US3340060A - Process for the production of color images by the silver dyestuff bleaching method - Google Patents

Process for the production of color images by the silver dyestuff bleaching method Download PDF

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US3340060A
US3340060A US311235A US31123563A US3340060A US 3340060 A US3340060 A US 3340060A US 311235 A US311235 A US 311235A US 31123563 A US31123563 A US 31123563A US 3340060 A US3340060 A US 3340060A
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bleaching
bath
silver
catalyst
developer
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Meyer Armin
Wartburg Rene Von
Anderau Walter
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BASF Schweiz AG
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Ciba AG
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    • 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

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  • the present invention provides a process for the production of color photographic images by the silver dyestufi bleaching method.
  • this method depends on the fact that dyestufis, especially azo dyestuifs, are destroyed by a suitable treatment in the presence of metallic silver and treatment in a neutral or an acid bath containing a complex-forming agent and a bleaching catlyst.
  • the general conception is that theoretically the bleaching of the dyestuffs proceeds stoichiometrically in accordance with the amount of silver present, four silver atoms being required to destroy one azo group.
  • the gradations of the color component images would depend solely upon the gradations of the developed silver images. However, this is not the case.
  • the gradations of the color component images are dependent on many other factors, for example, on the kind of dyestuffs used, on the colloid layer, on the thickness of the layer, on the manner in which the silver is distributed within the layer, on the composition of the bleaching bath and on the duration of the bleaching process.
  • This invention is based on the surprising observation that specially advantageous effects can be obtained in the production of color photographic images by the silver dyesruii bleaching method with the aid of catalyst when the development is carried out in a bath that contains a dyestutf bleaching catalyst under conditions such that the catalyst plays no essential part in the development process.
  • the photographic material to be used may be, for example, material comprising a layer support, a cyan-color layer, a magneta-color layer and a yellow-color layer disposed one on top of the other in that order, each layer being made of a hydrophilic colloid such as gelatine and containing a latent silver image.
  • the layers can also be present in the material in other sequences; the material can contain colored particles of the mixed-grain emulsion type instead of the layers; the support can be transparent or reflecting, and the material may also contain further layers, for example, adhesive layers, intermediate layers, filter layers and covering layers.
  • This material may also contain the usual emulsion additives such as wetting agents, optical and chemical sensitizers; even small amounts of bleaching catalyst may be present in one or more layers or intermediate layers.
  • the bath in which the latent silver image is developed contains a dyestnff bleaching catalyst. Accordingly, a proportion of the dyestufi bleaching catalyst is taken up by the layers of the photographic material being treated in the developing bath and it remains therein, at least partly, until it becomes active during the bleaching process.
  • the dyestufi bleaching catalysts must take no essen- 3,340,060 Patented Sept. 5, 1967 ice tial part in the development of the latent silver image. This can easily be arranged by using developers virtually incapable of catalyzing the dyestuii bleaching process, which is the case with most of the developers normally used. However, it is also possible to use a dyestuti bleaching catalyst that is not capable of developing a latent silver image in order to meet the requirement that the catalysts should take no essential part in the development process. It is also possible to combine the two conditions just mentioned; that is to say, the developer used is incapable of catalyzing the bleaching process and the catalyst used is incapable of developing a latent silver image.
  • hydroquinone which is widely used, and which, it necessary, may be used together with other developers, for example, Metol.
  • dyestufi bleaching catalysts there may be mentioned phenazines, for example, 2-hydroxy-3- aminophenazine and 2:3-diaminophenazine, but more especially phenazine compounds of the formula in which R represents a naphthalene radical condensed with the azine ring in the manner indicated by the valence lines, which naphthalene radical contains a hydroxyl, amino and/ or an azo group attached to the six-membered ring not directly bound to the azine ring, and R represents a benzene or naphthalene radical bound to the azine ring in the manner indicated by the valence lines.
  • phenazines for example, 2-hydroxy-3- aminophenazine and 2:3-diaminophenazine
  • Quinoxaline, alloxazine and cinnoline can also be used as dyestufi bleaching catalysts.
  • the process of the present invention is carried out by known methods.
  • the dyestufi bleaching bath comprises, as usual, an acid aqueous solution, for example, hydrochloric acid and at least one complex-forming agent, for example, potassium bromide or thiourea.
  • This bath can contain small amounts of bleaching catalyst.
  • the amounts of catalyst that may be present in the material and/or in the bleaching bath must be such that they are not sufiicient to bring about complete bleaching of all the color component images by the image silver present in the time available.
  • a preferred method of carrying out the process of the present invention consists in exposing in the usual manner light-sensitive multilayer material that is colored with azo dyestufis and free from bleaching catalysts, developing it in a bath that contains a bleaching catalyst, fixing it, washing it with water, bleaching it in a bath free from catalyst, and then freeing it from residual silver in the usual manner.
  • the fixing bath between the developing bath and dyestuflz' bleaching bath may be omitted.
  • the method can also be applied in reversal processes, the catalyst being added to the second developing bath.
  • the catalyst exerts a very uniform action in the various layers and exhibits favorable behaviour in respect of diffusion, so that no over-bleaching of the top layer occurs as in the usual processes.
  • EXAMPLE 1 7 The following layers are applied successively to a cellulose acetate film providedwith an'adhesive layer:
  • Gelatine intermediate layer Green-sensitive silver bromide emulsion in gelatine that contains the magenta dyestufi of the formula 17m, noi s
  • Green-sensitive silver bromide emulsion in gelatine that contains the magenta dyestufi of the formula 17m, noi s
  • Blue-sensitivesilver bromide emulsion in gelatine that contains the; yellow dyestutf of the formula and as precipitating agent amixture comprising a reactionproduct of dicyanodiamidine and formaldehyde, a
  • the images obtained are designated hereinafter as red wedge, green wedge, blue wedge and grey wedge.
  • the film is hardened in a formaldehyde bath, washed with water and then developed for 6 minutes in the follow- 5 ing developer, the temperature of the developer and all subsequent baths being .24? C.
  • the film is; then treated in the following stop fixation bath without an intermediate wash with water:
  • the film is washed with water. for 3 minutes and then bleached in a dyestuff bleaching bath having the following composition:
  • the time of treatmentin-this bath is so selected that it is just suflicient to bring about complete bleaching of the dyestuffs -t ll. ers th hp ces osthi hly pose the said time of treatment having been determined by tests. It is as follows:
  • the film is then washed with water, the residual silver rehalogenated in a copper nitrate bath made strongly acid with hydrochloric acid, washed again, fixed, washed and then dried.
  • the dyestuff in the blue-sensitive layer can be prepared by diazotizing 2-aminonaphthalene-4:8-disulfonic acid, coupling the diazo compound with 1-amino-2-methylbenzene, and treating the aminomonoazo dyestutt so obtained with phosgene.
  • bleaching catalysts are added to this developer, the amounts being in milligrams per liter of developer:
  • EXAMPLE 3 A film of the composition given in Example 1 is exposed, hardened in a formaldehyde bath, washed with water and then developed for 4 minutes in developer I, which developer contains 30 milligrams of 2-amino-3- hydroxy-phenazine hydrochloride per liter as bleaching catalyst. The film is Washed with water for 2 minutes and then treated for 4 minutes in the dyestuif bleaching bath as described in Example 1 which is free from bleaching catalyst. In accordance with Example 1, the residual silver is then rehalogenated and fixed. The time of treatment in the dyestuff bleaching bath is so selected that it is just sufficient to bring about complete bleaching of the dyestuffs in all layers at the areas most highly exposed, which time is determined by experiment.
  • Emax, and E represent the strongest and Weakest exposures respectively that are capable of being copied.
  • the color densities are measured with a Macleth-Ansco- Densitometer in transmitted light; the gamma values correspond to the straight parts of the gradation curves.
  • Boas 7 EXAMPLE 4i Multi-layer silver dyestuff. bleaching materialfcast on baryta paper and hardened while casting, but otherwise having the same composition as 'inExample 1 is exposed and developed. The silver is converted into silver chloride in a bleaching bath andthe resulting chloride dissolved out selectively. The silver bromide that remains is exposed in diffused light and-developed for 10 minutes in a developer having the following composition:
  • This solution also contains 25 milligrams'of the dyestuft' bleaching catalyst 3-amino-4-hydroxybenzo[u]phenazine- 2-sulfonic acid'ofthe'Formula- 7.
  • This bath also contains 1 milligram of the dyestutf bleachirig catalyst 3-(4'.-snlfophenylazo) 4 hydroxybenzohz] phenazine-2-sulfonic acid of the Formula 6.
  • the layer is washed with water and the excess silver converted into silver chloride in known manner with the aid of a copper-containing bleaching bath, and the. chloride dissolved out in a subsequent fixing bath.
  • the resulting color image exhibits high color densities atthe highly exposed'areas after the above treatment, and the dyestulfs are bleached out at the areas of low exposure.
  • EXAMPLE 5 A silver bromide-silver iodide emulsion that contains the black dyestufi of the formula O-OHr and a hardening agent is cast on to a photographic paper;
  • a sheet of type-Written paper is brought intocontact with the said photographic paper in such a manner thatthe back of the original lies 'on thephotographic layer.
  • the composite specimen is exposed for 15 seconds in a When the2c3-dimethylquinoxaline solution is omitted from the developer, no dyestuff bleaching takes place and a completely black sheet of paper is obtained.
  • the step which comprises carrying out the development in a bath that contains a developer not capable of catalyzing the dyestufi bleach-ing process and also a quinoxaline as a dyestuif bleaching catalyst.
  • the step which comprises carrying out the developmentin a. bath that contains hydroquinone as a developer and also a phenazine as a dyestutf bleaching catalyst.
  • the step which comprises carrying, out the development in a bath that contains hydroquinone as a developer and also 2,-amino-3-hydroxyphenazine.as a,
  • the step which comprises carrying out the development in a bath'that contains hydroquinone as a. developer 7 and also 3.-amino-4-hydroxybenzo lyst.

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

Description

United States Patent 3,340,060 PROCESS FOR THE PRODUCTION OF COLOR IMAGES BY THE SILVER DYESTUFF BLEACH- ING METHOD Armin Meyer and Ren von Wartburg, Basel, and Walter Anderan, Aesch, Basel-Land, Switzerland, assignors to Ciba Limited, Basel, Switzerland, a Swiss company No Drawing. Filed Sept. 24, 1963, Ser. No. 311,235
7 9 Claims. (CI. 96-53) The present invention provides a process for the production of color photographic images by the silver dyestufi bleaching method. As is known, this method depends on the fact that dyestufis, especially azo dyestuifs, are destroyed by a suitable treatment in the presence of metallic silver and treatment in a neutral or an acid bath containing a complex-forming agent and a bleaching catlyst. The general conception is that theoretically the bleaching of the dyestuffs proceeds stoichiometrically in accordance with the amount of silver present, four silver atoms being required to destroy one azo group. It could therefore be assumed that, in material containing a plurality of silver component images, the gradations of the color component images would depend solely upon the gradations of the developed silver images. However, this is not the case. The gradations of the color component images are dependent on many other factors, for example, on the kind of dyestuffs used, on the colloid layer, on the thickness of the layer, on the manner in which the silver is distributed within the layer, on the composition of the bleaching bath and on the duration of the bleaching process.
Proposals 'for independently controlling the gradations of the color component images, especially for obtaining flatter gradations, have already been made, for example, by the incorporation of non-diliusing bleaching catalysts in the light-sensitized layers, by the use of oxidizing agents in the bleaching process and by the use of several bleaching baths.
This invention is based on the surprising observation that specially advantageous effects can be obtained in the production of color photographic images by the silver dyesruii bleaching method with the aid of catalyst when the development is carried out in a bath that contains a dyestutf bleaching catalyst under conditions such that the catalyst plays no essential part in the development process.
The photographic material to be used may be, for example, material comprising a layer support, a cyan-color layer, a magneta-color layer and a yellow-color layer disposed one on top of the other in that order, each layer being made of a hydrophilic colloid such as gelatine and containing a latent silver image. The layers can also be present in the material in other sequences; the material can contain colored particles of the mixed-grain emulsion type instead of the layers; the support can be transparent or reflecting, and the material may also contain further layers, for example, adhesive layers, intermediate layers, filter layers and covering layers. This material may also contain the usual emulsion additives such as wetting agents, optical and chemical sensitizers; even small amounts of bleaching catalyst may be present in one or more layers or intermediate layers.
In the process of the invention the bath in which the latent silver image is developed contains a dyestnff bleaching catalyst. Accordingly, a proportion of the dyestufi bleaching catalyst is taken up by the layers of the photographic material being treated in the developing bath and it remains therein, at least partly, until it becomes active during the bleaching process.
The dyestufi bleaching catalysts must take no essen- 3,340,060 Patented Sept. 5, 1967 ice tial part in the development of the latent silver image. This can easily be arranged by using developers virtually incapable of catalyzing the dyestuii bleaching process, which is the case with most of the developers normally used. However, it is also possible to use a dyestuti bleaching catalyst that is not capable of developing a latent silver image in order to meet the requirement that the catalysts should take no essential part in the development process. It is also possible to combine the two conditions just mentioned; that is to say, the developer used is incapable of catalyzing the bleaching process and the catalyst used is incapable of developing a latent silver image.
It can easily be deter-mined by tests whether or not developers and dyestutf bleaching catalysts meet these requirements. As an example of a developer having no catalytic action on dyestuif bleaching there may be mentioned hydroquinone, which is widely used, and which, it necessary, may be used together with other developers, for example, Metol.
As examples of dyestufi bleaching catalysts there may be mentioned phenazines, for example, 2-hydroxy-3- aminophenazine and 2:3-diaminophenazine, but more especially phenazine compounds of the formula in which R represents a naphthalene radical condensed with the azine ring in the manner indicated by the valence lines, which naphthalene radical contains a hydroxyl, amino and/ or an azo group attached to the six-membered ring not directly bound to the azine ring, and R represents a benzene or naphthalene radical bound to the azine ring in the manner indicated by the valence lines. Such compounds and processes for their preparation are described in U.S. patent application Ser. No. 306,690, filed Sept. 5, 1963, now U.S. Patent 3,318,700 (Swiss patent application No. 10,928/ 62).
Quinoxaline, alloxazine and cinnoline can also be used as dyestufi bleaching catalysts.
The process of the present invention is carried out by known methods.
The dyestufi bleaching bath comprises, as usual, an acid aqueous solution, for example, hydrochloric acid and at least one complex-forming agent, for example, potassium bromide or thiourea. This bath, too, can contain small amounts of bleaching catalyst. However, the amounts of catalyst that may be present in the material and/or in the bleaching bath must be such that they are not sufiicient to bring about complete bleaching of all the color component images by the image silver present in the time available.
Accordingly, a preferred method of carrying out the process of the present invention consists in exposing in the usual manner light-sensitive multilayer material that is colored with azo dyestufis and free from bleaching catalysts, developing it in a bath that contains a bleaching catalyst, fixing it, washing it with water, bleaching it in a bath free from catalyst, and then freeing it from residual silver in the usual manner. The fixing bath between the developing bath and dyestuflz' bleaching bath may be omitted.
The method can also be applied in reversal processes, the catalyst being added to the second developing bath.
In the process of the present invention the catalyst exerts a very uniform action in the various layers and exhibits favorable behaviour in respect of diffusion, so that no over-bleaching of the top layer occurs as in the usual processes.
Finally, in contrast to the processes known hitherto it is possible, in the process of the invention, to harmonize the color gradations in such a manner that, when exposed-to white light, fiatcolor gradation curves'a-re obtained that run parallel to one another, and that, when exposed to one spectral color, steep gradation curves are obtained: Thus, when a color chart that includes a neutral.
grey wedge is copied an imageis obtained in which the grey wedge is correctly reproduced and in which the colors exhibit a high degree of saturation. Should this process lead to too stronga bleaching of the lower layers, a balanced bleach can be obtained ,by dividing the catalyst between the developer and the dyestufl bleaching bath.
The following examples illustrate the invention. Unless otherwise stated, the parts and percentages are by weight.
EXAMPLE 1 7 The following layers are applied successively to a cellulose acetate film providedwith an'adhesive layer:
(1) Red-sensitive silver bromide emulsion in gelatine that contains the cyan dyestutf ofthe formula v (2) Ooo-HN on (IL-CH3. HO
N=NON=N Ho,s- S03H I (2) Gelatine intermediate layer. (3) Green-sensitive silver bromide emulsion in gelatine that contains the magenta dyestufi of the formula 17m, noi s (4)'- Yellow filter layer that contains the dyestufi'of the formula (5) Blue-sensitivesilver bromide emulsion in gelatine; that contains the; yellow dyestutf of the formula and as precipitating agent amixture comprising a reactionproduct of dicyanodiamidine and formaldehyde, a
small amount of sodium formate and sodium bisulphite.
(6) Gelatine protective layer.
h sfil iis xp ed o m s inds ey d e. as,
ol ow 1st exposure: in red light only 2nd exposurezin green light only 3rd exposure: in blue light only I 4th exposure: in red, green and blue lightpthe exposures being so arranged that the 4th wedge appears a neutral rey ite",p cessin o I I I 0 C H: H: C
Hots
4 The images obtained are designated hereinafter as red wedge, green wedge, blue wedge and grey wedge. The film is hardened in a formaldehyde bath, washed with water and then developed for 6 minutes in the follow- 5 ing developer, the temperature of the developer and all subsequent baths being .24? C.
veloper:
1st experiment 10 milligrams of 2-amino-3-hydroxyphenanzine hydrochloride. 7
2nd experiment 4 milligrams of 3 (4? sulfophenylazo) --4 hydroxybenzohdphenazine-Z-sulfonic acid (of. the Formula 6.
S 0 11 HgN SOH 3rd experiment 6 milligrams of 3-amino-4-hydroxybenzo[a]phenazine- 2-sulphonic acid of the Formula '7. V
The film is; then treated in the following stop fixation bath without an intermediate wash with water:
Sodium acetate grams 10 Thiourea I do Glacial acetic acid cc 20 5o Bulked with water to 1000 cc.
The film is washed with water. for 3 minutes and then bleached in a dyestuff bleaching bath having the following composition:
Potassium bromide Q grams 100 Thiourea do 10 Hydrochloric acid (conc.) cc 1,25% aqueous solution of the addition product of 70 4 35 mols of ethylene oxide with 1 mol of octadecyl alcohol 'c 10 Bulkedwith water to 1000 cc;
The time of treatmentin-this bath is so selected that it is just suflicient to bring about complete bleaching of the dyestuffs -t ll. ers th hp ces osthi hly pose the said time of treatment having been determined by tests. It is as follows:
The film is then washed with water, the residual silver rehalogenated in a copper nitrate bath made strongly acid with hydrochloric acid, washed again, fixed, washed and then dried.
When repeating these experiments but omitting the bleaching catalyst in developer I, only a very slight degree of dyestuti bleaching is obtained.
In three further experiments the same procedure as above is adopted but omitting the developers l-phenyl-3- pyrazolidone and hydroquinone in developer I. In this process no silver image is visible before the bleaching bath; on completion of the process no bleaching of the dyestuffs is observed.
The dyestuff in the blue-sensitive layer can be prepared by diazotizing 2-aminonaphthalene-4:8-disulfonic acid, coupling the diazo compound with 1-amino-2-methylbenzene, and treating the aminomonoazo dyestutt so obtained with phosgene.
The catalyst 3-(4'-sulfophenylazo) 4 hydroxybenzo- [a]phenazine-2-sulfonic acid of the formula HOsS N/ I \N Holsis obtained from the foregoing catalyst by splitting the azo group with sodium hydrosulfite.
EXAMPLE 2 The experiments described in Example 1 are repeated using the following developer 11:
Grams Metol 2.5 Sodium sulfite (anhydrous) 30 Hydroquinone 2.5 Sodium metaborate Potassium bromide 0.5
Bulked with water to 1000 cc.
The following bleaching catalysts are added to this developer, the amounts being in milligrams per liter of developer:
1 st experiment 4 milligrams of 2-amino-3-hydroxyphenazine hydrochloride.
2nd experiment 4 milligrams of 2-amino-3-hydroxyphenazine hydrochloride.
4 milligrams of 3-(4'-sulfophenylazo)-4-hydroxybenzo- [a1phenazine-2-sulfonic acid of the Formula 6.
3rd experiment at the areas most highly exposed is as follows:
Minutes 1st experiment 10 2nd experiment a '10 3rd experiment 12 Only a very slight degree of bleaching is achieved when the bleaching catalyst is omitted in developer II. No silver image is visible and no dyestuff bleaching takes place when the two developers Metol and hydroquinone are omitted in developer II.
EXAMPLE 3 A film of the composition given in Example 1 is exposed, hardened in a formaldehyde bath, washed with water and then developed for 4 minutes in developer I, which developer contains 30 milligrams of 2-amino-3- hydroxy-phenazine hydrochloride per liter as bleaching catalyst. The film is Washed with water for 2 minutes and then treated for 4 minutes in the dyestuif bleaching bath as described in Example 1 which is free from bleaching catalyst. In accordance with Example 1, the residual silver is then rehalogenated and fixed. The time of treatment in the dyestuff bleaching bath is so selected that it is just sufficient to bring about complete bleaching of the dyestuffs in all layers at the areas most highly exposed, which time is determined by experiment.
For comparison purposes, a series of 4 exposures produced in the same manner as above is subjected to the same treatment, with the exception that the developer I is free from bleaching catalyst and the same catalyst was added to the dyestuff bleaching bath in an amount of 2 milligrams per liter. The minimum time required to bring about complete bleaching is 8 minutes.
The results obtained in the two experiments in respect of gradation (gamma value) and extent of exposure are listed in the following table, the extent of exposure being designated with Alog E.
Alog E=10g mma min.
whereby Emax, and E represent the strongest and Weakest exposures respectively that are capable of being copied. The color densities are measured with a Macleth-Ansco- Densitometer in transmitted light; the gamma values correspond to the straight parts of the gradation curves.
| Boas 7 EXAMPLE 4i Multi-layer silver dyestuff. bleaching materialfcast on baryta paper and hardened while casting, but otherwise having the same composition as 'inExample 1 is exposed and developed. The silver is converted into silver chloride in a bleaching bath andthe resulting chloride dissolved out selectively. The silver bromide that remains is exposed in diffused light and-developed for 10 minutes in a developer having the following composition:
Bulked with water to 1000 cc.
This solution also contains 25 milligrams'of the dyestuft' bleaching catalyst 3-amino-4-hydroxybenzo[u]phenazine- 2-sulfonic acid'ofthe'Formula- 7.
The-layer-is"then'washed with-Water'for 1 minute and bleached-for 8' minutes in a batlr having the following composition;
Water "millimeters", 75.0 Potassium bromide grams .100 Hydrochloric acid (37% strength) m illimeters 70 Thiourea grams 10" Bulked with water to LOOO'millimeters.
This bath also contains 1 milligram of the dyestutf bleachirig catalyst 3-(4'.-snlfophenylazo) 4 hydroxybenzohz] phenazine-2-sulfonic acid of the Formula 6.
'The layer is washed with water and the excess silver converted into silver chloride in known manner with the aid of a copper-containing bleaching bath, and the. chloride dissolved out in a subsequent fixing bath. The resulting color image exhibits high color densities atthe highly exposed'areas after the above treatment, and the dyestulfs are bleached out at the areas of low exposure.
EXAMPLE 5 A silver bromide-silver iodide emulsion that contains the black dyestufi of the formula O-OHr and a hardening agent is cast on to a photographic paper;
A sheet of type-Written paper is brought intocontact with the said photographic paper in such a manner thatthe back of the original lies 'on thephotographic layer.
The composite specimen is exposed for 15 seconds in a When the2c3-dimethylquinoxaline solution is omitted from the developer, no dyestuff bleaching takes place and a completely black sheet of paper is obtained.
What is claimed is: 1. In a process for the production of c010! Photographic fl f I I s'oai 1101's images by. the silver 'dyes tufi bleaching method with the aid of catalysts, the step which comprises carrying out the development in a bath that contains a dyestufl? bleaching catalyst and undervconditions such that the catalyst playssnoessential part inthe developmentprocess.
2. In a process forthe production ofcolor photographic images by thesilver dyestufi bleaching method with the aid of catalysts, the step which comprises carrying out the development in a bath that contains a developer not,
capable of catalyzing the dyestuif bleaching process and also a dyestuif bleaching catalyst.
3. In a process for the production of color photographic aid of catalysts, the step which comprises carryingout the.
development in a bath that contains a developer not ca-, pable of catalyzing the dyestuflf bleaching process and also a'phenazine as a dyestutf bleaching catalyst.
5. Ina process for the production of colorphotographic images by thesilver dyestutf bleaching-method withtheaid of catalysts, the step which comprises carrying out the development in a bath that contains a developer not capable of catalyzing the dyestufi bleach-ing process and also a quinoxaline as a dyestuif bleaching catalyst.
6. In a process-for the production of multi-color photographic images by the silver dyestutf bleaching method with the aid of catalysts, the step which comprises carrying out the developmentin a. bath that contains hydroquinone as a developer and also a phenazine as a dyestutf bleaching catalyst.
7. In a process for the production of multi-color photographic images by the silver dyestuif bleaching method with the aid of catalysts, the step which comprises carrying, out the development in a bath that contains hydroquinone as a developer and also 2,-amino-3-hydroxyphenazine.as a,
dyestufi bleaching catalyst.
with the aid of catalysts, the step which comprises carry- HsC-O SOBH ing out the development in a bath that contains hydroquinone as a developer andalso 3-(4l-sulfophenyl'azo)-4-hydroxybenzo[aJphenazine-Z-sulfonic acid as a dyestuft bleaching catalyst.
9. In a process for-the production of multi-color photo! graphic images by the silver dyestufi"bleachingmethod.
with the aid of catalysts, the step which comprises carrying out the development in a bath'that contains hydroquinone as a. developer 7 and also 3.-amino-4-hydroxybenzo lyst.
References Cited UNITED-STATES PATENTS' .J. TRAVIS BROWN, Primary Examiner.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,340 ,060 7 September 5 1967 Armin Meyer et a1.
It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
In the heading to the printed specification, after line 8 insert Claims priority, application Switzerland, Oct. 5, 1962, 11760/62 Signed and sealed this 22nd day of October 1968 (SEAL) Attest:
EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.
Attesting Officer

Claims (1)

1. IN A PROCESS FOR THE PRODUCTION OF COLOR PHOTOGRAPHIC IMAGES BY THE SILVER DYESTUFF BLEACHING METHOD WITH THE AID OF CATALYSTS, THE STEP WHICH COMPRISES CARRYING OUT THE DEVELOPMENT IN A BATH THAT CONTAINS A DYESTUFF BLEACHING CATALYST AND UNDER CONDITIONS SUCH THAT THE CATALYST PLAYS NO ESSENTIAL PART IN THE DEVELOPMENT PROCESS.
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US4152157A (en) * 1977-05-02 1979-05-01 Fuji Photo Film Co., Ltd. Color image forming process
US4197123A (en) * 1977-07-21 1980-04-08 Ciba-Geigy Ag Process for the production of masked positive color images by the silver dye bleach process
US5418116A (en) * 1993-12-07 1995-05-23 Eastman Kodak Company Image toning of black-and-white images formed utilizing color dye forming couplers

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US2004625A (en) * 1930-11-07 1935-06-11 Bela Gaspar Method of producing photographic dyestuff images
US2221793A (en) * 1938-05-17 1940-11-19 Gaspar Bela Method of producing photograph dyestuff pictures
US2278984A (en) * 1939-03-29 1942-04-07 Chromogen Inc Method of treating color photographic materials
US3156561A (en) * 1958-06-03 1964-11-10 Ciba Geigy Corp Method of producing color photographic pictures
US3278303A (en) * 1961-12-20 1966-10-11 Ciba Ltd Process for the preparation of multicolored images by the silver dyestuff bleaching method

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US2004625A (en) * 1930-11-07 1935-06-11 Bela Gaspar Method of producing photographic dyestuff images
US2221793A (en) * 1938-05-17 1940-11-19 Gaspar Bela Method of producing photograph dyestuff pictures
US2278984A (en) * 1939-03-29 1942-04-07 Chromogen Inc Method of treating color photographic materials
US3156561A (en) * 1958-06-03 1964-11-10 Ciba Geigy Corp Method of producing color photographic pictures
US3278303A (en) * 1961-12-20 1966-10-11 Ciba Ltd Process for the preparation of multicolored images by the silver dyestuff bleaching method

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4152157A (en) * 1977-05-02 1979-05-01 Fuji Photo Film Co., Ltd. Color image forming process
US4197123A (en) * 1977-07-21 1980-04-08 Ciba-Geigy Ag Process for the production of masked positive color images by the silver dye bleach process
US5418116A (en) * 1993-12-07 1995-05-23 Eastman Kodak Company Image toning of black-and-white images formed utilizing color dye forming couplers

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