EP0569075B1 - Procédé pour la fabrication de grains d'halogénure d'argent tabulaires - Google Patents

Procédé pour la fabrication de grains d'halogénure d'argent tabulaires Download PDF

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Publication number
EP0569075B1
EP0569075B1 EP19930201136 EP93201136A EP0569075B1 EP 0569075 B1 EP0569075 B1 EP 0569075B1 EP 19930201136 EP19930201136 EP 19930201136 EP 93201136 A EP93201136 A EP 93201136A EP 0569075 B1 EP0569075 B1 EP 0569075B1
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Prior art keywords
tabular grains
emulsion
grains
silver halide
tabular
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German (de)
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EP0569075A1 (fr
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Marc c/o Agfa-Gevaert N.V. Van den Zegel
Marcel c/o Agfa-Gevaert N.V. Mestdagh
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Agfa Gevaert NV
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Agfa Gevaert NV
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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
    • G03C1/0051—Tabular grain 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
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/16—X-ray, infrared, or ultraviolet ray processes
    • 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
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
    • G03C5/29—Development processes or agents therefor
    • G03C5/30—Developers

Definitions

  • This invention relates to a method of making tabular silver halide grains of intermediate thickness (0.15 to 0.30 ⁇ m), useful in forehardened coated radiographic materials.
  • Tabular silver halide grains are crystals possessing two parallel faces with a ratio between the diameter of a circle having the same area as these faces, and the thickness, being the distance between the two major faces, equal to two or more.
  • Tabular grains are known in the photographic art for quite some time. As early as 1961 Berry et al described the preparation and growth of tabular silver bromoiodide grains in Photographic Science and Engineering, Vol 5, No 6. A discussion of tabular grains appeared in Duffin, Photographic Emulsion Chemistry, Focal Press, 1966, p. 66-72. Early patent literature includes Bogg US Patent 4,063,951, Lewis US Patent 4,067,739 and Maternaghan US Patents 4,150,994; 4,184,877 and 4,184,878. However the tabular grains described herein cannot be regarded as showing a high diameter to thickness ratio, commonly termed aspect ratio. In a number of US Patent Applications filed in 1981 and issued in 1984 tabular grains with high aspect ratio and their advantages in photographic applications are described.
  • So Wilgus US Patent 4,434,226 discloses tabular silver bromoiodide grains having a thickness less than 0.2 ⁇ m, a diameter of at least 0.6 ⁇ m and an average aspect ratio greater than 8:1 and accounting for at least 50 percent of the total projected area of all the emulsion grains.
  • Kofron US Patent 4,439,520 discloses similar grains which are spectrally sensitized.
  • Abbott US Patent 4,425,425 describes radiographic materials containing tabular grains with an aspect ratio of at least 8:1 and Abbott US Patent 4,425,426 discloses similar grains with an aspect ratio between 5:1 and 8:1.
  • a survey on high aspect ratio silver halide emulsions appeared in Research Disclosure, Volume 225, Jan 1983, Item 22534.
  • tabular grains For radiographic applications the main photographic advantages of tabular grains compared to normal globular grains are a high covering power at high forehardening levels, a high developability and higher sharpness especially in double side coated spectrally sensitized materials. The thinner the tabular grains the greater these advantages.
  • tabular grains have two important disadvantages. These grains are highly susceptible to mechanical stress and the developed silver has an unacceptable reddish-brown colour compaired with the cold-black colour shown by more globular grains.
  • This reddish-brown colour can be corrected by increasing the optical density in the red region of the visible spectrum by adding suitable dyes to the undercoat layer, to the emulsion layer and/or to the protective layer. But this inevitably leads to an undesirable higher gross-fog of the photographic material and obviously the sensitivity to mechanical stress is not improved by this optical correction method.
  • a method for the preparation of an emulsion with tabular silver halide grains, wherein at least 70 % of the total projected area of all the grains is provided by said tabular grains, and wherein said tabular grains exhibit
  • 0.5 % to 5.0 % is added during the nucleation step which consists preferably of an approximately equimolecular simultaneous addition of silver nitrate and halide salts at a pBr of 1.0 to 2.0. More preferably the pBr value is situated between 1.3 and 2.0 during the nucleation step to form hexagonal or circular tabular grains. The rest of the silver nitrate and halide salts is added during consecutive double jet growth steps.
  • the different steps of the precipitation can be alternated by physical ripening steps or by so called “neutralization steps", during which the pAg value is changed to a value required in the next growth stage by adding an amount of silver nitrate solution or a water soluble halide salt within a well-defined time of addition by means of the single-jet technique.
  • Alternative ways to regulate the pAg to the desired value before continuing the processing are diluting the emulsion present in the reaction vessel, diafiltration or ultrafiltration and even flocculation and washing procedures, the last techniques being preferred to concentrate the emulsion crystals in the reaction vessel. Any combination or any choice of the mentioned techniques may be applied thereto.
  • At least two growth steps are necessary.
  • the crystal grows laterally and in the second growth step a simultaneous growth in the direction perpendicular to the main planes is induced.
  • the ratio of the second growth step to the first growth step and the pBr in this second growth step is such that the average thickness is between 0.15-0.30 ⁇ m preferably between 0.20 and 0.30 ⁇ m.
  • the average aspect ratio is then preferably less than 8, even less than 5.
  • an increasing flow rate of silver and halide solutions is preferably applied, e.g. a linearly increasing flow rate. Typically the flow rate at the end is about 3 to 0 times greater then at the start of the growth step.
  • the pBr before the start and during the different stages of the precipitation is maintained at a well-defined value as will become apparent from the examples hereinafter.
  • a wash technique in order to remove the excess of soluble salts may be applied at a pH value which can vary during washing but remains comprised between 4.0 and 7.0. If in that case the emulsion is washed by diafiltration by means of a semipermeable membrane this technique is also called ultrafiltration.
  • Such procedures are disclosed e.g. in Research Disclosure Vol. 102, Oct. 1972, Item 10208, Research Disclosure Vol. 131, March, Item 13122 and Mignot US Patent 4,334,012.
  • pH and pAg are the same as at the end of the precipitation without any adjustment.
  • dialysis techniques like ultrafiltration flocculation by polymeric reagents at a pH value below 4.0, followed by redispersion may be applied.
  • iodide ions can be incorporated in the silver halide e.g. silver bromide tabular grains of the present invention. This can be achieved by mixing a soluble bromide and a soluble iodide salt in one or more of the halide solutions up to the desired mole % concentrations required in each preparation step or by a triple jet technique, or separate addition of an iodide containing aqueous solution. Due to the lower solubility of iodide ions in comparison with bromide ions, said iodide ions are able to displace bromide ions from the grain, a technique known in the art as conversion. Iodide ions may also be incorporated into the silver halide crystal lattice by the addition of a previously prepared silver iodide micrate emulsion, composed of either pure silver iodide or mixed halides.
  • Two or more types of tabular silver halide emulsions that have been prepared differently can be mixed for forming a photographic emulsion for use in accordance with the present invention.
  • the size distribution of the tabular silver halide particles of the photographic emulsions to be prepared according to the method of the present invention can be monodisperse or heterodisperse.
  • the tabular grain emulsion becomes more heterodisperse by adding more silver nitrate during the first growth step at a pBr value lower than 1.7, said value being preferably lower than 1.2.
  • the tabular silver halide emulsions prepared according to the method of the present invention can be chemically sensitized as described e.g. in "Chimie et Physique Photographique” by P. Glafkides, in “Photographic Emulsion Chemistry” by G.F. Duffin, in “Making and Coating Photographic Emulsion” by V.L. Zelikman et al, and in "Die Grundlagen der Photographischen mit Silberhalogeniden” edited by H. Frieser and published by Akademische Verlagsgesellschaft (1968).
  • chemical sensitization can be carried out by effecting the ripening in the presence of small amounts of compounds containing sulphur e.g.
  • emulsions may be sensitized also by means of gold-sulphur ripeners or by means of reductors e.g. tin compounds as described in GB Patent 789,823, amines, hydrazine derivatives, formamidine-sulphinic acids, and silane compounds.
  • reductors e.g. tin compounds as described in GB Patent 789,823, amines, hydrazine derivatives, formamidine-sulphinic acids, and silane compounds.
  • the tabular silver halide emulsions may be spectrally sensitized with methine dyes such as those described by F.M. Hamer in "The Cyanine Dyes and Related Compounds", 1964, John Wiley & Sons.
  • Dyes that can be used for the purpose of spectral sensitization include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes.
  • Particularly valuable dyes are those belonging to the cyanine dyes, merocyanine dyes and complex merocyanine dyes.
  • Especially preferred green sensitizer in connection with the present invention are anhydro-5,5'-dichloro-3,3'-bis(n.sulfobutyl)-9-ethyloxacarbo-cyanine hydroxide and anhydro-5,5'-dichloro-3,3'-bis(n.sulfopropyl)-9-ethyloxacarbo-cyanine hydroxide.
  • spectral sensitization traditionally follows the completion of chemical sensitization. However, in connection with tabular grains, it is specifically considered that spectral sensitization may occur simultaneously with or may even precede completely the chemical sensitization step: the chemical sensitization after spectral sensitization is believed to occur at one or more ordered discrete sites of tabular grains.
  • emulsions prepared according to the method of the present invention wherein the chemical sensitization proceeds in the presence of one or more phenidone and derivatives, a dihydroxy benzene as hydroquinone, resorcinol, catechol and/or a derivative(s) therefrom, one or more stabilizer(s) or antifoggant(s), one or more spectal sensitizer(s) or combinations of said ingredients.
  • a phenidone and derivatives a dihydroxy benzene as hydroquinone, resorcinol, catechol and/or a derivative(s) therefrom, one or more stabilizer(s) or antifoggant(s), one or more spectal sensitizer(s) or combinations of said ingredients.
  • 1-p-carboxyphenyl, 4,4' dimethyl-3-pyrazolidine-1-one may be added as a preferred auxiliary agent.
  • the silver halide emulsion layer(s) having tabular grains prepared in accordance with the present invention or the non-light-sensitive layers may comprise compounds preventing the formation of fog or stabilizing the photographic characteristics during the production or storage of the photographic elements or during the photographic treatment thereof.
  • Many known compounds can be added as fog-inhibiting agent or stabilizer to the silver halide emulsion layer or to other coating layers in water-permeable relationship therewith such as an undercoat or a protective layer. Suitable examples are e.g.
  • heterocyclic nitrogen-containing compounds such as benzothiazolium salts, nitroimidazoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzothiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles, benzotriazoles (preferably 5-methyl-benzotriazole), nitrobenzotriazoles, mercaptotetrazoles, in particular
  • Additional gelatin is added in a later stage of the emulsion preparation, e.g. after washing, to establish optimal coating conditions and/or to establish the required thickness of the coated emulsion layer.
  • a gelatin / silver halide ratio ranging from 0.3 to 1.0 is then obtained.
  • the gelatin binder of the photographic elements can be forehardened with appropriate hardening agents such as those of the epoxide type, those of the ethylenimine type, those of the vinylsulfone type e.g. 1,3-vinylsulphonyl-2-propanol, chromium salts e.g. chromium acetate and chromium alum, aldehydes e.g. formaldehyde, glyoxal, and glutaraldehyde, N-methylol compounds e.g. dimethylolurea and methyloldimethylhydantoin, dioxan derivatives e.g.
  • appropriate hardening agents such as those of the epoxide type, those of the ethylenimine type, those of the vinylsulfone type e.g. 1,3-vinylsulphonyl-2-propanol, chromium salts e.g. chromium a
  • 2,3-dihydroxy-dioxan active vinyl compounds e.g. 1,3,5-triacryloyl-hexahydro-s-triazine, active halogen compounds e.g. 2,4-dichloro-6-hydroxy-s-triazine, and mucohalogenic acids e.g. mucochloric acid and mucophenoxychloric acid.
  • These hardeners can be used alone or in combination.
  • the binder can also be hardened with fast-reacting hardeners such as carbamoylpyridinium salts as disclosed in US Patent 4,063,952 and with the onium compounds as disclosed in EP Patent Application 408 143.
  • the photographic tabular grains prepared according to the method of the present invention can be used in various types of photographic elements, e.g. black and white silver halide photographic materials, like materials used for X-ray diagnostic purposes, or colour sensitive materials.
  • the photographic element may contain one single emulsion layer, as it is the case for many applications, or it can be built up by two or even more emulsion layers.
  • a material with a single or a duplitized emulsion layer coated on one or both sides of the support contains silver halide emulsions prepared according to the method of the present invention.
  • duplitized emulsions differing in photographic speed by at least 0.15 log E a gain in cross-over exposure in double side coated materials can be obtained.
  • the material contains blue, green and red sensitive layers each of which can be single coated, but merely consist of double or even triple layers.
  • the photographic material may contain several light-insensitive layers, e.g. a protective layer, one or more backing layers, one or more subbing layers, one or more intermediate layers e.g. filter layers and even an afterlayer containing e.g. the hardening agent(s), the antistatic agent(s), filter dyes for safety-light purposes etc.
  • the photographic element of the present invention may further comprise various kinds of surface-active agents in the photographic emulsion layer or in at least one other hydrophilic colloid layer.
  • Suitable surface-active agents include non-ionic agents such as saponins, alkylene oxides e.g.
  • polyethylene glycol polyethylene glycol/polypropylene glycol condensation products, polyethylene glycol alkyl ethers or polyethylene glycol alkylaryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters, polyalkylene glycol alkylamines or alkylamides, silicone-polyethylene oxide adducts, glycidol derivatives, fatty acid esters of polyhydric alcohols and alkyl esters of saccharides; anionic agents comprising an acid group such as a carboxy, sulpho, phospho, sulphuric or phosphoric ester group; ampholytic agents such as aminoacids, aminoalkyl sulphonic acids, aminoalkyl sulphates or phosphates, alkyl betaines, and amine-N-oxides; and cationic agents such as alkylamine salts, aliphatic, aromatic, or heterocyclic quaternary ammonium salts, aliphatic or heterocyclic ring
  • Such surface-active agents can be used for various purposes e.g. as coating aids, as compounds preventing electric charges, as compounds improving slidability, as compounds facilitating dispersive emulsification, as compounds preventing or reducing adhesion, and as compounds improving the photographic characteristics e.g higher contrast, sensitization, and development acceleration.
  • Preferred surface-active coating agents are compounds containing perfluorinated alkyl groups.
  • Development acceleration can be accomplished by incorporating in the emulsion layer or adjacent layers various compounds, preferably polyalkylene derivatives having a molecular weight of at least 400 such as those described in e.g. US Patents 3,038,805 - 4,038,075 and 4,292,400.
  • the photographic element of the present invention may further comprise various other additives such as e.g. compounds improving the dimensional stability of the photographic element, UV-absorbers, spacing agents and plasticizers.
  • Suitable additives for improving the dimensional stability of the photographic element are e.g. dispersions of a water-soluble or hardly soluble synthetic polymer e.g. polymers of alkyl(meth)acrylates, alkoxy(meth)acrylates, glycidyl (meth)acrylates, (meth)acrylamides, vinyl esters, acrylonitriles, olefins, and styrenes, or copolymers of the above with acrylic acids, methacrylic acids, Alpha-Beta-unsaturated dicarboxylic acids, hydroxyalkyl (meth)acrylates, sulphoalkyl (meth)acrylates, and styrene sulphonic acids.
  • a water-soluble or hardly soluble synthetic polymer e.g. polymers of alkyl(meth)acrylates, alkoxy(meth)acrylates, glycidyl (meth)acrylates, (meth)acrylamides, vinyl esters,
  • UV-absorbers are e.g. aryl-substituted benzotriazole compounds as described in US Patent 3,533,794, 4-thiazolidone compounds as described in US Patent 3,314,794 and 3,352,681, benzophenone compounds as described in JP-A 2784/71, cinnamic ester compounds as described in US Patents 3,705,805 and 3,707,375, butadiene compounds as described in US Patent 4,045,229, and benzoxazole compounds as described in US Patent 3,700,455.
  • UV-absorbers are especially useful in colour materials where they prevent the fading by light of the colour images formed after processing.
  • Spacing agents can be present of which, in general, the average particle size is comprised between 0.2 and 10 ⁇ m. Spacing agents can be soluble or insoluble in alkali. Alkali-insoluble spacing agents usually remain permanently in the photographic element, whereas alkali-soluble spacing agents usually are removed therefrom in an alkaline processing bath. Suitable spacing agents can be made e.g. of polymethyl methacrylate, of copolymers of acrylic acid and methyl methacrylate, and of hydroxypropylmethyl cellulose hexahydrophthalate. Other suitable spacing agents have been described in US Patent 4,614,708.
  • the photographic material can contain several non-light sensitive layers, e.g. an anti stress topcoat layer, one or more backing layers, and one or more intermediate layers eventually containing filter- or antihalation dyes that absorb scattering light and thus promote the image sharpness.
  • Suitable light-absorbing dyes used in these intermediate layers are described in e.g. US Patents 4,092,168, US 4,311,787, DE 2,453,217, and GB Patent 7,907,440. Situated in such an intermediate layer between the emulsion layers and the support there will be only a small negligable loss in sensitivity but in rapid processing conditions decolouration of the filter dye layers may form a problem. Therefor it should be recommended to decrease the thickness of the whole coated layer packet resulting in shorter drying times after washing in the processing cycle.
  • the use of intermediate layers situated between emulsion layer(s) and support, reflecting the fluorescent light emitted by the screens may bring a solution.
  • the addition of appropriate filter dyes to the screens may be recommended.
  • use may be made of specific dyes as MAKROLEX ORANGE G or GG, trademarked products of BAYER AG.
  • One or more backing layers can be provided at the non-light sensitive side of the support of materials coated with at least one emulsion layer at only one side of the support.
  • These layers which can serve as anti-curl layer can contain e.g. matting agents like silica particles, lubricants, antistatic agents, light absorbing dyes, opacifying agents, e.g. titanium oxide and the usual ingredients like hardeners and wetting agents.
  • the support of the photographic material may be opaque or transparent, e.g. a paper support or resin support.
  • a paper support preference is given to one coated at one or both sides with an Alpha-olefin polymer, e.g. a polyethylene layer which optionally contains an anti-halation dye or pigment.
  • an organic resin support e.g. cellulose nitrate film, cellulose acetate film, poly(vinyl acetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film, polyvinylchloride film or poly-Alpha-olefin films such as polyethylene or polypropylene film.
  • the thickness of such organic resin film is preferably comprised between 0.07 and 0.35 mm.
  • These organic resin supports are preferably coated with a subbing layer which can contain water insoluble particles such as silica or titanium dioxide.
  • the photographic material containing tabular grains prepared according to the method of the present invention can be image-wise exposed by any convenient radiation source in accordance with its specific application.
  • processing of a photographic material according to the present invention proceeds in a developing solution which contains less than 20 g, and more preferably, less than 15 g of hydroquinone per liter.
  • materials for X-ray diagnostic purposes said materials may be adapted to rapid processing conditions.
  • an automatically operating processing apparatus is used provided with a system for automatic regeneration of the processing solutions.
  • the forehardened material may be processed using one-part package chemistry or three-part package chemistry, depending on the processing application determining the degree of hardening required in said processing cycle. Applications within total processing times of 30 seconds and lower up to 90 seconds, known as common praxis, are possible. From an ecological point of view it is even possible to use sodium thiosulphate instead of ammonium thiosulphate.
  • Emulsion 1 comparative tabular emulsion
  • reaction vessel 41.3 ml of solutions 1 and 2 were introduced into a reaction vessel in 28 seconds using the double jet technique.
  • Said reaction vessel initially contained 2.16 liter of destilled water at 45°C, 12.6 grams of potassium bromide and 12.5 grams of gelatin. After one minute the reaction temperature of this mixture was raised to 70°C in 20 minutes and 47.5 grams of phthalated gelatin in 475 ml destilled water were added. After 10 minutes the neutralization step was started.
  • Emulsion 2 (invention):
  • the nucleation and the first neutralization step are the same as those used to prepare the comparative emulsion,followed by a first growth step, a second neutralization step and a second growth step.
  • a double jet precipitation was started using solutions 1 and 2 which continued for 40 minutes 51 seconds. During this precipitation, the pBr value was kept constant at 1.63. The flowing rate of solution 1 was 7.5 ml per minute at the start, linearly increasing to 26.7 ml per minute at the end of the precipitation. Thereafter the second neutralisation phaze was started.
  • Second growth step (during which 47.0 % of the total amount of AgNO 3 was used): 704 ml of solution 1 was injected in the reaction vessel at a rate of 7.5 ml per minute at the start linearly increasing to 37.5 ml per minute at the end of the precipitation.
  • the pBr was kept constant at 2.77 using solution 2 for the first 8 minutes and 51 seconds, followed by the replacement of solution 2 by solution 3 for the rest of the precipitation.
  • the tabular grain emulsion 2 corresponding to this invention, had the following characteristics, measured with electron microscopic techniques:
  • Emulsion 3 (invention).
  • a double jet precipitation was started using solutions 1 and 2 which continued for 35 minutes and 22 seconds. During this precipitation, the pBr value was kept constant at 1.63. The initial flowing rate of solution 1 of 7.5 ml per minute at the start was linearly increased to 23.9 ml per minute at the end of the precipitation. Thereafter the second neutralization step was started.
  • Second growth step (consuming 57.3 % of total amount of AgNO 3 ):
  • Emulsion 4 (invention).
  • nucleation step see nucleation step to prepare emulsion 3.
  • Neutralization step see comparative emulsion 1.
  • a double jet precipitation was started using solutions 1 and 2 which continued for 28 minutes and 39 seconds .
  • the pBr value was kept constant at a value of 1.63.
  • the flowing rate of solution 1 was 7.5 ml per minute at the start, linearly increasing to 20.8 ml per minute at the end of the precipitation. Thereafter the second neutralisation step was started.
  • Second growth step (consuming 67.5 % of the total amount of AgNO 3 ):
  • Emulsions 1 to 4 were each optimally sulphur and gold sensitized in the presence of sodium thiocyanate and anhydro-5,5'-dichloro-3,3'-bis(n.sulfobutyl)-9-ethyloxacarbo-cyanine hydroxide
  • Each emulsion was stabilized with 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene and after addition of the normal coating additives the solutions were coated simultaneously together with a protective layer containing 1.1 g gelatine per m 2 per side on both sides of a polyethylene terephthalate film support having a thickness of 175 ⁇ m.
  • the resulting photographic material contained per side an amount of silver halide corresponding to 3.5 grams of AgNO 3 per m 2 .
  • CURIX 402 (Agfa-Gevaert trade name) with the following time (in seconds (sec.)) and temperature (in °C) characteristics: loading 3.4 sec. developing 23.4 sec./ 35°C high or low activity developer cross-over 3.8 sec. fixing 15.7 sec./ 35°C in fixer AGFA G334 (trade name) cross-over 3.8 sec. rinsing 15.7 sec./ 20°C. drying 32.2 sec. (cross-over time included) total time 98.0 sec.
  • composition of the low activity developer (amounts given in grams/liter).
  • Table I summarizes the speed and contrast of the samples after processing in the high and low activity developer.
  • Speed contrast after processing in a high and low activity developer.
  • sample ( emulsion number ) % AgNO3 consumed at pBr 2.77 average thickness developer high activity low activity speed contrast speed contrast 1 (comparison) 0 0.12 100 3.70 68 2.89 2 (invention) 47.0 0.15 100 3.67 79 2.97 3 (invention) 57.3 0.17 100 3.73 83 3.13 4 (invention) 67.5 0.19 102 3.74 87 3.37
  • Emulsion 5 (invention):
  • a double jet precipitation was started using solutions 1 and 2 which continued for 35 minutes. During this precipitation, the pBr value was kept constant at 1.63. The flowing rate of solution 1 initially was 7.5 ml per minute, linearly increasing to 24.0 ml per minute at the end of the precipitation, whereafter the second neutralisation step was started.
  • Second neutralization step same as for emulsion 3.
  • Second growth step (consuming 57.2 % of the total amount of AgNO 3 ):
  • Emulsion 6 (invention):
  • a double jet precipitation was started using solutions 1 and 2 which continued for 36 minutes 44 seconds.
  • the pBr value was kept constant at 1.34.
  • the flowing rate of solution 1 was 7.5 ml per minute at the start, linearly increasing to 24.2 ml per minute at the end of the precipitation. Thereafter the second neutralization step was started.
  • Second growth step (consuming 54.1 % of total amount of AgNO 3 ):
  • Emulsion 7 (invention)
  • Second growth step (in this step 57 % of total amount of AgNO 3 was consumed):
  • solution 1 854.8 ml of solution 1 was injected in the reaction vessel at a rate of 7.5 ml per minute at the start linearly increasing to 37.5 ml per minute at the end of the precipitation.
  • the pBr value was kept constant at 3.5 using solution 2 for the first 17 minutes and 37 seconds, followed by the replacement of solution 2 by solution 3 for the rest of the precipitation time.
  • Emulsion 8 is a diagrammatic representation of Emulsion 8:
  • Second growth step (consuming 53.9 % of the total amount of AgNO 3 ):
  • Table II shows that this speed ratio is clearly lower for the emulsions according to the invention than for the comparative emulsion 1. It is also demonstrated that the pBr value of the first and the second growth step can be varied within large margins without loosing said effect on developability obtained in this invention.

Claims (13)

  1. Un procédé pour la préparation d'une émulsion à grains d'halogénure d'argent, dans lequel au moins 70% de la superficie totale projetée de tous les grains est recouvert de grains tabulaires et dans lequel les grains tabulaires présentent
    un rapport d'aspect moyen d'au moins 2:1,
    une épaisseur moyenne comprise entre 0,15 et 0,30 µm, et
    un coefficient de variation des grains tabulaires compris entre 0,15 et 0,45,
    le procédé comprenant les étapes ci-après :
    la préparation d'un milieu de dispersion contenant un peptisant à gélatine et dont le pBr est ajusté à une valeur comprise entre 1,0 et 2,0 à l'aide d'un sel fournissant des ions bromure,
    une phase de formation de germes de cristal consommant moins de 10% en poids de la quantité totale utilisée de nitrate d'argent,
    une première phase de croissance de cristal à double jet, dans laquelle au moins 10% de la quantité totale de nitrate d'argent est précipité à une valeur pBr constante comprise entre 1,0 et 2,5, et
    une seconde phase de croissance de cristal à double jet, dans laquelle au moins 40% de la quantité totale du nitrate d'argent est ajouté à une valeur pBr constante supérieure à 2,7.
  2. Procédé selon la revendication 1, caractérisé en ce qu'on n'utilise pas d'ammoniac, ajouté intentionnellement ou généré in-situ, lors de la phase de formation de germes ou la (les) phase(s) de croissance dans la préparation des grains d'halogénure d'argent tabulaires.
  3. Procédé selon la revendication 1 ou 2, caractérisé en ce que le pBr est compris entre 1,3 et 2,0 pendant la phase de formation de germes afin de former des grains tabulaires hexagonaux ou circulaires.
  4. Procédé selon l'une quelconque des revendications 1 à 3, caractérisé en ce que le coefficient de variation des grains tabulaires est compris entre 0,20 et 0,45.
  5. Procédé selon l'une quelconque des revendications 1 à 4, caractérisé en ce que le coefficient de variation des grains tabulaires est compris entre 0,30 et 0,45.
  6. Procédé selon l'une quelconque des revendications 1 à 5, caractérisé en ce que l'épaisseur moyenne des grains tabulaires est comprise entre 0,20 et 0,30 µm.
  7. Procédé selon l'une quelconque des revendications 1 à 6, caractérisé en ce que le rapport d'aspect des grains tabulaires est inférieur à 8,0.
  8. Procédé selon l'une quelconque des revendications 1 à 6, caractérisé en ce que le rapport d'aspect des grains tabulaires est inférieur à 5,0.
  9. Procédé selon l'une quelconque des revendications 1 à 8, caractérisé en ce que les cristaux d'émulsion à l'halogénure d'argent sont des cristaux de bromoiodure d'argent contenant des quantité d'ions iodure jusqu'à 3 moles %.
  10. Matériau photographique comprenant un support et au moins une couche d'émulsion à l'halogénure d'argent sur au moins un côté de ce support, cette (ces) couche(s) étant appliquée(s) à partir d'une émulsion contenant des grains d'émulsion à l'halogénure d'argent tabulaires préparés d'après le procédé selon l'une quelconque des revendications 1 à 9.
  11. Matériau photographique selon la revendication 10, caractérisé en ce que le matériau photographique est un matériau radiographique émulsionné sur un ou deux côtés.
  12. Procédé pour le traitement d'un matériau photographique selon la revendication 10 ou 11, caractérisé en ce que le traitement s'effectue dans une solution révélatrice contenant moins de 20 g d'hydroquinone par litre.
  13. Procédé pour le traitement d'un matériau photographique selon la revendication 10 ou 11, caractérisé en ce que le traitement s'effectue dans une solution révélatrice contenant moins de 15 g d'hydroquinone par litre.
EP19930201136 1992-05-05 1993-04-20 Procédé pour la fabrication de grains d'halogénure d'argent tabulaires Expired - Lifetime EP0569075B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP19930201136 EP0569075B1 (fr) 1992-05-05 1993-04-20 Procédé pour la fabrication de grains d'halogénure d'argent tabulaires

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EP92201259 1992-05-05
EP92201259 1992-05-05
EP19930201136 EP0569075B1 (fr) 1992-05-05 1993-04-20 Procédé pour la fabrication de grains d'halogénure d'argent tabulaires

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EP0569075A1 EP0569075A1 (fr) 1993-11-10
EP0569075B1 true EP0569075B1 (fr) 1998-03-25

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6878512B2 (en) 2002-10-31 2005-04-12 Ferrania, S.P.A. Silver halide tabular grain emulsion

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69519154T2 (de) * 1995-03-29 2001-04-05 Eastman Kodak Co A New Jersey Verfahren zur Herstellung von Emulsionen mit monodispersen Silberhalogenidtafelkörnern
DE69518502T2 (de) * 1995-03-29 2001-04-19 Tulalip Consultoria Com Socied Verfahren zur Herstellung von Emulsionen mit monodispersen Silberhalogenidtafelkörnern
EP0790526B1 (fr) 1996-02-19 2002-07-24 Agfa-Gevaert Système pellicule-écran formant image radiographique

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62151840A (ja) * 1985-12-26 1987-07-06 Fuji Photo Film Co Ltd 高アスペクト比のヨウ臭化銀乳剤の調製方法
DE69122717T2 (de) * 1990-05-14 1997-05-07 Eastman Kodak Co Fotografische filme enthaltend silberhalogenidkörner mit geringen zwillingsebenenabständen

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6878512B2 (en) 2002-10-31 2005-04-12 Ferrania, S.P.A. Silver halide tabular grain emulsion

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