EP0943956A1 - Photographisches Silberhalogenidemlement mit Schutz gegen Flecken und verbessertem Empfindlichkeit/Dmin-Verhältnis - Google Patents

Photographisches Silberhalogenidemlement mit Schutz gegen Flecken und verbessertem Empfindlichkeit/Dmin-Verhältnis Download PDF

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Publication number
EP0943956A1
EP0943956A1 EP98104883A EP98104883A EP0943956A1 EP 0943956 A1 EP0943956 A1 EP 0943956A1 EP 98104883 A EP98104883 A EP 98104883A EP 98104883 A EP98104883 A EP 98104883A EP 0943956 A1 EP0943956 A1 EP 0943956A1
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EP
European Patent Office
Prior art keywords
group
silver halide
silver
polyamine
aryl compound
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EP98104883A
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English (en)
French (fr)
Inventor
Alain Dominique Sismondi
Guiseppe Loviglio
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Eastman Kodak Co
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Eastman Kodak Co
Imation Corp
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Priority to EP98104883A priority Critical patent/EP0943956A1/de
Priority to JP11072064A priority patent/JP2000066329A/ja
Publication of EP0943956A1 publication Critical patent/EP0943956A1/de
Withdrawn legal-status Critical Current

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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
    • 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
    • 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
    • G03C1/33—Spot-preventing agents
    • 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
    • G03C2200/42—Mixtures in general
    • 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
    • G03C2200/45—Polyhydroxybenzene

Definitions

  • the present invention relates to a silver halide radiographic material. More particularly, the present invention relates to the combination of a polyamine-polycarboxyl derivative and an aryl derivative in a process to prepare a silver halide emulsion to preserve the resulting photographic material from spot defects due to metallic contamination and to increase the speed to Dmin ratio thereof.
  • Silver halide emulsions are usually prepared by precipitating silver halide (silver bromide, silver iodide, silver chloride or mixture thereof) in the presence of a hydrophilic colloid (normally gelatin). Afterwards, the silver halide emulsions have to be subjected to a sensitization process for increasing their sensitivity to light.
  • the sensitization process mainly involves spectral sensitization and chemical sensitization.
  • Spectral sensitization comprises the addition of spectral sensitizing dyes which can be adsorbed on the silver halide grain surface in order to make the emulsion sensitive to visible or infrared radiation.
  • Chemical sensitization comprises the addition of various chemical substances to obtain a prescribed value of sensitivity and contrast.
  • Typical methods for chemical sensitizing a silver halide photographic emulsion include sulfur sensitization, noble metal sensitization, and reduction sensitization. It is also common in the art to have combination methods, such as sulfur-noble metal sensitization, reduction-noble metal sensitization, and the like.
  • a number of patents and patent applications, as well as literature references discloses specific methods to improve chemical sensitization. For example, Research Disclosure , September 1994, Item 36544, Paragraph IV, pp. 510-511, gives a wide array of references for each of the above-mentioned methods.
  • Another improvement area is in the preparation of silver halide elements. It is important that the silver halide elements be free from any metal contamination. However, fine metal particles are produced by the equipment which is used during the manufacturing process itself. This problem can occur during any step from the base preparation to final coating. Even if different metals like copper or nickel can be present on the final material, the main metal contaminant is constituted by fine iron particles. The presence of iron ions like Fe in oxidation state (III) can desensitize the silver halide and produce a lower density halo on the developed film creating a white spot.
  • the presence of fine metallic iron particles or iron ions like Fe in oxidation state (II) can generate, by oxidation, the release of one or two electrons, which produce sensitized halo on the developed film creating black spots.
  • white or black spot are relative terms merely meaning that the spot appear whiter or blacker than the surrounding non-contaminated area of the film.
  • spots in developed image can give bad image quality and be unacceptable in many photographic films,especially in an X-ray application where these spots can interfere with medical diagnosis.
  • One known approach for controlling or eliminating these defects is to add a sequestering or chelating agent.
  • the chemical compound gives generally a strong complex with the metal and can remove them from the photosensitive element. The final effect is effectively to prevent spot formation in silver halide photographic film.
  • US Patent 3,443,951 discloses the use of phosphoric acid esters in photographic element to prevent spot formation caused by metal particles.
  • US Patent 4,340,665 discloses the use of phosphate and amine complexing agents in synergistic combination to reduce spot formation caused by iron contamination of photographic element.
  • US Patent 3,925,086 discloses the use of azotriazoles and azotetrazoles as antispot agent in photographic silver halide emulsion or in processing baths.
  • US Patent 3,300,312 discloses the use of sulfosalicylic acid in photographic elements to reduce spotting from metallic particles.
  • EP 733,940 discloses the use of both phosphate and sulfosalicylic acid in photographic elements to reduce spotting from spurious metal particle contamination.
  • GB Patent 1,350,303 discloses the use of thienyl or furyl compound to reduced tendency to spot formation due to metal or metal oxide contamination.
  • GB Patent 1,350,302 discloses the use of aldoxime compound to reduced tendency to spot formation due to metal or metal oxide contamination.
  • US Patent 4,340,665 discloses the use of phosphate and hydroxyethylene diamine triacetate in photographic silver halide materials to reduce metal particle contamination.
  • Hydroxy substituted aryl compounds are described, for example, in the patents and patent applications described hereinbelow.
  • US 5,028,520 discloses the use of hydroquinone sulfonic acid potassium salt on tabular silver halide emulsion in an amount of from 0.03 to 0.5 moles per mole of silver to decrease the surface glossiness. It is also disclosed that no effect is obtained with amount lower than 0.03 mole per mole of silver.
  • JP 54-040729, JP 56-001936 and JP 62-021143 disclose the use of polyhydroxybenzene derivatives on cubic silver halide emulsions to decrease pressure sensitivity in graphic art films.
  • EP 452772, EP 476521, EP 482599 and EP 488029 disclose the use of polyhydroxybenzene derivatives with functional groups that allow better silver halide grain adsorption to decrease pressure sensitivity of final film.
  • EP 339870 discloses a silver halide photographic emulsion having in reactive association a sensitizing amount of polyalkylene glycol compound and a fog reducing amount of an arylhydroxy compound.
  • European Patent Application No. 97-116341.5 discloses the use of aryl derivative in a process to prepare a silver halide emulsion to improve the speed to Dmin ratio of the resulting photographic materials.
  • European Patent Application No. 97-116342.3 discloses the use of aryl derivative in a process to prepare a silver halide emulsion to preserve from spot defects due to metallic contamination the resulting photographic materials.
  • the present invention provides a process for manufacturing a silver halide photographic material comprising the step of adding to a silver halide emulsion a polyamine-polycarboxyl derivative and an aryl compound having at least two hydroxyl groups and at least one additional substituent represented by a sulfonic group, an hydroxyl group, a carboxy group or a hydroxymethyl group.
  • a silver halide photographic element comprising at least one silver halide emulsion layer coated on a support base, wherein said silver halide emulsion layer comprises a combination of a polyamine-polycarboxyl derivative and an aryl compound having at least two hydroxyl groups and at least one additional substituent represented by a sulfonic group, an hydroxyl group, a carboxy group or an hydroxymethyl group.
  • the present invention relates to the use of a combination of a polyamine-polycarboxyl derivative and an aryl compound having at least two hydroxyl groups and at least one additional substituent represented by a sulfonic group, an hydroxyl group, a carboxy group or an hydroxymethyl group to preserve from spot defects due to metallic a silver halide photographic emulsion comprising silver halide tabular grains and to increase the speed to Dmin ratio thereof.
  • the manufacturing process of silver halide elements usually comprises an emulsion-making step, a chemical and optical sensitization step, and a coating step.
  • the silver halide emulsion-making step generally comprises a nucleation step, in which silver halide grain seeds are formed, followed by one or more growing steps, in which the grain seeds achieve their final dimension, and a washing step, in which all soluble salts are removed from the final emulsion.
  • a ripening step is usually performed between the nucleation and growing step and/or between the growing and the washing steps.
  • the resulting silver halide emulsion is then coated on a proper support to prepare a silver halide photographic material.
  • a polyamine-polycarboxyl derivative and an aryl compound having at least two hydroxyl groups and at least one additional substituent represented by a sulfonic group, an hydroxyl group, a carboxy group or an hydroxymethyl group is added to the silver halide emulsion at any time before the coating of the silver halide emulsion.
  • the term "any time before the coating” means during or after the emulsion-making step, before, during or after the chemical and optical sensitization step, or just before coating.
  • the polyamine-polycarboxyl derivative and aryl compound combination is added just before coating.
  • the polyamine-polycarboxyl derivative is represented by the following formula: wherein Z is a divalent organic linking group, R 1 and R 2 , equal or different, can be a hydrogen atom, an aryl group or a -(CH 2 ) p -COOH group, and n, m, and p, equal or different, are an integer from 1 to 3.
  • divalent organic linking group Z is represented by an alkylene group of from 1 to 10 carbon atoms, an arylene group, an alkylarylene group, an aralkylene group, a cycloalkylene group, and the like.
  • alkylene group includes not only such alkyl moiety as methylene, ethylene, butylene, octylene, and the like, but also moieties bearing substituent groups such as halogen, cyano, hydroxyl, nitro, amino, carboxylate, and the like.
  • One or more carbon atoms of the divalent organic linking groups Z described above can be replaced by one or more heteroatoms such as nitrogen, sulfur, or oxygen.
  • the nitrogen atom can also be further substituted by an alkyl group having from 1 to 3 carbon atoms or a -(CH 2 ) p -COOH group.
  • the polyamine-polycarboxyl derivative is represented by the following formula: wherein Z 1 and Z 2 are represented by an alkylene chain of from 1 to 5 carbon atoms, R 1 and R 2 , equal or different, can be a hydrogen atom, an aryl group or a - (CH 2 ) p -COOH group, and n, m, and p, equal or different, are an integer from 1 to 3.
  • the addition amount of the above described polyamine-polycarboxyl derivatives is lower than 30 millimoles per mole of silver, preferably in the range of from 0.1 to 30 millimoles per mole of silver, more preferably from 1 to 30 millimoles per mole of silver, and most preferably from 5 to 30 millimoles per mole of silver.
  • the above mentioned amounts corresponds to an amount lower than 0.6, preferably in the range of from 0.002 to 0.6, more preferably from 0.02 to 0.6, and most preferably from 0.1 to 0.6 millimoles per square meter per side.
  • the aryl compound is represented by the following formula: wherein R is a sulfonic group, an hydroxyl group, a carboxy group or an hydroxymethyl group and n is an integer of from 1 to 4.
  • the aryl compound is represented by the following formula: wherein R is a sulfonic group, an hydroxyl group, a carboxy group or an hydroxymethyl group and n is an integer of from 1 to 4.
  • the aryl compound is represented by the following formula: wherein R is a sulfonic group and n is an integer of from 1 to 4.
  • the addition amount of the above described aryl compound is typically lower than 30 millimoles per mole of silver, preferably in the range of from 0.1 to 30 millimoles per mole of silver, more preferably from 1 to 30 millimoles per mole of silver, and most preferably from 5 to 30 millimoles per mole of silver.
  • the above mentioned amounts corresponds to an amount lower than 0.6, preferably in the range of from 0.002 to 0.6, more preferably from 0.02 to 0.6, and most preferably from 0.1 to 0.6 millimoles per square meter per side.
  • Silver halide emulsions useful in the present invention can be prepared using a single-jet method, a double-jet method, or a combination of these methods and can be ripened using, for instance, an ammonia method, a neutralization method, or an acid method. Parameters which may be adjusted to control grain growth include pH, pAg, temperature, shape and size of reaction vessel, and the reaction method (e.g., accelerated or constant flow rate precipitation, interrupted precipitation, ultrafiltration during precipitation, reverse mixing processes and combinations thereof).
  • a silver halide solvent such as ammonia, thioethers, thioureas, etc., may be used, if desired, for controlling grain size, grain structure, particle size distribution of the grains, and the grain-growth rate.
  • halogen compositions of the silver halide grains can be used.
  • Typical silver halides include silver chloride, silver bromide, silver iodide, silver chloroiodide, silver bromoiodide, silver chlorobromoiodide and the like.
  • silver bromide and silver bromoiodide are preferred silver halide compositions with silver bromoiodide compositions containing from 0 to 10 mol% silver iodide, preferably, from 0.2 to 5 mol% silver iodide, and more preferably, from 0.5 to 1.5 mol% silver iodide.
  • the halogen composition of individual grains may be homogeneous or heterogeneous.
  • gelatin As a binder for silver halide emulsions, gelatin is preferred, but other hydrophilic colloids can be used, alone or in combination, such as, dextran, cellulose derivatives (e.g., hydroxyethylcellulose, carboxymethyl cellulose), collagen derivatives, colloidal albumin or casein, polysaccharides, synthetic hydrophilic polymers (e.g., polyvinylpyrrolidone, polyacrylamide, polyvinylalcohol, polyvinylpyrazole) and the like.
  • Gelatin derivatives such as, highly deionized gelatin, acetylated gelatin and phthalated gelatin can also be used.
  • hydrophilic colloids in combination with synthetic polymeric binders and peptizers such as acrylamide and methacrylamide polymers, polymers of alkyl and sulfoalkyl acrylates and methacrylates, polyvinyl alcohol and its derivatives, polyvinyl lactams, polyamides, polyamines, polyvinyl acetates, and the like.
  • synthetic polymeric binders and peptizers such as acrylamide and methacrylamide polymers, polymers of alkyl and sulfoalkyl acrylates and methacrylates, polyvinyl alcohol and its derivatives, polyvinyl lactams, polyamides, polyamines, polyvinyl acetates, and the like.
  • the grains of these silver halide emulsions may be coarse or fine, and the grain size distribution of them may be narrow or extensive.
  • the silver halide grains may be regular grains having a regular crystal structure such as cube, octahedron, and tetradecahedron, or the spherical or irregular crystal structure, or those having crystal defects such as twin planes, or those having a tabular form, or combination thereof.
  • the grain structure of the silver halides may be uniform from the interior to exterior thereof, or be multilayer.
  • the grains may comprise a core and a shell, which may have different halide compositions and/or may have undergone different modifications such as the addition of doping agents.
  • the silver halide grains may also comprise different phases in-between.
  • the silver halides may be of such a type as allows a latent image to be formed mainly on the surface thereof or of such type as allows it to be formed inside the grains thereof.
  • tabular silver halide emulsions are employed.
  • Tabular silver halide emulsions are characterized by the average diameter:thickness ratio of silver halide grains (often referred to in the art as aspect ratio).
  • Tabular silver halide grains have an aspect ratio of at least 2:1, preferably, 2:1 to 20:1, more preferably, 2:1 to 14:1, and most preferably, 2:1 to 8:1.
  • Average diameters of the tabular silver halide grains range from about 0.3 to about 5 mm, preferably, from about 0.5 to about 3 mm, more preferably, from about 0.8 to about 1.5 mm.
  • the tabular silver halide grains have a thickness of less than 0.4 mm, preferably, less than 0.3 mm, and more preferably, within 0.1 to 0.3 mm.
  • the projected area of the tabular silver halide grains accounts for at least 50%, preferably, at least 80%, and more preferably, at least 90% of the projected area of all the silver halide grains of the emulsion.
  • the tabular silver halide grain dimensions and characteristics described above can be readily ascertained by procedures well known to those skilled in the art.
  • the term "diameter” is defined as the diameter of a circle having an area equal to the projected area of the grain.
  • the term “thickness” means the distance between two substantially parallel main planes constituting the tabular silver halide grains. From the measure of diameter and thickness of each grain the diameter:thickness ratio of each grain can be calculated, and the diameter:thickness ratios of all tabular grains can be averaged to obtain their average diameter:thickness ratio.
  • the average diameter:thickness ratio is the average of individual tabular grain diameter:thickness ratios. In practice, it is simpler to obtain an average diameter and an average thickness of the tabular grains and to calculate the average diameter:thickness ratio as the ratio of these two averages. Whatever the method used, the average diameter:thickness ratios obtained do not greatly differ.
  • Silver halide emulsions containing tabular silver halide grains can be prepared by various processes known to those of ordinary skill in the art for the preparation of photographic elements.
  • water soluble salts are removed from the emulsion by procedures known in the art. Suitable washing processes are those wherein the dispersing medium and soluble salts dissolved therein can be removed from the silver halide emulsion on a continuous basis, such as, for example, a combination of dialysis or electrodialysis for the removal of soluble salts or a combination of osmosis or reverse osmosis for the removal of the dispersing medium.
  • ultrafiltration is a particularly advantageous washing processes for the practice of this process.
  • an ultrafiltration unit comprising membranes of inert, non-ionic polymers is used as a washing process. Since silver halide grains are large in comparison with the dispersing medium and the soluble salts or ions, silver halide grains are retained by the membranes while the dispersing medium and the soluble salts dissolved therein are removed.
  • silver halide grain emulsions Prior to use, silver halide grain emulsions are generally fully dispersed and bulked up with gelatin or other dispersion of peptizer and subjected to any of the known methods for achieving optimum sensitivity.
  • a wide description of methods and compounds useful in chemical and optical sensitization can be found in Research Disclosure No. 38597, September 1996, "Photographic Silver Halide Emulsions, Preparations, Addenda, Systems and Processing", Items IV and 5.
  • Chemical sensitization is performed by adding chemical sensitizers and other additional compounds to the silver halide emulsion, followed by the so-called chemical ripening at high temperature for a predetermined period of time.
  • Chemical sensitization can be performed by various chemical sensitizers such as gold, sulfur, reducing agents, platinum, selenium, sulfur plus gold, and the like.
  • Tabular silver halide grains, after grain formation and desalting, are preferably chemically sensitized by at least one gold sensitizer and at least one sulfur sensitizer.
  • other compounds can be added to improve the photographic performances of the resulting silver halide emulsion, such as, for example, antifoggants, stabilizers, optical sensitizers, supersensitizers, and the like.
  • Gold sensitization is performed by adding a gold sensitizer to the emulsion and stirring the emulsion at high temperature of preferably 40°C or more for a predetermined period of time.
  • a gold sensitizer any gold compound which has an oxidation number of +1 or +3 and is normally used as gold sensitizer can be used.
  • Preferred examples of gold sensitizers are chloroauric acid, the salts thereof and gold complexes, such as those described in US 2,399,083.
  • gold sensitizers include chloroauric acid, potassium chloroaurate, auric trichloride, sodium aurithiosulfate, potassium aurithiocyanate, potassium iodoaurate, tetracyanoauric acid, 2-aurosulfobenzothiazole methochloride and ammonium aurothiocyanate.
  • Sulfur sensitization is performed by adding a sulfur sensitizer to the silver halide emulsion and stirring the emulsion at a high temperature of 40°C or more for a predetermined period of time.
  • sulfur sensitizer include thiosulfonates, thiocyanates, sulfinates, thioethers, and elemental sulfur.
  • the amounts of the gold sensitizer and the sulfur sensitizer change in accordance with the various conditions, such as activity of the gold and sulfur sensitizer, type and size of silver halide grains, temperature, pH and time of chemical ripening. These amounts, however, are preferably from 1 to 20 mg of gold sensitizer per mole of silver, and from 1 to 100 mg of sulfur sensitizer per mole of silver.
  • the temperature of chemical ripening is preferably 45°C or more, and more preferably 50°C to 80°C.
  • the pAg and pH may take arbitrary values.
  • gold and sulfur sensitizers can be added at the initial stage of chemical sensitization or at a later stage either simultaneously or at different times.
  • gold and sulfur sensitizers are added to the silver halide emulsion by their solutions in water, in a water-miscible organic solvent, such as methanol, ethanol and acetone, or as a mixture thereof.
  • a stabilizer is preferably added at any time before the addition of the sulfur sensitizer. Even if the action of the stabilizer is not yet fully understood, it is believed that it acts as a digest stabilizer and a site director for the sulfur sensitizer.
  • the stabilizer is added before the addition of sulfur chemical sensitizer in an amount of from 1 to 500 milligrams per mole of silver, preferably, from 10 to 300 milligrams per mole of silver.
  • useful stabilizers include thiazole derivatives; benzothiazole derivatives; mercapto-substituted heterocyclic compounds(e.g., mercaptotetrazoles, mercaptotriazoles, mercaptodiazoles, mercaptopyrimidines, mercaptoazoles); azaindenes, (e.g., triazaindenes and tetrazaindenes); triazoles; tetrazoles; and sulfonic and sulfinic benzene derivatives.
  • Azaindenes are preferably used, more preferably, tetraazaindenes.
  • the silver halide grain emulsion may be optically sensitized to a desired region of the visible spectrum.
  • the method for spectral sensitization is not particularly limited.
  • optical sensitization may be possible by using an optical sensitizer, including a cyanine dye, a merocyanine dye, complex cyanine and merocyanine dyes, oxonol dyes, hemioxonol dyes, styryl dyes and streptocyanine dyes, either alone or in combination.
  • Useful optical sensitizers include cyanines derived from quinoline, pyridine, isoquinoline, benzindole, oxazole, thiazole, selenazole, imidazole.
  • optical sensitizers are the dyes of the benzoxazole-, benzimidazole- and benzothiazole-carbocyanine type.
  • the addition of the spectral sensitizer is performed after the completion of chemical sensitization.
  • spectral sensitization can be performed concurrently with chemical sensitization, before chemical sensitization, or even prior to the completion of silver halide precipitation.
  • the preferential absorption of spectral sensitizing dyes on the crystallographic faces of the tabular grains allows chemical sensitization to occur selectively at unlike crystallographic surfaces of the tabular grains.
  • the spectral sensitizers produce J aggregates, if adsorbed on the surface of the silver halide grains, and a sharp absorption band (J-band) with a bathochromic shift with respect to the absorption maximum of the free dye in aqueous solution.
  • J-band sharp absorption band
  • J-band sharp absorption band
  • spectral sensitizing dye absorbed on the surface of the light-sensitive silver halide grains will vary with the quantity of the specific dye chosen as well as the size and chemical composition of the grains.
  • the maximum intensity of J-band has been obtained with silver halide grains having the above described sizes and the chemical compositions absorbed with J-band spectral sensitizing dyes in a concentration of from 25 to 100 percent or more of monolayer coverage of the total available surface area of the silver halide grains.
  • Optimum dye concentration levels can be chosen in the range of 0.5 to 20 millimoles per mole of silver halide, preferably, in the range of 2 to 10 millimoles.
  • Spectral sensitizing dyes producing J aggregates are well known in the art, as illustrated by F. M. Hamer, Cyanine Dyes and Related Compounds , John Wiley and Sons, 1964, Chapter XVII and by T. H. James, The Theory of the Photographic Process , 4th Edition, MacMillan, 1977, Chapter 8.
  • J-band exhibiting dyes are cyanine dyes.
  • Such dyes comprise two basic heterocyclic nuclei joined by a linkage of methine groups.
  • the heterocyclic nuclei preferably include fused benzene rings to enhance J aggregation.
  • the heterocyclic nuclei are preferably quinolinium, benzoxazolium, benzothiazolium, benzoselenazolium, benzimidazolium, naphthoxazolium, naphthothiazolium and naphthoselenazolium quaternary salts.
  • Suitable cyanine dyes which are joined by a methine linkage, include two basic heterocyclic nuclei, such as pyrrolidine, oxazoline, thiazoline, pyrrole, oxazole, thiazole, selenazole, tetrazole and pyridine and nuclei obtained by fusing an alicyclic hydrocarbon ring or an aromatic hydrocarbon ring to each of the above nuclei, such as indolenine, benzindolenine, indole, benzoxazole, naphthoxazole, benzothiazole, naphthothiazole, benzoselenazole, benzimidazole and quinoline.
  • nuclei can have substituents groups.
  • Suitable merocyanine dyes which are joined by a methine linkage, include a basic heterocyclic nucleus of the type described above and an acid nucleus, such as a 5- or 6-membered heterocyclic nucleus derived from barbituric acid, 2-thiobarbituric acid, rhodanine, hydantoin, 2-thiohydantoin, 4-thiohydantoin, 2-pyra-zolin-5-one, 2-isoxazolin-5-one, indan-1,3-done, cyclohexane-1-3-dione, and isoquinolin-4-one.
  • an acid nucleus such as a 5- or 6-membered heterocyclic nucleus derived from barbituric acid, 2-thiobarbituric acid, rhodanine, hydantoin, 2-thiohydantoin, 4-thiohydantoin, 2-pyra-zolin-5-one, 2-isoxazolin-5
  • the methine spectral sensitizing dyes are generally known in the art. Particular reference can be made to US Pat. Nos. 2,503,776; 2,912,329; 3,148,187; 3,397,060; 3,573,916; and 3,822,136 and FR Pat. No. 1,118,778. Also their use in photographic emulsions is very well known wherein they are used in optimum concentrations corresponding to desired values of sensitivity to fog ratios. Optimum or near optimum concentrations of spectral sensitizing dyes generally go from 10 to 500 mg per mole of silver, preferably, from 50 to 200, and more preferably, from 50 to 100.
  • Spectral sensitizing dyes can be used in combinations which result in supersensitization, i.e., spectral sensitization which is greater in a spectral region than that from any concentration of one dye alone or which would result from an additive effect of the dyes.
  • Supersensitization can be obtained with selected combinations of spectral sensitizing dyes and other addenda, such as stabilizers and antifoggants, development accelerators and inhibitors, optical brighteners, surfactants and antistatic agents, as described by Gilman, Photographic Science and Engineering , 18, pp. 418-430, 1974 and in US Pat. Nos. 2,933,390; 3,635,721; 3,743,510; 3,615,613; 3,615,641; 3,617,295; and 3,635,721.
  • additives can be added to the silver halide emulsion before or during coating, such as, stabilizers or antifoggants (i.e., azaindenes, triazoles, tetrazoles, imidazolium salts, polyhydroxy compounds and others); developing promoters (e.g., benzyl alcohol, polyoxyethylene type compounds, etc.); image stabilizers (i.e., compounds of the chromane, cumaran, bisphenol type, etc.); and lubricants (i.e., wax, higher fatty acids glycerides, higher alcohol esters of higher fatty acids, etc.).
  • stabilizers or antifoggants i.e., azaindenes, triazoles, tetrazoles, imidazolium salts, polyhydroxy compounds and others
  • developing promoters e.g., benzyl alcohol, polyoxyethylene type compounds, etc.
  • image stabilizers i.e., compounds of the chroman
  • coating aids modifiers of the permeability in the processing liquids, defoaming agents, antistatic agents and matting agents may be used.
  • Other useful additives are disclosed in Research Disclosure , Item 17643, December 1978 in Research Disclosure , Item 18431, August 1979, in Research Disclosure , Item 308119, Section IV, December 1989, and in Research Disclosure Item 36544, September 1994.
  • Suitable supports include glass, paper, polyethylene-coated paper, metals, polymeric film such as cellulose nitrate, cellulose acetate, polystyrene, polyethylene terephthalate, polyethylene, polypropylene and the like.
  • Preferred light-sensitive silver halide photographic elements are radiographic light-sensitive elements employed in X-ray imaging comprising a silver halide emulsion layer(s) coated on both surfaces of a support, preferably, a polyethylene terephthalate support.
  • the silver halide emulsions are preferably coated on the support at a silver coverage in the range of 1.5 to 3 g/m 2 per side.
  • the radiographic light-sensitive elements are associated with intensifying screens so as to be exposed to radiation emitted by the screens.
  • the screens are made of relatively thick phosphor layers which transform the X-rays into more imaging-effective radiation such as light (e.g., visible light).
  • the screens absorb a larger portion of X-rays than the light-sensitive elements do and are used to reduce the X-ray dose necessary to obtain a useful image.
  • Intensifying screens absorbing more than 25% of the total X-radiation are preferably used.
  • the phosphors can emit radiation in the ultraviolet, blue, green or red region of the visible spectrum and the silver halide emulsions are sensitized to the wavelength region of the radiation emitted by the screens. Sensitization is performed by using spectral sensitizing dyes absorbed on the surface of the silver halide grains as described above.
  • Dye underlayers are particularly useful to reduce the crossover of the double coated silver halide radiographic element.
  • Reference to well-known dye underlayer can be found in US Pat. Nos. 4,900,652; 4,855,221; 4,857,446; and 4,803,150.
  • a dye underlayer is coated on at least one side of the support, more preferably, on both sides of the support, before the coating of at least two silver halide emulsion.
  • the silver halide radiographic elements are preferably fore-hardened.
  • organic or inorganic hardeners include chrome salts (e.g., chrome alum, chromium acetate), aldehydes (e.g., formaldehyde and glutaraldehyde), isocyanate compounds (hexamethylene diisocyanate), active halogen compounds (e.g., 2,4-dichloro-6-hydroxy-s-triazine), epoxy compounds (e.g., tetramethylene glycol diglycidylether), N-methylol derivatives (e.g., dimethylolurea, methyloldimethyl hydantoin), aziridines, mucohalogeno acids (e.g., mucochloric acid), active vinyl derivatives (e.g., vinylsulfonyl and hydroxy-substituted vinylsulfonyl derivatives) and the like.
  • chrome salts e.g., chrome alum,
  • the silver halide photographic element can be exposed and processed by any conventional processing technique.
  • Any known developing agent can be added into the developer, such asdihydroxybenzenes (e.g., hydroquinone), pyrazolidones (1-phenyl-3-pyrazolidone or 4,4-dimethyl-1-phenyl-3-pyrazolidone), and aminophenols (e.g., N-methyl-p-aminophenol), alone or in combinations thereof.
  • the silver halide photographic elements are developed in a developer comprising dihydroxybenzenes as the main developing agent, and pyrazolidones and p-aminophenols as auxiliary developing agents.
  • additives can be present in the developer, such as, for example, antifoggants (e.g., benzotriazoles, indazoles, tetrazoles), silver halide solvents (e.g., thiosulfates, thiocyanates), sequestering agents (e.g., amino-polycarboxylic acids, aminopolyphosphonic acids), sulfite antioxidants, buffers, restrainers, hardeners, contrast promoting agents, surfactants, and the like.
  • Inorganic alkaline agents such as KOH, NaOH, and LiOH are added to the developer composition to obtain the desired pH which is usually higher than 10.
  • the silver halide photographic element can be processed with a fixer of a typical composition for the application required.
  • the fixing agents include thiosulfates, thiocyanates, sulfites, ammonium salts, and the like.
  • the fixer composition can comprise other well known additives, such asacid compounds (e.g., metabisulfates), buffers (e.g., carbonic acid, acetic acid), hardeners (e.g., aluminum salts), tone improving agents, and the like.
  • the exposed radiographic elements can be processed by any of the conventional processing techniques. Such processing techniques are illustrated for example in Research Disclosure , Item 17643, cited above, and Research Disclosure 36544 September 1994. Roller transport processing is particularly preferred, as illustrated in US Pat. Nos. 3,025,779; 3,515,556; 3,545,971; and 3,647,459 and in UK Patent 1,269,268. Hardening development can be undertaken, as illustrated in US Patent 3,232,761.
  • a silver bromoiodide emulsion with an average grain equivalent diameter of 1.25 micron, an average grain thickness of 0.18 micron, a COV of 37 % and 0.9 percent iodide in mole respect to the total halide ions was prepared by double jet method was employed for all examples 1 through 14.
  • the emulsion was chemically and spectrally sensitized using sulfur, gold, mercury and palladium sensitizers plus a triethyl ammonium salt of 5,5'-dichloro-9-ethyl-3,3'-di-(3-sulfopropyl) oxacarbocyanine as spectral sensitization dye.
  • the digest was performed for about 120 to 130 minutes at 60° and stabilized successively with 200 mg of potassium iodide and 1366 mg of 5-methyl-7-hydroxy-2-3-4-triazoindolizine (4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene) before chilling and kept in cold storage until needed for coating.
  • the sensitized silver halide emulsion was melted at 45°C and subjected to coating finals.
  • coating auxiliaries were added 1293 mg of calcium nitrate, 80 mg of azodicarboxylic dimorpholide, 18338 mg of polyethylacrylate (in dispersion at 20% in water plus 367 mg of lauryl sulfate), 66738 mg of dextran as gel extender, 267 mg of colanyl blue as chromatic corrector.
  • the pH was corrected to 6.3 before adding 3774 mg of SSMA copolymer (copolymer of styrene sulfonic acid and maleic anhydride).
  • the resulting silver halide emulsion was immediately coated on the two faces of blue 7 mil polyester base with a conventional antistatic top-coat containing hardening agents.
  • the coating speed was 8.3 meters per minute and the covering weight was around 2.25 g of silver per m 2 per side.
  • the resulting film sample was subjected to different test to evaluate its resistance to iron contamination and its resistance to ageing.
  • a first portion of the fresh film sample was kept 3 days at 38°C before being subjected to iron (III) contamination. This was done by applying on one side and at the rate of 23 ml per square meter a solution containing 0.2% by weight ferric sulfate Fe 2 (SO 4 ) 3 as iron source, 1% standard DGF Gel as coating auxiliary, 0.12% Triton X-100 as surfactant, 1% citric acid as chelating agent and sodium carbonate Na 2 CO 3 for pH 6.3. This solution is coated on half surface of a 10 by 28 cm sheet with a Mayer bar number ten. This method allows to ensure that a determined level of contaminant is present and to make discernible the compounds that are capable of removing defects caused by the contaminant.
  • the contaminated film was dried and exposed to white light with a standard bromograph for 3/10 of second with filter number 2.
  • the exposed films were processed through a 90 seconds dry to dry medical X-ray automatic processor type XP-515 (manufactured by Imation Corp., MN, USA) with standard chemistry (XAD 3 developer and XAF 3 fixer, both manufactured by Imation Corp., MN, USA).
  • a second and third portion of the fresh film sample were kept 3 days at 38°C and 10 days at 50°C, respectively, without any metallic contamination before being subjected to X-ray exposure using an X-ray tube at 75 kV and 300 mA for 0.06 second with a pair of TrimaxTM T8 type screens.
  • the exposed films were processed through a 90 seconds dry to dry medical X-ray automatic processor type XP-515 (manufactured by Imation Corp., MN, USA) with standard chemistry (XAD 3 developer and XAF 3 fixer, both manufactured by Imation Corp., MN, USA).
  • standard chemistry XAD 3 developer and XAF 3 fixer, both manufactured by Imation Corp., MN, USA.
  • sample 1 The procedure of sample 1 is repeated, except that during addition of coating finals, 6.24 milimole of compound 1 (2,5-dihydroxy-1 ,4-benzenedisulfonic acid dipotassium salt - HQDS, corresponding to exemplified compound A-9) is added per one mole of silver, corresponding to 90 mg of compound per square meter of coated film.
  • the iron contamination process is carried out in the same manner on the half sheet to determine the protection effect of compound 1. The results are reported in the following Table 1.
  • the example number 1 taken as control, shows the desensitizing effect of 0.12 milimole per square meter of iron (III) on our system. All speed values are measured 0.1 LogE above Dmin and the sensitivity of the control is taken as 100.
  • the photographic elements of the present invention comprising a silver halide emulsion containing in association a polyamine-polycarboxyl derivative and an aryl compound were preserved from spot defects due to metallic contamination and at the same time showed an improved speed to Dmin ratio.
EP98104883A 1998-03-18 1998-03-18 Photographisches Silberhalogenidemlement mit Schutz gegen Flecken und verbessertem Empfindlichkeit/Dmin-Verhältnis Withdrawn EP0943956A1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP98104883A EP0943956A1 (de) 1998-03-18 1998-03-18 Photographisches Silberhalogenidemlement mit Schutz gegen Flecken und verbessertem Empfindlichkeit/Dmin-Verhältnis
JP11072064A JP2000066329A (ja) 1998-03-18 1999-03-17 汚染防止保護および高い速度／Ｄｍｉｎ比を有するＸ線写真材料

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EP98104883A EP0943956A1 (de) 1998-03-18 1998-03-18 Photographisches Silberhalogenidemlement mit Schutz gegen Flecken und verbessertem Empfindlichkeit/Dmin-Verhältnis

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3236652A (en) * 1963-01-10 1966-02-22 Eastman Kodak Co Stabilized silver halide emulsions
GB1221137A (en) * 1968-08-21 1971-02-03 Ilford Ltd Photographic silver halide emulsions
GB1221138A (en) * 1968-09-21 1971-02-03 Ilford Ltd Photographic silver halide emulsions
US3778268A (en) * 1969-05-28 1973-12-11 Konishiroku Photo Ind Light-sensitive silver halide photographic material
US4618574A (en) * 1985-07-18 1986-10-21 Eastman Kodak Company High contrast photographic elements exhibiting reduced pepper fog
WO1990014615A1 (en) * 1989-05-23 1990-11-29 Eastman Kodak Company Improved method of photographic color development
EP0449563A1 (de) * 1990-03-30 1991-10-02 Konica Corporation Photographisches Silberhalogenidmaterial

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3236652A (en) * 1963-01-10 1966-02-22 Eastman Kodak Co Stabilized silver halide emulsions
GB1221137A (en) * 1968-08-21 1971-02-03 Ilford Ltd Photographic silver halide emulsions
GB1221138A (en) * 1968-09-21 1971-02-03 Ilford Ltd Photographic silver halide emulsions
US3778268A (en) * 1969-05-28 1973-12-11 Konishiroku Photo Ind Light-sensitive silver halide photographic material
US4618574A (en) * 1985-07-18 1986-10-21 Eastman Kodak Company High contrast photographic elements exhibiting reduced pepper fog
WO1990014615A1 (en) * 1989-05-23 1990-11-29 Eastman Kodak Company Improved method of photographic color development
EP0449563A1 (de) * 1990-03-30 1991-10-02 Konica Corporation Photographisches Silberhalogenidmaterial

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 79, no. 20, 19 November 1973, Columbus, Ohio, US; abstract no. 120446c, IK, CHON DU: "Photographic spot defect production by metallic impurities. IV." page 353; column l; XP002075208 *
HWAHAK KWA HWAHAK KONGOP., no. 5, 1972, S. Korea, pages 258 - 261 *

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