Identified Desensitizer Or Electron Acceptor Containing Patents (Class 430/597)
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Patent number: 6974663Abstract: A photographic element is described comprising a support bearing one or more hydrophilic colloid layers including at least one photographic silver halide emulsion layer, wherein a photographically useful compound is incorporated into at least one hydrophilic colloid layer in the form of an intercalation composition comprising a layered host material having molecules of the photographically useful compound inserted as guest molecules between the layers of the host material. The invention provide novels materials and a method of incorporating active chemistry compounds such as developers or development inhibitors directly into a photographic imaging element with improved stability and keeping response versus known methods for incorporating active chemistry compounds.Type: GrantFiled: December 21, 2001Date of Patent: December 13, 2005Assignee: Eastman Kodak CompanyInventors: Joseph F. Bringley, Krishnamohan Sharma, Kenneth J. Lushington
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Patent number: 6479230Abstract: A silver halide photographic light-sensitive emulsion containing, at a ratio of 50% or more of the total projected area of silver halide grains, tabular silver halide grains each having faces as parallel major faces and an aspect ratio of 2 or more and including 10 or more dislocation lines per grain, and containing at least one compound represented by formula (1) or (2) below: wherein A represents an atomic group required to form a nitrogen-containing hetero ring, each of B and E independently represents a divalent group containing at least one divalent group selected from the group consisting of alkylene, arylene, —O—, —S—, —SO2—, —CO2—, and —N(R5)-, wherein R5 represents a hydrogen atom, an alkyl group, or an aryl group, provided that each of —O—, —S—, —SO2—, —CO2—, and —N(R5)- is adjacent to and connects with alkylene or arylene, and that B does not bond to the nitrogen atom whichType: GrantFiled: February 25, 2000Date of Patent: November 12, 2002Assignee: Fuji Photo Film Co., Ltd.Inventor: Kiyoshi Morimoto
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Patent number: 6033833Abstract: A new fogging photographic processing solution for a reversal process comprises a compound (I) and a bi-nucleophilic agent. Compound (I) corresponds to the following formula: ##STR1## wherein A is a group capable of being adsorbed to the silver halide surface, L is a linking group and r is 0 or 1, R.sub.1 and R.sub.2 are independently selected from an alkyl group, substituted or unsubstituted, and an aryl group substituted or unsubstituted. A process of producing a positive image by imagewise exposure of a reversal silver halide material comprises contacting the material with the above fogging solution or by imagewise exposure of such a material containing a compound (I) and contacting the material with a solution comprising a bi-nucleophilic agent.Type: GrantFiled: April 29, 1999Date of Patent: March 7, 2000Assignee: Eastman Kodak CompanyInventors: Siu C. Tsoi, Peter J. Twist, David T. Southby
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Patent number: 5874207Abstract: A direct-positive silver halide light-sensitive material comprising a support having thereon at least one pre-fogged light-sensitive silver halide emulsion layer, wherein the light-sensitive material comprises a specific onium salt compound in the emulsion layer or a hydrophilic protective colloid layer adjacent thereto. Also disclosed is a method of preparing a pre-fogged light-sensitive silver halide emulsion for use in the light-sensitive material.Type: GrantFiled: May 16, 1997Date of Patent: February 23, 1999Assignee: Fuji Photo Film Co., Ltd.Inventors: Isao Oyagi, Shingo Nishiyama, Nobuaki Inoue
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Patent number: 5547828Abstract: A direct positive type silver halide photographic material is described, which contains at least one compound represented by the following formula (I) and at least one cyanine dye having a pyrazolo[5,1-b]quinazolone nucleus and a cyanine heterocycle nucleus, wherein a carbon atom at 3-position of the pyrazolo[5,1-b]quinazolone nucleus is bonded through a four-methine chain to an atom at the 2-position or 4-position of the cyanine heterocycle nucleus, provided that the 4-position is possible only when the cyanine heterocycle nucleus is a quinoline or pyridine nucleus: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 each represents an alkyl group, an aryl group or a heterocyclic group, which may be substituted; V.sub.1, V.sub.2, V.sub.3, V.sub.4, V.sub.5, V.sub.6, V.sub.7 and V.sub.8 each represents a hydrogen atom or a monovalent substituent; L.sub.1, L.sub.2 and L.sub.3 each represents a substituted or unsubstituted methine group; M.sub.1 represents a charge-neutralizing counter ion; and m.sub.Type: GrantFiled: January 17, 1995Date of Patent: August 20, 1996Assignee: Fuji Photo Film Co., Ltd.Inventors: Takanori Hioki, Toyohisa Oya, Shingo Nishiyama
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Patent number: 5534402Abstract: A direct-positive silver halide photographic material is disclosed, which comprises a support having thereon at least one prefogged light-sensitive silver halide emulsion layer, wherein said silver halide emulsion is an emulsion which has been previously fogged with a gold compound and a tellurium compound.Type: GrantFiled: December 13, 1994Date of Patent: July 9, 1996Assignee: Fuji Photo Film Co., Ltd.Inventors: Koichi Kuno, Hiroyuki Mifune
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Patent number: 5240828Abstract: Room light handleable direct reversal silver bromide emulsions, with up to 70 mole percent chloride, have a broad Dmin window when from 1.times.10.sup.-6 to 1.times.10.sup.-4 mole per silver mole of a polybromo coordination complex of iridium is incorporated in the silver halide grains. The emulsions are stabilized against deterioration on keeping with mercapto compounds.Type: GrantFiled: September 10, 1990Date of Patent: August 31, 1993Assignee: Eastman Kodak CompanyInventors: Gaile A. Janusonis, Francis R. Hilton, Jr., Richard D. Lucitte, Woodrow G. McDugle, Roger Lok, David Erdtmann
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Patent number: 5221601Abstract: UV sensitive direct positive silver halide photographic material for duplicating processes which can be safely handled under roomlight conditions, said material comprising a support having thereon at least one silver halide emulsion layer comprising a prefogged direct positive silver halide emulsion, preferably one having a chloride content of at least 70 mole % and comprising internal electron traps, said emulsion layer or a hydrophilic colloid layer in water-permeable relationship to said emulsion layer containing at least one nitro-substitued indazole or benzimidazole derivative and at least one non-nitro-substituted indazole or benzimidazole derivative.Type: GrantFiled: September 16, 1991Date of Patent: June 22, 1993Assignee: Agfa-Gevaert, N.V.Inventors: Marc B. Graindourze, Marc H. Van Bockstaele
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Patent number: 5206132Abstract: A direct positive silver halide photographic light-sensitive material which is improved in gradation and suitable for rapid processing comprises a support having thereon a silver halide emulsion layer containing surface-fogged type direct positive silver halide grains, wherein said direct positive silver halide emulsion layer comprises two or more silver halide emulsions substantially different in sensitivity and/or gradation; the ratio of the total area of (111) face to and total surface area of grains in said emulsions is not less than 50%; and the average silver iodide content of grains in said emulsions is not more than 5 mol%.Type: GrantFiled: May 3, 1991Date of Patent: April 27, 1993Assignee: Konica CorporationInventor: Tsuyoshi Mitsuhashi
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Patent number: 5198333Abstract: A new class of electron-accepting compounds for photographic emulsions is disclosed represented by following general formula (I): ##STR1## wherein: each of Z and Q which may be the same or different represents the atoms necessary to complete an unsubstituted or substituted nitrogen-containing heterocyclic ring;each of T.sub.1 and T.sub.2 which may be the same or different represents alkyl, cycloalkyl, alkoxy, aryl, aryloxy, halogen, cyano, hydroxy, carboxyl, sulfo, carbamoyl, acyl, acylamino, sulfamoyl, sulfonamido or a benzocondensed ring, each of which can be further substituted or not;q=1, 2 or 3, and p and r=0, 1 or 2.In this formula the nitro containing heterocyclic nucleus is preferably nitropyridine or nitrothiazole.In a preferred embodiment of the invention electron-accepting compounds are incorporated in negative or direct positive roomlight emulsions. In the latter case the emulsion layer preferably contains in addition a nitroindazole or nitrobenzimidazole derivative.Type: GrantFiled: March 13, 1991Date of Patent: March 30, 1993Assignee: Agfa-Gevaert, N.V.Inventors: Jean-Marie O. Dewanckele, Paul R. Callant, Marc H. Van Bockstaele, Marc B. Graindourze
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Patent number: 5185241Abstract: Disclosed is a direct positive photographic material comprising a support having thereon at least one photographic emulsion layer containing previously non-fogged internal latent image-type silver halide grains, wherein the photographic emulsion layer contains at least one compound of formulae (I), (II) and (III) preferably along with at least one compound of formulae (IV), (V) and (VI), and that the internal latent image-type silver halide grains are silver bromide, silver chloride, silver iodobromide, silver chlorobromide or silver chloroiodobromide grains and contain at least one metal of manganese, copper, zinc, cadmium, rhenium, lead, bismuth, indium, thallium, zirconium, lanthanum, chromium, mercury and metals of Group VIII of the Periodic Table.M.sub.2 SO.sub.3 (I)MHSO.sub.3 (II)M.sub.2 S.sub.2 O.sub.5 (III)wherein M represents a hydrogen atom or a cation.R--SO.sub.2 S--M.sup.1 (IV)R--SO.sub.2 S--R.sup.1 (V)R--SO.sub.2 S--L.sub.m --S.O.sub.2 S--R.sup.2 (VI)wherein R, R.sup.1 and R.sup.Type: GrantFiled: January 11, 1991Date of Patent: February 9, 1993Assignee: Fuji Photo Film Co., Ltd.Inventor: Noriyuki Inoue
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Patent number: 5185240Abstract: Disclosed is an autopositive silver halide photographic material which comprises at least one silver halide emulsion layer, characterized in that said emulsion layer or at least one other hydrophilic colloid layers contains at least one compound selected from the group consisting of compounds represented by the following general formulas (1), (2) and (3): ##STR1## wherein R.sub.1 represents hydrogen atom or an alkyl group; and R.sub.2, R.sub.3 and R.sub.4 each represents hydrogen atom, a halogen atom, an alkyl group or an alkoxy group; ##STR2## wherein R.sub.5 represents hydrogen atom or an alkyl group; and R.sub.6 and R.sub.7 each represents hydrogen atom, an alkyl group, a halogen atom or an aryl group; ##STR3## wherein R.sub.8 represents a lower alkylene group; X represents a halogen atom, nitro group, hydroxy group, a cyano group, a lower alkyl group, a lower alkoxy group, ##STR4## or --SO.sub.3 M; R.sub.12 represents hydrogen atom, --OM, a lower alkyl group, a lower alkoxy group or ##STR5## R.sub.Type: GrantFiled: August 10, 1990Date of Patent: February 9, 1993Assignee: Fuji Photo Film Co., Ltd.Inventors: Junji Miyata, Satoshi Kanetake, Yasufumi Morimoto, Kenji Hanayama
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Patent number: 5147754Abstract: A silver halide photographic material which provides a negative image contains a compound represented by formula (I): ##STR1## wherein R represents an aliphatic group, an aromatic group, or a heterocyclic group; Z represents a development inhibitor group containing an anionic functional group as a partial structure; "Time" represents a divalent group; and n is 0 or 1.Type: GrantFiled: August 7, 1991Date of Patent: September 15, 1992Assignee: Fuji Photo Film Co., Ltd.Inventors: Hisashi Okamura, Hisashi Okada, Morio Yagihara, Kazunobu Katoh
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Patent number: 5112732Abstract: A direct positive silver halide photographic material is disclosed, comprising a support having thereon at least one internal latent image silver halide emulsion layer which has not been prefogged and another hydrophilic colloid layer wherein the grains in the internal latent image silver halide emulsion is formed in the presence of an iron complex compound. The direct positive silver halide photographic material is developed and then direct positive images may be obtained with this material, which feature a high D.sub.max and a low D.sub.min. The disclosed material has a broad range of applications, including as a COM film.Type: GrantFiled: March 28, 1990Date of Patent: May 12, 1992Assignee: Fuji Photo Film Co., Ltd.Inventors: Kazunori Hayashi, deceased, Masahiro Hayashi, heir, Masako Hayashi, heir
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Patent number: 5100761Abstract: A silver halide photographic material comprising one or more silver halide emulsion layers and hydrophilic colloid layers, wherein at least one of the layers contains an acylhydrazine compound as described below. The instant photographic materials have high contrast negative-gradation or positive-gradation characteristics, high maximum image density, excellent reversal characteristics and long-term storage stability.Type: GrantFiled: March 21, 1988Date of Patent: March 31, 1992Assignee: Fuji Photo Film Co., Ltd.Inventors: Morio Yagihara, Hisashi Okada, Kazunobu Katoh, Noriyuki Inoue, Shingo Nishiyama, Tetunori Matushita
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Direct positive silver halide photographic light-sensitive material and a processing method therefor
Patent number: 5049483Abstract: There is disclosed a direct positive silver halide light-sensitive material which can be processed in ultra-rapid processing and have a higher sensitivity, a lower Dmin, an excellent antistatic property and less flactuation of the properties in storing. The light-sensitive material contains an electron-accepting compound in a silver halide emulsion layer, and a fluorinated surfactant and/or at least one of the compounds represented by Formulas I-a to II-b in a photographic component layer: ##STR1## wherein R.sub.1 to R.sub.4 represent independently a hydrogen atom, a lower alkyl group, an alkoxy group, a carboxy group, an alkoxycarbonyl group, a sulfo group, a halogen atom, and a nitro group, provided that at least one of R.sub.1 and R.sub.2 is a carboxy group, an alkoxycarbonyl group or a sulfo group.Type: GrantFiled: June 4, 1990Date of Patent: September 17, 1991Assignee: Konica CorporationInventors: Naoko Yatsuyanagi, Tsuyoshi Mitsuhashi -
Patent number: 5043259Abstract: A pre-fogged direct positive silver halide emulsion comprising silver halide grains which have been formed in the presence of a compound represented by the following formula (I):R--SO.sub.2 --M (I)wherein R represents an aliphatic group, an aromatic group or a heterocyclic group, and M represents a hydrogen atom or a cation. The invention also relates to a method for making such a photographic material.Type: GrantFiled: May 24, 1990Date of Patent: August 27, 1991Assignee: Fuji Photo Film Co., Ltd.Inventor: Naoki Arai
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Patent number: 4971899Abstract: Direct positive photographic films are disclosed having novel density enhancers of the formula ##STR1## wherein A is oxygen or sulfur, and B is selected from the group consisting of hydrogen, alkyl haloalkyl, hydroxyalkyl, alkylamino and alkoxy. Photographic materials coated with emulsions having these density enhancers display good optical density while maintaining high speed capability.Type: GrantFiled: May 5, 1989Date of Patent: November 20, 1990Assignee: Sun Chemical CorporationInventors: Steven R. Gallo, John Abbruzzese, Adelberto Aguero
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Patent number: 4933273Abstract: A photographic element and emulsion are described which comprise a negative working silver halide emulsion layer, a hydrazine compound nucleating agent and an electron accepting antifogging dye. Enhanced sensitometric properties are obtained. A process for developing such element or emulsion is also described.Type: GrantFiled: December 2, 1988Date of Patent: June 12, 1990Assignee: Eastman Kodak CompanyInventors: Paul B. Gilman, Jr., Thaddeus D. Koszelak, Anthony Adin, Roland G. Willis
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Patent number: 4849326Abstract: UV-sensitive direct positive silver halide photographic elements for duplicating processes which can be safely handled under white light, said elements comprising a support base, a hydrophilic colloidal silver halide emulsion layer comprising fogged silver halide grains, and one or more hydrophilic colloidal layers, wherein said silver halide emulsion is reactively associated with a water-removable UV-absorbing compound having at least 80% of the absorption in the range from 350 to 400 .mu.m.Type: GrantFiled: July 8, 1988Date of Patent: July 18, 1989Assignee: Minnesota Mining and Manufacturing CompanyInventors: Mauro Besio, Alberto Vacca, Angelo Vallarino
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Patent number: 4840889Abstract: Silver halide photographic paper for direct positives, comprising a support and a silver halide emulsion layer for direct positives, provided on the support and containing silver halide grains having been fogged in the presence of a reduction fogging agent and a water-soluble gold compound, wherein a photographic layer on the side on which said silver halide emulsion layer for direct positives is provided contains an emulsion dispersion or latex dispersion of an oil-soluble brightening agent, and simultaneously contains at least one of organic desensitizers represented by formula (I), (II), (III), (IV) or (V) as shown in the specification.Type: GrantFiled: September 8, 1987Date of Patent: June 20, 1989Assignee: Konishiroku Photo Industry Co., Ltd.Inventors: Yutaka Uesawa, Isamu Morimoto
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Patent number: 4839271Abstract: A fogged direct positive photographic silver halide emulsion containing a sensitizing amount of at least one cyanine dye defined above, e.g., cyanine dye containing a 1-phenylindole nucleus substituted in the 2-position with the 3-pyridyl group. The said cyanine dye is also covered. The dye useful in sensitizing the silver halide emulsion useful for fogged direct-positive films.Type: GrantFiled: June 26, 1987Date of Patent: June 13, 1989Assignee: E. I. Du Pont de Nemours and CompanyInventor: Thomas D. Weaver
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Patent number: 4820625Abstract: A direct positive silver halide photographic material comprising a support having thereon at least one silver halide emulsion layer comprising a prefogged direct-positive silver halide emulsion, preferably one having a chloride content of at least 70 mol%, said emulsion layer or a hydrophilic colloid layer adjacent to said emulsion layer containing at least one compound represented by the following general formula (I) and, optionally, a specified organic desensitizer, ##STR1## wherein Z.sub.Type: GrantFiled: September 21, 1987Date of Patent: April 11, 1989Assignee: Fuji Photo Film Co., Ltd.Inventors: Naomi Saeki, Nobuaki Inoue, Toshinao Ukai, Yuji Mihara
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Patent number: 4814263Abstract: A direct-positive silver halide emulsion comprising fine grain reduction and gold surface fogged silver halide grains containing an electron-trapping effective amount of at least one Group VIII metal dopant, at least 75% by weight of all silver halide grains in said emulsion being silver halide grains wherein at least 80 mole percent of the halide within said grains is chloride.Type: GrantFiled: July 21, 1987Date of Patent: March 21, 1989Assignee: Minnesota Mining and Manufacturing CompanyInventor: Philip Hine
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Patent number: 4756995Abstract: A direct reversal silver halide photographic light-sensitive material is disclosed. The material is comprised of a support having thereon a silver halide emulsion layer having silver halide grains, the surface of which is preliminarily fogged, rhodium as a desensitizer, and a dye having an absorption maximum within the range of from 470 to 520 nm. The dye is represented by the general formula (I): ##STR1## The substituents within general formula (I) are defined in the specification. The material has improved safety with respect to visible safe light and does not suffer color stain after photographic development processing. Further, the dye is stable in a solution state during processing.Type: GrantFiled: November 21, 1985Date of Patent: July 12, 1988Assignee: Fuji Photo Film Co., Ltd.Inventors: Tetsuro Kojima, Nobuaki Inoue, Tadashi Ikeda
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Patent number: 4701398Abstract: A new group of cyanine and merocyanine spectral sensitizing dyes based on derivatives of 3-indolizine carboxaldehyde is particularly useful in sensitizing a direct positive silver halide emulsion to orange and red.Type: GrantFiled: March 14, 1986Date of Patent: October 20, 1987Assignee: E. I. Du Pont de Nemours and CompanyInventor: James W. Wheeler
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Patent number: 4539291Abstract: A direct positive silver halide material is disclosed. The material is comprised of a support base having a silver halide emulsion layer thereon which contains at least one phenazine series compound represented by the general formula (I), (II) or (III) and at least one compound represented by the general formula (IV), (V) or (VI). The structural formulae are shown within the specification wherein their substituents are defined. By including one compound of each of these groups within the material the resulting material provides images with a reduced minimum density without reducing the contrast of the images formed.Type: GrantFiled: December 19, 1983Date of Patent: September 3, 1985Assignee: Fuji Photo Film Co., Ltd.Inventors: Nobuaki Inoue, Hiroyuki Mifune, Koki Nakamura
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Patent number: 4495274Abstract: Direct positive silver halide photographic materials comprising a support, a silver halide emulsion layer comprising fogged silver halide particles prepared in the presence of a water soluble iridium salt or a water soluble rhodium salt, and a hydrophilic colloidal layer comprising (a) a compound selected from Formula I and II and (b) at least one compound selected from the group consisting of Formula III and a gold compound, said Formula I being ##STR1## wherein R.sub.1 is hydrogen, alkyl, --SO.sub.3 M, or --COOM, wherein M is selected from hydrogen, alkali metals, and ammonium, and R.sub.2 is selected from hydrogen and lower alkyls, said Formula II being ##STR2## wherein R.sub.3 is selected from hydrogen, alkyl, --SO.sub.3 M, and --COOM, and R.sub.4 is selected from hydrogen, alkyl, and --CH.sub.2 --S--(CH.sub.2).sub.n --Y', wherein n is an integer of from 1 to 3, and Y' is selected from hydrogen and --SO.sub.3 M, and said Formula III beingH.sub.2 N--Y--NH--Y].sub.m NH.sub.Type: GrantFiled: April 21, 1983Date of Patent: January 22, 1985Assignee: Konishiroku Photo Industry Co., Ltd.Inventor: Kazuhiro Yoshida
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Patent number: 4472497Abstract: Many photographic materials must be handled under special lighting conditions in order to prevent exposure of the material. The use of large concentrations of bleachable light absorbing layers over the photosensitive emulsion tends to leave an undesirable residual stain. The inclusion of a specific class of low intensity reciprocity failure inducers to silver halide emulsions enables the emulsions and their photographic articles to be safely handled under white light conditions.Type: GrantFiled: February 18, 1983Date of Patent: September 18, 1984Assignee: Minnesota Mining and Manufacturing CompanyInventors: Jonathan P. Kitchin, Robert F. Coles
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Patent number: 4404277Abstract: Novel cyanine dye salts having an alkoxyaryl function joined by a vinylene linkage to a heterocyclic nucleus are useful as desensitizers in fogged, direct positive type of silver halide emulsions.Type: GrantFiled: August 21, 1981Date of Patent: September 13, 1983Assignee: Minnesota Mining and Manufacturing CompanyInventor: Ivan H. Skoog
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Patent number: 4395483Abstract: A high contrast, chemically fogged direct positive type silver halide photosensitive material is described containing at least one ammine complex salt selected from those including cobalt, nickel, ruthenium or chromium, by which the contrast in the lower optical density region is improved while retaining superior Dmax and sensitivity.Type: GrantFiled: February 26, 1982Date of Patent: July 26, 1983Assignee: Fuji Photo Film Co., Ltd.Inventors: Terumi Matsuda, Shoji Ishiguro, Shigenori Moriuchi, Yoshiaki Suzuki
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Patent number: 4376817Abstract: Direct-positive photographic material having at least one layer which contains a silver halide emulsion surface-fogged by chemical means or by exposure and a tri-nuclear cyanine dye, which has the formula ##EQU1## in which A.sub.1 is .dbd.CH-- or .dbd.CH--CH.dbd.CH--, Z.sub.1 is a monocyclic or polycyclic heterocyclic radical which is linked by a double bond to the adjacent methine group, Z.sup..sym. is a positively charged radical which is mesomeric to Z.sub.1 and is linked by a single bond to the adjacent methine group, Z.sub.2 --is a nitrogen-heterocyclic radical which has its single positive charge on the nitrogen atom and Z.sub.3 .dbd. is a radical which has no charge on the nitrogen atom and is mesomeric to Z.sub.2, at least one of the radicals Z.sub.Type: GrantFiled: July 27, 1981Date of Patent: March 15, 1983Assignee: Ciba-Geigy AGInventors: Rolf Steiger, Jean F. Reber
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Patent number: 4355098Abstract: Direct positive photographic elements with improved spectral sensitivity in the green and red portion of the visible spectrum are obtained from emulsions containing a supersensitizing amount of a spectral sensitizing dye (a) having a solution absorption maximum less than 495 nm and the lowest vacant energy band less than -3.7 eV, and a sensitizing amount of a spectral sensitizing dye (b) having a lowest vacant energy band between -3.7 eV and 0.3 eV below the lowest vacant energy band of said spectral sensitizing dye (a) and with the highest occupied energy band between -5.9 eV and 0.3 eV above the highest occupied energy level of dye (a).Type: GrantFiled: February 11, 1981Date of Patent: October 19, 1982Assignee: E. I. Du Pont de Nemours and CompanyInventor: James W. Wheeler
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Patent number: 4311786Abstract: Direct-positive photographic material which has at least one layer which contains a silver halide emulsion surface-fogged by chemical means or by exposure and, as a sensitizer, a trinuclear tetramethinecyanine dye in which all or some of the methine hydrogen atoms have been replaced by fluorine, chlorine, bromine or iodine atoms. The novel trinuclear tetramethinecyanine dyes impart an excellent blue-sensitivity to the photographic materials. Furthermore, high maximum densities and very low minimum densities are achieved.Type: GrantFiled: July 11, 1980Date of Patent: January 19, 1982Assignee: Ciba-Geigy AGInventors: Rolf Steiger, Jean F. Reber
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Patent number: 4287296Abstract: Direct positive silver halide emulsions are provided which contain fogged silver halide grains the said grains being heterodisperse and containing silver iodide in an amount of more than 10 mole % and at most 20 mole % relative to the total amount of silver halide. The emulsions have increased sensitivity and reduced gradation which is suitable for continuous tone reproduction.Type: GrantFiled: November 20, 1973Date of Patent: September 1, 1981Assignee: Agfa-Gevaert, N.V.Inventors: Willy J. Vanassche, Herman A. Pattyn, Erik Moisar, Sieghart Klotzer
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Patent number: 4273862Abstract: Direct-positive silver halide photographic sensitive materials of high sensitivity and capable of forming a high-contrast image are obtained by incorporating anion-type cyanine dyes having a polarographic oxidation halfwave potential not less positive than +0.4 V in externally fogged direct-positive silver halide emulsions containing not less than 70 mole-% of bromide. Additional incorporation of a development accelerator such as 2-mercaptoimidazoline improves developability.Type: GrantFiled: September 24, 1979Date of Patent: June 16, 1981Assignee: Mitsubishi Paper Mills, Ltd.Inventors: Akio Yoshida, Seigo Ebato
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Patent number: 4259439Abstract: A high-contrast direct positive prefogged silver halide emulsion free from coror stain, which contains at least one new dimethinecyanine dye wherein the 3-position of a pyrazolo[1,5-a]pyridine nucleus is bonded through a dimethine chain to the 1-, 2-, 3- or 4-position of a cyanine hetero ring nucleus, provided that where the bonding is in the 4-position said cyanine nucleus is a quinoline nucleus or a pyridine nucleus and where the bonding is in the 1- or 3-position said cyanine nucleus is an isoquinoline nucleus, said dimethyinecyanine dye being present in an amount sufficient to sensitize said emulsion.Type: GrantFiled: October 17, 1978Date of Patent: March 31, 1981Assignee: Mitsubishi Paper Mills, Ltd.Inventors: Akira Tanaka, Akio Yoshida, Kozo Haino