JPH08114879A - Silver halide emulsion for photography and silver halide photographic sensitive material - Google Patents

Abstract

PURPOSE: To obtain a photographic photosensitive material having high sensitivity and excellent preservability for latent images by incorporating such a photographic silver halide emulsion that is prepared by changing pH in the system in the period from the initiation to the completion of the one selected from spectral sensitization and chemical sensitization. CONSTITUTION: This silver halide photographic sensitive material contains a silver halide such an emulsion that is produced by changing pH in the system in the period from the initiation to the completion of at least one of spectral sensitization and chemical sensitization. The initiation of at least one of spectral sensitization and chemical sensitization means such a point of time that an additive relating to sensitization is first added after particles are formed and pH, pAg, temp. or the like are controlled to desired values. The completion of sensitization means such a point of time that a stabilizer is added after the spectral or chemical sensitization is effected for the optimum time. The additive relating to sensitization is an additive to be added to an emulsion in the sensitizing process such as a sulfur sensitizer and selenium sensitizer. As for the pH controlling agent, potassium hydroxide, sodium hydroxide or the like can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photographic silver halide emulsion and a method for producing the same, and more specifically, it has high sensitivity and excellent latent image storability, and is particularly suitable for use in a general silver halide photographic light-sensitive material. It relates to a silver halide emulsion for photography.

[0002]

2. Description of the Related Art In recent years, the sensitivity of popular type light-sensitive materials has been remarkably increased, and photography has become easier and more convenient. Especially in recent years, with the widespread use of photography equipment called compact cameras and lens-equipped films, photography in various scenes has been made, and the demand for higher sensitivity of light-sensitive materials has never tired of it. It is an eternal theme for.

Further, due to the daily use of photography, the time (month / day) from photography to development often passes for a long time (period). If a long time elapses between shooting and development, the latent image generated by exposure will regress over time, so-called "latent image regression" becomes a major problem, so it is also excellent in latent image storability. This is one of the essential conditions for a photographic light-sensitive material.

[0004] As a study for increasing the sensitivity, various techniques for forming a photographic light-sensitive material have been studied, and in terms of silver halide grains, adjustment of grain shape and composition, introduction of transition line, etc. can be mentioned. Regarding sensitization and spectral sensitization,
Studies on new sensitizers (for example, selenium, tellurium, etc.), control of silver sulfide nucleus formation by combination with other additives, control of dye adsorption, etc.
The current situation is that each has advantages and disadvantages.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a silver halide photographic light-sensitive material having high sensitivity and excellent latent image storability.

[0006]

The above object of the present invention is for photographic use, which is formed by changing the pH of the system from the start to the end of at least one selected from spectral sensitization and chemical sensitization. It is achieved by a silver halide emulsion and a silver halide photographic light-sensitive material containing the silver halide emulsion.

In particular, the process of increasing the pH after the chalcogen sensitizer is added, and the pH when the spectral sensitizing dye is added is higher than the pH when the chalcogen sensitizer is added. I also found that Regarding the change range of pH, the effect is obtained when the difference between the maximum value and the minimum value of pH is 1.0 or more from the start of at least one selected from spectral sensitization and chemical sensitization to the end of both. I found it big.

The details of the present invention will be described below.

In the present invention, the initiation of at least one selected from spectral sensitization and chemical sensitization means that pH and pA are determined after grain formation (when desalting is carried out, desalting is terminated if necessary).
After adjusting g, temperature, etc. to an arbitrary value, it means the time of adding the additive for sensitization for the first time, and the end of the sensitization means
It means the time when the stabilizer is added after optimum time spectroscopy or chemical sensitization.

The additives relating to sensitization include various sensitizers such as sulfur sensitizers, selenium sensitizers, tellurium sensitizers, spectral sensitizing dyes, supersensitizers, and silver halide solvents. It is an additive added to the emulsion during sensitization.

As the pH adjusting agent for changing the pH, general acids or bases such as potassium hydroxide, sodium hydroxide, acetic acid and citric acid can be used.

The halide composition of the silver halide emulsion is preferably silver iodobromide or silver bromide.

The silver halide grains contained in the silver halide emulsion are preferably those having a regular crystal form such as a cube, octahedron or tetradecahedron, or tabular grains. Twinned silver halide grains having crystal faces are preferred. A twin is a silver halide crystal having one or more twin planes in one grain. The twin morphology is classified by Photographishe Korrespondenz by Klein and Moiser. ] 99
Volume, page 99, volume 100, page 57.

When tabular silver halide grains are used, the average value of the ratio of grain size to thickness of tabular grains (also referred to as aspect ratio) is preferably 12 or less, more preferably less than 5 (particularly 4). Less than), and 1.1 or more,
Especially 1.2 or more is preferable.

The average grain size r of the silver halide grains is
It is preferably 0.1 μm or more (particularly 0.2 μm or more [further 0.3 μm or more]), and 5.0 μm or less (particularly 4.0 μm or less [further 3.0 μm or less]). The average particle size r is the product of the frequency ni and ri ^{3 of} particles having the particle size ri, ni × r
It is defined as the average volume diameter based on i ³ .

The term "grain size" as used herein means a diameter of a projected image of a silver halide grain converted into a circular image having the same area. The particle size can be obtained, for example, by magnifying the particles with an electron microscope at a magnification of 10,000 to 70,000 and measuring the particle diameter on the print or the area at the time of projection (the number of measured particles is not measured). Discrimination shall be 1,000 or more).

The silver halide emulsion is preferably a monodisperse emulsion. Here, the monodisperse emulsion is defined as the breadth of the grain size distribution (%) = (standard deviation / average grain size) × 100. 20% or less. Further, in the present invention, it is preferable that the width of the distribution is 15% or less. Here, the average particle size and the standard deviation are obtained from the particle size ri defined above and the frequency ni of the particles having the particle size ri.

The average silver iodide content in the entire silver halide grains is 1 mol% or more (particularly 2 mol% or more [and 3
Mol% or more]) is preferable, and 15 mol% or less (particularly 12 mol% or less [further 10 mol% or less]) is preferable.

The silver halide composition structure of the silver halide grains preferably has a continuously changing silver halide composition or a core / shell structure in order to efficiently achieve sensitization.

In this case, it is preferable to have a high silver iodide-containing phase having a silver iodide content of 8 mol% or more (particularly 10 mol% or more [more than 20 mol%]) inside the grain. However, the content is good enough not to precipitate the silver iodide phase, and is preferably 45 mol% or less (particularly 40 mol% or less). Further, the outermost phase of the silver halide grain having a high silver iodide content phase inside the grain is preferably formed of a low silver iodide content phase having a lower silver iodide content than the high silver iodide content phase. The silver iodide content of the low silver iodide-containing phase forming the outermost phase is preferably 10 mol% or less (particularly 6 mol% or less (further 4 mol% or less)).

An intermediate phase having a different silver iodide content may be present between the outermost phase and the high silver iodide containing phase. The silver iodide content of the intermediate phase is preferably 10 mol% or more (particularly 12 mol% or more), and 22 mol% or less (particularly 20 mol% or less). The silver iodide contents of the outermost phase and the intermediate phase, and the silver iodide contents of the intermediate phase and the high silver iodide containing phase are preferably 6 mol% or more, particularly preferably 10 mol% or more. Good.

In the above embodiment, another silver halide is added at the center of the internal high silver iodide containing phase, between the internal high silver iodide containing phase and the intermediate phase, or between the intermediate phase and the outermost phase. There may be phases.

The volume of the outermost phase is preferably 4% or more (particularly 10% or more) of the whole particles, and 70% or less (particularly 50% or less). The volume of the high silver iodide-containing phase is preferably 10% or more (especially 20% or more) of the whole grain, and 80% or less (especially 50% or less). The volume of the intermediate phase is preferably 5% or more (particularly 20% or more) of the whole particles, and 60% or less (particularly 55% or less).

These phases are a single phase having a substantially uniform composition, a phase group consisting of a plurality of phases having a uniform composition and having a stepwise change in composition, or a continuous phase in which the composition continuously changes in an arbitrary phase. It may be either a phase or a combination thereof.

The silver halide grains contained in the silver halide emulsion of the present invention are prepared by preliminarily allowing an aqueous solution containing a protective colloid and seed particles to be present in a reaction vessel, and if necessary, silver ions, halogen ions or silver halide fine particles. It is obtained by supplying and crystallizing seed particles. Here, the seed particles can be prepared by a single jet method or a controlled double jet method well known in the art. The halogen composition of the seed grains is arbitrary, silver bromide,
It may be any of silver iodide, silver chloride, silver iodobromide, silver chlorobromide, silver chloroiodobromide, and silver chloroiodobromide, with silver bromide and silver iodobromide being preferred.

When seed particles are used in the present invention, the seed particles may have a regular crystal form such as a cube, an octahedron or a tetrahedron, or an irregular shape such as a sphere or a plate. It may have a crystalline form. In these particles,
Any ratio can be used for the {100} plane and the {111} plane. Further, particles having a composite form of these crystal forms may be used, and particles of various crystal forms may be mixed, but it is preferable to use spherical seed particles having two opposing parallel twin planes.

As the means for forming the silver halide emulsion of the present invention, various methods well known in the art can be used. That is, the single jet method, the double jet method
The jet method, the triple jet method and the like can be used in any combination. Further, a method of controlling pH and pAg in the liquid phase in which silver halide grains are produced according to the growth rate and stage of silver halide grains can also be used. The silver halide emulsion of the present invention can be produced by any of the acidic method, the neutral method and the ammonia method.

In the production of the silver halide emulsion of the present invention, halide ions and silver ions may be mixed at the same time, or one of them may be present while the other is mixed. Further, while considering the critical growth rate of silver halide crystals, halide ions and silver ions may be sequentially or simultaneously added to the mixing vessel while controlling pAg and pH to grow. The conversion method may be used to change the silver halide composition of the grains at any step of the silver halide formation. Further, halide ions and silver ions may be supplied as fine silver halide particles into the mixing vessel.

In the production of the silver halide emulsion of the present invention, a known silver halide solvent such as ammonia, thioether or thiourea can be present.

In the silver halide emulsion of the present invention, unnecessary soluble salts may be removed at the end of the growth of silver halide grains, or may remain contained. When removing the salts, Research Disclosure (Resear
ch Disclosure (hereinafter abbreviated as RD)) No. 17643, Item II.

The silver halide grains according to the present invention preferably have reduction sensitization inside the grains. The inside of the particle referred to here is a portion closer to the center than the inner 90% of the volume of the whole particle, and preferably a portion closer to the center than the inner 70%.

The reduction sensitization is carried out by adding a reducing agent to a silver halide emulsion or a mixed solution for grain growth, or adding this solution.
The ripening or grain growth of the emulsion is carried out under a low pAg condition of pAg = 7 or less or a high pH condition of pH = 7 or more.

A silver salt can be added to obtain a low pAg condition, and a water-soluble silver salt is preferable. Silver nitrate is preferred as the water-soluble silver salt. The pAg during aging is suitably 7 or less, preferably 6 or less, more preferably 1 to 3.
Incidentally, pAg = -log [Ag ⁺ ]. Reduction sensitization under high pH conditions is carried out by adding an alkaline compound to a silver halide emulsion or a mixed solution for grain growth. As the alkaline compound, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonia and the like can be used. When ammoniacal silver nitrate is used for silver halide formation, an alkaline compound excluding ammonia is preferably used.

As a method for adding the silver salt or the alkaline compound for reduction sensitization, rush addition may be carried out or addition may be carried out over a certain period of time. When it takes a certain time,
It may be added at a constant flow rate, or may be added by changing the flow rate like a function. Also, the required amount may be added in several divided portions. Prior to the addition of the soluble silver salt and / or the soluble halide into the reaction vessel, it may be allowed to exist in the reaction vessel or mixed in the solution of the soluble halide,
You may add with a halide. Furthermore, the addition may be performed separately from the soluble silver salt and the soluble halide.

In the preparation of the silver halide emulsion of the present invention, the method of growing from seed grains is preferably used.
Specifically, it is obtained by preliminarily allowing an aqueous solution containing a protective colloid and seed particles to exist in a reaction vessel, and optionally supplying silver ions, halogen ions or silver halide particles to grow the seed particles. . The seed particles can be prepared by a single jet method, a controlled double jet method, etc. well known in the art. The halogen composition of the seed grains is arbitrary and may be any of silver bromide, silver iodide, silver chloride, silver iodobromide, silver chloroiodide, silver chlorobromide and silver chloroiodobromide. Silver bromide and silver iodobromide are preferable,
In the case of silver iodobromide, the average silver iodide content is preferably 1 to 20 mol%.

In the case of growing from seed grains, in low pAg ripening, it is preferable to add silver nitrate for ripening after the formation of the seed emulsion, that is, immediately before desalting of the seed grains to after desalting. In particular, it is preferable to add silver nitrate after the desalting of the seed particles for ripening, and the ripening temperature is preferably 40 ° C. or higher and 50 ° C. to 80 ° C. Aging time is 30 minutes or more, preferably 50 to 150 minutes.

In the case of growing from seed grains, in high pH ripening, the grain should be grown at least once in an environment of pH 7 or more until a portion corresponding to 70% of the volume of the grown grain grows. Is preferable, and the pH value is 50% by the time the part corresponding to 50% of the volume of the grown particles grows.
It is more preferable to grow the particles through an environment of 7 or more, and it is preferable to grow the particles through an environment of pH 8 or more at least once until a portion corresponding to 40% of the volume of the grown particles grows. Most preferred.

An oxidizing agent is preferably used in the emulsion comprising reduction-sensitized silver halide grains used in the present invention. Specifically, H ₂ O ₂ , NaBO ₂ , H ₂ O ₂ 3H ₂ O ₂ , Na
₄ P ₂ O ₇ −2H ₂ O ₂ , 2Na ₂ SO ₄ −H ₂ O ₂ −2H ₂ O, hydrogen peroxide (water) and its adducts, K ₂ S ₂ O ₃ , K ₂ C ₂ O ₃ , K ₄ P ₂ O ₃ , K ₂ [T
i (O ₂ ) C ₂ O ₄ ] −3H ₂ O and other peroxy acids, peracetic acid, ozone,
Examples thereof include iodine, bromine and thiosulfonic acid compounds. The time of addition may be anywhere in the silver halide emulsion manufacturing process. It can also be added prior to the addition of the reducing agent. Further, after adding the oxidizing agent, it is also possible to newly add a reducing substance to neutralize the excess oxidizing agent.
These reducing substances are substances capable of reducing the above-mentioned oxidizing agent, and include sulfinic acids, di- and trihydroxybenzenes, chromanes, hydrazines and hydrazides,
Examples include p-phenylenediamines, aldehydes, aminophenols, enediols, oximes, reducing sugars, phenidones, sulfites, and ascorbic acid derivatives.

In the present invention, a sulfur sensitizer, a selenium sensitizer, a tellurium sensitizer and the like can be used as the chemical sensitizer.

Sulfur sensitizers applicable in the present invention include 1,3-diphenylthiourea, triethylthiourea,
Preferred examples include thiourea derivatives such as 1-ethyl-3- (2-thiazolyl) thiourea, rhodanine derivatives, dithicarbamic acids, polysulfide organic compounds, sodium thiosulfate, and simple sulfur. As the simple substance of sulfur, α-sulfur belonging to the orthorhombic system is preferable.

Other sulfur sensitizers include US Pat.
574,944, 2,410,689, 2,278,947, 2,728,6
68, 3,501,313, 3,656,955, etc., West German Application Publication (OLS) 1,422,869, JP-A-56-24937
The sulfur sensitizers described in JP-A No. 55-45016 and the like can also be used.

The selenium sensitizers that can be used in the present invention include a wide variety of selenium compounds. For example, in this regard, U.S. Pat.Nos. 1,574,944, 1,602,592, 1,623,
499, JP 60-150046, JP 4-25832, 4-109
No. 240 and No. 4-147250. Useful selenium sensitizers include colloidal selenium metal, isoselenocyanates (eg, allyl isoselenocyanate, etc.),
Selenoureas (eg, N, N-dimethylselenourea, N, N,
N'-triethylselenourea, N, N, N'-trimethyl-N'-
Heptafluoroselenourea, N, N, N′-trimethyl-N′-
Heptafluoropropylcarbonyl selenourea, N, N,
N′-trimethyl-N′-4-nitrophenylcarbonyl selenoureas, etc.), selenoketones (eg, selenoacetone, selenoacetophenone, etc.), selenoamides (eg, selenoacetamide, N, N-dimethylselenobenzamide, etc.), selenocarbons Acids and selenoesters (eg 2-selenopropionic acid, methyl-3-selenobutyrate, etc.), selenophosphates (eg tri-p-
Triselenophosphate, etc.), selenides (dimethyl selenide, triphenylphosphine selenide, etc.)
Is mentioned. Particularly preferred selenium sensitizers are selenoureas, selenoamides, and selenides.

Specific examples of techniques for using these selenium sensitizers are disclosed in the following patent specifications. U.S. Patent No. 1,57
4,944, 1,602,592, 1,623,499, 3,297,4
66, 3,297,447, 3,320,069, 3,408,196
No. 3,408,197, 3,442,653, 3,420,670,
No. 3,591,385, French Patent No. 2,693,038, No. 2,093,
No. 209, Japanese Patent Publication No. 52-34491, No. 52-34492, No. 53-295
No. 57-22090, JP-A-59-180536, and 59-185330.
No. 59-181337, 59-187338, 59-192241,
No. 60-150046, No. 60-151637, No. 61-246738, JP-A No. 3-4221, No. 3-24537, No. 3-111838, No. 3-116132.
No. 3, No. 3-148648, No. 3-237450, No. 4-16838, No. 4-2
5832, 4-32831, 4-96059, 4-109240, and
4-140738, 4-140739, 4-147250, 4-149437
No. 4, No. 4-184331, No. 4-190225, No. 4-191729, No. 4-
195035, British Patents 255,846, 861,984, HE
Spencer et al., Journal of Photographic Science, 31
, 158-169 (1983) and other research papers.

Tellurium sensitizers and sensitizing methods usable in the present invention are described in US Pat. Nos. 1,623,499 and 3,32.
0,069, 3,772,031, 3,531,289, 3,655,394
No., British Patent Nos. 235,211, 1,121,469, 1,295,46
No. 2, No. 1,396,696, Canadian Patent No. 800,958, Japanese Patent Laid-Open No. 4
-20464, etc. Examples of useful tellurium sensitizers include telluroureas, telluroamides and the like.

The amount of the sulfur sensitizer, selenium sensitizer, and tellurium sensitizer added is not uniform depending on the type of silver halide emulsion, the type of compound used, the ripening conditions, etc. It is preferably 1 × 10 ⁻⁴ mol to 1 × 10 ⁻⁹ mol per mol. More preferably 1 × 10 ⁻⁵ mol to 1 ×
It is 10 ^-8 mol.

In the chemical sensitization of the present invention, the sensitivity can be further increased by using gold sensitization together. Examples of useful gold sensitizers include chloroauric acid, gold thiosulfate, gold thiocyanate, and the like, U.S. Patent Nos. 2,597,856, 5,049,484, and 5,
049,485, JP-B-44-15748, JP-A-1-147537, 4
Examples include gold complexes of organic compounds disclosed in No. 70650 and the like.

The above-mentioned various sensitizers may be added by dissolving them in water or an organic solvent such as methanol or ethanol alone or in a mixed solvent depending on the properties of the compound used, or by adding gelatin. A method of mixing with a solution in advance and adding it may be a method disclosed in JP-A-4-140739, that is, a method of adding in the form of an emulsion dispersion of a mixed solution with a polymer soluble in an organic solvent.

In the present invention, when the chemical sensitization is carried out in the presence of the silver halide adsorbing compound, the effect of the present invention is further enhanced. The silver halide-adsorptive compound is a sensitizing dye,
Antifoggants and stabilizers can be used.

The silver halide emulsion of the present invention can be optically sensitized to a desired wavelength region by using a dye known as a sensitizing dye in the photographic industry. The sensitizing dyes may be used alone or in combination of two or more. Along with a sensitizing dye, a dye that does not itself have a spectral sensitizing effect or a compound that does not substantially absorb visible light,
A supersensitizer that enhances the sensitizing action of the sensitizing dye may be contained in the emulsion.

As the sensitizing dyes, polymethine dyes containing cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes, hemioxonol dyes, oxonols, merostyryl and streptocyanines are used. Can be mentioned.

Examples of the antifoggants and stabilizers include tetrazaindenes and azoles such as benzothiazolium salts, nitroindazoles, nitrobenzimidazoles, chlorobenzimidazoles, promobenzimidazoles and mercaptothiazoles. , Mercaptobenzimidazoles, aminotriazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles (particularly 1-phenyl-5-mercaptotetrazole), and mercaptopyrimidines, mercaptotriazines, such as thioketo such as oxazolithion. Compounds, further benzenethiosulfinic acid, benzenesulfinic acid, benzenesulfonic acid amide, hydroquinone derivatives, aminophenol derivatives, gallic acid derivatives, ascorbi Mention may be made of the acid derivatives.

In the present invention, good results are often obtained by performing sensitization in the presence of a silver halide solvent.

Examples of the silver halide solvent used in the present invention include US Pat. Nos. 3,271,157, 3,531,2891, and 3,5.
(A) Organic thioethyls described in JP-A-74,628, JP-A-54-1019 and JP-A-54-158917, and
53-82408, 55-77737, 55-2982 and the like (b) thiourea derivatives, and (c) an oxygen or sulfur atom described in JP-A-53-144319 Examples thereof include silver halide solvents having a thiocarbonyl group sandwiched between nitrogen atoms, (d) imidazoles described in JP-A-54-100717, (e) sulfite, (f) thiocyanate, and the like.

Specific examples of known photographic additives, various couplers and the like which can be used when a color photographic light-sensitive material is constituted by using the silver halide photographic emulsion of the present invention are described below.

[Item] [RD308119] [RD17643]] [RD18716] Color turbidity inhibitor page 1002 VII-I section 25 page 650 Dye image stabilizer 1001 page VII-J section 25 whitening agent 998 page V 24 page UV absorber page 1003 VIII-C, VIII-C page 25-26 light absorber page 1003 VIII page 25-26 light scattering agent page 1003 VIII filter dye page 1003 VIII page 25-26 binder 1003 page IX page 26 651 page 651 Antistatic agent 1006 pages XIII 27 pages 650 Hardeners 1004 pages X 26 pages 651 Plasticizers 1006 XII 27 pages 650 Lubricants 1006 XII 27 pages 650 Activators and coating aids 1005 pages XI 26 pages ~ Page 27 Page 650 Matting agent Page 1007 Page XVI Developer (included in the photosensitive material) Page 1011 Item XX-B Item Yellow coupler 1001 Item VII-D Item 25 Page VII-C to G Magenta coupler 1001 Page VII-D Item 25 VII-CG section Cyan coupler page 1001 VII-D section 25 page VII-C to G section Colored coupler 1002 section VII-G section 25 section VII-G DIR coupler 1001 section VII-F section 25 section VII-F section B R coupler page 1002 VII-F Other useful residues page 1001 VII-F release coupler alkali-soluble page 1001 VII-E coupler coupler dispersion method page 1007 section XIV support 1009 page XVII section 28 filter layer page 1002 Item VII-K Auxiliary layer page 1002 Item VII-K layer structure page 1002 Item VII-K Development method page 1010 XIX page 28-29 page 615

[0056]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 << Preparation of Emulsion Em-1 >> A seed emulsion (T-1) having two parallel twin planes was prepared by the following method with reference to the description of JP-A-5-34851. Was prepared.

Solution A Oscein gelatin 80.0 g Potassium bromide 47.4 g HO (CH ₂ CH ₂ O) _m [CH (CH ₃ ) CH ₂ O] _19.8 (CH ₂ CH ₂ O) _n H (m ± n = 9.77) 10% by weight methanol solution 0.48 g with water 8000 ml solution B silver nitrate 1200 g with water 1600 ml solution C ossein gelatin 32.2 g potassium bromide 790 g potassium iodide 70.34 g water 1600 ml solution D ammonia water 470 ml JP-A-62-160128 Using the stirrer described, solution B and solution C were added to solution A that was vigorously stirred at 40 ° C. for 7.7 minutes by the double jet method to generate nuclei. During this time, pBr was kept at 1.60.

Thereafter, the temperature was lowered to 20 ° C. over 35 minutes. Furthermore, the solution D was added in 1 minute, and the aging was continued for 5 minutes. The KBr concentration during aging was 0.03 mol / l, and the ammonia concentration was 0.66 mol / l.

After completion of aging, the pH was adjusted to 6.0 and desalting was carried out according to a conventional method. When the seed emulsion grains were observed with an electron microscope, the average grain size of the seed emulsion grains (T-1) was 0.
225 μm, the ratio of two parallel twin planes is 75% in the number ratio of all grains
Met.

Next, using the following seven kinds of solutions,
A tabular monodisperse comparative emulsion Em having parallel twin planes
-1 was prepared.

(Solution A) Ocein gelatin 69.0 g Distilled water 3268 ml HO (CH ₂ CH ₂ O) _m (CHCH ₃ CH ₂ O) _19.8 (CH ₂ CH ₂ O) _n H (m + n = 9.77) 10% by weight Methanol solution 2.50 ml Seed emulsion (T-1) 71.8 g Distilled water to 3500 ml.

(Solution B) 0.5N silver nitrate aqueous solution 959.0 ml (Solution C) potassium bromide 52.88 g ossein gelatin 35.55 g Distilled water is added to 959 ml.

(Solution D) 3.5N Silver Nitrate Aqueous Solution 4475.0 ml (Solution E) Potassium Bromide 1863.8 g Ocein Gelatin 179.0 g Finished to 4475 ml with distilled water (Solution F) 3% by weight of gelatin and silver iodide grains (average) Fine grain emulsion consisting of 0.05 μm grain size (preparation method is shown below) 2492.0 g * 6.06% by weight gelatin solution containing 0.06 mol potassium iodide 5000 ml, 7.06 mol silver nitrate and 7.06 mol potassium iodide 2000 ml of an aqueous solution containing each was added over 10 minutes. The temperature during fine particle formation was controlled at 40 ° C. After forming the particles, the pH was adjusted to 6.0 using an aqueous sodium carbonate solution. The finished weight was 12.53 kg.

(Solution G) 1.75N Potassium Bromide Aqueous Solution Necessary amount Solution A was added to a reaction vessel, and while vigorous stirring, solutions B to F were added by the simultaneous mixing method according to the combinations shown in Table 1. , Grow seed crystals, core /
A shell type silver halide emulsion was prepared. However, solution B,
10% at 114.95 minutes after the start of addition of C and F
The pH was adjusted to 7.2 with potassium hydroxide.

Here, (1) solution B, solution C and solution F
Addition rate of (2) solution D, solution E and solution F, and (3) addition rate of solution D and solution E, respectively, with respect to the time, so as to correspond to the critical growth rate of silver halide grains. It was changed in a function-like manner, and the addition rate was controlled so that small particles other than the growing seed crystal and polydispersion due to Ostwald ripening did not occur.

The temperature of the solution in the reaction vessel was controlled at 75 ° C. and the pAg was controlled at 8.8 over the entire area of crystal growth. pA
Solution G was added as needed for g control.

The amount of silver added and the silver iodide content of the silver halide phase forming the surface at that time with respect to the addition time of the reaction solution are also shown in Table 1.

After grain growth, desalting treatment was carried out according to the method described in Japanese Patent Application No. 4-59351, and then an aqueous gelatin solution was added and redispersed to adjust pH to 5.80 and pAg to 8.06 at 40 ° C.

The silver halide grains contained in the obtained silver halide emulsion were tabular silver halide grains having an average grain size of 1.42 μm (diameter in terms of projected area circle), an average aspect ratio of 2.0 and a grain size distribution of 14.0%. It was

[0071]

[Table 1]

<< Preparation of Emulsion Em-2 >> A monodisperse spherical seed emulsion (T-2) was prepared by the following method.

(Solution A-2) Ocein gelatin 80 g Potassium bromide 47.4 g Polyisopropylene-polyethyleneoxy-disuccinate sodium salt 10% methanol solution 20 ml Make up to 8000 ml with water.

(Solution B-2) 1200 g of silver nitrate 1600 ml with water.

(Solution C-2) Ocein gelatin 32.2 g Potassium bromide 840 g Water to 1600 ml.

(Solution D-2) Ammonia water 470 ml (Solution A-2) which was vigorously stirred at 40 ° C.
2) and (Solution C-2) were added by the double jet method for 11 minutes to generate nuclei. During this time, pBr was kept at 1.60. Then take 12 minutes to lower the temperature to 30 ° C and
Aged for minutes. Furthermore, (Solution D-2) was added over 1 minute, and then aging was performed for 5 minutes. The KBr concentration during aging was 0.07 mol / l, and the ammonia concentration was 0.63 mol / l.

After completion of the ripening, the pH was adjusted to 6.0 and desalting was carried out by a conventional method to obtain a spherical seed emulsion (T-2). When this seed emulsion was observed with an electron microscope,
It was a spherical emulsion having an average grain size of 0.318 μm and having twin planes.

Next, an emulsion Em-2 was prepared using the following seven kinds of solutions.

(Solution A-3) Ocein gelatin 268.2 g Distilled water 4000 ml Polyisopropylene-polyethyleneoxy-di-succinate sodium salt 10% methanol solution 1.5 ml Seed emulsion (T-2) 0.286 mol 28 wt% ammonia Aqueous solution 528.0 ml 56 wt% acetic acid aqueous solution 795.0 ml 0.005 Methanol solution containing 1 mol of iodine 50.0 ml Distilled water to 5930.0 ml.

(Solution B-3) 3.5N ammoniacal silver nitrate aqueous solution (pH adjusted to 9.0 with ammonium nitrate) (Solution C-3) 3.5N potassium bromide aqueous solution containing 4.0% by weight of gelatin (Solution D-3 ) Fine grain emulsion consisting of 3% by weight of gelatin and silver iodide grains (average grain size: 0.05 μm) 0.844 mol * The preparation method is shown below.

6.0% by weight containing 0.06 mol of potassium iodide
2000 ml of an aqueous solution containing 7.06 mol of silver nitrate and 7.06 mol of potassium iodide in 5000 ml of gelatin solution.
Added over 10 minutes. The pH during fine particle formation was controlled to 2.0 using nitric acid, and the temperature was controlled to 40 ° C. After forming the particle size, the pH was adjusted to 6.0 using an aqueous sodium carbonate solution.

(Solution E-3) A fine grain emulsion composed of silver iodobromide grains (average grain size 0.04 μm) containing 1 mol% of silver iodide, prepared in the same manner as the above silver iodide fine grain emulsion 2.20 Mol (however, the temperature during fine particle formation was controlled at 3.0 ° C.) (Solution F-3) 1.75N potassium bromide aqueous solution (Solution G-3) 56 wt% acetic acid aqueous solution The temperature was kept at 70 ° C. in the reaction vessel ( Solution A-3), (Solution B
-3), (Solution C-3) and (Solution D-3) were added by the simultaneous mixing method over a time period of 163 minutes, and then (Solution E-3) was independently controlled for 12 minutes at a constant rate. Seed crystals were grown to 1.0 μm.

Here, (solution B-3) and (solution C-
The addition rate of 3) is changed in a function-like manner with respect to time so as to be commensurate with the critical growth rate, so that the addition rate is appropriate so as not to cause polydispersion due to generation of small particles other than growing seed crystals and Ostwald ripening. Added in. (Solution D-3) That is, the silver iodide fine grain emulsion was supplied by changing the rate ratio (molar ratio) with the aqueous ammoniacal silver nitrate solution with respect to the particle size as shown in Table 2 to obtain a core having a multiple structure. A / shell type silver halide emulsion was prepared.

By using (Solution F-3) and (Solution G-3), pAg and pH during crystal growth were controlled as shown in Table 2. The pAg and pH were measured by a conventional method using a silver sulfide electrode and a glass electrode. After particle formation,
Desalting treatment was performed according to the method described in JP-A-5-34851, gelatin was then added and redispersed, and the pH was adjusted to 40 ° C.
5.80 and pAg were adjusted to 8.06.

When the obtained emulsion grains were observed with an electron microscope, they consisted of 100% twin grains, the twin ratio having two or more parallel twin planes was 85%, the distribution was 10%, and the average grain size was 1.0
It consisted of slightly distorted octahedral twin monodisperse grains of μm.

[0086]

[Table 2]

Example 2 Emulsions A to J were prepared by the method described below. However, in the following method, no pH adjusting solution was added, except that the pH value was adjusted using an appropriate pH adjusting solution during pH adjustment. The ripening time was optimized for each emulsion (the best result was obtained in the evaluation of fog-sensitivity). The amount of various additives (sodium thiosulfate, sensitizing dye, chloroauric acid, ammonium thiocyanate) added is in the range of 0.75 to 1.25 times the amount used when preparing the comparative emulsion, and the optimum amount for each emulsion is selected. Was added.

<< Preparation of Comparative Emulsion A >> A part of Emulsion Em-1 was dissolved by heating at 50 ° C. to adjust pH to 5.80, and then 52.6 mg of sensitizing dye (sd-1) per mol of silver halide. ,
65.77 mg of (sd-2) and 85.5 mg of (sd-3) were added. 20 minutes after the addition of the sensitizing dye, 5 × 10 ⁻⁶ mol of sodium thiosulfate pentahydrate was added per mol of silver halide,
Then, 1.42 × 10 ⁻⁶ mol of chloroauric acid and 3.15 × 10 ⁻⁴ mol of ammonium thiocyanate were added and the mixture was aged for an appropriate time.

At the end of aging, 4-hydroxy-6-methyl- (1,
Emulsion A was obtained by adding 3,3a, 7) -tetrazaindene as a stabilizer and cooling and solidifying.

[0090]

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<Preparation of Emulsion B> Emulsion B was prepared in the same manner as Emulsion A except that ammonium thiocyanate was added and 20 minutes later, the pH was adjusted to 6.3 and the mixture was aged for an appropriate time. Obtained.

<< Preparation of Emulsion C >> 20 minutes after the addition of ammonium thiocyanate, the pH was adjusted to 6.3, and further 20 minutes later.
Emulsion C was obtained in the same manner as Emulsion A except that the pH was adjusted to 6.8 and the ripening was carried out for an appropriate time.

<Preparation of Emulsion D> Emulsion A except that ammonium thiocyanate was added, pH was adjusted to 6.3 after 20 minutes, ripening was continued for an appropriate time, and pH was adjusted to 5.8 5 minutes before the completion of ripening. Emulsion D was obtained in the same manner as in Preparation of.

<< Preparation of Emulsion E >> Sensitizing dye (sd-1)
An emulsion E was obtained in the same manner as the preparation of the emulsion A except that the pH was adjusted to 5.3 17 minutes after the addition of (sd-2) and (sd-3).

<Preparation of Emulsion F> Emulsion A except that the pH was adjusted to 5.0 3 minutes before the addition of sodium thiosulfate, and the pH was adjusted to 6.0 30 minutes after the addition of ammonium thiocyanate.
Emulsion F was obtained in the same manner as in Preparation of.

<< Preparation of Emulsion G >> 50 parts of emulsion Em-1 was used.
After dissolving by heating at ℃ and adjusting the pH to 6.30, 52.6 mg (sd-1) of sensitizing dye (sd-1) per mol of silver halide
-2) 65.77 mg and (sd-3) 85.5 mg were added. The pH was adjusted to 5.8 17 minutes after the addition of the sensitizing dye, and 3 minutes later, 5 × 10 ^-6 mol of sodium thiosulfate pentahydrate was added per 1 mol of silver halide, and then 1.42 × 10 4 chloroauric acid. ^-6 mol and ammonium thiocyanate 3.15 × 10 ^-4 mol were added and the mixture was aged for a suitable time.

At the end of aging, 4-hydroxy-6-methyl- (1,
Emulsion G was obtained by adding 3,3a, 7) -tetrazaindene as a stabilizer and cooling and solidifying.

<Preparation of Emulsion H> Emulsion H was prepared in the same manner as Preparation of Emulsion G except that pH was adjusted to 6.3 20 minutes after the addition of ammonium thiocyanate and the mixture was aged for an appropriate time.

<< Preparation of Emulsion I >> 17 minutes after the addition of the sensitizing dye
Adjust the pH to 5.3 and add ammonium thiocyanate to 20
Emulsion I was obtained in the same manner as Emulsion G except that the pH was adjusted to 5.8 minutes.

<< Preparation of Emulsion J >> 20 minutes after the pH was adjusted to 5.8 20 minutes after the addition of ammonium thiocyanate
Adjust the pH to 6.3, and adjust the pH 5 minutes before the end of chemical sensitization.
Emulsion J was prepared in the same manner as Emulsion I except that it was adjusted to 5.8.
I got

Preparation of Single Emulsion Layer Coating Samples 101 to 110 Emulsions A to J obtained as described above were coated according to the following coating formulation.
The triacetyl cellulose film subjected to the undercoating is applied as a support on this and dried, and coated samples 101 to 110
Was produced.

<Coating Formulation> In order from the support side, the first layer: green-sensitive silver halide emulsion layer Emulsion silver coating amount 2.5 g / m ² magenta coupler (MI) 0.01 mol per 1 mol of silver Colored magenta coupler (CM-I) 0.005 mol to 1 mol of silver DIR compound (DI) 0.0002 mol to 1 mol of silver HBS-I (tricresyl phosphate: TCP) 0.22 g / m ² Second layer: yellow filter layer Yellow Emulsified dispersion of colloidal silver and 2,5-di-t-octylhydroquinone and HI (2,4-dichloro-6-hydroxy-s-triazine sodium salt)

[0103]

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(Evaluation of Sensitometry) The coated samples 101 to 110 obtained as described above were subjected to wedge exposure using green light, and then processed in the following processing steps to obtain a characteristic curve, and a relative sensitivity (fog density). The reciprocal of the exposure amount that gives a density of +0.15 is represented by a relative value with the sample 101 being 100).

Processing step (38 ° C.) Color development (2 minutes 50 seconds) → bleaching (6 minutes 30 seconds) → washing (3 minutes
15 seconds) -fixing (6 minutes 30 seconds) -washing (3 minutes 15 seconds) -stabilization (1 minute 30 seconds) -drying The composition of the processing liquid used in each processing step is as follows.

<Color developer> 4-amino-3-methyl-N-ethyl-N- (β-hydroxyethyl) aniline / sulfate 4.75 g anhydrous sodium sulfite 4.25 g hydroxylamine / 1/2 sulfate 2.0 g anhydrous Potassium carbonate 37.5 g Sodium bromide 1.3 g Nitrilotriacetic acid trisodium salt (monohydrate) 2.5 g Potassium hydroxide 1.0 g Add water to make 1 liter and adjust to pH = 10.0.

<Bleach> Ethylenediaminetetraacetic acid ammonium salt 100.0 g Ethylenediaminetetraacetic acid diammonium salt 10.0 g Ammonium bromide 150.0 g Glacial acetic acid 10.0 g Water was added to make 1 liter, and pH was adjusted to 6.0 using ammonia water. To do.

<Fixer> Ammonium thiosulfate 175.0 g Anhydrous sodium sulfite 8.5 g Sodium metasulfite 2.3 g Water is added to make 1 liter, and pH is adjusted to 6.0 using acetic acid.

<Stabilizer> Formalin (37% aqueous solution) 1.5 cc. Conidax (Konica Corporation) 7.5 cc. Add water to make 1 liter.

Further, two sets of Samples 101 to 110 were prepared and subjected to wedge exposure using green light, and one set was stored for 5 days at 40 ° C., 55% RH temperature and humidity, and the remaining 1 The set was stored in a freezer as a control, and the same development processing as above was performed to evaluate the latent image storability. The latent image storability was evaluated as a relative value by taking the reciprocal of the exposure amount giving a fog density + 0.15 density as the sensitivity from the characteristic curve for each sample and setting the sensitivity of each control sample as 100.

Table 3 for relative sensitivity and latent image storability of green color
Shown in

[0112]

[Table 3]

As is apparent from the table, the emulsion p
By changing H, an emulsion having excellent sensitivity and latent image storability was obtained. In particular, the emulsions obtained by subjecting samples 106, 108 to 110 to a pH higher than that of the chalcogen sensitizer when the sensitizing dye was added, and increasing the pH after the chalcogen sensitizer was added. Showed extremely excellent performance. Further, it can be seen that those having a difference between the maximum value and the minimum value of pH of 1.0 or more are more effective than those having no difference.

Example 3 Emulsions K to O were prepared by the following method.

<< Preparation of Comparative Emulsion K >> A part of Emulsion Em-2 was dissolved by heating at 50 ° C. and the pH was adjusted to 5.80. Then, sodium thiosulfate pentahydrate 3.8 × 1 was added per mol of silver halide.
0 ^-6 mol was added, and then 1.12 × 10 ^-6 mol of chloroauric acid and 2.79 × 10 ^-4 mol of ammonium thiocyanate were added and the mixture was aged for an appropriate time. Twenty minutes before the completion of ripening, 52.6 mg of sensitizing dye (sd-1), (sd-
2) Add 65.77 mg and (sd-3) 85.5 mg, and add 4-hydroxy-6-methyl- (1,3,3a, 7) -tetrazaindene as a stabilizer at the end of aging, and allow to cool and solidify. Emulsion K was obtained.

<< Preparation of Emulsion L >> Emulsion L was prepared in the same manner as the preparation of emulsion K except that the pH was adjusted to 6.3 3 minutes before the addition of the sensitizing dye.

<Preparation of Emulsion M> The procedure of preparation of Emulsion K was repeated except that the pH was adjusted to 6.3 20 minutes after the addition of ammonium thiocyanate, and the pH was adjusted to 6.8 3 minutes before the addition of the sensitizing dye. Emulsion M was obtained.

<< Preparation of Emulsion N >> 3 minutes before the addition of the sensitizing dye
The pH was adjusted to 6.3, and 4-hydroxy-6-methyl- (1,3,3
Emulsion N was obtained in the same manner as Emulsion K except that the pH was adjusted to 5.8 3 minutes before the addition of a, 7) -tetrazaindene.

<< Preparation of Emulsion O >> After dissolution of emulsion Em-2
Adjust the pH to 5.3 and add ammonium thiocyanate to 20
After 5 minutes, adjust the pH to 5.8, ripen for an appropriate time, and adjust the pH to 6.3 3 minutes before adding the sensitizing dye,
Emulsion O was obtained in the same manner as Emulsion K except that pH was adjusted to 5.8 3 minutes before the addition of -6-methyl- (1,3,3a, 7) -tetrazaindene.

Preparation and Evaluation of Single Emulsion Layer Coated Samples 201-205 Coating samples 201-205 were prepared in the same manner as in Example 1 using the obtained emulsions KO, and evaluated in the same manner as in Example 1. The results obtained are shown in Table 4.

[0121]

[Table 4]

From this, it can be seen that an emulsion excellent in sensitivity and latent image storability can be obtained by changing the pH during sensitization. In particular, it can be seen that those having a difference between the maximum value and the minimum value of pH of 1.0 or more are more effective than those having no difference.

Example 4 Emulsions P to T were obtained by the method described below.

<< Preparation of Comparative Emulsion P >> A part of Emulsion Em-1 was dissolved by heating at 50 ° C. and adjusted to pH 5.8, and then 45 mg of sensitizing dye (sd-1) per mol of silver halide, ( sd-
2) 62 mg and (sd-3) 92.5 mg were added. Its After 20 minutes, sodium thiosulfate pentahydrate 4.0 × 10 ^-6 mol, added selenium sensitizer (Se-1) 1.0 × 10 -6 mol, then 1.42 × 10 ^-6 mol of chloroauric acid, thiocyanate Ammonium 3.10
Add 10 ^-4 mol × 10 ^-4 mol and ripen for an appropriate time. At the end of ripening, add 4-hydroxy-6-methyl- (1,3,3a, 7) -tetrazaindene as a stabilizer to solidify by cooling and emulsion. P was prepared.

[0125]

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<< Preparation of Emulsion Q >> Emulsion Q was prepared in the same manner as preparation of emulsion P except that pH was adjusted to 6.3 20 minutes after addition of ammonium thiocyanate.

<Preparation of Emulsion R> Emulsion R was prepared in the same manner as Preparation of Emulsion P except that pH was adjusted to 5.0 3 minutes before the addition of sodium thiosulfate.

<Preparation of Emulsion S> Emulsion E was prepared in the same manner as emulsion P except that pH was adjusted to 5.0 3 minutes before the addition of sodium thiosulfate and pH was adjusted to 5.5 30 minutes after the addition of ammonium thiocyanate. I got S.

<< Preparation of Emulsion T >> After dissolution of Emulsion Em-2
Adjust the pH to 6.3, 3 minutes before adding sodium thiosulfate
Adjust the pH to 5.3 and add ammonium thiocyanate to 20
PH was adjusted to 5.8 after 20 minutes, pH was adjusted to 6.3 after 20 minutes, and pH was adjusted to 5.8 3 minutes before the addition of 4-hydroxy-6-methyl- (1,3,3a, 7) -tetrazaindene. Emulsion P except when adjusting to
Emulsion T was obtained in the same manner as in Preparation of.

Preparation and Evaluation of Single Emulsion Layer Coated Samples 301-305 Coating samples 301-305 were prepared in the same manner as in Example 1 using the obtained emulsions P-T, and evaluated in the same manner as in Example 1. The results obtained are shown in Table 5.

[0131]

[Table 5]

It is also possible to obtain an emulsion excellent in sensitivity and latent image storability by changing pH during sensitization.
Further, as in Samples 304 and 305, the pH when the sensitizing dye is added is higher than that when the chalcogen sensitizer is added, and the emulsion obtained by going through the step of increasing the pH after adding the chalcogen sensitizer is It is understood that it has extremely excellent performance.

Example 5 On a subbed cellulose triacetate film support,
A multilayer color light-sensitive material consisting of the layers shown below (composition of light-sensitive material constituent layers) was prepared and designated as Sample 401. The amount of the additive used is the amount expressed in g / m ² unit in terms of silver per 1 m ² of the light-sensitive material for silver halide and colloidal silver, and for the sensitizing dye, the halogenation in the same layer. The number of moles per 1 mole of silver and the amount of other additives such as couplers expressed in g / m ² unit per 1 m ² of the light-sensitive material are shown.

(Composition of Photosensitive Material Constituent Layer) First Layer: Antihalation Layer Black Colloidal Silver 0.16 Ultraviolet Absorber (UV-1) 0.20 High Boiling Solvent (OIL-1) 0.16 Gelatin 1.60 Second Layer: Intermediate Layer Compound ( SC-1) 0.14 High boiling point solvent (OIL-2) 0.17 Gelatin 0.80 Third layer: low sensitivity red sensitive layer Silver iodobromide emulsion IA 0.15 Silver iodobromide emulsion IB 0.35 Sensitizing dye (SD-1) 2.0 × 10 ^-4 Sensitizing dye (SD-2) 1.4 × 10 ^-4 Sensitizing dye (SD-3) 1.4 × 10 ^-5 Sensitizing dye (SD-4) 0.7 × 10 ^-4 Cyan coupler (C-1) 0.53 Colored Cyan coupler (CC-1) 0.04 DIR compound (D-1) 0.025 High boiling point solvent (OIL-3) 0.48 Gelatin 1.09 4th layer: Medium-sensitive red sensitive layer Silver iodobromide emulsion IB 0.30 Silver iodobromide emulsion IC 0.34 sensitizing dye (SD-1) 1.7 × 10 -4 sensitizing dye (SD-2) 0.86 × 10 -4 sensitizing dye (SD- ) 1.15 × 10 ^-5 Sensitizing dye (SD-4) 0.86 × 10 -4 Cyan coupler (C-1) 0.33 Colored cyan coupler (CC-1) 0.013 DIR compound (D-1) 0.02 High boiling solvent (OIL- 1) 0.16 gelatin 0.79 Fifth layer: high-sensitivity red-sensitive layer Silver iodobromide emulsion ID 0.95 Sensitizing dye (SD-1) 1.0 × 10 ⁻⁴ Sensitizing dye (SD-2) 1.0 × 10 ⁻⁴ Sensitizing dye (SD-3) 1.2 × 10 ^-5 Cyan coupler (C-2) 0.14 Colored cyan coupler (CC-1) 0.016 High boiling point solvent (OIL-1) 0.16 Gelatin 0.79 Sixth layer: Intermediate layer Compound (SC-1) 0.09 High boiling point solvent (OIL-2) 0.11 Gelatin 0.80 7th layer: Low sensitivity green sensitive layer Silver iodobromide emulsion IA 0.12 Silver iodobromide emulsion IB 0.38 Sensitizing dye (SD-4) 4.6 × 10 ^-5 sensitization Dye (SD-5) 4.1 × 10 ^-4 Magenta coupler (M-1) 0.14 Magenta coupler (M-2) 0.14 Color Doma Zenta coupler (CM-1) 0.06 High boiling point solvent (OIL-4) 0.34 Gelatin 0.70 Eighth layer: Intermediate layer Gelatin 0.41 Ninth layer: Medium sensitivity green sensitive layer Silver iodobromide emulsion IB 0.30 Silver iodobromide emulsion IC 0.34 Sensitizing dye (SD-6) 1.2 × 10 ^-4 Sensitizing dye (SD-7) 1.2 × 10 ^-4 Sensitizing dye (SD-8) 1.2 × 10 ^-4 Magenta coupler (M-1) 0.04 Magenta coupler ( M-2) 0.04 Colored magenta coupler (CM-1) 0.017 DIR compound (D-2) 0.025 DIR compound (D-3) 0.002 High boiling point solvent (OIL-4) 0.12 Gelatin 0.50 10th layer: High sensitivity green sensitive layer Emulsion A 0.95 Magenta coupler (M-1) 0.09 Colored magenta coupler (CM-1) 0.011 High boiling point solvent (OIL-4) 0.11 Gelatin 0.79 11th layer: Yellow filter layer Yellow colloidal silver 0.08 Compound (SC-1) 0.15 High Boiling point solvent (OIL- ) 0.19 Gelatin 1.10 12th layer: low sensitivity blue-sensitive layer Silver iodobromide emulsion IA 0.12 iodobromide emulsion IB 0.24 iodobromide emulsion IC 0.12 Sensitizing dye (SD-9) 6.3 × 10 -5 Sensitizing dye (SD-10) 1.0 × 10 ^-5 Yellow coupler (Y-1) 0.50 Yellow coupler (Y-2) 0.50 DIR compound (D-4) 0.04 DIR compound (D-5) 0.02 High boiling point solvent (OIL-2) 0.42 Gelatin 1.40 13th layer: High-sensitivity blue-sensitive layer Silver iodobromide emulsion IC 0.15 Silver iodobromide emulsion IE 0.80 Sensitizing dye (SD-9) 8.0 × 10 ^-5 Sensitizing dye (SD-11) 3.1 × 10 ^-5 Yellow coupler (Y-1) 0.12 High boiling point solvent (OIL-2) 0.05 Gelatin 0.79 14th layer: First protective layer Silver iodobromide emulsion IF 0.40 Ultraviolet absorber (UV-1) 0.065 High boiling point solvent (OIL) -1) 0.07 High boiling point solvent (OIL-3) 0.07 Gelatin 0.65 15th layer: 2nd protective layer Alkali-soluble mat (Average particle diameter 2 [mu] m) 0.15 Polymethyl methacrylate (average particle size 3 [mu] m) 0.04 Slip agent in addition to the (WAX-1) 0.04 Gelatin 0.55 In addition the compositions, coating aid Su-1, dispersion aid Su
-2, viscosity modifier, hardener H-1, H-2, stabilizer ST
-1, antifoggant AF-1, two types of AF-2 having an average molecular weight of 10,000 and an average molecular weight of 1,100,000, and preservative DI-1 were added.

The emulsions used for the above samples are as follows. The average particle size is shown as a particle size converted into a cube.
Further, each emulsion was optimally subjected to gold / sulfur sensitization.

[0136]

[Table 6]

[0137]

[Chemical 4]

[0138]

Embedded image

[0139]

[Chemical 6]

[0140]

[Chemical 7]

[0141]

Embedded image

[0142]

[Chemical 9]

[0143]

[Chemical 10]

[0144]

[Chemical 11]

[0145]

[Chemical 12]

[0146]

[Chemical 13]

In Sample 401, Emulsion B prepared in Example 2 was used instead of Emulsion A in the tenth layer of the high-sensitivity green sensitive layer.
-J were used to prepare samples 402-410.

(Evaluation of Sensitometry) The coated samples 401 to 410 obtained as described above were wedge-exposed for 0.01 seconds using white light, and then treated with the same treatment solution as that used in Example 1. By using the following processing steps, a characteristic curve relating to the green density was obtained, and the relative sensitivity (the reciprocal of the exposure amount giving the fog density + 0.1 is represented by a relative value with the sample 401 being 100) was obtained.

Processing step (38 ° C.) Color development (3 minutes 15 seconds) → bleaching (6 minutes 30 seconds) → washing (3 minutes
15 seconds) -Fixing (6 minutes 30 seconds) -Washing (3 minutes 15 seconds) -Stabilization (1 minute 30 seconds) -Drying Further, two sets of samples 401 to 410 are prepared and subjected to wedge exposure using white light. After that, one set was stored for 5 days under the conditions of temperature and humidity of 40 ° C and 55% RH, and the remaining one set was stored in a freezer as a control, and the same development processing as above was performed to preserve latent images. Was evaluated. The latent image storability was evaluated as a relative value by taking the reciprocal of the exposure amount giving a fog density + 0.1 from the characteristic curve for each sample as the sensitivity, and setting the sensitivity of each control sample to 100.

Table 7 for green relative sensitivity and latent image storability
Shown in

[0151]

[Table 7]

As is apparent from the table, even in the color negative system of multi-layer coating, the sample according to the present invention has high sensitivity and excellent latent image storability. It can be seen that the effect of the sample using the emulsion obtained by going through the step of increasing the pH after the addition of the chalcogen sensitizer is higher than that of the time, and is remarkable.

Further, it can be seen that those having a difference between the maximum value and the minimum value of pH of 1.0 or more are more effective than those having no difference.

[0154]

According to the present invention, a silver halide photographic light-sensitive material having high sensitivity and excellent latent image storability can be obtained.

Claims (6)

[Claims] 1. A photographic silver halide emulsion formed by changing the pH of the system from the start of at least one selected from spectral sensitization and chemical sensitization to the end of both. . 2. The photographic silver halide emulsion according to claim 1, which is formed through a step of increasing pH after adding the chalcogen sensitizer. 3. The pH when the spectral sensitizing dye is added is higher than the pH when the chalcogen sensitizer is added.
Or a silver halide emulsion for photography according to item 2. 4. The difference between the minimum value and the maximum value of pH between the start and the end of at least one selected from spectral sensitization and optical sensitization is 1.0 or more. The photographic silver halide emulsion according to claim 1, 2 or 3. 5. A silver halide emulsion comprising grains sensitized by reduction inside the silver halide emulsion.
Or a silver halide emulsion for photography according to item 4. 6. A silver halide photographic light-sensitive material containing the silver halide emulsion according to claim 1.