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
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
• • 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
  • G03C1/015—Apparatus or processes for the preparation of 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
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
  • G03C7/3022—Materials with specific emulsion characteristics, e.g. thickness of the layers, silver content, shape of AgX grains

Definitions

• This invention relates to photographic silver bromoiodide emulsions, photographic elements incorporating these emulsions, and processes for the use of the photographic elements.
• Photographic emulsions useful in photography typically comprise a dispersing medium, such as gelatin, containing grains of photographic silver halide.
• Emulsion other than silver bromoiodide have found only limited use in camera speed photographic elements.
• Silver bromoiodide emulsions and their preparation are described in, for example, such standard texts as Duffin, "Photographic Emulsion Chemistry", Focal Press, 1966 and Mees and James, "The Theory of the Photographic Process", MacMillan Publishing Co., 4th Edition, 1977.
• Photographic silver bromoiodide emulsions having various grain sizes and shapes are also known in photography.
• Illustrative emulsions containing silver bromoiodide grains are described in, for example, European Patent Application 330,508 and U.S. Patents 4,433,048; 4,720,452; 3,505,068 and 4,704,351.
• Photographic silver bromoiodide emulsions that contain octahedral silver bromoiodide grains are also known, such as described in U.S. Patents 4,150,994; 4,184,877 and 4,610,958 and published Japanese Patent Application (Kokai) 60-138538 published July 23, 1985.
• Such silver bromoiodide emulsions may be comprised of a core covered by one or more shells of the same or differing silver halides.
• Such core-shell emulsions may have a uniform iodide content or may have a varying iodide concentration in its core and/or shell(s).
• Such an emulsion with a varying iodide content is described in EP-A-0 428 041. This document falls within the terms of Article 54(3) EPC.
• Octahedral silver bromoiodide emulsions are known to have advantages, such as high sensitivity and improved photographic properties.
• advantages such as high sensitivity and improved photographic properties.
• a photographic silver bromoiodide emulsion comprising a dispersing medium and silver bromoiodide that (a) is octahedral silver bromoiodide; (b) has a grain size within the range of 0.45 to 1.2 ⁇ m; (c) contains 1 to 12 mole percent iodide; (d) has a core region (A), a surface region (B) and a subsurface region (C) between core region (A) and surface region (B); wherein (i) subsurface region (C) contains an iodide concentration higher than the iodide concentration of core region (A) and which is made by the method of the present invention.
• a method of preparing an octahedral silver bromoiodide emulsion wherein the octahedral silver bromoiodide grains have a grain size within the range of 0.45 to 1.2 ⁇ m; contain 1 to 12 mole percent iodide; and have a core region (A), a surface region (B) and a subsurface region (C) wherein the subsurface region (C) between core region (A) and surface region (B) contains an iodide concentration higher than the iodide concentration of each of core region (A) and surface region (B); wherein the process comprises, in sequence:
• the octahedral silver bromoiodide grains that result from the described process are preferably monodispersed grains having a grain size within the range of 0.6 to 1 ⁇ m.
• the step (III) is described herein as a "dump iodide step".
• the method steps as described enable the formation of a higher concentration of crystal defects in the silver bromoiodide than would otherwise be expected. This higher concentration of crystal defects is believed to contribute to the unexpectedly higher photographic speed of the resulting octahedral silver bromoiodide as described.
• the silver bromoiodide emulsions prepared by the method of the present invention may be coated on a support to form a photographic element, particularly a color photographic element, comprised of a support bearing said emulsion.
• a visible photographic image may be produced in such photographic elements, particularly a color photographic image, by a process comprising processing an exposed photographic element, as described herein in an aqueous alkaline solution in the presence of a photographic developing agent, particularly a color photographic silver halide developing agent.
• the presently prepared emulsions enable unique and unexpected advantages. They enable the improvement of photographic speed and reduced granularity without sacrificing the advantages of an octahedral silver bromoiodide emulsion.
• the described emulsions are particularly advantageous when chemically sensitized and spectrally sensitized and in color photographic materials designed to form dye images.
• the emulsions enable significantly improved photographic speed for color images, especially images that have particularly useful sharpness and speed-grain relationship.
• octahedral herein includes octahedral and such grains that do not include sharp edges, such as cubooctahedral grains.
• core region (A) herein means the central portion of the octahedral silver bromoiodide grain according to the invention.
• This region (A) can contain 0 to 9 mole percent iodide. It comprises 50% to 90%, typically 60% to 80% by weight of the total silver bromoiodide grain.
• surface region (B) herein means the outer region of the octahedral silver bromoiodide beyond subsurface region (C).
• This region (B) can contain 0 to 9 mole percent iodide. This typically comprises 10% to 40% by weight of the total silver bromoiodide grain.
• subsurface region (C) herein means the region of the silver bromoiodide grain according to the invention between the core region (A) and the surface region (B) as described.
• the subsurface region (C) typically comprises 1% to 20% by weight of the total silver bromoiodide grain.
• the interfaces between the regions (A), (B) and (C) as described are typically not sharply defined in the silver bromoiodide grain.
• Each of the regions (A), (B) and (C) may, but typically do not, comprise multiple regions within each of the described regions, that is each region does not typically comprise multiple shells.
• the step (IV) can be essentially eliminated or extended depending on the emulsion making equipment capability.
• the hold step (IV) is present and is typically carried out within a period of about 2 minutes to 10 minutes.
• finishing step is preferably carried out using at least one spectral sensitizing dye as part of the finishing step. Any spectral sensitizing dye known to be useful in a finishing step can be used for this purpose.
• a finishing modifier known in the photographic art in the finishing step such as a benzothiazolium finish modifier.
• Such a finishing step using at least one spectral sensitizing dye and a finish modifier, such as a benzothiazolium compound enables the resulting photographic silver bromoiodide emulsion of the invention to have even higher photographic speed than otherwise would be expected.
• the term monodispersed herein means that at least 95%, such as 95% to 99.9%, by weight of the silver bromoiodide grains less than the mean grain diameter and at least 95%, such as 95% to 99.9%, by number of the silver bromoiodide grains larger than than the mean grain diameter must be within 40% of the mean grain diameter.
• the mean grain diameter means the diameter of a circle equal in area to the mean projected area of the silver bromoiodide grains, especially as viewed in a photomicrograph or an electronmicrograph of an emulsion sample.
• the octahedral silver bromoiodide grains as described may have rounded corners and rounded edges.
• the grain size and characteristics of the silver bromoiodide grains as described can be readily ascertained by procedures well known in the photographic art. In some instances a concentration of silver halide grains that are not octahedral silver bromoiodide grains can be present in the emulsion and element without adversely affecting the required properties of the silver bromoiodide emulsion as described.
• the silver bromoiodide emulsion as described is prepared by controlling the introduction of the iodide salts in the precipitation process.
• the iodide is added in the process within a reasonably short time and can be termed a "dump iodide process" because the iodide is not run into the reaction mixture over the entire term of the precipitation.
• the described step (III) is a "dump iodide step".
• a dispersing medium preferably an aqueous gelatin or gelatin derivative composition
• the volume of dispersing medium initially present in the reaction vessel can equal or exceed the volume of the silver bromoiodide emulsion present in the reaction at the conclusion of the grain precipitation.
• the dispersing medium introduced into the reaction vessel is preferably a dispersion of peptizer in water, particularly gelatin in water, optionally containing other ingredients, such as silver halide ripening agents and/or metal dopants.
• the peptizer particularly gelatin or a gelatin derivative, is typically initially present in a concentration of at least 0.5%, preferably at least 1%, of the total peptizer present at the completion of the silver bromoiodide precipitation.
• Additional dispersing medium can optionally be added to the reaction vessel with the silver salts and the alkali metal bromide and iodide salts and also can be introduced through a separate inlet means, such as a separate jet. The proportion of dispersing medium can be adjusted after the completion of the salt introductions or after washing.
• silver salts preferably silver nitrate, bromide salts, preferably alkali metal bromide salts, and iodide salts, preferably alkali metal bromide salts, are added to the reaction vessel by techniques known in the photographic emulsion making art.
• an aqueous silver salt solution preferably an aqueous silver nitrate solution
• the bromide and iodide salts are typically introduced as aqueous solutions, preferably as aqueous solutions of one or more alkali metal, such as potassium or sodium salts.
• Alkaline earth metal salts can also be useful, such as calcium and magnesium salts.
• the silver salt is introduced into the reaction vessel separately from the halide salt.
• the iodide and bromide salts can be added to the reaction vessel separately or as a mixture.
• the nucleation step of the grain formation is initiated.
• a population of grain nuclei are formed that are capable of serving as precipitation sites for silver bromide and silver iodide as the introduction of silver, bromide and iodide salts continues.
• the precipitation of the silver bromide and silver iodide onto the existing grain nuclei constitutes the crystal growth step of grain formation.
• the permissible latitude of pBr during the growth stage of the precipitation is within the range of 1.75 to 4.2 pBr, preferably within the range of 2.0 to 2.8 pBr.
• the pBr can be measured and regulated during the precipitation by methods and apparatus known in the photographic art.
• the pBr is as defined in U.S. Patent 4,434,226 and is the negative logarithm of bromide ion concentration.
• the concentrations and rates of silver salt, bromide salt and iodide salt introductions can take any convenient and conventional form useful for forming octahedral silver bromoiodide emulsions.
• the silver and halide salts are preferably introduced in concentrations within the range of 0.1 to 5 moles per liter.
• the rate of silver and halide salt introduction can be constant or optionally increased either by increasing the rate at which the silver and halide salt are introduced or by increasing the concentrations of the silver and halide salts being introduced. It is preferred to increase the rate of silver and halide salt introduction, but to maintain the rate of introduction below that at which the formation of new grain nuclei is favored to avoid renucleation.
• the concentration of iodide in each step is important to enable the higher concentration of iodide in subsurface region (C) as described.
• the process can be carried out within controlled pAg conditions using methods and apparatus known in the photographic art.
• the vAg is, for example, controlled within the range of +5 to +160 mV, preferably within the range of +20 to +80 mV.
• the process of preparing the described silver bromoiodide is preferably carried out at a temperature within the range of 25°C to 80°C, such as 45°C.
• Modifying compounds can be present during the silver bromoiodide precipitation. Such compounds can be initially in the reaction vessel or can be added with one or more of the salts according to conventional emulsion making procedures. Modifying compounds, such as compounds of copper, iridium, thallium, lead, bismuth, cadmium, zinc, middle chalcogens, such as sulfur, selenium and tellurium, gold, Group VIII noble metals, can be present during the precipitation, as described in, for example, U.S. Patent 4,433,048 and the art described therein.
• the individual silver and halide salts or a silver halide source can be added to the reaction vessel through surface or subsurface delivery tubes, by gravity feed or delivery apparatus for maintaining control of the rate of delivery and the pH, pBr, and/or pAg or the reaction vessel contents as is used in the art of photographic emulsion making.
• a dispersing medium preferably comprises in the reaction vessel initially an aqueous peptizer suspension.
• the peptizer concentration is typically within the range of 0.2% to 10% by weight, based on the total weight of the emulsion components in the reaction vessel.
• concentration of peptizer in the reaction vessel is maintained below about 6%, based on the total weight, prior to and during silver halide formation.
• the emulsion vehicle concentration is typically adjusted upwardly for optimum coating characteristics by delayed, supplemental vehicle additions. Additional vehicle can be added later to bring the concentration up to as high as 1000 grams per mole of silver halide.
• the concentration of vehicle in the finished emulsion is above 50 grams per mole of silver halide.
• the vehicle preferably comprises about 30% to about 70% by weight of the emulsion layer.
• Vehicles including both binders and peptizers, can be selected from those conventionally employed in photographic silver halide emulsions.
• Preferred peptizers are hydrophilic colloids, that can be used alone or in combination with hydrophobic materials.
• Useful hydrophilic materials include both naturally occurring substances, such as proteins, protein derivatives, cellulose derivatives, such as cellulose esters, gelatin, such as alkali treated gelatin or acid treated gelatin, gelatin derivatives, such as acetylated gelatin and phthalated gelatin, polysaccharides, such as dextran, gum arabic, zein, casein, pectin, collagen derivatives, agar-agar, arrowroot and albumin and other vehicles and binders known in the photographic art. Gelatin is highly preferred.
• hydrophilic colloid peptizers as vehicles, including, for example, vehicle extenders such as materials in the form of latices, are also useful in the emulsions as described, such as polymeric peptizers, carriers and/or binders, such as poly(vinyl lactams), acrylamide polymers, poly(vinyl alcohol) and its derivatives, poly(vinyl acetals), polymers of alkyl and sulfoalkyl acrylates and methacrylates, hydrolyzed poly(vinyl acetates), polyamides, poly(vinyl pyridine), acrylic acid polymers, maleic acid copolymers, vinyl amine copolymers, methacrylic acid copolymers, acryloyloxyalkylsulfonic acid copolymers, sulfoacrylamide copolymers, polyalkyleneimine copolymers, polyamines, N,N-dialkylaminoalkyl acrylates,
• the vehicles and binders including the hydrophilic colloids, as well as the hydrophobic materials, can be employed alone or in combination, not only in the emulsion layers of the photographic element, but also can be used alone or in combination in other layers, such as overcoat layers, interlayers, and layers positioned between emulsion layers and the support.
• Grain ripening can be carried out in preparation of an emulsion as described.
• Grain ripening agents known to be useful in the photographic art can be useful in the photographic emulsions.
• a thioether ripening agent can be added to the photographic silver bromoiodide emulsion.
• Useful thioether ripening agents include, for example, those described in U.S. Patents 3,271,157; 3,574,628; and 3,737,313.
• the silver bromoiodide emulsions are preferably washed to remove soluble salts. Any of the processes and compositions known in the photographic art for this purpose can useful for washing the photographic silver bromoiodide emulsions.
• the soluble salts can be removed by decantation, filtration, and/or chill setting and leaching, coagulation washing, by centrifugation, and by other methods and means known in the photographic art.
• the silver bromoiodide emulsion as described can be blended or otherwise combined with other photographic silver halide emulsions.
• the octahedral photographic silver bromoiodide emulsions can be, for example, optionally combined with a tabular grain silver halide emulsion, such as one described in U.S. Patent 4,433,048, or optionally combined with a cubic grain silver halide emulsion, such as one described in European Patent Application No. 353,628.
• the photographic silver bromoiodide can be chemically sensitized by procedures and by compounds known in the photographic art to be useful for this purpose.
• the silver bromoiodide can be chemically sensitized with active gelatin, or with sulfur, selenium, tellurium, gold, platinum, palladium, iridium, osmium, rhodium, rhenium, or phosphorous sensitizers or combinations of these sensitizers, such as at pAg levels within the range of 90 to 120 mV and pH levels within the range of 5 to 8 at temperatures within the range of 30° to 80°C.
• the silver bromoiodide can be chemically sensitized in the presence of finish, also known as chemical sensitization, modifiers, such as compounds known to suppress fog and increase speed during chemical sensitization, such as azaindenes, azapyridazines, azapyrimidines, benzothiazolium salts, and sensitizers having more than one heterocyclic nuclei.
• the silver bromoiodide can be reduction sensitized, such as with hydrogen, or through the use of reducing agents, such as stannous chloride, thiourea dioxide, polyamines or amineboranes.
• the photographic silver bromoiodide emulsion can be spectrally sensitized by methods and compounds known in the photographic art.
• the silver halide emulsion can be sensitized in the presence of sensitizing dyes.
• the photographic silver bromoiodide emulsion can be spectrally sensitized by, for example, dyes of a variety of classes, including the polymethine sensitizing dye class, including cyanines, merocyanines, complex cyanines and merocyanines, oxonols, hemioxonols, styryls, merostyryls and streptocyanines. Combinations of spectral sensitizers are also useful.
• the photographic silver bromoiodide emulsions can be used in ways, in photographic element formats and for purposes that silver bromoiodide emulsions have been used in the photographic art.
• Photographic silver halide elements comprising a photographic silver bromoiodide emulsion as described can be either single color or multicolor elements.
• a cyan dye-forming coupler is typically associated with a red-sensitive emulsion
• a magenta dye-forming coupler is typically associated with a green-sensitive emulsion
• a yellow dye-forming coupler is associated with a blue-sensitive emulsion.
• Multicolor elements typically contain dye-forming units sensitive to each of the three primary regions of the spectrum. Each unit can comprise a single emulsion layer or multiple emulsion layers. The layers of the element and the image-forming units can be arranged in various orders as known in the photographic art.
• the photographic element can contain added layers, such as filter layers, interlayers, overcoat layers, subbing layers and other layers known in the photographic art.
• Silver halide emulsions that can be employed in combination with the silver bromoiodide emulsion as described can be comprised of silver bromide, silver chloride, silver iodide, silver chloroiodide, silver chlorobromide or mixtures thereof. These silver halide emulsions can include silver halide grains of any conventional shape or size. Specifically the emulsions can be coarse, medium or fine grain. Tabular grain silver halide emulsions are particularly useful in a photographic element as described. The silver halide emulsions that are useful with the silver bromoiodide emulsions can be polydisperse or monodisperse as precipitated.
• the grain size distribution of these emulsions can be controlled by silver halide grain separation techniques or by blending silver halide emulsions of differing grain sizes. For example, silver bromoiodide or silver bromides of different sizes of the same type and shape can be blended.
• any coupler known in the photographic art can be used with the silver bromoiodide emulsions as described.
• Examples of useful couplers are described in, for example, Research Disclosure Section VII, paragraphs D, E, F, and G and in U.S. Patent 4,433,048 and the publications cited therein, as well as in U.S. Patents 4,333,999; 4,443,536; 4,420,556; 4,401,752; 4,777,121; 4,728,598; 4,753,871; 4,782,012; 4,477,563; 4,248,962; 4,409,323 and European Patent Applications 284,239; 271,323; 271,324; 285,274; 193,389; 255,085 and 284,240.
• Polymeric couplers are also useful with the described silver bromoiodide emulsions, as described in, for example, U.S. Patents 4,804,620; 4,540,654; and 4,576,910.
• the couplers can be incorporated as described in Research Disclosure Section VII and the publications cited therein.
• the photographic emulsions and elements can contain addenda known to be useful in the photographic art.
• the photographic emulsions and elements can contain brighteners (Research Disclosure Section V), antifoggants and stabilizers (Research Disclosure Section VI), antistain agents and image dye stabilizers (Research Disclosure Section VII, paragraphs I and J), light absorbing and scattering materials (Research Disclosure Section VIII), hardeners (Research Disclosure Section XI), plasticizers and lubricants (Research Disclosure Section XII), antistatic agents (Research Disclosure Section XIII), matting agents (Research Disclosure Section XVI) and development modifiers (Research Disclosure Section XXI).
• the photographic emulsions can be coated on a variety of supports as described in, for example, Research Disclosure Section XVII and the references cited therein.
• the photographic elements as described can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image as described in Research Disclosure Section XVII and then processed to form a visible image using processes and compositions known in the photographic art, such as described in Research Disclosure Section XIX and U.S. Patent 4,433,048 and the references described therein.
• Processing of a color photographic element as described to form a visible dye image includes the step of contacting the element with a color photographic silver halide developing agent to reduce developable silver halide and oxidize the color developing agent. Oxidized color developing agent in turn reacts with at least one coupler to yield a dye.
• Preferred color developing agents are p-phenylenediamines.
• 4-amino-3-methyl-N,N-diethylaniline hydrochloride 4-amino-3-methyl-N-ethyl-N- ⁇ -(methanesulfonamido)ethylaniline sulfate hydrate; 4-amino-3-methyl-N-ethyl-N- ⁇ -hydroxyethylaniline sulfate; 4-amino-3- ⁇ -(methanesulfonamido)ethyl-N,N-diethylaniline hydrochloride and 4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluene sulfonic acid.
• this processing step leads to a negative image.
• this step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but not form dye, and then uniform fogging of the element to render unexposed silver halide developable.
• a photographic silver bromoiodide emulsion and element as described, a photographic silver halide development inhibitor releasing compound or coupler (DIR compound or DIAR compound).
• Any development inhibitor releasing compound or coupler known in the photographic art is useful with the photographic silver bromoiodide emulsion and element.
• Particularly useful development inhibitor releasing compounds or couplers are represented by the formula: CAR-TIME-INH wherein CAR is a carrier moiety, preferably a coupler moiety; TIME is at least one timing group; and INH is a development inhibitor moiety.
• DIR compounds that satisfy the formula CAR-TIME-INH are known in the art and are described in, for example, U.S. Patents 4,248,962; 4,409,323; 4,684,604; 4,737,451; 4,546,073; 4,564,587; 4,618,571; 4,698,297; 4,782,012; and U.K Patent 2,099,167 and European Published Patent Applications 167,168 and 255,085 and German OLS 3,307,506, the disclosures of which are incorporated herein by reference.
• the carrier moiety (CAR) can be any moiety that, as a result of reaction with oxidized color developing agent, will release the timing group (TIME).
• TIME timing group
• the carrier is a coupler, but it can be another group, such as a hydrazide, a hydrazine or hydroquinone.
• Coupler moieties can be colored or colorless, diffusible or nondiffusible, reaction product with oxidized color developing agent.
• the DIR compounds are DIR couplers represented by the formula: COUP-TIME-INH wherein COUP is a coupler moiety.
• the development inhibitor that is released from the DIR compound or coupler during processing of the element can be any of the development inhibitors known in the photographic art.
• Illustrative INH moieties are mercaptotetrazoles, selenotetrazoles, mercaptobenzolthiazoles, selenobenzothiazoles, selenobenzimidazoles, mercaptobenzimidazoles, mercaptobenzoxazoles, selenobenzoxazoles, benzotriazoles, and benzodiazoles. Particularly preferred are those described in U.S. Patents 4,477,563 and 4,782,012.
• Emulsions A and B are comparison emulsions and emulsions C and D are examples of the invention.
• Emulsion A - (Iodide introduced uniformly throughout the precipitation)
• a monodisperse, octahedral grain, silver bromoiodide (3M% I) emulsion having a grain size of 0.8 ⁇ m was prepared in the following manner:
• Solution 1A (Placed in the reaction vessel)
• Solution 1A To Solution 1A, at 80°C, were added 0.018 g of 1,10-dithio-4,7,13,16-tetraoxacyclooctadecane dissolved in 36 ml of methanol and distilled water (1:1). The pH of the contents of the reaction vessel was determined to be 5.22, and the pBr was adjusted to 2.8 using a 1M sodium bromide solution. Solutions 2A and 4A were then simultaneously run into Solution 1A, with continuous agitation, for 5 minutes using a balanced double jet technique at a flow rate of 15 ml per minute, while maintaining the pBr at 2.8 and the temperature at 80°C. At this point Solution 7A was added and the resulting composition was held for 5 minutes.
• Emulsion B - (All of the iodide was introduced uniformly throughout the first 80% of the precipitation, followed by only bromide for the last 20%)
• Solution 1B To Solution 1B, at 80°C, were added 0.018 g of 1,10-dithio-4,7,13,16-tetraoxacyclooctadecane dissolved in 36 ml of methanol and distilled water (1:1). The pH of the contents of the reaction vessel was determined to be 5.17, and the pBr was adjusted to 2.8 using a 1M solution of sodium bromide. Solutions 2B and 5B were then simultaneously run into Solution 1B, with continuous agitation, for 5 minutes using a balanced double jet technique at a flow rate of 0.5 ml per minute, while maintaining the pBr at 2.8 and the temperature at 80°C. At this point Solution 8B was added and the resulting composition was held for 5 minutes.
• Emulsion C - (All of the iodide was introduced at one finite time during the precipitation)
• the pH of the reaction vessel was determined to be 5.82, and the pBr was adjusted to 2.8 using a 1M solution of sodium bromide. Solutions 2C and 5C were then simultaneously run into Solution 1A in the reaction vessel, with constant agitation. The addition was performed over a 5-minute period, using a balanced double jet technique at a flow rate of 24 ml per minute while maintaining the pBr at 2.8 and the temperature at 80°C. The precipitation was then stopped and Solution 9C was added and the reaction vessel and the resulting composition was held for 5 minutes. At 2 1/2 minutes into the hold the pBr was adjusted to 2.2 with Solution 2C.
• Solutions 2C and 5C were then introduced using flow rates of 24 ml per minute for 10 minutes, 40 ml per minute for 10 minutes, 65 ml per minute for 10 minutes, 105 ml per minute for 10 minutes and 155 ml per minute until Solution 6C was exhausted while maintaining a pBr of 2.2.
• Solution 4C was then dumped into the reaction vessel and the resulting composition was held for 2 minutes, at which time Solution 8C was dumped into the reaction vessel and the composition was again held for 2 minutes.
• Solution 7C was then introduced at a flow rate of 77 ml per minute for 10 minutes, then 33 ml per minute until a pBr of 2.5 was reached.
• the emulsion was then cooled to 40°C and washed using by diafiltration, with a semipermeable membrane to a pBr of 3.5.
• Solution 10C was then added and the pH and pBr were adjusted to 5.6 and 3.4 respectively.
• the emulsion had a grain size of 0.7 ⁇ m.
• Emulsion D - (The introduction of the iodide was partly accomplished in a uniform manner during the run phase of the precipitation and partly during a finite time in the precipitation)
• Emulsion was prepared using the same procedure described above for Emulsion C with the following differences in composition of the solutions:
• the emulsion had a grain size of 0.6 ⁇ m.
• the series of monodisperse octahedral grain silver bromoiodide emulsions described above were spectrally sensitized to the red region of the visible spectrum then optimally sulfur and gold chemically sensitized in the presence of sodium thiocyanate and the finish modifier N-[N-(methyl-sulfonyl)carbamoylethyl]benzothiazoliumtetrafluoroborate.
• the emulsions were separately coated in a single-layer cyan dye-forming format on a cellulose triacetate film support.
• Each of the coated elements comprised the respective emulsion at 0.8 g Ag/m, gelatin at 3.2 g/m, a solvent dispersion of the cyan dye image-forming coupler (Coupler A) at .97 g/m and the DIR coupler (Coupler B) at 0.03 g/m.
• An overcoat layer comprising gelatin at 4.3 g/m and the hardener bis(vinylsulfonylmethyl)ether at 1.75% based on the 5 total gelatin weight was applied.
• the resulting photographic elements were imagewise exposed at 1/100 of a second through a 0 - 4.0 density step tablet plus a Wratten No. 29 filter (Wratten is a trademark of Eastman Kodak Co., U.S.A.) to a 600W, 5500 K tungsten light source. Processing was accomplished at 37.7°C in a color process of the type described in the British Journal of Photography Annual 1979, pages 204 -206, at a development time of 3 minutes 15 seconds. The processed photographic elements were then evaluated for speed and relative granularity position. The results are given in following Table I: TABLE I Element/Emulsion (Grain Size) ⁇ Log E vs.

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• 1990
  • 1990-11-08 CA CA 2029579 patent/CA2029579A1/en not_active Abandoned
  • 1990-12-06 DE DE1990627009 patent/DE69027009T2/de not_active Expired - Fee Related
  • 1990-12-06 EP EP19900203208 patent/EP0432834B1/en not_active Expired - Lifetime
  • 1990-12-13 JP JP2401967A patent/JP2909220B2/ja not_active Expired - Fee Related

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