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
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/28—Silver dye bleach processes; Materials therefor; Preparing or processing such materials
  • G03C7/29—Azo dyes therefor

Definitions

• a photo- 1 graphic silver halide emulsion layer usually a gelatino silver halide emulsion layer, includes as a uniform dispersion therein, a suitable dyestuff.
• the layer is exposed to light or otherwise rendered developable so that a latent silver image is formed therein.
• This image is developed 20 to a silver image.
• the layer is then treated with a bleach bath which has the efiect of oxidising the silver image and simultaneously reducing (or bleaching) 'the dyestufi in the region of the silver image.
• the silver salts and any residual silver are then removed from the layer 2 and the layerthen contains only a dyestuff image which is complementary in sign to the original silver image.
• dyestufis proposed are unsatisfactory in one or more respects.
• a principal difliculty is to ensure that the dyestufi employed will not diffuse from the gelatin emulsion layer in which it is incorporated, and various proposals, such as mordanting, have been made to overcome this difficulty.
• dyestulfs for use, moreover, it is desirable that they should be bleached rapidly by the bleaching baths employed and also preferable that their inclusion in the emulsion layer should not too seriously reduce the sensitivity of the emulsion.
• the dye should approach as closely as possible to the theoretical requirement that, of red, blue and green light it should absorb all of one while fully transmitting or reflecting both of the others.
• a process for the production of a yellow dyestufi image in a photographic layer comprises including in a light-sensitive gelatino silver halide emulsion layer, or in a plain gelatin layer coated adjacent thereto, a yellow dyestuif of the formula:
• the layer may be dyed with the dyestulf after the exposure step or after the development of the silver image.
• the dyestutf may be included in a plain gelatin layer coated adjacent to the emulsion layer.
• a multilayer material which contains three light-sensitive silver halide emulsion layers, one sensitive to blue light only and the others sensitized to sensitive to blue light only and the other sensitised to layers from recording blue light in addition to the light to which they are sensitised, it is usual to provide a blueabsorbing filter layer between these latter layers and the emulsion which is sensitive only to blue, a common form of assembly being:
• the final product carries positive yellow, magenta and cyan images complementary to the negative silver images formed on development, so that when viewed it SOaH where X is an unsaturated aliphatic, aromatic or hetero- .cyclic divalent radicle, or of the said formula in which subjecting the developed image to treatment which bleaches or removes the silver image and simultaneously bleaches the dyestuff in situ therewith, and removing any residual silver and silver salts from the product.
• the group X may be, for example,
• Suitable non-ionogenic substituents are alkyl, e.g. methyl or ethyl, alkoxy, e.g. methoxy or ethoxy, acylamino, e.g. acetylamino groups or halogen atoms, particularly chlorine.
• the precise hue of the dyestufi varies with the sub stituents present and their position.
• alkyl or alkoxy groups on the intralinear benzene rings in 'meta positionto the azo linkages tend to yield dyes, of more lemon a shade, while the same groups in ortho position to the azo linkages tend to yield dyes of more orange a shade.
• Halogen atoms in these intralinear benzene groups tend to produce more lemon shades.
• Y-CO-X--CO-Y where Y is hydroxyl or halogen, or the two Y groups together represent an oxygen atom, the compound then being an anhydride.
• a process of colour photography comprises a process as just set forth in which the gelatino silver halide layer is blue-sensitive and constitutes one of the layers of a multilayer photographic material which further contains photographic emulsion layers sensitive to green and red light respectively dyed with magenta and cyan dyestuffs, and the said yellow dyestutf is included in said blue-sensitive layer or in a plain gelatin layer coated adjacent thereto. More particularly the invention provides a process in which the said yellow dyed layer is layer (e) of an assembly consisting of:
• the invention further includes such light-sensitive materials employed in the aforesaid processes, and suitable for variants of those processes, which consist of or include a gelatino silver halide emulsion layer containing a yellow dyestufl. as above set forth.
• ZGH G-G-SHIDhODIG acid aminobenzene. l-ammo-et-chlorobenzene-5- l-amino-3-acetylaminoben- .do do yellow yellow-brown. 1 sulphoric glcidb 2 zone.
• C 3 s CH3 CH which is obtained is precipitated by the addition of sodium chloride, filtered off and washed with diluted sodium chloride solution.
• the dried dyestuff is a yellow powder neous addition dropwise of caustic soda lye.
• the disazo dyestuff formed is precipitated by the addition of sodium chloride, filtered off and washed with diluted sodium chloride solution. After drying, it is a yellow-brown powder which dissolves in water with a yellow colour and dyes gelatin in lemon-yellow shades.
• the new dye which dissolves in water with a yellow colour and has a very good aflinity to gelatin.
• the 33.2 parts of the aminodichloride are replaced by the corresponding number of monoazo dyestufi are replaced by a corresponding numparts of maleic acid dichloride, methyl fumaric acid di- P 9 the E dyesmlfs glven "H116 chloride, methyl maleic acid dichloride, bromofumaric following table, or if the acylatmg agent is replaced by hl M f m a corresponding number of parts of one of the acid c onde butadl-ene" l.4-dicarboxylic acid dichloride, or if the 305 parts of the halides given in the following table, then dyestuffs are obtained which have similar properties.
• fumaric acid dichloride is used as acylating agent in each case.
• the dried coating is exposed to light to record an image dyestufi obtained by coupling diazotised l-amino-4- therein and processed at 68 F. as follows:
• ethoxybenzene-Z-sulphonic acid with l-amino-Z-methoxy- S-methylbenzene are dissolved with a neutral reaction in 500 parts of water with the addition of sodium hydroxide.
• 11.3 parts of benzene-1.4-dicarboxylic acid dichloride dissolved in 200 com. of acetone are added dropwise through one dropping funnel and simultaneously an aqueous solution of sodium hydroxide is added through another dropping funnel, both additions being made at 2025 within 1 hour in such a way that the reaction mixture has always a neutral reaction.
• the disazo dyestuff formed is precipitated by the addition of sodium chloride, filtered 01f, washed with diluted sodium chloride solution and dried.
• the new dyestuff corresponds to the formulas OCH;
• Steps 4 and 5 may be omitted if the original emulsion is hardened or provided with a hardened gelatin supercoat.
• dyestufi? in the dyed layer migrates to the undyed layer 2.
• SOQH SO H good resistance to migration, bleach rapidly and etfecwhere X is selected from the class consisting of divalent tively, and are generally of exceptional value in the silverethylenlcally ullsablllated p fadlcles, Phenylene dy b1 h process f colour photography Those dyes radicles and unsaturated divalent heterocyclic radicles,
• X is selected from the class consisting of divalent taining the yellow dyestutf of the formula:

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  • US US2899305D patent/US2899305A/en not_active Expired - Lifetime
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