Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/08—Sensitivity-increasing substances
  • G03C1/10—Organic substances
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/067—Additives for high contrast images, other than hydrazine compounds
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/29—Development processes or agents therefor
  • G03C5/305—Additives other than developers

Definitions

• This invention relates to negative-acting silver halide photographic materials and in particular to photographic elements comprising Group VIII metal doped silver halide emulsions associated with a speed and contrast promoting agent which are suitable for use in the photolithographic printing industry and for the development of daylight handleable contact film.
• Photosensitive silver halide materials are commonly used in the photolithographic industry to obtain half tone, dot or line, high contrast images.
• contrast promoting agents among which are the water soluble Group VIII metal salts, such as the trivalent salts of rhodium, ruthenium and iridium. It is known that good results as regards high covering power (which is the ratio between the maximum density obtained after development and the silver halide coverage) and rapid developability (for productivity increase) can be obtained by using fine grained (less than 0.15 ⁇ m) and high chloride content silver halide emulsions. It is known that such emulsions which contain a Group VIII metal as a contrast promoting agent may still not have the required contrast, and as the dopant desensitises the emulsion, it may not have the required speed.
• contrast promoting agents among which are the water soluble Group VIII metal salts, such as the trivalent salts of rhodium, ruthenium and iridium.
• British Patent No. 741228 discloses the use of 4-­substituted 3-amino-5-mercapto-4,1,2-triazoles of general formula (I) in which: R represents other than H, in photographic constructions.
• the compounds of formula (I) are said to restrain the formation of chemical fog without seriously affecting the speed, contrast or other properties of the emulsion.
• British Patent No. 2573027 discloses the use of compounds of general formulae (II) and (III) in which: X represents O or S, Y represents O, S or NH, and, D represents substituted or unsubstituted carbon atoms to complete a 6 membered ring, in a photographic construction as anti-bronzing agents.
• X represents O or S
• Y represents O, S or NH
• D represents substituted or unsubstituted carbon atoms to complete a 6 membered ring
• U.S. Patent No. 1,725,934 discloses the use of thiazole derivatives in silver halide constructions, but as an anti-fogging agent.
• a photographic element comprising a Group VIII metal doped negative-acting silver halide emulsion characterised in that the emulsion is associated with one or more speed and contrast promoting agents comprising a compound having a nucleus of one of the following general formulae (i) to (iv) in which:
• Each R1 independently represents a hydrogen atom or an alkyl group of 1 to 5 carbon atoms, optionally having one or more substituents selected from hydroxyl moieties, carboxyl moieties, alkoxy carbonyl groups of 1 to 5 carbon atoms, cyano moieties, halogen atoms, nitro moieties, amino moieties and aryl groups of up to 10 carbon atoms, wherein the aryl group may be optionally substituted with one or more substituents selected from alkyl groups of 1 to 5 carbon atoms, hydroxyl moieties, carboxyl moieties, alkoxy carbonyl groups of 1 to 5 carbon atoms
• R1 is preferably a hydrogen atom or a methyl group
• R2 is preferably a hydrogen atom or SH
• X1 is preferably N, -CH, -CCH3 or -CNO2
• R3 is preferably SH, SCH3 or NH2
• R4 is preferably hydrogen.
• the invention provides a negative-acting photosensitive silver halide material which may be used to obtain black and white half tone, line or dot images for photolithographic purposes.
• the element preferably comprises a support, having one or more hydrophilic colloidal layers located thereon, in which at least one layer comprises a fine grain, high chloride content and Group VIII metal doped photographic emulsion associated with one or more speed and contrast promoting agents selected from compounds of general formulae (i) to (iv).
• the speed and contrast promoting agents need not be present in the emulsion during imaging, but must be associated with the emulsion during development.
• the compounds of general formulae (i) to (iv) may be introduced in to the emulsion from a treatment bath or the developer solution.
• the compounds may be present in the photographic element during imaging and optionally additional compounds present in the developer solution.
• Examples of compounds suitable for inclusion as speed or contrast promoting agents are:
• the fine grain, high chloride content and Group VIII metal doped photographic emulsion is associated with one or more speed and contrast promoting agents selected from compounds A to E.
• the material After image wise exposure of the fine grain, high chloride content rhodium doped silver halide emulsion, the material undergoes a photographic processing step comprising an alkaline developing solution wherein the speed and contrast promoting agent is reactively associated with the emulsion.
• a photographic processing step comprising an alkaline developing solution wherein the speed and contrast promoting agent is reactively associated with the emulsion.
• the speed and contrast promoting agent in the developer solution followed by conventional washing or fixing but it is preferred that the agents are introduced as a precoating addition.
• fine grain is used in the context of the present invention to refer to silver halide grains having an average grain size of not more than 0.2 ⁇ m.
• High chloride content refers to the emulsion having at least 60% and preferably at least 80% of its total halide molar content consisting of chloride ions.
• the emulsion is preferably a chlorobromide emulsion wherein the remainder of the halide content comprises bromide ions and a most preferred emulsion comprises 84% silver chloride : 16% silver bromide having a mean silver halide grain size of 0.09 ⁇ m.
• Group VIII metal doped refers to the process whereby during precipitation or physical ripening of the silver halide emulsion, salts of one or more Group VIII metals, e.g., trisodium hexachlororhodate (III), disodium pentachlororuthenate (III) and tripotassium hexachloroiridate (III) are present in the solution.
• the preferred dopants are water-soluble trivalent salts of rhodium.
• the speed and contrast increasing effect of the compounds of general formulae (i) to (iv) is directly proportional to the level of dopant.
• the level of doping may be from 10 ⁇ 6 to 10 ⁇ 2 moles Group VIII metal salt per mole of silver but preferably is from 10 ⁇ 4 to 10 ⁇ 2 moles Group VIII metal salt per mole of silver and most preferably from 10 ⁇ 3 to 10 ⁇ 2 mole Group VIII metal salt per mole of silver.
• the amount of the speed and contrast promoting agent added is in the range 10 ⁇ 4 to 10 ⁇ 1 mole of agent per mole of silver halide but preferably in the range 10 ⁇ 2 to 5 x 10 ⁇ 2 mole of agent per mole of silver halide.
• a silver halide emulsion of 84 mole % chloride and 16 mole % bromide was prepared by the simultaneous addition under constant agitation of water solution B and water Solution C by the double jet technique over a period of 25 minutes to water gelatin Solution A.
• the compositions A to C were: Solution A Water 833.3g Gelatin 25g Polyvinylpyrrolidone (K-30) 6.33g KBr 0.167ml (1N) Solution B Water 368g AgNO3 170g Solution C Water 361.3g KCl 62.65g (0.84 moles) KBr 19.04g (0.16 moles) Na3RhCl6.12H2O 0.200g
• the water gelatin Solution A was kept at a constant temperature of 40°C.
• Solution B was added at a constant addition rate whilst the addition rate of Solution C was varied to maintain the potential of the emulsion thus formed at a value of 120 ⁇ 5mV (as measured with a specific electrode for Br ions and a reference electrode of the saturated Ag/AgC1 type).
• the emulsion so prepared following the removal of soluble salts by the conventional coagulation method, had a mean grain diameter of 0.09 ⁇ m.
• the emulsion was then chemically sensitised with sodium gold chloride and sodium thiosulphate. At the end of the chemical sensitisation a speed and contrast promoting agent selected from compounds A to J in a suitable solvent was added to the emulsion before preparation for coating with the addition of additional gelatin, coating surface active agents and formaldehyde hardener.
• the emulsion was coated at a silver coating weight of 2.7g Ag/m2 onto a polyester support base which was backed with a red antihalation layer.
• the resulting films were exposed through a 0-2, 20cm continuous wedge.
• the exposing lamp was a Violux 1500S UV lamp at a distance of 52 inches from the film plane.
• the exposed films were developed in 3M RDC TM developer for 20 seconds @ 40°C and fixed in 3M Fix Roll TM Fixer.
• Each of compounds A to F were dissolved in an appropriate solvent and added at varying levels as a precoating addition to the emulsion.
• the emulsion used had the composition described previously and had been chemically sensitised with conventional sulphur and gold compounds.
• no speed and contrast enhancing compound is added and with conventional exposure and processing the film shows little development, only on extremely long exposures to UV light does any density build up.
• the compounds of the invention are added, then a dramatic speed and contrast increase is seen.
• Example 2 An alternative to the emulsion composition described in Example 1 was tested with Compound A.
• the emulsion was made following the protocol described previously except the halide ratio was altered from 84 : 16 chloride to bromide to 96 : 4. Very similar results were observed with increases in both speed and contrast.
• digested emulsion composition as per Example 1
• the film was given the standard exposure and processed in RDC developer having some of compound A added. Washing and fixing were carried out in a conventional fashion.
• Emulsion 4 was found to be too fast to be exposed by the Violux UV lamp so exposure was conducted with a quartz lamp.
• Table 6 shows the increase in speed (logE) observed on chemical sensitisation when Compound A is added as a precoating addition or not added at all. It can be seen that with no Compound A present, digestion gives a greater increase in speed with increasing levels of rhodium dopant, when Compound A is added as a final the effect of chemical sensitisation decreases with increasing rhodium dopant level i.e. at higher rhodium levels most of the speed increase comes from the addition of Compound A, the digestion step only gives a small further speed increase.
• Example 2 An emulsion similar to that in Example 1 was prepared except that the halide ratio was adjusted so that it was 96 mole % chloride 4% bromide emulsion. Seven emulsions were prepared with the following levels of Group VIII transition metal dopants.
• Example 2 Once prepared the emulsion was washed and chemically sensitised in the same way as in Example 1. Compound A was then added at a level of 1.95g per mole of silver. The emulsion was then coated onto clear subbed polyester with the conventional coating aids and hardeners at a coating weight of 2.5g Ag/m2.
• the resulting films were exposed through a 0-4 10cm continuous wedge.
• the exposing source was a Thiemer Spektra Proof Daylight containing a 1KW Th1007 polymer bulb.
• the exposed films were developed in 3M RDC developer for 30 seconds at 35°C and fixed in 3M Fix Roll fixer.
• Emulsions 4 and 5 improvements in speed and, especially, contrast and maximum density are again obtained on addition of Compound A.
• Emulsions 6 and 7 show the effect of iridium doping. There is an overall desensitisation related to the level of dopant (see li) 6i) and 7i). On addition of Compound A speed, contrast and for the heavily doped emulsion maximum density are increased. For Emulsion 7 solarisation is also observed which is eliminated on addition of Compound A.

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• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (2)

Publications (3)

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• 1989
  • 1989-05-18 GB GB898911453A patent/GB8911453D0/en active Pending
• 1990
  • 1990-05-02 AU AU54632/90A patent/AU624946B2/en not_active Ceased
  • 1990-05-10 CA CA 2016495 patent/CA2016495A1/en not_active Abandoned
  • 1990-05-11 EP EP90305114A patent/EP0398600B1/de not_active Expired - Lifetime
  • 1990-05-11 DE DE1990628801 patent/DE69028801T2/de not_active Expired - Fee Related
  • 1990-05-17 JP JP12809990A patent/JPH036551A/ja active Pending

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