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
• • 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

Definitions

• the production of a colored photographic image by the silver dyestuif bleaching method is based on the discovery that an azo dyestuff, one of the wide range of azodyestuffs with which the layer-forming substance, especial- 1y gelatine, can be colored, is bleached out depending on the quantity of image-forming silver present in thelayer.
• the silver image is usually produced by exposing the light-sensitive, and in some cases sensitized, silver halide present in the colored layer, and developing and fixing the silver image.
• the method can be applied to a colored layer produced by coloring the layer-forming substance with the azodyestutf before the layer is formed or by coloring the finished layer on its support.
• the method can also be applied to multi-layer photographic materials.
• three colored layers may be applied to a transparent or white pigmented support or to baryta paper.
• a selectively red sensitized silver bromide emulsion colored with a green-blue dyestutf then on this layer there is a selectively green sensitized silver bromide emulsion colored purple, and finally a selectively blue sensitive layer colored yellow.
• an ordinary light source for example, an incandescent tungsten electric lamp or copying color component record with selectively colored light
• the silver bromide is exposed at the appropriate areas of the layers.
• each of the colored layers contains a component color record in the form of a negative silver image in a homogeneously colored layer.
• a suitable dyestutf bleaching bath for example, an acid aqueous solution of potassium bromide and thiourea, and a suitable catalyst, such as aminohydroxy-phenazine, azo-dyestuff present in each layer is bleached out in accordance with the image, so that, in dependence on the quantity of image silver present (and in the simplest case approximately in proportion to the quantity of such silver), the azo dyestuffs are reduced to practically colorless decomposition products according to the following equation:
• R represents the radical of the diazo-compound obtained from the diazo-component R -NH and R represents the radical of the coupling component HR
• R represents the radical of the coupling component HR
• the present invention is based on the discovery of substances which enable the bleaching yield to be decreased, that is to say, the ratio of bleached dyestuff to metallic silver present to be lowered.
• the present invention is concerned with the use of dyestuffs (hereinafter referred to as supplementary dyestuffs) which, like the dyestuffs (hereinafter referred to as image dyestuffs) used for image formation, are
• the present invention provides a process for the production of color photographic images by the silver dyestuff bleaching method, wherein the contrast obtained by bleaching at least one dyestuff serving for image formation is decreased by the presence during the treatment with the dyestuff bleaching bath of at least one dyestuff which is capable of being bleached in the dyestuff bleaching bath in accordance with the image and is capable of being destroyed in a treatment that follows the dyestuff bleaching bath, and which corresponds to the formula in which R represents the radical of a component which is bound to the azo linkage in the l-position of an aromatic or hetero-cyclic ring and contains in the 2- or 4-position of that ring an electron-donating substituent, and Py represents the radical of a 5-pyrazolone bound in the 4-position to the azo linkage.
• dyestuffs of the Formula 1 A number of dyestuffs of the Formula 1 is known, and these dyestuffs can be obtained by methods in themselves known by coupling diazo-compounds of amines of the formula R-NH in which R has the meaning given above, with S-pyrazolones.
• the pyrazolone radicals Py and/or R may, for example, correspond to the formula 1-amino-4-hydroxybenzene, 1-amino-4-hydroxybenzene-3-sulfonic acid, l-amino-4-hydroxynaphthalene, 1-amino-4-methylan1inobenzene, l-amino-4-diethylaminobenzene, 1-amino-2-methyl-4-diethylaminobenzene, 1-amino-2-ethoxy-4-diethylaminobenzene, l-amino-4-(di-fl-hydroxyethyl)-aminober1zene, 1-a-mino-4-dimethylaminobenzene-Z-carboxylic acid, 1-amino-4-dimethylaminonaphthalene, 1-amino-4-benzylaminobenzene, l-amino-4-di-dodecylaminobenzene-Z-sulf
• dyestuffs of the Formula 1 which contain in the radical R in orthoor advantageously para-position to the azo linkage a primary amino group as an electron-donating substituent.
• These dyestuffs can also be made by methods in themselves known, for example, by coupling a S-pyrazolone with a diazo-compound of an aromatic amine which contains in orthoor para-position to the amino group a substituent convertible into an amino group, for example, a nitro or acetylamino group, and subsequently converting the said substituent into a primary amino group.
• a nitro group is reduced or an acetylamino group is hydrolysed.
• the supplementary dyestuff When the supplementary dyestuff is soluble in Water and diffuses, it may be present in the dyestuff bleaching bath or in a bath preceding the dyestuff bleaching bath. However, supplementary dyestuffs which are fast to diffusion or have been rendered fast to diffusion by means of a precipitating agent, are preferred. Such dyestuffs are 4- incorporated in one or more of the emulsions of a multilayer material or in one or more phases of a mixed grain emulsion before the emulsions are cast to make the photographic material.
• the quantity of the supplementary dyestuff varies depending on the degree of flattening of the graduation curve to be brought about.
• the quantity required is generally within the range of 5 to percent calculated on the quantity of image dyestuff.
• image dyestuffs there are used dyestuffs that are decolorizable by metallic silver and are stable in silver bleaching baths, and they are principally azo-dyestuffs.
• image dyestuffs other substances capable of being bleached in accordance with an image such, for example, as diazonium salts or components that yield colored metal complexes, which are converted into dyestuffs after the treatment with the dyestuff bleaching bath.
• image dyestuffs which are fast to diffusion and are incorporated with the material before the casting'operation.
• image dyestuffs may be used which are incorporated by immersion before the treatment with the dyestuff bleaching bath.
• the supplementary dyestuff may also have a flattening effect on the gradation curve of the silver image, whereby it produces a dual flattening effect.
• This additional flattening effect is, probably at least partially, due to the color of the supplementary dyestuff and the optical damping produced thereby.
• the color of the supplementary dyestuff may be similar to the color of the image dyestuff in the same layer or it may be different from the color of the image dyestuff.
• the layers lying above the red-sensitive layer should contain yellow, yellow-red or red supplementary dyestuffs which allow red light to pass through unhindered.
• a typical emulsion layer is produced, for example, by mixing in the appropriate sequence a silver halide (for example silver bromide) emulsion in a colloid (for example gelatine), an image dyestuff fast to diffusion, a supplementary dyestuff fast to diffusion, and the usual additions to emulsions such as optical sensitizers, chemical sensitizers, wetting agents, and then casting the mixture on a support.
• a silver halide for example silver bromide
• a colloid for example gelatine
• an image dyestuff fast to diffusion for example gelatine
• a supplementary dyestuff fast to diffusion for example gelatine
• optical sensitizers for example optical sensitizers, chemical sensitizers, wetting agents
• the composition of the bleaching bath also has an influence on the bleaching ratio of the image dyestuff and the supplementary dye stuff, and therefore on the degree of flattening of the image produced by the supplementary dyestuff. It will therefore be understood that a maximum effect is produced when the composition of the bleaching bath is so chosen that it bleaches the supplementary dyestuff more quickly than the image dyestuff.
• the intensity of the effect can also be regulated by regulating the duration of the action of the dyestuff bleaching bath either by discontinuing the action of the bath after a predetermined time or by allowing the bleaching bath to act until image dyestutf and metallic silver no longer exist together at any part of the image.
• the excess of metallic silver is converted into silver salt, and simultaneously the unattacked supplementary dyestutf is destroyed.
• the silver salt is dissolved out in a fixing bath, or the two lastmentioned baths may be combined in a single bath of the type of farmers reducer.
• the decoloration of the supplementary dyestuflf takes place more rapidly and completely the higher the pH-value of the ferricyanide bath, but that if the pH- value is too high the image dyestuif may also be attacked.
• the pH-value of the ferricyanide bath is therefore so chosen that it is sufficiently high to bring about the decoloration of the supplementary dyestuff sufficiently rapidly, but not so high as to affect the image dyestufi".
• the supplementary dyestufis are damping dyestuffs their effect on the gradation curve of the silver image is influenced by the nature of the sensitization or, in the case of copying materials, by the wavelength of the copying light.
• the gradation of the dyestuff image can also be further influenced by the action of the supplementary dyestuif on the bleaching of the image dyestufi".
• the present invention enables the partial color images to be very considerably flattened and the shape of the gradation curves to be modified as desired.
• Example 1 A There was cast upon a glass plate measuring 13 by 18 cm. a mixture of 3 ml. of a silver bromide emulsion and 7 ml. of a solution containing 0.28 gram of gelatine and 0.01 gram of the purple dyestuff of the formula B. Upon another glass plate was cast a mixture containing, in addition to the ingredients specified under A, 0.01 gram of the supplementary dyestufl of the formula Each glass plate was exposed with blue light behind a stepped wedge, developed in a Metol-hydroquinone developer to the same silver gamma :0.56), fixed, hardened in aqueous formaldehyde solution, and dried in order to measure the silver image. Both plates were then treated for 30 minutes in a dyestuff bleaching bath having the following composition:
• the plates were then washed, treated in a fixing bath, washed and dried.
• the dyestuif of the Formula 6 can be prepared as folows:
• 165 parts of l-benzyl-l:l-di-(3-methyl-4'-aminophenyl)-ethane are tetrazotized in the usual manner in a solution rendered acid with hydrochloric acid, and coupled with 480 parts of 1-(3'-acetylaminobenzoylamino)- 8-hydroxynaphthalene-3:6-disulfonic acid in a solution rendered alkaline with sodium carbonate.
• the resulting purple dyestutf is filtered off and purified in the usual manner' In the form of the free acid it corresponds to the above Formula 6. It is easily soluble in water, does not diffuse in gelatine, has a high luminosity, has a good compatibility with silver halide emulsions, can be bleached to pure White, and has a good fastness to light.
• the 1 benzyl-l 1-di-(3-methyl4'-aminophenyl)-ethane used as starting material can be prepared as follows:
• a mixture of 320 parts of l-amino-Z-methylbenzene, 300 parts by volume of concentrated hydrochloric acid and 134 parts of phenyl-acetone is stirred, and the temperature of the mixture is raised from 60 C. to C. in the course of 4 hours. Distillation is then brought about by raising the temperature to C,, during which water and oil are collected in a receiver. The oil is separated and returned to the reaction vessel. The mixture is stirred under reflux for about 8 hours longer at 140 C. The mixture is then taken up in water, rendered strongly alkaline with sodium hydroxide solution, and the precipitated oil is subjected to steam distillation in order to recover the excess of l-amino-2-methylbenzene. The greasy residue remaining in the distillation vessel is dried and recrystallized from cyclohexane. There are obtained about 106 parts of colorless crystals soluble in dilute hydrochloric acid and melting at 110 C. and
• the dyestutf of the Formula 7 can be obtained by (16) OH no coupling diazotized 1-amino-4-diethylaminobenzene with l-phenyl-3-'heptadecyl-5-pyraz0lone-4-sulionic acid.
• a filter layer composed of colloidal silver.
• the photographic material so produced was process by one of, the usual methQdS 9f Carrying out the silver 9 dyestuif bleaching process, a potassium ferricyanide bath being used as the silver bleaching bath.
• the color gradation produced in the layer or layers so modified was flatter, and the color gradation in the other layer or layers was substantially unaffected.
• the step which comprises decreasing the contrast obtained by bleaching at least one of the dyestuffs serving for image formation by means of a supplementary dyestufi which corresponds to the fomula in which R represents a member selected from the group consisting of a benzene radical, a naphthalene radical and a pyrazolone radical containing in one of the positions 1 and 4 relatively to the azo group a substituent selected from the group consisting of a hydroxy group and an amino group, and Py represents the radical of a 5- pyrazolone bound in 4-position to the azo linkage, and by destroying completely said supplementary dyestuff in an oxidizing bath following the bleaching bath.
• a bleachable photographic silver halide emulsion layer for the silver dystufi bleaching method which contains in addition to at least one dyestufl serving for image formation, at the most an equal quantity of at least one supplementary dyestutf of the formula in which R represents a benzene radical which contains a hydroxyl group in para-position to the azo linkage and Py represents the radical of a 5-pyrazolone bound in 4- position to the azo linkage.
• a bleachable photographic silver halide emulsion layer for the silver dyestuff bleaching method which contains in addition to at least one dyestufi serving for image formation, at the most an equal quantity of at least one supplementary dyestuff of the formula in which R represents a benzene radical which contains a hydroxyl group in para-position to the azo linkage and Py represents the radical of a l-phenyl-S-pyrazolone containing a sulfonic acid group in the phenyl radical and bound in 4-position to the azo linkage.
• a bleachable photographic silver halide emulsion layer for the silver dyestutf bleaching method which contains in addition to at least one dyestufi serving for image 10 formation, at the most an equal quantity of at least; one supplementary dyestulf of the formula in which R and Py each represents the radical of a 1- phenyl-S-pyrazolone bound in 4-position t0 the azo linkage, at least one of the phenyl radicals containing a sulfonic acid group.
• a bleachable photographic silver halide emulsion layer for the silver dyestuff bleaching method which contains in addition to at least one dyestuif serving for image formation, at the most an equal quantity of the supplementary dyestuff of the formula 6.
• a bleachable photographic silver halide embulsion layer for the silver dyestuff bleaching method which contains in addition to at least one dyestuff serving for image formation, at the most an equal quantity of the supplementary dyestuff of the formula SOSH HO I 1 -0 References Cited by the Examiner UNITED STATES PATENTS 2,020,775 11/1935 Gaspar 9653 2,219,305 10/1940 Gaspar 96-73 2,221,793 11/1940 Gaspar 9653 2,296,843 9/1942 Gaspar 96--73 2,304,987 12/1942 Young 96-99 2,348,894 5/ 1944 Gaspar 9653 3,053,655 9/ 1962 Dreyfuss et a1 96-20 OTHER REFERENCES

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Cited By (4)

Citations (7)

• 0
  • IT IT649870D patent/IT649870A/it unknown
  • NL NL264609D patent/NL264609A/xx unknown
  • BE BE603666D patent/BE603666A/xx unknown
• 1960
  • 1960-05-12 CH CH543560A patent/CH391464A/de unknown
• 1961
  • 1961-05-09 US US108759A patent/US3223527A/en not_active Expired - Lifetime
  • 1961-05-10 DE DEC24092A patent/DE1137626B/de active Pending
  • 1961-05-10 GB GB17108/61A patent/GB931648A/en not_active Expired
  • 1961-05-10 ES ES0267317A patent/ES267317A1/es not_active Expired

Patent Citations (7)

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