Photographic high contrast silver halide elements and process using them

Abstract: 1. Aryl hydrazides of the formula: where X is SO₂ or CO, R¹ and R² (which may be the same or different) each represents an aliphatic group of at least 2 carbon atoms, a cycloaliphatic group, a substituted or unsubstituted aromatic group or a substituted or unsubstituted heterocyclic group; R³ represents -(CH₂-) n - where n is an integer of 1 to 4, preferably 1 or 2, R⁴ represents a substituted or unsubstituted aliphatic or a substituted or unsubstituted aromatic group, R⁵ represents hydrogen or an aliphatic, aromatic or heterocyclic group any of which groups being substituted or unsubstituted, provided that when X is SO₂, R⁵ is not hydrogen, and Ar represents an aromatic group which may contain alkyl or alkoxy groups in addition to those substituents shown, are effective nucleators for high contrast photographic silver halide materials.

Description: This invention relates to photographic high contrast silver halide elements and to methods of obtaining high contrast photographic images therewith. For many years the very high contrast photographic images needed in the graphic arts and printing industries were obtained by developing a 'lith' emulsion (usually high in silver chloride content) in a hydroquinone, low sulphite, 'lith' developer by the process known as infectious development. However, such low sulphite developers are inherently unstable and are particularly inappropriate for machine processing. Recently, emulsions containing hydrazide nucleating agents have been used and processed in a developer with conventional amounts of sulphite, hydroquinone and possibly metol or a pyrazolidone. Many hydrazides have been proposed for incorporation in such high contrast silver halide materials, for example in US Patents 4,323,643, 4,278,748, 4,031,127 and 4,030,925. In particular, US Patent 4,323,643 describes aryl hydrazides of the formula: wherein R¹ and R² each represents hydrogen, an aliphatic group, an aromatic group, or a heterocyclic group; R³ represents hydrogen or an aliphatic group, and X represents a divalent aromatic group. European Patent Application 196,626 also descrives photographic materials useful for obtaining high contrast negative images using various hydrazide nucleating agents. These agents include sulfonamidophenyl hydrazides as well as alkyl substituted phenoxybutyramidohydrazide compounds. It is known that when hydrazides from different classes are used in combination, a superior result can often be obtained. Some known commercial products contain such a combination. The present invention provides novel hydrazide nucleators effective in high contrast photographic material some of which when used alone provide as good a photographic material as was previously obtainable only with a combination of hydrazides. According to the present invention there is provided an aryl hydrazide of the formula: where X is SO₂ or CO, R¹ and R² (which may be the same or different) each represents an aliphatic group of at least 2 carbon atoms, a cycloaliphatic group, a substituted or unsubstituted aromatic group or a substituted or unsubstituted heterocyclic group; R³ represents -(CH₂-) n - where n is an integer of 1 to 4, preferably 1 or 2, R⁴ represents a substituted or unsubstituted aliphatic or a substituted or unsubstituted aromatic group, R⁵ represents hydrogen or an aliphatic, aromatic or heterocyclic group any of which groups being substituted or unsubstituted, provided that when X is SO₂, R⁵ is not hydrogen, Ar represents an aromatic group which may contain alkyl or alkoxy groups in addition to R³ and OR⁴. Preferably the group - OR⁴ is ortho or para to the hydrazide group. The group R³ is preferably meta to the hydrazide group. These hydrazides may be incorporated into silver halide negative-working materials to provide very high contrast images of high image quality on development at a pH between 10.5 and 12.0 with little or no pepper fog. The present invention also provides a photographic element comprising a support and a layer of a photosensitive silver halide emulsion containing in or adjacent said layer an aryl hydrazide of formula (I) as defined above. Examples of groups which R¹ and R² may represent are alkyl groups of 2-12 carbon atoms, e.g. ethyl, propyl, butyl, n-pentyl, t-pentyl, n-octyl and n-dodecyl; cycloalkyl groups, e.g. cyclohexyl; aryl groups, e.g. phenyl, naphthyl nitrophenyl, tolyl; and heterocyclic groups, e.g. pyridine or piperidine. Examples of groups which R³ may represent are methylene and ethylene. Examples of groups which R⁴ may represent are an alkyl group of 1-12 carbon atoms, preferably 1-6 carbon atoms, for example methyl, ethyl, propyl, butyl, hexyl, dodecyl, or benzyl or aryl groups, for example, phenyl. Examples of groups which R⁵ may represent are hydrogen or alkyl groups having up to 7, preferably up to 5, carbon atoms and their halo-, alkoxy- or phenyl- substituted derivatives; cycloalkyl groups, e.g. cyclohexyl, methylcyclohexyl, bornyl or isobornyl; aromatic groups, e.g. phenyl or substituted phenyl e.g. p-methyl-phenyl; or a heterocyclic group, e.g. pyridyl or piperidinyl. The aryl group Ar may, for example be a phenyl or napthyl group which may contain further alkyl or alkoxy substituents. A preferred embodiment of the present invention comprises hydrazides of the general formula: where R⁶ and R⁷ (which may be the same or different) each represents an aliphatic group of at least 2 carbon atoms or a cycloaliphatic group, R⁸ represents -(CH₂-) n - where n is an integer of 1 to 4, preferably 1 or 2, R⁹ represents a substituted or unsubstituted aliphatic group, Ar represents an aromatic group. Such hydrazides when used alone provide as good a result as previously obtained by a combination of hydrazides. The hydrazides of the present invention may be prepared by reacting an aryl hydrazide of the formula: with a carbodiimide of the formula: R¹-N = C = N - R² (IV) The hydrazide nucleating agents described herein are preferably present in the photographic elements and emulsions of this invention in a concentration of from 10⁻⁴ to 10⁻¹ mol per mol of silver. A preferred quantity of the hydrazide compound is from 5 x 10⁻⁴ to 5 x 10⁻² mol per mol of silver. Optimum results are obtained when the hydrzide compound is present in a concentration of from 8 x 10⁻⁴ to r x 10⁻³ mol per mol of silver. The hydrazide compound can be incorporated in a photographic silver halide emulsion layer or, alternatively, the hydrazide compound can be present in a hydrophilic colloid layer of the photographic element. Preferably, such hydrophilic colloid layer is coated contiguous to the emulsion layer in which the effects of the hydrzide compound are desired. The hydrazide compound can also be present in the photographic element in other layers such as subbing layers, interlayers or overcoating layers. The compounds of formula (III) may be prepared by known methods. For example, p-aminophenylacetic acid may be diazotised and the resulting diazo compound reduced with, for example, stannous chloride to form the corresponding hydrazine. Typically the reaction may be accomplished by stirring III and IV in a solvent, e.g. dimethylformamide, at room temperature. The silver halide emulsion may be any of the negative-working emulsions described in Research Disclosure, December 1978, Item 17643, Sections I and II published by Industrial Opportunities Ltd., The Old Harbourmaster's, 8 North Street, Emsworth, Hants P010 7DD, U.K. This publication will be identified hereafter as "Research Disclosure". The grains of the emulsions may be of any size and shape, for example the grains may be cubic, octahedral or tabular. Tabular grain emulsions are described, for example, in British specifications 2,109,576, 2,112,157 and 2,110,830. Suitable vehicles for the emulsion layers and other layers of elements of this invention are described in Research Disclosure Section IX and the publications cited therein. The photographic elements of this invention or individual layers thereof, can contain brighteners (see Research Disclosure Section V), antifoggants and stabilizers (see Research Disclosure Section VI), antistain agents and image dye stabilizer (see Research Disclosure Section VII, paragraphs I and J), light absorbing and scattering materials (see Research Disclosure Section VIII), hardeners (see Research Disclosure Section XI), plasticizers and lubricants (see Research Disclosure Section XII), antistatic agents (see Research Disclosure Section XIII), matting agents (see Research Disclosure Section XVI) and development modifiers (see Research Disclosure Section XXI). The photographic elements can be coated on a variety of supports as described in Research Disclosure Section XVII and the references described therein. The following examples illustrate the preparation and use of hydrazides according to the present invention. Example 1 Preparation of 1-formyl-2-{3-[2-(1,3-cyclohexylureido)carbonyl]ethyl-4-methoxyphenyl} hydrazine 3-[5-(2-formylhydrazino)-2-methoxyphenyl] propionic acid (2.38g, 0.01m) and dicyclohexyl carbodimide (4.12, 0.02m) in dry dimethylformamide (25ml) was stirred at room temperature for 12 hours. At the end of the reaction time the reaction mixture was filtered and the filtrate was poured onto ice/H₂O. The solid was filtered and purified by column chromatography to afford 63% of the required product. Example 2 (a) Control Coating A cubic bromoiodide emulsion (2.5 mole % iodide; mean grain size 0.23 µm) was coated on a polyester support at 3.5 g/m²Ag and 2.6 g/m² gelatin, and contained the spectral sensitizing dye anhydro-5,5'-dichloro-9-ethyl-3,3'-bis (3-sulphopropyl) oxocarbocyanine hydroxide, triethylamine salt at 216mg/Ag mole, the nucleating agents 1-formyl-2-{4[2,4-di-tert-pentylphenoxy -butyramido]phenyl} hydrazine (formula A below) at 373mg/Ag mole and 1-formyl-2-[4-(hexylureido)phenyl] hydrazine (formula B below) at 72mg/Ag mole; and the addenda oleic ether of polyethylene glycol-1540 at 250 mg/Ag mole, 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene sodium salt at 1g/Ag mole, a latex copolymer of methyl acrylate, 2-acrylamido-2-methylpropanesulphonic acid, sodium salt and 2-acetoacetoxy ethyl methacrylate (88:5:7 by weight) at 34g/Ag mole, 4-carboxymethyl-4-thiazoline-2-thione at 53mg/Ag mole, hydroquinone at 4.7g/Ag mole, and 4,5-dihydroxy-1,3-benzene disulphonic acid, disodium salt at 3.2g/Ag mole. The emulsion was overcoated with 1.3g/m² gelatin. The coating was hardened with bis(vinylsulphonylmethyl) ether at 4.9% of the total weight of gelatin. (b) Invention Prepared as described above (2a) except that the two nucleators were replaced with 400mg/Ag mole of 1-formyl-2-{3-[2-(1,3-dicyclohexylureido)carbonyl] ethyl-4-methoxyphenyl]hydrazine prepared in Example 1. The coatings were exposed through a 0.1 logE density step tablet for 10s to the light from a 6V 48W tungsten bulb suitably attenuated. Sensitometric data were determined after tray development for 80s at 30° C in fresh developer having the formula: Grams/l Sodium bromide 3.0 Orthophosphoric acid, 75% solution 47.4 Sodium metabisulfite 52.5 Sodium hydroxide 50% 50.0 5-Methylbenzotriazole 0.25 Hydroquinone 35.0 4-Hydroxymethyl-4-methyl-phenyl-3-pyrazolidinone 0.30 3-diethylamino-1,2-propanediol 19.7 Water to 1.0 liter Adjust with 50% Sodium hydroxide solution to pH 11.4 This data is shown in Table 1. Upper scale contrast is the gradient of a straight line drawn between the density points 2.5 and 4.0 above fog on the sensitometric curve. Coating Dmax Dmin Relative Speed Upper Scale Contrast 2a 5.30 0.02 100 9.8 2b 5.62 0.02 98 11.14 The results show that there is very little sensitometric difference between the two coatings. Image quality differences were also very small.

Claims: An aryl hydrazide having the formula: where X is SO₂ or CO, R¹ and R² (which may be the same or different) each represents an alkyl group having 2-12 carbon atoms, a cycloalkyl group, a phenyl, naphthyl, nitrophenyl, tolyl, pyridine or piperidine group; R³ represents -(CH₂-) n - where n is an integer of 1 to 4, preferably 1 or 2, R⁴ represents an alkyl group having 1-12 carbon atoms or a benzyl or phenyl group, R⁵ represents hydrogen or an alkyl group having up to seven carbon atoms, or a halo, alkoxy, or phenyl derivative, or a cycloalkyl, phenyl, methylphenyl pyridyl or piperidinyl group, provided that when X is SO₂, R⁵ is not hydrogen, Ar represents a phenyl or napthyl group which may contain alkyl or alkoxy groups in addition to R³ and OR⁴. An aryl hydrazide as claimed in Claim 1 in which the group -OR⁴ is ortho or para to the hydrazide group. An aryl hydrazide as claimed in Claim 1 or 2 in which the group -R³ is meta to the hydrazide group. An aryl hydrazide as claimed in Claim 1 having the general formula: where R⁶ and R⁷ (which may be the same or different) each represents an alkyl group having 2-12 carbon atoms or a cycloalkyl group, R⁸ represents -(CH₂-) n - where n is an integer of 1 to 4, preferably 1 or 2, R⁹ represents an alkyl group having 1-12 carbon atoms, Ar represents a phenyl or naphthyl group. The aryl hydrazide 1-formyl-2-{3-[2-(1,3-cyclohexylureido)carbonyl]ethyl-4-methoxyphenyl} hydrazine A photographic element comprising a support and a layer of a photosensitive silver halide emulsion containing as nucleating agent in or adjacent said layer an aryl hydrazide of formula where X is SO₂ or CO, R¹ and R² (which may be the same or different) each represents an aliphatic group of at least 2 carbon atoms, a cycloaliphatic group, a substituted or unsubstituted aromatic group or a substituted or unsubstituted heterocyclic group; R³ represents -(CH₂-) n - where n is an integer of 1 to 4, preferably 1 or 2, R⁴ represents a substituted or unsubstituted aliphatic or a substituted or unsubstituted aromatic group, R⁵ represents hydrogen or an aliphatic, aromatic or heterocyclic group any of which groups being substituted or unsubstituted, provided that when X is SO₂, R⁵ is not hydrogen, Ar represents an aromatic group which may contain alkyl or alkoxy groups in addition to R³ and OR⁴. A photographic element as claimed in Claim 6 which is a negative-working high contrast material. A method of forming photographic high contrast images which comprises imagewise exposing a photographic element according to Claims 6 or 7 and developing at a pH of from 10.5 to 12.0.

Inventors: COLDRICK PHILIP JOHN, SIDHU JASBIR, COLDRICK, PHILIP JOHN, SIDHU, JASBIR
Applicants: EASTMAN KODAK CO, KODAK LTD, EASTMAN KODAK COMPANY (A NEW JERSEY CORPORATION), KODAK LIMITED
Application year: 1988
Main classification: C07C243
IPC codes: G03C1, C07C243