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
  • G03C5/38—Fixing; Developing-fixing; Hardening-fixing
  • G03C5/39—Stabilising, i.e. fixing without washing out
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/164—Rapid access processing

Definitions

• This invention relates to photography and more particularly to a method for improving the silver image stability of rapid-processed photographic prints.
• R' representing a hydrogen atom or an alkyl group, such as methyl, carboxymethyl, ethyl, propyl, butyl, etc., especially an alkyl group containing from 1 to 4 carbon atoms
• Y and Z represent hydrogen atoms or monovalent substitutents such as alkyl groups (e.g., methyl, ethyl, etc.) or hydroxyl groups and may be the same or different, or Y and Z together represent the atoms necessary to complete a benzene ring.
• the silver image preserving compounds of our invention can be incorporated in the developing solution, in the stabilizing solution, or in a special treating bath, or the compounds can be incorporated in the lightsensitive silver halide layer directly.
• the compounds of our invention are effective in preventing fading on storage of rapidly-processed photographic prints in a humid, high-temperature environment.
• Representative compounds of the general formula given above which can be used in the present invention are: (1) 2',3' dihydrobenzothiazolo-Z',3',5,4-triazole(1,2,4)-
• a silver halide photographic emulsion preferably a gelatin-silver halide emulsion is exposed in the usual way and developed with a suitable silver halide developing solution.
• a stabilizing solution is to make the undeveloped silver halide substantially incapable of change on further light exposure.
• the stabilizing agent must be a compound which does not react with metallic silver and which forms a light-stable, silver complex by reacting with the undeveloped silver halide in the emulsion layer.
• Stabilizing agents suitable for this purpose are compounds containing double-bonded sulfur or an SH linkage, such as alkali metal and ammonium thiocyanates, alkali metal and ammonium thiosulfates,
• the present invention is primarily directed to improvements and further silver image preservation in thiocyanate rapidly-processed prints.
• a thiocyanate stabilizing compound such as ammonium thiocyanate, or an alkali metal thiocyanate
• concentration of the organic thiol compound can vary over a wide range. When the imagepreserving organic thiol compound is used in the developer solution, the preferred range of concentration is from about 0.05 gram to about 3.0 grams per liter of developer solution.
• the photographic emulsions used in the practice of this invention are generally of the developing-out type. Suit able emulsions for use in this invention have been described in Kendall and Wood, US. Patent 2,669,515, issued February 16, 1954; Kendall and Hill, US. Patent 2,541,472, issued February 13, 1951; and Brice, US. Patent 2,448,857, issued September 7, 1948.
• the emulsions used in this invention can advantageously be hardened emulsions.
• the emulsions may be hardened with any suitable hardener for gelatin, such as formaldehyde, a halogen-substituted aliphatic acid such as mucobromic acid as described in White, US. Patent 2,080,019, issued May 11, 1937, or by compounds such as those described in US. Patents 2,725,294; 2,725,295; and 2,725,305, issued November 29, 1955.
• the emulsions can be coated on paper or other opaque supports or on any of the well-known transparent supports such as cellulose nitrate, cellulose acetate, polyethylene terephthalate, polystyrene, polycarbonate, etc.
• the developing agents which can be incorporated into the emulsions according to an embodiment of this invention comprise developing agents such as 3,4-dihydroxydiphenyl, 2,3-dihydroxydiphenyl, hydroquinone compounds,
• organic thiol preserving compounds suitable for use in our invention can be prepared according to the methods described in our co-pending application, Williams, US. application Serial No. 655,472, filed April 29, 1957, and in Knott et 211., US. Patent 2,861,076, patented November 18, 1958.
• EXAMPLE 1 The following example illustrates a manner of practice r 4 of our invention.
• a suitable emulsion was prepared as follows:
• Solutions were made of (A) 25 grams of gelatin in 1 liter of water at 40 C., (B) grams of silver nitrate in 500 cc. of water at 20 C., and (C) 35 grams of sodium chloride in 500 cc. of water. Solutions (B) and (C) were simultaneously run into Solution (A) at a uniforrnrate while stirring the latter over a period of about 10 minutes. Solution (B) was not allowed to run in faster than (C). Thereafter 150 grams of gelatin in 1450 cc. of Water at 40 C. were added. The emulsion was hardened using a suitable gelatin hardening agent such as formaldehyde. The emulsion was then coated on a paper support over an area of about 500 square feet.
• a suitable gelatin hardening agent such as formaldehyde
• Samples of the dry product were then exposed in a number of ways to a subject, including contact with or projection of a negative and by reflex exposure with a subject comprising printed matter on a paper base. Thereafter the exposed samples of the element were processed by surface application of the following solutions in a small processing machine.
• the machine was run at 10 feet per minute giving ap proximately 2 seconds treatment in the developer solution followed with about 3 seconds treatment in the stabilizer solution.
• the reflection density of the control print after incubation was 0.95 whereas the print processed according to this invention had a reflection density of 1.4.
• the reflection densities refer to the relative densities of the respective prints as measured on a conventional reflection densitometer.
• Example 2 The tests of Example 1 were repeated except that a direct-positive emulsion, such as that described in Kendall et al., US. Patent 2,541,472, issued February 13, 1951, was used. After exposure the test print was processed in a developer solution of Example 1 which contained the organic-thiol compound, 2',3-dihydrobenzothiazolo-2'3'- 5,4-triazole(1,2,4)-3-thiol. A control print was handled in a similar manner except that the developing solution for development thereof did not contain said organic compound. Both test and control prints were stabilized in the thiocyanate stabilizer of Example 1. After a 7-day 120 F., 75 percent relative humidity (RH) incubation period, the test print showed areflection density of 1.1 whereas the control print had a reflection density of 0.9.
• RH relative humidity
• EXAMPLE 3 A sheet of direct-positive film as used in Example 2 was exposed and processed as in Example 1, except that in this example 0.5 gram per liter of the following com- EXAMPLE 4 A direct-positive emulsion was prepared as in Example 2 except that in this example development was in a developer of Table I except that 0.5 gram per liter of the following compound was added to the developer, namely, 1',2 dihydropyridino-2,l'-5,4-triazole(1,2,4)-3- thiol.
• the print After 7 days moist incubation (100 F., 75 percent RH) the print showed only slight loss of maximum density as measured by reflection density, as in Example 1, when compared to the control print which was developed in a developer solution not containing a preserving thiol compound according to the present invention.
• EXAMPLE 5 The following example illustrates a manner of practice of our invention wherein a developer compound was incorporated into the emulsion directly.
• a suitable silver halide emulsion was prepared as follows:
• Solutions were made of (A) 25 grams of gelatin in 1 liter of water at 40 C., (B) 100 grams of silver nitrate in 500 cc. of water at 20 C., and (C) 35 grams of sodium chloride in 500 cc. of water. Solutions (B) and (C) were simultaneously run into solution (A) at a uniform rate while stirring the latter over a period of about 10 minutes. Solution (B) was not allowed to run in faster than (C). Thereafter, 150 grams of gelatin in 1200 cc. of water at 40 C. were added. 25 grams of 3,4-dihydroxydiphenyl were then dissolved in 250 cc. of methyl alcohol. This solution was slowly added to the above mixture.
• the emulsion was hardened using a formaldehyde gelatin hardening agent.
• the emulsion was then coated on a paper support over an area of about 500 square feet. Samples of the dried product were then exposed by contact with a negative which comprised the subject matter to be printed. Thereafter, the exposed samples of the element were processed by surface application of the following solutions in a small processing machine:
• the machine was run at 10 feet per minute giving approximately 2 seconds treatment in the developer solution followed with about 3 to 4 seconds treatment in the stabilizer-preservation solution of Table IV.
• EXAMPLE 6 A sheet of photographic film prepared as in Example 5 was exposed and processed as in Example 5 except that according to the present example the organic-thiol compound was incorporated into the emulsion directly. In this example, therefore, a stabilizer solution as shown in Table II was used in the stabilization step. The results of the trial showed similar improved silver image preservation in the rapid-processed photographic prints of this example.
• the stabilization bath acid to counteract alkali present in the developing solution.
• the alkali of the developing solution is not especially critical since carbonate, caustic alkali and borates all give useful results, although, as is apparent, strong alkali is preferred in those cases where theemulsions incorporate a developing solution since a strong alkaline treating solution will increase the speedof development of the emulsion layers containing the somewhat weaker developing agents, such .as the dihydroxydiphenyl compounds.
• a. precaution should be taken to use well-hardened emulsions so as to prevent the emulsion from adhering to the surface of the applicator such as a pad. In case the emulsion has not been hardened sufficiently prior to processing, this can be done with a formaldehyde hardening bath before or after the development step or in any other suitable way.
• the emulsion be immersed in the developer and stabilizing solutions, or as in the case of the developer incorporated emulsions, the alkaline and stabilizing solutions. It may be preferred, however, merely to moisten the surface of the exposed emulsion with the required solutions. In those cases where paper supports are used, the support may become wet on immersion such that the drying time is greatly ex tended.
• a rapid process for producing a stable visible image in a photographic silver halide emulsion layer containing a latent image consisting in (A) processing said silver halide emulsion layer by developing said layer in a photographic silver halide developing solution and thereafter stabilizing said silver halide emulsion layer by applying an aqueous solution containing at least one stabilizing compound selected from the group consisting of alkali metal thiocyanates, alkali metal thiosulfates, ammonium thiocyanate, and ammonium thiosulfate to form a lightinert complex with resulting undeveloped silver halide, said complex being left in the emulsion layer, said emulsion layer being imbibed during said processing with an aqueous solution containing at least 0.05 gram of a thiol compound having the general formula:

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

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