GB2035589A - Development restrainer precursors - Google Patents

Abstract

The invention relates to photographic processes involving development restraint to photographic elements containing development restrainer precursors and to such precursors per se. Development restrainer precursors hitherto available, in general, hydrolyse too rapidly in strongly alkaline solution for satisfactory performance in colour diffusion transfer processes of reproduction. The invention provides a class of such precursors which hydrolyse at a more useful rate represented by formula I:- <IMAGE> wherein Z completes a heterocyclic ring, which may be substituted, and each of R<1> and R<2> is a substituent on the N atom or together complete a heterocyclic ring containing the N atom which may be substituted. Preferably the heterocyclic ring represented by Z in the compound contains 2 N atoms. Preferably, the ring in the compound is benzotriazole and such compounds are preferably of formula:- <IMAGE> wherein: R<1> and R<2> each represent a substituted or unsubstituted alicyclic, aliphatic, aromatic or heterocyclic moiety or, taken together with the nitrogen to which they are attached, form a heterocyclic ring; and R<3>, R<4>, R<5> and R<6> each represent hydrogen, nitro, alkyl, halogen, carbamoyl, sulphamoyl, RCONH- or RSO2NH-, wherein R is alkyl or aryl. These compounds are new.

Description

SPECIFICATION Development restrainer precursors for photographic elements This invention relates to photography, and more particularly to photographic elements and assemblages for colour diffusion transfer photography wherein certain azole compounds having an alkalihydrolyzable, N,N-disubstituted carbamoyl group are employed as development restrainer precursors and of which those containing a benzotriazole group are new.

U.S. Patent 4,076,529 of Fleckenstein eta, issued February 28, 1978, describes various colour image transfer elements which employ nondiffusible, redox dye-releasing compounds which are alkalicleavable upon oxidation to release a diffusible colour-providing moiety Development restrainers or precursors thereof are usually employed in such elements to try to progressively slow down the rate of development during the latter stages of the process without adversely affecting the initial development rate.

Various blocked antifoggants and development restrainers are disclosed in Japanese Patent 586,882 and U.S. Patents3,364,028,3,575,699 and 3,649,267.

These references do not disclose the compounds useful in our invention, however.

Research Disclosure article 13118, March 1975, discloses various blocked benzotriazoles useful as development restrainers in colour diffusion transfer elements. Such compounds have been found to become hydrolyzed by the alkaline processing composition too rapidly, however. In some instances, hydrolysis is essentially complete in ten seconds or less. When that happens, the initial development rate is adversely affected.

The compounds employed in our invention hydrolyze at a much slower rate than those of the prior art. In a 0.1 M aqueous sodium hyroxide solution, our compounds typically have a half-life of ten seconds to several minutes. These compounds have the desired property of progressively restraining development without adversely affecting the initial development rate.

According to the present invention there is provided a process of photographic reproduction in which an imagewise exposed light-sensitive silver halide layer is developed and the development restrained by a heterocyclic compound having a nitrogen atom in the heterocyclic ring which compound has been formed after the commencement of development by hydrolysis of a precursor for the heterocyclic compound having an alkalihydrolysable N-substituted carbamoyl group on said heterocyclic nitrogen atom, characterised in that said N-substituted carbamoyl group is a di-N,Nsubstituted carbamoyl group.

Preferably, the heterocyclic ring contains two nitrogen atoms.

A photographic element in accordance with our invention comprises a support having thereon at least one photo-sensitive silver halide emulsion layer having associated therewith a dye imageproviding material, and where in the element contains an azole compound comprising an azole ring having at least two nitrogen atoms, said compound having an alkali-hydrolyzable, N,N-disubstituted carbamoyl group on one ofthetwo nitrogen atoms.

In a preferred embodiment of our invention, the azole compound which is employed has the following formula: wherein:

R' and R2 each represent a substituted or unsubstituted alicyclic, aliphatic, aromatic or heterocyclic moiety, or may be taken together with the nitrogen to which they are attached to form a heterocyclic ring; and Z represents the atoms necessary to complete an azole ring containing at least two nitrogen atoms.

In the above formula, R' and RZ can each be a substituted or unsubstituted alicyclic group, such as cycloalkyl of 3 to 20 carbon atoms; e.g., cyclopropyl, cyclohexyl, cyclodecyl or cyclooctadecyl; an aliphatic group, such as a straight or branched chain alkyl group of 1 to 20 carbon atoms, including aralkyl and aryloxyalkyl, e.g., methyl, ethyl, isopropyl, butyl, hydroxyethyl, octyl, pentyl, dodecyl, pentadecyl, octadecyl, benzyl, furfuryl, or phenoxypropyl; an aromatic group, such as aryl of 6 to 20 carbon atoms, including alkaryl and alkoxyaryl, e.g., phenyl, naphthyl, methylphenyl, Cmethoxyphenyl, p-sulphamoylphenyl, p-dodecylphenyl, butoxyphenyl; or a heterocyclic moiety containing from 5 to 20 non-metallic atoms, such as thienyl, pyridyl, or pyrimidyl; or may be taken together with the nitrogen to which they are'attached to form a heterocyclic ring, such as morpholine, piperidine, pyrrolidine, piperazine, etc. In a preferred embodiment of the invention, each R' and R2 is a substituted or unsubstituted alkyl or aryl group, as described above. In a more preferred embodiment, each R' and R2 is ethyl, ethyl#phenyl, 4-methoxy-phenyl or -(CH2)10-COOC2H5, or are taken together to complete a morpholine or piperidine ring.

As stated above, Z represents the atoms necessary to complete an azole ring containing at least two nitrogen atoms. In a preferred embodiment of the invention, Z represents the atoms necessary to complete a benzotriazole, triazole, tetrazole, indazole or benzimidazole ring. Such rings may be substituted with lower alkyl groups, halogen atoms, nitro groups, etc.

In another preferred embodiment of the invention new compounds are used represented by formula I wherein Z represents the atoms necessary to complete a benzotriazole ring. In a more preferred embodiment, the benzotriazole compound can have either of the following formulas:

wherein: R' and R2 are as defined above; and R3, R4, RS and RB each represent hydrogen, nitro, lower alkyl (including substituted alkyl) of 1 to 6 car bon atoms, such as methyl, ethyl, propyl, isopropyl, hexyl, carboxymethyl, etc; halogen, such as chloro, bromo, etc; carbamoyl, sulphamoyl, RCONH- or RSO2NH-, wherein R is a lower alkyl group of 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, hexyl, carboxymethyl, etc, or an aryl group of 6 to 10 carbon atoms, such as phenyl, tolyl, etc.

Preferably each of R3, R4 and RB is H and R5 is CH3.

Typical compounds included within the scope of the above formula include the following:

The development restrainer precursors employed in this invention may be incorporated into any layer of the photographic element described above. They may be incorporated into the silver halide emulsion layer, the dye image-providing material layer, inter layers, etc. They may be employed in any amount suitableforthe intended purpose. In general, good results are obtained when the compounds are employed in a concentration range of from 0.05 to 1.5 grams persquare metre of element. The compounds may be incorporated as solutions, as fine particulate dispersionsror dissolved in droplets of a highboiling solvent.

The dye image-providing material useful in our invention can be positive- or negative-working, and can be initiallymobile or immobile in the photo- graphic element during processing with an alkaline composition. Examples of initially mobile, positive-working dye image-providing materials useful in our invention are described in U.S. Patents 2,983,606; 3,536,739; 3,705,184; 3,482,972; 2,756,142; 3,880,658 and 3,854,985. Examples of negative-working dye image-providing materials useful in our invention include conventional couplers which react with oxidized aromatic primary amino color developing agents to produce or release a dye such as those described, for example, in U.S Patent 3,227,550 and Canadian Patent 602,607. In a preferred embodiment of our invention, the dye image-providing material is a ballasted, redox-dyereleasing (RDR) compound.Such compounds are well know to those skilled in the art and are, generally speaking, compounds which will redox with oxidized developing agent or electron transfer agent to release a dye, such as by alkaline hydrolysis, or prevent the release of dye, such as by intramolecular nucleophilic displacement. Such nondiffusible RDR's can be positive-working compounds, as described in U.S. Patent 3,980,479, British Patent 1,464,104 and U.S. Patent 4,139,379, issued February is, 1979. Such nondiffusible RDR's can also be negative-working compounds, as described in U.S.Patents 3,728,113 of Becker et al; 3,725,062 of Anderson and Lum; 3,698,897 of Gompf and Lum; 3,628,952 of Puschel et al; 3,443,939 and 3,443,940 of Bloom et al; 4,053,312 of Fleckenstein; 4,076,529 of Fleckenstein et al; 4,055,428 of Koyama et al; German Patents 2,505,248 and 2,729,820; Research Disclosure 15157, November, 1976; and Research Disclosure 15654, April, 1977. In a more preferred embodiment of our invention, the nondiffusible RDR's are ballasted p-sulphonamidonaphthol compounds, each of which has a color-providing moiety attached thereto through a sulfonamido group which is alkali-cleavabte upon oxidation.

A process for producing a photographic image in colouraccording to our invention comprises: treating an imagewise-exposed photographic element, as described above, with an alkaline processing composition in the presence of a silver halide developing agent to effect development of each exposed silver halide emulsion layer, whereby: (a) an imagewise distribution of dye is formed as a function of the development of the silver halide emulsion layer; and (b) at least a portion of the imagewise distribution of the dye diffuses out of the element, such as to a dye image-receiving layer.

The above process is performed in the presence of the development restrainer precursor described above. During processing, the carbamoyl substituent is split off of the azole compound to provide the development restrainer, i.e., a compound accord- in to formula I above is hydrolyzed by the aqueous alkaline processing composition to form the development restrainer:

Z being defined as above, which may be ionized in the composition.

The position of the H atom in the above formula is not necessarily the same as that of the -CONR'R2 in formula I. Thus, in some compounds the hydrolys able-CONR1R2 group blocks the development restrainer action but is not at the position which becomes active on hydrolysis. Compounds 15 and 16 are examples of such compounds. It will be appreciated that, after processing the photographic elements described above, there remains in the elements, after transfer has taken place, an imagewise distribution of dye in addition to developed silver. A colour image comprising residual nondiffusible compound may be obtained in these elements if the residual silver and silver halide are removed in any conventional manner well known to those skilled in the photographic art, such as a bleach bath followed by a fix bath, a bleach-fix bath, etc.The imagewise distribution of dye may also diffuse out of these elements into these baths, if desired, rather than to an image-receiving element.

The photographic element in the above-described process can be treated with an alkaline processing composition to effect or initiate development in any manner. One method for applying processing composition is by use of a rupturable container or pod which contains the composition. In general, the processing composition employed in this invention contains the developing agent for development, although the composition could also be solely an alkaline solution where the developer is incorporated in the photographic element, the imagereceiving element or the process sheet, in which case the alkaline solution serves to activate the incorporated developer.

A photographic film unit or assemblage in accordance with this invention is adapted to be processed by an alkaline processing composition, and comprises: 1) a photographic element as described above; and 2) a dye image-receiving layer.

In this embodiment, the processing composition may be inserted into the film unit, such as by interjecting processing solution with communicating members similar to hypodermic syringes which are attached either to a camera or camera cartridge. The processing composition may also be applied by means of a swab or by dipping in a bath, if so desired. The development restrainer precursors described above may be incorporated into the photographic element, as described above, or may be incorporated into the dye image-receiving layer or any layer associated therewith.

In another embodiment of the invention, the assemblage itself contains the alkaline processing composition and means containing same for discharge within the film unit, such as a rupturable containerwhich is adapted to be positioned during processing of the film unit so that a compressive force applied to the container by pressure-applying members, such as would be found in a camera designed for in-camera processing, will effect a discharge of the container's contents within the film unit.

The dye image-receiving layer in the abovedescribed film unit can be located on a separate support adapted to be superposed on the photographic element after exposure thereof. Such image-receiving elements are generally disclosed, for example, in U.S. Patent 3,362,819. When the means for discharging the processing composition is a rupturable container, it is usually positioned in relation to the photographic element and the image-receiving element so that a compressive force applied to the container by pressure-applying members, such as would be found in a typical camera used for in-camera processing, will effect a discharge of the container's contents between the image-receiving element and the outermost layer of the photographic element. After processing, the dye.

image-receiving element is separated from the photographic element.

The dye image-receiving layer in the abovedescribed film unit can also be located integral with the photographic element between the support and the lowermost photosensitive silver halide emulsion layer. One useful format for integral receivernegative photographic elements is disclosed in Belgian Patent 757,960. In such an embodiment, the support for the photographic element is transparent and is coated with an image-receiving layer, a substantially opaque light-reflective layer, e.g. TiO2, and then the photosensitive layer or layers described above. After exposure of the photographic element, a rupturable container containing an alkaline processing composition and an opaque process sheet are brought into superposed position.Pressureapplying members in the camera rupture the container and spread processing composition over the photographic element as the film unit is withdrawn from the camera. The processing composition develops each exposed silver halide emulsion layer, and dye images, formed as a function of develop ment, diffuse to the image-receiving layerto provide a positive, right-reading image which is viewed through the transparent support on the opaque reflecting layer background. For other details concern- ing the format of this particular integral film unit, reference is made to the above-mentioned Belgian Patent 757,860.

Another format for integral negative-receiver photographic elements in which the present invention can be employed is disclosed in Belgian Patent 757,959. In this embodiment, the support for the photographic element is transparent and is coated with the image-receiving layer, a substantially opa que, light-reflective layer and the photosensitive layer or layers described above. A rupturable con tainer, containing an alkaline processing composi tion and an opacifier, is positioned between the top layer and a transparent cover sheet which has thereon a neutralizing layer and a timing layer. The film unit is placed in a camera, exposed through the transparent cover sheet and then passed through a pair of pressure-applying members in the camera as it is being removed therefrom.The pressure applying members rupture the container and spread processing composition and opacifier over the nega tive portion of the film unit to render it light insensitive. The processing composition develops each silver halide layer and dye images, formed as a result of development, diffuse to the image receiving layer to provide a positive, right-reading image which is viewed through the transparent sup port on the opaque reflecting layer background. For further details concerning the format of this particular integral film unit, reference is made to the above-mentioned Belgian Patent 757,959.

Still other useful integral formats in which this invention can be employed are described in U.S.

Patents 3,415,644; 3,415,645; 3,415,646; 3,647,437; and 3,635,707. In most of these formats, a photosensitive silver halide emulsion is coated on an opaque support, and a dye image-receiving layer is located on a separate transparent support superposed over the layer outermost from the opaque support. In addition, this transparent support also preferably contains a neutralizing layer and a timing layer underneath the dye image-receiving layer.

Another embodiment of the invention uses the image-reversing technique disclosed in British Patent 904,364, page 19, lines 1 through 41. In this process, the dye-releasing compounds are used in combination with physical development nuclei in a nuclei layer contiguous to the photosensitive silver halide negative emulsion layer.. The film unit contains a silver halide solvent, preferably india rupturable container with the alkaline, processing composition.

The film unit or assembly ofthe present invention may be used to produce positive images in single- or multi-colour. In a three-coloursystem, each silver halide emulsion layer of the film assembly will have associated therewith a dye image-providing material which possesses a predominant spectral absorptifan within the region of the visible spectrum to which said silver halide emulsion is sensitive, i.e., the blue-sensitive silver halide emulsion layer will have a yellow dye image-providing material associated therewith, the green-sensitive silver halide emulsion layer will have a magenta dye image-providing mat- erial associated therewith, and the red-sensitive silver halide emulsion layer will have a cyan dye image-providing material associated therewith.The dye image-providing material associated with each silver halide emulsion layer may be contained either in the silver halide emulsion layer itself or in a layer contiguous to the silver halide emulsion layer, i.e., the dye image-providing material may be coated in a separate layer underneath the silver halide emulsion layer with respect to the exposure direction.

The concentration of the dye image-providing material that is employed in the present invention may be varied over a wide range, depending upon the particularcompound employed and the results desired. For example, the dye image-providing mat erial may be coated in a layer at a concentration of 0.1 to 3 g/m2. The dye image-providing material may be dispersed in a hydrophilic film-forming natural material or synthetic polymer, such as gelatin, polyvinyl alcohol,- etc, which is adapted to be perme ated by aqueous alkaline processing composition.

A variety of silver halide developing agents can be employed in this invention. Specific examples of developers or ETA compounds which can be emp loyed in this invention include hydroquinone com pounds, such as hydroquinone, 2,5 dichlorohydroquinone,2-chlorohydroquinone and the like; aminophenol compounds, such as 4-aminophenol,N-methylaminophenol, N,N dimethylarninophenol,3-methyl-4-aminophenol, 3,S-dibromoaminophenol and the like; catechol compounds, such as catechol, 4-cyclohexylcatechol, 3-methoxycatechoP,4-(N-octadecylamino)catechol and the like; phenylenediamine compounds, such as N,N -#diethyl -p - phenylenediamine,3 - methyl - N,N - diethyl -p - phenylenediamine, 3 - methoxy - N - ethyl N - ethoxy -p - phenylenediamine, N,N,N'N' - tet ramethyl -p - phenylenediamine and the like. In highly preferred embodiments, the ETA is a 3 pyrazolidinone compound, such as 1 - phenyl - 3 pyrazolidinone (Phenidone) Registered Trade Mark, 1 - phenyl - 4,4 - dimethyl - 3 - pyrazolidinone (Dimezone), 4 - hydroxymethyl - 4 - methyl - 1 phenyl - 3 - pyrazolidinone, 4 - hydroxymethyl - 4 methyl - 1 -p - tolyl - 3 - pyrazolidinone, 4 - hydrox- ymethyl-4- methyl - 1 - (3, 4- dimethylphenyl)-3- pyrazolidinone, 1 -m-tolyl-3-pyrazolidinone, -p - tolyl - 3 - pyrazolidinone,1 - phenyl - 4 - methyl - 3 pyrazolidinone,1 - phenyl - 5 - methyl - 3 pyrazolidinone,1 - phenyl - 4,4- dihydroxymethyl - 3 - pyrazolidinone, 1,4 - dimethyl - 3 - pyrazolidinone, 4 4 -methyl-3- pyrazolidinone, 4,4- dimethyl - 3 pyrazolidinone, 1 - (3 - chlorophenyl) - 4 - methyl - 3 pyrazolidinone, 1 - (4 - chlorophenyl) - 4 - methyl - 3 pyrazolidinone, 1 - (3 - chlorophenyl) - 3 - pyrazolidinone, 1 - (4 - chlorophenyl) - 3 pyrazolidinone, t - (4 - tolyl) - 4 - methyl - 3 pyrazolidinone, 1 - (2 - tolyl) - 4 - methyl - 3 pyrazolidinone, 1 - (4 - tolyl) - 3 - pyrazolidinone, 1 (3 - tolyl) - 3 - pyrazolidinone, 1 - (3 - tolyl) - 4,4 dimethyl - 3 - pyrazolidinone,1 - (2 - trifluoroethyl) 4,4 - dimethyl - 3 - pyrazolidinone,5 - methyl - 3 pyrazolidinone, and the like. A combination of differ ent ETA's, such as those disclosed in U.S. Patent 3,039,869, can also be employed. Such developing agents can be employed in the liquid processing composition or may be contained, at least in part, in any layer or layers of the photographic element or film unitto be activated by the alkaline processing composition, such as in the silver halide emulsion layers, the dye image-providing material layers, interlayers, image-receiving layer, etc.

In using dye image-providing materials in the invention which produce diffusible dye images as a function of development, either conventional negative-working or direct-positive silver halide emulsions may be employed. If the silver halide emulsion employed is a direct-positive silver halide emulsion, such as an internal-image emulsion designed for use in the internal image reversal process, or a fogged, direct-positive emulsion such as a solarizing emulsion, which is developable in unexposed areas, a positive image can be obtained on the dye image-receiving layer by using ballasted, redox, dye-releasers. After exposure of the film unit, the alkaline processing composition permeates the various layers to initiate development of the exposed photosensitive silver halide emulsion layers.The developing agent present in the film unit develops each of the silver halide emulsion layers in the unexposed areas (since the silver halide emulsions are direct-positive ones), thus causing the developing agent to become oxidized imagewise corresponding to the unexposed areas of the direct-positive silver halide emulsion layers. The oxidized developing agent then cross-oxidizes the dye-releasing compounds and the oxidized form of the compounds then undergoes a base-catalyzed reaction to release the dyes imagewise as a function of the imagewise exposure of each of the silver halide emulsion layers. At least a portion of the imagewise distributions of diffusible dyes diffuse to the imagereceiving layer to form a positive image of the original subject.After being contacted by the alkaline processing composition, a pH-lowering layer in the film unit or image-receiving unit lowers the pH of the film unit or image receiver to stabilize the image.

Internal-image silver halide emulsions useful in this invention are described more fully in the November 1976 edition of Research Disclosure, pages 76 through 79, the disclosure of which is hereby incorporated by reference.

The various silver halide emulsion layers of a colour film assembly employed in this invention can be disposed in the usual order, i.e., the blue-sensitive silver halide emulsion layer first with respect to the exposure side, followed by the green-sensitive and red-sensitive silver halide emulsion layers. If desired, a yellow dye layer or a yellow colloidal silver layer can be present between the bluesensitive and green-sensitive silver halide emulsion layers for absorbing or filtering blue radiation that may be transmitted through the blue-sensitive layer.

If desired, the selectively sensitized silver halide emulsion layers can be disposed in a different order, e.g., the blue-sensitive layer first with respect to the exposure side, followed by the red-sensitive and green-sensitive layers.

The rupturable container employed in certain embodiments of this invention can be of the type disclosed in U.S. Patents 2,543,181; 2,643,886; 2,653,732; 2,723,051; 3,056,492; 3,056,491 and 3,152,515. In general, such containers comprise a rectangular sheet of fluid- and air- impervious mater- ial folded longitudinally upon itself to form two walls which are sealed to one another along their longitudinal and end margins to form a cavity in which processing solution is contained.

Generally speaking, except where noted otherwise, the silver halide emulsion layers employed in the invention comprise photosensitive silver halide dispersed in gelatin and are about 0.6 to 6 microns in thickness; the dye image-providing materials are dispersed in an aqueous alkaline solution-permeable polymeric binder, such as gelatin, as a separate layer about 0.2 to 7 microns in thickness; and the alkaline solution-permeable polymeric interlayers, e.g., gelatin, are about 0.2 to 5 microns in thickness. Of course, these thicknesses are approximate only and can be modified according to the product desired.

Any material can be employed as the imagereceiving layer in this invention as long as the desired function of mordanting or otherwise fixing the dye images is obtained. The particular material chosen will, of course, depend upon the dye to be mordanted. Suitable materials are disclosed on pages 80 through 82 of the November 1976 edition of Research Disclosure, the disclosure of which is hereby incorporated by reference.

Use of a pH-lowering material in the film units of this invention will usually increase the stability of the transferred image. Generally, the pH-lowering material will effect a reduction in the pH of the image layer from about 13 or 14 to at least 11 and preferably 5 to 8 within a short time after imbibition. Suitable materials and their functions are disclosed on pages 22 and 23 of the July 1974 edition of Research Disclosure, and pages 35 through 37 of the July 1975 edition of Research Disclosure, the disclosures of which are hereby incorporated by reference.

Atimingorinertspacerlayercan be employed in the practice of this invention over the pH-lowering layer which "times" or controls the pH reduction as a function of the rate at which the alkaline composition -diffuses through the inert spacer layer. Examples of such timing layers and their functions are disclosed in the Research Disclosure articles mentioned in the paragraph above concerning pH-lowering layers.

The alkaline processing composition employed in this invention is the conventional aqueous solution of an alkaline material, e.g., alkali metal hydroxides or carbonates such as sodium hydroxide, sodium carbonate or an amine such as diethylamine, preferably possessing a pH in excess of 11, and optionally containing a developing agent as described previously. Suitable materials and addenda frequently added to such compositions are disclosed on pages 79 and 80 of the November 1976 edition of Research Disclosure, the disclosure of which is hereby incorporated by reference.

The alkaline solution-permeable, substantially opaque, light-reflective layer employed in certain em- bodiments of photographic film units used in this invention are described more fully in the November 1976 edition of Research Disclosure, page 82, the disclosure of which is hereby incorporated by reference.

The supports for the photographic elements used in this invention can be any material, as long as it does not deleteriously affect the photographic properties of the film unit and is dimensionally stable.

Typical flexible sheet materials are described on page 85 of the November 1976 edition of Research Disclosure, the disclosure of which is hereby incor porated by reference.

While the invention has been described with refer ence to layers of silver halide emulsions and dye image-providing materials, dotwise coating, such as would be obtained using a gravure printing techni que, could also be employed. In this technique, small dots of blue-, green- and red-sensitive emulsions have associated therewith, respectively, dots of yel low, magenta and cyan colour-providing sub stances. After development, the transferred dyes would tend to fuse together into a continuoustone.

The silver halide emulsions useful in this inzen- tion, both negative-working and direct-positiveones, are well known to those skilled in the art and are described in Research Disclosure, Volume 176, December 1978, Item 17643, pages 22 and 23, "Emulsion preparation and types"; they may be chemically and spectrally sensitized as described on page 23, "Chemical sensitization", and "Spectral sensitization and desensitization", of the above article; they can be protected against the production of fog and can be stabilized against loss of sensitivity during keeping by employing the materials described on pages 24 and 25, "Antifoggants and stabilizers", of the above article; they can contain hardeners and coating aids as described on page 26, "Hardeners", and pages 26 and 27, "Coating aids", of the above article; they and other layers in the photographic elements used in this invention can contain plasticizers, vehicles and filter dyes described on page 27, "Plasticizers and lubricants", page 26, "Vehicles and vehicle extenders", and pages 25 and 26, "Absorbing and scattering materials", of the above article; they and other layers in the photographic elements used in this invention may contain addenda which are incorporated by using the procedures described on page 27, "Methods of addition", of the above article; and they can be coated and dried by using the various techniques described on pages 27 and 28, "Coating and drying procedures", of the above article, the disclosures of which are hereby incorporated by reference.

The term "nondiffusing" used herein has the meaning commonly applied to the term in photography and denotes materials that for all practical purposes do not migrate or wander through organic colloid layers, such as gelatin, in the photographic elements of the invention in an alkaline meditirn and preferably when processed in a medium having a pH of 11 or greater. The same meaning is to be attached to the term "immobile". The term "diffusible"' as applied to the materials of this invention hasthe converse meaning and denotes materials having the property of diffusing effectively through the colloid layers of the photographic elements in an alkaline medium. "Mobile" has the same meaning as "diffus- ible".

The term "associated therewith" as used herein is intended to mean that the materials can be in either the same or different layers so long as the materials are accessible to one another.

The following examples are provided to further illustrate the invention.

Example 1~Preparation of Compound 1 Compound 1:1- (N - Ethyl - N - phenylcarbamoyl)- 5(6) - methylbenzotriazole

a) N- Ethyl - N - phenylcarbamoyl chloride (B) This was prepared by the method of Carpino and Gowecke (L. A. Carpino and S. Gowecke,J. Org.

Chem., 29, 2824, 1964), in 60 percent yield, m.p. 44 to 450C (uncorr.).

b) 1- (N - Ethyl - N - phenylcarbamoyl) - 5- methyl- benzotriazole (1) 5-Methylbenzotriazole (C) (13.3 g, 0.1 mole) was suspended in triethylamine (100 ml) and Nethyl-N-phenylcarbamoyl chloride (B) (18.35 g, 0.1 mole) was added in small portions, with stirring. The resultant mixture was heated under reflux for 2 hours, cooled, and the solvent was removed under reduced pressure. The residue was taken up in water (200 ml) and dichloromethane (200 ml) and the organic layer was separated.This was washed with dilute hydrochloric acid (3 molar, 1 x 200 ml), dried (magnesium sulphate) and the solvent was removed to leave an oil which crystallized from a cyclohex ane:petroleum ether (b.p. 40 to 60 C) mixture (1:1.5 v/v) to give the product (1) as a colorless solid (21.72 g, 78 percent), m.p. 42 to 43 C (uncorr.).

C16H1sN4o Requires: C, 68.55; H, 5.75; N,19.99 / Found: C, 68.11; H, 5.81; N, 19.86% Example 2~Preparation of Compound 2 Compounds 2:1 - (N - Morpholinocarbonyl) -5(6) - methylbenzotriazole

a) Morpnollnocarbonylchloride (E) This was prepared by the method of Boon (W. R.

Boon, J.C.S., 307, 1947), in 66 percent yield, b.p. 105 to 107 C/7.5 mm.

b) 1 - Morphollnocarbonyl -5- methylbenzotriazole 2) Compound 2 was prepared by treating 5-methylbenzotriazole (C) (8.89 g, 67 m.mole) with morpholinocarbamoyl chloride (E) (lOg, 67 m.mole) in a manner similar to that described in the preparation of (1). The product was crystallized from methanol (100 ml). Yield, 13.2 g, 81 percent, m.p. 81 to 820C (uncorr.).

C12H14N402 Requires: C, 58.52; H, 5.73; N,22.75% Found: C, 58.33; H, 5.73; N, 22.97% Other examples which were prepared via the method used for Compound 2 include: Example 3--Preparation of Compound 3 Compound 3: 1- Piperidinocarbonyl - 5(6) - methyl- benzotriazole This was prepared in 73 percent yield, m.p. 49 to 50 C (uncorr.) from petroleum ether (b.p. 40 to 60 C).

C,3H16N4O Requires: C, 63.91; H, 6.60; N,22.94% Found: C, 63.53; H, 6.60; N, 22.87% Example 4-Preparation of Compound 4 Compound4: 1 -(N, N-diphenylcarbamoyl)-5(6)methylbenzotriazole This was prepared in 76 percent yield, m.p. 132 to 1330C (uncorr., from methanol).

C20H1,N4ORequirns: C, 73.15; H,4.91; N, 17.06% Found: C, 72.85; H, 5.03; N, 17.28% Example 5--Preparation of Compound 8 Compound 8: 1 -Morpholinocarbonyl-5, 6- dimeth ylbenzotriazole This was prepared in 61 percent yield, m.p. 1910C (uncorr., from methanol).

C13H16N4O2 Requires: C, 59.99; H, 6.20; N, 21.53% Found:C,59.82;H,6.20;N,22.27% Example 6--Preparation of Compound 10 Compound 10: 1 Morpholinocarbonyl -4, 6(5, 7) - dimethylbenzotriazole This was prepared in 64 percent yield, m.p. 11 5'C (uncorr., from methanol).

C13H1,N4O2 Requires: C, 59.99; H, 6.20; N, 21.53% Found: C, 59.10; H, 6.12; N, 21.77% Example 7~Preparation of Compound 12 Compound 12: 1- Morpholinocarbonyl - 5, 6 - dichlorobenzotriazole This was prepared in 64 percent yield, m.p. 1450C (uncorr., from methanol).

C11 H10Cl2N4O2 Requires: C, 43.87; H, 3.35; Cl,23.54; N, 18.61% Found: C, 43.75; H, 3.40; Cl,24.76; N, 18.80% Example 8~Preparation of Compound 15 Compound 15:2 - Morpholinocarbonyl - 4,5, 6, 7 - tetrachlorobenzotriazole This was prepared in 50 percent yield, m.p. 194'C (uncorr., from methanol).

C11H8Cl4N4O2 Requires: C, 35.71; H, 2.18; Cl,38.32; N, 15.14% Found: C, 35.64; H, 2.17; Cl,38.00; N, 15.50% Example 9--Preparation of Compound 6 Compound 6: Ethyl 11- [ N - (5(6) - methyl - 1- benzotriazolylcarbonyl) - N - ethyl]-aminoundecanoate This was prepared in 88 percent yield as an oil after chromatographic purification.

C23H36N4O3 Requires: C, 66.32; H,8.71; N,13.45% Found: C, 66.26; H, 8.62; N,13.55% Other compounds which were prepared in two stages via the method used for compound 1 include: Example 1#Preparation of Compound 5 Compound 5: 1- (N - Ethyl - N -(4 - methoxyphenyl) - 5(6) -methylbenzotriazole This was prepared in 67 percent yield, m.p. 750C (uncorr., from cyclohexane:petroleum ether) (40 to 60'C) (1:4).

C17H18N4O, Requires: C, 65.79; H, 5.85; N, 18.05 Found: C, 65.45; H, 5.92; N, 17.93 Example 11~Preparation of Compound 9 Compound 9:1 - (N - Ethyl - N - phenylcarbamoyl) 5, 6 - dimethyl - benzotriazole This was prepared in 81 percent yield, m.p. 1360C (unc#orr., from methanol).

C17H18N4O Requires: C, 69.37; H, 6.16; N, 19.04% Found: C, 69.12; H, 6.21; N, 19.28% Example 12~Preparation of Compound 11 Compound 11: 1 (N -(N-Ethyl-N-phenylcarbamoyl)- 4, 6(5, 7) - dimethyl - benzotriazole This was prepared in 71 percent yield, m.p. 90'C (uncorr., from methanol).

C1,H18N4O Requires: C, 69.37; H, 6.16; N, 19.04% Found: C, 69.33; H, 6.20; N,19.48% Example 13~Preparation of Compound 13 Compound 13: 1 (N -(N-Ethyl-N-phenylcarbamoyl)- 5, 6 - dichlorobenzotriazole This was prepared in 88 percent yield, m.p. 1200C (uncorr., from cyclohexane).

C15H12Cl2N4O Requires: C, 53.75; H, 3.61; Cl,21.15; N, 16.72% Found: C, 53.79; H,3.74; Cl,21.18; N, 16.92% Example 14--Preparation of Compound 16 Compound 16:2 - (N - Ethyl - N - phenylcarbamoyl) 4, 5, 6, 7- tetrachlorobenzotriazole This was prepared in 86 percent yield, m.p. 1570C (uncorr., from cyclohexane).

C15H10Cl4N4O Requires: C, 44.59; H, 2.49; Cl,35.09; N, 13.87 % Found: C, 44.65; H, 2.50; Cl,35.18; N,14.15% Example 15~Preparation of Compound 7 Compound 7: Ethyl 11- [1 - (N - Ethyl - N- phenyl- carbamoyl) -6 - benzotriazolecarbonamidojunde canoate This was prepared in 87 percent yield as a white oily solid after chromatographic purification.

C29H3,N5O4 Requires: C, 66.28; H, 7.48; N, 13.32% Found: C, 66.77; H, 7.54; N, 13.42% Example 164reparation of Compound 14 Compound 14:5,6 - Dichloro - 1- dimethylcarbamoylbenzotriazole In 100 ml ofdrytetrahydrofuran, 1.2 g of sodium hydride is suspended. To this mixture, a solution of 9.4 g of 5,6-dichlorobenzotriazole in 250 ml of tet rahydrofuran is added with vigorous stirring. After it is stirred at room temperature for 30 minutes, 5.4 of N,N-dimethylcarbamoyl chloride is added, and the reaction mixture is refluxedfor 15 minutes, then allowed to gradually come to room temperature. The sodium chloride salt formed is removed; the solution is treated with charcoal and filtered.The solvent is evaporated to yield a white, solid residue. Recrystallization from aqueous methanol yields 6.7 g (51.9 percent) of colorless solid; m.p. 120 to 1230C.

C9HBCl#N4O Requires: C,41.7; H, 3.1; N, 21.7 Found: C, 42.2; H, 3.3; N, 21.6 Example 17 The rates of hydrolysis of the development restrainer precursors in alkaline solution were estimated as follows: A silver-silver chloride electrode was freshly prepared by electrolysis of a clean silver rod in 0.5 M aqueous potassium chloride solution. This electrode, together with a standard calomel reference electrode, was connected to a pH meter whose out put was recorded on a chart recorder. The electrodes were immersed in a stirred solution at room temperature of composition: 10 percent v/v ethanol, 90 per- cent water, 0.1 M sodium hydroxide, and 0.01 M.

potassium chloride. The volume of the solution was 50 ml. A solution of development restrainer precursor (2 ml of 0.4 M solution in ethanol) was added rapidly from a syringe, and the resulting perturbation of the electrical potential given by the electrode pair was recorded as a function of time. When 5-methylbenzotriazole was added, the time taken for the potential to reach 60 percent of the difference between the final and initial readings (which should approximately correspond to 50 percent adsorption of the benzotriazole at the electrode) was about 3 second. This is taken as the response time ofthe measuring system.

In this way, estimates were made of the t1/2 value (time for half the added development restrainer pre cursorto be hydrolyzed to the development restrainer) for the various compounds of the inven tion. The values found are given in Table t. The letter I by a value indicates that the compound was largely insoluble in the solution, giving a greater t1/2 value than would otherwise be the case.

TABLE I Compound Hydrolysis t1/2 No. (seconds) 1 > 3001 2 15 3 65 4 > 300 1 5 > 3001 61 > 3001 7 > 3001 8 11 9 ,3001 10 9 11 > 3001 12 301 13 > 3001 15 1801 16 > 6001 Example 78-Photographic Test i) Preparation ofreceiversheets a) A receiver sheet was prepared by coating an aqueous solution (pH 6.5) onto polyethylene-coated paper to give the following coated layer (concentrations are in grams per square meter unless otherwise stated): gelatin 2.2 polyvinylimidazole (10 percent quaternized with 2-chloroethanol) 2.2 4-hydroxymethyl-4-methyl-1 phenyl-3-pyrazolidone 0.22 piperidine hydrochloride 0.09 formaldehyde 0.04 This receiver a) constitutes a control.

b) Another receiver was prepared as a), but with the addition of a fine dispersion of prior art compound [ 1 - cyclo - hexylcarbamoyl - 5(6) - methylben zotriazolej (0.27) dissolved in droplets of diethyl lauramide (O.79).

c) Another receiver was prepared similar to a), but with the addition of a solution in acetone of Compound 1 (0.48) of the invention.

d) Another receiver was prepared similar to a), but with the addition of a solution, in tetrahydrofu ran, of Compound 2 (0.32) of the invention ii) Preparation of Photosensitive Element A photosensitive element was prepared by coating the following layers in the order recited on a poly(ethylene terephthalate) film support. Quantities are parenthetically given in grams per square meter unless otherwise stated.

(1) red-sensitive, negative-working, 15:85 silver chlorobromideemulsion (silver 0.59, gelatin 1.35) and cyan RDR A (0.44) dispersed in 1,4 - cyclohexylenedimethylene- bis- (2- ethylhexanoate) (0.22); (2) interlayer of gelatin (1.35) and 2,5-di-sec dodecyl-hydroquinone (0.97); (3) magenta RDR B (0.44) dispersed in 1,4 - cyc lohexylene - dimethylene- bis(2 - ethylhexanoate) (0.22) and gelatin (1.35); (4) green-sensitive, negative-working, 15:85 silver chlorobromide emulsion (silver 0.95, gelatin 1.35); (5) interlayer of gelatin (1.35) and 2, 5 - di - sec F dodecyl - hydroquinone (0.83); (6) yellow RDR C (1.12) dispersed in 1,4 - cyclohexylene- dimethylene- bis(2 - ethylhexanoate) (.56), gelatin (1.43), and bis(vinylsulphonylmethyl) ether (0.11); (7) blue-sensitive, negative-working, 15::85 silver chiorobromide emulsion (silver 1.18, gelatin 1.35) and 2,5 - di -sec - dodecylhydroquinone (0.1); and (8) gelatin (1.35) and copolv [ styrene(N, N dimethyl - N - benzyl - N - 3 - maleimidop ropyl)ammonium chloridel (0.1).

iii) Testing ofReceiver Sheets Portions of the photosensitive element of ii) were exposed to a sensitometric light source. They were soaked in the activator solution described below at 300C for 15 seconds, then withdrawn and squeegeed into intimate face-to-face contact with a portion of the receiver sheet of i).

Activator Solution potassium hydroxide 37 9 benzyl alcohol 10 ml 11-aminoundecanoic acid 2 9 6-aminohexanoic acid 15 9 5-methylbenzotriazole 1 9 water to 1 litre The coatings were peeled apart after 2.5 and 5 minutes process time. A negative dye image was visible on the receiving sheets. The reflection densities in unexposed (din) and in fully exposed (may) areas were read through red, green and blue filters. The results are given in Table II. A signifies the difference between the density at 5 minutes and the density at 2.5 minutes.

TABLE II Dmin Dmax Development Time Receiver Restrainer (minutes) Red Green Blue Red Green Blue (a) None 2.5 0.11 0.15 0.18 2.51 2.19 2.78 control 5 0.18 0.20 0.30 2.57 2.24 3.20 A 0.07 0.05 0.12 0.08 0.05 0.42 (b) prior art 2.5 0.12 0.16 0.19 2.08 1.78 238 control compound 5 0.16 Q.18 0.24 2.68 2.06 2.74 A 0.04 0.02 0.05 0.60 0.28 0.36 (c) Compound 1 2.5 0.13 0.17 0.16 2.29 2.09 2.17 5 0.16 0.20 0.21 2.56 2.17 2.41 A @.03 0.03 0.05 0.27 (y.08 0.24 (d) Compound 2 2.5 0.12 0.15 0.16 2.56 2.20 2.34 5 0.18 0.18 0.21 3.16 2.42 2.87 A 0.06 0.03 0.05 0.60 0.28 0.53 The results show that all of the development restrainer precursors limited the growth of minimum density compared with control (a). However, the rapid release of the prior art compound resulted in undue suppression of the red and green Dmax at the shorter time of lamination. The compounds of the invention, however, gave similar control of Dmin without so much suppression of Dmax.

Example 1SPhotographic Test i) Preparation ofReceiverSheets e) A receiver sheet was prepared by separately coating and drying the following aqueous solutions (pH 5.5) on polyethylene coated paper (concentrations are in grams per square meter unless otherwise stated): Layer 1 gelatin 2.2 formaldehyde - 0.03 Layer2 polyvinylimidazole (10 percentquaternized with 2-chloroethanol) 2.2 4-hydroxymethyl-4-methyl-1 -phenyl-3 pyrazolidone Q122 formaldehyde Q03 This receiver e) constitutes a control.

f) Another receiver was prepared similarto e), except that Layer 1 was: gelatin 2.2 formaldehyde 0.03 Compound 1 0.81 N-n-butylacetanilide 1.6 Aerosol OT (trademark) surfactant 0.07 ii) Preparation of Photosensitive Element A photosensitive element was prepared by coating the following layers in the order recited on a poly(ethylene terephthalate) film support.Quantities are parenthetically given in grams per square metre unless otherwise stated: (1) cyan dye-providing layer of gelatin (1.5), cyan RDR D (0.45) dispersed in N,N-diethyl-lauramide (0.22), and bis(vinylsulfonylmethyl)ether (0.03); (2) red-sensitive, direct-positive, 0.75 ym silver bromide emulsion (silver 0.35, gelatin 1.0), 1 dimethyl - 3 - 04 - (2 - formylhyd razino)phenyl thiourea (10 mg/silvermol); (3) interlayer of gelatin (1.0) and 2,5-di-secdodecylhydroquinone (0.5); (4) magenta dye-providing layer of magenta RDR E(0.45) dispersed in N,N-diethyl-lauramide (0.22), gelatin (1.0) and bis(vinylsulphonylmethyl)ether (0.03);; (5) green-sensitive, direct-positive, 0.75 jm silver bromide emulsion (silver 0.35, gelatin 1.0), 1 - methyl - 3[4 -(2 - formylhydrazino)phenyl ] thiourna (25 mg/silver mol); (6) interlayer of gelatin (1.0) and 2, 5 - di - sec dodecylhydroquinone (0.5); (7) yellow dye-providing layer of yellow RDR F (0.5) dispersed in N,N-diethyl-lauramide (0.25), gela tiro(1.0) and bis(vinylsulphonylmethyl)ether (0.03); (8) blue-sensitive, direct-positive, 0.75 #m silver bromide emulsion (silver 0.35, gelatin 1.0), 1 - methyl - 3[4 - (2 - formylhydrazino)phenyl ] thiourea (15 mg/silvermol); and (9) overcoat layer of gelatin (1.0) and copoly [ styrene - (N, N - dimethyi- N - benzyl - N - 3 maleimidopropyl)ammonium chlorides (0.05).

iii) Testing ofReceiver Sheets Portions of the photosensitive element of ii) were exposed to a sensitometric light source. They were soaked in the activator solution described below at 280C for 30 seconds, then withdrawn and squeegeed into intimate face-to-face contact with a portion of the receiver sheets of i).

Activator Solution potassium hydroxide 42 g benzyl alcohol 10 ml 5-methylbenzotriazole 3 9 water to 1 lit The coatings were peeled apart after 3.5 and 6 minutes at 21 C. A positive dye image was visible on the receiving sheets. The image was measured with a reflection densitometer through red, green and blue filters. In Table Ill are listed Dmin and speed values (speed equals-relative Loglo exposure).

TABLEIII Dmin Speed Development Time Receiver Restrainer (minutes) Red Green Blue Red Green Blue (e) None 3.5 0.46 0.27 0.33 1.46 1.80 1.07 6 0.53 0.30 0.37 d 1.43 1.71 1.02 A 0.07 0.03 0.04 -0.03 -0.09 -0.05 (f) Compound 1 3.5 0.46 0.27 0.35 1.47 1.82 1.06 6 0.50 0.30 0.37 1.46 1.86 1.07 A 0.04 0.03 0.02 -0.01 as0.04 +0.01 The results show that the compound of the invention had the desired effect of minimizing sensitometric changes as the processing time was increased from 3.5 to 6 minutes.

In the names of the compounds 1 to 6 the 5(6) position of the methyl group indicates that isomers of the compound were obtained with the methyl group at the 5 or 6 position. Similarly, in the names of the compounds 10 and 11 the 4,6 (5,7) positions of the methyl groups indicates that isomers were obtained with the methyl groups at the 4,6 or 5,7 positions.

Claims (35)

1. A process of photographic reproduction in which an imagewise exposed light-sensitive silver halide layer is developed and the development restrained by a heterocyclic compound having a nit rogen atom in the heterocyclic ring which compound has been formed after the commencement of development by hydrolysis of a precursor for the heterocyclic compound having an alkali hydrolysable N-substituted carbamoyl group on said heterocyclic nitrogen atom, characterised in that said N-substituted carbamoyl group is a di-N,N substituted carbamoyl group.

2. A process according to Claim 1, said heterocyclic ring containing two or more nitrogen atoms.

3. A photographic element comprising a support having thereon at least one photosensitive silver halide emulsion layer with which is associated a dye image-providing material and comprising also a compound which has an azole ring containing at least two nitrogen atoms, and which has an alkalihydrolyzable, N,N-disubstituted carbamoyl group on one of said two nitrogen atoms.

4. A photographic element according to Claim 3 wherein said azole compound has the following formula: wherein:

R' and R2 each represent a substituted or unsubstituted alicyclic, aliphatic, aromatic or heterocyclic moiety or, taken together with the nitrogen to which they are attached, form a heterocyclic ring; and Z represents the atoms necessary to complete an azole ring containing at least two nitrogen atoms.

5. A photographic element according to Claim 3 wherein said azole ring is a triazole, tetrazole, imidazole or benzimidazole.

6. A photographic element according to Claim 3 wherein said azole ring is a benzotriazole.

7. A photographic element according to Claim 6 wherein said compound has either of the following formulas:

wherein: R' and R2 each represent a substituted or unsubstituted alicyclic, aliphatic, aromatic or heterocyclic moiety or, taken together with the nitrogen to which they are attached, form a heterocyclic ring; and R3, R4, R5 and R6 each represent hydrogen, nitro, alkyl, halogen, carbamoyl, sulphamoyl, RCONH- or RSO2NH~, wherein R is alkyl or aryl.

8. A compound according to Claim 7, each of R3, R4 and R8 being H and Rs being CH3.

9. A photographic element according to any of Claims 4 to 8, each of R' and R2 being a substituted or unsubstituted alkyl or aryl group.

10. A photographic element according to Claim 9, each of R' and R2 being ethyl, phenyl, 4-methoxyphenyl or-(CH2)10-COOC2H5.

11. A photographic element according to any of Claims4to 8, R' and R2 together completing a morpholine or piperidine ring.

12. A photographic element according to Claim 7 wherein said compound is:

13. Aphotographic element according to Claim 7 wherein said compound is:

14. A photographic element according to any of Claims 3 to 13 wherein said dye image-providing material is a ballasted, redox-dye-releasing compound.

15. A photographic element according to Claim 14 wherein said dye-releasing compound is a p-sulphonamidonaphthol.

16. A photographic element according to any of Claims 3 to 15 which comprises a support having thereon a red-sensitive silver halide emulsion layer having a cyan dye image-providing material associated therewith, a green-sensitive silver halide emulsion layer having a magenta dye image-providing material associated therewith, and a blue-sensitive silver halide emulsion layer having a yellow dye image-providing material associated therewith.

17. A photographic assemblage comprising a photographic element comprising a support having thereon at least one photosensitive silver halide emulsion layer having associated therewith a dye image-providing material and a dye image-receiving layer; and comprising also an azole compound as defined in any of Claims 1 to 13.

18. A photographic assemblage according to Claim 17 comprising also an alkaline processing composition and means containing same for discharge within said assemblage; which assemblage also contains silver halide developing agent

19. A photographic assemblage according to Claim 18 wherein said discharging means is a rupturable containercontaining said alkaline processing composition and an opacifying agent, said container being so positioned during processing of said assemblage that a compressive force applied to said container will effect a discharge of the container's contents between said transparent sheet and the layer outermost from said support.

20. A photographic assemblage according to Claim 17, t8 or 19 wherein said photographic element is an element defined in Claim 16.

21. A photographic assemblage according to any of Claims 17 to 20 wherein: (a) said dye image-receiving layer is located between said support and said silver halide emulsion layer; and (b) said assemblage also includes a transparent cover sheet over the layer outermost from said support.

22. A photographic assemblage of Claim 21 wherein said cover sheet has thereon a neutralizing layer and a timing layer thereover.

23. A photographic assemblage according to any of Claims 17 to 22 wherein said support having thereon said photosensitive silver halide emulsion layer is opaque and said dye image-receiving layer is located on a separate transparent support and is superposed over the layer outermost from said opaque support.

24. A photographic assemblage of Claim 23, wherein said transparent support has thereon, in sequence, a neutralizing layer, a timing layer and said dye image-receiving layer.

25. A photographic assemblage according to any of Claims 17 to 22 wherein said dye image-receiving layer is located on a separate support to form a receiving element, said receiving element being adapted to be superposed on said photosensitive element after exposure thereof.

26. A photographic assemblage according to Claim 25 wherein said receiving element contains said azole compound.

27. A process for producing a photographic image in colour which comprises imagewise exposing a photographic element comprising a support having thereon at least one photosensitive silver halide emulsion layer with which is associated a dye image-providing material, said process comprising: (a) treating the exposed element with an alkaline processing composition in the presence of a silver halide developing agent to effect development of each exposed silver halide emulsion layer, whereby an imagewise distribution of said dye is formed as a function of said development of said silver halide emulsion layer; and (b) allowing at least a portion of said imagewise distribution of said dye to diffuse out of said element, said process being performed in the presence of an azole compound as defined in any of Claims 1 to 13.

28. A process according to Claim 27 wherein said azole compound is initially present in said dye image-receiving layer or in a layer behind said receiving layer.

29. A process according to Claim 27 or 28 wherein said imagewise distribution of said dye diffuses to a dye image-receiving layer.

30. A dye image-receiving element comprising a support having thereon a dye image-receiving layer, and comprising also an azole compound as defined in any of Claims 1 to 13.

31. A cover sheet comprising a transparent sup port having thereon a neutralizing layer and a timing layerthereover, and also comprising an azole com pound as defined in any of Claims 1 to 13.

32. A dye image-receiving element substantially as described in Example 18c, 18d or 19f herein.

33. A compound as defined in Claim 6,7 or 8.

34. A compound as defined in Claim 9, 10 or 11 as appendantto Claim 7 or 8.

35. A compound of a formula in the series 1 to 21 and 32 to 35 herein.