JP2934607B2 - Silver halide photographic material containing silver bromide or silver bromoiodide emulsion having triangular tabular grains - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a silver halide emulsion containing triangular tabular crystals, a method for producing the same, and a photosensitive silver halide photographic material containing the emulsion.

BACKGROUND OF THE INVENTION The effects of various precipitation conditions on the formation of silver halide emulsions containing tabular crystals have been extensively studied as the tabular grains have been known in photography for some time. . As early as 1961, Berry et al. Photo
graphic Science and Engineering, Vol. 5, No.
No. 6 reported the production and growth of tabular silver bromoiodide grains. For a discussion of tabular grains, see Focal Press 1966, Du.
ffin, Photographic Emulsion Chemistry 66
~ Page 72. Earlier patent documents include US-A4
063951, US-A 4067739, US-P41
50994, US-P4184877 and US-P41
84878. However, the tabular grains described therein cannot be regarded as exhibiting a high diameter to thickness ratio commonly referred to as the aspect ratio. Many U.S. applications filed in 1981 and issued in 1984,
For example, US-A 4,434,226, US-A 4,439,952
0, US-A 4,425,425, US-A 4,425,426
And U.S. Pat. No. 4,433,048 describe tabular grains having a high aspect ratio and their advantages in photographic applications. Research on high aspect ratio silver halide emulsions is described in Research Disclosure, Vols.
Found in Item 22534, January 3rd. The above references for tabular grains mainly relate to high speed silver bromide or silver iodobromide emulsions.

The anisotropic growth of the tabular grains is due to the formation of parallel twin planes during the precipitation nucleation step.

The shape of tabular grains can be varied in various ways, such as triangular,
Hexahedral, discoid, tetrahedral and even acicular particles can be formed. Said features can be regular or irregular.

[0005] The appearance of triangular or hexahedral particles is mainly related to the number of twin planes: odd numbers of twin planes result in triangular shapes of the grains, while even numbers result in hexahedral shapes, while quadrilateral and needle-shaped particles. Is associated with coalescence or the formation of non-parallel twin planes. These issues are discussed in J. Imag. Sci.
1 (1987) pp. 15-26 and 93-99.

[0006] The preparation of tabular grain emulsions by methods well known to those skilled in the art of photography results in a grain population consisting of a mixture of all forms of the crystals described above.

As a result, many schemes have been developed to improve crystal size and shape homogeneity. In this connection, EP-A566606, EP-A50694
7, EP-A 518 066, EP-A 513 722 and US Pat. No. 4,797,354 relate to the production of monodisperse hexahedral tabular crystals, each relating to the production of tabular emulsions having a high percentage (at least 90%) of hexahedral tabular crystals.

However, a method for producing an emulsion having a homogeneous crystal distribution composed of thin tabular triangular silver bromide or silver bromoiodide crystals has never been disclosed yet.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide a triangular tabular emulsion, a process for preparing said emulsion, and a silver halide photographic material comprising an emulsion having silver bromide or silver bromoiodide triangular tabular grains. It is in.

[0010] Other objects will become apparent from the following description.

SUMMARY OF THE INVENTION According to the present invention, there is provided a photosensitive silver bromide or silver bromoiodide emulsion containing silver bromide or silver bromoiodide triangular tabular grains and hexahedral tabular grains. 0.3 μm
Having an average grain thickness of less than, an average diameter of a circle having the same area of at least 0.6 μm, an average aspect ratio of at least 2: 1, a coefficient of variation of less than 40%, and wherein said triangular tabular grains have a total projected area of In a photosensitive silver bromide or silver bromoiodide emulsion which accounts for at least 30% of the total number of grains, the number of triangular tabular grains is from 25% to 55%, and Ratio of the thickness of the particles (t _tr
/ T _hex ) is from 1.3 to 0.7, and a photosensitive silver bromide or silver bromoiodide emulsion is provided.

According to the present invention: (1) silver nitrate and silver nitrate in the presence of at least one onium compound, preferably a phosphonium compound, and preferably in the presence of at least one protective colloid which is gelatin and / or colloidal silica; Precipitating silver bromide or silver bromoiodide by a double or triple jet method applied to an aqueous solution of a halide salt, wherein the weight ratio of onium compound to protective colloid is 0.03-0.50, and (2) In the above step, a constant pAg value in the range of 9.5 to 8.0, more preferably 9.5 to 8.8, and silver nitrate and halogen Controlling the nucleation and growth steps by a variable flow rate of the aqueous solution of the halide salt; (3) at least one physics between at least the nucleation step and the first growth step (4) A method for producing an emulsion containing the triangular tabular grains as described above, which comprises a step of desalting the reaction medium, redispersing the silver halide, and chemically ripening the silver halide grains. Provide further.

The present invention also provides a support and at least one hydrophilic colloid layer containing at least one photosensitive emulsion containing triangular tabular silver bromide or silver bromoiodide grains as described above. Also provided are silver halide light-sensitive photographic materials.

DETAILED DISCLOSURE OF THE INVENTION For all crystals having a triangular plate-like shape according to the invention, said shape is such that the length of the smallest side is 1 / the length of the largest side.
If it is less than 10, it is considered a triangle. According to the present invention there is provided an emulsion containing triangular tabular silver bromide or silver bromoiodide grains, wherein said tabular grains comprise at least 2:
It has an aspect ratio of 1. The term aspect ratio refers to the thickness of the silver bromide or silver bromoiodide triangular tabular grains of the present invention, which is the diameter of a circle having the same area as two parallel major surfaces and the distance between the two parallel surfaces. Applicable when the crystal has two parallel major surfaces with a ratio between at least equal to 2: 1. More preferably, the aspect ratio is at least 5: 1, and even more preferably at least 8: 1, wherein an average crystal diameter of at least 0.6 μm is preferred, and a crystal thickness of less than 0.3 μm is preferred. .2μ
More preferably, the coefficient of variation is less than 40%, more preferably less than 25%.

[0015] For radiographic purposes, the main photographic advantages of tabular grains compared to conventional spherical grains are high coverage at high cure levels, high developability and especially in double-side coated spectral sensitized materials. There is sharpness.

The light-sensitive silver halide emulsion containing tabular grains, in particular the triangular tabular grains according to the present invention, contains 0.03% of an onium compound and a protective colloid in a nucleation and / or growth step in a production step. Weight ratio of ~ 0.5 (CO
SI) amount, more preferably the presence of a weight ratio amount of 0.05 to 0.30, and 9.5 to 8.0, more preferably 9.
It is characterized by a well-defined pAg value range of 5-8.8.

For emulsions made by the method of the present invention, the thickness ratio of triangular tabular crystals to hexahedral tabular crystals is:
As is clear from the examples, it is 1.3 to 0.7.
This is in contrast to the thickness ratio obtained by application of the precipitation method according to FR 2534036, for example, when said triangular crystals are made by the method of the invention, growth crystals for triangular crystals are observed which are similar to those for hexahedral crystals. Means that

As the protective colloid, gelatin or colloidal silica sol alone or in combination with gelatin and colloidal silica sol is used in the process of the present invention. However, some or all can be replaced by synthetic, semi-synthetic or natural polymers. Synthetic alternatives to gelatin include, for example, polyvinyl alcohol, poly-N-vinylpyrrolidone, polyvinylimidazole, polyvinylpyrazole, polyacrylamide, polyacrylic acid and their derivatives, especially their copolymers. Natural substitutes for gelatin include other proteins such as zein, albumin and casein, cellulose, saccharides, starch, and alginates. In general, semi-synthetic alternatives to gelatin include modified natural products, such as gelatin derivatives and celluloses obtained by converting gelatin with alkylating or acylating agents, or by grafting polymerizable monomers onto gelatin. There are derivatives such as hydroxyalkyl cellulose, carboxymethyl cellulose, phthaloyl cellulose, and cellulose sulfate. Gelatin can be lime-treated or acid-treated gelatin. Such gelatin species are described, for example, in Academic Press 19
Published in 1977, edited by AG Ward and A. Courts, The S
It is described on page 295 of the Science and Technology of Gelatin and the next page. Gelatin is also Bull. Soc. Sci.
Gelatin can be treated with an enzyme as described in Phot. Japan. No. 16, page 30 (1966).

In a most preferred embodiment, the method of the present invention uses silica sol as the sole protective colloid in the preparation of silver halide emulsions, or with gelatin as described above. Commercially available silica sols include Syton silica sols (Monsanto Inorgan
ic Chemicals Div.), Ludex silica sol (trademark product of du Pont de Nemours & Co., Inc.), Nalco and Nalcoag silica sol (Nalco Chemic
al Co.), Snowtex silica sol (Nissan
Kagaku KK trademark product) and Kieselsol, Type 1
00, 200, 300, 500 and 600 (Bayer AG
Trademark products). The particle size of the silica sol particles is 3 nm
Small particles in the range of ３０30 μm, but in the range of 3 nm to 0.3 μm are preferred.

The change from the weight ratio of the protective colloid to the co-stabilized onium compound during the production process which characterizes the production process of the present invention is the fact that at least two portions of said compound during the production process of the triangular tabular crystals according to the present invention. Can be achieved by adding Since NH ₄ Br can be used as a halide salt in the method for producing emulsion grains of the present invention, NH ₄
⁺ Ions are excluded as onium compounds.

Since thin triangular tabular grains provide the above-mentioned advantages to a large extent, as protective colloids according to the invention, preference is given to particles comprising silica having an average particle thickness of less than 0.3 μm, preferably less than 0.2 μm. More preferred. Thinner silver halide emulsion grains containing silica readily exhibit larger aspect ratios, so that for grains according to the present invention, an average aspect ratio of at least 5: 1, more preferably at least 8: 1, Still more preferably, an average aspect ratio of at least 12: 1 is preferred.

For emulsions containing triangular tabular grains of silver bromide or silver bromoiodide according to the present invention, a total projected area of at least 70% of said grains is highly preferred, at least 90%.
% Is more preferred.

Iodine ions are described, for example, in EP-A05614.
15, EP-A0563701, EP-A056370
8, EP-A0649052 and EP-A065128
As described in No. 4, it can be obtained by inorganic iodide salts and / or organic compounds which release iodide ions. An iodine ion concentration of 10 mol% or less can be present, but a concentration of 3 mol% or less is particularly preferred.

The preparation of the photosensitive triangular tabular silver bromide or silver bromoiodide emulsion according to the present invention comprises the following steps:

(1) Silver halide by a double-jet or triple-jet method applied to an aqueous solution of silver nitrate and halide salts in a protective colloid, preferably silica and / or gelatin, in the presence of at least one onium compound. (In this case, the weight ratio of the onium compound to the protective colloid is 0.03 to 0.50, more preferably 0.05 to 0.30 ) ;

(2) nucleation and nucleation with a constant pAg value in the range of 9.5 to 8.0, more preferably 9.5 to 8.8, and a variable flow rate of an aqueous solution of silver nitrate and halide salts during said process; Controlling the growth process;

(3) at least one physical ripening step between at least the nucleation step and the first growth step;

(4) desalting the reaction medium and redispersing the silver halide;

(5) A step of chemically ripening silver halide crystals.

Less than 10% by weight, more preferably 0.5-5.0% by weight, of the total amount of silver nitrate is added during the nucleation step . This step preferably comprises adding by a double jet method of halide salt and silver nitrate at a pBr of at least 2.0.

The additional amounts of protective colloid and onium compound may be added to the reaction vessel in one or more portions or continuously by triple jet precipitation. Particularly preferred is, for example, the addition during the so-called Ostwald ripening stage before the flow rate of the silver and / or halide solution is increased by a double jet precipitation method.

With the exception of ammonium compounds such as, for example, ammonium bromide, the following compounds represented by the general formula can be used as onium compounds:

[0033] ^A + X ^- wherein X ^- is an anion, ^{A +} represents an onium ion selected from any of the following general formula:

[0034]

Embedded image

Wherein R ₁ and R ₃ are the same or different,
Represents hydrogen (excluding ammonium), an alkyl group, a substituted alkyl group, a cycloalkyl group, an aryl group, or a substituted aryl group, wherein R ₂ is any of the groups represented by R ₁ and R ₃ , or R ₁ or Together with any of R ₃ represents the atoms necessary to close the heterocyclic nucleus.

The onium ion may be (1) added to the polymer chain or (2) a divalent organic bonding group such as —O—, —S—, —SO ₂
- etc. any other onium structure Kakaru through, or (3) is directly bonded to any of the groups represented by R _1.

An example of a suitable onium compound is US-A30
17270. In the above specification, trialkylsulfonium salts, polysulfonium salts, tetraalkyl quaternary ammonium salts, quaternary ammonium salts in which a quaternary nitrogen atom is part of a ring system, such as quaternary ammonium and phosphonium and bisquaternary salts Preferred examples of the cationic polyalkylene oxide salt containing are described.

According to the present invention, the onium compound is
Acts as an effective crystal habit modifier for silver bromide and silver bromoiodide triangular tabular crystals. The effect of the onium compound as a crystal habit modifier is not negligible in the presence of colloidal silica sol in the presence of gelatin, but is further emphasized in the presence of colloidal silica sol.

Photographic emulsions containing silver bromide and silver bromoiodide triangular tabular crystals according to the present invention can have a homogeneous or heterogeneous halide distribution within the crystal volume. Heterogeneous halide distribution may be achieved by the application of a growth step having a different halide composition or by a conversion step, e.g., by reducing the poorly soluble silver salts on tabular iodide-existing silver bromoiodide or silver bromide cores present. It can be obtained by adding iodine ions provided. In the case of a heterogeneous distribution of bromide and iodide ions, a multilayer particle structure is obtained. Clearly tabular triangles must be maintained in this case in order to obtain triangular tabular emulsion crystals according to the invention.

The crystal can be any dope, for example R
It can be doped with h ³⁺ , Ir ⁴⁺ , Cd ²⁺ , Zn ²⁺ , Ru ²⁺ and Pb ²⁺ .

During precipitation, a grain growth inhibitor or accelerator can be added to obtain crystals having a preferred average crystal diameter of 0.05 to 5 μm. Examples of particle growth promoters include, for example, compounds bearing a thioether functional group.

The nucleation step is formed by controlling the pAg value and the preferred increase in the addition of silver nitrate and halide salts to produce an predictable distribution of emulsion crystals containing triangular tabular silver halide grains. It is important to avoid renucleation during the nuclear growth process.

The silver halide nuclei can be formed in a separate vessel and added to the reaction vessel where the growth step is performed. An additional amount of protective colloid and onium compound may be present in the reaction vessel.

To coat the photosensitive photographic layers of the silver halide photographic material at another stage after the precipitation, desalting and redispersion of the silver bromide or silver bromoiodide triangular tabular emulsion, followed by chemical sensitization. To obtain an emulsion that can be made If desired, one or more spectral sensitizers can be added at any stage of the emulsion preparation. More preferably, said spectral sensitizer is added before chemical sensitization.

The photosensitive emulsion containing silver bromide or silver bromoiodide triangular tabular crystals prepared according to the present invention is a so-called basic emulsion after redispersion. Chemical sensitization is described, for example, by P. Glafkides.
Chimie et Physique Photographique, GF Duff
in Photographic Emulsion Chemistry, VL Zel
Making and Coating Photographic Emu by ikman et al.
lsion and Akademische Verlagsgesellschaft 19
Published in 1968, edited by H. Frieser, Die Grundlagen der P
hotographischen Prozesse mit Silberhalogeniden
Can be performed. As described in these documents, chemical sensitization is carried out with compounds containing small amounts of sulfur, selenium and / or tellurium, such as thiosulfates, thiocyanates, the corresponding selenium and / or tellurium compounds, thioureas, sulfites, The ripening can be carried out in the presence of a mercapto compound and rhodanine. Emulsions may also be prepared with gold-sulfur, gold-selenium and / or gold-tellurium ripening agents or with reducing agents,
For example GB-A789823 has such tin compounds as described in, amines, hydrazine derivatives, formamidine - can thus sensitizing the sulfinic acid. Chemical sensitization requires a small amount of I
r, Rh, Ru, Pb, Cd, Hg, Tl, Pd, P
It can also be performed with t or Au. One or a combination of these chemical sensitization methods can be used. Mixtures of two or more separately precipitated emulsions that have been chemically sensitized before mixing can also be made.

According to the present invention, chemical ripening is performed before, during or after spectral sensitization. In conventional emulsion precipitation, spectral sensitization has traditionally been performed after completion of chemical sensitization.
Have gone . However, in the context of tabular grains, it is specifically contemplated that spectral sensitization be performed simultaneously with or completely prior to the chemical sensitization step. It is believed that chemical sensitization after spectral sensitization occurs at one or more ordered and discrete locations on the tabular grains. This can also be done with the emulsions of the invention, in which case the chemical sensitization is carried out with one or more phenidone and derivatives, hydroxybenzenes such as hydroquinone, resorcinol, catechol and / or their derivatives, one or more stabilizers or antifoggants, Performed in the presence of one or more spectral sensitizers or combinations of the above components.

The photosensitive emulsion containing silver halide triangular tabular crystals prepared according to the present invention is described in John Wiley & So
ns Published in 1964, The Cyanin Dyes and Relate
d Compounds can be spectrally sensitized with methine dyes such as those described by FM Hamer. Dyes that can be used for spectral sensitization include cyanine dyes,
Includes merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, hemicyanine dyes, styryl dyes, and hemioxonol dyes. Particularly valuable dyes are those belonging to the cyanine dyes, merocyanine dyes and complex merocyanine dyes. A survey of useful chemical groups of spectral sensitizing dyes and examples that are particularly useful in connection with tabular grains is provided in Research Disclosure Item 22534, supra.

Examples of useful spectral sensitizers include anhydro-5,5'-dichloro-3,3'-bis (n-sulfobutyl) -9-ethyloxacarbo-cyanine hydroxide or anhydro-5,5 '-Dichloro-
There is 3,3'-bis (n-sulfopropyl) -9-ethyloxacarbo-cyanine hydroxide.

Suitable mixtures of spectral sensitizers which can be used include anhydro-5,5'-dichloro-3,3'-bis (n-sulfobutyl) -9-ethyloxacarbocyanine hydroxide or anhydro-5, 5'-dichloro-3,3'-bis (n-sulfopropyl) -9-
Ethyl oxacarbocyanine hydroxide and anhydro-5,5'-dicyano-1,1'-diethyl-
There is 3,3'-di (2-acetoxyethyl) ethyl-imidacarbocyanine bromide. Yet another structural formula is E
This is shown in P-A0677773 . This is incorporated herein by reference.

Other dyes which do not have any spectral sensitizing activity per se, or certain other compounds which do not substantially absorb visible radiation, can be used to enhance the strength when they are incorporated into emulsions with the spectral sensitizers. It can have a color sensitizing effect. Suitable supersensitizers include, for example, US Pat.
Heterocyclic mercapto compounds containing at least one electronegative group as described in US Pat.
A2933390 and nitrogen-containing heterocyclic ring-substituted aminostilbene compounds as described in U.S. Pat. No. 3,635,721, for example, aromatic organic acid-formaldehyde condensation products, cadmium salts, and azaindene compounds as described in U.S. Pat. No. 3,743,510. .

The weight ratio of protective colloid to silver halide, expressed as equivalents of silver nitrate, depends on the precipitation step and / or on the redispersion step or on the subsequent addition of the protective colloid.

The emulsion containing the silver halide triangular tabular grains prepared according to the present invention has a photographic property stable before, during or after chemical ripening or during the manufacture or storage of the photographic material or during photographic processing thereof. Compounds that prevent the formation of fogging or fogging can be added. Mixtures of two or more of these compounds can be added.

Many known compounds can be added to silver halide triangular tabular emulsion crystals as antifoggants or stabilizers. Suitable examples include, for example, heterocyclic nitrogen-containing compounds such as benzothiazolium salts, nitroimidazole, nitrobenzimidazole, chlorobenzimidazole, bromobenzimidazole, mercaptothiazole, mercaptobenzothiazole, mercaptobenzimidazole, mercaptothiadiazole, amino Triazole, benzotriazole (preferably 5-methyl-benzotriazole), nitrobenzotriazole,
47. Mercaptotetrazole, especially 1-phenyl-5-mercaptotetrazole, mercaptopyrimidine, mercaptotriazine, benzothiazoline-2-thione, oxazoline-thione, triazaindene, tetrazaindene and pentazaindene, especially Z. Wiss. Phot. 47 Volumes (1952), pages 2-58, published by Birr, GB-A1203775, GB-A120914.
6, JP-A75-39537 and GB-A15002
Triazolopyrimidines such as those described in US Pat. No. 78, and 7-hydroxy-s-triazolo- [1,5-a] -pyrimidines as described in US Pat.
And other compounds such as benzenethiosulfonic acid, benzenethiosulfinic acid, benzenethiosulfonic acid amide. Other compounds that can be used as antifogging compounds include Research Disclousure No. 17643 (1978).
Year), Ch. VI.

The silver halide emulsions prepared according to the present invention can be used to form photographic silver halide materials by well known methods, to form one or more silver halide emulsion layers coated on a support. Can be used for

Two or more emulsions containing silver halide triangular tabular grains made separately according to the present invention can be mixed into at least one emulsion layer to form a photographic emulsion for use according to the present invention.

The photographic material of the present invention can contain various surfactants in the photographic emulsion layer or at least one other hydrophilic colloid layer. Suitable surfactants include nonionic surfactants such as saponins, alkylene oxides such as polyethylene glycol, polyethylene glycol / polypropylene glycol condensation products, polyethylene glycol alkyl ethers or polyethylene glycol alkyl aryl ethers, polyethylene glycol esters, polyethylene glycol sorbitan esters Polyalkylene glycol alkylamines or alkylamides, silicone-polyethylene oxide adducts, glycidol derivatives, fatty acid esters of polyhydric alcohols and alkyl esters of saccharides; anionic surfactants such as carboxy, sulfo, phospho, sulfate or phosphate groups. Those containing acid groups; amphoteric surfactants such as amino acids, amino acids Alkylsulfonic acids, aminoalkyl sulfates or phosphates, alkyl betaines and amine-N-oxides; and cationic surfactants such as alkylamine salts, aliphatic, aromatic or heterocyclic quaternary ammonium salts, aliphatic or heterocyclic rings Containing phosphonium or sulfonium salts.

Such surfactants may be used for various purposes, for example, as a coating aid, as an antistatic compound, as a compound for improving lubricity, as a compound for facilitating dispersion emulsification, as a compound for preventing or reducing adhesion, And compounds that improve photographic properties, for example, compounds that improve high contrast, sensitization and development acceleration.

The development is promoted by, for example, US Pat.
5, US-A 4038075, US-A 429240
0, EP-A 0634688 and EP-A 067421
Preferably at least 4 such as those described in 5
This can be achieved with the aid of a polyalkylene derivative having a molecular weight of 00.

The photographic material of the present invention may further contain other additives such as a compound for improving the dimensional stability of the photographic material, a UV absorber, a spacing agent, a curing agent, and a plasticizer as described below.

According to the present invention, a silver halide tabular crystal having a support and at least one hydrophilic colloid layer including at least one photosensitive silver halide emulsion layer thereon and having silica as a protective colloid. Is provided, wherein the photosensitive layer contains at least one of the emulsions.

The layers of the photographic material may be of any suitable hardener such as epoxides, ethyleneimines, vinylsulfones such as 1,3-vinyl, especially when the binder used therein is gelatin. Sulfonyl-2-propanol, bis- (vinylsulfonyl) -methane, chromium salts such as chromium acetate and chromium alum, aldehydes such as formaldehyde, glyoxal and glutaraldehyde, N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin, dioxane derivatives such as 2 , 3-Dihydroxydioxane, active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-s-triazine, active halogen compounds such as 2,4-dichloro-6-hydroxy-s-triazine and mucohalic acid In example it can be cured with mucochloric acid and mucophenoxychloric acid. These curing agents can be used alone or in combination. The curing agent is US-P406395
It can be cured with a rapid curing agent such as a carbamoylpyridinium salt as described in No. 2 and with an onium compound as described in EP-A 0 408 143.

The emulsions can be coated on any suitable substrate, preferably a thermoplastic resin such as polyethylene terephthalate, polyethylene naphthalate or a polyethylene coated paper support.

Additives suitable for improving the dimensional stability of the photographic material, such as water-soluble or almost water-insoluble synthetic polymers, such as alkyl (meth) acrylates, alkoxy (meth) acrylates, glycidyl (meth) acrylates, (Meth) acrylamide, vinyl ester, acrylonitrile, polymer of olefin and styrene, or the above and acrylic acid, methacrylic acid, α, β-unsaturated dicarboxylic acid, hydroxyalkyl (meth) acrylate, sulfoalkyl (meth) acrylate And a dispersion of the copolymer with styrene sulfonic acid.

Suitable plasticizers for incorporation in emulsions according to the invention include, for example, glycol, glycerin, polyvinyl acetate, lower alkanol acrylates and methacrylates such as neutral film forming polymers including polyethylene acrylate and polybutylene methacrylate. There is latex.

Suitable UV absorbers include, for example, US-A 35
Aryl-substituted benzotriazole compounds as described in US Pat. No. 33,794, US Pat.
4-thiazolidone compounds as described in A3352681, benzophenone compounds as described in JP-A71-2784, cinnamic acid ester compounds as described in US-A3705805 and US-A3707375, and US-A4045229. Butadiene compounds as described in US Pat.
And benzoxazole compounds as described in

Generally, the average particle size of the spacing agent is 0.2
included in the range of μm to 10 μm Spacing agents can be soluble or insoluble in alkali. Alkali-insoluble spacing agents usually Ri permanently remaining in the photographic element, whereas alkali-soluble spacing agents usually are removed therefrom in an alkaline processing bath. Suitable spacing agents are
It can be made from polymethyl methacrylate, a copolymer of acrylic acid and methyl methacrylate, and a copolymer of hydroxypropyl methylcellulose hexahydrophthalate. Another suitable spacing agent is US-A461.
4708.

Emulsion layers containing silver halide triangular tabular emulsions made according to the present invention, especially thin emulsion layers, show significant improvements in both speed and rapid processing as compared to conventional emulsions.

Photographic silver halide triangular tabular emulsions can be used in various photographic materials, for example, so-called amateur and professional photographic materials, photographic materials for graphic arts,
It can be used in diffusion transfer reversal photographic materials, low speed and high speed photographic materials, X-ray materials, micro photographic materials and the like.

In a preferred embodiment, the photographic silver halide emulsion is used in X-ray materials. In radiography, a material having a single or double emulsion layer coated on one or both sides of the support may contain a silver halide triangular tabular emulsion according to the present invention.

The photographic material may comprise several light-insensitive layers, such as a protective antistress top coat, one or more backing layers, and a filter or halation that eventually absorbs scattered light and thus promotes image sharpness. One or more intermediate layers containing an inhibitor dye can be included. Suitable light-absorbing dyes for use in these intermediate layers are, for example, US-A 4,092,168, US-A4
311787, DE 2453217 and GB-P790
7440. In such interlayers between the emulsion layer and the support, there is preferably only a small negligible loss in speed . However, under rapid processing conditions, decolorization of the filter dye layer can create problems. Therefore, it must be recommended to reduce the overall coating layer packet thickness which results in short drying times after rinsing during the processing cycle. Alternatively, the use of an intermediate layer between the emulsion layer and the support that reflects the fluorescence emitted by the screen can provide a solution.

In color photography, the material contains blue, green, and red sensitive layers, each of which can be single coated, but generally consists of double or triple layers. In addition to the light-sensitive emulsion layer, the photographic material may contain several light-insensitive layers such as protective stress-resistant layers, one or more backing layers, one or more subbing layers, one or more intermediate layers such as filter layers and It may contain an after layer containing a curing agent, an antistatic agent, a filter dye for safety light, and the like.

One or more backing layers can be provided on only one side of the support, on the non-light sensitive side of the support of the material coated with at least one emulsion layer. These layers, which can act as anti-curl layers, can contain matting agents such as silica particles, lubricants, antistatic agents, light absorbing dyes, opacifiers such as titanium dioxide and customary components such as hardeners and wetting agents.

The support of the photographic material can be opaque or transparent, for example a paper support or a resin support. When a paper support is used, an alpha-olefin polymer containing an antihalation dye or pigment, for example one coated on one or both sides with a polyethylene layer, if desired, is preferred. Organic resin supports such as cellulose nitrate film, cellulose acetate film, triacetic acid film,
Poly (vinyl acetal) film, polystyrene film, poly (ethylene terephthalate) film, polycarbonate film, polyvinylidene chloride film,
Alternatively, a poly-α-olefin film such as a polyethylene or polypropylene film can be used. The thickness of such an organic resin film is preferably 0.07 to 0.35 mm.

These organic resin supports are preferably coated with a subbing layer which can contain water-insoluble particles such as silica or titanium dioxide.

The photographic materials containing tabular grains made according to the present invention can be image-wise exposed with any convenient radiation source according to the particular use.

The processing conditions and the composition of the processing solution will of course depend on the particular type of photographic material to which the tabular grains made according to the present invention are applied. For example, in a preferred example of a material for X-ray diagnostic purposes, the material is developed, fixed,
It is preferable to adapt to rapid processing conditions including washing and drying steps. Preferably, an automatic operation processing device provided with a device for automatic regeneration of the processing solution is used. The pre-cured material is
Depending on the processing application that determines the degree of cure required in the processing cycle, the processing can be performed using one packaging chemical or three packaging chemicals. Within the scope of the present invention, Ri may der applied in 30 seconds or less of the total processing time, whereas in normal practice are known applications of 90 seconds or less. From an environmental point of view, it is even possible to use sodium thiosulphate instead of ammonium thiosulphate and to reduce the regeneration of the developer and fixer.

An enhanced rate is obtained for the material coated from the silver halide triangular tabular emulsion according to the invention, especially for short exposures at high radiation intensities, and the growth is increased in the presence of the onium compounds described above. It should be recognized as an exceptional advantage provided by the emulsion crystals directed to the site.

The following examples are illustrative, but not limiting, of the present invention.

EXAMPLES Example 1 For two comparative examples, the following three solutions, whose temperature was kept constant at 55 ° C., were used during the precipitation:

Solution 1: 1.5 l of an aqueous solution containing 500 g of silver nitrate. Solution 2: 0.525 containing 126 g of potassium bromide
l aqueous solution. Solution 3: 0.975 l of an aqueous solution containing 230.4 g of potassium bromide and 0.5 g of potassium iodide.

Emulsion 1 (comparative): At the start, the stirring speed in the vessel was 150 rpm,
UA of -53 mV at 70C against silver / silver chloride reference electrode
The g value was measured. There were 2160 ml of deionized water in the reaction vessel, in which 1.3 g of KBr and 1
2.5 g of inert bone gelatin was placed.

Nucleation step: 35.9 ml of solutions 1 and 2 using the double jet method
Was introduced into the reaction vessel in 28 seconds. One minute after the start of the nucleation step, 520 ml of an aqueous gelatin-containing solution (10%) was added to the reaction vessel.

First growth step: Double jet precipitation was started 10 minutes after using solutions 1 and 2, which lasted 2 minutes 42 seconds. -30 mV during this precipitation
MV value was measured. The flow rates of both solutions were equal to 7.5 ml per minute. After said time, the flow rate is 7.5 m
It was increased linearly from 1 / min to 22.2 ml / min in 31 minutes and 36 seconds. During this time, the same constant mV value was measured. After 5 minutes, the neutralization phase started.

Neutralization step: The solution 1 was flowed at a rate of 7.5 ml / min for 5 minutes and 54 seconds.
A value of +70 mV was measured , after which the second growth step was started.

Second growth step: During 41 minutes and 20 seconds, 7.5 ml of the solution 1 was placed in the reaction vessel.
/ Min to 37.5 ml / min (at the end of the precipitation) at a linearly increasing rate. The mV value was kept constant at +70 mV for the entire time during infusion of solution 3 with solution 1.

Emulsion 2 (comparative): Same as Comparative Emulsion 1, except that the mV value was -61 mV against a silver / silver chloride reference electrode measured at 51 ° C., the temperature at the starting point in the reaction vessel. Followed the law.

Another difference is that the 520 m
l is 21 minutes after the added pressure time <br/> nucleation phase starting amount of the aqueous gelatin-containing solution (10%), after the nucleation step, the temperature of the reaction vessel over a time of 20 minutes, 51 ° C. From 7
It was increased linearly to 0 ℃.

Washing and dispersion method: After the precipitation of the emulsion was completed, the pH was lowered to 3.5 with dilute sulfuric acid, and the emulsion was washed with deionized water at 11 ° C. 45 ° C
Add 160 g of gelatin at 40 ° C. at pH and pAg
Was adjusted to 5.5 and 8.15.

Emulsion 3 (invention): The following solutions were prepared: (1) 0.3 mol of potassium bromide; 150 ml of 15%
Silica sol Kieselsol 500 (trademark of Bayer AG) and 7 ml of co-stabilized phosphonium compound [(Ph
^{_{en) 3 -P + -CH 2 -CH}} 2 OH · Cl -
(Phen represents a phenyl group)] at a temperature of 70 ° C. and a pH of 4.5 containing a 5% solution of (5) a solution of 2.94 mol of silver nitrate. (A); (3) a solution containing potassium bromide at a concentration of 2.94 mol / l (B1); (4) potassium bromide at a concentration of 2.35 mol / l and 0.1 mol / l.
Solution containing potassium iodide at a concentration of 59 mol / l (B2).

Prior to the start of precipitation, the initial UAg measured against a silver / silver chloride reference electrode was adjusted at -34 mV.

The nucleation step was carried out by simultaneously introducing the solution A and the solution B1 into the dispersion medium C at a flow rate of 10 ml / min for 30 seconds. After a physical ripening time of 20 minutes, the pH was adjusted to a value of 3.0 and the solution was stirred for a further 5 minutes.

The growth step then consists of solution A (starting at a flow rate of 2.5 ml / min and increasing the flow rate linearly to a value of 12.5 ml / min at the end) by means of a double jet for 66 minutes. Solution B1 (constant mV value, increasing flow rate to keep -12 mV) was introduced and performed. Meanwhile, the phosphonium compound was injected into the reaction vessel in three stages (26 min 35 sec, 42 min 43 sec and 55 min 19 sec, respectively) during particle growth , and a volume of 8 ml was added during each step.

After cooling the vessel to about 40 ° C., dialysis was performed to obtain a desalted solution having a conductivity of 10 mS or less.

The thus-obtained silver bromoiodide tabular emulsion having 2 mol% of iodide ions exhibited the following grain characteristics.

Emulsion 4 (for reference ): The following solutions were prepared: (1) 0.3 mol of potassium bromide; 150 ml of 15%
And co-stabilizing phosphonium compound of 51.6 mL (trademarked product of Bayer AG) silica sol Kieselsol500 ^{_{[(Phen) 3 -P + -CH 2}} -CH 2 OH · C
l ^- (Phen represents a phenyl group) to make a dispersion medium 3l containing 5% solution of] (C) at a temperature of 70 ° C.,
pH was adjusted to 3.0; (2) 2.94 mol silver nitrate solution (A); (3) solution containing potassium bromide at a concentration of 2.94 mol / l (B1); (4) 2 Potassium bromide and 0.3 mol / l in a concentration of 0.35 mol / l;
Solution containing potassium iodide at 59 mol / l (B2).

Prior to the start of precipitation, the initial UAg measured against a silver / silver chloride reference electrode was adjusted at -34 mV.

The nucleation step was carried out by simultaneously introducing the solution A and the solution B1 into the dispersion medium C at a flow rate of 10 ml / min for 30 seconds. 3.25m after 20 minutes physical aging time
l of a 10% solution of 3-carboxymethylthio-1,2,4-triazole and 20 ml of 10% of imidazole
The solution was added and the pH was adjusted to a value of 3.0. The solution was stirred for another 5 minutes.

Next, the growth process is performed by using a double jet for 66 hours.
In minutes, solution A (starting at a flow rate of 2.5 ml / min and increasing the flow rate linearly to a value of 12.5 ml / min at the end) and solution B1 (to maintain a constant UAg value of +5 mV)
At increasing flow rates).

After cooling the vessel to about 40 ° C., 125 g of 20
% Aqueous gelatinous solution was added and the emulsion was stirred for 5 minutes.
H was adjusted to a value of 3.0 and polystyrene sulfonic acid was added in an amount to cause aggregation. The coagulate was washed three times with 2 liters of deionized water to obtain a desalted emulsion.

Emulsion 5 ( Reference ): The following solutions were made: (1) 0.131 mol of potassium bromide;
% Silica sol Kieselsol 500 and co-stabilizing phosphonium compound of 5% solution of 20 ml (trademarked product of Bayer AG) ^{_{[(Phen) 3 -P + -CH 2}} -CH 2 O
H.Cl ⁻ (Phen represents a phenyl group)] was prepared at 70 ° C. and the pH was adjusted to 3.0; (2) a 2.94 mol silver nitrate solution (A); (3) a solution containing potassium bromide at a concentration of 2.94 mol / l (B1); (4) potassium bromide at a concentration of 2.35 mol / l and 0.1 mol / l.
A solution containing potassium iodide at a concentration of 59 mol / l (B
2).

An initial UAg value of -15 mV was measured against a silver / silver chloride reference electrode , said UAg value being +200 mV before the start of precipitation with a silver nitrate solution (0.294 mol).
Was adjusted.

The nucleation step was carried out by simultaneously introducing the solution A and the solution B1 into the dispersion medium C at a flow rate of 10 ml / min for 30 seconds. After 20 minutes physical aging time, 120m
1 Kieselsol 500 in silica sol (15%) and 80 ml of the same co-stabilized phosphonium compound
The pH was adjusted to a value of 3.0 by addition with 0 ml of deionized water. The solution was stirred for another 5 minutes.

Next, the growth step is started at a flow rate of 2.5 ml / min by a double jet at 2 minutes and 38 seconds, and then at a flow rate of 2.5 ml / min to a final value of 7.5 ml / min during 32 minutes and 30 seconds. Was increased linearly. Solution B1 is +8 mV
Was added with solution A at increasing flow rates to maintain a constant UAg value of

After the growth step, a physical ripening time of 5 minutes and 30 seconds was maintained before starting the second growth step. 5 minutes 54 seconds,
Solutions A and B2 were introduced into the reaction vessel: Solution A was 2.5
At a constant flow rate of ml / min, solution B2 has a UA of +8 mV.
It was added at a flow rate to keep the g value constant. Then 41 minutes 2
In 2 seconds, the flow rate of solution A increases to 12.5 ml / min,
The UAg value was kept at +8 mV.

After cooling the vessel to about 40 ° C., 125 g of 20
% Aqueous gelatinous solution was added and the emulsion was stirred for 5 minutes.
H was adjusted to a value of 3.3 and polystyrene sulfonic acid was added in an amount that caused aggregation. To obtain a desalted emulsion,
The aggregate was washed twice with 2 l of deionized water.

The average diameter d _EM , the average thickness t, and the average aspect ratio AR were obtained from electron micrographs: the diameter of the grains is the diameter of a circle having an area equal to the projected area of the grains when viewed in said pictures. Defined as The mean sphere equivalent diameter d _M in the table was calculated from the values of d _EM and t by the following equation.

D _M = (3/2 × d _EM ² × t) ^1/3

From the data obtained for 1000 particles, the standard deviation ν was calculated stochastically, and the values of the coefficient of variation defining the quotient of the standard deviation and the average diameter were tabulated.

Further analyzes of triangular and hexahedral crystals are shown in Tables 1 and 2, and a comparison between the ratios of both different forms of crystals is shown in Table 3.

[0110]

[Table 1]

[0111]

[Table 2]

[0112]

[Table 3]

[0113]

[0114]

[0115]

In summary, a similar growth mechanism is observed for crystals made by the method of the present invention. A completely different phenomenon is observed for the comparative emulsion, which is an indicator for the different growth mechanisms of the triangular and hexahedral in that case.

[0117]

During redispersion of the emulsion, an amount such that the weight ratio of gelatin to silver halide (expressed as silver nitrate) becomes 0.25 and the emulsion contains an amount of silver bromoiodide equal to 190 g of silver nitrate per kg. Of inert gelatin was added.

The emulsion is chemically ripened with sulfur and gold at 47 ° C. for 4 hours and coated on one side of a 175 μm thick polyester support to obtain the best relationship between fog and sensitivity. Before, 4-hydroxy-6-methyl-1,
Stabilized with 3,3a-tetraazaindene. Therefore, an optimal amount of toluenethiosulfonic acid is used as a preripening agent that weakly oxidizes before chemical ripening, followed by silver bromoiodide 1
Per mole, 362.5 mg as spectral sensitizer
Of anhydro-5,5'-dichloro-3,3'-bis (n-sulfobutyl) -9-ethyloxacarbo-cyanine hydroxide. An additional 200 mg of 1-p-carboxyphenyl-5-mercaptotetrazole was added.

The emulsion layer was overcoated with a protective layer. The amounts of coating solution were all the same in the protective layer as well as in the emulsion layer.

Before coating, the following components were added per mole of silver halide: 78 as antifoggant and stabilizer
5 mg of 4-hydroxy-6-methyl-1,3,3a,
7-tetraazaindene, 39 mg as a curing accelerator
Phloroglucin, 2.68 g of resorcinol as a curing agent.

Deionized water was added in order to reach a concentration corresponding to about 200 g of silver nitrate per liter of coating solution.

A protective coating composition was prepared containing the following components in deionized water for 1 l: 35.4 g of inert gelatin, 37 g of silica sol with silica particles having an average diameter of 7 to 10 nm, 3.2% 20 g, 225 mg of an aqueous dispersion of a matting agent having a particle diameter of 2 .mu.m containing polymethyl methacrylate and 10% of gelatin
Chromium acetate as a curing agent, 30 as a surfactant
0 mg of ammonium perfluorooctanoate (F
C143, product name from 3M) and 750 mg of N
Polyoxyethylene-N-ethyl-perfluorooctane-sulfonamide (FC170C, trade name product from 3M), 1500 mg of phenol as preservative,
1000 mg of Mobilcer Q (MOBIL OI
L). Formaldehyde was added as a hardener.

[0124] For all of the emulsion, the ratio of gelatin to silver nitrate was about 0.3.

Due to the large amount of curing agent, it should be added to the protective topcoat composition just prior to coating so as to have relatively water absorption.

The opposite side was coated with a conventional antihalation backing layer.

After coating and drying, the coating material was exposed to 540 nm green light for 0.1 second using a continuous optical wedge, using the following time (second) and temperature (° C.) characteristics to treat the processor CURI.
Treated with XHT530 (trade name of Agfa-Gevaert) for a 38 second processing cycle:

Charge: 0.2 seconds Development: 9.3 seconds, crossover at 35 ° C. in the following developer: 1.4 seconds Rinsing: 0.9 seconds Crossover: 1.5 seconds Fixing: 6.6 Second, in the following fixer at 35 ° C. Crossover: 2.0 seconds Washing: 4.4 seconds, 20 ° C. Crossover: 4.6 seconds Drying: 6.7 seconds Total 37.6 seconds

Composition of developer: Concentrated part: Water 200 ml Potassium bromide 12 g Potassium sulfite (65% solution) 249 g Sodium ethylenediaminetetraacetate trihydrate 9.6 g Hydroquinone 106 g 5-methylbenzotriazole 0.076 g 1-phenyl- 5-mercaptotetrazole 0.040 g sodium tetraborate (decahydrate) 70 g potassium carbonate 38 g potassium hydroxide 49 g diethylene glycol 111 g potassium iodide 0.022 g 4-hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidinone 22 g with water Make it 1 l.

The pH was 11.1 at 25 ° C. with potassium hydroxide.
Adjusted to 5. To start the process, a part of the concentrated developer was mixed with 3 parts of water. No initiator was added. The pH of this mixture was 10.30 at 25 ° C.

Composition of Fixer: Concentrated part: ammonium thiosulfate (78% solution) 661 g sodium sulfite 54 g boric acid 25 g sodium acetate trihydrate 70 g acetic acid 40 g Make up to 1 l with water.

The pH was adjusted to 5.30 at 25 ° C. with acetic acid.

In order to use this fixer immediately, 1 part of the concentrated portion was mixed with 4 parts of water. A pH of 5.25 was measured at 25 ° C.

Table 4 shows the sensitivity data obtained after processing the materials containing emulsion Nos. 1, 4 and 5, respectively, after exposure with an exposure time of 10 ^-2 and 10 ^-6 seconds, respectively. The product of exposure time and radiation intensity was kept constant.

The sensitivity S was measured at the density of the support and the density of 1 above fog.

Since the amount of light required to reach a support density and a density of 1.00 above fog is smaller for larger photosensitive materials, the lower the sensitivity, the greater the sensitivity. 10
As shown in Table 2 at 0 times log exposure,
Each time it is reduced by a value of 0, it is an indication of a material having twice the sensitivity.

The amount of coated silver (AGC) given as equivalents of silver nitrate for 1 m ² is additionally indicated.

[0138]

[Table 4]

The fact that the difference in sensitivity between flash exposure and long exposure is small for triangular emulsion crystals made by the method according to the invention is due to the reduced dispersion of the latent image centers for said triangular crystals. Can be understood.

Example 2 Emulsion 6 (Invention): The following solution was prepared: (1) 0.13 mol of potassium bromide, 15% silica sol
Kieselsol 500 (trademark product of Bayer AG) 50 m
l, and a co-stabilized phosphonium compound [(Phen) _{3
^{-P + -CH 2 -CH 2 OH ·}} Cl - (Phen
Represents a phenyl group), 2.5 l of a dispersing medium (C) containing 15 ml of a 5% solution of 5% at 70 ° C. and adjusting the pH to 3.0; (2) a 2.94 mol silver nitrate solution ( (A); (3) a solution containing potassium bromide at a concentration of 2.94 mol / l (B1); (4) potassium bromide at a concentration of 2.49 mol / l and 0.1 mol / l.
A solution containing potassium iodide at a concentration of 45 mol / l (B
2).

Prior to the start of precipitation, the initial UAg measured against a silver / silver chloride reference electrode was adjusted to -34 mV.

The nucleation step was carried out by simultaneously introducing the solution A and the solution B1 into the dispersion medium C at a flow rate of 60 ml / min for 30 seconds. After 20 minutes physical ripening time, Kieselsol
100 ml of a 15% solution of 500 and 30 ml of a 5% solution of the same phosphonium compound were added together with 320 ml of deionized water and the pH was adjusted to a value of 3.0. The solution was stirred for another 5 minutes.

Next, the growth process was carried out with a double jet for 31 minutes and 4 minutes.
At 8 seconds, solution A, starting at a flow rate of 2.5 ml / min and increasing the flow rate linearly to a final value of 7 ml / min, and +1
Solution B at increasing flow rate to maintain a constant UAg value of 0 mV
1 was introduced.

After a physical ripening time of 5 minutes and 30 seconds, a second growth step was performed.

This second growth step was started with a double jet at a flow rate of 2.5 ml / min for 5 min 54 sec and then increased linearly to a final value of 12.5 ml / min in 41 min 22 sec. The solution B2 was added by +10
Introduced at increasing flow rates to maintain a constant UAg value of mV.

After the container was cooled to about 40 ° C., 125 g of a 20% aqueous gelatinous solution was added, and the emulsion was stirred for 5 minutes.
Was adjusted to a value of 3.0 and polystyrene sulfonic acid was added in an amount that caused aggregation. The aggregates were washed twice with 4 l of deionized water to obtain a desalted emulsion.

Emulsion 7 (invention): 67 ml of 15% silica sol Kieselsol 500 (Bay)
er AG) and 40 ml of a 5% solution of a co-stabilized phosphonium compound are present in 2.5 l of dispersion medium (C) and after a first physical ripening time of 20 minutes following the nucleation step, the Kieselsol 500 237 ml of a 15% solution and 80 ml of a 5% solution of the same phosphonium compound
The pH of the emulsion was adjusted to a value of 3.0 by adding the same preparation as Emulsion 6, except that it was added together with deionized water.

Emulsion 8 (invention): 33 ml of 15% silica sol Kieselsol 500 (Bay)
er AG) and 15 ml of a 5% solution of a co-stabilized phosphonium compound are present in 2.5 l of dispersion medium (C) and after a first physical ripening time of 20 minutes following the nucleation step, 67 ml of 15% solution of Kieselsol 500 and 30
353 ml of 5% solution of the same phosphonium compound
The same preparation as Emulsion 6 was added except that it was added with deionized water to adjust the pH to a value of 3.0.

Separate analysis of triangular and hexahedral crystals
A comparison between the ratios of both separate forms of the crystals, shown in Tables 5 and 6, exactly as in Tables 1 and 2, is shown in Table 7, as in Table 3.

[0150]

[Table 5]

[0151]

[Table 6]

[0152]

[Table 7]

COSI: weight ratio of phosphonium co-stabilizer to silica: SISI: weight ratio of silica to silver ^* . *: The amount of silver is given as the equivalent of silver nitrate.

The following conclusions can be drawn from Tables 5, 6 and 7.

For emulsions made according to the present invention that differ in COSI and SISI, the grain size is comparable.

For the emulsion prepared by the method of the present invention,
The value of the ratio of d _EM is around a value of about 0.8, which is in the range for the emulsion from Example 1 and the ratio of the thickness of triangular to hexahedral tabular crystals is 1 unit. .3 ~
0.7.

Similarly, AR for triangular and hexahedral crystals
The value ratio is about 0.8 for crystals made according to the invention.
Yields the value of This is again an indication of the comparable thickness of triangular and hexahedral crystals present in emulsions made by the method of the present invention. COS as well as for emulsions 6-9
It can be said that there is no significant difference for emulsions made within I and SISI ranges.

In summary, the same growth mechanism for crystals made by the method of the present invention as described above for COSI and S
Observed within ISI.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Peter Welp Septestart, Mortseell, Belgium 27 Inside Agfa Geverth na Mroseze Bennacht Chap (56) References JP-A-3-238443 (JP, A) JP-A-7-20601 (JP, A) JP-A-6-180488 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03C 1/035 G03C 1/015 G03C 1/07

Claims (5)

(57) [Claims] A photosensitive silver bromide or silver bromoiodide emulsion containing silver bromide or silver bromoiodide triangular tabular grains and hexahedral tabular grains, wherein said triangular tabular grains are less than 0.3 μm. Having an average grain thickness of at least 0.6 μm, an average diameter of a circle having the same area of at least 0.6 μm, an average aspect ratio of at least 2: 1 and a coefficient of variation of less than 40%, wherein the triangular tabular grains have a In a photosensitive silver bromide or silver bromoiodide emulsion that is at least 30%
Is from 25% to 55% of the total number of grains , and the ratio of the thickness of triangular tabular grains to hexahedral tabular grains (t _tr /
(t _hex ) is 1.3 to 0.7. A light-sensitive silver bromide or silver bromoiodide emulsion. 2. The thickness ratio (t _tr / t _hex ) of triangular tabular grains to hexahedral tabular grains is from 13/12 to 11 /.
13. The photosensitive silver bromide or silver bromoiodide emulsion according to claim 1, wherein 3. A light-sensitive silver halide photographic material having at least one hydrophilic colloid layer containing at least one light-sensitive layer on at least one side of a support, wherein the light-sensitive layer is one of the light-sensitive layers. 2. A light-sensitive silver halide photographic material, which is coated from at least one silver bromide or silver bromoiodide emulsion. 4. precipitating silver bromide or silver bromoiodide by a double or triple jet method applied to an aqueous solution of silver nitrate and a halide salt in the presence of a protective colloid, wherein 9.5, A constant pAg value in the range 〜8.0,
Controlling the nucleation and growth steps by a variable flow rate of an aqueous solution of silver nitrate and halide salts, at least one physical ripening step between at least the nucleation step and the first growth step, desalting the reaction medium, 4. A method for producing a photosensitive silver bromide or silver bromoiodide emulsion according to claim 1, further comprising the step of redispersing silver halide and chemically ripening silver halide grains. Method. 5. Use of gelatin and / or colloidal silica as a protective colloid in the presence of an onium compound,
The method of claim 4 wherein the weight ratio of said onium compound to said protective colloid is from 0.03 to 0.50 when silica is present.