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
  • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
  • G03C1/825—Photosensitive materials characterised by the base or auxiliary layers characterised by antireflection means or visible-light filtering means, e.g. antihalation
  • G03C1/83—Organic dyestuffs therefor
  • G03C1/832—Methine or polymethine dyes

Definitions

• This invention relates to the processing of photographic colour negative films.
• Photographic colour materials which typically have emulsion layers sensitised to the red, green and blue regions of the spectrum need an antihalation layer which absorbs in all three regions.
• Colour films are able to use a grey metallic silver layer as an antihalation layer (type 1 above) because it will be removed during processing in the bleach and fix baths. This is convenient because silver absorbs fairly uniformly across the spectrum. All commercially available colour negative films use such a grey silver antihalation layer.
• US Patent 4 092 168 discloses the use of dyes of the type used in the present invention, for use in antihalation layers in black and white photographic materials. This is said to be an improvement over the previous practice of using a mixture of dyes to allow absorption across the whole visible spectrum.
• the specific disclosure is of an antihalation backing layer covered with an anticurl layer. The dye is removed from the film during processing. It is noted that a grey silver antihalation layer cannot be removed from black and white materials in the bleach because the bleach bath would not only bleach the antihalation layer but also the silver image.
• US Patent 4 855 221 describes the use of solid particle dispersions of certain oxonol dyes (preferred for use in the present invention) as filter layers in photographic materials. Multicolour photographic elements are mentioned but no photosensitive materials are actually exemplified.
• a method of processing an imagewise exposed photographic multilayer colour negative film comprising at least three silver halide differently sensitised emulsion layers having associated respectively therewith different dye image-forming couplers and having between the emulsion layers and the support a silver-containing antihalation layer, comprising at least the steps of colour development, bleaching and fixing characterised in that the chemical load on the bleach bath is reduced by using a dye-containing, silver-free layer which is destroyed or otherwise removed during photographic processing as the sole antihalation layer in the film.
• the present invention will usually also reduce the chemical load on the fix solution as well.
• the reduction in chemical load may be achieved in a number of ways. For example, the rate of replenishment of the bleach and fix baths may be reduced. Alternatively the concentration of the two baths may be reduced or the time of processing may be reduced.
• the present invention has the advantage of reducing the chemical load on the bleach and usually the fix bath as well.
• the advantage may be taken as lower replenishment rates, lower concentrations of active ingredients, faster processing times or combinations thereof.
• the quantity of effluent is also reduced.
• the presence in colour negative films of a grey silver layer (in its bleached form) can provide a catalyst for the formation of silver iodide (which is very difficult to fix out) at the latter part of the fix process thereby making the fix step take a longer time. This problem is also avoided.
• the bleach solution oxidises metallic silver to a silver salt.
• the oxidising (or bleaching) agent may comprise iron(III), for example in the form of an alkali metal ferricyanide, permanganate, dichromate, ferric ethylenediamine-tetraacetic acid, ferric propylenediamine-tetraacetic acid, or hydrogen peroxide.
• iron(III) for example in the form of an alkali metal ferricyanide, permanganate, dichromate, ferric ethylenediamine-tetraacetic acid, ferric propylenediamine-tetraacetic acid, or hydrogen peroxide.
• the fixer may comprise an alkali metal or ammonium thiosulphate or thiocyanate as fixing agent or, in the case of low silver coating weight materials comprising silver chloride, and alkali metal sulphite. Again fix baths are well known and are described in "Modern Photographic Processing" above.
• the bleach and the fix baths may be combined into a single bleach-fix bath and these are also described in "Modern Photographic Processing" above.
• processing solutions are replenished to replace active ingredients used up during processing or which are destroyed by chemical reaction either during processing or when standing idle, for example by aerial oxidation.
• replenishment techniques and solutions are well understood.
• the dye is preferably an oxonol dye. Such dyes are bleached by the sulphite ions in the developer solution.
• the dye has the general formula: wherein R1 to R4 are each individually hydrogen, halogen or an alkyl, aryl, heterocyclic, R5X-, R5X-NR6-, R5R6N-X- any of which may be further substituted, -COOH OR SO3H, wherein X is CO or SO2 and R5 and R6 are alkyl, aryl or heterocyclic groups which can be further substituted, and n is 0 to 3.
• the dyes of formula I and II may be coated as solutions or solid dye dispersions.
• the present colour films preferably comprise a yellow dye image-forming unit comprised of at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler, at least one magenta dye image-forming unit comprising at least one green-sensitive silver halide emulsion layer having associated therewith at least one magenta dye-forming coupler at least one cyan dye image-forming unit comprising at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler, said image-forming units being carried on a support.
• the couplers, emulsions, additives, supports, structure, etc of the present colour films may be any of those described in Research Disclosure Item 308119, December 1989 published by Kenneth Mason Publications, Emsworth, Hants, United Kingdom.
• the invention is illustrated by the following Example.
• a standard full colour photographic negative film was coated with modification to the anti-halation layer, which was coated on top of subbed base over which was coated the remainder of the film.
• the antihalation layer either contained the usual grey silver with silver levels varied, a dye of Formula II, as a replacement for the grey silver, also coated at different levels.
• a plain gelatin layer was also coated with each set as a control.
• the bleaching time was monitored by measuring the infra-red density of the film continuously while in the bleach. The time at which the density had ceased to change was taken as the bleach time.
• Table 1 shows the bleaching times and sharpnesses, measured as AMT numbers (the bigger, the sharper) of the coatings in both 35mm and Disc film formats.
• Table 1 AHU type Silver or Dye Laydown (g/m ⁇ 2) Bleach Time (secs) Fix Time (secs) AMT 35mm Disc Gel - 72 ⁇ 5 42 91.8 82.9 Gel+Ag 0.1 77 ⁇ 5 44 94.3 85.7 0.2 80 ⁇ 5 46 94.1 85.1 0.3 99 ⁇ 5 47 93.6 84.8 0.4 140 ⁇ 5 50 92.9 83.9 Gel - 61 ⁇ 5 38 91.1 82.6 Gel+Dye 0.02 62 ⁇ 5 37 93.3 84.8 0.04 50 ⁇ 5 39 93.2 84.6 0.08 58 ⁇ 5 40 93.9 85.4 0.10 56 ⁇ 5 39
• the tanks of the processor were filled with the solutions described in Example 1.
• Replenishers were made up as described below and the rate of replenishment of the bleach and fix adjusted so that the bleaching and fixing were just adequate to remove the silver from the film after three tank turnovers of seasoning.
• Developer Replenisher Diethylenetriaminepentacetic acid 2.0g Sodium sulphite anh.
• the resulting replenishment rates (expressed as mls per linear metre of film) can be reduced by having a dye AHU layer. This would result in a saving of over 75% iron and associated chelate in the effluent and 4% sulphur compound from the fixer.
• Example 2 was repeated but in this instance the replenishment rates of the bleach and fixer were held at 21.9 mls/m and 28.9 mls/m respectively and the concentrations of the active ingredients in the replenishers varied until the process just remove all the silver from the films after seasoning for three tank turnovers. The results are shown in the table below.
• Antihalation layer Replenisher concentrations Bleach Fixer Silver AHU 0.15 molar 146g/l Dye AHU 0.14 molar 140g/l
• the fixing time for the film with the silver AHU was 190s and that with the dye AHU 170s. This shows a benefit in fixing time of a dye AHU layer in an all sodium fixer.

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

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Citations (2)

• 1993
  • 1993-02-25 EP EP93200538A patent/EP0559276A1/en not_active Withdrawn
  • 1993-02-26 JP JP3832693A patent/JPH063789A/ja active Pending

Patent Citations (2)

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