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
  • 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
  • G03C1/34—Fog-inhibitors; Stabilisers; Agents inhibiting latent image regression
  • G03C1/346—Organic derivatives of bivalent sulfur, selenium or tellurium

Definitions

• the present invention relates to photographic recording materials and more particularly to photographic recording materials having latent image keeping stability.
• a visible image is formed in silver halide photographic materials by exposure of the material to actinic radiation to form a record of the exposure. This record, which is invisible to the unaided eye, yields a visible image by photographic processing of the exposed material.
• the latent image comprises minute specks of metallic silver. These specks form in or on individual silver halide grains by interaction between silver ions and photoelectrons generated by absorption of actinic radiation by the silver halide grains.
• Processing of most common silver halide photographic materials includes a development step in which the material is contacted with an aqueous alkaline solution of a developing agent.
• the developing agent which is a reducing agent, selectively reduces to metallic silver those silver halide grains containing a latent image.
• latent image is not permanent and that, with passage of time, silver halide grains which would be developable immediately after exposure become nondevelopable. This phenomenon is termed latent image fading and manifests itself as a loss in image density in the developed-image and a consequent loss in speed in the silver halide photographic material.
• latent image fading would not be a problem.
• delays between exposure and processing frequently occur.
• latent image fading can present a significant problem and compounds are added to photographic materials to prevent or reduce this undesirable effect.
• These compounds are referred to as latent image stabilizers and prevention or reduction of latent image fading is referred to as latent image stabilization.
• R1 is alkyl or alkoxy
• the length of the carbon chain which designates “lower” is from 1 to about 5 carbon atoms, preferably from 1 to about 3 carbon atoms.
• the alkyl or alkoxy group can be straight or branched chain.
• R1 is halogen it is preferably chloro.
• the counterbalancing ion Y can be any anion compatible with the photographic material in which it is coated.
• Useful ions include inorganic anions such as halides, halophosphates, trifluoromethane sulfon­ates and the like.
• n can be an integer as high as 6, it is at least 2 and preferably from 2 to 5.
• the carbon chain can be straight or branched chain, such as for example n-propyl, s-butyl or t-amyl.
• the alkylene group which is bonded directly to the quaternary nitrogen atom, and which is also linked to the terminal ethylene or methyl group, comprises at least 2 and as many as 6 carbon atoms. Such substitution on the nitrogen atom of the indicated quaternary salts provides latent image stability for the photographic recording materials in which they are coated.
• Compounds useful in this invention can be prepared for example by treating alcohol with trifluoromethanesulfonic anhydridide in the presence of pyridine and subsequently treating the product with benzothiazole under a nitrogen environment to produce the desired salt.
• the reaction mixture was then stirred at 0°C for 10 more minutes.
• the reaction mixture was quickly filtered through a pad of sodium sulfate.
• the filtrate was immediately added to a solution of benzothiazole (1.10 g, 0.008 mole) in dichloromethane (50 ml).
• the resulting solution was stirred at room temperature under a nitrogen atmosphere for 19 hours.
• the solvent was removed on a rotary evaporator to give a pink oil. This oil was then dissolved in warm water (50 ml). Sodium hexafluoro­phosphate (1.5 g) was added with stirring. A white precipitate immediately formed.
• the aqueous mixture was stirred at room temperature for 30 minutes, and then was filtered.
• the benzothiazolium and benzoselenazolium salts described herein can be added to a silver halide emulsion at any point subsequent to precipitation of the silver halide grains.
• the salts are added to an emulsion after chemical and spectral sensitization, but prior to coating.
• the salts can be present during these sensitization procedures.
• benzothiazolium salt added to an emulsion will depend upon various factors such as the particular salt employed, the particular silver halide emulsion used or the nature of other components of the emulsion. Useful amounts are within the range of from about 0.002 to about 10 millimoles of salt per mole of silver. Preferably, the salt is incorporated in the emulsion in an amount of from about 0.02 to about 0.5 millimole per mole of silver.
• the silver halide emulsions employed in the present invention can be any of the silver halide emulsions known in the art which are desirably protected against latent image instability or fading.
• the silver halide emulsions can be comprised of silver bromide, silver chloride, silver chloro­bromide, silver chloroiodide, silver bromoiodide, silver chlorobromoiodide or mixtures thereof.
• the emulsions can include coarse, medium or fine grains and can be monodisperse or polydisperse.
• the silver halide emulsions are preferably surface latent image-forming emulsions. They can be chemically sensitized as illustrated by T. H. James, The Theory of the Photographic Process, 4th Ed., Macmillan, 1977, pp. 67-76, or with sulfur, selenium, tellurium, gold, platinum, palladium, iridium, osmium, rhenium or phosphorus sensitizers, or combinations of these sensitizers, as illustrated by Research Disclosure, Vol. 134, June 1975, Item 13452, or in U. S. Patent Nos.
• Chemical sensitization can optionally be conducted in the presence of thiocyanate derivatives, as described in U. S. Patent Nos. 2,222,264 and 2,642,361; thioether compounds, as disclosed in U. S. Patent Nos. 2,521,926; 3,021,215 and 4,054,457; or azaindenes, azapyridazines and azapyrimidines, as described in U. S. Patent Nos. 3,411,914; 3,554,757; 3,565,631 and 3,901,714.
• the emulsions can be reduction sensitized e.g., with hydrogen, as illustrated by U. S. Patent Nos.
• the silver halide emulsions can be spectrally sensitized with dyes from a variety of classes, including the polymethine dye class, which includes the cyanines, merocyanines, complex cyanines and merocyanines (i.e., tri-, tetra-, and poly-nuclear cyanines and merocyanines), oxonols, hemioxonols, styryls, merostyryls and streptocyanines.
• Particularly useful dyes are benzoxazole, benzimidazole and benzothiazole carbocyanine dyes.
• the photographic silver halide emulsions can contain various colloids alone or in combination as vehicles. Suitable hydrophilic materials as well as hardeners therefore, are described in Research Disclosure, December 1978, Item 17643, Sections IX and X.
• the photographic silver halide emulsions and elements employing the stabilizing agents of this invention can contain other addenda conventional in the photographic art.
• Useful addenda are described, for example, in Research Disclosure, December 1978, Item 17643 and include antifoggants, couplers (such as dye forming couplers, masking couplers and DIR couplers) DIR compounds, anti-stain agents, image dye stabilizers, absorbing materials such as filter dyes and UV absorbers, light scattering materials, coating aids, plasticizers and lubricants.
• the photographic recording materials described herein can be black-and-white or monochrome materials or they can be multilayer and/or multicolor elements comprising a support bearing one or more layers of a silver halide emulsion. These materials can be designed for processing in conventional developer solutions.
• Multicolor elements can contain dye image forming units sensitive to each of the three primary regions of the spectrum. Each unit can be comprised of a single emulsion layer or of multiple emulsion layers sensitive to a given region of the spectrum.
• the layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art.
• the emulsion or emulsions can be disposed as one or more segmented layers.
• a preferred color photographic recording material comprises a support bearing at least one blue-sensitive silver halide emulsion layer having associated therewith a yellow dye-forming coupler, at least one green-­sensitive silver halide emulsion layer having associated therewith a magenta dye-forming coupler and at least one red-sensitive silver halide emulsion layer having associated therewith a cyan dye-forming coupler, at least one of the silver halide emulsion layers containing a latent image stabilizing compound of this invention.
• the stabilizing compound is contained in a yellow dye-forming blue-sensitive silver halide emulsion.
• the photographic recording materials of the present invention can contain additional layers conventional in photographic elements, such as overcoat layers, spacer layers, filter layers, antihalation layers, scavenger layers and the like.
• the support can be any suitable support used with photographic elements. Typical supports incude polymeric films, paper (including polymer-coated paper), glass and the like. Details regarding supports and other layers of the photographic elements of this invention are contained in Research Disclosure, December 1978, Item 17643, referred to above.
• the term "associated therewith” signifies that the stabilizing compound is in a silver halide emulsion layer or in an adjacent layer so that the materials contained therein are accessible to one another.
• Benzothiazolium salts as latent image keeping agents were evaluated in a black-and-white photographic test. This test used sulfur and gold sensitized 0.8 ⁇ m octahedral silver bromide emulsion prepared in the presence of 1,10-dithia-18-­crown-6 ether and bis(2-amino-5-iodopyridine-di­hydroiodide) mercuric iodide. This emulsion was coated in a single layer format. The melt pH was 5.6 and the pAg was 8.5. All the benzothiazolium salts were coated at 0.2 mmole/mole Ag.
• the latent image keeping (LIK) coatings were exposed for 1/50 sec and were then incubated at 49°C/50% RH for two weeks.
• the raw stock keeping (RSK) coatings were incubated first, followed by exposure as described above. Both coatings were processed for 6 minutes in KODAK Rapid X-ray Developer.

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

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Citations (4)

• 1990
  • 1990-07-24 JP JP19412390A patent/JPH0365946A/ja active Pending
  • 1990-07-26 EP EP90308201A patent/EP0410753A1/fr not_active Withdrawn

Patent Citations (5)

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