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
  • G03C1/295—Development accelerators
• • 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
  • G03C1/485—Direct positive emulsions
  • G03C1/48538—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure
• • 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
• • 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
  • G03C1/061—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
  • 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
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/485—Direct positive emulsions
  • G03C1/48538—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure
  • G03C1/48546—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure characterised by the nucleating/fogging agent
  • G03C1/48561—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure characterised by the nucleating/fogging agent 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
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/485—Direct positive emulsions
  • G03C1/48538—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure
  • G03C1/48569—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure characterised by the emulsion type/grain forms, e.g. tabular grain emulsions
  • G03C1/48576—Direct positive emulsions non-prefogged, i.e. fogged after imagewise exposure characterised by the emulsion type/grain forms, e.g. tabular grain emulsions core-shell grain emulsions
• • 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
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
  • G03C2001/03535—Core-shell grains
• • 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
  • G03C2200/00—Details
  • G03C2200/34—Hydroquinone

Definitions

• the present invention relates to a method of making direct-positive images by development in the presence of a development nucleator of photographic light-sensitive silver halide elements, said images having a satisfactory maximum density even when exhaustion of the hydroquinone surface-type developer is in progress.
• a photographic method according to which a positive image is made without the use of a negative image or an intermediary process producing a negative image, is called a direct-positive method.
• a photographic light-sensitive element and a photographic emulsion for use according to such photographic method are called direct-positive element and direct-positive emulsion respectively.
• a variety of direct-positive photographic methods are known.
• the most useful methods are the method, which comprises exposing prefogged silver halide grains to light in the presence of internal or external electron acceptors and developing them, and the method, which comprises subjecting a silver halide emulsion containing silver halide grains that have light-sensitive specks mainly inside the grains to an image-wise exposure and developing the exposed emulsion in the presence of a development nucleator.
• the present invention relates to the latter method.
• a silver halide emulsion comprising light-sensitive specks mainly inside the grains and which forms latent images mainly inside the grains is referred to as internal latent image-type silver halide emulsion, and thus is distinguished from silver halide grains that form latent images mainly at the surface of the grains.
• the development nucleator may be incorporated into a developer, but it is usually incorporated into the photographic emulsion layer or in another layer of the photographic light-sensitive element.
• Development nucleators that can be used in the above-described method for making a direct-positive image include hydrazine and derivatives thereof as described in i.a. "Zeitschrift fürticianliche Photographie” by Arens, vol. 48, (1953) p.48, DD-A 5024, DE-A 3,021,423, in US-A 2,563,785, 2,588,982, 3,227,552, 4,245,037, 4,374,923, 4,540,655 , in Research Disclosure 23,510, p. 346-348, in EP-A 416,174, and in PCT/EP 90/01433 and the literature referred to in these documents.
• EP-A 416,174 the use of density-increasing amounts of a compound chosen from the class consisting of formic acid, oxalic acid, glyoxylic acid, or salts thereof and/or of a compound chosen from the class consisting of polyethylene glycols is recommended for addition to the photographic element and/or the developer.
• the level of Dmax obtained by developing an image-wise exposed light-sensitive silver halide element comprising at least one internal latent image-type silver halide emulsion layer in the presence of at least one development nucleator with a fresh hydroquinone surface-type developer comprising 10 to 50 g of hydroquinone per litre is maintained substantially even when exhaustion of the developer is in progress owing to oxidation products generated by aerial oxidation and/or multiple development work.
• the organic non-aromatic onium salt should be present during development of the exposed photographic element and can be incorporated for that purpose into e.g. the light-sensitive silver halide emulsion layer or into a hydrophilic colloid layer in water-permeable relationship therewith or alternatively it can be incorporated into the developer bath or into a separate bath. Mixtures of two or more organic non-aromatic onium salts can be used as well.
• Suitable organic non-aromatic onium salts are i.a. ammonium, sulphonium, and phosphonium salts, the cation of which carries covalently linked aliphatic and/or alicyclic hydrocarbon groups.
• Suitable representatives are e.g. trimethylsulfonium iodide and tetramethylphosphonium iodide.
• Preferred organic non-aromatic onium salts are the quaternary ammonium salts and in particular the tetraalkylated ammonium salts.
• Especially preferred tetra-alkylated ammonium salts are the tetra-alkylated ammonium halides e.g. tetra-n-butylammonium bromide.
• the organic non-aromatic onium salt may be added to the light-sensitive silver halide emulsion layer or to a hydrophilic colloid layer in water-permeable relationship therewith in an amount ranging from 0.01 g to 100 g per mol of silver halide.
• the organic non-aromatic onium salt may also be added to the hydroquinone surface-type developer in an amount ranging from 0.2 to 5 g of organic non-aromatic onium salt per 1.
• the development nucleators may be any of the compounds known for that purpose. Suitable development nucleators are i.a. : sulphur compounds e.g. thiourea dioxide, phosphonium salts e.g. tetra(hydroxymethyl)phosphonium chloride, hydroxylamine, bis-(p-aminoethyl)-sulphide and water-soluble salts thereof, reductic acid and derivatives thereof e.g.
• nucleating amounts of the development nucleators are present during development of the photographic element and can be incorporated for that purpose e.g. into the light-sensitive silver halide emulsion layer or into a hydrophilic colloid layer in water-permeable relationship therewith. Alternatively, they can also be added to the developing bath or to a separate bath.
• the development nucleators When used in the silver halide emulsion layer the development nucleators are present in a concentration of 10 ⁇ 4 mol to 10 ⁇ 1 mol per mol of silver halide.
• the development nucleator(s) Prior to the coating of the composition that will form the photographic layer comprising at least one development nucleator, the development nucleator(s) can be dissolved in an organic solvent and added to said composition. For instance, 1.3 x 10 ⁇ 3 mol of the development nucleator is added in the form of a 3.0 % solution in methanol per mol of silver.
• the development nucleator(s), preferably of the hydrazine-type can be added in dispersed form to the hydrophilic colloid composition that will form said emulsion layer or said hydrophilic colloid layer.
• these hydrazines are present in dispersed form in a hydrophilic colloid layer, preferably in the internal latent image-type silver halide emulsion layer, the direct-positive images obtained upon development have a very fine grain.
• the development nucleator(s) can be incorporated into the hydrophilic colloid composition that will form said emulsion layer or said hydrophilic colloid layer by dissolving them first in at least one water-immiscible, oil-type solvent or oil-former, adding the resulting solution to an aqueous phase containing a hydrophilic colloid, preferably gelatin, and a dispersing agent, passing the mixture through a homogenizing apparatus so that a dispersion of the oily solution in an aqueous medium is formed, mixing the dispersion with a hydrophilic colloid composition e.g.
• a gelatin silver halide emulsion and coating the resulting composition in the usual manner to produce a system in which particles of development nucleator(s), surrounded by an oily membrane, are distributed throughout the gel matrix.
• the dissolution of the development nucleator(s) in the oil-former may be facilitated by the use of an auxiliary low-boiling water-immiscible solvent, which is removed afterwards by evaporation.
• the development nucleator(s) can be dispersed in hydrophilic colloid compositions with the aid of at least one known oil-former e.g. an alkyl ester of phthalic acid.
• the oil-formers can be used in widely varying concentrations e.g. in amounts ranging from about 0.1 to about 10 parts by weight and preferably from 0.5 to 2 parts by weight relative to the amount of the development nucleator(s) dispersed therewith.
• oil-former with at least one auxiliary solvent that is insoluble or almost insoluble in water and has a boiling point of at most 150°C, such as a lower alkyl acetate e.g. ethyl acetate.
• the development nucleator(s) be incorporated into at least one internal latent image-type silver halide emulsion layer.
• the development nucleator(s) can also be incorporated into a hydrophilic colloid layer that stands in water-permeable relationship with an internal latent image-type silver halide emulsion layer.
• a hydrophilic colloid layer can be any layer that makes part of the direct-positive photographic light-sensitive element according to the present invention. It can thus be i.a. a light-sensitive layer, an intermediate layer, a filter layer, a protective layer, an antihalation layer, an antistress layer, a subbing layer, or any other layer. In other words, any layer will do provided the development nucleator(s) is not prevented from diffusing to the internal latent image-type silver halide emulsion layer.
• the development nucleator(s) used according to the present invention preferably is (are) incorporated into the layer(s) in an amount as mentioned above that yields satisfactory maximum density values of e.g. at least 1.50 when the internal latent image-type emulsion is developed with a surface-developer.
• the development nucleator(s) is(are) incorporated into a hydrophilic colloid layer that stands in water-permeable relationship with the internal latent image-type silver halide emulsion layer, it is adequate to incorporate the development nucleator(s) in the above amounts while taking into account the amount of silver contained in the associated internal latent image-type emulsion layer.
• An internal latent image-type silver halide emulsion is an emulsion, the maximum density of which obtained when developing it with an "internal type” developer exceeds the maximum density that is achievable when developing it with a "surface-type” developer.
• the internal latent image-type emulsions that are suited for use in accordance with the present invention yield a maximum density that, when these emulsions have been coated on a transparent support and are exposed to light for a fixed time of from 1/100 to 1 s and then developed for 3 min at 20°C with the internal-type Developer A as described hereinafter, is higher by at least 5 times than the maximum density obtained when the silver halide emulsion exposed as described above is developed for 4 min at 20°C with the surface-type Developer B as described hereinafter.
• Internal latent image-type silver halide emulsions that are suited for use in the method of the present invention generally are emulsions that have not been prefogged or only slightly so and have not been ripened chemically or only slightly so, e.g. as described in US-P 3,761,276 and 3,850,637.
• the photographic emulsions can be prepared according to different methods as described e.g. by P. Glafkides in “Chimie et Physique Photographique”, Paul Montel, Paris (1967), by G.F. Duffin in “Photographic Emulsion Chemistry", The Focal Press, London (1966), and by V.L. Zelikman et al in “Making and Coating Photographic Emulsion", The Focal Press, London (1966).
• the photographic silver halide emulsions used in the method of the present invention can be prepared by mixing the halide and silver solutions in partially or fully controlled conditions of temperature, concentrations, sequence of addition, and rates of addition.
• the silver halide can be precipitated according to the single-jet method, the double-jet method, or the conversion method.
• the conversion method has proved to be particularly suitable. According to this method a more soluble silver halide is converted into a less soluble silver halide.
• a silver chloride emulsion is converted in the presence of water-soluble bromide and possibly iodide, the amounts of which are selected with regard to the finally required composition, into a silver chlorobromoiodide or a silver bromoiodide emulsion.
• This conversion is preferably carried out very slowly in several consecutive steps i.e. by converting a part of the more soluble silver halide at a time.
• Another technique by which emulsions with an increased internal latent image sensitivity can be prepared has been described in GB-A 1,011,062.
• the silver halide particles of the photographic emulsions used in the method of the present invention may have a regular crystalline form such as a cubic or octahedral form or they may have a transition form. They may also have an irregular crystalline form such as a spherical form or a tabular form, or may otherwise have a composite crystal form comprising a mixture of said regular and irregular crystalline forms.
• the silver halide grains may have a multilayered grain structure.
• the grains may comprise a core and a shell, which may have different halide compositions and/or may have undergone different modifications such as the addition of dopes.
• the silver halide grains may also comprise different phases inbetween so that electron trapping systems can be obtained through the presence of phase boundaries in the so-called "core-shell" emulsion type.
• Two or more types of silver halide emulsions that have been prepared differently can be mixed for forming a photographic emulsion for use in the method of the present invention.
• the average size of the silver halide grains may range from 0.1 to 2.0 ⁇ m, preferably from 0.3 to 0.8 ⁇ m.
• the size distribution of the silver halide particles of the photographic emulsions used in the method of the present invention can be homodisperse or heterodisperse.
• a homodisperse size distribution is obtained when 95% of the grains have a size that does not deviate more than 30% from the average grain size.
• the emulsions may also comprise organic silver salts such as e.g. silver benzotriazolate and silver behenate.
• the silver halide crystals can be doped with Rh3+, Ir4+, Cd2+, Zn2+, Pb2+.
• the photographic emulsions may comprise substances that will provide iodide and/or bromide ions (in excess of any such ions provided by the light-sensitive emulsion itself) during the development of the exposed emulsions.
• Such compounds and the method using them have been described in GB-A 1,195,837.
• the emulsion can be left unwashed or it can be desalted in the usual ways e.g. by dialysis, by flocculation and re-dispersing, or by ultrafiltration.
• the light-sensitive silver halide emulsion used in the method of the present invention has not been sensitized chemically. However, it may have been chemically sensitized or prefogged. Chemical sensitization can be performed as described i.a. in the above-mentioned “Chimie et Physique Photographique” by P. Glafkides, in the above-mentioned “Photographic Emulsion Chemistry” by G.F. Duffin, in the above-mentioned “Making and Coating Photographic Emulsion” by V.L. Zelikman et al, and in "Die Grundlagen der Photographischen mit Silberhalogeniden” edited by H. Frieser and published by Akademische Verlagsgesellschaft (1968).
• chemical sensitization can be carried out by effecting the ripening in the presence of small amounts of compounds containing sulphur e.g. thiosulphate, thiocyanate, thioureas, sulphites, mercapto compounds, and rhodamines.
• sulphur e.g. thiosulphate, thiocyanate, thioureas, sulphites, mercapto compounds, and rhodamines.
• the emulsions can be sensitized also by means of gold-sulphur ripeners or by means of reductors e.g. tin compounds as described in GB-A 789,823, amines, hydrazine derivatives, formamidine-sulphinic acids, and silane compounds.
• Chemical sensitization can also be performed with small amounts of Ir, Rh, Ru, Pb, Cd, Hg, Tl, Pd, Pt, or Au.
• One of these chemical sensitization methods or a combination thereof can be used.
• Chemical sensitization of core-shell type direct positive emulsions can be obtained through the chemical ripening of the AgX-core, followed by a shell-type silver halide precipitation. After completing the precipitation of the shell, the surface of the silver halide grains can be chemically sensitized in accordance with the procedures mentioned before.
• the spectral photosensitivity of the silver halide can be adjusted by proper sensitization to any desired spectral range comprised between 300 and 900 nm e.g. to blue light, to green light, to red light, to infrared light, by means of the usual mono- or polymethine dyes such as acidic or basic cyanines, hemicyanines, oxonols, hemioxonols, styryl dyes or others, also tri- or polynuclear methine dyes e.g. rhodacyanines or neocyanines.
• Such spectral sensitizers have been described by e.g. F.M.
• the spectral photosensitivity of the silver halide can also be adjusted for exposure by laser light e.g. helium-neon laser light, argon laser light, and solid state laser light. Dyes that can be used for adjusting the photosensitivity to laser light have been described in i.a.
• the silver halide can also be sensitized with dyes providing a spectral sensitivity mainly in the range of 400 to 540 nm and not extending the sensitivity substantially beyond 540 nm so that the resulting photosensitive element can be handled in safelight conditions prior to the image-wise exposure.
• dyes providing a spectral sensitivity mainly in the range of 400 to 540 nm and not extending the sensitivity substantially beyond 540 nm so that the resulting photosensitive element can be handled in safelight conditions prior to the image-wise exposure.
• Suitable dyes that can be used for that purpose have been described in e.g. US-P 4,686,170.
• a particular effect of gradation enhancement can be obtained by using at least one merocyanine dye; if desired, in combination with at least one rhodacyanine dye.
• these dyes need not necessarily absorb in the wavelength range of the exposure light.
• the sensitizing dyes employed in the present invention are used in a concentration almost equivalent to that used in ordinary negative silver halide emulsions.
• the sensitizing dyes be employed in a dye concentration to a degree that does not substantially cause desensitization in the region of intrinsic sensitivity of the silver halide emulsion.
• the sensitizing dyes be employed in a concentration of from about 1.0x10 ⁇ 5 to about 5x10 ⁇ 4 mol per mol of silver halide, and particularly in a concentration of from about 4x10 ⁇ 5 to 2x10 ⁇ 4 mol per mol of silver halide.
• Suitable supersensitizers are i.a. heterocyclic mercapto compounds containing at least one electronegative substituent as described e.g. in US-P 3,457,078, nitrogen-containing heterocyclic ring-substituted aminostilbene compounds as described e.g. in US-P 2,933,390 and 3,635,721, aromatic organic acid/formaldehyde condensation products as described e.g. in US-P 3,743,510, cadmium salts, and azaindene compounds.
• the substituted phenol derivative is 5-sulfosalicylic acid.
• the phenol derivative may be added to the developer in amounts of from 0.02 to 1.00 mole/l, preferably from 0.02 to 0.5 mole/l.
• the processing method of the present invention basically includes a development step and a fixing step.
• a stopping step and a rinsing step can be included as well, if desired.
• the processing temperature is usually selected within the range of from 18°C to 50°C. However, temperatures lower than 18°C and temperatures higher than 50°C can be employed, if desired.
• the processing time may vary within broad ranges provided the mechanical strength of the elements to be processed is not adversely influenced and no decomposition takes place. As is generally known sensitometric results obtained can strongly depend on the temperature of the developer. A more important independence of the sensitometry from development conditions can be demonstrated in the presence of density-stabilizing amounts of organic non-aromatic onium salt.
• the pH of the developer usually has a value ranging from 10.5 to 14, preferably from 11.5 to 12.5.
• the hydroquinone-type developer used for developing an exposed photographic element in accordance with the present invention need not comprise an alkanolamine, but may incorporate a primary, secondary, or tertiary alkanolamine e.g. triisopropanolamine.
• a hydroquinone alone or a combination of a hydroquinone with a secondary developing agent of the class of 1-phenyl-3-pyrazolidinone compounds and p-N-methyl-aminophenol can be used as developing agent.
• hydroquinones include hydroquinone, methylhydroquinone, t-butyl-hydroquinone, chlorohydroquinone, and bromohydroquinone.
• the amount of the hydroquinone used is not limited,but the previously mentioned stabilizing effect on the sensitometry after developer exhaustion is also observed when the developer is containing less than 25 g of hydroquinone.
• Particularly useful 1-phenyl-3-pyrazolidinone developing agents that can be used in combination with a hydroquinone are 1-phenyl-3-pyrazolidinone, 1-phenyl-4-methyl-3-pyrazolidinone, 1-phenyl-4-ethyl-5-methyl-3-pyrazolidinone, and 1-phenyl-4,4-dimethyl-3-pyrazolidinone.
• N-methyl-p-aminophenol and 2,4-diaminophenol can be used in combination with a hydroquinone as a developing agent.
• the secondary developing agent used in the processing method of the present invention is one of the class of the 1-phenyl-3- pyrazolidinone compounds it is preferably present in an amount of 2 to 20 g per litre.
• the secondary developing agent is p-N-methyl-aminophenol it is preferably present in an amount of 1 to 40 g per litre.
• the developer comprises a preservative such as a sulphite e.g. sodium sulphite in an amount ranging from 45 g to 160 g per litre.
• a preservative such as a sulphite e.g. sodium sulphite in an amount ranging from 45 g to 160 g per litre.
• the developer comprises such alkali-providing substances like hydroxides of sodium and potassium, alkali metal salts of phosphoric acid and/or silicic acid e.g. trisodium phosphate, orthosilicates, metasilicates, hydrodisilicates of sodium or potassium, and sodium carbonate.
• alkali-providing substances can be substituted in part or wholly by alkanolamines.
• the developer may comprise a buffering agent such as a carbonate e.g. sodium carbonate, potassium carbonate, trisodium phosphate, and sodium metaborate.
• a buffering agent such as a carbonate e.g. sodium carbonate, potassium carbonate, trisodium phosphate, and sodium metaborate.
• the developer may further contain an inorganic anti-fogging agent such as a bromide e.g. potassium bromide and/or an organic anti-fogging agent such as a benzimidazole e.g. 5-nitro-benzimidazole, a benzotriazole like benzotriazole itself and 5-methyl-benzotriazole.
• an inorganic anti-fogging agent such as a bromide e.g. potassium bromide and/or an organic anti-fogging agent such as a benzimidazole e.g. 5-nitro-benzimidazole, a benzotriazole like benzotriazole itself and 5-methyl-benzotriazole.
• the developer may contain other ingredients such as i.a. toning agents, development accelerators, oxidation preservatives, surface-active agents, defoaming agents, water-softeners, anti-sludge agents, hardeners including latent hardeners, and viscosity-adjusting agents.
• ingredients such as i.a. toning agents, development accelerators, oxidation preservatives, surface-active agents, defoaming agents, water-softeners, anti-sludge agents, hardeners including latent hardeners, and viscosity-adjusting agents.
• aqueous solution having a low pH An aqueous solution having a pH not higher than 3.5 comprising e.g. acetic acid and sulphuric acid, and containing a buffering agent is preferred.
• Buffered stop bath compositions comprising a mixture of sodium dihydrogen orthophosphate and disodium hydrogen orthophosphate are preferred.
• fixing solutions may be used.
• useful fixing agents include organic sulphur compounds known as fixing agents, as well as a thiosulphate, a thiocyanate, etc.
• the fixing solution may contain a water-soluble aluminium salt as a hardening agent.
• the photographic light-sensitive silver halide element for use in the method of the present invention comprises an internal latent image-type silver halide emulsion layer, which preferably is a gelatin silver halide emulsion layer.
• an internal latent image-type silver halide emulsion layer which preferably is a gelatin silver halide emulsion layer.
• gelatin instead of gelatin or in admixture with gelatin a variety of other hydrophilic colloids can be used as the binder for the silver halide.
• hydrophilic colloids that can be used as the binder for the silver halide are synthetic, semi-synthetic, or natural polymers.
• Synthetic substitutes for gelatin are e.g. polyvinyl alcohol, poly-N-vinyl pyrrolidone, polyvinyl imidazole, polyvinyl pyrazole, polyacrylamide, polyacrylic acid, and derivatives thereof, in particular copolymers thereof.
• Other synthetic substitutes for gelatin are latices such as a latex of poly(ethyl acrylate).
• Natural substitutes for gelatin are e.g. other proteins such as zein, albumin and casein, cellulose derivatives, saccharides, starch, and alginates.
• the semi-synthetic substitutes for gelatin are modified natural products e.g. gelatin derivatives obtained by conversion of gelatin with alkylating or acylating agents or by grafting of polymerizable monomers on gelatin, and cellulose derivatives such as hydroxyalkyl cellulose, carboxymethyl cellulose, phthaloyl cellulose, and cellulose sulphates.
• modified natural products e.g. gelatin derivatives obtained by conversion of gelatin with alkylating or acylating agents or by grafting of polymerizable monomers on gelatin
• cellulose derivatives such as hydroxyalkyl cellulose, carboxymethyl cellulose, phthaloyl cellulose, and cellulose sulphates.
• binders often has a favourable photographic effect on the formation of the direct-positive image.
• the addition of polyvinyl pyrrolidone and of said latex of poly(ethyl acrylate) often increases the maximum density of the direct-positive image.
• Suitable additives for improving the dimensional stability of the photographic element can also be incorporated together with the hydrophilic colloid.
• Suitable examples of this type of compounds include i.a. dispersions of a water-soluble or hardly soluble synthetic polymer e.g.
• the binder should dispose of an acceptably high number of functional groups, which by reaction with an appropriate hardening agent can provide a sufficiently resistant layer.
• functional groups are especially the amino groups, but also carboxylic groups, hydroxy groups, and active methylene groups.
• the gelatin can be lime-treated or acid-treated gelatin.
• the preparation of such gelatin types has been described in e.g. "The Science and Technology of Gelatin", edited by A.G. Ward and A. Courts, Academic Press 1977, page 295 and next pages.
• the gelatin can also be an enzyme-treated gelatin as described in Bull. Soc. Sci. Phot. Japan, N° 16, page 30 (1966).
• Suitable stabilizers are azaindenes, preferably tetra- or penta-azaindenes, especially those substituted with hydroxy or amino groups e.g. 4-hydroxy-6-methyl-1,3,3a,7-tetra-azaindene. Compounds of this kind have been described by Birr in Z. Wiss. Photogr. Photophys.
• stabilizers are i.a. heterocyclic mercapto compounds e.g. 1-phenyl-5-mercaptotetrazole, 3-methyl-benzothiazole, quaternary benzothiazole derivatives, benzotriazole.
• Specific examples of stabilizers have been mentioned by K. Mees in The Theory of the Photographic Process, 3rd ed. 1966 by reference to the papers that first reported such compounds, and in addition, have been described in i.a.
• the silver halide emulsions may comprise other ingredients e.g. development accelerators, wetting agents, and hardeners.
• the binder of the silver halide emulsion layer and/or of other hydrophilic colloid layers can, especially when the binder used is gelatin, be hardened with appropriate hardening agents such as those of the epoxide type, those of the ethylenimine type, those of the vinylsulfone type e.g. 1,3-vinyl-sulphonyl-2-propanol, chromium salts e.g. chromium acetate and chromium alum, aldehydes e.g.
• N-methylol compounds e.g. dimethylolurea and methyloldimethylhydantoin
• dioxan derivatives e.g. 2,3-dihydroxy-dioxan
• active vinyl compounds e.g. 1,3-,5-triacryloyl-hexahydro-s-triazine
• active halogen compounds e.g. 2,4-dichloro-6-hydroxy-s-triazine
• mucohalogenic acids e.g. mucochloric acid and mucophenoxychloric acid.
• the binders can also be hardened with fast-reacting hardeners such as carbamoylpyridinium salts and the phosphorus compounds described in EP Application N° 89201865.6, which corresponds to the US Serial N° .
• iodine ions e.g. potassium iodide
• the developer used in the method of the present invention may also contain iodine ions.
• the photographic light-sensitive element used in the method of the present invention may contain a water-soluble dye in a hydrophilic colloid layer as a filter dye or for other various purposes such as for the prevention of irradiation or anti-halation.
• a water-soluble dye in a hydrophilic colloid layer as a filter dye or for other various purposes such as for the prevention of irradiation or anti-halation.
• Such dyes include oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, cyanine dyes, and azo dyes. Of these, oxonol dyes, hemioxonol dyes, and merocyanine dyes are useful.
• hydrophilic colloid layer of the photographic light-sensitive element used in the method of the present invention contains a dye or an UV-absorbing agent
• these compounds may be mordanted by means of a cationic polymer e.g. polymers described in GB-A 1,468,460 and 685,475, US-P 2,675,316, 2,839,401, 2,882,156, 3,048,487, 3,184,309, 3,445,231, and 3,986,875, DE-A 1,914,362.
• the photographic light-sensitive element for use in the method of the present invention may comprise various kinds of surface-active agents in the photographic emulsion layer or in at least one other hydrophilic colloid layer.
• Surface-active agents can be used for various purposes e.g. as coating aids, as compounds preventing electric charges, as compounds improving slidability, as compounds facilitating dispersive emulsification, as compounds preventing or reducing adhesion, and as compounds improving the photographic characteristics e.g higher contrast, sensitization, and development acceleration.
• Development acceleration can be accomplished with the aid of various compounds, preferably polyalkylene derivatives having a molecular weight of at least 400 such as those described in e.g. US-P 3,038,805, 4,038,075, and 4,292,400.
• the photographic light-sensitive element for use in the method of the present invention may further comprise in the silver halide emulsion layer various other additives such as e.g. UV-absorbers, matting agents or spacing agents, lubricants, and plasticizers.
• various other additives such as e.g. UV-absorbers, matting agents or spacing agents, lubricants, and plasticizers.
• Suitable UV-absorbers are i.a. aryl-substituted benzotriazole compounds as described in US-P 3,533,794, 4-thiazolidone compounds as described in US-P 3,314,794 and 3,352,681, benzophenone compounds as described in JP-A 2784/71, cinnamic ester compounds as described in US-P 3,705,805 and 3,707,375, butadiene compounds as described in US-P 4,045,229, and benzoxazole compounds as described in US-P 3,700,455.
• Suitable spacing agents are e.g. finely divided silica particles and polymer beads as described US-P 4,614,708.
• the average particle size of spacing agents is comprised between 0.2 and 10 ⁇ m.
• Spacing agents can be soluble or insoluble in alkali. Alkali-insoluble spacing agents usually remain permanently in the photographic element, whereas alkali-soluble spacing agents usually are removed therefrom in an alkaline processing bath.
• Suitable spacing agents can be made i.a. of polymethyl methacrylate, of copolymers of acrylic acid and methyl methacrylate, and of hydroxypropylmethyl cellulose hexahydrophthalate. Other suitable spacing agents have been desribed in US-P 4,614,708.
• a matting agent and/or a lubricant may be added to an emulsion layer and/or a protective layer of the direct-positive photographic light-sensitive element used in the method of the present invention.
• Suitable matting agents are e.g. water-dispersible vinyl polymers such as poly(methyl methacrylate) having an appropriate particle size of from 0.2 to 6 ⁇ m and inorganic compounds e.g. silver halide and strontium barium sulphate.
• the lubricant is used to improve the slidability of the photographic element. Suitable examples of lubricants are e.g.
• liquid paraffin waxes such as esters of higher fatty acids, polyfluorinated hydrocarbons or derivatives thereof, silicones such as polyalkylpolysiloxanes, polyarylpolysiloxanes, polyalkylarylpolysiloxanes and alkyleneoxide addition derivatives thereof.
• a variety of photographic supports can be employed for the photographic light-sensitive element used in the method of the present invention.
• the silver halide emulsion can be coated onto one side or both sides of the support.
• the support may be transparent or non-transparent.
• Suitable supports are e.g. a baryta-coated paper, a resin-coated paper e.g. a polyolefin-coated paper, a synthetic paper, a cellulose triacetate film, a polyethylene terephthalate film or another plastic base or glass plate.
• a first step for making a direct-positive image the photographic light-sensitive silver halide element is exposed image-wise.
• This exposure can either be a high-intensity exposure such as a flash exposure or a normal intensity exposure such as a daylight exposure, a low-intensity exposure such as an exposure by means of a printer, or an exposure of even lower intensity.
• the light source used for the exposure should match the wavelength sensitivity of the light-sensitive element. Natural light (sunlight), the light emitted by an incandescent lamp, a halogen lamp, a mercury vapour lamp, a fluorescent tube, an electronic flash lamp, or by a metal-burning flash bulb can be used.
• Gas, dye or semiconductor lasers emitting light in the wavelength ranges from ultraviolet to infrared as well as a plasma light source are also suitable light sources for exposing the photographic light-sensitive silver halide element for use in the method of the present invention.
• a line-shaped light source or a planar light source as well as a microshatter arrangement with a fluorescing area (CRT, etc.), the fluorescence of which is produced by fluorescing substances stimulated by means of electron rays, or even a liquid-crystal display (LCD) or a lanthanum-doped lead-titanium zirconate can be used as well as light sources for exposing the photographic light-sensitive silver halide element for use in the method of the present invention.
• the spectral distribution of the exposure light can be controlled by means of a colour filter.
• the photographic light-sensitive silver halide element used in the method of the present invention may serve different purposes.
• Application fields, in which direct-positive images can be made in accordance with the present invention are i.a. graphic arts recording processes, silver salt diffusion transfer reversal processes, duplicating processes for cinematographic black-and-white negatives, infrared laser recording processes, X-ray recording processes, cathode-ray recording processes, fototype-setting processes, etc., particularly microfilm recording processes.
• An internal latent image-type direct-positive gelatin silver halide emulsion was prepared by conversion of a silver chloride emulsion in the presence of water-soluble bromide and iodide to form grains having a core of silver chloride (4 mol%) and a shell of silverbromoiodide (95/1 mol%).
• the average grain diameter was 0.4 ⁇ m.
• a 3% solution (in methanol) of the development nucleator 1-formyl-2-phenyl-hydrazine was made and added to the silver halide emulsion so that the hydrazine compound was present in an amount of 0.075 mol per mol of silver halide.
• the resulting emulsion was coated on a polyester support at a ratio of 0.035 mol of silver halide per m2 and dried.
• the "exhausted” developer contained the following ingredients : demineralized water 600 ml hydroquinone 10 g p-N-methyl-aminophenol 1.8 g 5-sulfosalicylic acid 100 g triisopropanolamine 27 sodium sulphite 76 g sodium bromide 5 g ethylenediamine tetraacetic acid 1.25 g 5-methyl-benzotriazole 0.36 g tetra-n-butylammonium bromide (TBAB) amount as specified in Table 1 demineralized water to make 1 l sodium hydroxide to a pH value of 12.1

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• 1992
  • 1992-12-22 EP EP92204047A patent/EP0603433A1/de not_active Withdrawn

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