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
  • G03C5/29—Development processes or agents therefor
  • G03C5/305—Additives other than developers
• • 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

• the present invention relates to photographic developers and more particularly to ascorbic acid developers showing improved stability.
• Examples of such developers and corresponding appropriate photographic materials include the GRANDEX system, marketed by FUJI PHOTO Ltd, AGFASTAR, marketed by ADFA-GEVAERT N.V. and the ULTRATEC system, marketed by EASTMAN KODAK Co.
• a class of developing agents which can be concerned in this connection is formed by ascorbic acid and analogous compounds.
• the active developing species are likely to be the mono- and dianion of ascorbic acid as was described by Willis and Pontius in Phot. Sci . Eng . Vol. 14 (6), p. 384 (1970), and their concentration is pH dependent.
• the ascorbic acid molecule is broken down to oxidation products, a.o. oxalic acid, showing a higher acidity. In this way the concentration of the active developing agent and the pH are both lowered. It can be expected that ascorbic acid analogues will show similar oxidation reactions.
• the objects of the present invention are realized by providing a silver halide developing solution characterized by a pH of at least 12.0 and containing :
• Preferred sugar derivatives corresponding to general formula (I) are l-ascorbic acid and iso-ascorbic acid.
• Preferred hydroxy-substituted aromatic carboxylic acids corresponding to general formula (II) for use in accordance with the present invention include :
• the most preferred hydroxy-substituted aromatic carboxylic acid for use in accordance with the present invention is salicylic acid.
• the hydroxy-substituted aromatic carboxylic acid is preferably present in the developing solution in a concentration ranging from 0.05 mole/liter to 0.7 mole/liter.
• sugar derivatives serving as developing agents in the practice of this invention are preferaby present in a concentration ranging from 0.45 to 0.90 moles per liter.
• preferred compounds for application in the present invention are l-ascorbic acid and iso-ascorbic acid.
• Other useful analogous compounds include imino-l-ascorbic acid, 6-desoxy-l-ascorbic acid, l-rhamnoascorbic acid, l-fucoascorbic acid, d-glucoheptoascorbic acid, d-glucoascorbic acid and l-erythroascorbic acid.
• These compounds can be dissolved into the developing solution in their free acid form ; alternatively they can be incorporated as alkali salt, preferably the sodium or potassium salt or a mixture of both. In case of the latter method a lower amount of alkali hydroxide is needed to establish a pH of at least 12.0.
• an alkali bromide salt e.g. potassium bromide is present in the developing solution preferably in a concentration ranging from 0.05 moles to 0.8 moles per liter and most preferably in a range from 0.1 to 0.4 moles per liter.
• At least one so-called antifogging agent or stabilizer is present in the developing solution.
• the antifogging agent is a mercapto-group containing heterocyclic substance and most preferably it is 1-phenyl-5-mercapto-tetrazole in a concentration range from 10 mg/l to 1 g/l and most preferably in a range from 20 to 250 mg/l.
• the rather high pH values in connection with the present invention can be established by means of conventional buffering agents but preferably for ecological reasons the pH is simply established by the presence of an alkali hydroxide, e.g. sodium or potassium hydroxide.
• an alkali hydroxide e.g. sodium or potassium hydroxide.
• the full benefits of this invention are obtained in a pH range from 12.3 to 13.5.
• addenda examples include complexing agents for calcium and magnesium ions, present in hard water, e.g. ethylene diamine tetraacetic acid and analogues compounds. Further can be present anti-foaming agents, surface-active agents, biocides, thickening agents like polystyrene sulphonate and antioxidants like benzoate and cyclodextrine.
• the developing liquid can contain so-called anti-sludge agents in order to reduce dirt streaks on developed photographic material.
• the solution can contain development accelerating agents like polyalkyleneoxides and alkonolamines and hardening agents including latent hardeners.
• the developing solutions of the present invention can be employed to develop various types of photographic black-and-white materials, e.g. amateur and professional materials for still photography, radiographic recording and duplicating materials, cinematographic recording and duplicating materials, and microfilm.
• photographic black-and-white materials e.g. amateur and professional materials for still photography, radiographic recording and duplicating materials, cinematographic recording and duplicating materials, and microfilm.
• merits of the present invention become most obvious in developing camera or duplicating materials for graphic arts in view of the importance of exact reproduction of line edge and screen dot originals.
• the emulsions present in these photographic materials can be of any halide composition, e.g. bromide, chloride, chlorobromide, iodobromide and chloroiodobromide emulsions.
• the emulsions can belong to the negative working type or to the direct positive type, e.g. the externally fogged type or the unfogged type requiring a fogging agent in the material or in the developing solution. The best results are obtained however when applicating the developing solutions of the invention on materials containing negative chlorobromide emulsions as is commonly the case in various types of graphic arts materials.
• the photographic elements which can be developed by the liquids of the present invention can be composed of one single emulsion layer, as it is the case for many applications, or they can be built up by two or even more emulsion layers. Beside the light sensitive emulsion layer(s) the photographic material can contain several non-light sensitive layers, e.g. a protective layer, one or more backing layers, one or more subbing layers, and one or more intermediate layers, e.g. filter layers.
• non-light sensitive layers e.g. a protective layer, one or more backing layers, one or more subbing layers, and one or more intermediate layers, e.g. filter layers.
• the emulsions present in the photographic materials which can be developed by the solutions 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 Sawe 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 can be sensitized also by means of gold-sulphur ripeners or by means of reductors e.g. tin compounds as described in GB 789,823, amines, hydrazine derivatives, formamidine-sulphinic acids, and silane compounds.
• reductors e.g. tin compounds as described in GB 789,823, amines, hydrazine derivatives, formamidine-sulphinic acids, and silane compounds.
• the silver halide emulsions can 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. Infra-red sensitizing dyes and combinations with supersensitizing compounds can be present.
• the silver halide emulsions can be stabilized by representatives of the same chemical classes which can be present in the developing solutions.
• Preferred compounds include triazaindenes, tetrazaindenes and pentazaindenes, especially those described by Birr in Z. Wiss. Phot. 47 (1952), pages 2-58.
• gelatin binder of these photographic elements can be hardened 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 acetate and
• the photographic elements under consideration may further comprise various kinds of surface-active agents in the photographic emulsion layer or in at least one other hydrophilic colloid layer.
• Preferred surface-active coating agents are compounds containing perfluorinated alkyl groups.
• the photographic elements 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.
• the photographic material can contain several non light sensitive layers, e.g. an anti-stress top 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 are described in e.g. US 4,092,168, US 4,311,787, DE 2,453,217, and GB 7 907 440.
• One or more backing layers can be provided at the non-light sensitive 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, polyvinylacetal film, polystyrene film, polyethylene 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 to be developed by the solutions of the present invention can be image-wise exposed by any convenient radiation source in accordance with its specific application.
• an automatically operating apparatus is used provided with a system for automatic replenishment of the processing solutions.
• the development step can be followed by a washing step, a fixing solution and another washing or stabilization step. Finally the photographic material is dried.
• the first washing step can be omitted if wanted.
• a developing solution consisting of : sodium iso-ascorbate.H2O 100 g potassium bromide 30 g 1-phenyl-5-mercaptotetrazole 70 mg water to make 1 l pH adjusted to 12.7 with KOH
• a silver halide emulsion containing 83.6 % of chloride, 16 % of bromide and 0.4 % of iodide was prepared by a double jet technique.
• the emulsion contained 0.1 ppm of Rhodium per mole of silver halide.
• the average grain size was 0.27 micron.
• the emulsion was chemically sensitized with ammonium gold(III) thiocyanate and sodium thiosulphate, stabilized with 4-hydroxy-6-methyl-(1,3,3a,7)-tetraazaindene and spectrally sensitized to the blue and green spectral region.
• the emulsion was coated onto a subbed polyethylene terephtalate support at a gelatin coverage of 3.1 g per m2, and a coverage of silver halide equivalent to 4.0 g of silver per m2.
• a protective layer was applied containing formaldehyde-hardened gelatin at a coverage of 1 g per m2.
• Samples of the thus prepared material were contact exposed in a KLIMSCH VACUPRINT 65 S through a continuous tone wedge.
• the exposed samples were processed for 30 s at 30 °C in developers 1 and 9 of example 1, containing no salicylic acid and 0.36 mole of salicylic acid respectively. After development the samples were fixed, washed and dried.
• the sensitometric results are represented in table 3.
• the photographic speed is expressed in relative arithmetic values (rel. S) measured at density 3.0 above fog wherein the value of the comparison is arbitrarely set to 100: higher number means higher sensitivity.
• Gradient values in the toe (g t ) were measured between densities 0.1 and 0.6 above fog.
• Straight line gradients (grad) were determined between densities 0.3 and 3.0 above fog.
• Gradient values in the shoulder (g s ) were measured between densities 3.0 and 3.8 above fog.
• the difference between the highest and lowest sensitivity value is taken as a measure for the short term stability of the developers.
• the sensitivity is measured at density 3.0 above fog and is expressed as a relative logarithmic value.
• a RAPILINE 66 processing machine was filled with the respective developers of example 3. During a period of 30 days 4 sq.m of the photographic material described in example 3 were fully exposed and processed each day. For replenishment 2000 ml developer per day and an additional 250 ml per sq.m. were added.

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• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

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Cited By (9)

Citations (6)

• 1991
  • 1991-09-12 EP EP19910202333 patent/EP0531582B1/de not_active Expired - Lifetime
  • 1991-09-12 DE DE1991624237 patent/DE69124237T2/de not_active Expired - Fee Related
• 1992
  • 1992-09-10 JP JP26934892A patent/JPH05210220A/ja active Pending

Patent Citations (6)

Non-Patent Citations (1)

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