DE1945408A1 - Process for making photographic images - Google Patents

Description

Process for making photographic images

The invention relates to a method for producing photographic images by exposing and developing a direct positive, high-contrast photographic recording material, consisting of a layer support and at least one direct positive silver halide emulsion layer, the silver halide of which is at least 50 mol% Chloride is formed by development with a photographic developer, the developer compound of which consists at least for the most part of a polyhydroxybenzene.

In the field of repro technology it is common to produce photographic reproductions of line and halftone originals, to use photographic recording materials with a silver halide emulsion layer which provide extreme contrast having. In general, recording materials with silver chlorobromide emulsion layers are used, the silver chloride content of which is at least about 50 mol-1. After exposure of the recording material against either a halftone negative or an original through a vacuum contact screen the recording material is in a photographic polyhydroxybenzene developer with a very low content of

109820/1730

developed free sulfite. It is believed that the development runs catalytically »Such a development in the field of repro technology is often referred to as a so-called" infectious development " designated.

To control the amount of free sulfite in the developer it has It has been found common to use compounds such as, for example, sodium formaldehyde bisilfit in the developer, which release small amounts of sulfite, which stabilizes the developer solutions at least partially for a short period of time will.

When reproducing halftone originals, it is common to begin with to produce a halftone intermediate photographic image, usually a film negative, in which the tone gradation is seen through shift size of dots of uniform density yields. The shape, density and uniformity of the halftone dots is in place in close relation to the quality of the images to be produced.

For the production of halftone and line images on photographic In ways starting from photographic film recording materials, it is important that a recording material be used that has an extremely high contrast and leads to sharp images.

The disadvantage of the previously known recording materials for repro technology, i. H. the so-called lithographic film recording material is that they are all so-called negative working © recording materials. This is how it is when used of the known recording materials necessary to use a negative material in the camera, from the negative Copy a transparent slide and prepare the printing form from the transparent slide.

109820/1736

.1 9 A 5 A O 8

The object of the invention is to provide a method for producing photographic images by exposure and development of a direct positive, high-contrast photographic: to indicate recording material in which a direct positive, high-contrast recording material with projection sensitivity is used so that when used in a camera, direct positive halftone productions are obtained that can be processed directly for the production of printing forms or printing plates »

The invention was based on the knowledge that the object set can be achieved by using a recording material is used, the silver halide emulsion layer of which has certain silver halide grains.

The invention relates to a process for producing photographic images by exposure and development of a direct positive, high-contrast photographic recording material, consisting of a layer support and at least one direct positive silver halide emulsion layer, the silver halide of which is at least 50 mol% As a result of development with a photographic developer, chloride consists at least predominantly of its developer compound Part consists of a polyhydroxybenzene, which is characterized in that a recording material with at least one silver halide emulsion layer, the silver halide grains of which are internal, the deposition of Centers promoting photolytic silver as well as outer areas with veiled silver halide that is not exposed is developable to silver.

The invention thus ensures that the previously customary process for the production of printing forms accordingly is simplified by using a direct positive recording material of camera sensitivity.

10 9820/1736

Another particular advantage of the invention is that the recording material is exposed to blue light can. This means that it is no longer necessary, as was previously the case, to use the recording material To expose filters and certain light sources, d. H. it is no longer necessary, as before, the recording material to expose certain selected areas of the spectrum with light.

Thus, when performing the method of the invention, it becomes a. Recording material of the type described imagewise exposed to light * the blue region of the visible spectrum and developed with a polyhydroxybenzene developers, so obtained reverse images of excellent quality.

According to an advantageous embodiment of the method of In the invention, a developer is used that has a low concentration contains sulfite ions, which enables so-called infectious development.

According to a further, particularly advantageous embodiment The method of the invention uses a recording material having a direct positive emulsion layer, whose veiled silver halide grains a "halogen conductor connection" adsorbed, which is characterized by a polarographic anodic half-wave potential of less than 0.85 and a half-wave polarographic cathodic potential that is more negative than -1.0.

The term “halogen ^{conductor connection 11} ” here means a so-called “positive hole conductor”, ie a positive vacancy conductor. Reference is made, for example, to the book by Jasprzebski “Nature and Properties of Engineering Materials”, Verlag Wiley and Sons, (1959) page 328, as well the book of

- 4a 109820/1736

MR Wehr and JA Richards "Physics of the Atom", publisher
Addison Wesley, 221.

Recording materials of this type are characterized by an unusually high photographic sensitivity, which is not achieved when halogen conductor compounds are used which do not have the specified polarographic speed
Half-wave potentials are marked.

109820/1736

According to a further particularly advantageous embodiment The method of the invention uses a recording material having a silver halide emulsion layer Electron acceptor compound and a halogen conductor compound contains. By using a combination of a tin electron acceptor compound and a halogen conductor compound, there is a further improvement in photographic properties, for example the sensitivity.

According to a further embodiment of the method of the inventions dung k, a recording material used, the addition

to a halogen conductor compound contains a high molecular weight organic compound, in particular a sulfo compound, as a result of which a particularly high increase in photographic sensitivity can also be achieved.

The method of the invention thus enables the production of photographic images from direct positive, high contrast photographic recording materials of relatively high photographic speed, high contrast and Blue sensitivity.

To carry out the method of the invention, photographic ) graphic developers can be used whose silver halide developments

ler connection at least for the most part, z. B. practical composed entirely of a polyhydroxybenzene compound Typical ones suitable for carrying out the process of the invention Polyhydroxybenzene compounds are hydroquinone, pyrocatechol, Pyrogallol, Isopropy! Hydroquinone, Methy! Hydroquinone, 2,5-dimethylhydroquinone, o-chlorohydroquinone, o-bromohydroquinone, 4-phenylpyrocatechol, 4-phenethylpyrocatechol, 4-phenylpyrocatechol, 4-t-butylpyrocatechol, 4-n-butylpyrogallol and 4,5-dibromo-catechol.

109820/1730

Esters of such compounds are also suitable for carrying out the process of the invention, e.g. B. the formates and Acetates.

The developer compound can be in the recording material itself in the form of a solution or else in a layer on a special Layer carrier are brought to the application.

According to a particularly advantageous embodiment of the method According to the invention, a developer is used whose developer compound is completely or practically completely consists of a 1,4-dihydroxybenzene compound,

The developing agent can be used in various concentrations. As has been expedient. it turned out To use developers containing from about 12 to about 20 grams of developer compound per liter of developer.

The developer can also contain the usual known additives, for example antioxidants, e.g. B. sodium sulfite, alkaline compounds to produce a pH of at least about 9.0, e.g. B. sodium carbonate or sodium hydroxide, Retarders, e.g. B. potassium bromide or sodium bromide, complexing agents and the like.

If necessary, it may be advantageous to use a developer which is a carbonyl bisulfite amine condensation product contains, the developer advantageously having an excess of at least about 0.075 moles of free amine per Liter of developer and a dihydroxybenzene developing agent. Such developers are, for example, from Belgian patent specification 704 595 known.

109820/1736

According to a particularly advantageous embodiment of the method According to the invention, a developer is used which contains:

1 «sodium formaldehyde bisulfite or a carbonyl bisulfite amine condensation product and

2. is about 0.01 to about 0.05 molar in sulfite ions.

Generally such a developer has a pH of at least 9.0. The sodium formaldehyde bisulfite can advantageously be used in concentrations of from about 40 to about 80 grams per liter. Preferably it will be with. an alkali metal sulfite is used. It can also testifies in situ ER * by a mixture of formaldehyde or paraformaldehyde and sodium sulfite is used in the developer.

According to a further advantageous embodiment of the method According to the invention, the process is carried out in the presence of an alkylene oxide ./ "Type is before, for carrying out the process Alkylene oxides suitable for the invention are polyethylene glycol; Polyethylene glycol oleyl ether; Polyethylene glycol cetyl ether; Polyethylene oxide derivatives; Block copolymers, for example those made from blocks of polyoxypropylene and Polyoxyethylene and the like exist, water-soluble organosilicon polyalkylene oxide polymers and the same.

The use is essential for the method of the invention of a recording material having a silver halide emulsion layer with silver halide grains having centers that facilitate the deposition or deposition of photolytic Silver promote and outer districts or an outer shell with or from veiled or spontaneously developable Have silver halide. Typical of such silver halide grains with such a veiled envelope or veiled areas that it is without further exposure . can evolve to silver compared to light »

You can e.g. B. be present in the developer and / or the silver halide emulsion layer.

109820/1736

- yes "

According to a particularly advantageous embodiment of the method According to the invention, a recording material having a silver halide emulsion layer is used, the silver halide grains thereof have a central core made of a silver halide containing centers which the precipitation or Promote or promote deposition of photolytic silver and also have an outer shell or cover around the Core to beings that consist of veiled or spontaneously developable Silver halide. The core emulsion or the cores of the silver halide grains can be chemical or physical have been treated by known methods in order to create the centers which support the deposition or precipitation favor of photolytic silver. The cores can then be enveloped or covered with veiled silver halide will.

According to a further particularly advantageous embodiment The method of the invention uses a recording material having a silver halide emulsion layer, whose Silver halide grains have centers which favor the deposition or precipitation of photolytic silver or promote and are either small enough or deep enough in the crystal so that they can begin to develop are inaccessible. The nuclei also have outer regions or an outer shell of veiled silver halide, which can be developed into silver without exposure.

Centers promoting the deposition or precipitation of photolytic Promoting silver can be produced by various known methods. It has proven to be particularly advantageous proven to generate the centers chemical sensitization processes to use, as for example in the journal "Science et Industries Photographiques", Volume XXVIII, January 1957, pages 57-65. Such chemical sensitization processes fall into three main classes divide, namely a sensitization through GoId-

109820/1736

to

or precious metal compounds, a sensitization means Sulfur compounds, for example with sulfur compounds having a labile sulfur atom and being sensitized by a reducing agent, e.g. B. the treatment of silver halide des with a strongly reducing compound, which introduces small spots of metallic silver into the silver halide grain or crystal.

If the emulsion is chemically sensitized, it is preferably sensitized in such a way that it can be tested by conventional photographic test methods by applying a portion of the emulsion to a conventional transparent support, exposing the recording material to a light intensity scale for 0.01 to 1 second and developing 6 minutes at 2O ⁰ C in a developer of the composition a given later, a sensitivity has long, which is greater (measured at a density of 0.1 above fog) than the sensitivity of an identical test sample of the same emulsion which is exposed in the same manner which was developed in the following composition given, however, 5-minutes, bleached in an aqueous solution of 0.3 $ Kaliumferricyanidlösungwn 18 ⁰ C and 5 minutes at 18 ° C in a developer B.

The developer A is a conventional surface developer and the developer B is a so-called surface developer. internal developer with strong silver halide solvent activity.

Developer A 2.5 G N-methyl-p-aminophenol sulfate 10.0 G Ascorbic acid 35.0 G Kaliuametaborate 1.0 G Potassium bromide 1.0 liter topped up with water * u £ 9.6 PH value "

109820/1736

Developer B

N-methyl-p-aminophenol sulfate 2.0 g

Sodium sulfite, dehydrated 90.0 g

Hydroquinone 8.0 g

Sodium carbonate, monohydrate 52.5 g

Potassium bromide 5.0 g

Sodium thiosulfate 10.0 g

made up to 1.0 liter with water

The emulsions can be used in a wide variety of ways for the stated purpose known methods are sensitized. For example, the emulsions can be naturally active Gelatine can be digested or sulfur compounds can be added, for example sulfur compounds from U.S. Patents 1,574,944; 1 623 499 and 2 410 689 of known type.

The emulsions can also chemically, for example, with gold salts of the US Pat. Nos. 2,399,083 and 2 642 361 known type are sensitized »Typical suitable gold salts are, for example, potassium chloroaurite, Potassium aurithiocyanate, potassium chloroaurate, auritrichloride and 2-aurosulfobenzothiazole methochloride.

The emulsions can also be chemically combined with reducing agents such as stannous salts according to the USA patent 2,487,850, polyamines, e.g., diethylenetriamine, according to U.S. Patent 2,518,698; polyamines, e.g. B. Spermin, according to USA patent specification 2,521,925 or bis (ß-aminoethyl) sulfide or its water-soluble salts, according to USA patent specification 2 521 926 should be sensitized *

109820/1736

Finally, the emulsions can be used during or after the formation of the silver halide with salts of polyvalent metals be treated, for example with salts of bismuth, the • noble metals and / or with salts of metals of group VIII des periodic table of elements, e.g. B. ruthenium, rhodium, palladium, iridium, osmium and platinum. Typical ones suitable for this Compounds are, for example, ammonium chloropallate, potassium chloroplatinate, sodium chloropalladite and the like.

For the creation of centers, which the precipitation or deposition The emulsions can further promote or promote the formation of photolytic silver by exposure to light either low or high intensity are obscured before the outer domes or the outer shell on the silver halide grains is applied.

The silver halide emulsion layers of the The recording material used in the method of the invention can furthermore contain conventional spectral sensitizers contain, such as cyanines, merocyanines, complex trinuclear cyanines, complex trinuclear merocyanines, styryl dyes and hemicyanines. Particularly advantageous spectral sensitizers have found merocyanines from the U.S. Patents 2,493,747 and 2,493,748 of the known type For example, merocyanines substituted by arboxyl groups, merocyanines substituted by sulfo groups and Rhodanine merocyanine dyes

The silver halide grains of the emulsion can be used to achieve inner centers that promote or favor the deposition of photolytic silver, according to various methods be sensitized.

1098 2 0/1736

One method is to add the sensitizer to the medium in which the silver halide crystals form occurs before precipitation of the silver halide crystals or immediately after the silver halide crystal formation has begun. The concentration of the sensitizer is considerably reduced by inclusion of the agent in the silver halide grains, so that if the precipitation continues, the amount of centers which the deposition or favor precipitation of photolytic silver, decreases in the outer regions of each grain.

It has proven to be advantageous to generate sufficiently narrow centers that facilitate the deposition of photolytisehern Promote silver so that they are not developable and do not produce visible images after exposure which are necessary in order to obtain good reversal images with the emulsions.

When the emulsion layer is in an internal developer, the direct positive emulsion layer of a recording material used in practicing the process of the invention can be reversed by exposure to blue light twice the normal exposure time without a substantial increase in the i _{n values of the image recording} developer B type is developed.

The silver halide grains of the silver halide emulsion layer used in practicing the method of the invention Recording material can also be advantageous according to another Embodiment Cores made from a coarse-grained silver halo genid, on which silver halide is formed from a finer-grained silver salt through Ostwald ripening the shell has failed. Furthermore, coarse-grained silver halides can be used to produce the shell over finer-grained ones Cores are used if the SiI-

109820/1736

Berhalide is more soluble in water than the silver halide which forms the nuclei. Furthermore, it is also possible to use the silver halide shell or to produce the outer regions immediately after the formation of the nuclei without interrupting the precipitation.

It has been found to be advantageous to structure the silver halide grains in such a way that one molar equivalent nucleus is superhalide about 2 to 8 molar equivalents of shell or shell silver halide are omitted. The shell or shell or the outer Thus, regions of the silver halide grains have sufficient strength to allow developer to be applied during the Prevent development of the emulsion layer towards the core.

The shells or outer regions of the silver halide grains are fogged so that they can be made using conventional surface developers can be developed into metallic silver. Practically all of the silver halide grains are thereby before the Exposure of the emulsion layer and / or its development obscures, d. H. the emulsion layers are uniformly fogged. The obfuscation can be due to chemical sensitization caused against fog with sensitizers be like them for chemical sensitization of the Core emulsion, high intensity light and other known shifting techniques.

While the cores of the emulsion are not sensitized to haze need to be, the shell or the outer areas of the silver halide cores are obscured, for example by a reduction masking with a reducing acting compound, for example stannous chloride. The obfuscation can further be carried out, for example, with a reduction sensitizer, a noble metal salt, e.g. a gold salt, and a reduction sensitizer due to a high pH value and low ρAg values in the SiI overhalide precipitation and the like.

d. H. a reducing compound

109820/1736

The silver halide grains are advantageously so heavily fogged that a density of at least 0.5 is achieved when the emulsion layer is developed without being exposed for 5 minutes in a developer of the type of developer A, if a direct-positive emulsion layer with the grains in a layer thickness of about 50 to about 1000 mg silver per 0.09 m ² (1 sq.ft.) has been applied to a substrate.

The emulsions used to produce the recording material preferably have grains of a practically uniform grain size distribution, in contrast to conventional emulsions, which are characterized by a broad grain size distribution. Emulsions whose silver halide grains are characterized by an average grain size of about 0.05 to 10 microns in diameter have proven particularly advantageous in the context of the invention Silver, preferably 200 to about 600 mg of silver, are used on a support area of 0.09 m ² (1 sq.ft.).

Preferably, the silver halide of the silver halide emulsion layer consists of at least 70 mol of chloride. Advantageously, the silver halide consists of at least 70 mols of chloride and less than 5 mols of iodide and the remainder of bromide. The silver halide grains of the silver halide emulsion layer can, for example, also consist entirely of chloride. Emulsionaschichten / of this type provide for an exposure in a sensitometer and 2 minutes long been developing in a developer having the composition shown below at 20 ⁰ C a γ-value of at least 4, measured at a density of JO, 3 and 3.0.

/ ~ according to deτ invention and specifically

109820/1736

1945A08

- J * - 500 ml U 30.0 G Water, about 3O ⁰ C 7.5 G Sodium sulfite, dehydrated 2.2 G Paraformaldehyde 7.5 G Sodium bisulfite 22.5 G Boric acid, crystalline 1.6 G Hydroquinone 1 * 0 liter Potassium bromide topped up with water pH = 10.1

According to an advantageous embodiment of the method of "The invention relates to recording materials with silver halide emulsion layers whose fogged silver halide grains contain a halogen conductor compound adsorbed.

The use of such halogen conductor connections has proven to be particularly advantageous proved, which have certain polarographic half-wave potentials, d. H. certain on polarographic Ways determined oxidation-reduction potentials.

The determination of the polarographic half-wave potentials can take place according to methods such as are known, for example, from the book "New Instrumental Methods in Electrochemistry", . by Delahay, Interscience Publishers, New Yorki New York, 1954; the book "Polyragraphy" by Kolthoff and Lingane, 2 »edition, Interscience Publishers, New York, New York, 1952; the journal "Analytical Chemistry", 36 (1964), page 2426 and the journal "Analytical Chemistry", J50 (1958), p 1576.

The cathodic measurements can be performed with a 1 χ 10 molar Solution of the halogen conductor compound in a solvent, for example methanol, take place, which is 0.05 molar with respect to Lithium chloride is, using a dripping

109820/1736

Mercury electrode, where the polarographic half-wave potential the most positive cathodic stage with E,, denoted will.

-4 The anodic measurements can be carried out with a 1 χ 10 molar aqueous solvent solution, for example methanolic solutions of the halogen conductor compound, which is 0.05 molar in sodium acetate and 0.005 molar in acetic acid, using an electrode a carbon paste or pyrolytic graphite, the voltemetric Half-wave potential of the most negative anodic rendering with E-. -j is called.

An aqueous silver-silver chloride (saturated potassium chloride) electrode at 20 ^° C. can be used as a comparison electrode for the measurements.

Halogen conductor connections particularly suitable according to the invention, which can be organic or inorganic in nature have polarographic anodic half-wave potentials E, ·. of less than 0.85 and polarographic cathodic half-wave potentials Ef% that are more negative than -1 »0, where the potentials were determined according to the guidelines of the IUPAG agreement.

Particularly advantageous halogen conductor connections have an anodic half-wave potential of less than 0.62 and a cathodic half-wave potential that is more negative than -1.3.

Advantageous halogen conductor connections which can be used in the context of the method of the invention are the spectral ones merocyanine sensitizing dyes of the following general ones Structural formula:

B Cae (L — L) - C \ \ , ' ^K '

109820/1736 * "* '

1345408

fi

where mean:

A the to complete a sour hetero

cyclic nucleus required atoms, d. H. for example those necessary to complete a rhodanine or 2-thiohydantdinkernes Atoms;

B to complete a basic, stick

substance-containing heterocyclic core required Atoms, d. H. for example the

W atoms necessary to complete a benzo

tiazole, naphthothiazole or benzoxazole nucleus required are;

L is a methine residue, d. H. a possibly substi

tuted methine radical, for example a methine radical substituted by an alkyl or aryl radical, z. B a methine residue of the following formulas:

-CH =, -C = or -C = _and

> CH ₇ C ^ -H ₁ .

ο if

η = 0, 1 or 2.

Typical merocyanine dyes suitable according to the invention given formula are for example:

S-carboxymethyl-S - ^ 'CS-ethyl-E-benzothiazolinylidene) ethylidene-rhodanine;

3-ethyl-5 - ^ "i-C4-sulfobutyl) -4 (1H) -pyridyliden7rhodanine, . Sodium salt;

3-carboxymethyl-5- ^ ~ (3-ethyl-2-benzoxazolinylidene) ethylidene-7-2-thio-2,4-oxazolidinedione;

109820/1736

If

1 -Carboxymetiiyl-5 - ^ "(3-ethyl-2-benzothiazolinylidene) ethylidene-7-3-phenyl-3-thiohydantoin;

AI " (1-ethylnaphtho ^ '1,2-d7thiazolin-2-ylidene) -1 methylethylidene7-3-methyl-1- (4-sulfophenyl) -2-pyrazolin-5-one and

4 - ^ "(3-ethyl-6-nitro-2-benzothiazolinylidene) ethylidene7 · S-phenyl-Z-isoxazolin-S-one.

Further halogen conductor compounds suitable for carrying out the method of the invention can be found, for example, in US Pat Belgian patent 695 361 known. Process for the preparation of the merocyanine dyes are, for example, from the U.S. Patents 2,493,747 and 2,493,748 are known.

The halogen conductor compounds can be in various concentrations It has been found to be useful to use them in concentrations of about 25 mg to about 2.0 g per Moles of silver to use. Concentrations of about 150 to about 1000 mg per mole of silver are preferably used »

Advantageously, the halogen conductor compounds can be used in combination with high molecular weight organic compounds, i. SuIfo connections, are used, which creates another Can achieve an increase in the photographic sensitivity of the direct positive emulsions. Sulfonated polynuclear ones are suitable aromatic compounds with at least one sulfo group. The term "polynuclear aromatic compounds" means that the compounds should have two or more benzene rings fused to one another, as is the case, for example is the case with naphthalene or pyrene. The expression

109820/1736

However, "polynuclear aromatic compounds" also include Compounds that have at least two benzene rings or other aromatic rings bonded directly to one another . are, examples of which are diphenyl, terphenyl and quaterphenyl. Furthermore, the benzene or aromatic Rings can also be linked to one another by an aliphatic bond.

Such compounds containing at least one sulfo group can be represented by the following general formula:

\ R - SO ₃ M

wherein R is a polynuclear aromatic group as indicated and M is a cation such as hydrogen or one which brings about the water solubility of the compound Cation, for example a sodium, potassium, ammonium, triethylammonium, triethanolammonium or pyridinium cation.

Typical sulfo compounds that can be used are:

Bis (s-triazin-2-ylamino) stilbene-2,2'-disulfonic acid, sodium salt (for example, commercially available under \ the names Calcofluor White MR and Leucophor B);

Sodium 6- (4-methoxy-S «sulfo-ω-phenylacryloy1) pyrene

3,4-bis (4-methoxy-3-sulfobenzamido) dibenzo-thiophenedioxide, sodium salt;

4 ', 4 "-bis (2,4-dimethoxy-5-sulfobenzamido) -p-terphenyl, Disodium salt;

Chrysene-6-sulfonic acid, sodium salt and '

109820/1736

4,4 ^l -Bis ^ "2-phenoxy-4- (2-hydroxyethylamino) -1,3,5-triazin-6-ylamino7s tuben-2,2'-disulfonic acid, disodium salt.

The SuIfοverbindungen can be in different concentrations can be applied. It has proven to be advantageous to use these compounds in concentrations of about 0.02 to about 10 g to be used per mole of silver halide »

It has also proven advantageous to use the halogen conductor connections to be used together in combination with a water-soluble halide salt, for example a bromide salt, as indicated in Belgian patent 695,363, for example.

According to a particularly advantageous embodiment of the method According to the invention, a recording material is used which comprises a halogen conductor compound and an electron acceptor contains. By using this combination of compounds, particularly advantageous sensitivities can be achieved.

Electron acceptors suitable for carrying out the method of the invention are so-called. Photoelectron acceptors or desensitizing dyes, their use in photographic Reversing systems is known. Compounds of this type are, for example, those from the Belgian patent 695,364 known desensitizers that trap electrons

The electron acceptors can also be in different concentrations can be applied. Preferably they are used in concentrations of from about 100 mg to about 2 g per mole of silver halide used · Particularly suitable electron acceptors include azoles substituted by nitro residues and nitro residues substituted cyanines and merocyanine dyes, including

109820/1736

borrowed indolocarbocyanine dyes, phenosafranine, pinacryptol yellow and the same.

The silver halide emulsion layers for carrying out the Recording materials used in the process of the invention can furthermore contain the customary, known emulsion additives contain, for example gelatine plasticizers, coating auxiliaries, Antifoggants, e.g. B. azaindines and hardeners, such as aldehyde hardeners, e.g. formaldehyde, mucochloric acid, glutaraldehyde bis (sodium bisulfite), Maleic acid dialdehyde, aziridines, dioxane derivatives and oxypolysaccharides.

The customary known ones can be used to produce the emulsion layers hydrophilic, water-permeable binder is used e.g. gelatin, colloidal albumin, polyvinyl compounds, Cellulose derivatives, acrylamide polymers and like that. Mixtures of these binders can also be used. Finally, the binders can too contain dispersed polymerized vinyl compounds, as they are, for example, from US Patents 3,142,568, 3,193,386, 3,062,674 and 3,220,884 are known. These include, for example, the water-insoluble polymers of Alkyl acrylates and alkyl methacrylates, acrylic acid, sulfoalkyl acrylates or sulfomethacrylates

The support of the recording material used in the context of the invention can consist of one of the usual known layer supports, for example a cellulose nitrate film, a cellulose ester film, a polyvinyl acetal film, a polystyrene film, a polyester film, e.g. B. one Foil made of polyethylene terephthalate and the like. Or else made of glass, paper and metal. Layer supports made of paper, which with a layer of a os-01efinpolymeren are coated, in particular polymers of

109820/1736

- ΊΑ -

JU

o-olefins having 2 or more carbon atoms, for example Polyethylene, polypropylene, ethylene-butene copolymers and the like.

It has proven to be particularly advantageous to develop the exposed recording material continuously Carry out developing device, as they are known, for example, from US Patents 3,025,779, 3,078,024, 3,122,086, 3,149,551, 3,156,173 and 3,224,356.

In such continuous development devices the recording material is continuously fed into and out of at least one developer solution. As special The roller transport developing devices have proven advantageous which are known from US Pat. No. 3,025.

The recording materials may optionally contain certain onium salts, e.g. B. quaternary ammonium salts, sulfonium salts and phosphonium salts, which increase the speed of development without adversely affecting the contrast can be. Suitable for carrying out the method of the invention On tin compounds are for example from the USA patents 2,271,623, 2,944,898, 2,944,900, 2,288,226, 2,275,727, 2,271,622 and 2,886,437 and the British patent 1 067 958 known. The onium compounds can, for example used in concentrations of from about 0.01 to about 2.0 grams of onium salt per mole of silver in the silver halide emulsion layers will.

The development speed of the recording materials can also be increased in an advantageous manner in that of the emulsion layer about 0.005 to about 2.0 grams of a 3-pyrazolidone can be added per mole of silver. Such pyrazolidones are known, for example, from US Pat. No. 2,751,297.

109820/1736

19A5408

They can be represented by the following general structural formula:

0 - C

Χ — Ν

CHR ₁

Herein mean:

- and R ₃

a hydrogen atom or an acetyl group;

a heterocyclic group or an aryl group the benzene or naphthalene series and

a hydrogen atom, an alkyl or aryl group the benzene or naphthalene series and

one atom of water or one AIk) I group.

Typical suitable 3-pyrazolidones of this type are 1-phenyl-3-pyrazolidone; 5-methyl-3-pyrazolidone; i-phenyl-S-phenyl-3-pyrazolidone; i-phenyl-S-methyl-3-pyrazolidone; 1-phenyl-4,4-dimethyl-3-pyrazolidone; 1-p-hydroxyphenyl-4,4-dimethyl-3-pyrazolidone and 4-methyl-1-phenyl-3-pyrazolidone.

Optionally, the 3-pyrazolidones can also be used in one layer of the recording material are accommodated to the SiI overhalide emulsion layer of the recording material is adjacent.

10 9 8 2 0/1736

The following examples are intended to illustrate the invention in more detail.

example 1

The following emulsions A, B, C and D were made:

A) Emulsion made by continuous precipitation, fogging with an iridium salt and a reducing agent

A silver chloride emulsion was prepared by simultaneously adding 1 mole of sodium chloride and 1 mole of silver nitrate over a period of 36 minutes at 70 ° C. to a solution containing 10 g of gelatin and 40 mg of potassium chloroiridite. Another 40 g of gelatin were then added, whereupon the emulsion was cooled ^{to 40 ° C.} A further 100 g of a 10% gelatin solution were then added, whereupon the emulsion was quenched and washed with cold water. The washed emulsion was then chemically fogged by adding 2 mg of thiourea dioxide per mol of silver and heating at 65 ^° C. for 30 minutes until a high contrast was obtained and the emulsion could be developed to maximum density without being exposed.

B) Emulsion produced by intermittent precipitation, treatment of the core emulsion with sulfur and gold sensitizers. Reduction concealment

A silver chlorobromide emulsion was prepared by simultaneous addition of 0.225 moles of sodium chloride, 0.25 moles of silver nitrate and 0.025 moles of potassium bromide over a period of 5 minutes at 65 ⁰ C to a / solution containing 10 g of gelatin. Then 1.78 mg of sodium thiosulfate and 1.72 mg of potassium chloroaurate were added and the emulsion was kept for 10 minutes . Finally , within a period of / ~ aqueous

109820/1736

Another 15 minutes at 65 ° C. 0.675 moles of sodium chloride, 0.75 moles of silver nitrate and 0.075 moles of potassium bromide were added. 40 g of gelatin were then added, whereupon the emulsion was quenched and washed. Finally, the emulsion was obscured by heating with 0.75 mg of thiourea dioxide at 65 ^{° C. for 40 minutes.}

C) Emulsion, produced by interrupted precipitation with AgCl cores and an AgClBr shell as well as concealment with a reducing agent and a gold compound

A silver chlorobromide emulsion was prepared by simultaneous addition of 0.25 moles of sodium chloride and 0.25 moles of silver nitrate over a period of 5 minutes at 70 ⁰ C to a / solution containing 25 g of gelatin, within a period of 1 minute were performed at 70 ⁰ C for an additional 0.65 moles of sodium chloride, 0.09 moles of potassium bromide and 74 O ₉ moles of silver nitrate was added. Finally, another 25 g of gelatin was added and the emulsion was quenched and washed. The washed emulsion was then chemically fogged by heating for 20 minutes with 0.3 mg of thiourea dioxide per mole of Ag and addition of 0.2 mg of potassium chloroaurate per mole of silver and heating at 65 ° C. for 50 minutes and further heating until a high level was achieved Contrast and develop the emulsion to maximum density without exposure.

D) Emulsion produced by interrupted precipitation with AgBrJ cores + iridium, AgCl shell precipitation, obscuration with a reducing agent and a gold compound

A Silberchlorobromojodidemulsion was prepared by simultaneous addition of 0.4875 moles of potassium bromide, potassium iodide, 0.0125 moles and 0.50 moles of silver nitrate over a period of 35 minutes at 55 ⁰ C to a / Eösung containing 21 g of gelatin and 52.5 mg Kaliumchloroiridit contained. Then there were more

/ "aqueous

10982071736

19 g of gelatin were added and the emulsion was quenched and washed with cold water. Finally, 61.5 g of gelatin was added again, was melted and the emulsion at 6O ⁰ C. Now 4.5 moles of sodium chloride and 4.5 moles of silver nitrate were added simultaneously over a period of 24 minutes at 60 ° C. A further 50 g of gelatin were then added, whereupon the emulsion was quenched, washed and chemically fogged as in the case of emulsion C.

The emulsions obtained were then using a carboxy methyl · thiazoline rhodanine merocyanine dye from the US patent 2,493,748 of the known type and then applied to cellulose triacetate film support in such a way that the coating thicknesses given in the table below were obtained.

The resulting recording materials were then exposed to and using a developer of the following composition Developed into direct positive images for 3 3/4 minutes.

Water, about 3O ⁰ C 500 ml

Sodium sulfite, dehydrated 30.0 g

Paraformaldehyde 7.5 g

Sodium bisulfite 2.2g

Boric acid, crystalline 7.5 g

Hydroquinone 22.5 g

Potassium bromide 1.6 g

made up to 1.0 liter with water pH = 10.1

In detail, the following results were obtained.

10-98 20/17 36

* ar -

Relative

emulsion Ag uug \ uigf yjfyj? «Ι j
gelatin opportunity D.
Max min A. 106 392 2S7 1 * 21 0 »S2 B. 99 366 447 0 * 9S 0 * 04 C. UU 416 339 0.93 0.32 D. 200 463 1141 U96 0.08

Example 2

The recording files used in the method of the invention are characterized by greatly improved photo * graphic properties in terms of sensitivity, contrast and B- compared to recording materials that have a light-sensitive emulsion layer made of a so-called * Herschel-üm show sweeping emulsion «This is to be shown below» First, the emulsions I and F would be prepared.

Emulsion E.

It was a Hersehe1 reverse emulsion according to that in Example 2 of US Pat. No. 2,541,472 prepared with the exception * that the desensitizing agent is 4-nitro-6-chlorobenzotriazole * The emulsion was then coated on a cellulose acetate film support.

Emulsion F

A SilbeTChloridemulsion was prepared by simultaneous addition of Mt mol of silver nitrate and 2.1 mole of sodium chloride over a period of 20 minutes at 70 ⁰ G to a solution containing 10 g of gelatin. The emulsion was then ^{cooled to 40 °} C., whereupon 50 mg of potassium chloroiridite were added and the emulsion was allowed to stand for 10 minutes. The temperature would then

109820/1736

increased to 7O ⁰ C, followed by one further 1/2 mole of silver nitrate and sodium chloride were added over a period of 20 minutes "The emulsion was then cooled to 40 ⁰ C, after which 70 g of gelatin was added and the emulsion was chill set. It was washed with cold water for 2 hours. The washed emulsion was then obscured by heating at 60 ^° C. for 20 minutes with 0.3 mg thiourea dioxide per mole of silver, adding 0.2 mg of potassium chloroaurate per mole of silver, heating to 65 ^° C. for 50 minutes and continuing heating until this was achieved high contrast and development of the emulsion to maximum density without exposure.

The emulsion was then coated on a cellulose acetate film support applied.

The recording materials obtained were then exposed to a tungsten light source, once with an unmodulated light source Light and once with light modulated by a yellow Wratten No. 4 filter. The exposed recording materials were then developed for 2 minutes in a developer of the composition given in Example 1 The results compiled in the following table were obtained.

Exposure to white light. Exposure to yellow light

n ™ "i _e 4""Relative Relative

Emulsion _{Emp £ in} ^ sens- ""

————— possibility γ max min Ii dike it γ max min

to
E 46 1.98 low 100 9.5 1.96 0.04

F 1910 7.8 2.70 0.16 110 10.3 2.70 0.24

Example 3

This example shows the use of a molar connection,

109820/1736

namely a halogen conductor dye for improving the photographic properties of the recording material.

First, an emulsion G was produced «

Emulsion G

350 mg of the halogen dye 3-carboxymethyl-5 - ^ "3-methyl-2 (3) -thiazolinyiiden} -isopropylidea / rhodanine per mole of SiI- * ber were added to a portion of the emulsion F described in Example 2. The emulsion was applied to a cellulose acetate

film backing applied. ι

Samples of the recording materials with the emulsions F and G were then exposed to white light and in a developer of the composition given in Example 1 for 1 3/4 minutes developed. The following results were obtained.

F. Relative
Sensitivity -JL Max _min emulsion G 100 7.8 2.42 0.20 emulsion 4th 26 900 15 * 5 2.24 0.08 example

This example shows that a so-called lithographic recording material can advantageously be used for developing the exposed recording material Developer can be used with a free Amia.

Samples of those made using Emulsions F and G. Recording materials were exposed to white light and exposed to finally in an amine developer of the following for 1 1/2 minutes Composition developed:

109820/1736

Jl

1943408

Sodium bis (2 ~ hydroxylthyl} amino «

methanesulfonate

Sodium sulfite

Boric acid

Hydroquinone

Potassium bromide

2.2 '-Iminodiethanol made up with water pH value «9.5

82.0 g 3.0 g 7 * S g 22 _t S g

M g 39.0 g 1.0 liter

If necessary, sodium formaldehyde bisilicate and 2 _t 2 · * iminodiethanol can be used to form the compound in situ.

Additional samples of the recording materials were made with light exposed at a wavelength of 365 μ (for illustration the sensitivity inherent in emulsions)> whereupon they 2 1/4 For minutes in the aain desiccator of the specified composition * The results obtained are in compiled in the following table »

White light ¹ w min exposure
at _3fif5..j ». Relative
Sensation
opportunity Ύ 3.0
2.25 0.09
0.08 Relative
Sensation
opportunity Emulsion F
Emulsion G 100
42 700 8.3
9.5 200
33 900

109820/1736

Similar results were obtained when the recording materials exposed to light of other wavelengths ranging from 350 to 500 millimicrons.

Example 5

This example illustrates the use of a recording material with a direct positive emulsion layer containing a halogen conductor compound as well as an electron acceptor contains «First the emulsions H and I were produced.

Emulsion H

200 mg of 3-carboxymethyl-5- £ "(3» metfoyl »2 (3)» thiozolinylidene) isopropylidene-rhodanine were added to one portion of the emulsion F added per mole of silver as a halogen conductor compound »The emulsion was then coated on a cellulose acetate support.

Emulsion I.

100 mg of the electron acceptor were added to a portion of the emulsion H 1,1 '"" Diethyl-Z ^' - cyanine chloride, which with N-bromosuccinimide treated was added per mole of silver. The emulsion was then also coated on a cellulose acetate support applied.

The recording materials were then left for 1 1/2 minutes developed in a developer of the composition given in Example 1. The following results were obtained.

Relative

Sens- "_

opportunity _m j _mm max min

Emulsion H 100 2.90 1.56 0.08

Emulsion I 159 1.88 1.42 0.08

109820/1736

Example 6

This example illustrates the use of another Electron accepting dye. Another emulsion J was prepared.

Emulsion J

200 mg of a phenylimidazoquinoxaline indolocarbocyanine dye were added to a portion of the emulsion H / added as electron acceptor per mole of silver. The emulsion then became again applied to a cellulose acetate support.

Samples of recording media with emulsions H and J were exposed and developed in a developer of the composition given in Example 1 for 3 3/4 minutes. It the following results were obtained.

Relative
Sensation
opportunity Emulsion H 10Ö Emulsion J 91

DD.
max min

2.55 1.21 0.08 3.30 1.41 0.08

The results obtained show that "the recording material with the emulsion J leads to higher ^ _max " ^ eTt9n t, a higher contrast and a sharper sag compared to the recording material with the emulsion H, which contains the halogen ^{acceptor dye alone "}

/ "ie 200 mg of 1,3-diethyl-l ^l -methyl-2 ^l -phenyliraidazo- ^" 4,5-b _- 7quinoxalino-3 ^t -indolocarbocyanin iodide.

109820/1736

Claims (1)

Claims (Iy Method of Making Photographic Images by Exposure and development of a direct positive, high-contrast photographic recording material, consisting of a support and at least one direct positive silver halide emulsion layer, the Silver halide consists of at least 50 mol of chloride » by development with a photographic developer, the developer compound at least predominantly Part consists of a polyhydroxybenzene, characterized in that a recording material used with at least one silver halide emulsion layer, their silver halide grains internal, the deposition PhotoIytic silver mining centers as well outer districts with veiled silver halide, the can be developed into silver without being exposed. 2. The method according to claim 1, characterized in that a recording material with a direct positive silver halide emulsion ion layer is used, the silver halide grains from a central core of silver halide with Centers “which allow the deposition of photoIytic silver favor and an outer shell of veiled silver halide covering the core, which is without exposure more evolved to silver exist. 3 »Process according to claims 1 and 2, characterized in that that a recording material having a silver halide emulsion layer is used, whose silver halide centers which the deposition of photolytic Favor silver, contain, which by chemical treatment 109820/1736 19A5408 JS development of the nuclei were generated » 4. Process according to Claims 1 to 3 »characterized in that a recording material having a silver halide emulsion layer is used, the silver halide grains centers for the deposition of photolytic silver generated by an iridium salt. 5. Process according to Claims 1 to 4 »characterized in that that a recording material with a silver halide emulsion layer is used, the silver halide of which is at least 70 MoI-I consists of chloride. 6. The method according to claims 1 to 5, characterized in that that a recording material with a direct positive emulsion layer is used, the fogged silicon superhalide grains thereof adsorbs a halogen acceptor compound included, which by a polarographic anodic Half-wave potential from less to 0.85 and one polarographic cathodic halftone stem from is labeled more negative than -1.0. 7. The method according to claim 6, characterized in that a recording material is used whose silver halide emulsion layer contains a merocyanine dye as the halogen acceptor compound. 8. The method according to claims 1 to 7, characterized in that a recording material with a direct positive 'Silver halide emulsion layer is used which contains a sulfo compound of the formula: R-SO ₃ M 109820/1736 contains, wherein R is a polynuclear radical and M is a cation represent, '9. Process according to claims 1 to 8, characterized in * that air development of the recording material as a polyhydroxybenzol compound Hydroquinone is used. 10. The method according to claims 1 to 9, characterized in that that a developer is used for development which contains a carbonyl bisulfite amine condensation product * 11. The method according to claim 10, characterized in that a developer is used which contains an excess of free amine. 12. The method according to any one of claims 1 to 11, characterized in that that a recording material is used which contains a 3-pyrazolidone. 13. The method according to claims 1 to 12, characterized in that one for developing the recording material continuous transport developing device used " 14. The method according to claim 13, characterized in that one to develop the recording material continuously working roller transport developing device used" IS * method fiäcn claims 1 to 14, characterized in that that a recording material with a direct-positive blue-sensitive SiI-ber & älogenidemuls ion layer used. 109820/1736 16. The method according to claim 15, characterized in that a recording material with a blue-sensitive direct positive silver halide emulsion layer used, which is a halogen conductor compound with a polarographic anodic half-wave potential of less than 0.85 and a polarographic cathodic half-wave potential ■ © n more negative than -1.0. 17. The method according to claim 15, characterized in that a recording material with a direct positive blue sensitive silver halide emulsion used, which contains an electron acceptor. 109820/17 36