DE2315759A1 - METHOD AND DEVELOPER FOR DEVELOPING HIGH-CONTRAST PHOTOGRAPHIC DIFFUSION TRANSFER MATERIALS - Google Patents

Description

PATENT LAWYERS

DR. E. WIEGAND DIPL-ING. W. ΗΙΞΜΑΝΝ DR. AA. KÖHLER DIPL-ING. C GEHNHARDT

MÖNCHEN HAMBURG

»« »Ο MONKS 2,

MATHILDENSTRASSE

W 41 543/73 March 29, 1973

Fuji Photo Film Co., Ltd., Minami Ashigara-shi, Kanagawa (Japan)

Process and developer for developing high contrast diffusion transfer photographic materials

The invention relates to a method and developer compositions for developing high contrast diffusion transfer photographic materials; it concerns in particular a method and developer compositions for production of high-contrast images through diffusion transfer.

09841/108 ¹ ?

In the field of graphics, high-contrast, light-sensitive materials used for phot ο graphic Reproduction of line drawing images and halftone images (halftone dot images). For example, by printing a continuous tone original onto a photographic sensitive lith material through a screen and developing the same using a so-called infectious developer (see. "Photographic Processing Chemistry", pages 163 to 165, published by Focal Press Co., 1966) produces a halftone image (halftone image).

However, since the process for developing the sensitive Lith material is a negative-positive process, it is not possible to generate images using a positive-positive process. As a result, when creating images, after a positive-positive process, such as in the case of Generation of positive images from a negative original, duplicating (printing) using a separator intermediate negative be performed. It would therefore be advantageous and labor-saving from an economic point of view to when print drawing images and halftone images directly from the original could be made without the need for the intermediate negative production step.

The following briefly describes the well-known, highly developed diffusion transfer development described. Having a photosensitive material that has an image receiving layer, the colloidal Contains metal nuclei which act as physical development nuclei and a S over halide emulsion layer on the image receiving layer has been exposed to light, that becomes

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Material - treated with an alkaline solution for development, which contains a silver halide solvent and a reducing agent, whereby the exposed portion in the emulsion layer is chemically developed by the reducing agent. On the other hand, the unexposed silver halide in the Developer solution dissolved and diffused into the image receiving layer, in which the diffused silver halide is reduced around the colloidal metal nuclei and deposited to form a positive silver image. Accordingly, in a diffusion transfer process the dissolution of the silver halide, the diffusion of the silver complex salt and the physical development around the colloidal nuclei represent essential stages. A more detailed explanation of the diffusion transfer process can be found published in "Photographic Silver Halide Diffusion Processes" from The Focal Library, 1972.

The aim of the present invention is therefore to develop developer compositions for generating high-contrast images, especially line drawing images and halftone images (raster images) according to a positive-positive process, in particular a diffusion transfer process. Another object of the invention is to provide developer compositions for producing halftone dot images with excellent halftone photographic properties which are excellent in durability. Another object of the invention is to provide a diffusion transfer method indicate, with the help of which it is possible to achieve the above objectives, especially high-contrast images to create.

It has now been found that the above objectives can be achieved

30 984 17 108 7

if you can use the well-known diffusion transfer developer Imidazo! Compounds clog.

The invention accordingly relates to developer compositions for a silver salt diffusion transfer process, which are characterized in that they contain one or more Contain imidazole compounds.

The invention is described below with reference to FIGS. to 3 of the accompanying drawings, in which the vertical axis is the concentration of the developer and the horizontal axis indicate the exposure time (log E).

In the case of the silver salt diffusion transfer process, that becomes Silver halide in the exposed portion of the negative material developed by a developer compound in the developer, while the silver halide in the unexposed part with reacts with a silver halide solvent in the developer forming a soluble silver complex salt which diffuses into the positive material (the image receiving layer) and becomes in a silver precipitation seed layer of the positive material, precipitates with the formation of silver images. Although this process has been known for a long time, they point to it available positive images have a very low contrast. It is therefore not possible to use this method to produce line drawing images and halftone images such as those used in the graphic arts be applied, to produce (to reproduce) «. For example, if the diffusion transfer process for creating halftone images is applied, a density gradient section (seam or edge) occurs, which is disadvantageous in plate production

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However, if the above developer iridazole compounds are added to the formula given below, the contrast of the positive images obtained increases completely considerable and no areas (districts) with medium density are reproduced. Also, the exposure area of the foot part of the characteristic curve (hereinafter referred to as cutting off the foot part) is shortened.

In the above formula, R _{1 represents} a hydrogen atom, an alkyl group, a substituted alkyl group, a vinyl group or an allyl group, R ~ a hydrogen atom, an alkyl group or a substituted alkyl group, R-, a hydrogen atom or an alkyl group, and R, a hydrogen atom, a Alkyl group or a substituted alkyl group. It is known that imidazole groups react with silver ions to form salts.

It is assumed that the function of the imidazo! Compounds in the present invention is related to the effect of this salt formation. It is accordingly believed that the Imidazo! Compounds are effective as long as they are in the system used are soluble. Quaternary salts are according to the invention also effective. As for the substituted alkyl groups, it should be noted that any alkyl substituent, the the imidazo! compounds are water-soluble or alkali-soluble

309841/1087

Liability can be used according to the invention. Most preferred are alkyl groups with up to 12 carbon atoms in the alkyl radical (substituted or unsubstituted) used. For example, a with lauryl (a C-. O-alkyl radical) substituted imidazo! as completely water soluble considered in view of the fact that lauryl pyridinium chloride is water soluble. .

Examples of compounds of the general formula given above, which also includes the quaternary salts, are imidazole, 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-amylimidazole, 1-isoamyl ^9- methylimidazole, 4 , 5-dimethylimidazole, 2-ethylimidazole, 1-methylimidazole, 2,4,5-trimethylimidazole, 4-hydroxymethyl 1-5-methylimidazo 1,4- (2-hydroxyethyl) -5-methylimidazole, 1-allyl -2-methylimidazole, l-vinyl-2-methylimidazole, 1-vinyl-2-methylimidazole methyl tosylate, l-benzyl ~ 2-methylimidazole methyl tosylate and l-benzyl-2-methylimidazole methyl iodide.

The preferred embodiments of the invention therefore include both imidazo groups per se and imidazole groups with a Alkyl, an alkyl or substituted alkyl group or groups, where the alkyl group (s) contains up to 12 carbon atoms and optionally by, for example, hydroxy, carboxy, Acyl or aryl groups is substituted, with hydroxy, carboxy and acyl groups being preferred substituents.

It is sufficient if at least one of the above-mentioned compounds is used is included in the developer, although mixtures thereof can be used. However, there the required amount varies depending on the compound, they will be in one

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appropriate concentration to achieve the desired result used. An effective range is at least about 1 g, typically / about 1 to about 250 g, preferably 1 to IQOg, especially at 5 to 70 g per liter of developer. In many * len process is generally a concentration of about 10 to about 150 g per liter required, so that a certain Overlap is found outside the preferred range.

The above mentioned Imidazo! Compounds are in an aqueous alkaline η medium soluble. Therefore, the inventive Developers are made by simply adding the imidazole compounds to known diffusion transfer developers or developers is added to an aqueous solution along with a developer composition. Besides, these connections are not just opposite aqueous alkali solutions stable, but they also have the Property that they promote the durability (storage stability) of the developer. Accordingly, from the standpoint of Developer's stability is an advantage. "

The diffusion transfer developer compositions used in the present invention have almost the same composition as the known diffusion transfer developers, they contain but one or more imidazo! compounds. The developer compositions namely represent an alkaline solution, the at least one developer compound and a silver halide solution, contains solvent. They are described, for example, in U.S. Patents 2,543,181, 2,662,822 and 2,857,276. In general comprises a developer solution for a diffusion transfer process the following components:

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(1) developer,

(2.) Silver halide solvent with optionally (3) one Development accelerator, (4) preservative, (5) retarder, (6) antifoggant,

The developer mainly consists of an organic reducing agent and acts to reduce the latent image formed in the silver halide layer with formation of a visible (metal) image. In general, benzene derivatives, Naphthalene derivatives and the like having a reducing Function used. Developer combinations used particularly preferably according to the invention are 3-pyrazolidone compounds or aminopheno! compounds with polyhydroxybenzene compounds. Representative examples of these compounds are as follows:

3-Pyrazolidone Compounds (A,) j 1-phenyl-3-pyrazolidone, 1-p- (eolyl-3-pyrazolidone, 1-phenyl-> 4-methyl-3-pyrazolidone, i-phenyl-4 _i .4-dimethyl -3-pyrazolidone and lp-chlorophenyl-3-pyrazolidone, although similar 3-pyrazolidones can of course also be used. ■ - ■■■ "

Aminogheno! Compounds (A ~) s N-methyl-p-aminopheno 1, p-aminophenol, 2,4-diaminophenol ₉ p-benzylinophenol _s 2-methyl-p-aminophenol and 2-I-hydrocyme'thyl-p ° aminophenol _J whereby, of course, similar aminophenols can also be used «,

PolYhy_droxvbenzο! Compounds (B): hydroquinone, pyrocatechol, chlorohydroquinone, pyrogallol, bromohydroquinone, isopropy! Hydroquinone, toluhydroquinone, methylhydroquinone _? 2,3-dichlorohydroquinone, 2,5-dimethylhydroquinone and 2,3-dibromohydroquinone, although similar polyhydroxybenzenes can of course also be used.

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In diffusion transfer development, this is done by exposure generated latent image in the negative layer, which consists of a silver halide emulsion, developed and nearly at the same time the unexposed silver halide becomes negative Emulsion layer reacted with a silver halide solvent to form a diffusible silver complex salt, the amount of which depends on that of the exposed silver halide, and the silver complex salt thus produced diffuses into the image receiving layer, in which the diffused salt comes into contact with the colloidal germs and is then reduced with the formation of a silver image in this layer. Accordingly, the silver halide solvent is an element useful for To achieve the diffusion of the silver complex salt must be added, which is, for example, an alkali metal thiosulfate, such as sodium thiosulfate, potassium thiosulfate and the like, or around an alkali thiocyanate and the like.

In general, if desired, in the inventive Developer composition preservatives, such as sulfites, sulfite buffer, such as sulfite addition products, elalides such as potassium bromide, alkaline agents such as sodium hydroxide, or the usual ones Additives such as antifoggants, surface-active agents and water softeners (e.g. sodium hexametaphosphate and ethylenediaminetetraacetic acid), be incorporated. The pH of the developer compositions according to the invention is during their Use in the alkaline range and is preferably 9.5 to 13.0.

The developer compositions according to the invention are in the form of a liquid developer, an organic solvent

309841/1087

- ■ .- ίο -

holding condensed developer and the like, in the form of a viscous developer containing hydrophilic resins and in the form of a powder developer used when the developer components be mixed. In other words, when a developer containing imidazo compounds is used in development is used, it falls within the scope of the present invention.

In addition to the additives mentioned above, the inventive Developer compositions optionally also contain any hydrophilic alkali-soluble resins. Preferred Resins are e.g. methyl cellulose, carboxymethyl cellulose, hydrox}? · - ethyl cellulose, ethyl cellulose, alginates, polyvinyl alcohol, polyvinylpyrrolidone and the same.

The developer solutions according to the invention can be in the form of highly concentrated solutions, dissolved in organic solvents, are stored, the concentrated solutions when used with water in certain desired proportions be diluted. Hydrophilic organic solvents are used to produce such concentrated developer solutions used, in which the respective components are dissolved. These organic solvents must be sufficiently miscible with water and examples of this are glycols such as ethylene glycol, Diethylene glycol, triethylene glycol, tetraethylene glycol and the like, Cellosolves, such as methyl cellosolve, ethyl cellosolve and the like, alcohols, such as methyl alcohol, ethyl alcohol, propyl alcohol, Butyl alcohol and the like, as well as ketones such as acetone, methyl ethyl ketone and the like. These organic solvents

3 are preferably used in an amount of 5 to 300 g per 1000 cm of the developer used. In general, the degree of concentration of the developer is within the range

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from about 2 to 5 times the strength.

The diffusion transfer photographic materials of the invention consist of a support, an image-receiving element (or an image-receiving layer), the silver diffusion transfer nuclei contains, and a photosensitive silver halide element (a negative emulsion layer), wherein the'image-receiving layer and the photosensitive silver halide layer (element) can be separated from one another or combined with one another (as a multilayer).

As the photosensitive silver halide, various kinds of silver halides can be used, such as silver chloride, Silver bromide, silver bromide chloride, silver iodide, silver iodide chloride, Silver iodobromide, silver iodobromide chloride and the like. High contrast emulsions of silver chloride, silver bromide or Silver bromochloride and the like, e.g., silver bromochloride emulsions containing 5 to 30 mole percent silver bromide, are particularly preferred. Those emulsions are preferably used in which the exposed silver salt is developed quickly, x-y while the unexposed one Silver salt quickly forms a complex compound which is quickly reduced in the image-receiving layer. As a binding agent Gelatine is generally used, but gelatine derivatives such as phthalated gelatine, hydrophilic polymers, such as polyvinyl alcohol and polyvinyl pyrrolidone, as well as mixtures thereof, can be used. Vinyl polymer compound dispersions can be added to the binders be incorporated. Examples of such compounds are water-soluble polymers of alkyl acrylate, Alkyl methacrylate, acrylic acid, sulfoalkyl acrylates, sulfoalkyl methacrylates and the same. Other known binders can also be used with success, and the binders are

309841/1087,

not limited to gelatin.

Preferably a high silver halide to binder ratio is used, with a weight ratio of 0.4 to 0.6 or so is particularly advantageous in reproduction of portraits as used in the graphic field.

If desired, commonly used additives such as Sensitizers, sensitizing dyes, antifoggants, hardeners, surface-active agents and other additives, can be added to the silver halide emulsions.

Examples of sensitizing dyes which can be used in the present invention e are those of the cyano group, the merocyanine group, the complex (trinuclear) cyanine group, the complex (trinuclear) Merocyanine group, the stilbene group and the hemicyanine group. group. As sensitizers, the speed of sensitization can be used accelerating compounds such as quaternary ammonium compounds, polyethylene glycol or thioether groups are used or any suitable known method in preparing the silver halide emulsion, e.g. in ripening using natural active gelatin or in sensitization using various Kinds of sulfur, selenium or tellurium compounds or gold compounds are applied. Of course they need to be photosensitive Materials which are treated with the developer compositions of the invention from high contrast photographic Emulsions be made.

309841/1087

Representative for carriers used according to the invention are e.g. cellulose ester films, polyvinyl acetal films, polystyrene films, polyethylene terephthalate films, Cellulose triacetate films and other related film-forming resin materials as well as glass, paper, metal and the like. In addition, one with polyethylene, polystyrene or polypropylene can also be used coated paper can be used as a carrier.

The silver precipitating agent added to the image-receiving element it can be any known physical development or chemical precipitation agent. These agents include heavy metals, especially colloidal heavy metals, and the salts of these metals, salts with Anions, the silver salts with a lower solubility than the silver halides in the photographic to be developed

can,
Element form / as well as non-diffusible polymeric substances with functional groups that can be combined with silver ions to form insoluble substances. Representative examples of such precipitating agents (deposition agents) are suitably those containing sulfide groups, selenide groups, polysulfide groups, polyselenide groups, thiourea and derivatives thereof, mercapto compounds, tin (II) halides, colloidal metals such as silver, gold, platinum * palladium and the like including silver sulfide “Nickel sulfide, sodium sulfide, colloidal sulfur, thiosinamine, stannous chloride, chloroauric acid, and the like, all of which are commonly used in the art. The sensitometric properties of the resulting image can be adjusted to a certain extent by appropriately selecting the type of silver precipitating agent and the concentration thereof. The most effective concentration

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the silver precipitating agent is about 0.01 mg / m to about

0.1 g / m, although these numerical values are not to be understood as limiting are. In addition, the silver image layer or the emulsion layer can be any conventional silver halide solvent desired or developer compound can be added. The germs or chemical deposition agents are used in any suitable binder as is commonly used for this purpose is dispersed, preferably in gelatin and the like.

It is known that the addition of the above-mentioned compounds to photographic elements and compositions to many Effect leads and use is made of these in practice. For example, it is known that imidazo1 and imidazölderivate check the formation of fog when they are phot ο graphic Elements are added and that they reduce the rate of development delay and change the color of the developer if they are added to developer compositions (cf. "Photographic Chemißtry", page 98, paragraph 5, by Shinichi Kikuchi). It is also already known that silver halide light-sensitive materials in the presence of alkyl-substituted or hydroxyalkyl-substituted imidazoles, whereby the development is accelerated (see French patent specification 2 029 043). .

It should be pointed out, however, that both have been common up to now Diffusion transfer s development of Imidazo! Compounds per se have not been used in a workable way and themselves if the compounds were used, so was their quantity

3 very low (about 0.001 to 1 g per 1000 cm of developer solution). According to the invention, the imidazo compounds are now in one

309841/1087

larger amount than usual added, creating high contrast positive images can be obtained with a good short foot effect (cutting off the foot part), one of the represents characteristic features of the present invention, and thereby also the contrast and the maximum density and the like can be increased. In particular, pointed out that in the case of the generation of a halftone dot image (halftone dot image) the halftone image obtained has the same quality as the image obtained using the usual high-contrast photosensitive materials is obtained because the

The formation of framing (edge formation) is greatly reduced. Also is it is possible to produce positive halftone dot images.

When the developer composition of the present invention is applied to a multilayer diffusion transfer photosensitive material is applied, the negative emulsion layer is easily stripped from an image receiving layer to form a positive one Picture, because the hardening of the negative emulsion layer is prevented by the quinones.

As indicated above, the present invention is of technical importance because the developers of the invention together. Settlements practical effects can be achieved that could not be foreseen from the prior art. Accordingly the present invention is very useful for producing positive line drawing images and halftone images.

While the main features of the present invention have been generally described above, in the following examples, which explain the invention, but are not intended to limit it to some preferred embodiments of the

309841/1087

finduhg described. All thickness specifications given therein are unless otherwise stated, based on the thickness of the dry layer,

example 1

After treating the surfaces of a 0.18 mm thick polyethylene terephthalate film with a solution containing sulfuric acid, phosphorous acid and potassium dichromate of the following composition

H ₂ SO. 400 cm ³ "N.

HLPO. 200 cm ³ ί

„„ _Λ - -, „ ■ f 50 C, contact time

K ₀ Cr ₀ O, 70 g ο Tf

2 2 7? I minutes

Water . ad 3000 cm J

an antihalation layer was applied to a surface, while on the other surface a dispersion of gelatin in an organic solvent of the type given below Composition applied and dried at 120 ° C for two hours was formed to form an intermediate layer with a thickness of 0.2 ii. ·

Gelatin, Ig

Water Ig

Acetic acid ■ Ig ■

Methanol 20 g

Acetone 60 g

Methylene chloride 10 g

Tetrachloroethane 5g

Phenol 5g '

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On the surface coated in this way, an aqueous Gelatin solution containing a nucleating substance for physical development, of the following composition and dried at 60 ° C for 60 minutes to form a hydrophilic diffusion transfer image-receiving layer a thickness of 0.5 ai.

Nickel sulfide gelatin dispersion 0.4 g

(Nickel sulfide 5 χ ΙΟ " ⁴ wt .-%
Gelatin 0.5% by weight)

Gelatin 0.4 g

Water 100 g

1% aqueous sodium dodecylbenzenesulfonate

solution 0.4 g

1% aqueous chromium acetate solution 0.4 g

A panchromatically sensitized, high-contrast, uncured gelatin silver bromide chloride emulsion (containing 70% silver chloride and 1 mol of silver per kg of emulsion) was applied to this image-receiving layer and dried to form a film 5 η thick. In addition, a 1% gelatin aqueous solution was applied thereon to form a 1 Å thick protective layer, and dried to form a photosensitive material.

Using this light-sensitive material, a sample was prepared by photographing a sensitometric Step wedge (a Fuji exposure lamp from Fuji Photo Film Co. Ltd. was used as the light source, the exposure conditions were the followingί energy output of the lamp: 10 volts, distance between lamp and light-sensitive material; 1 m, loading

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exposure time: 1 second), developing using a diffusion transfer developer of those shown below

-O.

Composition at 25 C for 1 minute, washing with warm water at 30 C and removing the emulsion layer forming a positive image as a silver image.

5 g 10 G 14th G 10. g. 1, 0 g 2 ecm 10 G ad 1 liter

Composition of the developer:

1-phenyl-3-pyrazolidone Hydroquinone

Sodium hydroxide

Ascorbic acid

Potassium bromide

0.5% aqueous solution of 1-phenyl-5-mercaptotetrazole

Sodium thiosulfate anhydrous water

The above composition was imidazole or 2-methylimidazole added in an amount of 50 g. The effect achieved in this way on the photographic properties is shown in FIG. 1. Therein mean:

A no addition ■

B imidazole addition - '-

C 2-methylimidazole addition.

As can be seen from Fig. 1, provide the invention Developer (curves B and C) a higher contrast and a good foot clipping effect (cutting off the foot part of the curve) and consequently do not lead to fringing.

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Example 2

The procedure of Example 1 was repeated, this time using the following developers and imidazole compounds
became:

Composition of the developer:

1-phenyl-3-pyrazolidone 1.5 g

Hydroquinone

Anhydrous sodium sulfite sodium hydroxide Potassium bromide

1-Pheny1-5-mercaptotetrazo1 (0.5% aqueous solution) Anhydrous sodium thiosulphate Imidazo! Connection

water

D imidazoI

E · 2-methyl! ImidazoI

F 1-Methy I imidazo I G 2-Ethyl-4-methylimidazole H 2,4-dimethylimidazole I no additive

The results obtained are shown in FIG. As can be seen from this Fig. 2, performed the invention Developer (curves D - H) for a good foot cut-off effect and consequently no fringing. Also, the sensitivity was increased increased (curves D-F and H).

10 g. G 80 G G 14th G G 1 G G 2 ecm G 10 G in the following
amount ad 1 liter 50 50 10 10 10

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2315753

Example 3

The procedure of Example 1 was repeated, but this time the following developers were used:

Composition of the developer:

1-phenyl-3-pyrazolidone 20 g

Hydroquinone 20 g

Anhydrous sodium sulfite 60 g

Sodium hydroxide 20 g

Potassium bromide Ig

Sodium thiosulphate anhydrous 15 g

Imidazole in the following indicated

amount

Water ad 1 liter

Amount of imidazole added (g / l) s -

K 30th L. 40 M. 60 N 70 0 no addition.

The results obtained are shown in FIG. 3. As can be seen from this FIG. 3, the invention provide Developers (Y - N) have a good foot clipping effect and high contrast and consequently do not lead to fringing.

The invention has been above, _s explained in more detail with reference to preferred embodiments but it is clear to the skilled man that these can be modified in many ways and modified without departing from the scope of the present invention.

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Claims (24)

2315753 Claims Ai developer composition for developing high-contrast. Photographic diffusion transfer materials, characterized in that they contain one or more imidazo compounds of the general formula: in which R, a hydrogen atom, an alkyl group, a substituted alkyl group, a vinyl group or an allyl group, R "represents a hydrogen atom, an alkyl group or a substituted one Alkyl group, R ~ a hydrogen atom or an alkyl group and R. a hydrogen atom, an alkyl group or a substituted alkyl group. 2. Developer composition according to claim 1, characterized in that that they have one or more Imidazo! compounds in a lot. of at least about 1 gram per liter of developer composition and has an alkaline pH. 3. Developer composition according to claim 2, characterized in that that they contain one or more Imidazo! compounds in an amount of contains from about 1 to about 250 grams per liter of developer composition. 4. Developer composition according to claim 3, characterized in that that they contain one or more Imidazo! compounds in an amount of 309841/1087 contains about 1 to about 100 grams per liter of developer composition. 5. Developer composition according to claim 4, characterized in that that they contain one or more imidazo compounds in an amount of about 5 to about. Contains 70 g per liter of developer composition. 6. developer composition according to claim 2, characterized in that that it has a pH of 9.5 to 13.0. 7. Developer composition according to at least one of claims 1 to 6, characterized in that they also have one or more Silver halide developing compounds and one or more silver halide solvents contains. 8. Developer composition according to claim 7, characterized in that that it is a pyrazolidone compound as developer compound (1) or an aminophenol compound and- (2) a polyhydroxybenzene contains. 9. developer composition according to claim 8, characterized in that that as 3-pyrazolidone they are a compound from the group 1-phenyl-3-pyrazolidone, l-p-tolyi-3-pyrazolidone, l-phenyl-4-methyl-3-pyrazolidone, l-phenyl-4,4-dimethyl-3-pyrazolidone and 1-p-chlorophenyl-3-pyrazolidone, as aminophenol a compound from the group N-Methy1-p-aminophenol, ρ-aminophenol, 2,4-diaminonphenol, p-benzylaminophenol, 2-methyl-p-aminophenol and 2-hydroxymethyl-p-aminophenol and as polyhydroxybenzene, a compound of the Group hydroquinone, pyrocatechol, chlorohydroquinone, pyrogallol, 309841/1007 Bromohydroquinone, isopropylhydroquinone, toluhydroquinone, methylhydroquinone, 2,3-dichlorohydroquinone, 2,5-dimethylhydroquinone and 2,3-dibromohydroquinone. 10. Developer composition according to claim l, characterized in that that it contains at least one substituted imidazole, the I-substituent making the imidazole water-soluble or alkali-soluble. 11. Developer composition according to claim 10, characterized in that that it contains at least one alkyl substituted imidazole in which any alkyl group has 1 to 12 carbon atoms having. 12. Developer composition according to claim 11, characterized in that that it contains at least one alkyl-substituted imidazole in which any alkyl group is hydroxy, carboxy, acyl or is aryl substituted. 13. Silver salt photographic diffusion transfer development process, characterized in that one or more imidazo! compounds of the ones given below are used general formula produces positive images: R. in which mean: R., a hydrogen atom, an alkyl group, a substituted alkyl group, a vinyl group or an allyl group, R "is a hydrogen atom, an alkyl group or a sub- 3098-41 / 1087 substituted alkyl group, R- is a hydrogen atom or an alkyl group and R, a hydrogen atom, an alkyl group or a substituted alkyl group. 14. The method according to claim 13, characterized in that one Developer composition used "the one or more imidazo! Compounds in an amount of at least about Ig contains per liter of developer composition and has an alkaline pH. 15. The method according to claim 14, characterized in that one Developer composition used that contains one or more imidazo Contains compounds in an amount of from about 1 to about 250 grams per liter of developer composition. 16. The method according to claim 15, characterized in that one Developer composition uses one or more imidazo Compounds in an amount of about 100 grams per ibis Liters of developer composition. 17. The method according to claim 16, characterized in that one A developer composition is used which includes one or more imidazo compounds in an amount of from about 5 to about 70 grams per liter Contains developer composition. 18. The method according to claim 14, characterized in that one Developer composition used that has a pH of 9.5 to 13.0. 19. The method according to at least one of claims 13 to 18, characterized 309841/1087 ^: characterized in that a developer composition is used which also contain one or more silver halide developing agent compounds and contains one or more silver halide solvents. 20. The method according to claim 19, characterized in that one The developer composition used contains, as the developer compound, (1) a pyrazolidone compound or an aminophenol, and (2) a Contains polyhydroxybenzene. 21. The method according to claim 20, characterized in that one Developer composition used as 3-pyrazolidone one Compound from the group l ~ phenyl ~ 3-pyrazolidone, l-p-tolyl-3-pyrazolidone, 1-phenyl- ^ methyl-S-pyrazolidone, 1-phenyl-4j4-dimethyl-3-pyrazolidone and l-p-chlorophenyl-3 ~ pyrazolidone, as aminophenol a compound from the group N-methyl-p-aminophenol, p-aminophenol, 2,4-diaminophenol, p-benzylaminophenol, 2-methylp-aminophenol, 2,4-diaminophenol, p-benzylaminophenol, 2-methyl-p-aminophenol and 2-hydroxymethyl-p-aminophenol and as polyhydroxybenzene a compound from the group hydroquinone, pyrocatechol, chlorohydroquinone, pyrogallol, bromohydroquinone, isopropy! hydroquinone, Toluhydroquinone, Methy! Hydroquinone, 2,3-dichlorohydroquinone, 2,5-dimethylhydroquinone and 2,3-dibromohydroquinone contains. 22. The method according to claim 13, characterized in that one Developer composition used which contains at least one substituted imidazole in which any substituent is the imidazo! water-soluble or alkali-soluble. 23. The method according to claim 22, characterized in that one 309841/1087 Developer composition used, the at least one alkyl · contains substituted imidazo1, in which any alkylsubsti tuent has 1 to 12 carbon atoms. 24. The method according to claim 23, characterized in that one a developer composition is used which contains at least one alkyl-substituted imidazole in which any alkyl group is hydroxy, carboxy, acyl or aryl substituted. 309841/1087 Blank page