulose derivatives with a free carboxyl group, for example cellulose dicarboxylic acid semiesters with a free carboxyl group, such as cellulose acetathydrogenphthalat, Celluloseacetathydrogenglutarat, Athylcelluloseacetathydrogensuccinat, Celluloseacetathydrogensuccinathydrogenphthalat, ethers and esters of cellulose, which are modified with other dicarboxylic acid anhydrides or sulfonic acid anhydrides, such as o-sulfobenzoic anhydride, carboxymethylcellulose, furthermore polystyrene, polyvinyl, Polyvinylacetathydrogenphthalat, polyacrylic acid, acetals of polyvinyl alcohol with aldehydes by carboxy - or sulfo groups are substituted, such as o-, m- or p-benzaldehyde sulfonic acid or carboxylic acid, partially esterified ethylene-maleic anhydride copolymers, partially esterified methyl vinyl ether-maleic anhydride copolymers and the like.

The acidic polymer layer must contain sufficient acid groups in order to lower the pH of the processing mass from the beginning 11 to 14 to such an extent that the material is finally almost neutral or slightly acidic (pH 5 to 8).

The time delay of the lowering of the pH value is achieved in a known manner in that the acidic polymer layer is coated with a so-called delay layer. This delay layer is an alkali-permeable layer, which preferably consists of an alkali-inert polymer, for example of polyvinyl alcohol or a partially acetalized polyvinyl alcohol. By a suitable choice of the thickness and the composition of this delay layer, the time delay of the lowering of the pH value can be adjusted in the desired manner. A brake layer with polymers of a novel permeability behavior is described, for example, in DT-OS 2 455 762.

Neutralization systems, which are understood to mean a combination of an acidic polymer layer and a retardation layer, are described, for example, in DT-PS 1 285 310. Such layer combinations can be present in the material according to the invention, for example in the light-sensitive part between the transparent layer support and the image-receiving layer. Another possibility is to arrange the neutralization system from the acidic polymer layer and a delay layer on the cover sheet. Of course, these two layers must be arranged in such a sequence that the alkali of the processing composition must first penetrate the retardation layer in order to get into the acidic polymer layer.

The dye diffusion transfer process according to the invention can advantageously be carried out in or by means of a suitable self-developing camera. This can e.g. be provided with devices which, after exposure of the photosensitive element, make it possible to distribute a working solution between the latter and the cover sheet and to cover the photosensitive material in an opaque manner. Such a camera is preferably provided with two nip rollers mounted against one another, between which the mono-sheet material is pulled out, the laterally arranged containers being split up and releasing their contents between the layers of the mono-sheet material.

. Since the light-sensitive element is protected from unwanted exposure by opaque layers on both sides after passing through the nip rollers, the exposed material can be pulled out of the camera immediately after development has started.

To process the imagewise exposed monosheet material, the photosensitive element is brought into contact with the aqueous alkaline working solution. In this case, the imagewise exposed silver halide emulsion layers are developed in the presence of the developer compound, an imagewise distribution of oxidation products of the developer compound being produced in accordance with the positive silver image thereby formed, which oxidizes the assigned coloring compound, whereupon these react the diffusing dye with the alkali of the activator splits off. The aqueous alkaline working solution can contain viscosity-increasing additives, e.g. Hydroxyethyl cellulose. Development accelerators, stabilizers, silver salt solvents, fogging agents, antioxidants and other additives can also be contained in the working solution in a known manner.

example 1

• 1) Eine Beizschicht aus 6 g eines Polyurethans aus 4,4-Diphenyimethandiisocyanat, N-Äthyldi- äthanolamin und Epichlorhydrin und 6,0 g Gelatine.
• 2) Eine Reflektionsschicht aus 24 g Tio₂ und 2,4 g Gelatine.
• 3) Eine Rußschicht aus 1,9 g Ruß und 2 g Gelatine.
• 4) Eine Farbstoffschicht aus 0,5 g der Verbindung I (blaugrün) und 0,9 g Gelatine.
• 5) Eine rot sensibilisierte Emulsionsschicht mit einer unverschleierten direkt-positiv arbeitenden Silberchloridbromidemulsion, Silberauftrag 2,6 g, Gelatine 1,3 g und 0,04 g N-[a-(2,4-ditert,- amylphenoxy)-acetyl]-N'-phenyl-hydrazin als Schleiermittel.
• 6) Eine Sperrschicht aus 0,5 g Octadecylhydrochinonsulfosäure und 1,3 g Gelatine.
• 7) Eine Farbstoffschicht aus 0,5 g der Verbindung II (purpur) und 0,9 g Gelatine.
• 8) Eine grün sensibilisierte Emulsionsschicht mit einer unverschleierten direkt positiv arbeitenden Silberchloridbromidemulsion, Silberauftrag 2,5 g, Gelatine 1,28 g und 0,04 g N-[a-(2,4-ditert.-amyl- phenoxy)-acetyl]-N'-phenyl-hydrazin als Schleiermittel.
• 9) Eine Sperrschicht identisch mit Schicht 6).
• 10) Eine 'Farbstoffschicht aus 0,65 g der Verbindung III (gelb) und 1,0 g Gelatine.
• 11) Eine blau sensibilisierte Emulsionsschicht mit einer unverschleierten direkt-positiv arbeitenden Silberchloridbromidemulsion, Silberauftrag 2,7 g, Gelatine 1,4 g und 0,04 g N-[a-(2,4-ditert.- amylphenoxy)-acetyl]-N'-phenyl-hydrazin als Schleiermittel.
• 12) Eine Schutzschicht aus 0,8 g Gelatine und 0,8 g einer Verbindung der folgenden Formel (Härtungsmittel):
  
• 13) Ein transparentes Deckblatt aus Polyäthylenterephthalat mit einer Neutralisationsschicht und einer Verzögerungsschicht.

A light-sensitive element of a photographic material according to the invention was produced by successively applying the following layers on a transparent support made of polyester film. The quantities given relate in each case to 1 m ^2.

• 1) A pickling layer made of 6 g of a polyurethane made of 4,4-diphenyimethane diisocyanate, N-ethyldiethanolamine and epichlorohydrin and 6.0 g of gelatin.
• 2) A reflective layer made of 24 g Tio ₂ and 2.4 g gelatin.
• 3) A layer of soot consisting of 1.9 g of soot and 2 g of gelatin.
• 4) A dye layer consisting of 0.5 g of compound I (blue-green) and 0.9 g of gelatin.
• 5) A red-sensitized emulsion layer with an unveiled direct-positive working silver chloride bromide emulsion, silver application 2.6 g, gelatin 1.3 g and 0.04 g N- [a- (2,4-ditert, - amylphenoxy) -acetyl] - N'-phenyl-hydrazine as a fogging agent.
• 6) A barrier layer consisting of 0.5 g octadecyl hydroquinone sulfonic acid and 1.3 g gelatin.
• 7) A dye layer of 0.5 g of compound II (purple) and 0.9 g of gelatin.
• 8) A green sensitized emulsion layer with an unveiled direct positive working Silver chloride bromide emulsion, silver application 2.5 g, gelatin 1.28 g and 0.04 g of N- [a- (2,4-ditert.-amyl-phenoxy) -acetyl] -N'-phenyl-hydrazine as foggant.
• 9) A barrier layer identical to layer 6).
• 10) A dye layer of 0.65 g of compound III (yellow) and 1.0 g of gelatin.
• 11) A blue-sensitized emulsion layer with an unveiled direct-positive working silver chloride bromide emulsion, application of silver 2.7 g, gelatin 1.4 g and 0.04 g of N- [a- (2,4-ditert.- amylphenoxy) -acetyl] - N'-phenyl-hydrazine as a fogging agent.
• 12) A protective layer of 0.8 g of gelatin and 0.8 g of a compound of the following formula (hardening agent):
  
• 13) A transparent polyethylene terephthalate cover sheet with a neutralization layer and a retardation layer.

• 50 g KOH
• 10 ml Benzylalkohol
• 3 g Benzotriazol
• 10 g Natriumsulfit
• 6,0 g 1-Phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidon
• 0,1 g Hydrochinon
• 34 g Hydroxyäthylcellulose

aufgefüllt auf 1000 ml Wasser.After exposure through a step wedge, the light-sensitive element was covered with the transparent cover sheet on the layer side. For the development of the imagewise exposed photosensitive element, a splitable container with an alkaline working liquid of the following composition was used

• 50 g KOH
• 10 ml of benzyl alcohol
• 3 g benzotriazole
• 10 g sodium sulfite
• 6.0 g of 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone
• 0.1 g hydroquinone
• 34 g of hydroxyethyl cellulose

made up to 1000 ml of water.

The image set was passed through a pair of squeeze rollers, the developer paste being distributed between the photosensitive element and the cover sheet. The paste thickness was 110 µ. To adjust this, spacer strips of appropriate thickness were attached to the side of the image between the photosensitive element and the cover sheet.

Further photosensitive elements were produced in the same manner with the only exception that the dye III of the layer was replaced by one of the compounds No. 3 to No. 7 according to the invention. After the same processing, direct-positive multicolored images of the original (film sets B ― F) also resulted.

After a development time of 1 hour, the Dmax and Dmin values of the image-receiving layers listed in the following table were determined using a reflection densitometer using a blue filter.

It can be seen from the results obtained that higher color densities can be achieved with the colorant compounds of the present invention.

Formula appendix to example 1

The lightfastness test and the absorption measurement were carried out on the transfer dyes themselves, which are released from the coloring compounds in diffusing form.

The dye to be investigated was pickled by continuously immersing a transparent layer support with a pickling layer which corresponds to layer 1 from Example 1 in an aqueous dye solution. It was then washed and dried for 2 minutes.

The absorption measurement was carried out with a spectrophotometer.

To test the light-fastness, a strip of the materials obtained with the dyes to be compared was attached to a TiO ₂ base and exposed to radiation of 1.10 ⁵ 1 x (approx. 20 ° C; approx. 20 ° C) in the Hanau Xenotest device for 24 hours. 60% relative humidity). The residual density remaining after the irradiation was calculated according to the following equation.

The measurement was carried out in the density range (before exposure) from 1.0 to 1.5.

The residual densities obtained are shown in the following table.

Claims (2)

1. A photographic dye diffusion transfer process for the production of coloured images, in which a photographic material having at least one light-sensitive silver halide emulsion layer and a non-diffusible dye-providing compound associated with this layer is exposed imagewise and developed with a silver halide developer, a diffusible dye being released imagewise from the non-diffusible dye-providing compound by the alkali of the developer and transferred to an image receptor layer, characterised in that the non-diffusible dye-providing compound used is a compound corresponding to the following formula I:

in which

A¹ represents an oxidizable organic carrier residue in the o-, m- or p-position to the azo group, which carrier residue contains a group which confers diffusion resistance and which carrier residue may be attached through a connecting member X, from which carrier residue, either in its oxidized form or in its unoxidized form, at least part thereof together with the group which confers diffusion resistance is split off by developer alkali under the conditions of photographic development and a diffusible azo dye is at the same time released imagewise;

A² represents an oxidizable organic carrier residue containing a group which confers diffusion resistance and which carrier residue may be attached through a connecting member X, which carrier residue is attached in the ortho- or meta-position, either directly or through one of the substituents R² and R³, to the phenyl ring which carries the cyanoalkylamino group, from which carrier residue, either in the oxidized form or in the unoxidized form, at least part thereof together with the group which confers diffusion resistance is split off by developer alkali under the conditions of photographic development and at the same time a diffusible azo dye is released imagewise;

A3 represents an oxidizable organic carrier residue which may be attached through a connecting member X and contains a group which confers diffusion resistance, which carrier residue is attached to the substituent R' and from which carrier residue, either in the oxidized form or in the unoxidized form, at least a part thereof together with the group which confers diffusion resistance is split off by developer alkali under the conditions of photographic development and a diffusible azo dye is at the same time released imagewise;

R' represents hydrogen, alkyl with 1 to 5 C atoms, aralkyl or aryl;

R², R³, R⁵ and R⁶, which may be the same or different, each represents one of the groups mentioned under R¹, sulpho, -COOR⁴, halogen, trihalogenmethyl, acylamino, acyloxy, carbamoyl, sulphamoyl, -OR⁴, -SR⁴, -SOR4, ―SO₂―R⁴, wherein R⁴ has one of the meanings specified for R¹, -NO₂ or -CN;

X represents a bivalent connecting member of the formula ―R―(L)_p―(R)_q―, in which R represents an alkylene group with 1 to 6 C atoms or an optionally substituted phenylene group and the two groups R may be the same or different;

L represents -0-, -CO-, -CONR⁷, ―SO₂NR⁷, ―O―CO―NR⁷, -S-, -S0₂- or -SO- in which R⁷ = hydrogen or alkyl;

p = 0 or 1,

q = 0 or 1, and q = 1 if p = 1

I, m and n each represents 0 or 1 such that I + m + n = 1;

r represents 2 or 3; and

s represents 0 or 1.

2. The process as claimed in claim 1, characterised in that the non-diffusible dye-providing compound used is a compound of the following formula II:

in which

R¹ represents hydrogen or alkyl with 1 to 5 C atoms

R², R³, R⁵ and R⁸ which may be the same or different, represent hydrogen, chlorine, methyl, methoxy, acylamino, or nitro;

A4 represents a group corresponding to one of the following formulae substituted with at least one group which confers diffusion resistance:

in which

Z represents a group which confers diffusion resistance;

Y' represents a group required to complete a benzene or naphthalene ring;

Y" represents a group required to complete a condensed, carbocyclic or heterocyclic ring,, which may be substituted and

R⁸ represents hydrogen, alkyl, alkoxy, aryl, a heterocyclic group, carboxyl, carbamoyl or alkoxycarbonyl;

X represents a bivalent connecting member corresponding to the formula ―R―(L)_p―(R)_q―, in which

R represents an alkylene group with 1 to 6 C atoms or an optionally substituted phenylene group and the two groups R may be the same or different;

L represents -0-, -CO-, -CONR⁷, ―SO₂NR₇ ―O―CO―NR⁷ -S- ―SO₂― or -SO- in which R = hydrogen or alkyl;

p = 0 or 1;

q = 0 or 1; and q = 1 if p = 1

r = 2 or 3 and

s = 0 or 1.