EP0650084B1 - Emulsion d'halogénure d'argent photographique comprenant des grains à faces (100) avec des cavités - Google Patents

Emulsion d'halogénure d'argent photographique comprenant des grains à faces (100) avec des cavités Download PDF

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Publication number
EP0650084B1
EP0650084B1 EP94420275A EP94420275A EP0650084B1 EP 0650084 B1 EP0650084 B1 EP 0650084B1 EP 94420275 A EP94420275 A EP 94420275A EP 94420275 A EP94420275 A EP 94420275A EP 0650084 B1 EP0650084 B1 EP 0650084B1
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Prior art keywords
silver
grains
core
shell
faces
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German (de)
English (en)
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EP0650084A1 (fr
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Didier Jean Kodak-Pathe Martin
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Kodak Pathe SA
Eastman Kodak Co
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Kodak Pathe SA
Eastman Kodak Co
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    • 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
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/015—Apparatus or processes for the preparation of emulsions
    • 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
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
    • 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
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C1/10—Organic substances
    • G03C1/12—Methine and polymethine dyes
    • G03C1/14—Methine and polymethine dyes with an odd number of CH groups
    • G03C1/18—Methine and polymethine dyes with an odd number of CH groups with three CH groups
    • 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
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/015—Apparatus or processes for the preparation of emulsions
    • G03C2001/0156—Apparatus or processes for the preparation of emulsions pAg value; pBr value; pCl value; pI value
    • 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
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
    • G03C2001/03535—Core-shell grains
    • 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
    • G03C2200/00—Details
    • G03C2200/44—Details pH value

Definitions

  • the present invention concerns silver halide photographic emulsions and particularly silver halide grains of the core/shell type, and a process for obtaining these grains and the corresponding photographic emulsions.
  • the process for forming the photographic image in silver halides comprises a stage of forming a latent image. At the time of exposure, electrons are produced and these electrons migrate in the grain and are trapped at specific sites where the latent image is formed.
  • dispersion of the sites promotes a faster subsequent development but enables only low sensitivity levels to be achieved.
  • the purpose of the sensitisation is to concentrate these sites in order to increase sensitivity. However, in doing this, the development speed is reduced.
  • European patent 523,464 discloses a silver halide photographic emulsion comprising silver halide grains having a cubic crystal lattice structure, and comprising at least ⁇ 1,1,1 ⁇ and/or at least ⁇ 1,0,0 ⁇ crystal face having at least one cracked or hollow zone, around which silver halide protrusions from at least one crater and/or at least one hopper structure on at least one crystal face of said silver halide grains
  • the present invention relates to silver halide grains with a sensitivity which is improved because of the better concentration of the latent image sites, resulting from the particular morphology of these grains, and a process for obtaining these grains.
  • the process according to the invention comprises the following stages:
  • the pAg is adjusted to between 7.5 and 8.0 by means of a silver nitrate solution and to between 7.5 and 6.0 by means of a simultaneous addition of chlorobromide and nitrate.
  • the photographic silver halide grains according to the invention are cubic or cubo-octahedral grains consisting of a core comprising silver bromoiodide or bromide and a silver chlorobromide shell; these grains have faces (100), 10 to 90% of the surface of which is occupied by a cavity.
  • the present invention is based on the concept that the morphology of the faces (100) of the grains can be modified to the point of forming holes or cavities on these faces by the controlled growth of silver halide on the edges delimiting these faces or on the faces (111). It will obviously be understood that this is only a hypothesis, that the cavities thus formed on the faces (100) constitute favoured centres for the subsequent deposition or adsorption of substances, for example sensitising dyes, which can then help to orientate the chemical sensitisation on favoured sites.
  • the emulsions according to the invention are cubic or cubo-octahedral emulsions obtained by precipitating, in a first stage, a first silver halide which constitutes the core of the grains, and then, in a second stage, a second silver halide which constitutes the shell of the grains. It is by modifying the conditions of precipitation of the shell that, under conditions described below, the cavities are obtained on the faces (100) of the grains. Consequently, the formation of these cavities on the faces (100) is also dependent on an appreciable variation in the crystalline phase between the core of the grain and its peripheral part, or shell.
  • the core consists of silver bromide or silver bromoiodide.
  • the quantity of iodide may represent up to 30% molar and advantageously between 5 and 20% molar with respect to the total quantity of silver in the grains.
  • the presence of iodide in the core of the grain, without being a necessary condition, assists the formation of the cavities in the faces (100) of the shell.
  • the shell contains silver chlorobromide.
  • the chloride content is between 3 and 20% molar and advantageously between 5 and 15% molar with respect to the total quantity of silver in the grain.
  • the optimum chloride content of the shell is between 10 and 15% molar, and when the core comprises silver bromoiodide, the optimum chloride content of the shell is between 3 and 25% molar with respect to the total quantity of silver.
  • the present invention has the dual characteristic that the growth of the halide in the shell is modified and a modification of the crystalline phase between the core and the shell is created. This is achieved by modifying the parameters of the precipitation of the shell of the grains, namely the growth profile of the shell, the pAg, the agitation and the temperature.
  • the process for preparing the silver halide grains according to the invention comprises the following stages:
  • silver bromoiodide is precipitated in the growth stage (b).
  • the core of the grains then consists of silver bromoiodide.
  • the total quantity of iodide represents, in the core of the grains, up to 30% molar with respect to the total quantity of silver in the grain.
  • the pAg is adjusted to a value between 7.5 and 8.0 by means of silver nitrate and to a value between 6.0 and 7.5 with a simultaneous addition of silver nitrate and chlorobromide.
  • stage (d) the flow rates of silver nitrate and sodium bromochloride are first accelerated, for example varying from 10 ml to 200 ml and advantageously from 20 ml to 100 ml. Then the flow rates of silver nitrate and sodium bromochloride are thereafter maintained constant, at a value between 50 and 200 ml and advantageously between 70 and 140 ml/min.
  • a process for increasing the size of the silver halide crystals formed by the process described here is to carry out the precipitation in the presence of a silver halide solvent. It is preferred that grain growth or ripening occur inside the reactor during grain formation.
  • Known ripening agents can be used. These comprise ammonia or an excess of halide ions. Consequently, it appears that the halide salt solution run into the reactor can itself promote ripening.
  • solvents or ripening agents which can be entirely contained within the dispersion medium in the reactor, before silver and halide salt addition or they can be introduced into the reactor with one or more halide or silver salts or peptizers.
  • the solvent or ripening agent may be introduced independently during the addition of the halide salts and silver salts.
  • the conventional silver halide solvents suitable for being used in the process of the present invention comprise ammonia, thiocyanates, thiosulphates and various thioethers and thioureas.
  • the solvents based on thioethers comprise the solvents described in US patents 3 271 157, 3 531 289, 3 574 628, 3 767 413, 4 311 638 and 4 725 560.
  • the useful solvents based on thiourea comprise the solvents described in US patents 4 284 717, 4 568 635, 4 695 534, 4 635 535, 4 713 322 and 4 749 646.
  • the silver halide grains produced according to the process of this invention have a bulk iodide content of between 2 and 15%.
  • the size of the grains, as determined by the equivalent circular diameter of their projected surface area, is between 0.1 and 5.0 ⁇ m.
  • the various modifier compounds such as the solvents for silver halides, the ripening agents, the spectral or sensitising dyes or the doping agents etc, may be present during the precipitation of the grains. Depending on the nature of some of these compounds, they may be absorbed within the cavities in the surfaces (100) of the grains.
  • the photographically useful agents such as developers, development accelerators, development inhibitors, dye image forming couplers, etc, or the precursors of such photographically useful agents, may be present during the precipitation of the grains so as to be incorporated within the cavities in the grain. Such agents are then easily available at the various grain development stages, in accordance with the environment in which they are situated.
  • the modifier compounds and the photographically useful agents may initially be in the reactor or they may be added either separately or with one or more of the salts, in accordance with conventional operating methods.
  • the chemical sensitisers and doping agents such as compounds of copper, thallium, lead, bismuth, cadmium, zinc, the middle chalcogens (namely sulphur, selenium and tellurium), the group VIII noble metals and gold, may be present during the precipitation of the silver halides.
  • Research Disclosure and its predecessor, Product Licensing Index are publications of Kenneth Mason Publications Limited, Emsworth, Hampshire, PO10 7DD, United Kingdom.
  • the emulsions can be sensitised internally by reduction during precipitation, as described by Moisar et al, Journal of Photographic Science, Vol 25, 1977, pages 19-27.
  • halide salts and silver salts individually may be added to the reactor by using surface or sub-surface delivery tubes, by gravity feed or by delivery apparatus for maintaining control of the rat of delivery, the pH, the pBr and/or the pAg of the reaction medium.
  • special mixing devices can be used.
  • a dispersion medium is initially introduced into the reactor.
  • the dispersion medium consists of an aqueous peptizer suspension.
  • Peptizer concentrations are between approximately 0.2 and 10% by weight, based on the total weight of emulsion components in the reactor. It is usual practice to maintain the concentration of peptizer in the reactor at a value below approximately 6%, based on the total weight, before and during the formation of the silver halide, and to increase the emulsion vehicle concentration in order to obtain optimum coating characteristics by the delayed supplemetal addition of vehicle.
  • the emulsion as initially formed, contains 5 to 50 g of peptizer per mole of silver halide and preferably approximately 10 to 30 g of peptizer per mole of silver halide.
  • An additional quantity of vehicle can be added subsequently in order to obtain a concentration of up to 1000 g per mole of silver halide.
  • the concentration of vehicle in the final emulsion is preferably greater than 50 g per mole of silver halide.
  • the vehicle preferably represents 30 to 70% by weight of the emulsion layer.
  • the vehicles (which comprise both binders and peptizers) can be chosen from amongst the vehicles generally used in silver halide emulsions.
  • the preferred deflocculants are hydrophilic colloids, which can be used alone or in combination with hydrophobic substances.
  • Suitable hydrophilic substances comprise gelatin, for example alkali-treated gelatin (hide gelatin or cattle bone gelatin) or acid-treated gelatin (pigskin gelatin), gelatin derivatives, for example acetylated gelatin, phthalylated gelatin, etc.
  • the vehicles comprising particularly the hydrophilic colloids, as well as the hydrophobic substances used in combination with the latter, may be employed not only in the layers of emulsion on the photographic elements of this invention, but also in other layers, such as the top layers, the intermediate layers and the layers located below the emulsion layers.
  • the emulsions are preferably washed in order to eliminate the soluble salts.
  • the soluble salts may be eliminated by decantation, filtration and/or chill setting and leaching, as described in US patents 2 316 845 and 3 396 027, by coagulation washing, as described in US patents 2 618 556, 2 614 928, 2 565 418, 3 241 969 and 2 489 341, by centrifugation and decantation of a coagulated emulsion, as described in US patents 2 463 794, 3 707 378, 2 996 287 and 3 498 454, by using hydrocyclones alone or in combination with centrifuges, as described in UK patents 1 336 692 and 1 356 573 and by Ushomirskii et al, Soviet Chemical Industry, Vol 6, No 3, 1974, pages 181-185.
  • the emulsions can be dried and stored, with or without sensitisers, before using them, as described by Research Disclosure, Vol 101, September 1972, Article 10152. It is particularly advantageous to wash the emulsions after the completion of the precipitation
  • the silver halide grains of the present invention may be sensitised chemically by means of active gelatin, as described by T H James, The Theory of the Photographic Process, 4th Ed., Macmillan, 1977, pp. 67-76, or by means of sulphur, selenium, tellurium, gold, platinum, palladium, iridium, osmium, rhodium, rhenium, or phosphorous sensitisers or combinations or these sensitisers, at pAg levels between 5 and 10, pH values between 5 and 8 and temperatures between 30° and 80°C, as described in Research Disclosure, Vol 120, April 1974, Article 12008, Research Disclosure, Vol 134, June 1975, Article 13452, in the US patents 1 623 499 of Sheppard et al, 1 673 522 of Matthies et al, 2 399 083 of Waller et al, 2 642 361 of Damschroder et al, 3 297 447 of McVeigh and 3 297
  • the emulsions can be sensitised chemically in the presence of modifiers finish (chemical sensitisation) - that is to say compounds known to eliminate fogging and increase speed when they are present during the chemical sensitisation, such as azaindenes, azapyradazines, azapyrimidines, benzothiazolium salts and sensitisers comprising one or more heterocyclic rings.
  • modifiers finish chemical sensitisation
  • compounds known to eliminate fogging and increase speed when they are present during the chemical sensitisation such as azaindenes, azapyradazines, azapyrimidines, benzothiazolium salts and sensitisers comprising one or more heterocyclic rings.
  • agents modifying the finish are described in the US patents 2 131 038 of Brooker et al, 3 411 914 of Dostes, 3 554 757 of Kuwahara et al, 3 565 631 of Oguchi et al and 3 901 714 of Oftadahl, in the Canadian patent 778 723 of Walworth and in Duffin, Photographic Emulsion Chemistry, Focal Press (1966), New York, pp 138-143.
  • the emulsions can be sensitised by reduction - for example by means of hydrogen, as described in the US patents 3 891 446 of Janusonis and 3 984 249 of Babcock et al, by processing using a low pAg (for example less than 5) and/or a high pH (for example above 8) or by using reducing agents such as tin chloride, thiourea dioxide, polyamines and borane amines, as described in the US patent 2 983 601 of Allen et al, in the article by Oftadahl et al, Research Disclosure, Vol 136, August 1975, Article 13654, in the US patents 2 518 698 and 2 739 060 of Lowe et al, 2 743 182 and 2 743 183 of Roberts et al, 3 026 203 of Chambers et al and 3 361 564 of Bigelow et al.
  • reducing agents such as tin chloride, thiourea dioxide,
  • the silver halide emulsions used in this invention can be sensitised by conventional techniques described in Research Disclosure, Vol 178, December 1978.
  • the silver halide emulsions record blue radiation, and need not to be spectrally sensitized in the blue part of the spectrum.
  • the silver bromide and silver bromoiodide emulsions can be used for cording blue radiation without incorporating blue sensitisers, although their absorption efficiency is much higher when blue sensitisers are used.
  • the silver halide emulsions, regardless of composition, intented to record radiation in the minus blue, are sensitised spectrally to green or red radiation by using spectral sensitising dyes.
  • the silver halide grains of this invention can be sensitised spectrally by using dyes of various classes, including the class of polymethine dyes, which comprise cyanines, merocyanines, complex cyanines and merocyanines (that is to say tri-, tetra- and polynuclear cyanines and merocyanines), oxonols, hemioxonols, styryls, merostyryls and streptocyanines.
  • polymethine dyes which comprise cyanines, merocyanines, complex cyanines and merocyanines (that is to say tri-, tetra- and polynuclear cyanines and merocyanines), oxonols, hemioxonols, styryls, merostyryls and streptocyanines.
  • One or more spectral sensitising dyes can be used.
  • the dyes with the maximum sensitisation at wavelengths in the visible spectrum and having a wide variety of spectral sensitivity curve shapes are known.
  • the choice and the relative proportions of the dyes depend on the region of the spectrum which it is desired to sensitise and on the shape of the spectral sensititivity curve desired.
  • the dyes with overlapping spectral sensitivity curves often yield, in combination, a curve in which the sensitivity at each wavelength in the overlap area is approximately equal to the sum of the sensitivities of the individual dyes.
  • Combinations of spectral sensitising dyes can be used which result in supersensitisation, that is to say a spectral sensitisation greater in a certain spectral region than the one obtained by using any concentration of one of the dyes alone, or which would result from the additive effect of the dyes.
  • Supersensitisation can be obtained by using selected combinations of spectral sensitising dyes and other additives, such as stabilisers and anti-fogging agents, accelerators or development inhibitors, coating additives, optical brighteners and antistatic agents.
  • Gilman "Review of the Mechanisms of Supersensitisation", Photographic Science and Engineering, Vol 18, 1974, pages 418-430, describes the different mechanisms as well as the compounds which can be responsible for supersensitisation.
  • the spectral sensitisation can be implemented at any stage in the preparation of the emulsion which is known up till now for being useful.
  • the most usual spectral sensitisation is implemented in the art after ending the chemical sensitisation.
  • the spectral sensitisation can be implemented either simultaneously with the chemical sensitisation or before the chemical sensitisation; it can even begin before the end of the precipitation of the silver halide grains, as described in US patent 3 628 960 and in the US patent 4 225 666 of Locker et al.
  • the sensitisation can be enhanced by adjusting the pAg, including varying the pAg in one or more cycles, during the chemical and/or spectral sensitisation. Research Disclosure, Vol 181, May 1979, Article 18155 gives a specific example of adjustment of the pAg.
  • the additives, such as spectral sensitising dyes, in the grains of this invention may be added on all the faces or all the sides of the grains, which makes it possible to obtain a potential increase in the effects derived from these additives.
  • the sensitisation stage may be implemented before the end of the formation of the grains according to the invention. This procedure allows both internal and external surfaces of the grain to be sensitized thereby providing, which enables a high surface/volume ratio and enhanced light absorption .
  • the photographic elements can use conventional additives, as described in Research Disclosure, Article 17643, cited previously.
  • Optical brighteners can be introduced, as described in paragraph V.
  • Anti-fogging agents and sensitisers can be incorporated, as described in paragraph VI.
  • Absorbent and scattering substances can be used in the emulsions made of silver halide grains of the invention and in the separate layers of the photographic elements, as described in paragraph VIII.
  • Hardening agents can be incorporated, as described in paragraph X.
  • Coating additives, as described in paragraph XI, and plasticisers and lubricants, as described in paragraph XII may be present.
  • Antistatic layers as described in paragraph XIII, may be present. The methods of adding the additives are described in paragraph XIV.
  • Matting agents can be incorporated, as described in paragraph XVI. Developers and development modifying agents can be incorporated, if desired, as described in paragraphs XX and XXI.
  • the silver halide emulsion layers and the intermediate layers, top layers and substrate layers, if any, present in the photographic elements can be coated and dried as described in paragraph XV.
  • the layers on the photographic elements can be coated on various supports.
  • Conventional photographic supports include polymer films, paper, metal sheets, glass and ceramic supporting elements, provided with one or more subbing layers to reinforce the adhesion properties, the antistatic, dimensional and abrasion properties, the hardness, friction and antihalation characteristics and/or the other properties of the surface of the support.
  • subbing layers to reinforce the adhesion properties, the antistatic, dimensional and abrasion properties, the hardness, friction and antihalation characteristics and/or the other properties of the surface of the support.
  • the photographic elements can be used to form dye images in these elements though the selective destruction for formation of dyes.
  • the photographic elements can be used to form dye images by using developers containing dye image forming compounds, such as chromogenic couplers.
  • the developer contains a color developping agent (for example a primary aromatic amine) which, in its oxidised form, is capable of reacting with the coupler (coupling) to form the image dye.
  • the dye-forming couplers can be incorporated in the photographic elements, as described in Research Disclosure, Vol 159, July 1977, Article 15930.
  • the dye-forming couplers and the other photographically useful compounds can be incorporated in the hollow part of the grains of this invention. This can be achieved by adding the compounds to the precipitation vessel before completing the formation of the shell of the grains with the cavities and by eliminating therefrom, by washing, the photographically useful compounds which have not been incorporated, etc. These compounds can be released starting from the central part of the grains in the course of the photographic processing.
  • the dye-forming couplers are generally chosen to form subtractive primary image dyes (that is to say yellow, magenta and cyan) and they are non-diffusible colourless couplers, such as 2 and 4 equivalent couplers of the open chain ketomethylene, pyrazolone, pyrazolotriazole, pyrazolobenzimidazole, phenol and naphthol type hydrophobically ballasted for incorporation in the high boiling organic (coupler) solvents.
  • the dye-forming couplers after coupling, are able to release photographically useful fragments, such as development inhibiters or accelerators, bleaching accelerators, reducing agents, solvents for silver halides, pigments, tanning agents, fogging agents, anti-fogging agents, competing couplers, etc.
  • photographically useful fragments such as development inhibiters or accelerators, bleaching accelerators, reducing agents, solvents for silver halides, pigments, tanning agents, fogging agents, anti-fogging agents, competing couplers, etc.
  • phase (I) 3.57 moles of silver was precipitated, and in phase (II) 3.0 moles of silver.
  • stage (d) At the end of stage (d), a chlorobromide shell has been obtained, the faces (100) of which have holes in them.
  • the emulsion was washed in a conventional manner by flocculation.
  • the final emulsion consists of cubo-octahedral grains with an ESD (equivalent spherical diameter) of 1.06 ⁇ m, a COV (volume coefficient of variation) of 7.2% and a total iodide content of 3 moles %.
  • Stage (d) was carried out by using the following flow rates (double jet): Duration Solution Initial flow rate (ml/min) Final flow rate (ml/min) (I) 11.5 min AgNO 3 2.0 M 20 ml/min 49.8 ml/min NaBr 1.7 M 23.5 ml/min 58.8 ml/min NaCl 0.3 M 23.5 ml/min 58.6 ml/min (II) 57.7 min AgNO 3 2.0 M 50 ml/min 50 ml/min NaBr 1.7 M 58.6 ml/min 58.6 ml/min NaCl 0.3 M 58.6 ml/min 58.6 ml/min
  • the emulsion was washed as in Example 1.
  • the final emulsion consists of cubo-octahedral grains with an ESD of 1.04 ⁇ m, a COV of 7.3% and a total iodide content of 3 moles %.
  • the electron microscopy photographs show that less than 5% of these grains have holes on their faces (100).
  • Example 2 The emulsion prepared in accordance with the operating method of Example 1 was sensitised chemically and spectrally in the following manner. After precipitation of the shell and washing, the following were added successively:
  • the emulsion was applied to a cellulose triacetate support at 8.07 mg of silver, 32.3 mg of gelatin and 10.5 mg of the dye-forming coupler whose formula is given below, per dm 2 .
  • the gelatin was hardened with 1.75% bis(vinylsulphonylmethyl)ether.
  • a top layer of gelatin (2.15 mg/dm 2 ) was coated on this layer.
  • the product thus obtained was exposed for 1/100th of a second to a 3000°K light source through a Wratten 9 filter and processed using the Kodak C-41 process for developing colour negative films.
  • Example 2 The operating method of Example 2 was repeated, except that the emulsion prepared in Example 1A, the grains of which have practically no holes, was used. The product is then sensitised, coated, exposed and developed as indicated in Example 2.
  • Example Dmax Dmin Contrast Relative sensitivity ⁇ p 2 (invention) 2.04 0.13 1.33 112 O 3 (comparison) 2.9 0.10 1.41 100 +7 relative sensitivity: calculated at density 0.3 ⁇ p: loss of sensitivity under the effect of a pressure of 25 psi (175 kPa), exerted before exposure.
  • the emulsion prepared in accordance with the operating method of Example 1 is sensitised chemically and spectrally in the following manner. After precipitation of the shell and washing, the following are added successively:
  • the emulsion was coated on a support so as to form a product under the same conditions as in Example 2.
  • the product obtained was processed using the Kodak C-41 process for developing colour negative films.
  • Example 4 The operating method of Example 4 was repeated, but using the emulsion prepared in Example 1A, in which the grains have practically no holes. The product is then sensitised, coated, exposed and processed as in Example 4.

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  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
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Claims (11)

  1. Procédé pour la préparation de grains d'halogénures d'argent à coeur et à coque, sensibles aux rayonnements, caractérisé en ce qu'il comprend les étapes suivantes :
    (a) former dans un milieu de dispersion colloïdale des grains de bromure ou de bromoiodure d'argent avec une teneur totale en iodure de 2 à 15 % en mole par rapport à l'argent, par nucléation à partir de nucléi de bromure ou de bromoiodure d'argent, à un pAg compris entre 8,5 et 9,5, une température comprise entre 40 et 70°C, et un pH compris entre 5,0 et 7,0 ;
    (b) au cours d'une étape de croissance, maintenir les conditions de l'étape (a), jusqu'à obtenir des grains coeur d'un diamètre moyen compris entre 0,1 et 2,0 µm ;
    (c) modifier l'environnement de croissance des grains coeur, en ajustant successivement le pAg à une valeur comprise entre 7,5 et 8,0, puis à une valeur comprise entre 7,5 et 6,0, en maintenant la température à 60°C environ ;
    (d) réaliser la croissance d'une coque de chlorobromure d'argent sur les grains coeur en précipitant le chlorobromure d'argent en deux étapes successives, la première à débit accéléré, la seconde à débit constant, en maintenant le pAg à une valeur comprise entre 7,0 et 7,5, à une température comprise entre 50 et 80°C et un pH compris entre 5,0 et 7,0 de façon à réaliser une croissance préférentielle de chlorobromure d'argent sur les arêtes adjacentes aux faces (100) des grains d'halogénure d'argent et à poursuivre cette croissance jusqu'au point où une cavité a été formée dans la région centrale desdites faces (100).
  2. Procédé selon la revendication 1, caractérisé en ce que dans l'étape (b) on précipite du bromoiodure d' argent.
  3. Grains d'halogénures d'argent cubiques ou cubooctaédriques constitués d'un coeur comprenant du bromure ou du bromoiodure d'argent avec une teneur totale en iodure entre 2 et 15 % en mole par rapport à l'argent, et d'une coque de chlorobromure d'argent, ces grains présentant des faces (100) dont 10 à 90 % de la surface est occupée par une cavité dans une partie centrale de cette face (100).
  4. Grains selon la revendication 3, caractérisés en ce qu'us présente des faces (100) dont 10 à 40 % de la surface est occupée par une cavité.
  5. Grains selon l'une des revendications 3 ou 4, caractérisés en ce qu'ils présentent un diamètre circulaire équivalent compris entre 0,1 et 5,0 µm.
  6. Grains selon l'une des revendications 3 à 5, caractérisés en ce que la coque contient de 10 à 15 % en moles de chlorure par rapport à la quantité totale d'argent du grain.
  7. Grains selon la revendication 6, caractérisés en ce que la coque contient de 15 à 70 % en moles de chlorure par rapport à la quantité totale d'argent du grain.
  8. Grains selon l'une des revendications 3 à 5, caractérisés en ce qu'ils contiennent de jusqu'à 30 % en moles d'iodure dans le coeur par rapport à la quantité totale d'argent du grain.
  9. Grains selon la revendication 8, caractérisés en ce que le coeur contient entre 5 et 15 % en moles d'iodure, et la coque au moins 3 % en moles de chlorure, par rapport à la quantité totale d'argent du grain.
  10. Grains selon l'une des revendications 3 à 9, caractérisés en ce que le rapport molaire coque:coeur est compris entre 1:1 et 5:1 environ.
  11. Produit photographique comprenant au moins une couche d'émulsion qui contient des grains d'halogénures d'argent selon l'une des revendications 3 à 10.
EP94420275A 1993-10-20 1994-10-17 Emulsion d'halogénure d'argent photographique comprenant des grains à faces (100) avec des cavités Expired - Lifetime EP0650084B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9312713A FR2711431B1 (fr) 1993-10-20 1993-10-20 Emulsion d'halogénure d'argent photographique comprenant des grains à faces (100) avec des cavités.
FR9312713 1993-10-20

Publications (2)

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EP0650084A1 EP0650084A1 (fr) 1995-04-26
EP0650084B1 true EP0650084B1 (fr) 2000-05-17

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EP94420275A Expired - Lifetime EP0650084B1 (fr) 1993-10-20 1994-10-17 Emulsion d'halogénure d'argent photographique comprenant des grains à faces (100) avec des cavités

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EP (1) EP0650084B1 (fr)
DE (1) DE69424498T2 (fr)
FR (1) FR2711431B1 (fr)

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60136735A (ja) * 1983-09-05 1985-07-20 Mitsubishi Paper Mills Ltd ハロゲン化銀写真感光乳剤の製造方法
JPS60221320A (ja) * 1984-04-17 1985-11-06 Mitsubishi Paper Mills Ltd 新規なハロゲン化銀結晶及びその製造法
JPS61232444A (ja) * 1985-04-08 1986-10-16 Mitsubishi Paper Mills Ltd ハロゲン化銀写真感光材料
JPH0820690B2 (ja) * 1986-02-03 1996-03-04 コニカ株式会社 ハロゲン化銀粒子及び核ハロゲン化銀粒子を含む写真感光材料
IT1251792B (it) * 1991-07-15 1995-05-26 Minnesota Mining & Mfg Emulsione agli alogenuri d'argento comprendente granuli aventi struttura a cratere o a tramoggia e metodo per la sua preparazione.

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DE69424498D1 (de) 2000-06-21
DE69424498T2 (de) 2001-01-18
FR2711431B1 (fr) 1996-01-05
EP0650084A1 (fr) 1995-04-26
FR2711431A1 (fr) 1995-04-28

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