DE1945409A1 - Process for making photographic images - Google Patents

Description

Eastman Kodak Company, 343 State Street, Rochester, New York State, United States of America

Process for making photographic images

The invention relates to a process for producing photographic images by developing an exposed photographic recording material with a blue-sensitive one direct-positive, high-contrast silver halide emulsion layer, the silver halide of which consists of at least 50 mol%, preferably at least 70 mol%, of silver chloride and a direct positive photographic recording material for Implementation of the procedure.

It is known in the field of repro technology for manufacture photographic reproductions of line and halftone images, To use recording materials with silver halide emulsion layers with an ex tie me η contrast. Usually be Recording materials with silver chlorobromide emulsion layers are used, the silver chloride content of which is at least about 50 mol-I. After exposure of the recording material compared to a halftone negative or an original by one Vacuum contact screen, the recording materials are developed in a photographic developer, the developer compound of which consists of a polyhydroxybenzene, the developer

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curlers are characterized by a very low content of free sulfite is. It is believed that the development is catalytic. Often there is development in the field the repro technology referred to as so-called infectious development. To control the level of free sulfite in the developers, it has become common practice to use sodium formaldehyde bisulfite, d. H. a compound that releases small amounts of sulfite, so that the developer solutions at least partially for stabilized for a short period of time.

The disadvantage of the known recording materials, i. H. lithographic films for repro technology is that they are all negative-working. To this day it has been therefore necessary to use negative material in the recording cameras use to make a slide from the negative copy and to use the slide to make the printing plate.

Would it be possible to produce a direct positive, high-contrast To produce recording material with projection sensitivity, this could be done in recording cameras for production direct positive halftone images can be used, which can then be used directly for the production of printing plates * Using direct-positive recording materials of camera sensitivity would therefore be an expensive one Eliminate stage of the previously known process.

It would also be desirable to develop a direct positive Recording material for repro technology, from which image recordings of excellent quality using generate blue light. This would avoid the use of filters and light sources for systems in which can only be exposed to selected areas of the spectrum «

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The object of the invention was therefore to provide a method for production photographic images by developing an exposed photographic recording material having a blue-sensitive direct positive high-contrast silver halide emulsion layer and a recording material for implementation of the procedure.

The subject matter of the invention is based on a method of production photographic images by developing an exposed photographic material with a blue sensitive direct positive high contrast silver halide emulsion layer, their silver halide to at least 50 mol%, preferably at least 70 mol% of silver chloride and in which the recording material is developed with a developer, its silver halide developing agent wholly or almost entirely from a polyhydroxybenzene developer compound consists of and is characterized in that a recording material with a silver halide emulsion layer is used is used which contains an organic electron acceptor and a halogen conductor compound and their silver halide grains are fogged.

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

A so-called "positive hole conductor" is used as a "halogen conductor connection". H. a so-called positive vacancy conductor meant, d. H. a special type of halogen acceptor that does not bind the halogen tightly, but releases it again after it has been absorbed (cf. also the book by Jasprzebski "Nature and Properties of Engineering Materials", Verlag Wiley and Sons, (1959) Page 328).

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When using recording materials, their silver halide emulsion layer It has been found advantageous to contain halogen conductor compound adsorbed on the silver halide grains have been shown to use such halogen conductor compounds which have a polarographic anodic half-wave potential of less than 0.85 and a polarographic cathodic half-wave potential of more negative than -1.0 emulsions, which has both an electron acceptor and a halogen conductor compound of the properties described are through characterized by an unusually high sensitivity.

According to another particularly advantageous embodiment According to the method of the invention, a recording material having a direct positive silver halide emulsion layer with fogged Silver halide grains which consist of at least 50 mol of chloride and an organic electron acceptor used, the silver halide grains of the silver halide

veiled
as are that they are the examinees

after application to a conventional support in the form of a photographic silver halide emulsion to produce a maximum density of at least about 1, after 6 minutes of development at 20 ^° C. in a developer of the following composition:

N-methyl-p-amine-phenol sulfate 2.59 g

Ascorbic acid 10.09 g

Potassium metaborate 35.09 g

Potassium bromide 1.09 g

made up to 1 liter with water

pH 9.6

give a maximum density ₉ which is at least about 301 greater than the maximum density that is obtained when a corresponding test specimen is in the same developer for 6 minutes

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20 ° C is developed after being at about 20 C in for 5 minutes a 0.3 $ aqueous potassium ferricyanide bleach solution became.

According to a further particularly advantageous embodiment of the process of the invention, the process is carried out in the presence of at least one high molecular weight organic compound, and carried out in particular a high molecular weight organic sulfo compound. With these high molecular weight organic SuIfo compounds, which are preferably in the silver halide emulsion layer are accommodated, they are those of the following structural formula

R - SO ₃ M

where R is a polynuclear aromatic radical and M is a cation.

The use of such sulfonated compounds in combination with an electron acceptor and a halogen conductor compound results in a particularly high sensitivity of the emulsion layer.

The invention thus achieves that photographic images from recording materials with a blue-sensitive direct positive high contrast silver halide emulsion layer of high sensitivity and high contrast can be.

The developers used in practicing the method of the invention can be used as polyhydroxybenzene developing agents contain the usual known compounds of this type, for example hydroquinone, pyrocatechol, pyrogallol, isopropylhydroquinone, Methy! Hydroquinone, 2,5-dimethy! Hydroquinone, o-chlorohydroquinone, o-bromohydroquinone, 4-phenylpyrocatechol, 4-phenethylpyrocatechol, 4-phenylpropylpyrocatechol, 4-t.-butylpyrocatechol, 4-n-butyrogallol and 4,5-dibromobrenz-

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catechin.

In addition, esters of these polyhydroxybenzene developer compounds are suitable for carrying out the process of the invention, d. H. for example, the formates and acetates of these compounds can be used.

The developer can be accommodated in the recording material itself are applied to the recording material from a layer on a special support, or but can be applied in the form of a solution.

It has proven particularly advantageous to carry out the "experienced" of the invention as a developer compound alone or at least for the most part a 1,4-dihydroxybenzoly compound to use.

The developing agent can be in various concentrations can be applied. It has been found particularly advantageous to use developers containing from about 12 to about 20 grams of developer compound contained per liter of developer.

The developer can also contain customary additives, for example Antioxidants, e.g. B. sodium sulfite, alkaline compounds to produce a pH of at least about 9.0, for example sodium carbonate, sodium hydroxide and the like., Retarder, ζ. Β. Potassium bromide, or sodium bromide, as well as complexing agents and the like. It has proven to be particularly advantageous to use a developer which contains a carbonyl bisulfite amine condensation product. Such Developer with an excess of free amine of about 0.075 moles per liter of developer and a dihydroxybenzene devi Ekler connections are known and are for example in the Belgian patent 704 5 95 and the French U.S. Patent 1,539,407.

821/18 2 3

The use of developers that contain:

1. Sodium formaldehyde bisulfite or a carbonyl bisulfite amine and

2. 0.01 to about 0.05 moles of sulfite ions.

Generally such developers have a pH of at least 9.0.

The nafium formaldehyde bisulfite can be used in various concentrations are used, expediently in concentrations of about 40 to 80 g per liter. Preferably it will be shared with one Alkali metal sulfite is used. However, the sodium formaldehyde bisulfite can also be generated in situ, when in use a mixture of formaldehyde or paraformaldehyde and sodium sulfite in the developer.

It has also proven advantageous to carry out the process of the invention in the presence of an alkylene oxide. Alkylene oxides suitable for carrying out the process of the invention are, for example, polyethylene glycol, polyethylene glycol oleyl ethers, Polyethylene glycol cetyl ethers, polyethylene oxide derivatives, Block copolymers, for example those made from blocks of polyoxypropylene, polyoxyethylene and the like., As well as water-soluble organosilicon polyalkylene oxide polymers. You can z. B. used in the developer and / or the emulsion layer / " The silver halide emulsion layer of the recording material used in the process of the invention, which is an organic Compound that accepts or takes up electrons is sensitive to blue. Sensitive to blue means that when the emulsion layer is exposed to light having a wavelength range of 350 to 500 millimicrons, inverted images are produced

let generate.

/ - be.

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The silver halide emulsion can further be spectrally sensitized so that reversal images are formed when the emulsion layer with light of other wavelengths of the spectrum, for example light of the green and red range of the electromagnetic spectrum is exposed. However, all of these emulsions have the property that the layers produced from this produce inverted images when exposed to light in the blue region of the spectrum.

Suitable electron acceptors are photoelectron acceptors or absorbing compounds or desensitizing dyes. Among the particularly advantageous desensitizers include, for example, the compounds known from British patent specification 723 019.

Particularly advantageous electron acceptors are those which have certain polarographic half-wave potentials, i.e. certain oxidation-reduction potentials determined by polarographic methods exhibit.

The determination of the polarographic, cathodic half-wave potential can with a 1 χ 10 molar solution of the electron acceptor in a solvent, for example methanol, which is 0.05 molar with respect to lithium chloride and is done using a mercury drop electrode. The polarographic Half-wave potential of the most positive cathodic wave can be referred to as E. Accordingly can Anodic measurements are carried out with 1 χ 10 molar aqueous solvent solutions, for example with methanolic Solutions of the electron acceptor which are 0.05 molar with respect to sodium acetate and 0.005 molar with respect to acetic acid, where an electrode consisting of a paste of pyrolytic graphite and the yoltarnetrishe half-wave potential can be used the most negative anodic rendition is referred to as E. In both cases, the reference electrode

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be an aqueous silver-silver chloride (saturated with potassium chloride) electrode at 20 ^° C.

Further details of such electrochemical determination methods are described, for example, in the book "New Instrumental Methods in Electrochemistry" by Delahay, Verlag Interscience Publishers, New York, New York, 1954; the book by Kolthoff and Lingane, "Polarography", 2nd edition, Interscience Publishers, New York, New York, 1952; the journal "Analytical Chemistry", 3> 6_, 2426 (1964) and "Analytical Chemistry ", 30, 1576 (1958).

The plus and minus signs correspond to the guidelines of the IUPAC (International Union of Pure and Applied Chemistry), which were developed in Stockholm in 1953.

The use of compounds has proven to be particularly advantageous proved to be electron acceptors that are organic in nature and have a polarographic anodic half-wave potential (E) and a polarographic cathodic half-wave potential (E), whose values add a positive Total.

The use of compounds with the half-wave potentials described has proven to be particularly advantageous, which at the same time spectrally the photographic silver halide emulsion with respect to light of a wavelength of at least about 430 my, preferably from about 430 to about 800 my, sensitize. It has proven to be particularly advantageous proved to use such compounds which spectrally sensitize the emulsion so that the ratio of relative kinus blue sensitivity to relative blue sensitivity is greater than 7, preferably greater than 10, when the emulsion is exposed to a tungsten light source and between Light source and emulsion Wratten filter No. 16 or No. 35 plus

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38A are connected. Such electron acceptors can be called "spectrally sensitizing electron acceptors" describe.

According to a particularly advantageous embodiment of the method According to the invention, there is provided a recording material with a direct positive, high-contrast silver halide emulsion layer used as the electron acceptor one or more cyanine dyes, especially imidazoquinoxaline dyes contains, for example of the type known from Belgian patent 660,253. Excellent results will be for example obtained with cyanine dyes, which have an indole nucleus have whose aromatic ring is substituted in the 2-position, d. H. as particularly advantageous cyanine dyes those have been found which have a 2-aromatically substituted indole nucleus.

A particularly advantageous class of spectral sensitizers Electron acceptors consists of bis (1-alkyl-2-phenylindole-3) -trimethine cyanines, which are known, for example, from US Pat. No. 2,930,694. Another special one advantageous class of dimethine cyanine dyes of this type is known from British patent specification 970 6OT.

The electron acceptors can be used in various concentrations. Preferably they are in concentrations from about 100 mg to about 2 g per mole of silver halide is used.

Typical electron acceptors suitable for carrying out the method of the invention are, for example:

, 1-dimethyl-2 _> 2'-diphenyl-3 _> 3 ^l -indolocarbocyanine bromide

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19454C9

CH = CH-CH

^C 6 ^H 5 ^C 6 ^H 5

Br

CH.

CH.

2.2 ^f -Di-p-methoxypheny1-1.1 • -dimethy1-3 ^ • -indolocarbocyanine • bromide

CH

CH = CH-CH

CH.

Br '

OCH

1,1'-Dimethyl 1-2,2 ', 8-triphenyl-3,3'-indolocarbocyanine perchlorate

N
CH

CH = CH-C

^C 6 ^H 5 ^C 6 ^H 5

CH ₃ ClO ₄

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1,1 '»3,3'-Tetraethylimidazo ^' 4,5 _: b7quinoxalinocarbocyanine chloride

CV

Further examples of how to carry out the method of the invention suitable electron acceptors are:

Phenosafranine, pinacryptol yellow, 5-m-nitrobenzylidene rhodanine, Sm-nitrobenzylidene-S-phenylrhodanine, 3-ethyl-Sm-nitrobenzylidene rhodanine, 3-ethyl-5- (2,4-dinitrobenzylidene) rhodanine, 5-o-nitrobenzylidene-nitrobenzylidene , 1 ', S-diethyl-o-nitrothia-Z'-cyanine iodide, 4-nitro-o-chlorobenzotriazole, 3,3'-diethyl-6,6'-dinitro-Q-phenylthiacarbocyanin iodide, 2-Cp-dimethylaminophenyliminomethyl) benzothiazole ethyl sulfate , Crystal violet, 3,3 · - diethyl-6,6'-dinitrothiacarbocyanine ethyl sulfate, 1 ', 3-diethyl-6-nitrothia-2'-cyanoindide, 1, S-diamino-S-methylphenazinium chloride, 4-nitro-6-chlorobenzotriazole , 3,3'-di-p-nitrobenzylthiacarbocyanine bromide, SjS'-di-p-nitrophenylthiacarbocyanine iodide, 3,3'-di-o-nitrophenylthiacarbocyanine perchlorate, 3,3 · -dimethyl-9-trifluoromethylthiacarbocyanine iodide, 9- (2 _? 4- Dinitrophenylmercapto) -S ^ '- diethylthiacarbocyanin iodide, bis (4,6-diphenylpyryl-2) -trimethinecyanine perchlorate, anhydro-2-p-dimethylaminopheny1-iminomethyl-6-nitro-3- (4-sulfobutyl) benzothiazolium hydroxide, 1- (2- Benz othiazolyl) -2- (p-dimethylaminostyryl) -4,6-diphenylpyridinium iodide, 1,3-diethyl-5 - ^ "i, 3-neopentylene-6- (1, S, 3-trimethyl-2-indolinylidene) -2 , 4-hexadienylidene7-2-thiobarbituric acid _>

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2,3,5-triphenyl-2H-tetrazolium chloride, 2- (4-iodophenyl) -3- (4-nitrophenyl) -S-phenyl-tetrazolium chloride, 1-methyl-8-nitroquinolinium methyl sulfate, 3,6-bis ^? - (3-ethyl-2-benzothiazolinylidene) -2-butenyliden7-1,2,4,5-cyclohexantetron, anhydro-6,6'-dinitro-3,3 * -di (3-sulfopropyl) thiacyanine hydroxide, sodium salt, 1, 3-diethyl-1 · -methyl-2 · -phenylimidazo / "4,5-b7-quinoxalino-3'-indolocarbocyanin iodide, 1,3-diallyl-2 ;; ^ ^l " 2- (3,5-dimethyl-1-phenyl -4-pyrazolyl) viny ^ imidazo ^^ jS-b ^ quinoxalinium iodide, 1,3-diethyl-1'-methyl-2 ^ ~ (2-methyl-5-oxo-3-phenyl-3-isoxazolin-4-yl) vinyl 7-o-nitrobenzothiazolium methyl sulfate.

According to a particularly advantageous embodiment, a photographic material having a silver halide emulsion layer used, the silver halide grains of which have an average kojirnd diameter of about 0.01 to about 2 microns, preferably from about 0.02 to about 1 micron. The silver halide grains can have any known shape, i.e. be cubic or octahedral, for example.

The fogging of the silver halide grains can also be known Process take place chemically or physically. For example, the obfuscation can be achieved through chemical sensitization against haze, with particularly advantageous results being obtained when methods are used be, for example, from the journal "Science et Industries Photographiques", Volume XXVIII, 1957, Pages 57-65 are known.

For example, by exposure to the silver halide grains obscured by high intensity light and by the action of reducing compounds, for example Thiourea dioxide or stannous chloride, reduction-veiled or the concealment can. by gold or a other noble metal compound can be brought about. According to a

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In an advantageous embodiment of the method of the invention, concealment can be brought about by the combined use of a reducing agent and a gold compound or another noble metal compound with a metal that is more electropositive than silver, for example rhodium, platinum or iridium. Recording materials suitable for carrying out the process of the invention have silver halide emulsion layers with fogged silver halide grains which give a density of at least 0.5 when they are developed for 5 minutes at 20 ^° C. in a developer of the specified composition without being exposed in the form of a direct positive emulsion layer which has been applied to a layer support in such a way that 50 to about 1000 mg of silver are used ^{on a support area of 0.09 m 2 (1 sq.ft.).}

This can advantageously be used to carry out the method The recording material used according to the invention thus contain silver halide grains in the emulsion layer, which by use a reducing compound and a gold or other noble metal compound have been veiled. Particularly Advantageous results are obtained when low concentrations of reducing agent and noble metal compound are used Use of such combinations are used, namely because such emulsions are characterized by that they can be easily unveiled using a chemical bleaching process.

It is known that one weight equivalent of a reducing compound makes one weight equivalent of silver halide to silver able to reduce. To produce fogged silver halide grains caused by rapid loss of fog during Bleaching, much lower concentrations than one weight equivalent of reducing agent are used for concealment. It has therefore proven to be particularly advantageous for example, per mole of silver has been shown to obfuscate

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use less than about 0.06 milliequivalents of the reducing agent. Concentrations have proven to be useful Reducing agent from about 0.0005 to about 0.06, preferably from about 0.001 to about 0.03 milliequivalents of reducing agent per mole of silver halide.

As a particularly advantageous reducing agent for effecting fogging of silver halide grains in combination with a gold or other noble metal compound with a metal that is more electropositive than silver is thiourea Dioxide proven. This compound is preferably used in concentrations of about 0.05 to about 3, especially about 0.1 to about 2 mg per mole of silver halide or about 0.005 to about 0.03 millimole per mole of silver halide is used.

Another particularly advantageous reducing compound to achieve a concealment is stannous chloride, which is preferably in a concentration of about 0.05 to about 3 mg of stannous chloride per mole of silver halide is used.

The use of the reducing compound and the gold compound or other noble metal compounds to achieve this fogging of the silver halide grains at low concentrations results in direct positive silver halide emulsions with a particularly outstanding photographic sensitivity.

Apart from thiourea dioxide and stannous chloride, as a reducing fogging agent, for example, hydrazine and phosphonium salts, e.g. B. Tetra (hydroxymethyl) phosphonium chloride, d. H. Use compounds as known from U.S. Patents 3,062,651 and 2,983,609, and also other stannous salts, such as those known from US Pat. No. 2,487,850, or polyamines, e.g. B. diethylenetriamine, as known from US Pat. No. 2,519,698, or polyamines, e.g. B. Spermine, as described in the US patent 2 5 21 925 are known, or bis (ß-aminoethyl) sulfide

10982Ί / 1623

with its corresponding water-soluble salts, according to the USA patent 2,521,926.

The gold compounds used for obfuscation can consist of conventional gold salts that are photographic for obfuscation shear silver halide grains are known. Such gold salts are, for example, from US Patents 2,399,083 and 2,642,361 known. Typical gold compounds suitable for masking are, for example, potassium chloroaurite, potassium aurithiocyanate, Potassium chloroaurate, auritrichloride, and 2-aurosulfobenzοthiazole methochloride.

The concentration of gold compounds used to obscure the silver halide grains can vary widely be. It has proven to be particularly advantageous to use the gold compounds in concentrations of approximately 0.001 to approximately To use 0.01 millimoles per mole of silver halide "

A particularly advantageous gold compound is potassium chloroaurate, with which, for example, advantageous obscurations can be made at concentrations of less than about 5 mg per mole of silver halide, preferably at concentrations of about 0.05 up to about 4 mg per mole of silver halide.

If a gold compound is used together with a reducing compound for concealment, the gold compound forms preferably the majority of the compound combination, wherein the ratio of gold compound to reducing agent is advantageously in a range of about 1: 3 to about 20: 1, in particular 2: 1 to about 20: 1.

The silver halide grains are advantageously obscured by first applying the reducing compound and then the gold compound is applied. Of course, the gold connection can also initially be used for

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Application can be applied or both connections can be carried out at the same time be used.

The fogging of the silver halide grains can be carried out before the emulsion is coated on a support or after the emulsion is coated on a support. The reaction conditions during fogging of the silver halide grains can vary widely. As appropriate, it has been found when the pH value in the blurring between about 5 and about 7, and the pAg value between about 6 and about 9 is and further when a temperature of about 40 to about 10O ⁰ C, preferably from about 50 to about 70 ⁰ C is maintained. During the fogging of the silver halide grains, they can be suspended in any of the conventional silver halide binders, for example gelatin, which can be used, for example, in concentrations of from about 50 to about 200 g per mole of silver halide.

According to a further particularly advantageous embodiment of the method of the invention, a recording material with a silver halide emulsion layer is used, the silver halide grains of which are characterized by a practically uniform diameter frequency distribution and which have also been obscured by means of a low concentration of a reducing agent and a gold compound. Such silver halide grains can be quickly unveiled by chemical bleaching, ie they lose their haze very quickly by chemical bleaching. The silver halide grains can be considered particularly advantageous when they lose at least about 25%, preferably at least about 40% of their haze when they ^{are bleached for 5 minutes at 20 °} C. in a potassium ferricyanide bleach bath of the composition specified below. Such loss of fog can easily be illustrated by coating the silver halide grains in the form of a photographic silver halide emulsion on a support such that a maximum density of at least 1.0 is obtained when

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the emulsion layer viird developed for 6 minutes at about 20 ⁰ C in a developer of the composition indicated and has been developed by comparison of the density of the emulsion layer having the density of an emulsion layer formed in a corresponding manner, the 6 minutes at 20 ⁰ C in the same developer after it has been bleached for about 5 minutes at 20 ^° C. in a 0.3% strength aqueous potassium ferricyanide solution. The maximum density of the unbleached emulsion layer is then approximately at least 30%, generally at least 60% greater than the maximum density of the bleached emulsion layer.

The silver halide emulsion layer of the recording material preferably contains a silver halide which is at least 70 mol% from chloride, less than 5 mol% from iodide and for Remainder consists of bromide. Recording materials with silver halide emulsion layers are also suitable for carrying out the process, whose silver halide consists of 100 mol% chloride.

According to a particularly advantageous embodiment of the method According to the invention, a recording material is used whose silver halide emulsion layer has fogged silver halide grains, an electron acceptor and a halogen conductor compound contains. This combination makes it possible, for example, to make the background density of the emulsion significantly Reduce.

Particularly advantageous for carrying out the method of the invention Halogen conductor connections can also be determined by their polarographic half-wave potentials, i.e. H. their oxidation-reduction potentials, which are determined by polarographic means. The cathodic measurements

-4

can with a 1.x 10 molar solution of the halogen conductor compound in a solvent such as methanol, the

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with respect to lithium chloride is 0.05 molar, and can also be carried out using a dripping mercury electrode, with the polarographic ilal step potential of the most positive cathodic step being referred to as E, ->. Anodic measurements can be carried out accordingly with a 1-10 molar aqueous solvent solution, for example with methanolic solutions of the halogen conductor compound, which are 0.05 molar with respect to sodium acetate and 0.005 molar with respect to acetic acid, the electrode being made from a carbon paste or from pyrolytically obtained Graphite existing electrode can be used, whereby the voltametric half-step potential or voltarnetric half-peak potential of the most negative anodic excitation can be designated with E. ^ For all measurements, the comparison electrode can consist of an aqueous silver-silver chloride (saturated potassium chloride) electrode at 20 ^° C.

The determination of the polarographic half-wave potentials can for example, by methods as described in more detail in the book by Delahay "New Instrumental Methods in Electrochemistry, Interscience Publishers, New York, New York, 1954; in the book by Kolthoff and Lingane "Polarography", 2nd edition, Interscience Publishers, New York, New Vork, 1952 and the journal "Analytical Chemistry", JS6, 2426 (1964) and, 30, 1576 (1958).

Particularly suitable compounds which can be used as halogen conductor compounds are organic and inorganic compounds with a polarographic anodic half-wave potential E _{f Λ} of less than 0.85 and a polarographic cathodic half-wave potential E-. Which is more negative than -1.0, the Provisions of the IÜPAC agreement apply.

10 9 8 2 1/16 23

Those with an anodic half-wave potential have proven to be a particularly advantageous class of halogen conductor connections which is less than 0.62 and which also have a cathodic half-wave potential which is more negative than -1.3 is.

Particularly advantageous halogen conductor connections that are used for the production of the recording material are spectral sensitizing merocyanine dyes of the following general structural formula:

Il

B C = (L-L) - C,

where mean:

A the to complete a sour hetero

cyclic nucleus required atoms, d. H. for example the atoms needed to complete

d completion of a rhodanine or 2-thiohydantoin ring

required are;

B to complete a basic stick

material-containing heterocyclic nucleus required atoms, i.e. for example the atoms required to complete a benzothiazole, naphthothiazole or benzoxazole nucleus are;

L is a methine residue, for example of the formulas:

-CH =, -C = or -C = and

I I

CH ₃ C ₆ H ₅

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η = 0, 1 or 2.

Typical merocyanine dyes suitable for carrying out the process of the invention are, for example:

3-carboxymethyl-5 - ^ "(3-ethyl-2-benzothiazolinylidene) ethylidene-rhodanine;

3-ethyl-5 - / "i- (4-sulfobutyl) -4- (1H) -pyridylidene-7-rhodanine, Sodium salt;

3-carboxymethyl-5 ^ ~ (3-methyl-2- (3H) -thiazolinylidene) -isopropylidene-thodanine;

3-Carboxymethy1-5 - ^ * 3- (sulfopropyI) -2-thiazolinyliden7-äthylidenrhodanin, Sodium salt;

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

1-carboxymethyl-5 - ^ "(3-ethyl-2-benzothiazolinylidene) ethylidene7-3-pheny1-3-thiohydantoin;

A- £ (1-ethylnaphtho7-1 »2-d ^" thiazolin-2-ylidene) -1 methylethylidene7-3-methyl-1- (4-sulfophenyl) -2-pyrazolin-5-one and

4 - ^ "(3-Ethyl-6-nitro-2-benzothiazolinylidene) -ethylidene 7-3-phenyl-2-isoxazolin-5-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 production of merocyanine dyes, which can be used as halogen conductor compounds can be used are known, for example, from U.S. Patents 2,493,747 and 2,493,748.

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The concentration of the halogen conductor compound can vary widely be. It has proven to be useful to use the Halogenleiterverbiftdung in concentrations from about 25 mg to about 20 g, preferably from about 150 to about 1000 mg per mole of silver halide to use.

As already mentioned, the process of the invention can advantageously be carried out in the presence of a high molecular weight organic Sulpho compound can be carried out when a particularly high Emulsion sensitivity is desired. Such suIfο connections have proven to be suitable, those from polynuclear "consist of aromatic compounds with at least one sulfo group. The term "polynuclear aromatic" means that the compound should have at least 2 or more benzene nuclei fused to one another, as they are, for example, in Naphthalene or pyrene are present, or at least 2 benzene rings or other aromatic rings that are directly linked to one another are, in which case, for example, diphenyl, terphenyl or quaterphenyl compounds are present. Furthermore you can also at least 2 benzene rings can be linked to one another by an aliphatic bond. In the given general Structural formula:

k R-SO ₃ M

thus R represents a polynuclear aromatic radical of the specified Definition and M is a cation, for example a hydrogen atom or a water-soluble cationic salt group, for example an alkali metal atom, e.g. B. a sodium or potassium atom, or an ammonium group or a triethylammonium, Triethanolammonium or pyridinium group.

109821/162 3

Typical sulfo compounds of the specified structural formula suitable for carrying out the process of the invention are, for example, the sodium salts of bis (s-triazin-2-ylamino) stilbene-2,2 ^f -disulfonic acid (for example Calcofluor White-MR and Leucophor B) and also sodium -6 -. (4-methoxy-3-sulfov-phenylacryloyl) pyrene; 3,4-bis (4-methoxy-3-sulfobenzamido) -dibenzo-thiophenedioxide, sodium salt; 4 ', 4 "-Bis (2,4-dimethoxy-5-sulfobenzamido) -p-terphenyl, disodium salt; Chyrsen-6-sulfonic acid, sodium salt; 4,4'-Bis ^" 2-phenoxy-4- (2- hydroxyethylamino) -1,3,5-triazin-6-ylamino7stilbene-2,2'-disulfonic acid, disodium salt.

The SuIfoverbindungen can in different concentrations can be applied. It has proven advantageous to use them in concentrations of about 0.02 to about 10 g per mole of silver halide to use. The halogen conductor compounds and / or electron acceptors can also be used together with water-soluble Halide salts can be used, for example bromide salts, as described in Belgian patent 695 363 are known.

The silver halide emulsion layer of the recording material used in carrying out the process of the invention can also contain the usual known additives, for example gelatine plasticizers, coating auxiliaries, Antifoggants, e.g. B. azaindenes, and conventional hardeners, for example aldehyde hardeners, e.g. B. formaldehyde, mucochloric acid, Glutaraldehyde bis (sodium bisulfite), maleindialdehyde, Aziridines, dioxane derivatives and oxypolysaccharides.

For the preparation of the silver halide emulsion layer of the record The usual known hydrophilic, water-permeable binders can also be used for the rest of the processing material, for example Gelatine, colloidal albumin, polyvinyl compounds,

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Cellulose derivatives, acrylamide polymers and the like. Even Mixtures of different binders can be used. The binders can also include dispersed polymerized vinyl compounds included, for example, from U.S. Patents 3,142,568; 3,193,386; 3 062 674 and 3 220 884 are known. Such polymerized vinyl compounds can, for example, from water-insoluble polymers of Alkyl acrylates and alkyl methacrylates ^ acrylic acid, sulfoalkyl acrylates or sulfoalkyl methacrylates.

The substrate of the invention for carrying out the method The recording material used can consist of one of the customary known layer supports which are used for the production of photographic Recording materials are known exist. Typical supports can consist of, for example Cellulose nitrate films, cellulose ester films, polyvinyl acetal films, polystyrene films, polyethylene terephthalate films and Sheets made of appropriate materials or made of glass, metal, paper and the like. The support can for example also consist of paper coated with an α-olefin polymer was made, in particular with a polymer an α-01efin with 2 or more carbon atoms, for example with polyethylene, polypropylene or an ethylene-butene copolymer.

It has proven particularly advantageous to use the method of the invention in an automatic continuous developing device perform as described, for example, in US Patents 3,025,779; 3,078,024; 3,122,086; 3,149,551; 3,156,173 and 3,224,356 are known. In such devices, the recording materials can by continuous Transport into and out of at least one processing or developer solution to be developed. Developing devices having transport rollers have proven to be particularly advantageous of the type known from US Pat. No. 3,025,779.

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The recording materials used for carrying out the method of the invention can also advantageously common known onium salts, e.g. quaternary ammonium salts, Sulfonium salts and / or phosphonium salts contain to the Development speed without adversely affecting the Increase contrast. Onium salts suitable for carrying out the process are, for example, from the USA patents 2,271,623; 2,944,898; 2,944,900; 2,275,727 and 2,288,437 and from British patent specification 1,067,958. In advantageous When using such onium salts, concentrations of about 0.01 to about 2.0 g of onium salt per mole can be used Silver can be used in the silver halide emulsion layer.

To increase the speed of development, the silver halide emulsion further optionally from about 0.005 to about 2.0 grams of a 3-pyrazolidone per mole of silver are added. Suitable pyrazolidones are known, for example, from US Pat. No. 2,751,297. They can be broken down by the following general Represent structural formula:

0 = -

X - N CHR ₁

where mean:

X is a hydrogen atom or an acetyl radical;

R is a heterocyclic radical or an aryl radical from the benzene or naphthalene series;

10982 Ί / 1623

R _{1 is} a hydrogen atom, an alkyl radical or an aryl radical of the benzene or naphthalene series and

R ₂ and R, each a hydrogen atom or an alkyl radical.

Typical suitable 3-pyrazolidones of the given structural formula are for example:

i-phenyl-3-pyrazolidone, S-methyl-3-pyrazolidone, 1-phenyl-5-pheny1-3-pyrazolidone, 1-phenyl-S-methyl-S-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 in one of the silver halide emulsion layers adjacent layer can be accommodated.

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

example 1

A pure silver chloride photographic emulsion was fogged with 4 mg of thiourea dioxide per mole of silver.

100 mg of 1,1'-diethyl-2,2'-cyanine chloride CI) per mole of silver were added as electron acceptor to a portion of the emulsion. In addition, 200 mg of the halogen conductor compound 3-carboxymethyl-5 ^ ~ (3-methyl-2- (3H) -thiazolinylidene) isopropylidene-rhodanine were added to the sample per mole of silver (II) added.

The emulsion obtained was then applied to a conventional cellulose acetate layer support in such a way that 120 mg of silver accounted for ^{a support area of 0.09 m 2 (1 sq.ft.).}

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The recording material obtained and a comparative material rial with a silver halide emulsion layer without additives was then exposed in a sensitometer and then Developed for 1.5 minutes at 20 ° C in a developer of the following composition

Water 500 ml

Sodium sulfite (dehydrated) 30.9 g

Paraformaldehyde 7.59 g

Sodium bisulfite 2.29 g

Boric acid (crystals) 2.59 g

Hydroquinone 22.59 g

Potassium bromide 1.69 g

made up to 1 liter with water

The following results were obtained:

Relative. _{D ß}

Additions Sensitivity max min

no no reversal

I + II 229 1.32 0.06

The recording material with the emulsion layer which contained the compounds I and II shows a reverse effect when exposed to blue light alone and developed in the developer described.

Example 2

A pure silver chloride photographic emulsion was made with 0.125 mg thiourea dioxide and 1 mg potassium chloroaurate per Mole of silver veiled,

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At various proportions of the emulsion, the dyes I and II described in Example 1 were added to those in the following Concentrations given in the table added.

The resulting emulsions were then applied to cellulose acetate supports in such a way that 120 mg of silver were ^{applied to a support area of 0.09 m 2 (1 sq.ft.).} The recording materials were then exposed in a conventional sensitometer and developed in the developer described in Example 1 at 20 ^° C. for 1.5 minutes.

The following results were obtained:

dye mg
Mole Dye/
Ag Relative
Sensation
opportunity D. Max D. min II 200 289 1 , 63 0 , 18 II
I. 200
100 795 1 , 48 0 , 05

100

100

1.44

0.18

Example 3

A silver chlorobromide emulsion was added by simultaneous addition of 9/10 moles of sodium chloride, 1/10 of potassium bromide and 1 mole of silver nitrate within 50 minutes at 50 ^° C. to a solution of 43 g of gelatin. A further 37 g of gelatin were then added, whereupon the emulsion was allowed to cool and washed. The emulsion was then fogged by heating it for 20 minutes with 0.3 mg of thiourea dioxide per mole of silver to 65 ⁰ G by adding 0.2 mg of chloroaurate per

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Mol silver was added and the emulsion was ^{heated to 65 °} C. for 50 minutes and further heated until a high contrast was achieved and the emulsion could be developed to maximum density without exposing it.

Before the emulsion was applied to a support, it was 15 mg of 1-phenyl-4-methyl-3-pyrazolidone per mole of silver and 400 mg of 1,3-diethyl-1'-methyl-2-phenylimidazo ^ ~ 4,5-b7-quinoxalino-3'-indolocarbocyanine iodide (III) added as electron acceptor.

The emulsion was then applied to a polyester base made of polyethylene terephthalate, exposed and exposed Developed for 2 3/4 minutes in a developer of the composition given in Example 1, fixed, washed and dried.

It became a direct positive image with the following characteristics Receive data:

^D max ^D min contrast

3.68 0.29 4.40

Correspondingly favorable results were obtained when as Electron acceptor one of the following compounds was used:

Anhydro-6,6'-dinitro-3,3'-di (3-sulfopropyl) thiacyanine hydrodide, sodium salt; 1,3-diethyl-i -methyl-2 ^f -phenylimidazo ^ "4,5-b7-quinoxalino-S'-indolocarbocyanin iodide, 1, S-diallyl ^ - ^^ - CSjS-dimethyl-i-phenylM-pyrazolyl) vinyl7imidazo ^ ~ 4,5-b7quinoxalinium iodide and 1,3-diethyl-1 · -methyl-2'-phenylimidazo ^ "4,5-b7quinoxolino-S'-indolocarbocyanine iodide.

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Example 4

Following the procedure described in Example 3, an emulsion was obtained made and veiled.

The emulsion was divided into three parts, followed by the parts added:

1. 400 mg of the halogen conductor compound II from Example 1;

2. 400 mg of the halogen conductor compound II described in Example 1 and 200 mg of that described in Example 3 Halogen acceptor per mole of silver

3. 400 mg of the halogen conductor compound II described in Example 1 per mole of silver and 50 mg of 1.1 ^f- di-n-butyl-4,4'-bi-pyridinium diperchlorate (N-butyl paraquate) CIV) per mole of silver.

The individual recording materials were exposed and then for 1 3/4 minutes in a developer from in Example 1 developed into direct positive images of the following characteristic data:

additions Relative
Sensation
opportunity γ Max min II 100 1.18 2.70 0.82 II + III 100 5.50 2.72 0.04 II + IV 138 4.90 2.74 0.06

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The addition of the halogen conductor compound resulted in good sensitivity, but the reversal effect was low (higher D · value) · By adding a halogen conductor compound and an electron acceptor, a high contrast became a low one D. Value and a sharp sag reached, mm °

Correspondingly favorable results were obtained when the halogen conductor compound 3-carboxymethyl-5- ^ ~ 3 (sulfopropyl) 2-thiazolinyliden7äthylidenrhodanin, sodium salt was used.

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Claims (15)

PATENT CLAIMS Process for the production of photographic images by developing an exposed photographic recording material with a blue-sensitive direct positive high-contrast silver halide emulsion layer, the silver halide of which _{consists of at least 50 mol%, preferably at least 70 mol% f} of silver chloride and in which the recording material is developed with a developer, the silver halide developing agent consists entirely or almost entirely of a polyhydroxybenzene developer compound, characterized in that a recording material is used with a silver halide emulsion layer which contains an organic electron acceptor and a halogen conductor compound and the silver halide grains of which are fogged. 2. The method according to claim 1, characterized in that one a recording material having a silver halide emulsion layer used, the fogged silver halide grains of which contain a halogen conductor compound adsorbed, their polarographic anodic half-step potential is lower than 0.85 and whose polarographic cathodic half-wave potential is more negative than -1.0. 3. The method according to claim 2, characterized in that one a recording material is used which contains a merocyanine dye as halogen conductor compound, 4. Process according to Claims 1 to 3, characterized in that that hydroquinone is used as the polyhydroxybenzene developer compound. 6 2 3 5. Process according to Claims 1 to 4, characterized in that a developer is used which contains a carbonyl bisulfite Contains amine condensation product. 6. Process according to Claims 1 to 5, characterized in that a developer is used which contains sodium formaldehyde bisulfite and is 0.01 to about 0.05 molar in free sulfite ions. 7. The method according to claims 1 to 6, characterized in that that a recording material is used whose silver halide emulsion layer a suIfο connection of the following Formula contains: R-SO ₃ M where R is a polynuclear radical with at least two fused benzene rings and M is a cation. 8. Process according to Claims 1 to 7, characterized in that a recording material with a silver halide emulsion layer is used used whose electron acceptor a polarographic anodic half-wave potential and a has cathodic half-wave potential, their values add up to a positive sum. 9. Process according to Claims 1 to 8, characterized in that a recording material with a silver halide emulsion layer is used used whose electron acceptor consists of a cyanine, in particular imidazoquinoxaline dye. S, Π / 1623 10. The method according to claims 1 to 9, characterized in that a recording material with a silver halide emulsion layer used, their silver halide grains obscured with a reducing agent and a gold compound are. 11. The method according to claims 1 to 10, characterized in that there is a recording material with a silver halide emulsion layer used, the silver halide grains with about 0.0005 to about 0.06 milliequivalents of a reducing ^ means per mole of silver halide and about 0.0001 to about 0.01 millimoles of a gold compound per mole of silver halide are obscured. 12. The method according to claims 1 to 11, characterized in that a recording material is used with a silver halide emulsion layer, the silver halide grains are such that they can be used as a test piece after application to a conventional support in the form of a photographic silver halide emulsion to produce a maximum density of at least about 1, after 6 minutes of development at 20 ^° C. in a developer with the following composition: N-methyl-p-aminophenol sulfate 2.59 g Ascorbic acid 10.09 g Potassium metaborate 35.09 g Potassium bromide 1.09 g made up to 1.0 liter with water pH = 9.6 result in a maximum density that is at least about 30% greater than the maximum density obtained when 109821/1623 a corresponding test specimen is developed 6 minutes Pichen the developer at 2O ⁰ C, after being bleached for 5 minutes at about 2O ⁰ C in a 0.3% aqueous Kaliumferricyanidbleichlösung. 13. The method according to claims 1 to 12, characterized in that that the recording material is developed in an automatically operating transport device. 14. Photographic recording material for carrying out the method according to claims 1 to 13, consisting of a support and at least one blue-sensitive direct positive silver halide emulsion layer with fogged Silver halide grains composed of at least 50 mol%, preferably at least 70 mol%, of silver chloride consist, characterized in that the silver halide emulsion layer has an electron acceptor and a halogen lead te r connection contains. 15. Photographic recording material according to claim 14, characterized in that the silver halide emulsification layer 1) an electron acceptor, a polarographic one Has anodic half-wave potential and a cathodic half-wave potential, whose values add a positive Sum, and 2) a halogen conductor connection with 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. 109821/1623