JPS6343733B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to improvements in silver halide photographic emulsions having epitaxial hybrid silver halide crystals. More specifically, the present invention relates to a silver halide photographic emulsion that has excellent storage stability and is less likely to cause pressure fog. Techniques for combining halides to take advantage of the strengths of individual silver halides within a single silver halide grain structure are known in the art. For example, British Patent No. 1027146 discloses hybrid silver halide grains in which a silver halide core (core grain) is coated with one or several adjacent layers of silver halide; Depositing silver on the surface of silver bromide provides the spectral sensitivity of silver bromide and the development properties of silver chloride. Furthermore, U.S. Patent No. 3,505,068 discloses a technique of creating a slow emulsion layer that is used together with a fast emulsion layer using the technique of the British patent mentioned above, thereby obtaining a low contrast of a dye image. The silver halide grains used in slow emulsions have a core of silver iodide or silver iodohalide and a shell of silver bromide, silver chloride or silver chlorobromide. Further, German Patent No. 505012 describes the preparation of silver halide photographic emulsions which have a green tone when developed by precipitating silver halide under conditions in which potassium iodide and sodium chloride are continuously added. A technology that can do this has been disclosed. Furthermore, U.S. Patent No. 3,656,962;
No. 3852066 and No. 3852067 disclose a technique for changing the sensitivity to light by adding an inorganic crystalline substance to a silver halide emulsion, thereby creating a close physical bond between the silver halide grains and the inorganic crystalline substance. . On the other hand, a silver halide photographic emulsion having a hybrid silver halide crystal in which the radiation sensitivity of silver iodide and the rapid developability of silver chloride are epitaxially bonded has recently been developed. This epitaxial hybrid silver halide crystal is composed of a polyhedral crystal of silver iodide and a silver chloride crystal formed by epitaxial bonding to this polyhedral crystal, as disclosed in JP-A-53-103725, etc. At least half of the silver iodide crystal planes are substantially free of epitaxial silver chloride, and the silver chloride is limited to 75 mol % or less of the total mixed silver halide. Silver halide photographic emulsions containing epitaxy-hybridized silver halide crystals can liberate relatively large amounts of iodide ions when developed, and thus achieve favorable photographic effects due to the liberation of iodide ions. A major feature is that it is possible to Furthermore, other characteristics of this silver halide photographic emulsion are that it exhibits favorable interimage and edge effects, and upon development produces a heterogeneous catalytic image, i.e., a silver image, which is used in redox amplification reactions. It is possible to obtain photographic images of both a silver image and a dye image with small graininess and granularity, and furthermore, it is possible to develop photographic images with both silver chloride and silver iodide. The ability to selectively develop images allows for controlling the graininess of photographic images,
Development conditions can be selected to control the release of iodide ions or to control the maximum density obtained. However, silver halide photographic emulsions containing mixed silver halide crystals with epitaxially bonded silver chloride have the drawbacks of decreased sensitivity and occurrence of fog when stored, as well as the occurrence of pressure fog. There are also some drawbacks. In addition, in connection with the technique described in JP-A-53-103725, there is a technique for replacing silver chloride epitaxially bonded to a silver iodide polyhedral crystal as a crystal substrate with silver bromide by a conversion method. , U.S. Patent No.
Disclosed in No. 4142900. This technique is noteworthy as it solves the development speed by using epitaxially bonded silver halide crystals, and has various advantages similar to those described for the technique of JP-A-53-103725. However, since this technology relies on the conversion method, it has the drawbacks of being prone to pressure fog due to crystal lattice defects or structural distortions, and lack of storage stability. It is the same as the silver chloride-silver iodide crystal. Therefore, the object of the present invention is to
(hereinafter referred to as Document 1) and U.S. Patent No.
4142900 (hereinafter referred to as Document 2), a silver halide having epitaxial hybrid silver halide crystals that has excellent storage stability and does not cause pressure fog. An object of the present invention is to provide a photographic emulsion. The above-mentioned objects of the present invention and other objects to be described later are a polyhedral crystal of silver iodide and a crystal of silver chlorobromide formed by epitaxy bonding to the polyhedral crystal by the method shown in [A] or [B] below. has a hybrid silver halide crystal consisting of, and at least half of the polyhedral crystal faces of the silver iodide are substantially free of epitaxial silver chlorobromide, and the silver chlorobromide accounts for 75% of the entire mixed silver halide. A silver halide photographic emulsion characterized in that the silver halide photographic emulsion is mol % or less. [A] A method of epitaxially bonding a silver chlorobromide crystal to a polyhedral silver iodide crystal by simultaneously mixing a solution containing water-soluble chloride and water-soluble bromide with a silver salt solution. [B] A silver chloride crystal is epitaxially bonded to a silver iodide polyhedral crystal, and the silver chloride crystal is attached to (a). Simultaneous mixing method of a solution containing water-soluble bromide and a silver salt solution,
or (b). A method of epitaxially bonding silver bromide or silver chlorobromide crystals by simultaneously mixing a solution containing water-soluble chloride and water-soluble bromide with a silver salt solution. achieved by. In this specification, "epitaxy" has the same meaning as the term described in Documents 1 and 2. In other words, it is a term used for mixed silver chloride-silver iodide crystals, mixed silver chlorobromide-silver iodide crystals, etc., and the term refers to crystals of silver atoms and chloride atoms or chlorobromide atoms, etc. of these crystals. This means that the crystallographic orientation of halide atoms bonded to a substrate is controlled by a crystal such as silver iodide, which is a crystal substrate, during their growth. The epitaxial relationship between epitaxial silver halide such as silver chloride or silver chlorobromide in a hybrid crystal and the epitaxial portion of silver halide as a crystal substrate such as silver iodide is different from that of silver iodide, silver chloride, etc. This is completely different from direct physical contact with crystals of silver, silver chlorobromide, etc. One of the major features of the present invention is that the silver chlorobromide crystal epitaxially bonded to the polyhedral crystal of silver iodide as a crystal substrate has [A] a polyhedral crystal of silver iodide containing water-soluble chloride and a water-soluble [B] A method of epitaxially bonding a silver chloride crystal to a polyhedral crystal of silver iodide by simultaneously mixing a solution containing a polyhedral bromide and a silver salt solution; In the crystal of (a). Simultaneous mixing method of a solution containing water-soluble bromide and a silver salt solution,
or (b). Points formed by any of the following methods: epitaxy bonding of silver bromide or silver chlorobromide crystals by simultaneous mixing of a solution containing water-soluble chloride and water-soluble bromide with a silver salt solution. It is in.
That is, the method is to form a mixed silver chlorobromide-silver iodide crystal without using the conversion method shown in Document 2. Epitaxial silver chlorobromide in the present invention is understood in relation to silver iodide as a crystal substrate. That is, in the case of the method [A] above, the silver chlorobromide crystal is directly epitaxy bonded to the polyhedral crystal of silver iodide, and in the case of (a) of the above [B], the silver iodide crystal is directly epitaxially bonded to the polyhedral crystal of silver iodide. Since a silver bromide crystal is epitaxially bonded to a silver chloride crystal which is epitaxially bonded to a polyhedral crystal of Also, in the case of (b) in [B] above, as in the case of (a) above, the crystals of silver chloride and silver chlorobromide that are epitaxially joined are: It has an epitaxial relationship with silver iodide as a crystal substrate.
As described above, the epitaxial silver chlorobromide of the present invention is in an epitaxial relationship with silver iodide as a crystal substrate by either method [A] or [B]. The present inventors epitaxially bonded silver chlorobromide to a silver iodide polyhedral crystal as a crystal substrate by a method including the simultaneous mixing method of [A] or [B], The storage stability of a photographic emulsion containing silver oxide-silver iodide crystals was significantly improved, and the occurrence of pressure fog was successfully prevented. In other words, the various drawbacks of the techniques of Documents 1 and 2 are solved at once. The silver iodide as the substrate crystal of the present invention is polyhedral radiation-sensitive silver iodide, at least in part of which has a minimum average grain size of at least 0.1 micron. This polyhedral crystal of silver iodide is formed by epitaxially bonding crystals of silver chlorobromide by a method including the simultaneous mixing method described in [A] or [B]. At least half of the polyhedral crystal faces of this silver iodide are substantially free of epitaxial silver chlorobromide, and the silver chlorobromide is limited to 75 mol % or less of the total mixed silver halide. The silver halide photographic emulsion containing the epitaxial hybrid silver halide crystals of the present invention can liberate a relatively large amount of iodide ions when developed, and the photographic effects due to the liberation of iodide ions can be improved. advantageous to achieve. The photographic emulsions according to the invention exhibit favorable interimage and edge effects. For example, it is used in the redox amplification reaction between an oxidizing agent (cobalt hexamine, hydrogen peroxide, etc.) and a dye image-forming reducing agent (such as a color developing agent or a redox dye releasing agent used with an electron transfer agent). Iodide ions released during the development step can be used in the present invention to render the surface of such heterogeneous catalysts inert. The photographic emulsion of the present invention can be coated as a silver halide emulsion layer on a suitable support, dried, imagewise exposed to radiation in the visible spectrum, and developed under suitable development conditions. A silver image is obtained. Also, under redox amplification reaction conditions, iodide ions released during development can be used to inactivate the silver image as a redox amplification catalyst. Further, the photographic emulsion according to the present invention has the advantage that both a silver image and a dye image can be obtained by containing a dye-forming coupler, and these images have small graininess and granularity. Further, the photographic emulsion according to the present invention can be selectively developed, such as by developing silver chlorobromide or by developing both silver chlorobromide and silver iodide. Therefore,
The photographic emulsion according to the present invention has advantages such as being able to control the graininess and granularity of the photographic image, controlling the release of iodide ions, or selecting development conditions to control the maximum density of the resulting image. . The present invention will be explained in further detail below. The photographic emulsion according to the present invention contains mixed crystals of silver iodide and silver chlorobromide. A portion of each hybrid crystal is a normal silver iodide crystal, and a β-phase silver iodide crystal having a truncated double pyramid crystal type is preferably used as the silver iodide crystal. The silver iodide crystal used as the crystal substrate used in the present invention is detailed in References 1 and 2, and the silver iodide of the present invention preferably has a minimum average grain size of at least 0.2μ. used. Further, the second part of each hybrid crystal, that is, the part formed by epitaxy bonding to the polyhedral crystal of silver iodide as a crystal substrate by the method including the simultaneous mixing method of [A] or [B] above. is a cubic silver chlorobromide crystal. This epitaxially bonded silver chlorobromide crystal is also described in detail in Document 2, and the present invention has substantially the same structure as that described in Document 2. The specific structure of the epitaxial hybrid crystal contained in the photographic emulsion according to the present invention is considered to be as follows. That is, as detailed in Document 2, the hybrid crystal of the present invention is composed of a truncated hexagonal double pyramid type β-phase silver iodide crystal and a cubic silver chlorobromide crystal, The silver bromide crystal forms an epitaxial junction with the silver iodide crystal as a crystal substrate. A specific epitaxial junction configuration diagram is shown in FIG. 4 in Document 2, and a diagram of a modification thereof is shown in FIG. 3 in the same document. In the present invention, the structural diagram when silver chlorobromide is epitaxially bonded to a polyhedral crystal of silver iodide by the method [B] above is the same as the simultaneous mixing method shown in Example 1 of Reference 1 or the same method. A silver chloride crystal is epitaxially bonded to a silver iodide crystal as shown in FIG. 4 or 3 of Document 1 by a positive mixing method as shown in Example 9 of Document 2 or Example 1 of Document 2. Further, cubic silver bromide crystals or silver chlorobromide crystals are formed on the silver chloride crystals of this mixed silver chloride-silver iodide crystal, and this silver chloride and silver bromide or silver chlorobromide crystals are is considered to form an epitaxial junction surface. In the epitaxial hybrid crystal used in the present invention, the silver iodide crystal portion acts as a first radiation receptor. Imagewise exposure of blue light to a photographic emulsion containing the hybrid crystals of this invention forms a developable latent image. When the epitaxial hybrid crystal of silver iodide and silver chlorobromide of the present invention is exposed to light, the entire hybrid silver halide crystal becomes developable, but only the silver chlorobromide portion can be developed. In the hybrid crystal used in the present invention, at least half of the polyhedral crystal faces of silver iodide are free of epitaxial silver chlorobromide, and the epitaxial silver chlorobromide is typically one, two, or two of the silver iodide crystals. Sometimes limited to three sides. In addition, in the hybrid crystal used in the present invention, silver chlorobromide accounts for 75 mol% of the total mixed silver halide.
Limited to: When silver chlorobromide reaches 75 mol%, the silver chlorobromide crystal structure on the surface of the adjacent silver iodide crystal plane erodes the silver iodide crystal plane where epitaxial growth of silver chlorobromide begins. . The epitaxial silver chlorobromide in the hybrid crystal of the present invention is not the first radiation receptor of the hybrid crystal.
Therefore, the photographic speed of the photographic emulsion according to the present invention is not controlled by the radiation impinging on the epitaxy silver chlorobromide. The high photographic speeds of the photographic emulsions of the present invention are due to the specific combination of silver halides and the restriction of silver chlorobromide crystals forming hybrid crystals. The amount of epitaxial silver chlorobromide in the hybrid crystal of the present invention is desirably 1 to 50 mol% of the total hybrid silver halide, more preferably its minimum content is 5 mol%. This epitaxy silver chlorobromide has the effect of accelerating the initial development rate. The optimum amount of epitaxial silver chlorobromide of the present invention is determined depending on the intended use of the photographic emulsion of the present invention, and for example, when a high level of radiation exposure and high development speed are required. A higher proportion of epitaxial silver chlorobromide is used for the lower radiation exposure level and slower development characteristics. Further, depending on the size of the crystal used in epitaxy silver chlorobromide, it can be controlled so that the silver iodide crystal as a crystal substrate is not developed and the epitaxy silver chlorobromide is developed. In this case, the graininess and granularity of the photographic image is determined by the limited size (diameter) of the epitaxy silver chlorobromide crystals (provided there is no solution physical development). Also, these photographic speeds are determined by silver iodide crystals as larger crystalline substrates. The photographic emulsion according to the present invention contains the hybrid silver chlorobromide-silver iodide crystal (grain) of the present invention as a single silver halide crystal (grain). This hybrid crystal can be monodispersed or polydispersed. Here, "monodisperse" has the same meaning as that defined in Illingsworth, published March 17, 1970, as described in Reference 1, and is a hybrid halogen. At least 95% by weight or number of silver oxide crystals
is within ±40% of the average grain size of the silver halide crystals. This average grain size is the average minimum grain size of the hybrid crystal. The relative advantages of "monodisperse" and "polydisperse" emulsions are well known in the art, such as that monodisperse emulsions exhibit higher contrast than polydisperse emulsions. The epitaxial silver chlorobromide crystals of the present invention, unless specifically modified during formation, render the hybrid crystals of the present invention reactive towards surface development. That is, the photographic emulsion according to the invention can be developed with a surface developer after imagewise exposure. The surface developer is capable of initiating development of a latent image on the surface of a silver halide crystal and is substantially free of soluble iodide salt or silver halide solvent. The hybrid crystal of the present invention can be structurally formed so that the latent image generated upon exposure exists within the crystal structure rather than on its surface. That is, the epitaxial silver chlorobromide (or silver bromide) crystal of the hybrid crystal of the present invention can be formed to be a crystal that primarily forms an internal latent image. To facilitate the formation of internal latent images in this hybrid crystal, internal dopants can be introduced into the epitaxy silver chlorobromide (or silver bromide) crystal. Examples of the internal dopant include silver, sulfur, iridium, gold, platinum, osmium, rhodium, tellurium, and selenium. Photographic emulsions according to the invention containing such mixed crystals are developed, for example, in internal developers containing silver halide solvents or soluble iodide salts. During the production of such hybrid crystals forming primarily internal latent images, epitaxial silver chlorobromide (or silver bromide) crystals are placed in the presence of, for example, non-silver metal ions, preferably polyvalent metal ions.
and epitaxy silver chlorobromide (or silver bromide)
Crystals are preferably formed in the presence of water-soluble salts of the individual metals, more preferably in acidic media. At this time, the preferably used polyvalent metal ions are:
Divalent metal ions (lead ions, etc.), trivalent metal ions (antimony, bismuth, arsenic, gold, iridium, rhodium ions, etc.), or tetravalent metal ions (iridium ions, etc.) are included. and,
Preferred polyvalent metal ions of the present invention are iridium,
Bismuth or lead. Epitaxial silver chlorobromide (or silver bromide) crystals generally contain 10 ⁻⁹ mol %, preferably 10 ⁻⁶ mol %, of internal dopants based on the epitaxial silver chlorobromide (or silver bromide); , about 10 ⁻¹ mole per mole of epitaxial silver chlorobromide (or silver bromide) in the epitaxial silver chlorobromide (or silver bromide) crystal, preferably
Present in concentrations less than 10 ^-4 molar. The photographic emulsion according to the present invention has a discontinuous layer of the above-mentioned mixed crystal and a continuous layer of a binder. The hybrid crystal used in the present invention is obtained by forming an epitaxial silver chlorobromide crystal on a polyhedral crystal plane of silver iodide as a crystal substrate by a method including the simultaneous mixing method of [A] or [B] described above. There is. Silver iodide as a crystal substrate to be used can be prepared according to the methods described in References 1 and 2, and a specific production example thereof is also shown in Example 1 below. On the other hand, the hybrid crystal having epitaxial silver chlorobromide used is epitaxially joined without using the conversion method shown in Document 2. That is,
In the case of method [A], a salt/bromide ion-containing condensing raw material and an ion-containing feedstock are added to a reaction vessel containing a silver iodide emulsion by a simultaneous mixing method. The salt-bromide ion-containing feedstock and the silver ion-containing feedstock are of the conventional type used in co-mix silver chlorobromide production. On the other hand, when using the method [B] above, the simultaneous mixing method as shown in Example 1 of Document 1 (see Example 2 of the present invention) or the method shown in Example 9 of the same document or Example 1 of Document 2 is used. By the positive mixing method etc.
A silver chloride crystal is epitaxially bonded to a silver iodide polyhedral crystal as a crystal substrate, and then (a) of the above [B]
Silver bromide crystals may be epitaxially bonded to silver chloride crystals by the simultaneous mixing method shown in (b) above, or silver chlorobromide crystals may be epitaxially bonded to silver chloride crystals by the simultaneous mixing method shown in (b) of [B] above. The bromide ion-containing feedstock or the salt/bromide ion-containing feedstock and the silver ion-containing feedstock used in the simultaneous mixing method of (a) or (b) in [B] described above are silver bromide or salt odor This is the usual type used in silver oxide production. In the case of method [B], in both cases (a) and (b), the silver chloride crystals of the epitaxial silver chlorobromide account for the entire epitaxial silver chlorobromide.
It is desirable that the content be limited to 75 mol% or less, more preferably 60 mol% or less. The photographic binder is present, at least in part, in the reaction vessel dispersing the silver iodide crystals, and a further binder is present in the reaction vessel in which the silver iodide crystals are dispersed; Added. If the internal dopants described above are required, they are added to any of the above feedstocks or into the reaction vessel. The final proportion of epitaxial silver chlorobromide in the photographic emulsion according to the invention is then determined by limiting the amount of silver and/or salt-bromide ions introduced. The silver halide photographic emulsions according to the present invention can be adjusted by blending different emulsions to obtain desired photographic properties. This method allows control over photographic speed and contrast. Photographic emulsions according to the invention are those in which at least 50 weight percent of the total silver halide crystals are hybrid crystals according to the invention, when the hybrid crystals according to the invention are present together with other silver halide crystals in which they are blended. , the hybrid crystal of the present invention is primarily involved in image formation. In the present invention, silver chloride crystals and the hybrid crystal of the present invention can be blended. The advantage of blends of silver chloride crystals is that, even though these crystals are not directly or chemically developed under the conditions set in the exposure or development process, development speed and/or silver image density is dependent on the physical properties of the silver chloride crystals. is substantially strengthened for target development. The blending ratio of this silver chloride crystal and the hybrid silver chlorobromide-silver iodide crystal of the present invention can be arbitrarily selected depending on the application. In order to obtain a remarkable effect by solution physical development, 1 to 50 mol % of the total silver halide, more preferably 5 to 50 mol %, should be silver chloride crystals blended with the hybrid crystals of the present invention. desirable. A hydrophilic colloid is used as a binder in the photographic emulsion according to the present invention. Specific examples include natural substances such as gelatin, derivative gelatin, and polysaccharides, and synthetic polymers such as water-soluble polyvinyl compounds. Specific examples of synthetic polymers preferably used in the present invention are listed in Documents 1 and 2. The photographic emulsion according to the present invention is coated on a suitable support to provide a silver halide photographic light-sensitive material. Its specific configuration is detailed in Documents 1 and 2. Further, the photographic emulsion according to the present invention or a photographic light-sensitive material using the same may contain various photographic additives according to the methods described in Documents 1 and 2. For example, development regulators, antifoggants, stabilizers, developing agents, hardeners, antistatic agents, plasticizers, lubricants, bleaching agents, ultraviolet absorbers, antihalation dyes, filter dyes, etc. are added as necessary. can do. The photographic emulsion according to the present invention can be effectively applied to various silver halide photographic materials such as those for X-ray, color, monochrome, transfer, and high contrast. The silver halide photographic emulsion according to the present invention can be chemically sensitized according to a conventional method. Preferred examples of chemical sensitizers and sensitization methods that can be used are given in Reference 1.
and 2. Further, examples of development processing of photographic light-sensitive materials using the photographic emulsion according to the present invention are shown in Documents 1 and 2. That is,
In the present invention, physical development can also be carried out using conventional techniques, and conventional transfer methods (colloid transfer method, silver salt diffusion transfer method, invisibility transfer method, color transfer method, etc.)
It can be used for etc. In order to develop epitaxial silver chlorobromide crystals or both epitaxial silver chlorobromide crystals and silver iodide crystals as crystal substrates in the mixed crystals in the photographic emulsion according to the present invention, a developing agent must be selected and development conditions must be adjusted. Just control it. Strong developing agents such as hydroquinone, catechol, and phenidone can be used to obtain complete development of mixed silver halide crystals, and similarly color developing agents such as aminophenol and p-phenylenediamine can be used with dye-forming couplers. When used together, virtually complete development of mixed silver halide crystals is obtained. On the other hand, when this color developing agent is used for development in the absence of dye-forming couplers, only the epitaxial silver chlorobromide crystals are selectively developed. This is because development begins with silver chlorobromide. At relatively slow development rates and without agitation, development ends after development of the epitaxial crystals is substantially completed but before development of most of the crystal substrate silver iodide has begun. The amount of iodide ions released during development can also be controlled. The photographic emulsion according to the invention is suitable for use in redox amplification systems which require a heterogeneous catalyst to enable the reaction of an oxidizing agent and a reducing agent. The oxidizing agent and reducing agent that can be used at this time and their specific methods are detailed in Documents 1 and 2. Furthermore, as described in the same document, the photographic emulsion according to the present invention can also be applied to thermosensitive photographic materials. Further, silver halide photographic light-sensitive materials using the photographic emulsion according to the present invention are disclosed in, for example, Japanese Patent Application Laid-Open No. 52-20025
No. 52-30430, Patent Application No. 53-33326, No. 53-
One-bath development, bleach-fixing and color image reinforcement treatments described in No. 45150, No. 53-70055, No. 53-70056, etc. can be applied. The present invention will be illustrated below with reference to Examples, but the embodiments of the present invention are not limited thereto. Example 1 Monodispersed silver iodide emulsions were prepared using three types of solutions shown in Table 1.

[Table] A commercially available iodine ion electrode and a double junction type silver/silver chloride comparison electrode (junction solution, 1 mol KNO ₃ aqueous solution) were immersed in solution A, the potential was measured, and this potential (-175 mV) was applied to solution B, The flow rate of solution B was adjusted and controlled to remain constant during the addition of solution C. Solution C was added at a constant rate of 0.5 ml/min for 6 minutes from the start of addition, and thereafter.
It was increased linearly at a rate of 0.385 ml/min over 10 minutes, and it took 197 minutes to add all of Solution C.
Addition was stopped when all of the solution C was added, and water washing and desalting were performed by the following operations. As a precipitant, a 5% aqueous solution of Demol N manufactured by Kao Atlas Co., Ltd. and a 20% aqueous solution of magnesium sulfate were added at a ratio of 10:9 until precipitation occurred. After the precipitate settles by standing still,
The supernatant was decanted and 3000 ml of distilled water was added to redisperse the precipitate. A 20% aqueous magnesium sulfate solution was added again until precipitation occurred. After settling the precipitate, the supernatant was decanted, an aqueous solution of ossein gelatin (containing 56.6 g of gelatin) was added, and the mixture was incubated at 35°C for 20
Disperse by stirring for a minute and bring the total volume to 2270ml with distilled water.
Adjusted to. Hereinafter, this emulsion will be referred to as EM-1. Electron micrographs show that this EM-1 emulsion has an average grain size of 0.25 μm and a standard deviation of 20 μm of the average grain size.
%. Furthermore, X-ray diffraction revealed that this EM-1 emulsion contains β- and almost no α or γ.
It was found that it consists of silver phase iodide. Example 2 Emulsions in which pure silver chloride was epitaxially bonded to silver iodide were prepared using three types of solutions shown in Table 2.

[Table] Add 70.6 ml of solution D and 70.6 ml of solution E to solution F at 35°C.
They were added simultaneously using the double jet method over a period of time. After the addition was completed, washing with water and desalting were carried out by the following operations. A 5% aqueous solution of Demol N manufactured by Kao Atlas Co., Ltd. and a 20% aqueous solution of magnesium sulfate were used as precipitants.
The mixture was added at a ratio of 10:9 until a precipitate formed. After allowing the precipitate to settle and decanting the supernatant,
800 ml of distilled water was added and dispersed again. 20% magnesium sulfate was added again until precipitation occurred. After the precipitate has settled, the supernatant liquid is decanted and an aqueous solution of ossein gelatin (containing 10 g of gelatin) is added.
The mixture was dispersed by stirring at 35° C. for 20 minutes, and the total volume was adjusted to 200 ml with distilled water. This emulsion is hereinafter referred to as EM-2. Example 3 Before the desalting step, 35 ml of a 1M KBr aqueous solution was added to an emulsion prepared in the same manner as in Example 2, and the emulsion was heated at 50°C.
After heating for 10 minutes to convert bromine into the epitaxially bonded silver chloride, water washing and desalination were performed in the same manner as in Example 2. This emulsion is shown below.
It is called EM-3. Example 4 Using the three types of solutions shown in Table 3, emulsions were prepared in which silver iodide and silver chlorobromide were epitaxially bonded by the method [A] of the present invention without conversion. .

[Table] 70.6 ml of solution D and 70.6 ml of solution G were simultaneously added to solution F at 35°C over a period of 6 minutes using the double jet method. After the addition was completed, washing with water and desalting were carried out in the same manner as in Example 2. This emulsion is hereinafter referred to as EM-4. Example 5 Using the three types of solutions shown in Table 4, a small amount of silver chloride was epitaxially bonded to silver iodide, and then silver bromide was epitaxially bonded to this silver chloride to prepare an emulsion. That is, an emulsion was prepared by the method (a) of [B] of the present invention.

[Developer composition]

Metol 3g Anhydrous sodium sulfite 50g Hydroquinone 6g Sodium carbonate 29.5g Potassium bromide 1.0g Add water and adjust to 1. Sensitometric results are shown in Table 5.

[Treatment process and conditions]

Time Temperature (1) Color development 3.5 minutes 33℃ (2) Bleach-fixing 2.0 minutes 33±2℃ (3) Washing with water 3.0 minutes 33±2℃ (4) Drying [Color development processing solution composition] N-ethyl -N-β-Methanesulfonamidoethyl-3-methyl-4-aminoaniline sulfate 4.5g Hydroxyamine 2.0g Potassium carbonate 25.0g Sodium bromide 0.3g Anhydrous sodium sulfite 2.0g Benzyl alcohol 14.5ml Add water to 1 and adjust the pH with potassium hydroxide.
Adjust to 10.20. [Bleach-fix solution composition] Ethylenediaminetetraacetic acid iron sodium salt
56g Ammonium thiosulfate 100g Sodium bisulfite 10g Ethylenediaminetetraacetic acid 18g Add water to make 1, and adjust the pH to 7.0 with aqueous ammonia. The density of magenta pressure fog generated on the bent portion of the sample after treatment was measured. The results are shown in Table 6.

[Treatment process and conditions]

Time Temperature (1) One-bath color developing bleach-fixing bath 3.5 minutes 33℃ (2) Washing with water 3 minutes (3) Drying [Composition of one-bath color developing bleach-fixing bath] N-ethyl-N-β-methane Sulfonamidoethyl-3-methyl-4-aminoaniline sulfate 5.6g Potassium carbonate 30.0g Sodium bromide 0.10g Anhydrous sodium sulfite 4.50g Benzyl alcohol 10.0ml Sodium thiosulfate 25.0g Sodium ethylenediaminetetraacetate 30.0g Add water 1 and adjust the pH with sodium hydroxide.
Adjust to 10.60. The results are shown in Table 7.

[Composition of one-bath color development bleach-fixing treatment bath]

Sodium sulfite 20g Sodium carbonate 30.0g Sodium thiosulfate 20.0g [Co(NH ₃ ) ₆ ] (CH ₃ COO) ₃ 20.0g N-ethyl-N-β-methanesulfonamidoethyl-3-methyl-4-aminoaniline Sulfate 10.0g Hydrogen peroxide (30%) 3ml Finished with water and adjusted to PH12.5. Example 10 The following solution J was used in place of solution I in Example 5. Solution J: 0.5 molar aqueous solution of KBr 0.5 molar aqueous solution of KCl In the same manner as in Example 5 except that a small amount of silver chloride was added to silver iodide. An emulsion was prepared by epitaxially bonding the silver chloride with silver chlorobromide. That is, an emulsion was prepared by the method (b) of [B] of the present invention. When the experiments shown in Examples 6 to 8 described above were conducted on the obtained emulsion according to the present invention, good results comparable to those of the EM-4 emulsion were obtained.

Claims (1)

[Scope of Claims] 1. A hybrid halide comprising a polyhedral crystal of silver iodide and a crystal of silver chlorobromide formed by epitaxially joining the polyhedral crystal by the method shown in [A] or [B] below. having silver crystals, at least half of the polyhedral crystal faces of the silver iodide are substantially free of epitaxial silver chlorobromide, and the silver chlorobromide accounts for 75 mol% or less of the total mixed silver halide; A silver halide photographic emulsion characterized by: [A] A method of epitaxially bonding a silver chlorobromide crystal to a polyhedral silver iodide crystal by simultaneously mixing a solution containing water-soluble chloride and water-soluble bromide with a silver salt solution. [B] A silver chloride crystal is epitaxially bonded to a polyhedral crystal of silver iodide, and the silver chloride crystal is bonded to (a). Simultaneous mixing of a solution containing water-soluble bromide and a silver salt solution, or (b). A method of epitaxially bonding silver bromide or silver chlorobromide crystals by simultaneously mixing a solution containing water-soluble chloride and water-soluble bromide with a silver salt solution. 2. The silver halide photographic emulsion according to claim 1, wherein the silver iodide is mainly beta-phase silver iodide of truncated double pyramid crystal type. 3. A silver halide photographic emulsion according to claim 1, wherein said silver iodide has a minimum average grain size of at least 0.2 microns. 4 95% of the weight or number of mixed silver halide crystals
The silver halide photographic emulsion according to claim 1, wherein the silver halide emulsion has a mean grain size within ±40% of its average grain size. 5. The silver halide photographic emulsion according to claim 1, wherein 1 to 50 mol % of the total mixed silver halide is silver chlorobromide. 6. The silver halide photographic emulsion according to claim 1, wherein the silver chlorobromide crystals are crystals that mainly form an internal latent image. 7. The silver halide photographic emulsion according to claim 1, wherein the silver chlorobromide crystals contain an internal dopant that facilitates the formation of an internal latent image upon exposure. 8. The method according to claim 1, wherein 1 to 50 mol % of the total silver halide is present in the form of other silver halide crystals blended with mixed silver halide crystals. Silver halide photographic emulsion. 9. A silver halide photograph according to claim 8, characterized in that at least 5 mol % of the total silver halide is present in the form of another silver chloride blended with crystals of mixed silver halide. emulsion. 10. The silver halide photographic emulsion according to claim 8 or 9, characterized in that the silver halide photographic emulsion contains a dye-forming coupler. 11. The silver halide photographic emulsion according to claim 7, wherein the internal dopant is iridium. 12. The silver halide according to claim 1, wherein the silver chloride crystals account for 75 mol% or less of the total epitaxial silver chlorobromide crystals epitaxially bonded to the polyhedral iodide crystals. Photographic emulsion.