EP0691569A1 - Photographic emulsion with improved sensitivity - Google Patents

Photographic emulsion with improved sensitivity Download PDF

Info

Publication number
EP0691569A1
EP0691569A1 EP95420173A EP95420173A EP0691569A1 EP 0691569 A1 EP0691569 A1 EP 0691569A1 EP 95420173 A EP95420173 A EP 95420173A EP 95420173 A EP95420173 A EP 95420173A EP 0691569 A1 EP0691569 A1 EP 0691569A1
Authority
EP
European Patent Office
Prior art keywords
photographic emulsion
emulsion
gold
silver
sensitized
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95420173A
Other languages
German (de)
English (en)
French (fr)
Inventor
Jacques Kodak-Pathe Roussilhe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kodak Pathe SA
Eastman Kodak Co
Original Assignee
Kodak Pathe SA
Eastman Kodak Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from FR9408439A external-priority patent/FR2722008A1/fr
Application filed by Kodak Pathe SA, Eastman Kodak Co filed Critical Kodak Pathe SA
Publication of EP0691569A1 publication Critical patent/EP0691569A1/en
Withdrawn legal-status Critical Current

Links

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
    • G03C1/09—Noble metals or mercury; Salts or compounds thereof; Sulfur, selenium or tellurium, or compounds thereof, e.g. for chemical sensitising

Definitions

  • the present invention concerns a silver halide photographic emulsion with improved sensitivity.
  • silver halide emulsions that is to say emulsions whose coefficient of variation, defined as the relationship 100 x (sigma/v), where sigma is the volume standard deviation and v the mean volume of the population of the grains, is greater than 35% and preferably greater than 25%.
  • Silver halide emulsions comprising at least two halides are also known, one of which is present in a higher concentration in at least one region or phase of the grain.
  • silver bromoiodide emulsions of advantageous sensitivity can be obtained, when the iodide is localised in precise phases of the grains, as is the case for example with so-called "core/shell" emulsions. It is also desirable to use monodisperse emulsions when it is wished to modify the form of the sensitometric curve and especially the contrast, including by mixing two or more monodisperse emulsions.
  • silver bromoiodide emulsions with localised iodide are more difficult to prepare than emulsions where the iodide is distributed throughout the grain.
  • the object of the present invention is a monodisperse silver bromoiodide emulsion, chemically sensitized to an optimum extent, but without its stability in storage being affected.
  • the photographic emulsion according to the invention is a monodisperse silver bromoiodide emulsion where the iodide is uniformly distributed in the grains (uniform intra-grain distribution), chemically sensitized with sulphur and gold, to the same level as a polydisperse silver bromoiodide emulsion, with the same speed/granularity compromise.
  • the addition of the gold and sulphur sensitisers is effected at a temperature between 30 and 60°C and advantageously between 40 and 50°C.
  • Gold sensitisers are well known. These are notably the gold salts with a degree of oxidation of +1 or +3, described in US patents 2,399,083, 2,597,915 or 2,597,856. Suitable compounds are for example potassium chloroaurite, potassium chloroaurate, ammonium aurithiocyanate, potassium iodoaurate, potassium aurithiocyanate, auric triochloride, N-methyl-2-aurobenzosulphobenzothiazolium chloride, and bis (1,4,5-trimethyl-1,2,4-triazolium-3-thiolate)-Au(I)-tetrafluoroborate.
  • Preferred gold sensitizers are the gold (I) compounds disclosed in USP 5,049,485. These compounds include those represented by the formula : AuL2+X ⁇ or AuL(L1)+X ⁇ wherein L is a mesoionic compound X is an anion and L1 is Lewis acid donor.
  • Sulphur sensitisers are also known. These are principally alkali metal thiosulphates, thiourea or thiourea derivatives, thioethers, etc. Useful compounds as well as the afore mentioned gold sensitizers are described in Research Disclosure, September 1994, publication 36544, Section IV, "Chemical Sensitisation”. These gold and sulphur sensitisers are used in quantities which are well known and reported in the literature. For example, the gold compound is used in a proportion of 10 ⁇ 6 moles to 10 ⁇ 1 moles per mole of silver and the sulphur compound in a proportion of 10 ⁇ 5 moles to 10 ⁇ 1 moles per mole of silver.
  • the thiocyanate used in step (b) of the process defined above is preferably a thiocyanate of an alkali metal, sodium or potassium.
  • the optimum quantity of thiocyanate depends on the composition of the emulsion and the desired characteristics, but is in general between 0.1 and 1.5 g/mole of silver and preferably between 0.2 and 1.0 g/mole of silver.
  • the temperature stage is observed for a conventional period, usually lying between 5 and 60 minutes and advantageously between 10 and 30 minutes.
  • a modifying compound is added which is able to reduce fogging without reducing sensitivity.
  • the invention therefore comprises the embodiment which consists of using such modifying agents.
  • These agents are azaindenes, azapyrimidines, benzothiazolium salts and compounds with one or more heterocycles. Examples of these compounds are cited in US patents 2,131,038, 3,411,914, 3,554,754, 3,565,631 and 3,901,714, in Canadian patent 778,723 and in Photographic Emulsion Chemistry by Duffin, Focal Press (1966) New York, pages 138-143, or in Research Disclosure, September 1994, publication No 36544, section VII.
  • phenylmercaptotetrazole antifogging agents Any of the mercaptoheterocyclic nitrogen compounds, as described herein, will act as antifoggants in the practice of this invention. However, particularly good results are obtained with the mercaptotetrazoles, especially the 5-mercaptotetrazoles.
  • 5-mercaptotetrazoles which can be employed include those having the structure : where R is a hydrocarbon (aliphatic or aromatic) radical containing up to 20 carbon atoms. The hydrocarbon radicals comprising R can be substituted or unsubstituted.
  • Suitable substituents include, for example, alkoxy, phenoxy, halogen, cyano, nitro, amino, amido, carbamoyl, sulfamoyl, sulfonamido, sulfo, sulfonyl, carboxy, carboxylate, ureido and carbonyl phenyl groups.
  • an -SH group as shown in formula A-I, an -SM group can be substituted, where M represents a monovalent metal cation.
  • Various other conventional substances may be added to the emulsion, during or after precipitation.
  • solvents for silver halides maturation agents, such as in particular thioethers as described in US patents 3,062,646 or 3,271,157, dyes for spectral sensitisation, dopants, or other modifying agents.
  • dyes for spectral sensitisation dyes for spectral sensitisation, dopants, or other modifying agents.
  • These compounds may be adsorbed on the surface of the grains, or at certain predetermined places on this surface, or buried in the grains.
  • the additives may be introduced initially into the precipitation reactor, or added separately with one of the halides then introduced into the reactor, in accordance with normal techniques.
  • dopants such as compounds of noble metals in group VIII, may be present during the precipitation.
  • the silver salts and halides may be introduced into the reactor by means of feed pipes arriving just below the surface of the contents of the reactor, whilst controlling the flow rate, pH and pAg. Suitable techniques are described in US patents 3,821,002 and 3,031,304, and by Claes et al in Photographisches Korrespondenz, Vol 102, No 10, page 162, 1967. Agitation arrangements can be provided to accelerate the homogenisation of the reagents in the reactor, as described in Research Disclosure, Vol 166, paragraph 16662, February 1978, or in US patents 2,996,287, 3,342,605, 3,415,650, 3,785,777, 4,147,551 and 4,171,224.
  • a dispersion medium is first introduced into the reactor, this normally consisting of a mixture of water and a vehicle which is a binder and/or a peptiser.
  • This vehicle is usually a hydrophilic colloid, notably a proteinic one, such as gelatin, for example bone gelatin (treated with an alkali), pigskin gelatin (treated with an acid), modified gelatin, for example acetylated gelatin, phthalylated gelatin, etc, optionally associated with hydrophobic substances.
  • the vehicle may also comprise synthetic substances, for example acrylamide polymers, cellulose derivatives, polyvinyl alcohol, etc. These substances do not necessarily have to be present at the time of precipitation. They may be added at the time of coating.
  • the emulsion is preferably washed in order to eliminate the soluble salts therefrom. This may be achieved by decantation, filtration, solidification, coagulation, centrifugation or flocculation, as described for example in US patents 2,316,845, 3,396,027, 2,618,556, 2,614,928, 2,565,418, 3,241,969, 2,489,341, 2,996,287, 3,498,454.
  • the emulsions can be dried and kept before use, as described in Research Disclosure, Vol 101, paragraph 10152, September 1972.
  • the emulsion may contain yet other substances such as light-absorbent agents, surfactants, tanning agents, etc. These agents may also be incorporated in auxiliary layers. Information concerning these agents are given in Research Disclosure, September 1994, sections VIII and IX.
  • the emulsion according to the invention can be spectrally sensitized by the addition of one or more sentising dyes.
  • the sentising dye can be added at different stages in the preparation of the emulsion.
  • the most usual operating methods consisting of adding it just before the sensitisation or chemical maturation, during this maturation or afterwards.
  • the usual sensitising dyes are well known; these are for example cyanines or merocyanines described with their bibliographic references in Research Disclosure, December 1989, publication No 308119, Section IV, "Spectral Sensitisation and Desensitisation".
  • An emulsion of silver bromoiodide was prepared, containing 3% molar silver iodide, by the double jet technique.
  • an initial growth step was effected by introducing, by the accelerated double jet method, the following reagents: AgNO3 (2 M/l) NaBr (1.94 M/l) KI (0.06 M/l) duration 27.2 minutes pAg 9.3 temperature 60°C
  • a second growth step was effected with the following parameters and the following reagents, introduced by double jet method at constant flow rates: AgNO3 (2M/l) NaBr 1.94 M/l) KI (0.06 M/l) 36.7 minutes pAg 9.3 temperature 60°C
  • a 20 minute stage is effected at 70°C.
  • the emulsion was then hold at 70°C for 20 minutes.
  • the emulsion samples were coated at 8.07 x 100 mg of Ag, 32.3 x 100 mg gelatin and 10.5 x 100 mg of coupler per m.
  • the coatings were exposed 1/100 sec at a tungsten source of 5500°K through a Wratten filter No 9, plus a color conversion filter DL5A.
  • the ESD is 1.085 ⁇ m for sample A, and 0.66 ⁇ m for sample B.
  • the COV (by volume) is 6.1% for A and 9.6% for B.
  • the two samples were developed for 3 minutes 15 seconds in an AUTOPAN machine using the Kodak C41 process for colour negative development.
  • the coupler had the formula:
  • Example 1 The operating method of Example 1 was repeated, except that the sensitisation was effected as follows (quantities in mg/mole of silver) and the holding stage is 20 minutes at 60°C.
  • the anti-fogging modifier had the formula:
  • the gold compound is bis(1,4,5-trimethyl-1,2,4-triazolium-3-thiolate) Au(I) tetrafluororborate.
  • the emulsion was coated, exposed and developed as in Example 1.
  • a polydisperse silver bromoiodide emulsion with 12% molar iodide was prepared, sensitized with sulphur and gold with thiocyanate digestion and spectrally sensitized by means of the mixture of dyes I and III.
  • This emulsion had an equivalent diameter, of 0.84 ⁇ m and was coated at 8.07 x 100 mg of silver, 32.3 x 100 mg of gelatin and 10.5 x 100 mg of coupler per m.
  • the sensitising dyes had the formulas:
  • Example 1 The product is exposed and developed as in Example 1.
  • Table 1 The results obtained, appearing in Table 1, show that the monodisperse emulsions according to the invention give sensitometric results comparable to those of the reference emulsion of Example 3.
  • the coupler has the formula:

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
  • Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
EP95420173A 1994-07-04 1995-06-28 Photographic emulsion with improved sensitivity Withdrawn EP0691569A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
FR9408439A FR2722008A1 (fr) 1994-07-04 1994-07-04 Emulsion photografique a sensibilite amelioree
FR9413053A FR2722009A1 (fr) 1994-07-04 1994-10-26 Emulsion photografique a sensibilite ameloiree
FR9413053 1994-10-26
FR9408439 1994-10-26

Publications (1)

Publication Number Publication Date
EP0691569A1 true EP0691569A1 (en) 1996-01-10

Family

ID=26231277

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95420173A Withdrawn EP0691569A1 (en) 1994-07-04 1995-06-28 Photographic emulsion with improved sensitivity

Country Status (3)

Country Link
EP (1) EP0691569A1 (enrdf_load_stackoverflow)
JP (1) JPH0843977A (enrdf_load_stackoverflow)
FR (1) FR2722009A1 (enrdf_load_stackoverflow)

Citations (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2131038A (en) 1932-05-26 1938-09-27 Eastman Kodak Co Photographic emulsion containing alkyl quaternary salts of thiazoles and the like asantifoggants
US2316845A (en) 1942-07-15 1943-04-20 Defender Photo Supply Co Inc Method of chilling photographic emulsions
US2399083A (en) 1942-02-13 1946-04-23 Ilford Ltd Photographic materials
US2489341A (en) 1944-07-04 1949-11-29 Ilford Ltd Production of photographic silver halide emulsions
US2565418A (en) 1947-08-13 1951-08-21 Eastman Kodak Co Method of preparing photographic silver halide emulsions
US2597915A (en) 1949-09-24 1952-05-27 Eastman Kodak Co Stabilization of photographic emulsions sensitized with gold compounds
US2597856A (en) 1949-09-24 1952-05-27 Eastman Kodak Co Stabilization of photographic emulsions sensitized with gold compounds
US2614928A (en) 1947-08-13 1952-10-21 Eastman Kodak Co Method of preparing photographic emulsions
US2618556A (en) 1947-11-19 1952-11-18 Eastman Kodak Co Process for preparing photographic emulsions
US2996287A (en) 1957-07-05 1961-08-15 Eastman Kodak Co Apparatus for incorporating fluids into liquids
US3031304A (en) 1958-08-20 1962-04-24 Albert J Oliver Fine grain nuclear emulsion
US3062646A (en) 1959-03-06 1962-11-06 Eastman Kodak Co Sensitization of silver halide emulsions with macrocyclic compounds
US3241969A (en) 1961-01-27 1966-03-22 Hart Rene Maurice Photographic silver halide emulsions
US3271157A (en) 1962-09-11 1966-09-06 Eastman Kodak Co Light-developable direct-print silver halide emulsions
US3342605A (en) 1963-10-07 1967-09-19 Eastman Kodak Co Incorporation of certain addenda into aqueous gelatin solutions
CA778723A (en) 1968-02-20 Polaroid Corporation Photographic products and processes
US3396027A (en) 1964-05-13 1968-08-06 Eastman Kodak Co Method of noodling gelatin dispersions
US3411914A (en) 1963-12-05 1968-11-19 Eastman Kodak Co Method for stabilizing x-ray emulsions to red safelights
US3415650A (en) 1964-11-25 1968-12-10 Eastman Kodak Co Method of making fine, uniform silver halide grains
US3498454A (en) 1968-02-20 1970-03-03 Polaroid Corp Counter-current centrifugal device and use
US3554754A (en) 1966-12-24 1971-01-12 Kalle Ag Light-sensitive reproduction material
US3565631A (en) 1967-07-07 1971-02-23 Konishiroku Photo Ind 6 - amidinothio - 5,7 - dihydroxy - s - triazolo(2,3-a) pyrimidino compounds as stabilizers for silver halide emulsion
US3785777A (en) 1971-11-01 1974-01-15 Eastman Kodak Co Apparatus for the uniform preparation of silver halide grains
US3821002A (en) 1972-03-06 1974-06-28 Eastman Kodak Co Process control apparatus and method for silver halide emulsion making
US3901714A (en) 1974-07-29 1975-08-26 Eastman Kodak Co Silver halide emulsions and elements including sensitizers of adamantane structure
US4147551A (en) 1972-08-14 1979-04-03 E. I. Du Pont De Nemours And Company Process for photographic emulsion precipitation in a recycle stream
US4171224A (en) 1976-09-14 1979-10-16 Agfa-Gevaert N.V. Method and apparatus suitable for the preparation of AgX-emulsions
US4914017A (en) * 1987-06-16 1990-04-03 Fuji Photo Film Co., Ltd. Gold sensitized silver halide emulsion and photographic silver halide light-sensitive material using same
US5049485A (en) 1990-11-16 1991-09-17 Eastman Kodak Company Photographic silver halide material comprising gold compound
EP0521612A1 (en) 1991-05-30 1993-01-07 Konica Corporation Ultrafine gold and/or silver chalcogenide and production thereof
EP0541104A1 (en) 1991-11-06 1993-05-12 Konica Corporation Silver halide photographic emulsion and light-sensitive silver halide photographic material making use of the same
US5219721A (en) 1992-04-16 1993-06-15 Eastman Kodak Company Silver halide photographic emulsions sensitized in the presence of organic dichalcogenides
US5221604A (en) 1990-05-22 1993-06-22 Fuji Photo Film Co., Ltd. Silver halide photographic material
JPH05249584A (ja) * 1992-03-03 1993-09-28 Fuji Photo Film Co Ltd ハロゲン化銀乳剤ならびにそれを含むハロゲン化銀写真感光材料

Patent Citations (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA778723A (en) 1968-02-20 Polaroid Corporation Photographic products and processes
US2131038A (en) 1932-05-26 1938-09-27 Eastman Kodak Co Photographic emulsion containing alkyl quaternary salts of thiazoles and the like asantifoggants
US2399083A (en) 1942-02-13 1946-04-23 Ilford Ltd Photographic materials
US2316845A (en) 1942-07-15 1943-04-20 Defender Photo Supply Co Inc Method of chilling photographic emulsions
US2489341A (en) 1944-07-04 1949-11-29 Ilford Ltd Production of photographic silver halide emulsions
US2614928A (en) 1947-08-13 1952-10-21 Eastman Kodak Co Method of preparing photographic emulsions
US2565418A (en) 1947-08-13 1951-08-21 Eastman Kodak Co Method of preparing photographic silver halide emulsions
US2618556A (en) 1947-11-19 1952-11-18 Eastman Kodak Co Process for preparing photographic emulsions
US2597856A (en) 1949-09-24 1952-05-27 Eastman Kodak Co Stabilization of photographic emulsions sensitized with gold compounds
US2597915A (en) 1949-09-24 1952-05-27 Eastman Kodak Co Stabilization of photographic emulsions sensitized with gold compounds
US2996287A (en) 1957-07-05 1961-08-15 Eastman Kodak Co Apparatus for incorporating fluids into liquids
US3031304A (en) 1958-08-20 1962-04-24 Albert J Oliver Fine grain nuclear emulsion
US3062646A (en) 1959-03-06 1962-11-06 Eastman Kodak Co Sensitization of silver halide emulsions with macrocyclic compounds
US3241969A (en) 1961-01-27 1966-03-22 Hart Rene Maurice Photographic silver halide emulsions
US3271157A (en) 1962-09-11 1966-09-06 Eastman Kodak Co Light-developable direct-print silver halide emulsions
US3342605A (en) 1963-10-07 1967-09-19 Eastman Kodak Co Incorporation of certain addenda into aqueous gelatin solutions
US3411914A (en) 1963-12-05 1968-11-19 Eastman Kodak Co Method for stabilizing x-ray emulsions to red safelights
US3396027A (en) 1964-05-13 1968-08-06 Eastman Kodak Co Method of noodling gelatin dispersions
US3415650A (en) 1964-11-25 1968-12-10 Eastman Kodak Co Method of making fine, uniform silver halide grains
US3554754A (en) 1966-12-24 1971-01-12 Kalle Ag Light-sensitive reproduction material
US3565631A (en) 1967-07-07 1971-02-23 Konishiroku Photo Ind 6 - amidinothio - 5,7 - dihydroxy - s - triazolo(2,3-a) pyrimidino compounds as stabilizers for silver halide emulsion
US3498454A (en) 1968-02-20 1970-03-03 Polaroid Corp Counter-current centrifugal device and use
US3785777A (en) 1971-11-01 1974-01-15 Eastman Kodak Co Apparatus for the uniform preparation of silver halide grains
US3821002A (en) 1972-03-06 1974-06-28 Eastman Kodak Co Process control apparatus and method for silver halide emulsion making
US4147551A (en) 1972-08-14 1979-04-03 E. I. Du Pont De Nemours And Company Process for photographic emulsion precipitation in a recycle stream
US3901714A (en) 1974-07-29 1975-08-26 Eastman Kodak Co Silver halide emulsions and elements including sensitizers of adamantane structure
US4171224A (en) 1976-09-14 1979-10-16 Agfa-Gevaert N.V. Method and apparatus suitable for the preparation of AgX-emulsions
US4914017A (en) * 1987-06-16 1990-04-03 Fuji Photo Film Co., Ltd. Gold sensitized silver halide emulsion and photographic silver halide light-sensitive material using same
US5221604A (en) 1990-05-22 1993-06-22 Fuji Photo Film Co., Ltd. Silver halide photographic material
US5049485A (en) 1990-11-16 1991-09-17 Eastman Kodak Company Photographic silver halide material comprising gold compound
EP0521612A1 (en) 1991-05-30 1993-01-07 Konica Corporation Ultrafine gold and/or silver chalcogenide and production thereof
EP0541104A1 (en) 1991-11-06 1993-05-12 Konica Corporation Silver halide photographic emulsion and light-sensitive silver halide photographic material making use of the same
JPH05249584A (ja) * 1992-03-03 1993-09-28 Fuji Photo Film Co Ltd ハロゲン化銀乳剤ならびにそれを含むハロゲン化銀写真感光材料
US5219721A (en) 1992-04-16 1993-06-15 Eastman Kodak Company Silver halide photographic emulsions sensitized in the presence of organic dichalcogenides

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
"Chemical Sensitisation", RESEARCH DISCLOSURE, vol. 365, no. 044, September 1994 (1994-09-01)
A. HOLLAND AND A. FEINERMAN, J APPLIED PHOTO. ENGIN, vol. 8, 1982, pages 165
CLAES ET AL., PHOTOGRAPHISCHES KORRESPONDENZ, vol. 102, no. 10, 1967, pages 162
DUFFIN: "Photographic Emulsion Chemistry", 1966, FOCAL PRESS, NEW YORK, pages: 138 - 143
RESEARCH DISCLOSURE, vol. 101, no. 052, September 1972 (1972-09-01)
RESEARCH DISCLOSURE, vol. 166, no. 062, February 1978 (1978-02-01)
RESEARCH DISCLOSURE, vol. 308, no. 119, December 1989 (1989-12-01)

Also Published As

Publication number Publication date
FR2722009B1 (enrdf_load_stackoverflow) 1997-02-14
FR2722009A1 (fr) 1996-01-05
JPH0843977A (ja) 1996-02-16

Similar Documents

Publication Publication Date Title
US4183756A (en) Pre-precipitation spectral sensitizing dye addition process
US4804621A (en) Process for the preparation of tabular silver chloride emulsions using a grain growth modifier
US3892574A (en) Controlled reduction of silver halide grains formed during precipitation
US4349622A (en) Photographic silver halide emulsion comprising epitaxial composite silver halide crystals, silver iodobromide emulsion and process for preparing the same
US4746593A (en) Silver halide radiation-sensitive photographic materials
EP0517893B1 (en) Selenium and iridium doped emulsions
EP0285308B1 (en) High contrast photographic materials
US4286055A (en) Process for the preparation of monodisperse photographic silver halide emulsions of improved sensitivity
EP0102320B1 (en) Process for the preparation of a silver halide emulsion
EP0691569A1 (en) Photographic emulsion with improved sensitivity
US4241173A (en) Process for the preparation of silver halide emulsions
GB2053499A (en) Photographic silver halide emulsion and process for preparing same
EP0428334B1 (en) Process for the spectral sensitisation of photographic silver halide emulsions and products thereof
JP2849864B2 (ja) ハロゲン化銀写真感光材料及びその処理方法
RU2085987C1 (ru) Галогенсеребряный фотографический материал
JP2925353B2 (ja) ハロゲン化銀写真材料
JP2857716B2 (ja) 直接ポジハロゲン化銀写真感光材料
EP0445444A1 (en) Photographic emulsions
JPH0766156B2 (ja) ハロゲン化銀写真感光材料の製造方法
RU2045767C1 (ru) Способ изготовления аммиачной бромиодсеребряной фотографической эмульсии
JP2838533B2 (ja) ハロゲン化銀写真感光材料
EP0650084B1 (en) Silver halide photographic emulsion comprising grains having faces (100) with cavities
EP0725309A2 (en) Emulsions comprising grains with high surface to volume ratios and processes of their preparation
EP0704750A2 (en) Chemical and spectral sensitization of high-chloride tabular grains using high-temperature heat treatment
EP0618485A1 (en) Photographic product comprising a blend of emulsions with different sensitivities

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19960612

17Q First examination report despatched

Effective date: 19991025

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20000307