EP0355535A2 - Emulsions photographiques à l'halogénure d'argent - Google Patents

Emulsions photographiques à l'halogénure d'argent Download PDF

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Publication number
EP0355535A2
EP0355535A2 EP89114476A EP89114476A EP0355535A2 EP 0355535 A2 EP0355535 A2 EP 0355535A2 EP 89114476 A EP89114476 A EP 89114476A EP 89114476 A EP89114476 A EP 89114476A EP 0355535 A2 EP0355535 A2 EP 0355535A2
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EP
European Patent Office
Prior art keywords
silver
silver halide
grains
emulsion
grain
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Application number
EP89114476A
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German (de)
English (en)
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EP0355535A3 (en
EP0355535B1 (fr
Inventor
Shigeharu Urabe
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Fujifilm Holdings Corp
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Fuji Photo Film Co Ltd
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Priority claimed from JP63194862A external-priority patent/JPH0778600B2/ja
Priority claimed from JP63194861A external-priority patent/JPH0769580B2/ja
Application filed by Fuji Photo Film Co Ltd filed Critical Fuji Photo Film Co Ltd
Publication of EP0355535A2 publication Critical patent/EP0355535A2/fr
Publication of EP0355535A3 publication Critical patent/EP0355535A3/en
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    • 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
    • G03C1/0051—Tabular 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
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C1/10—Organic substances
    • G03C1/12—Methine and polymethine dyes
    • G03C1/14—Methine and polymethine dyes with an odd number of CH groups
    • G03C1/18—Methine and polymethine dyes with an odd number of CH groups with three CH groups

Definitions

  • This invention relates to a light-sensitive silver halide emulsion useful in the field of photo­graphy, and more particularly, to a silver halide photo­graphic emulsion composed of a dispersion medium and silver halide grains containing silver chloride and also to a process of producing the emulsion.
  • Silver-sensitive silver halide emulsions contain­ing silver chloride are known to give the specific advantages as shown below.
  • silver chloride is more soluble than other photographically useful silver halides, whereby the development and fixing can be achieved in a shorter time.
  • An emulsion containing silver chloride (silver chloride emulsion) has found to be particularly useful in applications requiring high contrast, such as graphic arts, and in applications requiring quick processing, such as black and white films for camera use, radiographic films, and color print products.
  • the processing time of color negative photo­graphic materials is very quickened by the C-41 process by Eastman Kodak Corporation but even in the process, it requires 17 minutes and 20 seconds in the wet processing time without including a drying step and also even in the quick process CN-16Q by Fuji Photo Film Co., Ltd., which has recently been introduced into mini-laboratory markets, it required 9 minutes and 50 seconds in processing.
  • a negative photographic film for camera use using silver iodobromide emulsions most effectively utilize the merit of silver iodide contained therein, such as high sensitivity, a double layer effect, etc., but at the same time the existence of silver iodide makes it difficult to shorten the photographic processing. That is, the iodide ions accumulated in the desilvering processing solution cause a fatal fault that the bleach and fix of silver are greatly delayed to obstruct quickening of processing and the reduction of the amounts of replenishers.
  • a silver chlorobromide emulsion is very useful for quick processing but has the disadvantages that the sensitivity is low, a chemical sensitization and a spectral sensitization are reluctant to apply to the emulsion, the sensitivity obtained by such sensitizations are unstable even when they can be applied, and fog is liable to occur.
  • Tabular grain silver halide grains (hereinafter, are referred to as "tabular grains") containing parallel twin planes have the following photographic character­istics:
  • the tabular grains have been used high speed photographic materials.
  • tabular silver bromide grains and tabular silver iodobromide grains tabular grains having an aspect ratio of at least 8 are disclosed in JP-A-58-113926, JP-A-58-113927, and JP-A-58-113928.
  • JP-A as used herein means an "unexamined published Japanese patent application”.
  • the aspect ratio is shown by the ratio of the diameter of a tabular grain to the thickness thereof.
  • the diameter of the grains means a diameter of a circle having the same area as the projected area of the grain when the grains are observed by a microscope or an electro-microscope.
  • the thickness thereof is shown by the distance between two parallel planes constituting the tabular silver halide grain.
  • U.S. Patent 4,399,215 describes that tabular silver chlorobromide grains having a silver chloride content of at least 50 mol% or tabular silver chloride grains are obtained by performing the grain formation using ammonia while keeping pAg of the system at the range of from 6.5 to 10 and pH at the range of from 8 to 10 without containing silver bromide and silver iodide in the inside thereof.
  • U.S. Patent 4,400,463 describes that a tabular silver halide emulsion having a silver chloride content of at least 50% is obtained by performing the grain formation in the co-existence of aminoazaindene and a peptizer having a thioether bond.
  • Patent 4,713,323 describes that tabular silver chloride grains or tabular silver chlorobromide grains are obtained by using a gelatin dispersion medium having a methionine content of less than 30 mole/g.
  • JP-­A-58-111936 describes that tabular silver chlorobromide grains having a mean mol ratio of chloride to bromide of at least 2/3 are obtained by double jet while keeping the mol ratio of chloride ions to bromide ions in the reaction vessel at a value of from 1.6/1 to 258/1 and also keeping the total concentration of halogen ions in the reaction vessel at a value of from 0.10 to 0.90 normal.
  • JP-B as used herein means an "examined published Japanese patent application”
  • a method of simulta­neously adding a bromide ion and a silver ion to silver halide grains having a high silver chloride content to form the layer containing more than 60 mol% of silver bromide on the surface of the grains and a method of adding halide ions as above to form wholly or partially the layer of silver bromide of from 10 to 50 mol% on the surface of the grains as described in JP-A-58-108533 and JP-A-60-222845; and a method of forming silver halide grains of multiphase structure, such as core-shell type double structure grains
  • JP-A-58-111935 discloses a photo­graphic emulsion composed of tabular silver halide grains containing 50 mol% silver chloride, which contain at least one of a bromide and an iodide in the central region thereof.
  • the topograph of the silver chloride content (or silver bromide content) of these tabular silver chloro­bromide grains can be determined by using an analytical electron microscopy.
  • the change in the halogen composition of the main surface of the tabular grain in the width direction can be observed by measuring as it is. Also, it is described in the summary of 1987 Annual Lectures, The Society of Photographic Science and Technology of Japan, by M. Inoue and T. Nagasawa, Observation of the Halogen, Distribution in Silver Halide Grains and Multilayer Structure Grains bv Analytical Electron Microscopy that as to twin or normal crystal silver chlorobromide grains having a low aspect ratio, the topography of the halogen composition can be known by analyzing the very thin cut piece thereof using an analytical electron microscopy.
  • the object of this invention is to provide a photographic emulsion composed of negative working silver halide grains giving less fog, having a high sensitivity, having improved graininess, sharpness, and covering power, and being excellent in storage stability and pressure resistance.
  • a silver halide emulsion comprising a dispersion medium and silver halide grains, wherein the silver halide grains contain at least one phase composed of two or more kinds of different silver halides, and the phase contains at least 10 mol% of silver chloride with microscopically homogeneous distribution.
  • the microscopic silver chloride distribution can be confirmed by a cooling type transmission type electron microscopy as explained in detail below, and the silver chloride-containing phase having the microscopically homogeneous silver chloride distribution disclosed by the present invention have not been obtained before the present invention.
  • JP-A-58-113927 the silver iodide distribu­tion in silver iodobromide was measured by the same manner as above but the size of the electron ray spot used was 0.2 ⁇ m.
  • the microscopic distribution of silver chloride can be observed by the direct method using a transmission type electron microscopy at low temperature described, e.g., in J.F. Hamilton, Photographic Science and Engineering , Vol. 11, 57 (1967) and Takekimi Shiozawa, Journal of the Society of Photographic Science and Technology of Japan , Vol. 35, No. 4, pp. 213 (1972). That is, silver halide grains taken from a silver halide emulsion under a safe light such that the emulsion is not printed out are placed on a mesh for electron microscopic observation and the grains are observed by a transmission method in a state of cooling the sample with liquid nitrogen or liquid helium for preventing the damage (printout, etc.) by electron beams.
  • the voltage is preferably 200 kvolts until the grain thickness of 0.25 ⁇ m and is preferably 1,000 kvolts for the grain thickness of larger than 0.25 ⁇ m. Since as the acceleration voltage is higher, the damage of the grains by the irradiation of electron beam is larger, it is preferred to cool the sample with liquid helium than by liquid nitrogen.
  • the photographing magnification for the electron microscopy can be properly selected according to the size of grains being used as the sample but is usually from 20,000 to 40,000 magnifications.
  • a very fine annular ring-form striped pattern is observed at the portion of a silver chlorobromide phase.
  • An example thereof is shown in Fig. 1 which is transmission type election microphotographs of tabular silver chlorobromide grains containing 35 mol% silver chloride.
  • Fig. 1 is transmission type election microphotographs of tabular silver chlorobromide grains containing 35 mol% silver chloride.
  • Fig. 1 a very fine annular ring-form striped pattern are clearly seen. It can be seen that the interval of the striped pattern is very fine as an order of 100 ⁇ or less, which shows very microscopic heterogeneity.
  • the very fine striped pattern shows the heterogeneity of a silver chloride distribution but it can be more directly concluded from the fact that when the tabular grains are annealed under a condition capable of transferring chlorine ions in silver halide crystals (e.g., for 3 hours at 250°C), the striped pattern completely disappears.
  • annular ring-form striped pattern described above which shows the microscopic heterogeneity of silver chloride in tabular silver halide grains containing silver chloride such as tabular silver chlorobromide grains has never been observed and has first been discovered by the inventors of the present invention.
  • the silver chlorobromide grains which are prepared for obtaining substantially homogeneous silver chloride distribution, have a very microscopic heterogeneous distribution of silver chloride completely against the intension of the production thereof and neither the technique of homogenizing the silver chloride distribution nor the production process for obtaining such silver chlorobromide grains has been disclosed.
  • the silver halide grains having the "microscopically homogeneous silver chloride distribution" in this invention can be clearly distinguished from conventional grains by observing the transmitted images of images using cooling type transmission type electron microphotography. That is, in tabular silver halide grains containing silver chloride for use in this invention, there are at most two microscopic lines caused by the microscopic heterogeneity of silver chloride in an interval of 0.2 ⁇ m, preferably one microscopic line and more preferably none.
  • the lines constituting an annular ring-form striped pattern showing the microscopic heterogeneity occur in the form of perpendicularly crossing the growing direction of the grains and these lines distribute concentrically from the center as the result thereof.
  • the lines constituting the annular ring-form striped patterns showing the heterogeneity of silver chloride perpendicularly cross the growing direction of the tabular grain, therefor the direction of the lines is parallel to the edge of the grain, the direction perpendicularly crossing the direction of the lines directs to the center of the grain, and the aforesaid lines distribute concentrically around the center of the grain.
  • the aforesaid line showing the macroscopic change of a silver chloride content is not observed since, in this case, there is no abrupt change of a silver chloride content and hence if there exist at least 3 lines within an interval of 0.2 ⁇ m, it means that there exists a microscopic heterogeneity of a silver chloride content.
  • the silver halide grains of this invention having the microscopically homogeneous silver chloride distribution are silver grains having at most 2 lines showing the microscopic silver chloride distribution within an interval of 0.2 ⁇ m in the direction of perpendicularly crossing the line in the transmitted image of the grain obtained by using a cooling type transmission electron microscopy and the silver halide grain has preferably one such line and more preferably has no such line.
  • silver halide grains in the emulsion of this invention include the aforesaid grains in a proportion of at least 40%, preferably at least 60%, and more preferably at least 80%.
  • Conventional silver halide grains which are called to be silver halide grains containing homogeneous silver chloride are those prepared by simply adding silver nitrate and a mixture of halides having a constant composition (constant iodide content) to a reaction vessel by a double jet method at the growth of the grains and in such silver halide grains, the macroscopic silver chloride distribution is surely constant but the microscopic silver chloride distribu­tion is not homogeneous.
  • the afore­said silver halide grains are called as grains having a "constant halogen composition" and are clearly distin­ guished from the silver halide grains of this invention having the "microscopically homogeneous silver chloride distribution".
  • silver chlorobromide, silver iodochloride, or silver iodochlorobromide may be used but silver chlorobromide or silver iodochloro­bromide is preferred.
  • the position of the phase containing silver chloride in the silver halide grain may be at the central portion, over the whole grain, or at outside portion(s).
  • the phase containing silver chloride may be one or plural.
  • the phase containing silver chloride frequently forms a layer structure on account of the grain growing mechanism but may form specific portion(s).
  • the silver chloride phase can be formed in the edge portions or corner portions only.
  • silver halide grains having the silver chloride phase at specific points without forming an annular structure in the grain can be formed.
  • silver iodide may be incorporated in silver chlorobromide (AgBrCl) in each layer and the coating layer containing silver iodide may be the first coating layer, the second coating layer, and/or the third coating layer.
  • silver chlorobromide AgBrCl
  • the ratio of the homogeneous silver chloride-­containing phase in one silver halide grain in this invention is generally from 5 to 99 mol%, preferably from 20 to 99 mol%, and more preferably from 50 to 99 mol%.
  • the silver chloride content in the silver chloride-containing phase of this invention is at least 10 mol% and preferably not more than 90 mol%, and more preferably from 20 mol% to 80 mol%.
  • the silver chloride content in the silver chloride-containing phase of this invention is at least 10 mol% and preferably not more than 90 mol%, and more preferably from 20 mol% to 80 mol%.
  • the sensitivity of conventional silver halide grains having the microscopically heterogeneous distribution of silver chloride is low even when a chemical sensitization is applied thereto and in particular, in the case of applying thereto sulfur and gold sensitizations, fog is liable to occur and the sensitivity is reluctant to be increased.
  • the conventional silver halide grains having "a constant silver chloride content but a microscopic heterogeneous silver chloride distribution the chemical sensitization is obstructed. Accordingly, in such conventional silver halide grains, a quick processing property which is a feature of silver chlorobromide cannot be attained.
  • silver chloride containing grains e.g., silver chlorobromide grains and silver chloroiodobromide grains
  • silver chloride containing grains showing a high development speed and a high fixing speed, which have never been attained by conventional silver chloride-containing grains, and having a high sensitivity, low fog, good graininess, and high sharpness
  • the reason why the surface of the silver halide grains having a heterogeneous silver chloride distribution disturbs the chemical sensitization thereof and the surface of the silver halide grains having the microscopically homogeneous silver chloride distribution does not disturb the chemical sensitization thereof is considered to be that since in the heterogeneous silver chloride distribution, the lattice constant on the surface of the grain crystals is not constant, the composition and the sizes of the chemical sensitizing nuclei formed thereon become varied, thereby the optimum chemical sensitization conditions cannot be obtained and on the other hand, in the case of the surface of silver halide grains having the microscopically homogeneous silver chloride distribution, the composition and the sizes of the chemical sensitization nuclei become uniform, thereby the optimum chemical sensitization can be performed. However, the real detailed reason must need further investigations.
  • the sensitivity thereof is increased if the phase is "microscopically homogeneous". That is, it is considered that if the distribution of silver chloride contained in the inside of silver halide grains is heterogeneous, the grains have many traps of electrons generated by light and the effective concentration of photoelectrons cannot be made. This matter also, however, needs further investigations.
  • the reason that the microscopic homogeneity of the silver chloride distribution in the silver halide grains containing silver chloride is important is considered to be in that the electrons generated by light are liable to move as compared to the case of heterogeneity and the concentration principle of latent images can be effectively realized.
  • the total silver chloride content in the silver halide grain of this invention is preferably from 10 to 90 mol%, more preferably at least 20 mol%, and most preferably at least 30 mol%.
  • the size of the silver halide grains having the completely homogeneous silver chloride distribution of this invention is preferably at least 0.3 ⁇ m, more preferably from 0.8 to 5 ⁇ m.
  • the form of the silver halide grains of this invention may be a regular crystal form (normal crystal grains) such as cubic, octahedral, dodecahedral, tetra­decahedral, tetracosahedral (trisoctahedron, tetrahexahedron, icositetrahedron), hexatetra­contahedral, etc., an irregular-crystal form such as spherical and potato-like, or various forms having at least one twin plane, in particular, tabular grains having parallel twin planes, e.g., hexagonal tabular grains and triangular tabular grains each having two or three twin planes.
  • regular crystal form normal crystal grains
  • normal crystal grains such as cubic, octahedral, dodecahedral, tetra­decahedral, tetracosahedral (trisoctahedron, tetrahexahedron, icositetra
  • the size of the tabular silver halide grains having the microscopically homogeneous silver chloride distribution of this invention is preferably from 0.5 to 5 ⁇ m and more preferably at least 1.0 ⁇ m, as the diameter of a circle corresponding to the mean projected area of the grains.
  • the size distribution of the tabular silver halide grains in this invention may be a mono-dispersion or a poly-dispersion but it is preferred that the silver halide grains are monodispersed grains in the form and the grain size. That is, the silver halide emulsion wherein the tabular silver halide grains having a hexagonal form with the ratio of the length of the longest side to the length of the shortest side of at most 2 and having two parallel planes as the outer surfaces account for at least 70% of the total projected area of the total silver halide grains, and further the hexagonal tabular silver halide grains are mono-­dispersed grains, as described in JP-A-63-151618, is preferred in this invention.
  • the term "monodispersed" grains or emulsion means that the coefficient of variation of the grain sizes is at most 20%, and preferably at most 15%.
  • the tabular grains of this invention are composed of parallel main surfaces each composed of a (111) plane and the aspect ratio thereof is at least 2, preferably from 3 to 20, and more preferably from 3 to 15.
  • the grain sizes are at least 0.4 ⁇ m, and preferably from 0.4 to 4 ⁇ m.
  • the silver halide photographic emulsion of the present invention preferably contains the tabular silver halide grains accounting for at least 50 % of the total projected area of silver halide grains containd in the emulsion, the mean aspect ratio of the tabular silver halide grains being at least 3.
  • the mean aspect ratio ( ⁇ ) in this invention is defined as follows:
  • D i is the diameter of a circle having the same area as the projected area of the (i)th silver halide grain
  • t i is the thickness of the (i)th grain in the direction perpendicular to the two parallel main surfaces
  • N is a number of the tabular grains necessary and sufficient for giving a mean aspect ratio of silver halide grains and N is generally more than 600.
  • the tabular silver halide grains in the emulsion of the present invention preferably have the mean aspect ratio of from 3 to 20 and more preferably from 3 to 15.
  • the production process of the silver halide grains of this invention is composed of nuclear formation and grain growth.
  • the silver halide grains which become nuclei of silver halide grains of this invention can be prepared by using the method described P. Glafkides, Chimie et Phisique Photographique (published by Paul Montel Co., 1967), G.F. Duffin, Photographic Emulsion Chemistry (published by The Focal Press, 1966), and V.L. Zelikman et al, Making and Coating Photographic Emulsion published by The Focal Press, 1964).
  • the emulsion composed of the silver halide grains can be prepared by an acid method, a neutralization method, an ammonia method, etc., and as a method of reacting a soluble silver salt and a soluble halide, a single jet method, a double jet method, or a combination of them may be employed.
  • a so-called reverse mixing method of forming silver halide grains in the existence of excessive silver ions can also be used.
  • a so-called controlled double jet method of keeping a pAg constant in a liquid phase of forming silver halide grains can also be used. According to the method, a silver halide emulsion containing silver halide grains having a regular crystal form and substantially uniform grain sizes can be obtained.
  • a mixture of two or more kinds of silver halide emulsions each formed separately can be used.
  • the halogen composition is constant, and a double jet method or a controlled double jet method is preferably employed.
  • the pAg at the preparation of the nuclei depends upon the reaction temperature and the kind of a silver halide solvent employed but is preferably from 5 to 10. Also, a silver halide solvent is preferably used and in this case, the time for forming silver halide grains can be shortened. For example, a conventional silver halide solvent such as ammonia, thioether, etc., can be used.
  • the form of the nuclei may be tabular, spherical, or twin system and also may be octahedral, cubic, tetradecahedral, or a mixed system of them.
  • the nuclei may be a poly-dispersed or mono-dispersed system but is preferably a mono-dispersed system.
  • the term "mono-dispersed" in the aforesaid case is same as defined hereinbefore.
  • each silver halide grain is uniformly coated without causing regeneration of nuclei, they can also be preferably used in the case of forming coating layer as will be explained below.
  • the aforesaid nucleus formation is carried out by adding an aqueous silver salt solution and an aqueous halide solution to a reaction vessel containing an aqueous solution of a dispersion medium while fully stirring the dispersion medium.
  • a cadmium salt, a zinc salt, a lead salt, a thallium salt, an iridium salt or the complex salt thereof, a rhodium salt or the complex salt thereof, or an iron salt or the complex salt thereof may coexist.
  • an aqueous silver salt solution and an aqueous alkali halide solution are added to the reaction vessel for growing the nuclei thus formed such that new nuclei are not formed.
  • an aqueous silver salt solution and an aqueous halide solution are added to the reaction vessel with fully stirring.
  • silver halide grains of a single halogen composition e.g., silver bromide and silver chloride
  • the silver halide phase is completely homogeneous and no microscopic heterogeneity is observed using a transmission type electron microscopy.
  • a rotary cylindrical mixer with bulging sides which has slits on the sides and is filled with an aqueous colloid solution (the mixer is preferably partitioned by a disc-­like partition on into an upper chamber and a lower chamber) is equipped to a reaction vessel filled with an aqueous colloid solution such that the rotary shaft of the mixer becomes vertical, an aqueous halide solution and an aqueous silver salt solution are supplied into the mixer rotated at high speed through supply conduits from openings formed at the upper and lower parts of the mixer, respectively, to rapidly mixing them and cause the reaction (when the mixer is partitioned into two chamber by a disc-like partition, an aqueous halide solution and an aqueous silver salt solution separately supplied into the upper and lower chambers and each diluted with the aqueous colloid solution filling each chamber and rapidly mixed near the outlet slit of the mixer to cause the reaction of the components), and the silver halide grains formed are discharged through the slits into the aqueous colloid solution (
  • JP-B-­55-10545 a technique of improving the local eviation of the concentration to prevent the occurrence of heterogeneous growth is disclosed in JP-B-­55-10545.
  • an aqueous halide solution and an aqueous silver salt solution are separately supplied to a mixer filled with an aqueous colloid solution, said mixer being equipped in a reaction vessel filled with an aqueous colloid solution, from the lower portions thereof through supply conduits, the reaction solutions are supplied and abruptly mixed by lower stirring blades (turbine blades) equipped to the mixer to grow silver halide grains, and the silver halide grains thus formed are immediately discharged into the aqueous colloid solution in the reaction vessel through upper outlet portion of the mixer by means of upper stirring blades equipped to the upper portion of the lower stirring blades.
  • the problem of causing the heterogeneity of the silver chloride distribution cannot be solved either and the formation of the annular ring-form striped pattern showing the heterogeneous distribution of silver chloride is clearly confirmed.
  • a silver halide emulsion containing fine silver halide grains (silver chlorobromide grains, silver chloroiodobromide grains, or silver iodochloride grains) having the same silver chloride content as the silver chloride content of desired silver halide grains is previously prepared and the fine grain silver halide emulsion is supplied to the reaction vessel to grow tabular grains without supplying an aqueous silver salt solution and an aqueous halide solution to the reaction vessel.
  • a mixer having a strong and efficient stirring means is disposed outside the reaction vessel, an aqueous silver salt solution, an aqueous halide solution, and an aqueous protective colloid solution are supplied to the mixer followed by quickly mixing them to form very fine silver halide grains, and the fine grains are immediately supplied to the reaction vessel.
  • an aqueous silver salt solution and an aqueous halide solution are not supplied to the reaction vessel as well as the method (1) described above.
  • U.S. Patent 2,146,938 discloses a method of forming a coarse grain silver halide emulsion by mixing fine silver halide grains having no absorbed materials with coarse silver halide grains having no adsorbed materials or by slowly adding a fine grain silver halide emulsion to a coarse grain silver halide emulsion. However, in the method, silver iodobromide only is formed.
  • JP-A-58-111936 describes "In placing of introducing a silver salt and a halide in the form of aqueous solution thereof, a silver salt and a halide can be introduced in the form of fine silver halide grains suspended in a dispersion medium at the beginning or at the growing stage.
  • the grain sizes are such that they are easily Ostwald ripening onto a larger grain nuclei which exist at the introduction of the fine grains to the reaction vessel.
  • Silver bromide grains, silver chloride grains and/or mixed silver halide grains can be introduced.”
  • the aforesaid description is a general description about the growth of silver halide grains and does not teach the specific production process and specific embodiments necessary for preparing the microscopically homogeneous silver halide grains as defined in the present invention.
  • silver halide grains becoming nuclei or core are previously placed in a reaction vessel containing an aqueous colloid solution and thereafter a previously prepared silver halide emulsion of fine grain sizes is added thereto, whereby the fine grains are dissolved by so-called Ostwald ripening and the dissolved grains are deposited on the nuclei or cores to grow silver halide grains.
  • the halide composition of the fine grain emulsion has the same silver chloride content as the silver chloride content of the desired silver halide grains and is silver chlorobromide, silver chloroiodobromide, or silver iodochloride.
  • the mean grain size is preferably not more than 0.1 ⁇ m, and more preferably from 0.001 to 0.06 ⁇ m.
  • the dissolving rate of the fine silver halide grains is important and it is pre­ ferred to use a silver halide solvent for increasing the dissolving rate.
  • a silver halide solvent there are water-soluble bromides, water-soluble chlorides, thiocyanates, ammonia, thioethers, thioureas, etc.
  • silver halide solvent examples include thiocyanates described in U.S. Patents 2,222,264, 2,448,534 and 3,320,069, ammonia, thioether compounds described in U.S. Patents 3,271,157, 3,574,628, 3,704,130, 4,297,439, and 4,276,347, thione compounds described in JP-A-53-144319, JP-A-53-82408, and JP-A-55-­77737, amine compounds described in JP-A-54-100717, thiourea derivatives described in JP-A-55-2982, imidazoles described in JP-A-54-100717, and substituted mercaptotetrazoles described in JP-A-57-202531.
  • the temperature for growing silver halide grains is at least 50°, preferably at least 60°, and more preferably at least 70°C.
  • the fine grain emulsion in the crystal growing may be added at a stretch or in divided portions but a method of supplying at a constant flow rate is preferred, and a method of increasing the addition rate is more preferred.
  • the extent of increasing the addition rate is determined by the concentration of the co-existing colloid, the solubility of the silver halide crystals, the sizes of the fine silver halide grains, the extent of stirring of the reaction vessel, the size and the concentration of the silver halide crystals existing at the time, the hydrogen ion concentration (pH) of the aqueous solution in the reaction vessel, the silver ion concentration (pAg) of the aqueous solution, etc., but simply, the extent can be determined by an ordinary experimental method.
  • the silver ions and halide ions (including chlorine ions) necessary for growing the silver halide crystals are not supplied by the addition of the aqueous solutions thereof but these ions are supplied as fine silver halide grains and the Ostwald ripening is caused by utilizing the high solubility of the fine grains to perform the growth of silver halide grains.
  • the rate-determining step of the system is not the growing step of the silver halide grains but is how fast the fine grains are dissolved to supply silver ions and halide ions in the reaction vessel.
  • the sizes of the fine grains are preferably as small as possible but, on the other hand, as the sizes of silver halide grains are smaller, the solubility thereof becomes higher, the silver halide grains become very unstable, and the grains themselves immediately cause Ostwald ripening to increase the grain sizes.
  • the mean grain size is 0.05 ⁇ m. It may be possible to obtain fine silver halide grains having a mean grain size of 0.05 ⁇ m or less, but even when such fine silver halide grains are obtained, they are unstable and the grain sizes are easily increased by Ostwald ripening. When adsorbable materials are adsorbed thereto, the occurrence of Ostwald ripening can be prevented to some extent but the dissolving rate of the fine grains is reduced by the adsorption, which is against the intension of this invention.
  • the fine grain emulsion is dissolved again and the dissolved fine grain emulsion is added to the reaction vessel containing silver halide grains becoming nuclei in the existence of a silver halide solvent to cause the growth of the silver halide grains.
  • very fine silver halide grains once formed cause Ostwald ripening in the grain growing step, a washing step, a re dispersing step, and a re-­dissolving step and the grain sizes are increased.
  • the residence time t of the solutions added to the mixer is shown by the following equiation; V: Volume (ml) of the reaction chamber of the mixer.
  • a Adding amount (ml/min.) of aqueous silver nitrate solution.
  • b Adding amount (ml/min.) of aqueous halide solution.
  • c Adding amount (ml/min.) of aqueous protective colloid solution.
  • t is not longer than 10 minutes, preferably no longer than 5 minutes, more preferably not longer than 1 minute, and most preferably from 2 to 20 seconds.
  • the fine silver halide grains formed in the mixer are thus immediately added to the reaction vessel without increasing the grain sizes.
  • the stirring blades in the reaction chamber thereof can be rotated at high rotation number, mixing by strong and efficient stirring, which has never been practiced by conventional open type reaction vessel (i.e., in an open type vessel, when stirring blades are rotated at high rotation number, the solution in the vessel is scattered away by the centrifugal force to cause foaming problem and hence such high stirring cannot be practiced), and thus the occurrence of the aforesaid coalescence ripening can be prevented, thereby fine grains having very fine grain sizes can be obtained.
  • the rotation number of the stirring blades is from 1,000 to 10,000 r.p.m., preferably at least 2000 r.p.m., and more preferably at least 3000 r.p.m.
  • the occurrence of the aforesaid coalescence ripening can be remarkably prevented by the protective colloid for fine silver halide grains.
  • the addition of an aqueous protective colloid solution to the mixer is performed by the following method.
  • the concentration of the protective colloid is from 0.2 to 10% by weight, and preferably from 0.5 to 5% by weight.
  • gelatin silver is formed by silver ions and gelatin and gelatin silver causes photodecomposition and thermal decomposition to form silver colloid.
  • the aforesaid methods i), ii), and iii) may be used solely or as combination thereof, or three methods may be used at the same time.
  • gelatin is usually used but other hydrophilic colloids can be used. Practical examples thereof are described in Research Disclosure , Vol. 176, No. 17643 (December, 1978), Paragraph IX.
  • the grain sizes of the fine silver halide grains obtained by the aforesaid techniques (a) to (c) can be confirmed by placing the grains on a mesh and measuring them by a transmission type electron microphotography of from 20,000 to 40,000 magnifications.
  • the grain sizes of the fine silver halide grains of this invention are from 0.001 to 0.06 ⁇ m, preferably from 0.005 to 0.03 ⁇ m, and more preferably not more than 0.01 ⁇ m.
  • silver halide grains of very fine grain sizes having a high dissolving rate can be supplied to a reaction vessel and hence a high growing rate of silver halide grains contained in the reaction vessel can be obtained.
  • a silver halide solvent is not inevitable in this invention but for obtaining far higher growing rate of the silver halide grains or for other purposes, a silver halide solvent may be, if necessary, used.
  • the silver halide solvent is as described above in the method (1).
  • the feeding rates of silver ions and halide ions to the reaction vessel can be freely controlled. These ions may be added to a constant rate but it is better to increasing the adding rate thereof.
  • These methods are described in U.S. Patent 3,650,757 and JP-B-52-16364. Other methods are described in the method (1).
  • the halogen composition during the growth of the silver halide grains can be freely controlled. For example, it is possible, during the growth of the silver halide grains, to keep the silver chloride content at a constant value, continuously increase or decrease the silver chloride content, or change the silver chloride content at a certain time.
  • the reaction temperature in the mixer is preferably from 0 to 60 °C, more preferably not higher than 50°C, and most preferably not higher than 40 °C.
  • gelatin is usually liable to coagulate and hence in such a case, it is preferred to use gelatin having a low molecular weight (preferably 1,000 to 30,000 in number average molecular weight).
  • Low molecular weight gelatin which is used in the aforesaid case of this invention can be usually prepared as follows. Ordinary gelatin having an average molecular weight of about 100,000 is dissolved in water and a gelatin decomposing enzyme is added thereto to enzyme-decompose the gelatin molecules. The details of the method is described in R.J. Cox, Photographic Gelatin II , pages 233-251 and pages 335-346, Academic Press, London, 1976. In this case, since the bonded positions being decomposed by enzyme are definite positions, a low molecular weight gelatin having a relatively narrow molecular weight distribution is preferably obtained. In this case, the longer the enzyme decomposition time is, the lower the molecular weight becomes. In other method of obtaining low-­molecular weight gelatin, high molecular weight gelatin is heated under the condition of low pH (pH 1 to 3) or high pH (pH 10 to 12) to hydrolyze the gelatin.
  • the production process for obtaining the tabular grains of this invention relates to the growth of tabular grains, and for the formation of nuclei, conventional technique is used.
  • the nuclei formation for tabular silver halide grains is composed of a tabular grain nucleus formation step and a ripening step. That is, as described in JP-­A-63-151618, when tabular grain nuclei are formed, other fine grains (in particular, octahedral grains and single twin grains) are simultaneously formed and by further performing ripening, other grains than the tabular grain nuclei are vanished and nuclei only becoming tabular grains can be obtained. Accordingly, in the formation of tabular grains, the nucleus formation process includes a tabular grain nuclei forming process and a ripening process.
  • the nuclear formation in the case that the nuclei are silver bromide or silver iodobromide is performed by adding an aqueous solution of a water-soluble silver salt and an aqueous solution of alkali halide(s) to an aqueous solution containing a dispersion medium while keeping pBr at from 1.0 to 2.5.
  • a tabular silver halide grain has at least one parallel twin plane in the inside thereof and the formation of the twin plane(s) is the so-called nucleus formation process.
  • the nucleus forming condition is determined by the frequency of forming the twin planes and depends upon various saturation factors (the temperature at the nucleus formation, the concentration of gelatin, the addition rates of an aqueous silver salt solution and an aqueous alkali halide solution, Br ⁇ concentration, the rotation number of stirring, the iodine content of an aqueous alkali halide solution being added, the amount of a silver halide solvent, pH, concentration of inorganic salts, etc.), which are illustrated in the figure in JP-A-63-­92942.
  • nucleus forming conditions By controlling the nucleus forming conditions, the form of nucleus grains (the number of twin planes per grain) and the grain number (determining the grain sizes after growing) can be changed.
  • nucleus formation is carried out at a temperature of from 15°C to 39°C and a gelatin concentration of from 0.05 to 1.6% by weight, nuclei having fine grains and a uniform grain size distribution can be formed.
  • a silver salt, a chloride, and a bromide are simultaneously introduced into a reaction vessel containing an aqueous solution of a dispersion medium and in this case, the mol ratio of the chloride ion/bromide ion in the reaction vessel may be maintained at from 1.6/1 to 258/1 and the total concentration of the halogen ions in the reaction vessel may be maintained at from 0.10 to 0.90 normal as shown in JP-A-58-111936.
  • U.S. Patent 4,399,215 describes that tabular silver chlorobromide grains having a silver chloride content of at least 50 mol% or tabular silver chloride grains can be obtained by performing the grain formation using ammonia without containing silver bromide and silver iodide in the inside thereof, while keeping pAg at the range of from 6.5 to 10 and pH at the range of from 8 to 10.
  • U.S. Patent 4,400,463 describes that a tabular grain silver halide emulsion having a silver chloride content of at least 50 mol% is obtained by performing the grain formation in the co-existence of aminoazaindene and a peptizer having a thioether bond.
  • U.S. Patent 4,713,323 describes that tabular grains of silver chloride or silver chloro­bromide is obtained by using gelatin having a methionine content of not more than 30 ⁇ mol/g.
  • JP-A-58-151618 fine tabular grain nuclei are formed in the nucleus formation and at the same time a large number of other fine grains (in particular, octahedral grains and single twin grains) are formed. Thus, before entering the grain growing process, it is necessary to vanish other grains than the tabular grain nuclei to obtain the grains only becoming tabular grains. For enabling the aforesaid matter, ripening is performed. Practical method for ripening is described in JP-A-58-151618.
  • magenta couplers for use in this invention there are oil-protect type indazolone series or cyanoacetyl series magenta couplers, preferably 5-­pyrazolone series magenta couplers and pyrazoloazole series magenta couplers such as pyrazolotriazole series couplers.
  • the 5-pyrazolone series couplers having an arylamino group or an acylamino group at the 3-position thereof are preferred from the viewpoint of the hue of the colored dyes and the coloring density. Typical examples thereof are described in U.S. Patents 2,311,082, 2,343,703, 2,600,788, 2,908,573, 3,062,653, 3,152,896, and 3,936,015.
  • Preferred releasing groups for the 2-equivalent 5-pyrazolone series magenta couplers include nitrogen atom-releasing groups described in U.S. Patent 4,310,619 and arylthio groups described in U.S. Patent 4,351,897. Also, 5-pyrazolone series magenta couplers having a ballast group described in European Patent 73,636 given high coloring density.
  • Pyrazoloazole series magenta couplers include pyrazolobenzimidazoles described in U.S. Patent 2,369,879, preferably pyrazolo[5,1-c][1,2,4]triazoles described in U.S. Patent 3,725,067, pyrazolotetrazoles described in Research Disclosure , No. 24220 (June, 1984), and pyrazolopyrazoles described in Research Disclosure , No. 24230 (June, 1984).
  • the aforesaid couplers may be polymer couplers.
  • imidazo[1,2-b]pyrazoles described in U.S. Patent 4,500,630 are preferred and pyrazolo[1,5-b][1,2,4]­triazoles described in U.S. Patent 4,540,654 are particularly preferred.
  • magenta couplers which can be preferably used in this invention are pyrazolo­ triazole couplers having a branched alkyl group directly bonded to the 2-, 3-, or 6-position of the pyrazolotriazole ring as described in JP-A-61-65245, pyrazoloazole couplers having a sulfonamido group in the molecule as described in J P-A-61-65246, pyrazoloazole couplers having an alkoxyphenylsulfonamide ballast group as described in JP-A-61-147254, and pyrazolotriazole couplers having an alkoxy group or an aryloxy group at the 6-position as described in European Patent (unexamined published) Application 226,849.
  • the color couplers for use in this invention are non-diffusible by having a ballast group or by being polymerized.
  • 2-equivalent color couplers having a releasing group at the coupling active position can reduce the amount of coated silver as compared with 4-equivalent color coupler having a hydrogen atom at the coupling active position.
  • Typical examples of the yellow couplers for use in this invention are oil-protect type acylacetamide type cyan couplers. Specific examples thereof are described in U.S. Patents 2,240,710, 2,875,057, and 3,265,506.
  • 2-equivalent yellow couplers are preferably used and typical examples thereof are oxygen atom-releasing type yellow couplers described in U.S. Patents 3,408,194, 3,447,928, 3,933,501, 4,022,620, etc., and nitrogen atom-releasing type yellow couplers described in JP-B-58-10739, U.S. Patents 4,401,752 and 4,326,024, Research Disclosure , No. 18053 (April, 1979), British Patent 1,425,020, West German Patent Applications (OLS) Nos. 2,219,917, 2,261,361, 2,329,587, 2,433,812, etc.
  • OLS West German Patent Applications
  • ⁇ -pivaloylacetan­ilide series yellow couplers are excellent in fastness, in particular, light fastness of the colored dyes formed, while ⁇ -benzoylacetanilide series yellow couplers give high coloring density.
  • Cyan couplers for use in this invention include oil-protect type naphtholic and phenolic couplers.
  • the naphtholic cyan couplers include naphtholic couplers described in U.S. Patent 2,474,293 and, preferably oxygen atom-releasing type 2-equivalent naphtholic couplers described in U.S. Patents 4,052,212, 4,146,396, 4,228,233 and 4,296,200.
  • specific examples of the phenolic cyan couplers are described in U.S. Patents 2,369,929, 2,801,171, 2,772,162, and 2,895,826.
  • Cyan couplers having high fastness to moisture and heat are preferably used in this invention, and typical examples thereof are the phenolic cyan couplers having an alkyl group of two or more carbon atoms at the meta-position of the phenol nucleus described in U.S. Patent 3,772,002, the 2,5-diacylamino substituted phenolic cyan couplers described in U.S. Patents 2,772,162, 3,758,308, 4,126,396, 4,334,011 and 4,327,173, West German Patent Application (OLS) No.
  • magenta couplers and other color couplers for use in this invention can be introduced into silver halide emulsions by various dispersion methods.
  • a solid dispersion method, an alkali dispersion method, and preferably a polymer dispersion method or an oil-in-water dispersion method can be used.
  • the coupler is dispersed in a high-boiling organic solvent and can be incorporated in a silver halide emulsion as the dispersion.
  • the high-boiling organic solvent shown by following formula (A) to (E) can be preferably used in this invention: W1-COO-W2 (B) W1-O-W2 (E)
  • W1, W2, and W3 each represents a substituted or unsubstituted alkyl, cyclo­alkyl, alkenyl, aryl, or heterocyclic group; W4 repre­sents W1, -OW1 or -S-W1; n represents an integer of from 1 to 5, when n is 2 or more, plural W4s may be the same or different; and in formula (E), W1 and W2 may form a condensed ring.
  • the silver halide emulsions of this invention are usually chemically sensitized.
  • chemical sensitization a conventional method can be applied and the details thereof are described at line 18 of the left lower column to line 16 of the right lower column on page 12 of JP-A-62-215272.
  • the silver halide emulsions of this invention are usually spectrally sensitized.
  • ordinary methine dyes can be used and the details thereof are described, e.g., at line 3 up of the right upper column of page 22 to page 38 of JP-A-56-215272 and Attached sheet B of the Amendment dated March 16, 1987 of the JP-A-56-215272.
  • the silver halide photographic emulsions of this invention can contain various kinds of compounds for inhibiting the formation of for during the production, storage, and photographic processing of photographic light-sensitive materials or for stabilizing the photographic performance thereof. That is, there are many compounds known as antifoggants or stabilizers, e.g., azoles such as benzothiazolium salts, nitroimid­azoles, nitrobenzimidazoles, chlorobenzimidazoles, bromobenzimidazoles, mercaptothiazoles, mercaptobenzo­ thiazoles, mercaptobenzimidazoles, mercaptothiadiazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (in particular, 1-phenyl-5-mercapto­tetrazole, etc.), mercaptopyrimidines, mercapto­triazines, etc.; thioketo compounds such as oxazoline­thione,
  • transparent supports such as polyethylene terephthalate films and cellulose triacetate films and reflective supports described below.
  • reflective supports are preferably used and examples thereof are barayta-coated papers, polyethylene-coatd papers, polypropylene series synthetic papers, vinyl chloride resin films containing a white pigment, transparent supports (e.g., glass plates, polyethylene terephthalate films, cellulose triacetate films, cellulose nitrate films, polyamide films, polycarbonate films, and polystyrene films) having thereon a reflective layer or containing therein reflective substances. They maybe properly selected according the purposes.
  • the color photographic light-sensitive material of this invention can further have a subbing layer, interlayers, protective layers, etc., in addition to the aforesaid emulsion layers.
  • gelatin is advantageously used but other hydrophilic colloids can be used.
  • gelatin limed gelatin, acid-treated gelatin and deionized gelatin as well as enzyme-treated gelatin as described in Bull. Soc. Sci. Phot. Japan , No. 16, 30(1966) can be used and also the hydrolyzed products and enzyme deposition products of gelatin can be also used.
  • the photographic light-sensitive materials of this invention may further contain hydroquinone derivatives, aminophenol derivatives, gallic acid derivatives, ascorbic acid derivatives, etc., as color fog inhibitors and specific examples thereof are described in U.S. Patents 2,360,290, 2,336,327, 2,418,613, 2,675,314, 2,701,197, 2,704,713, 2,728,659, 2,732,300, and 2,735,765, JP-A-50-92988, JP-A-50-92989, JP-A-50-93928, JP-A-50-110337, and JP-A-52-146235, and JP-B-50-23813.
  • the color photographic light-sensitive materials of this invention can further contain, if necessary, various photographic additives such as stabilizers, antifoggants, surface active agents, couplers, filter dyes, irradiation inhibiting dyes, developing agents, etc.
  • various photographic additives such as stabilizers, antifoggants, surface active agents, couplers, filter dyes, irradiation inhibiting dyes, developing agents, etc.
  • Antifungal agents are 2-thiazolylbenz­imidazoles described in JP-A-57-157244.
  • the antifungal agent may be incorporated in the photographic light-­sensitive materials or may be added thereto from outside in photographic processing steps. That is, if an antifungal agent can exist in the photographic light-­sensitive materials , the agent may be added in any optional step.
  • a color developer being used for developing the color photographic materials of this invention is preferably an alkaline aqueous solution containing an aromatic primary amino color developing agent.
  • an aromatic primary amino color developing agent aminophenol series compounds are useful but p-phenylenediamine series compounds are preferably used.
  • 3-­methyl-4 amino-N,N-diethylaniline 3-methyl-4-amino-N-­ ethyl-N- ⁇ -hydroxyethylaniline, 3-methyl-4-amino-ethyl-N-­ ⁇ -methanesulfonamidoethylaniline, 3-methyl-4-amino-N-­ethyl- ⁇ -methoxyethylaniline and the sulfates, hydrochlorides, or p-toluenesulfonates thereof. They may be used singly or as a combination of them.
  • the color developers generally contain pH buffers such as carbonates, borates or phosphates of an alkali metal and development inhibitors or antifoggants such as bromides, iodides, benzimidazoles, benzo­thiazoles, and mercapto compounds.
  • pH buffers such as carbonates, borates or phosphates of an alkali metal and development inhibitors or antifoggants such as bromides, iodides, benzimidazoles, benzo­thiazoles, and mercapto compounds.
  • the color developers may contain various preservatives such as hydroxylamine, diethylhydroxylamine, sulfites, hydrazines, phenylsemicarbazides, triethanolamine, catecholsulfonic acids, triethylenediamine(1,4-diazobi­cyclo[2,2,2]octane)s; organic solvents such as ethylene glycol, polyethylene glycol, etc.; development accelerators such as benzyl alcohol, polyethylene glycol, quaternary ammonium salts, amines, etc.; dye forming couplers, competing couplers, fogging agents such as sodium boron hydride, etc.; auxiliary developing agents such as 1-phenyl-3-pyrazolidone, etc.; tackifiers; various chelating agents such as aminopoly­carboxylic acid, aminopolyphosphonic acid, alkylphos­phonic acid, phosphonocarboxylic acid, etc.
  • preservatives such as hydroxylamine, die
  • ethylenediaminetetraacetic acid for example, ethylenediaminetetraacetic acid, nitrilotri­ acetic acid, diethylenetriaminepentaacetic acid, cyclo­hexanediaminetetraacetic acid, hydroxyethyliminodiacetic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, nitrilo-N,N,N-trimethylene phosphonic acid, ethylene­diamine-N,N,N,N-tetramethylenephosphonic acid, ethylene­diamine-di(o-hydroxy phenylacetic acid) and the salts thereof).
  • ethylenediaminetetraacetic acid for example, ethylenediaminetetraacetic acid, nitrilotri­ acetic acid, diethylenetriaminepentaacetic acid, cyclo­hexanediaminetetraacetic acid, hydroxyethyliminodiacetic acid, 1-hydroxyethyliden
  • a color development is ordinary applied after performing a black and white development.
  • black and white developing agents such as dihydroxybenzenes (e.g., hydroquinone, etc.), 3-pyrazolidones (e.g., 1-­phenyl-3-pyrazolidone, etc.), and minophenols (e.g., N-­methyl-p-aminophenol, etc.), can be used solely or as a combination thereof.
  • the amount of the replenisher for the color developer or the black and white developer depends upon the kind of the color photographic light-sensitive material being processed but is generally less than about 3 liters per square meters of the light-sensitive material and also can be reduced below 500 ml by reducing the bromide ion concentration in the replenisher. In the case of reducing the amount of the replenisher, it is preferred to prevent the evaporation and air-oxidation of the liquid by reducing the open area of the processing tank. Also, by using a means of restraining the accumulation of bromide ions in the developer.
  • the photographic emulsion layers are usually bleached and the bleach process may be performed simultaneously with or separately from a fix process. Furthermore, for quickening the photographic processing, after the blix process, a bleach process may be employed. Also, before the blix process, a fix process may be employed.
  • bleaching agent compounds of multivalent metals such as iron(III), cobalt(IV), chromium(IV), and copper(II), peracids, quinones, nitro compounds, etc.
  • Typical examples of the bleaching agents are ferricyanides, bichromates, organic complex salts of iron(III) or cobalt(III), complex salts of aminopoly­carboxylic acids such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, cyclohexanediaminetetraretic acid, methyliminodiacetic acid, 1,3-diaminopropanetetraacetic acid, glycol ether diaminetetraacetic acid, etc., or complex salts of citric acid, tartaric acid, malic acid, etc., persulfates, bromates, permanganates, nitrobenzenes, etc., can be used.
  • aminopoly­ carboxylic acid iron(III) salts such as ethylenediamine­tetraacetic acid iron(III) salt, etc., and persulfates are preferred from the viewpoints of quick processing and prevention of environmental pollution.
  • aminopolycarboxylic acid iron(III) complex salt is particularly useful in both the bleach solution and mono-bath blix solution.
  • a bleach accelerator can be, if necessary, used.
  • the useful bleach accelerator are the compounds having a mercapto group or a disulfide groups described in U.S. Patent 3,893,858, West German Patents 1,290,812 and 2,059,988, JP-A-53-­32736, JP-A-53-57831, JP-A-53-37418, JP-A-53-72623, JP-­A-53-95630, JP-A-53-95631, JP-A-53-104232, JP-A-53-­124424, JP-A-53-141623, JP-A-53 28426, Research Disclosure , No.
  • Patent 3,706,561 iodides described in West German Patent 1,127,715 and JP-A-58-­16235; polyoxyethylene compounds described in West German Patents 966,410 and 2,748,430; polyamine compounds described in JP-B-45-8836; other compounds described in JP-A-49-42434, JP-A-49-59644, JP-A-53-­ 94927, JP-A-54-35727, JP-A-55-26505, and JP-A-58-163940; and bromide ions.
  • the compounds having a mercapto group or a disulfide group are preferred from the viewpoint of giving a large acceleration effect and the compounds described in U.S. Patent 3,893,858, West German Patent 1,290,812, and JP-A-53-95630 are particularly preferred.
  • thiosulfates As a fixing agent, there are thiosulfates, thiocyanates thioether series compounds, thioureas, and a large amount of iodide but the use of a thiosulfate is general and in particular, ammonium thiosulfate is most widely used.
  • sulfites, hydrogensulfites, or cabonyl-hydrogensulfite addition product are preferably used.
  • the silver halide color photographic materials of this invention are generally subjected to a wash step and/or a stabilization step after the de-silvering process.
  • the amount of the wash water for the wash step can be selected in a wide range according to the characteristics of the light-sensitive materials (e.g., those by the materials used, such as couplers, etc.), the use thereof, the temperature of wash water, the number of wash tanks (stage number), the replenishing system such as a countercurrent system or regular system), and other various condition.
  • the relation of the number of wash tanks and the amount of wash water in a multistage countercurrent system can be obtained by the method described in Journal of the Society of Motion Picture and Television Engineers , Vol. 64, 248-253(1955, May).
  • the amount of wash water can be greatly reduced but in this case, the increase of the residence time of water in the wash tanks causes the growth of bacteria and a problem that floats formed attach to the light-sensitive materials occurs.
  • a method of reducing calcium ions and magnesium ions described in JP-A-62-­2888838 can be very efficiently used.
  • chlorine series antibacterial agents such as isothiazolone compounds described in JP-A-57-8542, cyabenzoazoles, chlorinated sodium isocyanularate, etc.; benzotriazole; and the antibacterial agents described in Hiroshi Horiguchi, Bookin Boobai Zai no Kagaku (Chemistry of Antibacterial and Antifungal Agents) , Biseibutsu no Mekkin, Sakkin, Boobai Gijutsu (Antibacterial and Anti­fungal Techniques to Microorganisms) , edited by Eisei Gijutsu Kai, and Bookin Boobai Zai Jiten (Antibacterial and Antifungal Agent Handbook) , edited by Nippon Bookin Boobai Gakkai can be also used.
  • the pH of the wash water in the processing process of the photographic light-sensitive materials of this invention is from 4 to 9, and preferably from 5 to 8.
  • the temperature of the wash water and the time for washing can be variously selected according to the characteristics and the uses of the light sensitive materials being processed but generally are from 20 seconds to 10 minutes at from 15 to 45°, and preferably from 30 seconds to 5 minutes at from 25 to 40°C.
  • a stabilization can be directly applied in place of the aforesaid wash.
  • the methods described in JP-A-­57-8543, JP-A-58-14834 and JP-A-60-220345 can be all employed.
  • a stabilization process is applied after the aforesaid wash process.
  • the stabilization bath may contain a chelating agent and an antifungal agent.
  • the overflow liquid of wash water and/or the stabilization solution upon replenishment can be reused in the de-silvering steps and other steps.
  • the silver halide color photographic materials of this invention may contain a color developing agent for simplification and quickening of processing.
  • a color developing agent for incorporating a color developing agent, it is preferred to use various precursors for color developing agents. Specific examples thereof are indoaniline compounds described in U.S. Patent 3,342,597, Schiff base type compounds described in U.S. Patent 3,342,599 and Research Disclosure No. 14850 and ibid. , No. 15159, aldol compounds described ibid. , No. 13924, metal complexes described in U.S. Patent 3,719,492, and urethane series compounds described in JP-A-53-135628.
  • the color photographic materials of this invention may contain, if necessary, various 1-phenyl-3-­pyrazolidones for accelerating color development. Typical examples thereof are described in JP-A-56-64339, JP-A-57-144547, and JP-A-58-115438.
  • the various processing solutions in this invention are used at temperature of from 10 to 50°C.
  • a temperature of from 33 to 38°C is standard but a higher temperature may be employed for accelerating processing and shortening the processing times or a lower temperature may be employed for improving the image quality and improving the stability of the processing solutions.
  • a processing process using a cobalt intensification or a hydrogen peroxide intensifi­cation described in West German patent 2,226,770 and U.S. Patent 3,674,499 may be employed.
  • heaters heat sensors, liquid level sensors, circulation pumps, filters, floating lids, squeezers, etc., may be equipped to various processing tanks.
  • a silver halide emulsion composed of silver halide grains having a mixed silver halide phase containing a silver chloride content having a microscopically homogeneous silver chloride distribution, having excellent characteristics in sensitivity, gradation, graininess, sharpness, resolving powder, covering power, storage stability, latent image stability, and pressure resistance, and showing high developing speed and fixing speed, thereby capable of performing quick processing.
  • the resulting emulsion was cooled to 35°C, washed by an ordinary flocculation method, and after adding thereto 70 g of gelatin, the pH and pAg thereof were adjusted to 6.2 and 7.8, respectively.
  • the grains formed were octahedral silver chlorobromide grains having a mean grain size of 1.5 ⁇ m and a silver chloride content of 40 mol%.
  • Emulsion 1-B After following the same procedure as the case of preparing Emulsion 1-B to provide a silver halide emulsion of silver chlorobromide grains having a mean grain size of 0.3 ⁇ m in a reaction vessel, the fine grain emulsion 1-A (having a silver chloride content of 40 mol%) dissolved at 75°C was added to the reaction vessel by a pump. The addition rate was such that the fine grain emulsion was added in an amount as calculated as silver nitrate of 150 g over a period of 100 minutes. In this case, 20 g of sodium chloride was previously dissolved in the fine grain emulsion. Thereafter, the emulsion obtained was washed as in the preparation of Emulsion 1 B and the pH and pAg thereof were adjusted to 6.5 and 7.8, respectively at 40°C.
  • the grains obtained were octahedral silver chlorobromide grains having a mean grain size of 1.5 ⁇ m and a silver chloride content of 40 mol%.
  • the growth of the feed crystals was performed as follows. As shown in Fig. 2, 800 ml of an aqueous solution containing 150 g of silver nitrate, 800 ml of an aqueous solution containing 63 g of potassium bromide and 43 g of sodium chloride, and 800 ml of an aqueous solution of 10% by weight gelatin were added to a mixer having strong and efficient stirring blades disposed near the reaction vessel by a triple jet method over a period of 100 minutes. The very fine grains (mean grain size of 0.02 ⁇ m) thus formed were immediately introduced into the reaction vessel continuously. During the step, the temperature of the mixer was kept at 25°C and the temperature of the reaction vessel was kept at 75°C.
  • Emulsion 1-B washed with water as in Emulsion 1-B, and the pH and pAg thereof were adjusted to 6.5 and 7.8, respectively at 40°C.
  • the grains thus obtained were octahedral silver chloride grains having a mean grain size of 1.5 ⁇ m and a silver chloride content of 40 mol%.
  • Sensitizing Dye 1 150 mg/mol-Ag of Sensitizing Dye 1 shown below was added to each emulsion at 60°C and after 10 minutes, each of Emulsions 1-B, 1-C, and 1-D was most suitably chemically sensitized by sodium thiosulfate, potassium chloroaurate, and potassium thiocyanate. Sensitizing Dye 1:
  • a coating composition for a surface protective layer was prepared by successively adding the following components (1) to (5) with stirring at 40°C.
  • the emulsion coating composition and the coating composition for surface protective layer thus obtained were coated on a cellulose triacetate film support by a simultaneous extrusion coating method at 103/45 by volume ratio.
  • the silver coverage was 3.1 g/m2.
  • the sample After applying a wedge exposure to the sample for 1/10 second at 200 lux by a light source of a color temperature of 2854°K, the sample was developed by following developer D-1 for 7 minutes at 20°C, fixed by the following fix solution F-1, washed, and dried.
  • the emulsion was washed by an ordinary flocculation method and after dissolving 20 g of gelatin in the emulsion, the pH thereof was adjusted to 6.5.
  • the mean size of the fine silver chlorobromide grains (silver chloride content of 50 mol%) thus obtained was 0.08 ⁇ m.
  • an aqueous solution of 20% sodium chloride was added thereto using the above-prepared grains as cores and thereafter, an aqueous solution of 100 g of silver nitrate and an aqueous solution containing 35 g of potassium bromide and 22.2 g of sodium chloride were immediately added thereto by a double jet method over a period of 70 minutes.
  • the emulsion was cooled to 35°C, washed by an ordinary flocculation method, and the pH and pAg thereof were adjusted to 6.2 and 8.1, respectively at 40°C.
  • the silver halide grains were octahedral grains having a mean grain size of 1.0 ⁇ m, wherein the core was silver bromide and the shell was silver chlorobromide containing 50 mol% silver chloride.
  • the grains formed were octahedral grains having a mean grain size of 1.0 ⁇ m, wherein the core was silver bromide and the shell was silver chlorobromide having a silver chloride content of 50 mol%.
  • the grain growth was performed as follows. That is, an aqueous solution containing 100 g of silver nitrate, an aqueous solution containing 35 g of potassium bromide and 22.2 g of sodium chloride, and an aqueous solution of 3% by weight gelatin (bone gelatin, mean molecular weight 100,000) were added to a mixer having a strong and efficient stirring means disposed near the reaction vessel as shown in Fig. 2 by a triple jet method over a period of 70 minutes. The very fine grains (mean grain size 0.01 ⁇ m, silver chlorobromide containing a silver chloride content of 50 mol%) were immediately and continuously added to the reaction vessel containing the core grains from the mixer. The temperature of the mixer was kept at 25°C. Thereafter, the emulsion formed was washed as in the case of Emulsion 2-C and the pH and pAg thereof were adjusted to 6.2 and 8.1, respectively at 40°C.
  • the grains obtained were octahedral grains having a mean grain size of 1.0 ⁇ m, wherein the core was silver bromide and the shell was silver chlorobromide containing 50 mol% silver chloride.
  • Sensitizing Dye 2 After most suitably sensitizing each of Emulsions 2-B, 2-C, and 2-D thus obtained with sodium thiosulfate, chloroauric acid, and potassium thiocyanate at 60°C, following Sensitizing Dye 2 was added such that the amount became 50 mg/mon-Ag. Sensitizing Dye 2:
  • Each of multilayer color photographic materials (Samples 301 to 303) having the layers of the following compositions on a cellulose triacetate film support having subbing layer was prepared.
  • the coating amount was shown by a g/m2 unit of silver with respect to silver halide and colloid silver, by a g/m2 unit with respect to coupler, additives, and gelatin, and a mol number per mol of silver halide in the same layer with respect to sensitizing dye.
  • the chemical structures the chemical names of the compounds used are shown later.
  • Layer 1 Antihalation layer Black Colloid Silver 0.2 Gelatin 1.3 Colored Coupler C-1 0.06 Ultraviolet Absorbent UV-1 0.1 Ultraviolet Absorbent UV-2 0.2 Dispersion Oil Oil-1 0.01 Dispersion Oil Oil-2 0.01
  • Layer 2 Interlayer Fine Grain Silver Chloride (mean grain size 0.07 ⁇ m) 0.15 Gelatin 1.0 Colored Coupler C-2 0.02 Dispersion Oil Oil-1 0.1
  • Layer 3 First Red-sensitive Emulsion Layer Emulsion (mean grain size 0.4 ⁇ m; AgBrCl (silver chloride 35 mol%)) 1.0-silver Sensitizing Dye I 1.5 ⁇ 10 ⁇ 4 Sensitizing Dye II 3.5 ⁇ 10 ⁇ 4 Sensitizing Dye III 1.5 ⁇ 10 ⁇ 5 Coupler C-3 0.48 Coupler C-4 0.48 Coupler C-8 0.08 Coupler C-2 0.08 Dispersion Oil Oil-1 0.30 Dispersion Oil Oil-3 0.04
  • Samples 301 to 303 were prepared. Table 3 Sample 301 Sample 302 Sample 303 Layer 4 [Emulsion (1)] 1-B 1-C 1-D Layer 7 [Emulsion (2)] 1-B 1-C 1-D Layer 10 [Emulsion (3)] 1-B 1-C 1-D
  • each emulsion was most suitably chemically sensitized for fitting each emulsion layer.
  • each sample was processed by the following process at 38°C. Color Development 2 min. 15 sec. Bleach 6 min. 30 sec. Wash 2 min. 10 sec. Fix 4 min. 20 sec. Wash 3 min. 15 sec. Stabilization 1 min. 05 sec.
  • compositions of the processing solutions used for the process were as follows. Color Developer Diethylenetriaminepenttaacetic Acid 1.0 g 1-Hydroxyethylidene-1,1-diphosphonic Acid 2.0 g Sodium Sulfite 4.0 g Potassium Carbonate 30.0 g Potassium Bromide 1.4 g Hydroxylamine sulfate 2.4 g 4-(N-Ethyl-N- ⁇ -hydroxyethylamino)-2-methylaniline Sulfate 4.5 g Water to make 1.0 liter pH 10.0 Bleach Solution Ethylenediaminetetraacetic Acid Ferric Ammonium Salt 100.0 g Ethylenediaminetetraacetic Acid Di-sodium Salt 10.0 g Ammonium Bromide 150.0 g Ammonium Nitrate 10.0 g Water to make 1.0 liter pH 6.0 Fix Solution Ethylenediaminetetraacetic Acid Di-sodium Salt 1.0 g Sodium Sulfite 4.0
  • the emulsions of this invention give remarkably high sensitivity as compared to the comparison emulsion.
  • Oil-1 Tricresyl Phosphate Oil-2 Dibutyl Phthalate Oil-3 Bis(2-ethylhexyl) Phthalate Sensitizing dye I Sensitizing dye II Sensitizing dye III Sensitizing dye IV Sensitizing dye V Sensitizing dye VI
  • the tabular silver bromide grains for nuclei (hereinafter, is referred to as seed crystals) thus formed were washed by an ordinary flocculation method and the pH and pAg thereof were adjusted to 6.0 and 8.5, respectively at 40°C.
  • the diameter of the circle corresponding to the mean projected area of the tabular grains obtained was 0.4 ⁇ m.
  • the emulsion was cooled to 35°C, washed by an ordinary flocculation method, and the pH and pAg thereof were adjusted to 6.5 and 8.0, respectively at 40°C.
  • the grain obtained were tabular silver chlorobromide grains having a diameter of the circle corresponding to the mean projected area thereof of 2.0 ⁇ m and a mean thickness of 0.32 ⁇ m, wherein the outside of the core had 60 mol% silver bromide and 40 mol% silver chloride.
  • the solution After dissolving 1/10 by weight of the seed crystal emulsion 4-A in one liter of an aqueous solution of 3% by weight gelatin, the solution was kept at 75°C. Thereafter, after adding thereto 30 ml of an aqueous solution of 20% sodium chloride and 0.5 g of 3,6-­dithioctane-1,8-diol, the dissolved fine grain emulsion 1-A in Example 1 was immediately added thereto by a pump. In this case, the fine grain emulsion was added over a period of 100 minutes so that the amount became 150 g as silver nitrate calculated. In this case, 10.4 g of sodium chloride was previously dissolved in the fine grain emulsion.
  • Emulsion 4-B washed as in the case of Emulsion 4-B and the pH and pAg thereof were adjusted to 6.5 and 8.0, respectively at 40°C.
  • the diameter of the circle corresponding to the mean projected area of the tabular grains was 2.1 ⁇ m and the thickness of the tabular grains was 0.31 ⁇ m.
  • the emulsion was prepared by following the same procedure as Emulsion 4-B except the following procedure.
  • the grain growth was performed as follows. An aqueous solution containing 150 g of silver nitrate, an aqueous solution containing 63 g of potassium bromide and 31 g of sodium chloride, and an aqueous solution of 10% by weight low molecular weight gelatin (mean molecular weight of 10,000) were added to a mixer having strong and efficient stirring means disposed near the reaction vessel as shown in Fig. 2 by a triple jet method over a period of 100 minutes. The very fine grains formed in the mixer (mean grain size 0.02 ⁇ m) were immediately introduced into the reaction vessel containing seed crystals from the mixer. During the step, the mixer was kept at 27°C.
  • Emulsion 4-B washed as in Emulsion 4-B and the pH and pAg thereof were adjusted to 6.5 and 8.0, respectively at 40°C.
  • the diameter of the circle corresponding to the mean projected area of the tabular grains was 2.1 ⁇ m and the mean thickness of the grains was 0.32 ⁇ m.
  • the emulsion was prepared by following the same procedure as Emulsion 4-B except that the addition of 3,6-dithioctane-1,8-diol was omitted.
  • the mean circle-corresponding diameter of the tabular grains formed was 2.3 ⁇ m and the mean thickness thereof was 0.27 ⁇ m.
  • the emulsion was prepared by following the same procedure as Emulsion 4-D except that the addition of 3,6-dithioctane-1,8-diol was omitted.
  • the mean circle-corresponding diameter of the tabular grains obtained was 2.2 ⁇ m and the mean thickness thereof was 0.27 ⁇ m.
  • the fine grains added were only partially dissolved and the fine grains left after finishing the addition thereof.
  • Emulsions 4-B, 4-C, 4-D, 4-E, and 4-F thus obtained was sampled and the transmitted images thereof were observed by a transmission type electron microscope of 200 Kvolts in a state being cooled by liquid nitrogen.
  • the results showed that in Emulsions 4-B and 4-E, a clear annular ring-like striped pattern (8 lines in 0.2 ⁇ m interval) was observed but in Emulsions 4-C, 4-D, and 4-F of this invention, no such striped pattern was observed.
  • tabular silver chlorobromide emulsion having the microscopically homogeneous silver halide distribution was obtained.
  • Emulsion 4-C shows that in the method of adding the previously prepared fine grain emulsion, the mean size of fine grains 1-A is 0.09 ⁇ m and for dissolving the grains, a silver halide solvent is necessary (in this case, the solvent is 3,6-dithioctane-1,8-diol).
  • the solvent is 3,6-dithioctane-1,8-diol.
  • the use of such a silver halide solvent is not required since the sizes of the fine grains are very fine, thereby an emulsion having small thickness of grains and hence having a high aspect ratio and a narrow grain size distribution is obtained.
  • the aforesaid method can give the microscopically homogeneous silver chloride distribution and is an ideal growing method of tabular silver halide grains.
  • the emulsion was most suitably chemically sensitized at 60°C. After finishing the chemical sensitization, 4-hydroxy-6-­methyl-1,3,3a,7-tetraazaindene was added to the emulsion, and the emulsion was coated on a polyethylene terephthalate film support at a silver coverage of 3 g/m2.
  • Example 2 After exposing each sample to blue light using a tungsten light source of 2854°K and an interference filter of 419 nm for 1/10 second, the sample was developed and fixed as in Example 2 and then washed and dried.
  • the pBr thereof was adjusted to 2.5 by adding an aqueous solution of 1.0M silver nitrate and thereafter, an aqueous solution of 150 g of silver nitrate was added at an accelerated flow rate (the flow rate at the end thereof was 10 times that of the beginning) over a period of 60 minutes while simultaneously adding thereto an aqueous solution of potassium bromide by a double jet method such that pBr was kept at 2.5.
  • the emulsion was cooled to 35°C, washed with an ordinary flocculation method, and after adding thereto 60 g of gelatin and dissolving at 40°C, the pH and pAg thereof were adjusted to 6.5 and 8.7, respectively.
  • the tabular silver bromide grains formed were mono-dispersed tabular grains having a mean circle-­corresponding diameter of 2.2 ⁇ m, a grain thickness of 0.18 ⁇ m and a variation coefficient of the circle-­corresponding diameters of 18%.
  • Emulsion 5-A containing silver bromide corresponding to 100 g as silver nitrate in one liter of water After dissolving Emulsion 5-A containing silver bromide corresponding to 100 g as silver nitrate in one liter of water, the temperature of the solution was raised to 70°C and after adding thereto 50 ml of an aqueous solution of 20% sodium chloride, an aqueous solution containing 50 g of silver nitrate and an aqueous solution containing 17.5 g of potassium bromide and 13 g of sodium chloride were immediately added thereto by a double jet method over a period of 100 minutes.
  • the emulsion was cooled to 35°C, washed by an ordinary flocculation method, and pH and pAg thereof were adjusted to 6.5 and 8.1 at 40°C.
  • the grains thus formed were tabular silver chlorobromide grains having a diameter of the circle corresponding to the mean projected area of 2.4 ⁇ m and the mean thickness of 0.22 ⁇ m, the outside of core being composed of 50 mol% silver bromide and 50 mol% silver chloride.
  • Emulsion 2-A in Example 2 After dissolving Emulsion 2-A in Example 2 corresponding to 100 g as silver nitrate in one liter of water, the temperature of the solution was raised to 70°C. After adding thereto 50 ml of an aqueous solution of 20% by weight sodium chloride, fine grain emulsion 2-­A dissolved at 40°C was immediately added thereto by a pump. The fine grain emulsion was added over a period of 100 minutes such that the amount thereof became 50 g as silver nitrate calculated. In this case, 4.4 g of sodium chloride was previously added to the fine grain emulsion. Thereafter, the emulsion was washed as in Emulsion 4-B and pH and pAg thereof were adjusted to 6.5 and 8.1, respectively, at 40°C.
  • the diameter of the circle corresponding to the mean projected area of the tabular grains was 2.3 ⁇ m and the mean thickness of the grains was 0.24 ⁇ m.
  • the emulsion was prepared by the same manner as Example 4-B except the following procedure.
  • the grain growth was performed as follows. An aqueous solution containing 50 g of silver nitrate, an aqueous solution containing 35 g of potassium bromide and 13 g of sodium chloride, and an aqueous solution of 3% by weight of gelatin (bone gelatin, mean molecular weight 100,000) were added to a mixer having strong and efficient stirring means disposed near the reaction vessel as shown in Fig. 2 by a triple jet method over a period of 100 minutes.
  • gelatin bone gelatin, mean molecular weight 100,000
  • the very fine grains (mean grain size 0.02 ⁇ m, silver bromide 50 mol%, silver chloride 50 mol%) formed in the mixer were immediately introduced into the reaction vessel containing seel grains from the mixer.
  • the temperature of the mixer was kept at 25°C. Thereafter, the emulsion was washed as in Emulsion 4-B and the pH and pAg thereof were adjusted to 6.5 and 8.1, respectively.
  • the diameter of the circle corresponding to the mean projected area of the tabular grains formed was 2.4 ⁇ m and the mean thickness thereof was 0.22 ⁇ m.
  • each of the emulsions 5-B, 5-C, and 5-D thus obtained was sampled and the transmitted images were observed by a transmission type electron microscope of 200 Kvolts in a state being cooled by liquid nitrogen as in Example 4. There emulsions were clearly confirmed by the transmitted images of the grains that the core was composed of AgBr and the shell was composed of silver chlorobromide (silver content 50 mol%).
  • Emulsion 5-­B an annular ring-like striped pattern (8 lines in 0.2 ⁇ m interval) was clearly observed but in the grains of the emulsions 5-C and 5-D of this invention, the striped pattern was not observed and it can be seen that by the present invention, a tabular grain silver chlorobromide emulsion having the microscopically homogeneous silver chloride distribution was obtained.
  • Sensitizing Dye 2 in Example 2 was added thereto at 200 mg/mol Ag.
  • the emulsion was coated on a polyethylene terephthalate film support at a silver coverage of 2 g/m2.
  • the emulsions of this invention have a higher sensi­tivity than the comparison emulsion with same fog.
  • the temperature thereof was raised to 70°C and 32 ml of an aqueous solution containing 2M of silver nitrate and 32 ml of an aqueous solution containing 1.2M of potassium bromide and 1.8M of potassium chloride by a double jet method over a period of 80 minutes.
  • the emulsion was cooled to 35°C, washed by an ordinary flocculation method, and after adding thereto 60 g of gelatin and dissolving at 40°C, the pH and pAg thereof were adjusted to 6.5 and 7.8, respectively.
  • the tabular silver chlorobromide grains were grains having a mean circular corresponding diameter of 2 ⁇ m and a mean grain thickness of 0.2 ⁇ m, wherein the silver chloride content of the core was 15 mol% and the silver chloride content of the shell was 40 mol%.
  • Emulsion 6-A The emulsion was washed as in Emulsion 6-A and the pH and pAg thereof were adjusted to 6.5 and 7.8, respectively at 40°C.
  • the diameter of the circle corresponding to the mean projected area of the tabular grains was 2.2 ⁇ m and the mean grain thickness was 0.3 ⁇ m.
  • the emulsion was prepared as in Example 6-B except the following procedure.
  • the grain growth was performed as follows. That is, 320 ml of an aqueous solution of 2M of silver nitrate, 320 ml of an aqueous solution containing 1.2M of potassium bromide and 1.8M of potassium chloride, and 500 ml of an aqueous solution of 10% by weight low molecular weight gelatin (mean molecular weight 5,000) were added to a mixer having strong and efficient stirring means disposed near the reaction vessel as shown in Fig. 2 by a triple jet method. The very fine grains (mean grain size 0.01 ⁇ m, silver bromide 60 mol%, silver chloride 40 mol%) formed in the mixer were immediately and continuously introduced into the reaction vessel containing seed grains from the mixer. The mixer was kept at 15°C.
  • Emulsion 4-A The emulsion was washed as in Emulsion 4-A and the pH and pAg thereof were adjusted to 6.5 and 7, respectively.
  • the diameter of the circle corresponding to the mean projected area of the tabular grains was 2.2 ⁇ m and the mean grain thickness was 0.3 ⁇ m.
  • Emulsions 6-A, 6-B and 6-C thus obtained were sampled and the transmitted images thereof were observed by a transmission type electron microscope of 200 Kvolts in a state being cooled by liquid nitrogen.
  • the results showed that in Emulsion 6-A, a clear annular ring-like striped pattern (6 lines in 0.2 ⁇ m interval) was observed but in Emulsions 6-B and 6-C of this invention, no such striped pattern was observed.
  • tabular silver chlorobromide emulsion having the microscopically homogeneous silver halide distribution was obtained.
  • Example 1 After finishing the chemical sensitization, the emulsion coating composition and the coating composition for protective layer were coated as in Example 1 to provide each sample. Each sample was exposed, developed, fixed, washed and dried as in Example 1.
  • the emulsions of this invention have remarkable high sensitivity and low fog as compared to the comparison emulsion. Furthermore, the emulsions of this invention had high gradation as compared with the comparison emulsion.
  • Multilayer color photographic materials were prepared by following the same procedure as Example 3 except that Emulsions (1), (2), and (3) of Layers 4, 7, and 10 were changed as shown in Table 8.
  • Table 8 Sample 701 Sample 702 Sample 703 Sample 704 Sample 705 Layer 4 (Emulsion 1) 4-B 4-D 6-A 6-B 6-C Layer 7 (Emulsion 2) 4-B 4-D 6-A 6-B 6-C Layer 10 (Emulsion 3) 4-B 4-D 6-A 6-B 6-C Samples 701 and 703: Comparison samples Samples 702, 704, and 705:Samples of Invention
  • each emulsion was most suitable chemically sensitized for meeting each emulsion layer.
  • the emulsions of this invention have high sensitivity as compared with the comparison emulsions.

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EP19890114476 1988-08-04 1989-08-04 Emulsions photographiques à l'halogénure d'argent Expired - Lifetime EP0355535B1 (fr)

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JP63194862A JPH0778600B2 (ja) 1988-08-04 1988-08-04 ハロゲン化銀写真乳剤
JP194862/88 1988-08-04
JP63194861A JPH0769580B2 (ja) 1988-08-04 1988-08-04 ハロゲン化銀写真乳剤
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5320938A (en) * 1992-01-27 1994-06-14 Eastman Kodak Company High chloride tabular grain emulsions and processes for their preparation
EP0374852B1 (fr) * 1988-12-19 1998-03-25 Fuji Photo Film Co., Ltd. Procédé pour former des grains à l'halogénure d'argent

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1472745A1 (de) * 1965-03-09 1972-02-03 Agfa Gevaert Ag Verfahren zur Herstellung von Silberhalogenid-Dispersionen
DE3241645A1 (de) * 1981-11-12 1983-06-01 Eastman Kodak Co., 14650 Rochester, N.Y. Strahlungsempfindliche photographische silberhalogenidemulsion und verfahren zur herstellung derselben

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1472745A1 (de) * 1965-03-09 1972-02-03 Agfa Gevaert Ag Verfahren zur Herstellung von Silberhalogenid-Dispersionen
DE3241645A1 (de) * 1981-11-12 1983-06-01 Eastman Kodak Co., 14650 Rochester, N.Y. Strahlungsempfindliche photographische silberhalogenidemulsion und verfahren zur herstellung derselben

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0374852B1 (fr) * 1988-12-19 1998-03-25 Fuji Photo Film Co., Ltd. Procédé pour former des grains à l'halogénure d'argent
US5320938A (en) * 1992-01-27 1994-06-14 Eastman Kodak Company High chloride tabular grain emulsions and processes for their preparation

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EP0355535A3 (en) 1990-03-07
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EP0355535B1 (fr) 1994-10-26

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