Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B39/00—Other azo dyes prepared by diazotising and coupling
• • 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

Definitions

• the present invention provides an improvement in a process for producing color photographs by the silver dye bleach method.
• the improvement comprises treating photographic layers containing gelatine, a metallizable azo dyestuff fast to dilfusion, being freed from metallic silver by oxidation, with a water soluble compound of a metal having an atomic number of at least 24 and at most 29.
• the photographs have an improved fastness to light which also is manifested by pure colors free from stain.
• the present invention provides an improvement in a process for producing color photographs by the silver dye bleach method.
• their poor fastness to light is a disadvantage of the known color photographs. This is particularly true of materials processed by the dyeforming development. It is, however, also true of the socalled silver bleaching out process in which the dyestuffs contained in the individual layers are bleached out depending on the quantity of silver produced photographically in the layer.
• the unsatisfactory fastness to light of pictures produced by the silver dye bleaching method is attributable to various reasons. It can be substantially improved in the present process for making color photographs by the silver dye bleach method wherein a color image containing material, having at least one gelatine layer containing a metallizable azo dye and being resistant to diffusion, is freed from metallic silver by oxidation.
• the improvement comprises treating said material subsequent to said oxidation with a water soluble compound of a metal having an atomic number of at least 24 and at most 29 in an aqueous medium of pH 3.5 to 11.5.
• the heavy-metal atom may be present, for example, in the anion of a complex derived from an organic, colorless hydroxycarboxylic acid.
• a complex derived from an organic, colorless hydroxycarboxylic acid As relevant examples may be mentioned the complexes consisting of an alkali metal salt or ammonium salt with a heavy metal salt of citric acid, lactic acid, tartaric acid or of a monocyclic orthohydroxycarboxylic acid of the benzene series such as 4- or 6-methyl-1-hydroxybenzene-2-carboxylic acid or preferably of salicylic acid not containing any further substituents.
• heavy metal amine complex compounds derived from ammonia or a lower aliphatic amine such as methylamine, ethylamine, mono-, dior triethanolamine, or from a pyridine base such as pyridine itself or from a picoline or from an amino-carboxylic acid such as a glycine.
• a complex compound obtained in known manner for the treatment of the photographic material in water or in another suitable solvent it may in some cases be prepared immediately before use or made up into a stock solution, for example by adding to an aqueous solution of copper sulfate tartaric acid and then sodium hydroxide solution until a weakly alkaline reaction is achieved, or by treating the copper sulfate solution with excess aqueous ammonia.
• the present process may be performed with for example, a monoazo, disazo or polyazo dyestufi which may be free from, or preferably may contain, groups imparting solubility in water, more especially sulfonic acid groups.
• the tint depends On the individual purpose so that dyestuffs to be used prefentially are those of yellow, cyan, and magenta tint of extreme purity.
• the stability of the metal-dyestuff complexes in an aqueous medium at an elevated temperature is of minor importance so that there is no objection to using in the present case dyestuffs containing groups capable of forming metal complexes that are far too unstable for use in dyeing textile materials and accordingly produce complexes that are not fast to washmg.
• the complex-forming azo dyestuff may contain an atomic grouping of the formula
• the azo dyestufis mentioned above there may be used with advantage also those which contain at least one azo linkage carrying a substituent in vicinal position to the other nitrogen atom, said substituent being capable of forming together with the hydroxyl group a complex heavy-metal compound.
• complex-forming groups of this composition may be mentioned ortho-hydroxy-ortho'-alkoxy groups, more especially the ortho-hydroxy-ortho'-methoxyazo group, the ortho-hydroxy-ortho-aminoazo group, the ortho-hydroxyortho-carboxymethoxy-azo group, the ortho-hydroxyortho'-carboxyazo grouping and the ortho:ortho'-dihydroxyazo grouping.
• dyestuffs in the case of which the complex may be formed, instead of at the substituents in vicinal positions to an azo linkage, for example, at an 8-hydroxyquinoline radical or more especially at a salicylic acid grouping. It will be readily understood that the dyestuifs may contain two or more identical or difierent groups capable of forming complexes.
• the treatment with the heavy-metal compound is performed at a pH value of at least 3.5, advantageously of at least 4 and of at most 11.5.
• a pH value of at least 3.5 advantageously of at least 4 and of at most 11.5.
• heavy-metal-dyestuif complexes are still stable, while in a more strongly acidic medium they decompose extensively or even completely, or are at best only formed in a minor amount. For this reason it is of advantage to per-form the treatment with the heavy-metal compound after an optional treatment in a strongly acidic medium.
• the present invention offers considerable advantages over the known processes. While very many dyestuffs that are fast to light are known, only some of them are suitable for use in the silver dye bleach process because they must satisfy numerous requirements arising from other aspects of the photographic process. Thus, for example, the dyestuffs to be used in the silver dye bleach process must be compatible with the individual constituents of the silver halide emulsion; they must satisfy certain spectral conditions, and they must lend themselves to bleaching out. Many dyestuffs that are fast to light are unsuitable because they have a strong desensitizing effect on the silver halide emulsion.
• the fastness to light depends very much on the substratum so that, for example, certain dyestuffs that are fast to light when applied to cotton are much less fast to light in gelatine.
• the different additives required to be present in a gelatine emulsion or in a layer adjacent thereto such, for example as organic bases, which act as sensitizers or have the purpose of counteracting the tendency of the dyestuffs to diffuse, have a disadvantageous effect on the fastness to light of the dyestuffs in the finished image.
• After-treatment according to the present process not only enhances the fastness to light of the dyestuif as such, but it may also effect a chemical change in the substratum and in the additives so that they lose their harmful influence.
• the advantages in this connection are more especially that the fastness to light does not materialize until after the after-treatment, while during the manufacture of the photosensitive material and during its development the light fastness of the dyestuif need not be considered; as a matter of fact it is even possible to use measures that jeopardize the fastness to light, but that can be annulled or eliminated by the after-treatment.
• dyestuffs that are at first free from heavy metal and thus have less fastness to light but which have better compatibility with the emulsion; by virtue of their constitution do not diffuse or can be made resistant to diffusion; lend themselves well to bleaching and are thus capable of satisfying the requirements involved in the treatment process.
• the after-treatment with a heavy-metal compound converts the dyestuifs at the end of the treatment into a form of considerably better fastness to light.
• the azo dyestuffs are reduced to ortho-hydroxyaminoaryl or orthodiaminoaryl compounds, and it is generally known that such ortho-disubstituted compounds are easily oxidizable.
• the largest possible quantity of the reduction product is obtained where the dyestuffs are completely bleached out and where the white parts of the image should be.
• the ortho-hydroxyaminoand diamino compounds easily form colored oxidation compounds. It was to be expected that the treatment with metallizing agents would stain the color images and particularly in the parts which should be white. It is just here that the largest quantity of undesirable reduction products is to be found, and just here, too, that the colored oxidation products are the least tolerable. However, quite surpris ingly, no such staining takes place in the present process.
• Example 1 A film is coated with a gelatine layer containing per square meter 2.5 grams of silver as silver bromide, 0.6 gram of the yellow dyestuff of the formula:
• the film is exposed in contact with a stepped spectroscope wedge, developed in a metol-hydroquinone developer and fixed.
• the film is then treated in a dye bleaching bath containing per liter Hydrochloric acid of 36% strength cc Potassium bromide grams 100 Thiourea do 50 2:3-diaminophenazine milligrams 2 whereby the dyestuif is destroyed in the areas where metillie silver is present.
• the excess silver is oxidized in a bath containing per liter Copper sulfate grams 100 Sodium chloride do 100 Hydrochloric acid of 36% strength ..cc 100 and eliminated in a fixing bath. Between all baths and at the end the film is thoroughly rinsed.
• Example 2 A yellow color image obtained in this manner is aftertreated for 3 minutes in a solution consisting of Nickel sulfate grams 1.0 Monoethanolamine do 2.0 Water cc 100
• Example 2 A film is cast which contains, instead of the dyestufi used in Example 1, the yellow dyestuif prepared by coupling on both sides tetrazotized benzidine-2:2'-disulfonic acid with 1-phenyl-3-methyl-5-pyrazolone. The film is de- G O-NH OH CH;
• Example 3 The dyestuff of Example 1 is replaced by the magenta NEOaS NaOaS dyestufi obtained by coupling diazotized 1-amino-2-ethoxy- 70 benzene with 1-(para-acetylaminobenzoylamino)-8-hydroxy-naphthalene-3:6-disulfonic acid.
• the procedure of Example 1 is followed. After-treatment with the nickel bath of Example 1 or with the cobalt ably.
• one of the following baths can be used with equal success:
• Example 1 After-treatment in one of the aforementioned baths, for example in bath (B) of Example 3, improves the fastness to light substantially.
• I S OaNa (obtained by coupling tetrazotized 3:3'-dihydroxy-4:4- diaminodiphenyl with l-amino-8-hydroxynaphthalene-2: 4-disulfonic acid in the presence of calcium hydroxide and pyridine) is dissolved in gelatine and rendered fast to diffusion, for example with anhydro-biguanido benzyl albath of Example 2 improves the fastness to light consider- 75 cOhOl acetate.
• this dyestuff is used in the usual manner in the silver dye bleach process it produces a blue What is claimed is: component image which becomes fast to light on after- 1.
• a similar imwith water-soluble compound of metal having an atomic provement in the fastness to light is also achieved by using number of at least 24 and at most 29 in aqueous medium instead of the copper acetate solution a solution that conf H 3, 5 to 11,5, tfiins to grams of Potassium titanium Sulfate P 10 2.
• a color image-containing ma- Example 6 terial having at least one gelatine layer containing metalhe dyestufi specified in Example 5 may be replaced lizable azo dye with at least one salicylic acid group and by the dyestufl of the formula: being resistant to dillusion, is freed from metallic silver O-GHz-COOH
• the improvement comprising treating said mium acetate, cobalt acetate or nickel acetate, a greenish material subsequent to said oxidation with water-soluble blue image is obtained which is fast to light.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
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• Silver Salt Photography Or Processing Solution Therefor (AREA)

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• 0
  • BE BE591759D patent/BE591759A/xx unknown
  • NL NL252552D patent/NL252552A/xx unknown
• 1959
  • 1959-06-12 CH CH7435859A patent/CH381087A/de unknown
• 1960
  • 1960-05-27 GB GB18919/60A patent/GB899758A/en not_active Expired
  • 1960-06-11 DE DEC21658A patent/DE1125279B/de active Pending
  • 1960-06-11 ES ES0258841A patent/ES258841A1/es not_active Expired
• 1965
  • 1965-05-21 US US457838A patent/US3436218A/en not_active Expired - Lifetime

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