Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C8/00—Diffusion transfer processes or agents therefor; Photosensitive materials for such processes
  • G03C8/40—Development by heat ; Photo-thermographic processes
  • G03C8/4013—Development by heat ; Photo-thermographic processes using photothermographic silver salt systems, e.g. dry silver
  • G03C8/404—Photosensitive layers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/494—Silver salt compositions other than silver halide emulsions; Photothermographic systems ; Thermographic systems using noble metal compounds
  • G03C1/498—Photothermographic systems, e.g. dry silver

Definitions

• the invention relates to a heat developable processing color photographic recording material having at least one coated layer on a support a binder layer containing photosensitive silver halide and a non-diffusing color-providing compound, wherein said recording material further contains a the D m i n / D max -relation and the sensitivity-improving compound.
• color-providing compound are those which can be embedded in the layer of a photographic recording material in non-diffusing form and which, as a result of the development, can release a diffusible dye (color releaser).
• color releaser a diffusible dye
• the particular suitability of such color releasers is based on the fact that the colorants released imagewise can be transferred to special image-receiving layers Formation of a brilliant color image that is not overlaid with annoying image silver or silver halide and accordingly does not require any after-treatment. Combining the heat development process with the color diffusion process thus results in an advantageous rapid process for producing colored images.
• a suitable recording material for this is described, for example, in DE-A-32 15 485.
• a recording material having a layer containing a combination of silver halide, silver benzotriazolate, a color releasing agent and guanidine trichloroacetate is exposed imagewise and then subjected to heat treatment in contact with an image-receiving sheet, whereby the image-released dye is transferred to the image-receiving sheet .
• the silver halide in each of these combinations being sensitive to a different spectral range of the light and, in accordance with its spectral sensitivity, containing a color releaser which releases a dye of a different color, usually a color that is complementary is the color of the light for which the silver halide in question has a predominant sensitivity.
• Such assignments can be arranged one above the other in different layers.
• Emulsions with a sensitivity such as are customary for colored copying materials are those which have been subjected to chemical ripening in the course of their production, as is the prior art. It has been shown that the emulsions, which are optimized for fog and sensitivity for conventional development processes (wet processing), also have a high sensitivity when developed under conditions known for photothermographic processes, but have a tendency to markedly intensified, non-imagewise development . An optimal result cannot be achieved by stabilizing only with NH and / or SH compounds.
• the application is therefore based on the object of specifying a color photographic recording material which can be developed by heat treatment and which is further improved in terms of the Dmin / Dmax ratio and in terms of sensitivity.
• the present invention relates to a heat-developable photographic recording material having at least one binder layer applied to a layer, which contains light-sensitive silver halide, and optionally further layers and at least one non-diffusing coloring compound, which is a result of the development treatment is capable of releasing a diffusible dye by heat treatment, which is characterized in that at least one binder layer contains a chemically matured silver halide emulsion and a soluble bromide or iodide.
• the soluble bromides and iodides are alkali bromides or iodides, in particular sodium bromide, potassium bromide, sodium iodide and potassium iodide; however, other soluble bromides and iodides are also suitable.
• the soluble halides mentioned can be added directly to the casting solution of the photothermographic layer in question or else added to the recording material via one of the auxiliary layers. The quantities used can be varied within a wide range. The skilled worker can easily determine the appropriate concentration using simple routine tests.
• the halides are preferably added in concentrates of 1-100 mg / m 2 .
• An essential component of the heat-developable recording material according to the invention is therefore the silver halide, which consists of silver chloride, silver bromide, silver iodide or mixtures thereof and can have a particle size between 0.02 and 2.0 ⁇ m, preferably between 0.1 and 1.0 ⁇ m. These can be heterodisperse or largely homodisperse silver halide emulsions.
• the silver halide grains can have a regular crystal structure, for example in the form of cubes or octahedra. But you can also have an irregular crystal structure have or be formed in platelet form, for example, with an aspect ratio of greater than 3: 1. In the case of mixed crystals, the silver halides can be distributed uniformly over the entire crystal cross section.
• the silver halide composition can also be different in different areas.
• silver halide emulsions with a layered grain structure can also be used, in which there are at least two zones with different silver halide compositions.
• a silver bromide iodide emulsion is used whose iodide content on the surface of the silver halide grains is 0-10 mol%.
• Negative working silver halide emulsions are generally used; In other embodiments, however, directly positive-working silver halide emulsions can also be used, as described, for example, in DE-A-23 32 802, DE-A-23 08 239 and DE-A-22 11 728.
• the photosensitive silver halide emulsion used in the invention is chemically ripened; it can also be spectrally sensitized in a known manner by means of suitable additives, it being possible for the spectral sensitizer to be added before, during or after chemical ripening.
• a chemically ripened emulsion is understood to mean a silver halide emulsion which has been subjected to a treatment in the presence of chemical sensitizers.
• the chemical sensitizers are, for example, active gelatin, sulfur or selenium compounds, such as rodanides, thiosulfate or thiourea, noble metal compounds, such as compounds of gold, platinum, palladium, Iridium, or reducing agents such as tin (II) chloride or aminoborane.
• the chemical ripening is expediently carried out at a slightly elevated temperature, for example at 53 ° C., to such an extent that the highest possible and most stable sensitivity is achieved.
• the sensitivity of the chemically ripened silver halide emulsion according to. lying invention is preferably at least 60% (logarithmic scale) of the maximum sensitivity that can be achieved with the same emulsion.
• the amount of light-sensitive silver halide in the respective layer can be between 0.01 and 3.0 g per m 2 , the actual amount of silver halide used depending on the requirements of the reactants used and the desired effects.
• Silver salts of compounds with an imino group are suitable.
• these include silver salts of benzotriazole and its derivatives, e.g. Silver salts of alkyl, hydroxy, sulfo and / or halogen substituted benzotriazoles.
• heterocyclic mercaptoazolecarboxylic acids or sulfonic acids mentioned are known compounds; their manufacture is described in the relevant literature.
• Another essential component of the recording material according to the invention is a non-diffusing coloring compound. As a result of a redox reaction that occurs during development, this can release a diffusible dye. In the following, it is referred to as a paint splitter.
• the dye releasers used according to the invention can be a variety of connection types, all of which are distinguished by a link which is redox-dependent in terms of their bond strength and which links a dye residue to a carrier residue containing a ballast residue.
• Such residues are to be regarded as ballast residues which make it possible to store the color releasers according to the invention in a diffusion-resistant manner in the hydrophilic colloids usually used in photographic materials.
• Organic radicals which generally contain straight-chain or branched aliphatic groups with generally 8 to 20 C atoms and optionally also carbocyclic or heterocyclic optionally aromatic groups are preferably suitable for this purpose.
• These residues are connected to the rest of the molecule either directly or indirectly, for example via one of the following groups: -NHCO-, -NHS0 2 -, -NR-, where R is hydrogen or alkyl, -0- or -S-.
• ballast residue can also contain water-solubilizing groups, such as 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, for example if the total molecule used is large enough, to use shorter-chain residues as ballast residues.
• Redox-active carrier residues of the BALLAST-REDOX structure and corresponding color releasers are known in a wide variety of embodiments. A detailed description can be omitted here with regard to the above-mentioned article in the app. Chem. Int. Ed. Engl. 22 (1983) 191-209.
• the groups enclosed in brackets are functional groups of the dye residue and are separated together with this from the remaining part of the carrier residue.
• the functional group can be a substituent which can have a direct influence on the absorption and, if appropriate, complex formation properties of the released dye.
• the functional group can also be separated from the chromophore of the dye by an intermediate link or a link.
• the functional group together with the intermediate member may also be of importance for the diffusion and pickling behavior of the released dye.
• Suitable intermediate members are, for example, alkylene or aryl groups.
• the residues of dyes of all classes of dyes are suitable as dye residues insofar as they are sufficiently diffusible to diffuse from the light-sensitive layer of the light-sensitive material into an image-receiving layer.
• the dye residues can be provided with one or more alkali-solubilizing groups.
• Suitable alkali-solubilizing groups include carboxyl groups, sulfo groups, sulfonamide groups and aromatic hydroxyl groups.
• Such alkali-solubilizing groups may already have been pre-formed in the dye releasers used according to the invention or may only result from the cleavage of the dye residue from the carrier residue which contains ballast groups.
• dyes which are special for the process according to the invention Suitable are to be mentioned: azo dyes, azomethine dyes, anthraquinone dyes, phthalocyanine dyes, indigo dyes, triphenylmethane dyes, including those dyes that are complexed or complexable with metal ions.
• the residues of dye precursors are to be understood as the residues of those compounds which, in the course of photographic processing, in particular under the conditions of heat development, be it by oxidation, by coupling, by complex formation or by exposure of an auxochromic group in a chromophoric system, for example by saponification, can be converted into dyes.
• Dye precursors in this sense can be leuco dyes, couplers or dyes that are converted into other dyes during processing. Unless a distinction between dye residues and the residues of dye precursors is essential, the latter should also be understood below as dye residues.
• Suitable color releasing agents are described, for example, in:
• the color releasers can be present as oxidisable or couplable color releasers, in others as reducible color releasers.
• the dye is released from the oxidized or from the reduced form of the color releasing agent, negative or positive illumination is obtained from the original when conventional negative-working silver halide emulsions are used. You can therefore create positive or negative images by selecting suitable color releasing systems.
• DE-A-26 45 656 is described, for example, in DE-A-26 45 656 which is particularly suitable for the heat-developable recording materials according to the invention.
• the color splitter can be oxidized, then it is itself a reducing agent which is oxidized directly or indirectly with the aid of electron transfer agents (electron transfer agent, ETA) through the imagewise exposed silver halide. This creates a pictorial differentiation in terms of the ability to release the diffusible dye.
• the color releaser is reducible, then it is expediently used in combination with a reducing agent present in a limited amount, a so-called electron donor compound or an electron donor precursor compound, which in this case in addition to the color releaser and the photosensitive Silver halide is contained in the same binder layer. Even if reducible color releasers are used in combination with electron donor compounds, the participation of electron transfer agents can prove to be favorable.
• the electron donor compound used in combination with a reducible dye releasing agent serves equally as a reducing agent for the silver halide and the color releasing agent. Because the silver halide and the color releaser compete with each other to a certain extent in the oxidation of the electron donor compound, but is superior to the latter, the silver halide present becomes determinant for the image areas within which the color releaser is due to the electron donor compound its reduced form is transferred.
• the electron donor compound which is present in a limited amount, is processed under the conditions of development, e.g. when the imagewise exposed color photographic material is heated, oxidized in accordance with the extent of the exposure and is consequently no longer available for a reaction with the color releaser. This creates an image-like distribution of unused electron donor compound.
• electron donor compounds are known from DE-A-29 47 425, DE-A-30 06 268, DE-A-31 30 842, DE-A-31 44 037, DE-A-32 17 877 and EP-A- 0 124 915 and Research Disclosure 24 305 (July 1984). It has been shown that the electron donor compounds mentioned also meet the requirements placed on them under the conditions of heat development and are therefore also suitable as electron donor compounds in the context of the present invention. Particularly suitable are those electron donor compounds which are formed from the corresponding electron donor precursor compounds only under the conditions of heat development in the layer, i.e. Electron donor compounds that are only in a masked form in the recording material before development, in which they are practically ineffective. Under the conditions of heat development, the electron donor compounds, which are initially ineffective, are then converted into their effective form, for example by hydrolytically cleaving off certain protective groups. In the present case, the electron donor precursor compounds mentioned are also understood as electron donor compounds.
• coupling-releasable dye releasers which can release a diffusible dye as a result of a coupling reaction.
• the dye is only formed by chromogenic coupling, whereby a diffusion-inhibiting ballast group is split off from the coupling position.
• non-diffusing couplers which contain an already formed dye residue as an escape group in the coupling point, which is split off by coupling and thus becomes diffusible.
• the dye releasers can also be polymeric couplers of the dye-releasing type, as described, for example, in DE-A-34 22 455.
• the above-mentioned essential constituents of the recording material according to the invention namely the light-sensitive silver halide and the color releaser, optionally in combination with an electron donor compound, and the soluble halide used according to the invention are present next to one another in dispersed form in a binder.
• a binder can be hydrophobic as well as hydrophilic binders, but the latter are preferred.
• gelatin is preferably used for the light-sensitive layer. However, this can be replaced in whole or in part by other natural or synthetic binders.
• Suitable natural binders include, for example, alginic acid and its derivatives such as salts, esters or amides, cellulose derivatives such as carboxymethyl cellulose, alkyl cellulose such as hydroxyethyl cellulose, starch and its derivatives and caragenates.
• Synthetic binders include polyvinyl alcohol, partially saponified polyvinyl acetate and polyvinyl pyrrolidone.
• hydrophobic binders are polymers made from polymerizable ethylenically unsaturated monomers such as alkyl acrylates, alkyl methacrylates, styrene, vinyl chloride, vinyl acetate, acrylonitrile and acrylamides. Furthermore, polyester, polyurethane compounds and waxes can be used. Such polymers can be used in latex form, for example.
• the light-sensitive binder layer contains one or more color releasers associated with the light-sensitive silver halide, from which dyes of a specific color are released.
• the overall resulting color can be obtained by mixing several dyes.
• this contains color photographic recording material of the present invention a plurality, that is to say three, of assignments of color releasers and in each case differently spectrally sensitized silver halide, preferably in each case the absorption range of the dye released from the color releaser essentially matching the range of the spectral sensitivity of the assigned silver halide.
• the various assignments of color releaser and assigned silver halide can be accommodated in different binder layers of the color photographic recording material, with separating layers of a water-permeable binder, for example gelatin, which preferably contain a scavenger for developer oxidation products, which essentially have the function, between these different binder layers to separate the different assignments from each other and thus counteract color distortion.
• a water-permeable binder for example gelatin
• a scavenger for developer oxidation products which essentially have the function
• the color photographic recording material of the present invention contains, for example, a light-sensitive binder layer in which the silver halide contained therein is predominantly red-sensitive due to spectral sensitization and in which a cyan color releaser is contained, a further light-sensitive binder layer in which the silver halide contained therein by spectral sensitization is predominantly green-sensitive and contains a purple dye-releasing agent, and a third light-sensitive one Binder layer in which the silver halide contained therein is predominantly blue-sensitive due to its intrinsic sensitivity or by spectral sensitization and in which a yellow dye releaser is contained.
• each of the cited combinations of photosensitive silver halide and color releaser is used in the form of a so-called complex coacervate.
• a complex coacervate is understood to mean a form of dispersion in which a mixture of the essential constituents is enclosed in a common covering made of a hardened binder. Such dispersions are also called packet emulsions. They are obtained through complex coacervation.
• packet emulsions enable, according to the invention, the combination of several emulsion components of different spectral sensitivity, including the relevant color releasers, in a single binder layer without the spectral assignment being lost and thereby a color falsification occurring. This is possible because the degree of exposure of a particular silver halide particle becomes almost exclusively the determining factor for the degree of dye release from the color releaser which is in the same coacervate particle (package) as the silver halide.
• the use of packet emulsions thus enables a blue-sensitive, a green-sensitive and a red-sensitive silver halide emulsion and spectrally assigned color separators to be accommodated in the same binder layer, without fear of serious color falsification.
• the color photographic recording material according to the invention may contain further constituents and auxiliaries which are beneficial, for example, for carrying out the heat treatment and the color transfer which takes place here.
• these further constituents or auxiliary substances can be contained in a light-sensitive layer or in a non-sensitive layer.
• auxiliaries are, for example, auxiliary developers.
• auxiliary developers generally have developing properties for exposed silver halide; in the present case, they primarily have a beneficial effect on the reactions taking place between the exposed silver halide and the reducing agent, the reducing agent being able to be identical to the latter when using oxidizable color releasers or, in the case of using reducible color releasing agents, from the color releasing agent responds. Since this reaction mainly consists of electron transfer, the auxiliary developers are also referred to as electron transfer agents (ETA).
• ETA electron transfer agents
• auxiliary developers include hydroquinone, pyrocatechol, pyrogallol, hydroxylamine, ascorbic acid, 1-phenyl-3-pyrazolidone and their derivatives, for example 4-methyl-1-phenyl-3-pyrazolidone, 4,4-dimethyl-1-phenyl- 3-pyrazolidone, 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone, 4-hydroxymethyl-4-methyl-1-tolyl-3-pyrazolidone and 4,4-dihydroxymethyl-1-phenyl-3- pyrazolidone. In certain cases it is advantageous to use them in masked form with a protective group that can be split off under alkaline conditions.
• auxiliary developers have a catalytic function, it is not necessary for them to be present in stoichiometric amounts. In general, it is sufficient if they are used in amounts up to 1/2 mol per mol of color releaser in the layer available. Incorporation into the layer can take place, for example, from solutions in water-soluble solvents or in the form of aqueous dispersions which have been obtained using oil formers.
• Color developers are required for coupling color systems. Reference is made here to the customary phenylenediamine developers and also to aminophenols. For reasons of stability, it is advantageous to use the developer additives in masked form, the protective group then being split off under the process conditions.
• auxiliaries are compounds that activate development.
• Bases or base precursors ie compounds with a pka value of 8 and more, are suitable.
• suitable inorganic bases are hydroxides, secondary and tertiary phosphates, borates, carbonates of alkali or alkaline earth metals, or ammonium hydroxide.
• Suitable organic bases are, for example, aliphatic amines, heterocyclic amines, amidines, cyclic amidines, guanidines or cyclic guanidines.
• Base precursors are compounds that are capable of releasing a base component when heated.
• Salts of the above-mentioned bases with heat-decomposable organic acids such as, for example, trichloroacetic acid, acetoacetic acid, cyanoacetic acid, sulfonylacetic acid or acetylenecar are suitable Bon acids.
• base precursors with covalent binding of the base which release the base in the heat, for example via a fractionation reaction.
• auxiliaries are, for example, compounds which are able to release water under the action of heat.
• crystal water-containing inorganic salts are suitable, for example, Na 2 S0 4 .10H 2 0, NH 4 Fe (SO 4) 2 ⁇ 12H 2 O.
• the water released during heating favors the development and diffusion processes required for image formation.
• thermal solvents are generally understood to mean non-hydrolyzable organic compounds which are solid under normal conditions but melt when heated up to the temperature of the heat treatment and thereby provide a liquid medium in which the development processes can take place more quickly.
• thermal solvents can act as diffusion accelerators, for example.
• Preferred examples of the thermal solvents include polyglycols, as described, for example, in US Pat. No. 3,347,675, for example polyethylene glycol with an average molecular weight of 1500 to 20,000, derivatives of polyethylene oxide, such as, for example, its oleic acid ester, beeswax, monostearin.
• compounds with a high dielectric constant are suitable which have an -SO Z or -CO group.
• auxiliaries are development accelerators. Mention may be made here, for example, of sulfonamides which are described in EP-A-0 160 313 and DE-A-33 39 810.
• pH-lowering agents can be added, which above all help to stabilize the minimum densities.
• Suitable compounds are acid precursor compounds as described, for example, in DE-A-34 42 018 and DE-A-35 15 176.
• the development of the imagewise exposed color photographic recording material according to the invention comprises the partial steps of silver halide development, generation of an imagewise distribution of diffusible dyes and diffusion transfer of this imagewise distribution into the image receiving layer. It is initiated by subjecting the exposed recording material to a heat treatment in which the photosensitive binder layer is brought to an elevated temperature, for example in the range from 80 to 250 ° C., for a period of about 0.5 to 300 s.
• a heat treatment in which the photosensitive binder layer is brought to an elevated temperature, for example in the range from 80 to 250 ° C., for a period of about 0.5 to 300 s.
• suitable conditions for the development processes, including dye diffusion are created in the recording material without the addition of a liquid medium, for example in the form of a dew winding bath needs.
• dyes which are diffusible in terms of image are released from the dye releasers and transferred to an image-receiving layer which is either an integral part of the color photographic recording material according to the invention or is in contact with it at least during the development period.
• Image-wise silver development, dye release and color transfer take place synchronously in a one-step development process.
• the color image formation with the color photographic recording material according to the invention can also take place in a two-step development process, silver halide development and dye release taking place in a first step, followed in a second step by color image transfer from the light-sensitive part to an image receiving part brought into contact with it, e.g. by heating to a temperature between 50 and 150 ° C., preferably to 70 to 90 ° C., in which case diffusion aids (solvents) can still be applied externally before the photosensitive part and the image receiving part are laminated.
• diffusion aids solvents
• the image-receiving layer can accordingly be arranged on the same layer support as the light-sensitive element (single sheet material) or on a separate layer support (two-sheet material). It consists essentially of a binder, the mordant for contains the determination of the diffusible dyes released from the non-diffusing paint releasing agents. Long-chain quaternary ammonium or phosphonium compounds are preferably used as mordants for anionic dyes, for example those as described in US Pat. Nos. 3,271,147 and 3,271,148.
• stains are also polyvinylimidazole stains which are partially quaternized, for example with benzyl, hydroxyethyl, alkyl, epoxypropyl, propyl, methyl and ethyl halides, the degree of quaternization being between 5 and 50%.
• the dye mordants are dispersed in the mordant layer in one of the usual hydrophilic binders, for example in gelatin, polyvinyl alcohol, polyvinyl pyrrolidone, completely or partially hydrolyzed cellulose esters.
• some binders can also act as mordants, for example polymers of nitrogen-containing, optionally quaternary bases, such as N-methyl-4-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, as described, for example, in US Pat. No. 2,484,430.
• Others Useful pickling binders are, for example, guanylhydrazone derivatives of alkyl vinyl ketone polymers, as described, for example, in US Pat. No.
• the image-receiving layer remains in layer contact with the light-sensitive element even after development is complete, there is usually an alkali-permeable, pigment-containing, light-reflecting binder layer between them, which serves for the optical separation between negative and positive and as an aesthetically pleasing background for the transferred positive color image.
• the image-receiving layer is arranged between the support and the photosensitive element and is separated from the latter by a pre-formed light-reflecting layer, either the support must be transparent so that the color transfer image produced can be viewed through it, or the photosensitive element together with the light-reflecting layer of the image-receiving layer are removed to expose the latter.
• the image-receiving layer can also be present as the uppermost layer in an integral color photographic recording material, in which case the exposure is expediently carried out through the transparent layer support.
• stripping layers can also be included, which enable the two layer elements to be separated.
• the supports for the light-sensitive element and, if appropriate, for the image-receiving element must remain dimensionally stable at the process temperature.
• Standard film or paper documents are eligible. Polyester materials are preferably used.
• the conventional hardening agents as well as rapid and instant hardeners, which are customary for photographic materials, can be used as hardening agents for both the light-sensitive element and for the image receiving element.
• Emulsion E 1 platelet-shaped crystals
• composition of the solutions used is given in Table 1.
• Solution A2 is added to the vigorously stirred solution A1 at 50 ° C. over the course of 1 min.
• the mixture is washed 3 times with 2 l of water using the coagulation method and redispersed in 250 ml of water. 330 g of seed precipitation emulsion with platelet-shaped crystals are obtained, the average grain size of which is 0.3 ⁇ m (diameter of a spherical volume).
• the germ precipitation emulsion is heated to 55 ° C. and, after adding 1.13 g of potassium bromide, solutions A5 and A6 are simultaneously added in 50 minutes, with vigorous stirring, the rate of addition being 9 times as high at the end as at the beginning. A pBr of 1.54 is maintained during the addition. After cooling, 12 g of inert bone gelatin are added, washed 3 times with 1 liter of water using the coagulation method and redispersed in 1 liter of water. This gives 1600 g of an emulsion containing silver halide corresponding to 170 g of AgN0 3 per kg of emulsion.
• the emulsion grains are platelet-shaped crystals with an aspect ratio of about 7: 1 and a grain size of 0.6 ⁇ m on average (diameter of a volume of the same volume), they consist of silver iodide bromide with 5 mol% iodide.
• Emulsion E2 (zone crystals)
• a double chloride process was used to prepare a 7-bean silver chloride bromide iodide emulsion containing 4.0 mol% chloride, 88.7 mol% bromide and 7.3 mol-X iodide.
• the crystals were cube-shaped, the average diameter of the same-volume ball was 0.30 ⁇ m.
• the pAg was then increased again to 8.0 by simply running in 2 molar KBr solution at a rate of 10 ml / min and then after the double enema process at pAg 8.0 1800 ml 2-molar AgN0 3 solution and the 2-molar KBr 0.8 I 0.2 solution required to keep the PAG constant are added.
• the pAg was reduced again to 6.3 by simply running in a 2 molar AgNO 3 solution at a rate of 10 ml / min.
• the emulsion was then flocculated, washed and redispersed with 620 g of gelatin and so much water that the total weight of the emulsion was 6.67 kg.
• the pAg was adjusted to 9.0 with 25X NaCl solution.
• the emulsion contained 254.8 g AgN0 3 per kg silver halide, the weight ratio gelatin to silver halide (calculated as AgN0 3 ) was 0.5.
• the emulsion was chemically ripened per mole Ag at 53 ° C. with 39 ⁇ mol Na 2 S 2 O 3 .5H 2 O, 14.7 ⁇ mol HAuCl 4 and 870 ⁇ mol KSCN.
• the structure of the crystals described in Table 2 results from the production.
• a photosensitive member of a photothermographic recording material for the diffusion transfer process was prepared by coating the layers described below on a transparent substrate made of polyethylene terephthalate. The quantities given relate in each case to 1 m 2 .
• the hardening agent is also applied with this protective layer.
• the photosensitive member thus produced is referred to as Sample 1 and serves as a comparative sample.
• samples 2-4 were prepared in an analogous manner using the emulsion prepared according to example 1, the emulsion being 10 minutes (sample 2), 30 minutes (sample 3) and 50 minutes (sample 4) after addition of 10 ⁇ mol Na 2 S 2 0 3 , 3.5 ⁇ mol HAuCl 4 and 500 ⁇ mol rhodanide had been chemically ripened at 55 ° C.
• Samples 5-8 were prepared in a corresponding manner, with the difference that 0.02 g of potassium bromide was added to layer 1.
• An image receiving part for the photothermographic recording material was produced in that the following layers were applied successively to a support made of paper coated with polyethylene.
• the quantities given relate in each case to 1 m 2 .
• a sample of the light-sensitive element (samples 1 - 8) was exposed through a step wedge.
• the development took place in two steps; in the first, the photosensitive element was heated at 120 ° C for 60 s. This was done with the help of a heating plate, the sample being placed on the layer on the heating plate and covered with another plate.
• the sample was brought into contact with the image-receiving element on the layer side, the image-receiving element having previously been soaked with water.
• the set formed in this way was treated for 2 minutes at 70 ° C. using the same procedure as in the first step. During this time the color transfer from the photosensitive element to the image receiving element took place.
• the two layer elements were then separated from one another. A purple negative image of the exposure original was obtained on the image receiving element.
• emulsion E 2 (with zone crystals) was used.
• sample 9 The light-sensitive element thus produced is referred to as sample 9 and serves as a comparison sample.
• Samples 10-13 additionally contain 0.01, 0.02, 0.05 and 0.10 g KBr in layer 1.

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• 1986
  • 1986-05-30 DE DE19863618143 patent/DE3618143A1/de not_active Withdrawn
• 1987
  • 1987-05-18 EP EP87107148A patent/EP0247473A3/fr not_active Withdrawn
  • 1987-05-30 JP JP13355187A patent/JPS62291644A/ja active Pending

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