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

• photographic silver halide emulsions for producing black-and-white images can be reversal processed by subjecting the exposed emulsions to conventional development, followed by bleaching, clearing, and reversal re-exposure, followed by a subsequent development step.
• the exposed emulsions can be subjected to conventional black-and-white development, followed by reversal exposure and subsequent color development. Both of these processes require that the exposed silver halide emulsions, after a first development, be given a subsequent reversal exposure before any further development can take place to produce the desired positive image.
• the reversal re-exposure for the processing of black-and-white or color reproductions can be eliminated by treating the photographic silver halide emulsions after a first (negative) development with a solution containing an alkali metal (e.g., sodium, potassium, etc.) borohydride.
• an alkali metal e.g., sodium, potassium, etc.
• the emulsions are exposed in the customary manner and given a first development in an ordinary photographic silver halide developer.
• the developed films are then Washed and given a bleaching treatment in an ordinary photographic bleach bath containing an oxidizing agent, such as permanganate, dichromate, etc.
• an oxidizing agent such as permanganate, dichromate, etc.
• the film is again washed andtreated in a clearing bath, after which the film is again rinsed.
• Treatment of the film with an alkali metal borohydride aqueous solution produces a positive image, free from stain, without any exposure to light.
• the concentration of the alkali metal borohydride solution can be controlled so that no image is produced directly.
• the treated emulsion can be given a conventional development which rapidly produces the desired positive image.
• concentration of the alkali metal borohydride in the treating solution can vary depending upon whether it is desired to produce an image directly without any subsequent development, or Whether it is desired to use a second development in a conventional photographic developer. In general, the concentration of the alkali metal borohydride can vary from about 0.1 g./liter to concentrations as high as 30 g./.liter. While more concentrated solutions 2,984,567 Patented May 16, .1961
• the alkali metal borohydride treatment should not be used until immediately prior to the last color development step, inasmuch as the alkali metal borohydride will nucleate all silver halide which has not been exposed arid developed previously.
• the alkali metal borohydride treatment it is possible to use the alkali metal borohydride treatment immediately prior to the last color development step and to thus eliminate the re-exposure preceding that step.
• Particularly useful color films for reversal processing according to the method of our invention are films comprising a conventional support, such as cellulose esters, glass, polyester film, polyvinyl acetal film, polycarbonate film, etc., having coated thereon at least two silver halide layers which have been sensitized to particular regions of the spectrum.
• a conventional support such as cellulose esters, glass, polyester film, polyvinyl acetal film, polycarbonate film, etc.
• These emulsions have incorporated therein the color-forming components or couplers, which combine with the oxidation products of the photographic color developers, to produce the desired color images.
• a coupler for the cyan image e.g., a phenolic coupler
• a green-sensitized photographic silver halide emulsion having incorporated therein a coupler for the magenta image e.g., pyrazolone coupler
• the photographic element can also contain conventional interlayers and filter layers, such as a yellow filter layer beneath the blue-sensitized emulsion to prevent exposure by blue light to either the redor green-sensitized emulsion.
• Photographic color films of the above-described type can be processed by a technique requiring fewer steps than the processing of color films of the Kodachrome type mentioned above.
• Example 1 An ordinary photographic silver halide emulsion, such as Kodak PlusX 16 mm. Reversal Film was exposed to a step wedge in an Eastman Type Ib sensitometer and then developed for 3 minutes in a developer having the following composition:
• Example 2 A photographic multi-layer color element containing three differentially sensitized photographic silver halide emulsion layers, having color-forming agents or couplers incorporated therein, was exposed in the usual manner to a subject. The exposed color film was then developed in a developer having the following composition:
• the element was again washed and treated once again with the clearing and fixing bath identified above.
• the element was again washed and treated in a stabilizing bath having the following composition:
• Formaldehyde (37% by weight) cc 7.0 Dispersing agent 1 g 0.5 Water to make 1 liter.
• Triton-X 100 i.e., an alkylaryl polyether alcohol (octylphenoxy poiyethoxy ethanol).
• Photographic color elements which can be processed according to the method described in Example 2 above include the elements shown in Schinzcl U.S. Patent 2,266,443, issued December 16, 1941, and Fierke U.S. Patent 2,272,191, issued February 10, 1942, for example.
• Photographic elements, wherein the silver halide emulsions contain the coupler or color-forming component in dispersed form, have been found particularly suitable for the process described in Example 2. It has been found that ordinary processing of such reversal-type films frequently causes a re-reversal effect, particularly in the magneta dye image and a density loss in the shoulder region of the reversal exposure scale.
• Example 3 A photographic silver chlorobromide emulsion was exposed to a step wedge in the usual manner and then developed for about 2 minutes in a developer for high contrast emulsions, such as a developer having the following composition:
• Development of the exposed photographic silver halide emulsions to produce a black-and-white negative image as described in the foregoing examples can be accomplished using any of the conventional developers customarily employed in photographic art for producing black-and-white negative images.
• Such developers include compounds known as polyhydroxybenzenes (e.g., hydroquinone, catechol, pyrogallol, etc.) and N-substituted aminophenols (e.g., N-methylaminophenols, N- ethylaminophenols, etc.), or mixtures of such developers.
• Prominent among such developing agents for the rapid development of photographic images are those comprising hydroquinone and Elon developer (N-methylpaminophenol).
• Color development can be carried out using any of the well known color-forming developers which are capable of coupling with the color-forming components or couplers.
• Particularly useful color-forming developers are the phenylenediamines and substituted derivatives thereof.
• Typical of such color-forming developers are the sulfonamidosubstituted p-phenylenediamines disclosed in Weissberger U.S. Patent 2,548,574, issued April 10, 1951, the substituted p-phenylenediamines disclosed in Weissberger et al. U.S. Patents 2,552,240-2, issued May 8, 1951, and the substituted p-phenylenediamines disclosed in Weissberger et al. U.S. Patent 2,566,271, issued August 28, 1951.
• Other phenylenediamine color-forming developers can be employed to like advantage in the process of our invention.
• the extent of treatment will obviously depend upon the type of film being treated and whether one de sires to obtain merely a black-and-white image, or whether one desires to process a color film to produce subtractively-colored images.
• the pH of the alkali metal borohydride solutions can be varied to modify the activity of the alkali metal borohydrides. In general, we have found that the pH should advantageously not be allowed to drop below about 10, since these borohydrides become somewhat unstable at too low pH (i.e., toward acid side of neutrality) values.
• the method of processing color films as herein described is particularly useful where the photographic silver halide emulsions are hardened prior to the treatment with the alkali metal borohydride solutions.
• the photographic silver halide emulsions are hardened prior to the treatment with the alkali metal borohydride solutions.
• hydrazine compounds such as phenylhydrazine, l-naphthylhydrazine, p-bromophenylhydrazine, etc.
• phenylhydrazine, l-naphthylhydrazine, p-bromophenylhydrazine, etc. can be used, though less advantageously than the alkali metal borohydrides of our invention.
• Other hydrazine compounds which can be used comprise those shown in Ives U.S. Patent 2,588,982, issued March 11, 1952. Again, the alkali metal borohydrides of our invention have distinct advantages over the hydrazine compounds shown in the United States patent.
• a photographic reversal process comprising eX- posing a photographic silver halide emulsion to an im-' age, developing said photographic silver halide emulsion to produce a black-and-white negative image by contacting said exposed photographic silver halide emulsion with a photographic developer, and subsequently obtaining a reversal positive image by contacting said photographic silver halide emulsion with a nucleating agent for a sufficient time only to nucleate previously unexposed silver halide substantially without the formation of a visible image, followed by contacting said photographic silver halide emulsion with a second photographic developer for a suflicient time to develop a visible image, the step of nucleating said photographic silver halide emulsion by contacting said photographic silver halide emulsion with an aqueous solution of an alkali metal borohydride having a pH of at least 10.0 and containing at least 0.1 g./liter of solution but not more than 30 g./
• a method of producing a photographic color reproduction comprising exposing to a colored image a photographic element containing at least two photographic silver halide emulsion layers which have been differentially sensitized to diiferent spectral regions, developing said photographic element to a negative blackand-white image by treatment with a photographic blackand-white developer, contacting said photographic element with a nucleating agent for sufiicient time only to nucleate previously unexposed silver halide substantially without the formation of a visible image, and developing said photographic element in a photographic color developer in the presence of a color-forming compound which couples with the oxidation products of said photographic color developer to produce a colored image, the step comprising nucleating said previously unexposed silver halide by contacting said photographic element with an aqueous solution of an alkali metal borohydride having a pH of at least 10.0 and containing at least 0.1 g./liter of solution but not more than 30 g./liter of solution ot an alkali metal borohydride selected from the
• a method of reproducing a photographic color reproduction comprising exposing to a colored image a photographic element comprising a support having coated thereon three photographic silver halide emulsion layers, one of said layers being sensitive to the red region of the spectrum and having dispersed therein a coupler for producing a cyan image, one of said layers being sensitive to the green region of the spectrum and containing a coupler for producing a magenta image, and the third one of said layers being sensitive to the blue region of the spectrum and containing a coupler for producing a 7 yellow image, developing said photographic element in a photographic black-and-white developer to produce a negative image, contacting said photographic element with a nucleating agent for a sufiicient time only to nucleate previously unexposed silver halide substantially without the formation of a visible image, developing said photographic element in a photographic phenylenediamine color developer to produce colored images bearing a complementary relationship to the color in the original being produced, contacting said photographic element with a photographic clearing and fixing solution, contacting of

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

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Cited By (5)

Citations (8)

• 0
  • BE BE573379D patent/BE573379A/xx unknown
• 1957
  • 1957-11-29 US US699478A patent/US2984567A/en not_active Expired - Lifetime
• 1958
  • 1958-11-28 FR FR780406A patent/FR1221623A/fr not_active Expired
  • 1958-12-01 GB GB38748/58A patent/GB904462A/en not_active Expired

Patent Citations (8)

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