DE1547759B1 - Silver dye bleaching process - Google Patents

Description

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The invention relates to a silver dye bleaching process through which the alkaline activator solution is introduced interrupted in a silver halide-containing color photo-winding. The pH will be like this graphic material after exposure and de-diminished that the dye imagewise in the presence wrap at least one dye in the presence of one of the silver complex-forming compounds in the silver complex-binding agent Connection in the area of the 5 ken, in which metallic silver is present, image-silver image is bleached. is fairly bleached.

The known silver dye bleaching process (see. German- According to an advantageous embodiment of the

see patent specification 1167 652) is based on the fact that the method of the invention, which is particularly useful for Agree organic dyes during a bleaching process of color photographic images in cameras Process depending on the amount of photo- ίο is suitable as follows: graphically generated image silver are bleached. A recording material with an exposed

The disadvantage of the known over-color bleaching silver halide emulsion layer, which has a bleachable drive is that several processes contain dye or are in contact with one for its implementation Steps and several treatment baths are required, is necessary in the presence of a silver halide are. Although the well-known multi-stage SiI-15 winder connection with an alkaline activator dye bleaching process brought into contact with color images of excellent solution, so that the pH so Quality leads, but have greatly increased the relatively large number that the developable silver halide of Process stages and the relatively long developer is reduced to metallic silver. At least The alkaline activator solution is used in one application, arranged in particular in the area of the Ama- 20 breakable containers, found expensive photography. This embodiment of the method of the invention

The object of the invention is to simplify manure thus requiring means to zer-silver dye bleaching process to indicate which the broke, so that its content spreads uniformly over the Distribution of colored images in a simple exposed silver halide emulsion layer in a short time Way and can be used directly in the camera. The emulsion layer of the recording sheet detects can be. rials is then brought into contact with a development

The subject matter of the invention is based on a SiI- clock that has at least one cation output bleaching process in which a silver exchanger contains an effective acidic compound. The enthalide containing color photographic material after winding tape interrupts the development the exposure and development at least one color reduction of the pH value of the emulsion layer substance in the presence of a silver complex-forming agent by ion exchange with the salt of the acid that bond in the area of the silver image is bleached either in the emulsion layer or the active, and is characterized in that the vator solution or both. Develop with an alkaline activator or developer. The strong acid salt can be used at any time

Winding solution in the presence of a salt takes place after bringing the emulsion layer into contact with it The activator or developer solution acts as a monochrome photographic solution to the developing belt in the emulsion layer Material with a tape being brought d. H. in making the emulin a water-soluble or water-swellable layer or by adding hydrogen ions to the alkaline activator solution donating cation exchanger is incorporated.

contains, is brought into contact and the type and 40 The breakable container can at the developer concentration of the salt can be chosen so that the lung band or the photographic material bebeim Cation exchange resulting free acid of the solidified, what after bringing the beSalzes into contact the pH of the material exposed in the color photographic recording material with the container Material penetrated activator or developer tape and the development tape of the container broken solution lowered to at least 3. 45 and recording material and development

The method of the invention thus enables the band to come into contact with one another so that they see Production of colored images, starting from the colored contents of the container evenly between entphotographic Materials consisting of a winding tape and material can be spread. Layer support as well as a SiI applied thereon to carry out the method of the invention

Over halide emulsion layer, which contains the salt of an acid 5 ° is suitable for example a three-part photographic and which contains a bleachable dye in phisches material, the three parts of which are composed of: Contact is made by the emulsion layer after the
Development of the silver image with a ribbon in con-

clock is brought, which a cation exchanger, a light-sensitive recording material with d. H. contains an acidic compound capable of being 55 on a support and at least one thereon Hydrogen ions through the cations of the salt in supported photosensitive silver halide wells Replace emulsion layer, thereby removing the sion layer, which is covered with a bleachable dye pH of the activator or developer solution is connected. The indication "is in connection" is brought to a value at which in the presence of one means that the dye is in the photosensitive silver complex forming compound an imagewise 60 silver halide emulsion layer itself is present Fading of the dye in the areas of the metal or in one with the silver halide emulsion layer lischen silver takes place. colloid layer in contact, the alkali-per-

The fading of the dye is preferably carried out. The photosensitive material can also fes in the presence of a catalyst. a variety of silver halide emulsion layers

The salt does not need to have in the emulsion layer 65, which contains various bleachable dyes Rather, it can also be kept in the activator solution or in contact with the colloid layers to be available. hen that contain the dyes, by choosing

By reducing the pH value, the various bleachable dyes become multicolored

images can be made. The photosensitive material can thus be either one or more photosensitive Have silver halide emulsion layers which contain bleachable dyes, or else the bleachable dyes can be accommodated in separate layers, each with one or several silver halide emulsion layers are in contact.

Part II

contains a breakable container that contains an alkaline activator solution, through which the pH value of the emulsion layer or layers is increased to a value at which a reduction from developable silver halide to metallic silver, provided a silver halide developing agent is available.

Part III

of the photographic material consists of an "acidic" developing belt, which is an exchange the hydrogen ions with the cations of the salt of a strong acid, that of the emulsion layer or incorporated into the emulsion layers by bringing them into contact with the developing belt became. The strong acid salt can be added to the emulsion layer or layers during their production have been incorporated. The salt can also be added to the alkaline activator solution.

According to a particularly advantageous embodiment, the breakable container is attached to the development belt. On the other hand, however, it is also possible attaching the breakable container to the photosensitive recording material. Possibly the three parts of the photographic material may be arranged in a package form with the emulsion layer of the part I is arranged opposite the acidic developing belt and wherein further the frangible Container is arranged between the photosensitive recording material and the acidic developing belt.

If necessary, parts I and III can be rolled up together, with part II being part of the is a part, preferably part III.

Those photographic materials have proven to be particularly advantageous which contain at least have three photosensitive emulsion layers facing either blue, green, or red Light sensitized and correspondingly non-diffusing yellow, purple and blue-green dyes contain.

In the drawing is a photosensitive suitable for carrying out the method of the invention photographic material consisting of Parts I, II and III shown. Part I consists of the Layer support 1, on which a blue-sensitive emulsion layer 2 is arranged, which is a bleachable contains yellow dye. There is a green-sensitive emulsion layer 3 thereon which contains a bleachable magenta dye. Then again there is disposed a red-sensitive emulsion layer 4 containing a bleachable cyan dye contains.

Optionally, instead of an emulsion layer in each case two different emulsions with different sensitivities can be used to create a larger exposure space for the material.

It may be advantageous to place hydrophilic emulsion layers between the individual emulsion layers To arrange colloid existing intermediate layers, which may contain a wide variety of additives can, such as ballasted quinones, reduce the diffusion of reduced dye bleach catalysts to prevent between layers.

Part III of the material consists of a development belt with a layer support 5 with one applied thereon hydrophilic colloid layer 6 made of gelatin which contains a free acid and one applied thereon Control layer 7.

Part II consists of a breakable container, from an envelope 8, which has been broken open by suitable means can be, in which the alkaline activator solution 9 is located.

For the preparation of the photographic material of the invention, conventionally known light-sensitive ones can be used Emulsions can be used.

For the preparation of the photographic material of the invention, the usual known ones can be bleached Dyes, preferably non-diffusing dyes, are used. This also includes the so-called dye formers, d. H. Compounds that appear only during the development process of the photographic Materials become colored and form dyes. Under "non-diffusing" dyes are also to understand compounds that by means of a suitable mordant, such as those from the U.S. Patent 2,882,156 cannot be made diffusible.

Advantageous neutral dyes which can be used in the context of the process of the invention are the azo dyes known from British Patent 999,996.
The bleachable dyes are preferably contained in the emulsion layers. If necessary, however, it can also be advantageous to incorporate a bleachable dye into an alkali-permeable layer which is in contact with the emulsion layer. Such an arrangement can, if necessary, achieve increased sensitivity, in particular if the layer containing the bleachable dye is arranged below the emulsion layer.
The pH of the alkaline activator or developer solution which has penetrated into the emulsion layer or layers is preferably about 9.0. A wide variety of alkaline solutions are suitable for carrying out the process, e.g. B. sodium or potassium hydroxide solutions. If necessary, compounds which control the development, such as potassium bromide, can be added to the solutions. The activator and developer solutions can also be incorporated the usual additives that are used in conventional developer solutions or activator solutions, such as compounds which facilitate the spreading of the solution, such as saponin and other surface-active compounds, antifoggants and stabilizers.

For processing the photographic material of the invention, conventionally known photographic ones can be used Developer compounds are used. These developer compounds can be

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As is known, in the emulsion layer (s) of sodium meta-t-butyl-benzenesulfonate and the entphotographic material, or speaking potassium salts, and also salts of sulfuric acids, are incorporated into alkaline solutions. acid, sulfonic acid, phosphoric acid, the phosphonic acid. If appropriate, it can be advantageous to _{incorporate a compound into the acid or acids of the formula ROP (OH) 2} and the trichloroacetic acid in the emulsion layers.

ben that have both a developing function and it has been found to be particularly beneficial when

has the function of a bleachable dye. a photographic material is used which Such compounds should not be diffusing, as the salt contains potassium chloride, whereby the dye part of the molecule can be bleached. In an advantageous manner, these salts can also be

got to. ίο Activator or developer solutions, namely in

Among silver complex binding compounds are concentrations of about 0.5 to 2 moles of salt per to understand those compounds that are added to either liters of solution. The cheapest con-silver ions Dissolving and decentering the salts from the emulsion layer depends on the strength of the acid distant or react with the silver ions in the way. In any case, the salt should be in such a condass these become insensitive to light and transparent. 15 centration used that the pH of the The complexing agents can reduce the activator or developer solution to less than 3.0, are incorporated or optionally reduced in development - preferably less than 2.0 or 1.5, lungsband be available. But you can also when the ion exchange has taken place. Preferable both The type of salt, salt concentration and type of salt are set in the activator solution as well as in the development Lungsband are brought to the application. Typical, 20 and concentration of cation exchange such to carry out the method of the invention from one another that the pH occurred to below 1.0 Complexing agents are, for example, dimethyl.

lolthiourea; Trimethylolthiourea; cyclic The function of the development band thus exists

Thioureas, e.g. B. 1,3-bis- (| S-hydroxyethyl) -imidazo- in it, to interrupt the development and the bleachlidin-2-thione and l - (/ 3-hydroxyethyl) imidazoliden- 25 to activate the process.

2-thion. The carrier material of the tape used can

Before the recording material with the or for example made of paper, a polyolefin, ζ. Β. developed silver halide emulsion layers with polyethylene or polypropylene, a polycarbonate the developing belt, or a cellulose ester, e.g. B. cellulose acetate buryrate the emulsion layer (s) must pass the salt of a 30. When using film supports is strong acid. The salt can make it useful to apply a layer to this first the emulsion or emulsions during their coating in which the cation exchanger is adjusted can be incorporated or can be anchored by means of the alka. If necessary, the deletion can Activator or developer solution supplied to the winding tape, however, also from a self-supporting will or eventually both the emulsic acid cation exchange polymer (s) exist, additional layers incorporated as well as with the alkaline, for example, a cross-linked polystyrene with free Activator or developer solution are supplied. acidic groups, e.g. B. sulfonic acid groups. Suitable The salt of the strong acid reacts with the cation exchange membranes, like them acidic components of the development tape, for example from the journal Nature, Vol. 165 the pH of the emulsion layer or the Emul 40 (1950), p. 568, are known.

Sion layers during the development process The development tape needs to be reduced after it has been converted will. There is no ion exchange between the emulsion layer to be developed see the acidic components of the development tape being more self-supporting. It is only essential and the salt of the strong acid, the salt that the tape so long with the emulsion layer in loses its cation and an acid is formed. 45 can stay in contact that an ion exchange, i. H. This causes the pH of the emulsion layer to exchange the cation of the salt with the or emulsion layers diminished so that the hydrogen atoms of the developing belt take place-fading of the dye can find through the metallic.

According to a preferred embodiment, there is silver in the presence of the silver complex-binding compounds

loyalty is facilitated. 50 the development belt from a layer support

Suitable salts of strong acids are those which, after a hydrophilic layer has been applied thereon, the regression of the free acid contains the pH value in a polymer and a free acid. Suitable activator solutions which have penetrated the emulsion layers are, for example, poly or developer solutions containing acid groups to less than 3, preferably to mere, sulfonic acids with ballast groups, phosphonic less than 2.0. 55 acids with ballast groups of the formula ROP (OH) ₂ ,

It is preferable to use a photographic material such as dodecanesulfonic acid and hexadecanephosphone which is a salt of an acid with an ionic acid. Ballast groups here mean groups by containing sation constants that are greater than 10 ~ ³ . which limits the mobility of the acid or

It has proven to be particularly advantageous to make it impossible in aqueous media to if a photographic material is used, 60 Sulphonic acids have been found to be particularly suitable which proved to be an optionally substituted ammonium salt ballast groups, especially high one Acid or an alkali metal or alkaline earth molecular monomer acids, such as, for example metal chloride, bromide, nitrate, sulfate, sulfonate, oc-sulfostearic acid. However, they are also suitable contains phosphate or phosphonate. polymeric cation exchange resins such as

Also suitable are quaternary ammonium salts, 65 resins which have been produced by condensation such as tetraalkylammonium chloride. Im of phenolsulfonic acid with formaldehyde or poly single Examples include: tetramethylstyrenesulfonic acids with para-formaldehyde. The acids or tetrabutylammonium chloride, sodium chloride, can be used in various ways in the development

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tape anchored, preferably by incorporating 45 mg of silver in the form of silver chloro-

the acid remains in an alkali permeable layer, such as bromide,

for example a hydrophilic colloid layer of 400 mg photographic gelatin,

for example gelatin, polyvinyl alcohol or an an- 25 mg of a pink dye with the

their colloid, as shown, for example, in column 13 of the 5 color index no. 25380,

U.S. Patent 3,039,873. 60 mg poly-a-methylallylaminoguanidine

Optionally, the development tape can also acetate and

a silver halide complex binding compound containing 35 mg 5-3c- [N, N-bis- (j3-hydroxyethyl) amino] -

keep. methyl - 2 - methylhydroquinonedime-

A developing io thyl sulfate can also advantageously be used.

tape can be used, which was then applied over the acidic emulsion layer Layer has a colloid layer, the so-called 1 second long by a step wedge with density control layer serves and has the purpose of decrementing the 0.3 by means of a at a distance winding the exposed silver halide in such a way as to set up a photographic magnification of 46 cm control that the development is finished before 15 exposure lamp and then 3 seconds the ion exchange between hydrogen ions and long in an activator solution A of the following additional cations he follows. composition submerged:

Activator solutions A

for example gelatin, polyvinyl alcohol and mi- "

Compositions of polyvinyl alcohol and polyvinyl acetate 20. ™ y ^ · · · ·, 3.5 g

be used. For the preparation of such control 2-hydroxy-3-aminophenazm 0.6 g

layers, however, are also suitable, for example, the sodium chloride ·········· 100.0 g

in column 13 of US Pat. No. 3,039,873, sodium m-nitrobenzenesulfonate .. 25.0 g

written binders. Potassium bromide .. .. 5.0 g

^{Such controls with water to 1 liter} have proven to be particularly advantageous

layers proved to be at least about 500 mg of the photosensitive recording material

Contain binding agent per 0.0929 m ^{2 of} carrier surface or then in contact with a component for 45 seconds

are about 0.0127 mm thick. winding tape, which is made of a cellulose

In a particularly advantageous manner, use is made of a photo-acetate film support and a graphic material applied to it which consisted of a catalyst layer which contained 2-hydroxy-3-aminophenazine ^{per 0.0929 m 2 of support surface of the bleaching process:}

^eiu * ^el ·,, "...". 560 mg polyvinyl alcohol,

The catalyst can very generally m an emul- _{4Q a} _s _u ifostearic acid and

sion layer, the alkaline developer or acti- 600 mg thiourea vator solution or used in the development belt 35

will. If necessary, the catalyst can also be used in several places after the separation of recording material, for example and developing tape from each other remained in the urine of an emulsion layer, in the alkaline, photosensitive material a positive developer solution and in the developing tape. The color picture back. All the silver was removed. Catalysts oxidize metallic silver to 40. Silver ions and are thereby reduced themselves. The ß e 1 s ρ 1 e 1 2 reduced catalyst then again undergoes an oxy- There was another recording material of the dation reaction with the dye. Produced in this structure described in Example 1, with the oxidation process, the dye is bleached, with the exception, however, that as a black-and-white developer, the catalyst in its original state is reoxy- 45winding 3,6-bis- (2-hydroxyethyl) -2,3 , 4,5,6,7-hexahydrode. 1,8-dioxy-3-diazophenanthrene was used. The compounds which contain metallic silver and are suitable to form silver ions for the oxidation of excess layer applied to the layer support and are ^{made up of: per 0.0929 m 2 support area} : which in their reduced form do not react with the bleaching dyes of _{the specified developer} Also known as so-called 50 ₂ 5 mg of a dye with the color-named silver bleaching compounds, typical index no. 25380 silver bleaching compounds are, for example, the o- ₆₆ poly- ^ methylall'ylaminoguanidine and m-nitrobenzenesuonic acids and difusible acetate azo dyes. Other typical silver bleaching 50 mg of silver halide compounds, for example, in the British _55,400 photographic gelatin. Patent 533,190. These compounds can also be added to the emulsion layer (s). The alkaline activator or developer solution was applied to the exposed recording material, then a 0.0050 cm thick layer of the activator solution B given in the following development tape or several of these individual elements was applied:

elements are incorporated. 60

Activator solution B

1% carboxymethyl cellulose

B e i s ρ i e 1 1 solution 100 ml

50 ⁰¹ ₀ sodium hydroxide solution .. 4 ml

A silver 65 2-hydroxy-3-mainophenazine 0.15 g

chlorobromide emulsion layer in such a way- potassium bromide 0.5 g

wear that on a support area of 0.0929 m ² ent- benzotriazole 0.05 g

fell: sodium chloride 10.0 g

After the activator solution B has acted for A developing tape of the type described in Example 1 was applied to the recording material for 5 seconds Composition pressed on. The contact time was 40 seconds. After separating recording material and developing tape became more excellent in a positive color image in the recording material Quality visible. The silver had been removed.

Example 3

IO

A three-color recording material was produced with the following structure:

On a white pigmented cellulose acetate support were in the. in the following order:

A red sensitive gelatin-silver bromoiodide emulsion layer, a green sensitive gelatin-silver bromoiodide emulsion layer and a blue-sensitive gelatin-silver bromoiodide emulsion layer.

DierotempfindlicheGelatine-silver bromoiodide emulsion layer was coated such that on a support surface of 0.0929 m ² 108 mg red-sensitive silver bromoiodide, 203 mg of gelatin, 63 mg of poly-a-methylallylaminoguanidinacetat and 25 mg of a blue dye with der.Eolor index no. 24410 were omitted.

The green-sensitive gelatino-silver bromoiodide emulsion layer was coated such that on a support surface of 0.0929 m ^2, 108 mg green-sensitive silver bromoiodide, 206 mg of gelatin, 66 mg of poly-a-methylallylaminoguanidinacetat and 26 mg of a red dye with the color index no. 25,380 were accounted for.

The blue-sensitive gelatin silver bromoiodide emulsion layer was coated such that on a support surface of 0.0929 m ² 108 mg blue-sensitive silver bromoiodide, 310 mg of gelatin, 100 mg of poly-a-methylallylaminoguanidinacetat and 35 mg of a yellow dye having the color index no. 29025 were omitted.

The recording material obtained was then immersed for 3 minutes in a solution which contained 50 g of the developer 4 - {«- [N, N-bis (/ 3-hydroxyethyl) amino] methyl} -2-methylhydroquinone dimethyl sulfate per liter of water . Thereafter, the recording material was air-dried. Subsequently, it was exposed for 3 seconds by means of a photographic magnifying lamp set up at a distance of 46 cm through a step wedge with density steps of 0.3. A filter was located between the magnifying lamp and the recording material. The exposed recording material was then immersed for 40 seconds in an activator solution C of the following composition:

Activator solution C

Water 1 liter

50% sodium hydroxide solution .. 5 ml

2-Hydroxy-3-aminophenazine 1.5 g

Sodium chloride 100.0 g

Potassium bromide 5.0 g

Then the recording material was for 2 minutes on a developing belt of the im Example 1 specified composition pressed.

After separating the recording material and the developing tape, the recording material a positive color image is visible. The silver was gone been.

Example 4

The process described in Example 3 was repeated, but this time instead of the developing belt described in Example 1, a developing belt was used which, on a cellulose acetate film support, had a layer consisting of per 0.0929 m ^{2 of support area} :

2 g of a commercially available cation exchange resin,
900 mg thiourea and
500 mg polyvinyl alcohol

contained.

The results obtained corresponded to those of Example 3.

Example 5

It was a multi-layer, monochrome, color photo graphic Recording material produced with the following structure:

A gelatin layer was first applied to a white pigmented cellulose acetate layer support in such a way that the following bleaches out onto ^a support area of 0.0929 m a:

120 mg photographic gelatin,
63 mg poly-a-methylallylaminoguanidine

acetate and
22 mg of a blue dye with the

Color index no. 24410.

A red-sensitive silver bromoiodide emulsion layer was then applied to this layer in such a way that a support area of 0.0929 m ^{2 covered} :

108 mg silver as red-sensitive silver bromoiodide,
150 mg photographic gelatin,

80 mg hydroquinone,

20 mg of l-phenyl-3-pyrazolidone and
0.8 mg sodium bisulfite.

The resulting recording material was then recorded for 3 seconds by means of a at a distance of A magnifying lamp set up to 46 cm is exposed through a step wedge with density levels of 0.3. Afterward The material became a development tape of the one described in Example 1 for 2 minutes Composition pressed after a 0.010 cm thick layer on the recording material beforehand a viscous activator solution D of the following composition:

Activator solution D

1% carboxymethyl cellulose

solution 1 liter

50% strength sodium hydroxide solution, ^e .. 16 ml

Sodium chloride 100 g

2-Hydroxy-3-aminophenazine 1.6 g

1% 5-methylbenzotriazole solution 60 ml
Methylaminoethanol sulfite complex

(20 ° / ₀ solution) 5 ml

After the recording material and the developing tape had been separated, the recording material a positive color image is visible. The silver was gone been.

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60

11 12

τ. · · Ι (■ 54 mg red-sensitive silver bromoiodide,

^p 200 mg gelatin,

The procedure described in Example 5 was repeated for 35 mg of the one on page 1 of the USA patent, but this time a blue ribbon described in development 1 829 673 was used, which had a control layer, 5 green dye,
through which the diffusion time is increased. The 90 mg poly-Ä-methylallylaminoguanidine developing tape was prepared by removing an acetate and
Development band of the 80 mg of 1-phenyl-3-pyrazolidone described in Example 1.
Composition such with a coating

mass was coated that on a support surface io The green-sensitive silver bromoiodide emulsion

of 0.0929 m ² 570 mg of polyvinyl alcohol and 570 mg of layer was applied in such a way that on a carrier

Polyvinyl acetate was omitted. area of 0.0929 m ² accounted for:

. Furthermore, it was an activator solution D of ₅₄ g _rünem pfindlichesSilberbromojodid _s

The composition described in Example 5 uses 200 ms gelatin

applies, but the methylaminoethanol sulfite 15 ₂ 6 mg of a red dye with the

complex omitted and the sodium chloride by Color Index No. 25380

100 g of sodium nitrate was replaced ₆₆ poly ^ -methylanylarmnoguanidine-

It became a positive color image of excellent acetate

Maintain quality. All the silver was removed and 60 mg of hydroquinone

^been - ²⁰ 15 mg of l-phenyl-3-pyrazolidone.

Example 7 The blue-sensitive silver chlorobromide emulsion

layer was applied in such a way that on a carrier

A light-sensitive recording material with an area of 0.0929 m ² accounted for:

In the structure described in Example 1, 54 _{mg of} blue-sensitive silver chlorobromide,

Example 1 described, exposed and then 200 ms gelatin

developed by being in contact with a de- 35 mg of a yellow dye with the

Wrapping tape was brought, which consisted of a Color Index No. 29025

CeUulose acetate film carrier with a layer which per _m poly-a-methylailylaminoguamdinacetat,

0.0929 m ² bearing area contained:, 30 _{40 m} | Hydroquinone and

3.7 g of a commercially available polystyrene sulphon 10 mg of 1-phenyl-3-pyrazolidone.

fonsaureharzes, _{the gelatin interlayers WUR} d _s such up

onri ^{S rc} "y ^acr y ^isaure '.. carried that on a support area of 0.0929 m ²

200mg a-sulfostic acid and? ? Λ °

materials was used to record a multicolored

Between the developing belt and the recording image using a camera from the material was cured a 0.015 cm thick layer of a vis-USA.-Patent 2,543,160 te; written type Activator solution E of the following composition 40 applies, with an exposure index of ASA 5 brought: was applied.

Activator solution E The exposed recording material was then

3% carboxymethyl cellulose- developed by being in contact with a

L. ' ^{00 JJ} " _T. , Winding tape of the supply described in example 7

solution 1 liter

winding band in the example
45 composition was brought. The contact time

Na ₂ SO ₃ 10 g

Sodium chloride 60 g

II b ^ uTl5 St ^ b ^ n ^ mpe ^ r ^^ C

1.6 g was used an activator solution F in a

Thickness of 0.020 cm on the recording material

“ _{W Λ} , _{n was} applied and the following composition

P "" ™ ⁶ " ¹⁰ ' ^Og 5o possessed:

The results obtained corresponded to those of activator solution F.

Example 1. Water 500 ml

3-amino-2-hydroxyphenazine 1.6 g

B e ι s ρ ι e 18 sodium hydroxide 28 g

⁵⁵ Sodium sulfite (anhydrous) 10 g

There was a 3-color recording material potassium chloride 50 g

following structure: 6-nitrobenzimidazole '.'. '.'. '.'. '.'. '.'. '.'. 6 g

On a white pigmented cellulose acetate carrier ascorbic acid 0 20 g

were in the following order the following layers of dimethyl sulfoxide !!!!!!!!!!! "" 2'ml

th applied: a red-sensitive Silberbromo- 6o _Hy droxyäthylcellulose "......... 40 g

iodide emulsion layer, a gditine layer, a green one _{filled with} water to 1 liter

sensitive silver bromoiodide emulsion layer, a pH value of 13 2

Gelatin layer and a blue-sensitive silver

chlorobromide emulsion layer. After activation, development tape and

The red-sensitive silver bromoiodide emulsion 65 recording material separated from one another. The layer was applied to the substrate in such a way that viscous activator solution was ^{removed from the surface that the recording material was removed from a substrate area of 0.0929 m 2} , whereupon a 3-color positive image of excellent quality fell

became visible. All of the silver was removed simultaneously with the formation of the color image.

Example 9

A 3-color recording material of the structure described in Example 8 was produced, but this time a layer of cellulose phthalate was applied to the material which contained 750 mg of sodium ^{benzene sulfonate on a carrier surface of 0.0929 m 2.} The cellulose phthalate layer was easily removed because the cellulose acetate was soluble in alkali.

A sample of the recording material was then used for recording an image according to the procedure in Example 7 method described is used.

The exposed material was then in contact with a developing belt for 1.5 minutes brought the composition described in Example 7 at 24 ° C. Between recording material and developing belt, a 0.020 cm thick layer of an activator solution was placed in its composition the activator solution F of Example 8 with the exception that it did not contain any potassium chloride, corresponded.

After activation, the recording material and the developing belt were separated from each other. the viscous activator solution and the coating layer were peeled off from the surface of the recording material, whereby in the recording material a three-color image of the recorded object became visible. All the silver had been removed.

Claims (8)

Claims: 35 1. Silver dye bleaching method in which in a silver halide color photographic material after exposure and development, at least one dye in the presence of a silver complex-forming agent Connection in the area of the silver image is bleached, characterized in that, that the development is carried out with an alkaline activator or developer solution in the presence of a salt, after exposure the activator or developer solution, the color photographic material with a tape that a cation exchanger which releases hydrogen ions in a water-soluble or water-swellable layer contains, is brought into contact and the type and concentration of the salt is selected in such a way that that the resulting free acid of the salt during the cation exchange has the pH value of the in the Activator or developer solution that has penetrated color photographic material to at least 3 humiliated. 2. The method according to claim 1, characterized in that a photographic material is used which contains a salt of an acid with a dissociation constant of greater than 10 ^-3 . 3. Process according to Claims 1 and 2, characterized in that one is a photographic Material used which is an optionally substituted ammonium salt of an acid or a Alkali metal or alkaline earth metal chloride, bromide ,. nitrate, sulfate, sulfonate, phosphate or phosphonate contains. 4. Process according to Claims 1 to 3, characterized in that there is a developing belt used, which consists of a layer support and an alkali-permeable layer applied to it consists of a strongly acidic polymer, a sulfonic acid with a ballast group, as a cation exchanger or contains a phosphoric acid with a ballast group. 5. Process according to Claims 1 to 4, characterized in that one is a photographic Material used that contains potassium chloride as salt. 6. Process according to Claims 1 to 5, characterized in that there is a developing belt used, which consists of a carrier and a layer of polyvinyl alcohol in which a-sulfostearic acid is dispersed. 7. The method according to claims 1 to 6, characterized in that one is a photographic Material used that contains 2-hydroxy-3-aminophenazine as a catalyst in the bleaching process. 8. Process according to Claims 1 to 7, characterized in that one is a photographic Material used that consists of a layer support and at least three alkali-permeable layers applied to it Colloid layers, one of which has blue-sensitive silver halide and contains or in contact with a nondiffusible bleachable yellow dye one of which further comprises green-sensitive silver halide and one does not diffusible bleachable magenta dye containing or in contact with such and of which further comprises a red-sensitive silver halide and a non-diffusing one contains bleachable blue-green dye or is in contact with such, wherein the three layers each contain such an amount of a salt of an acid that, in the free Acid transferred, reduce the pH of the layers so much that the dyes are in the presence a silver complex-forming compound, and that one on the material after imagewise exposure, in the presence of a silver halide developing agent, for An alkaline activator solution can act on the development of the silver halide to metallic silver before developing the material with the developing belt. 1 sheet of drawings