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
  • G03C5/38—Fixing; Developing-fixing; Hardening-fixing

Definitions

• the invention relates to a method of processing exposed photographic material, characterized by a final bath which leads to photographic images with improved keeping qualities.
• Conventional photographic processing includes the fixing of the unexposed silver halide, whereby the silver halide is converted to a complex compound with alkali metal or ammonium thiosulfates and, in the subsequent rinsing, is washed out to a greater or lesser extent, depending on the rinsing period and water temperature. Practically complete removal of the silver thiosulfate complex requires rinsing for at least half an hour at about 25 C. Residual thiosulfate is highly disadvantageous, since particularly in a weakly acidic photographic layer the density of the silver image is reduced during storage because of the formation of silver sulfide. Moreover, yellowish or brownish stains are formed in the black silver, particularly under tropical conditions. If the residual thiosulfate is uniformly distributed in the layer and in the support, a uniform decrease in density occurs, and this is particularly noticeable in the brighter image portions by a color change towards yellow.
• the harmful influence of residual thiosulfate can also be suppressed by an alkaline bath, since thiosulfate decomposition occurs more slowly in alkaline media than in acidic.
• the disadvantage of the last two types of baths is that the harmful influence of the thiosulfate is not eliminated, but is only reduced.
• a substantially longer rinsing time is required for pictures on supports having the thickness .of cardboard than for pictures on supports having the thickness of paper.
• An additional disadvantage is that with the continuously running paper web in continuous printing processors, small quantities of thiosulfate are constantly carried along and these are concentrated in the drying cloth of the drying drum. Because of this, the pictures are once again contaminated with thiosulfate, and this can only be overcome by frequently changing the drying cloth.
• Water-soluble, aliphatic monochlorine-substituted or monobromine-substituted compounds which further contain at least one aldehyde, carboxyl or sulfo group and which have up to 5 carbon atoms, are preferred.
• the following are examples of particularly suitable compounds.
• the eflicacy of the compounds used in the manner according to the invention is extremely surprising and is limited to monohalogen compounds.
• the aqueous baths used in the processing step according to the invention advantageously contain 0.1 to g. of the monohalogen compounds per liter of bath. Saturated solutions of the compounds can also optionally be used. The optimum concentration can be determined by a few simple routine tests. It depends on the nature of the photographic material and the required treatment time. In most instances, a concentration of 3 to 30 g. per liter is sufficient.
• the treatment times can also fluctuate within Wide limits but it is generally sufficient to treat the photographic materials with the bath according to the invention for about 2 minutes.
• the destruction of the residual thiosulfate is not completed in the bath, but since the monohalogen compounds of the inventive invention bath remains in the layer, any remaining thiosulfate that did not react in the bath is completely destroyed during the subsequent hot drying and also during storage of the picture, particularly under tropical conditions.
• a conventional photographic black-and-white positive paper which comprises a gelatino-silver chlorobromide emulsion layer on a baryta-coated paper support, is exposed to form an image and is developed in a developer having the following composition:
• Another strip of the fixed material is rinsed for 1 minute and treated for 2 minutes in a bath having the following composition: 30 g. of sodium chloroacetate dissolved in 1 liter of water.
• the high-glaze drying is immediately carried out.
• thiosulfate can no longer be detected or can be detected only in a negligible amount.
• the keeping qualities of the silver image in tropical climatic conditions are excellent.

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

Applications Claiming Priority (1)

Publications (1)

Family

ID=6939820

Family Applications (1)

Country Status (7)

Cited By (2)

• 1968
  • 1968-02-20 US US706767A patent/US3598588A/en not_active Expired - Lifetime
  • 1968-02-21 NL NL6802470A patent/NL6802470A/xx unknown
  • 1968-02-26 CH CH270368A patent/CH500510A/de not_active IP Right Cessation
  • 1968-02-28 BE BE711377D patent/BE711377A/xx unknown
  • 1968-03-08 FR FR1559927D patent/FR1559927A/fr not_active Expired
  • 1968-03-08 GB GB11370/68A patent/GB1160205A/en not_active Expired
  • 1968-03-08 JP JP43014685A patent/JPS5026928B1/ja active Pending

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