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
  • G03C5/50—Reversal development; Contact processes

Definitions

• This invention relates to an improved reversal process for use in the production of positive photographic images.
• the photographic material is exposed to produce an image and is then developed in a first developer which is a conventional black-and-white developer. It is then exposed uniformly and this exposed material is subjected to a second development with a blackand-white developer or colour developer. The processing is completed by fixing or bleach fixing the photographic material.
• Suitable compounds include those of the following formula:
• Suitable compounds are, for example, alkali metal or alkaline-earth metal boranocarbonates, especially sodium or potassium boranocarbonate.
• the compounds to be used according to the invention can be prepared by the process described in the Journal Inorganic Chemistry, vol. 6 (1967), pp. 817-822.
• the process according to the invention may be used in the production both of photographic black-and-white reversal images and photographic colour reversal images. Owing to the great practical importance of the last mentioned reversal process, the process according to the invention is preferably used in the production of colour reversal images.
• the photographic materials to be worked up may have the usual compositions.
• the materials used in the production of colour reversal images are multi-layer films on transparent support layers made, for example, of cellulose esters, polyesters or polycarbonates or multi-layer materials on paper supports.
• the usual colour reversal materials contain a blue sensitive silver halide emulsion layer with a colour coupler for the production of the yellow partial image, a green sensitive silver halide emulsion layer with a coupler for the production of the magenta partial image and a red sensitive silver halide emulsion layer with a colour coupler for the production of the cyan partial image.
• the process according to the invention is, of course, independent of the format of the colour photographic emulsion which is to be worked up. It can be used equally successfully for miniature films, narrow gauge colour photographic films or colour photographic paper.
• the process according to the invention can be used successfully in the production of coloured photographic images by the so-called silver dye bleaching process in r which layers which already contain the dye for the particular partial image are used in known manner.
• the dyes generally azo dyes, are then bleached in the dye bleaching bath in the areas corresponding to the silver image produced during development.
• the boranocarbonates to be used according to the invention can be introduced into the process in a bath containing an aqueous solution thereof preceding the second development; they may also be added to the second developer.
• these compounds can be used especially advantageously in the second developer without any harmful effects.
• the concentration of the boranocarbonates in the treatment baths may vary within wide limits. The optimum concentration can easily be found by a few simple tests and can be adapted according to the special requirements of the photographic material or of the reversal process. Quantities of between 0.05 and 5 g./l. of treatment bath have generally proved to be suiiicient. Concentrations of between 0.1 and 3 g. especially between 0.8 and 2.5 g. are preferred.
• the advantages of the process according to the invention lie in the excellent stability of the treatment baths which contain the chemical fogging agents.
• the intensity of the boranocarbonates as fogging agents is also of special importance since it lies in a particularly advantageous region so that complete development of the reverse materials obtained in accordance with the invention is possible without the photographic properties of the colour reversal materials being impaired in any way by excessive activity. Any dyes present, for example, are not attacked by the boranocarbonates.
• One special advantage which has hitherto not been observed with the use of chemical fogging agents is the improvement of the graininess which can in many cases be observed to be produced when employing the method according to the invention.
• EXAMPLE 1 A colour photographic multi-layered material having a red sensitive, a green sensitive and a blue sensitive silver halide emulsion layer containing colour couplers for the particular patrial images in the light sensitive layers is exposed in a sensitometer behind a grey step wedge in the usual manner.
• the exposed colour film is then developed in a blackand-white first developer solution of the following composition for 18 minutes at a temperature of 20 C.
• the film is then imersed for 4 minutes at a temperature of 19 C. in a stop bath consisting of a 3 sodium acetate solution which has been adjusted to pH 5.2 by the addition of acetic acid.
• Potassium boranocarbonate g 1.0 Sodium hexametaphosphate g 2.0 Sodium sulphite g 5.0 N,N-diethylparaphenylenediamine sulphate g 5.0 Hydroxylamine sulphate g 1.2 Potassium carbonate g 75.0 50% ethylene diamine ml 16 Water up to 1 litre.
• the colour developer is produced by first dissolving all the ingredients other than the potassium boranocarbonate, in 800 ml. of water. An aqueous solution of the fogging agent is then added and the solution is made up to 1000 ml. with water.
• the film is again washed for about 20 minutes and is then treated with the following bleaching bath.
• the pH of the bleaching bath is adjusted to 5.2 with acetic acid.
• the film is then again washed for about minutes and fixed for the same length of time in the following fixing bath.
• the processed material is immersed in a 0.2% aqueous solution of 2 ml. of tetrapropylene benzene sulphonate (pH not below 6.5) and then dried.
• the sensitometric comparison of the resulting positive step wedges shows that the procedure according to the invention is completely equivalent as regard gradation and sensitivity to the convensional method which includes a reversal re-exposure.
• the step wedge obtained by the procedure according to the invention has a considerably finer colour grain.
• EXAMPLE 2 A colour photographic reversal material on a layer support of paper is exposed in a sensitometer behind a step wedge.
• the material After immersion in a stop bath followed by washing, the material is treated with the following colour developer solution for 8 minutes at 20 C. without exposure.
• a light sensitive photographic multi-layer material which is suitable for use in the negative-positive process in the silver dye bleaching process, which contains diffusion-resistant azo dyes in the individual layers and which consists of a red sensitive silver bromide emulsion layer which is situated on the support layer and contains a cyan azo dye, a green sensitive silver bromide layer which contains a magenta dye, a yellow filter layer and an uppermost, blue sensitive silver bromide layer which contains a yellow dye, is exposed under an original to be copied and is then processed at 20 C. as follows:
• Potassium boranocarbonate has no effect on the dyes used. Image-wise reduction of the azo dyes in the second developer as is found, for example, with the known fogging agent, tin chloride, was not observed when using potassium boranocarbonate.

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

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (5)

Cited By (1)

• 1968
  • 1968-02-14 DE DE19681622258 patent/DE1622258A1/de active Pending
• 1969
  • 1969-01-24 GB GB4065/69A patent/GB1195526A/en not_active Expired
  • 1969-01-27 US US794397*A patent/US3563746A/en not_active Expired - Lifetime
  • 1969-02-14 FR FR6903640A patent/FR2001902A1/fr not_active Withdrawn
  • 1969-02-14 BE BE728385D patent/BE728385A/xx unknown

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