Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/268—Processing baths not provided for elsewhere, e.g. pre-treatment, stop, intermediate or rinse baths
• • 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
• • 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
  • G03C11/00—Auxiliary processes in photography
  • G03C11/06—Smoothing; Renovating; Roughening; Matting; Cleaning; Lubricating; Flame-retardant treatments

Definitions

• This invention relates to the protection of photographic silver images against the action of peroxides. It is known that processed silver halide emulsion photographic materials and especially microfilms are susceptible to the formation of microscopic spot blemishes when stored under adverse conditions. The defect is described in an article entitled 'Microscopic Spots in Processed Microfilm Their Nature and Prevention' published in Photographic Science and Engineering, Vol. 7, No. 5, p. 253, 1963. Oxidationreduction reactions between silver and peroxides are believed to be the cause of the defects.
• the present invention provides a solution to the problem of peroxide microspots which is simple, of low cost and permanent.
• a method of protecting silver images formed in a photographic material against attack by peroxides comprising contacting the material with a catalyst for the decomposition of hydrogen peroxide or a precursor of such a catalyst.
• finely divided, preferably colloidal, particles of the catalyst are incorporated into the photographic material during manufacture in a layer on the same side of the support as a photosensitive silver halide layer.
• the catalyst may be incorporated in any layer in an amount which does not interfere with the sensitometric properties of the material.
• the catalyst is incorporated in a layer or layers adjacent the silver halide emulsion layer
• the catalyst may be incorporated in a sublayer between the emulsion layer and the support and/or in an overlayer on the other side of the emulsion layer.
• the catalyst may comprise gold, palladium or platinum but is preferably manganese dioxide.
• Colloidal manganese dioxide may be incorporated into a photographic silver halide material in amounts of from 50 to 500mg/m 2 , preferably from 100 to 300 mg/m 2 . As indicated above it may be located in a sub-layer and/or overlay and the amounts used are preferably from 50 to 250 mg/m 2 in the sublayer and from 5 to 50 mg/m 2 in the overlayer.
• the preferred catalyst particles are colloidal.
• the size of colloidal particles may vary widely, e.g. 10 -7 - 10 -3 cm, as is known but sizes up to 500 ⁇ or even 1000 ⁇ are possible with the preferred particles being no larger than 150 ⁇ .
• the thickness of such layers may vary widely but thicknesses in the range 0.5 to 3.0 ⁇ m for the overlayer and 0.5 to 5.0 ⁇ m for the sub-layer are preferred.
• the catalyst can be coated in a hydrophilic binder over a layer already containing a silver image.
• the catalyst is present in a layer containing hydrophilic binder which is preferably gelatin, an acylated gelatin, polyvinyl alcohol or mixtures thereof.
• Photographic materials containing manganese dioxide catalyst should not be subjected to prolonged contact with acid fixer solutions containing sulphite ions as this can dissolve the catalyst and remove it from the material.
• acid fixer solutions containing sulphite ions e.g. an alkaline thiosulphate solution is therefore preferred.
• the silver image is treated with an aqueous solution of a catalyst precursor.
• the precursor is then converted to the catalyst either by a comparatively slow oxidative process involving atmospheric oxygen and/or peroxides or by a further processing step.
• the treatment with the catalyst precursor solution may, for example, take place as a final processing step or at any time after processing has otherwise been completed. Since the catalyst precursor is water-soluble any processing after its application to the photographic material will normally be avoided as this would tend to remove it.
• the preferred catalyst precursor is a watersoluble manganese (II) salt, e.g. manganous sulphate, nitrate or chloride.
• the solution preferably contains from 0.02 to 0.25, more preferably 0.025 to 0.1, moles manganese (II) salt per litre and optionally contains non-phosphate buffers to maintain the solution between pH 6.5 and 7.5.
• the time of treatment may vary widely between, for example, 1 second up to several minutes preferably from 5 to 30 seconds.
• the temperature of the treatment may also vary widely and, apart from its usual relationship with the time of treatment, is not considered critical.
• the catalyst precursor solution preferably contains a wetting agent to provide an even distribution of catalyst precursor in the photographic material and to avoid the formation of salt spots on drying. Any wetting agent may be used, e.g. an anionic, cationic or non-ionic wetting agent.
• Water-soluble compounds known to absorb strongly and stabilize filamentary silver images may also be included in the solution, for example nitrogencontaining heterocyclic compounds and thiols, e.g. imidazole and l-phenyl-5-mercaptotetrazole.
• the present invention further provides a photosensitive photographic material comprising a support bearing at least one silver halide emulsion layer which has incorporated in a layer adjacent thereto finely divided, preferably, colloidal, particles of a catalyst for the decomposition of hydrogen peroxide.
• the photographic materials protected from peroxide attack by the present invention are preferably microfilm materials but may be any photographic material, for example as described in Research Disclosure, December
• Example 2 50 mls of the above colloidal manganese dioxide solution were added to 450 mls of a 1096 gelatin solution adjusted to pH 6.5. The gelatin solution was then coated over a silver-containing gelatin layer on a polyethylene terephthalate film at the rate of 1.3 mls/sq.ft to give a MnO 2 laydown of 2.10 mg/m 2 . Acceleration tests using hydrogen peroxide as described in Henn and Wiest - Photographic Science and Engineering, Vol. 7 , Number 5, September - October 1963, page 253j failed to induce spotwise attack on such coati whereas similar control coating without manganese dioxid showed the expected spotwise attack.
• Example 2 50 mls of the above colloidal manganese dioxide solution were added to 450 mls of a 1096 gelatin solution adjusted to pH 6.5. The gelatin solution was then coated over a silver-containing gelatin layer on a polyethylene terephthalate film at the rate of 1.3 mls/s
• a photographic microfilm material was prepared by coating on a polyethylene terephthalate film base, a dye-containing anti-halation underlayer containing colloidal manganese dioxide coated at 151 mg/m 2 and gela at 1.90 g/m 2 , a fine grain negative emulsion layer and a gelatin supercoat containing colloidal manganese dioxide coated at 9 mg/m 2 and gelatin at 0.89 g/m 2 .
• Another photographic microfilm material was prepared by coating on a polyethylene terephthalate film base, a dye-containing anti-halaticn underlayer containing colloidal manganese dioxide coated at 176 mg/m 2 and gelatin at 1.90 g/m 2 , a fine grain negative emulsion layer coated at 1.77 g Ag/m 2 and a gelatin supercoat at 0.89 g/m 2 .
• the processed films were incubated at 49°C, 8496 RH in an atmosphere containing 150 ppm hydrogen peroxide for 64 hours.
• control experimental film showed severe microspot attack whilst all samples of the experimental films containing colloidal manganese dioxide in the underlayer and supercoat were unaffected. At higher peroxide concentrations (600 ppm) none of the samples showed microspot attack but the control film showed a significant loss of density after 3 days. The film, containing manganese dioxide was unaffected.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Catalysts (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

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• 1980
  • 1980-03-14 DE DE8080900467T patent/DE3061021D1/de not_active Expired
  • 1980-03-14 WO PCT/GB1980/000045 patent/WO1980001962A1/en active IP Right Grant
  • 1980-09-24 EP EP19800900467 patent/EP0025441B1/de not_active Expired

Non-Patent Citations (1)

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