JPH051927B2 - - Google Patents

Description

[Detailed description of the invention]

(A) Industrial Application Field The present invention relates to silver halide photographic emulsions, and particularly to silver halide photographic emulsions having improved sensitivity, gradation, fog, and density. (B) Prior art and its problems There have been many methods to increase the sensitivity of silver halide photographic emulsions, such as gold, platinum,
Noble metal sensitization using compounds of noble metals such as iridium, sulfur sensitization using sulfur-containing compounds such as thiourea and hypo, reduction sensitization using monovalent tin salts, polyamines, hydrazine derivatives, etc., or quaternary ammonium salts, Methods such as development acceleration using polyalkylene glycol and the like are known. Silver halide photographic emulsions with higher sensitivity can also be obtained by applying the above sensitization method to emulsions made of silver halide containing silver bromide as a main component, especially silver halide with increased grain size. well known. However, large grain silver halide photographic emulsions mainly composed of silver bromide as described above generally have the disadvantage of being soft in tone and having a low maximum density. In addition, conventional attempts to increase contrast, such as the use of well-known rhodium salts, are accompanied by desensitization, and silver halide photographic emulsions containing silver bromide as a main component cannot be said to have sufficient contrast. Even if stronger chemical sensitization is applied to compensate for this desensitization, fogging still occurs, so there is naturally a limit to the sensitivity that can be obtained. Furthermore, one method for obtaining a high maximum density with a fixed amount of silver halide is to use fine grain silver halide, but this method also results in a decrease in sensitivity. (C) Object of the invention The object of the invention is to improve gradation (high contrast),
density (high maximum density), fog (reduced fog)
It is an object of the present invention to provide a silver halide photographic emulsion containing silver bromide as a main component and having sensitivity (sensitization). Other objects of the invention will be apparent from the following description. (D) Structure of the Invention The object of the present invention is to contain at least one compound represented by the following general formula (A) or its oxidized product and at least one compound represented by the following general formula (B). This was achieved using a silver halide photographic emulsion mainly composed of silver bromide, which has a characteristic average grain size of 0.5 μm or more. General formula (A) (In the formula, Z represents an aromatic group) General formula (B) (In the formula, A is a hydroxyl group, an amino group, , R ₁ and R ₂ form a ring together with the C atom to which they are bonded, or one is a hydrogen atom and the other is a hydrogen atom, an alkyl group, an aryl group, or a hydroxyl group, and n is 0 or 1 to The integer of 8 and M represent a hydrogen atom or an alkali metal. ) Representative examples of the compound represented by the general formula (A) used in the present invention are shown below.

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[Formula] Representative examples of the compound represented by the general formula (B) used in the present invention are shown below. (B-1) HO−CH ₂ −SO ₃ Na (B-4) HO−(CH ₂ ) ₂ −SO ₃ K (B-6) HO-( _CH2 ) _{6 - SO3NH4} (B-12) _H2N - _CH2 - _SO3Na The compound of general formula (A) is generally used as a developing agent in silver halide photographic materials for black and white, and is also known to be included in the emulsion layer thereof (for example, in JP-A No. 47-832, 1972-
11029, Showa 58-95729, etc.). It is added to the silver halide photographic emulsion at any time after desalting, usually after chemical ripening. The amount added is 0.01 to 0.5 mol per mol of silver halide, preferably
It ranges from 0.05 to 0.3 mol. The compound of general formula (B) may be incorporated into the paper of a polyethylene resin-coated paper support to prevent discoloration of the developing agent (for example, as disclosed in JP-A No. 47-832 and JP-A No. 58-832).
95729, etc.), it is known to improve the storage stability of the emulsion by incorporating it into the silver halide emulsion layer (for example, JP-A-163935-1989). The compound of general formula (B) is added to the silver halide photographic emulsion at any time after desalting, generally after chemical ripening.
The amount to be added is 0.001 to 1 mole of silver halide.
0.5 mol, preferably in the range of 0.003 to 0.3 mol. The silver halide photographic emulsion of the present invention is mainly composed of silver bromide, that is, it contains silver bromide in an amount of 50 mol% or more, and preferably silver bromide is contained in an amount of 80 to 100 mol%.
It consists of silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide, which can contain up to 5 mol % of silver iodide. These silver halides have an average grain size of at least 0.5 μm. Preferably
It is 0.55μm or more. The silver halide may have any shape, and any known method for producing it may be used. For example, precipitation may be performed by any method such as an ammonia method, a neutral method, an acid method, or a partial ammonia method that is a combination of a neutral method and an ammonia method.
Further, any mixing method such as forward mixing, back mixing, or simultaneous mixing may be used, and in particular, a simultaneous mixing method called the so-called double jet method in which crystal habit is controlled under the control of PAg can also be applied. Furthermore, it can also be applied to conversion methods that utilize differences in solubility. For example, the conversion method type emulsion preparation method is described in U.S. Patent No.
Described in No. 2592250. Furthermore, J. photo.
Also included are emulsions precipitated in the presence of crystal habit modifiers, such as those described in Sci., 21 39-50 (1973). Metals such as rhodium and iridium can also be used during precipitation or physical ripening of silver halide. These emulsions can be subjected to chemical ripening by known methods. Namely, U.S. Patent No. 1574944,
No. 2278947, No. 2410689, No. 3189458, No.
Sulfur sensitization can be performed using a sulfur compound or a sensitized gelatin containing a sulfur compound as described in No. 3501313 and the like. Also, U.S. Patent No. 2597856,
Gold sensitization using gold compounds described in 2597915, 2399083, etc. can also be performed. Salts of noble metals such as platinum, palladium, rhodium, iridium, ruthenium, etc. can also be added, as described in US Pat. Also, U.S. Patent No.
No. 2518698, No. 2521925, No. 2487850, No. 2518698, No. 2521925, No. 2487850, No.
Reduction sensitization can also be performed as described in No. 2694637. These sensitization methods can be used not only alone but also in combination. The photographic emulsion used in the present invention can also be sensitized using quaternary ammonium salts, thioether compounds, polyethylene oxide derivatives, diketones, and the like. These methods are covered by U.S. Patent No.
No. 2708162, No. 3046132, No. 3046133, No.
It is described in No. 3046134, No. 3046135, British Patent No. 939357, etc. As binders or protective colloid substances for the photographic emulsion used in the present invention, lime-treated or acid-treated gelatin, gelatin derivatives such as phthalated gelatin, and polyvinyl alcohol are mainly used.
Furthermore, polysaccharides such as polyvinylpyrrolidone, acrylic water-soluble copolymer, starch and its derivatives, and cellulose derivatives can be used in combination. It is also possible to modify the physical properties of the gelatin film by adding latex polymers, or to make the film surface matte by adding starch powder, colloidal silica, glass powder, etc. A known hardening agent may be added to the photographic emulsion of the present invention. Examples of hardening agents include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and cyclopentanediol, and bis(2chloroethylurea)-2-hydroxy-4,6-dichloro-
1,3,5-triazines, compounds with reactive halogens as described in U.S. Pat. No. 3,288,775;
divinyl sulfone, compounds with reactive olefins as described in U.S. Pat. No. 3,635,718, N-methylol compounds as described in U.S. Pat. No. 2,732,316;
Isocyanates as described in US Pat. No. 3,103,437, aziridine compounds as described in US Pat. No. 3,017,280 and US Pat. No. 2,983,611, carbodiimide compounds as described in US Pat. compounds, halogen carboxaldehydes such as mucochloric acid,
Examples include dioxane derivatives such as dihydroxydioxane, inorganic hardeners such as chromium alum, and any combination of these may be used freely. The photographic emulsion of the present invention may contain a coating aid, that is, a surfactant for lowering the surface tension and improving the wetting effect. In addition to saponin, effective coating aids include nonionic surfactants such as alkylene oxides, glycerin, and glycidol, higher alkylamines, quaternary ammonium salts, pyridine and other heterocycles, and cationic surfactants such as sulfoniums. anionic surfactants containing acidic groups such as carboxylic acid, sulfonic acid, phosphoric acid, sulfuric acid ester groups, and phosphoric acid ester groups;
Examples include amphoteric surfactants such as amino acids, aminosulfonic acids, and amino alcohol esters;
No. 3589906, West German Patent Publication No. 1961638, West German Patent Application No. 2124262
Also included are fluorinated surfactants described in the above. The photographic emulsion of the present invention may further contain a developing agent such as 1-phenyl-pyrazolidones or metols in addition to the compound of general formula (A). The photographic emulsion of the present invention can be optically sensitized with a sensitizing dye such as cyanine or merocyanine. The support to which the emulsion according to the present invention is coated is not particularly limited. That is, it can be applied to a film base such as polyester film or cellulose triacetate film, a paper base such as baryta paper, resin-treated paper, or plywood paper, or a support such as dry plate glass or metal plate. A subbing layer, intermediate layer, protective layer, backing layer, etc. may also be provided. (E) Examples Examples will be described below to further specifically explain the present invention, but the present invention is of course not limited thereto. Example 1 Gelatin 60g Salt 12g Water 400ml Silver nitrate 120g Water 1000ml Potassium bromide 85g Potassium iodide 1.2g 28% aqueous ammonia 100ml Water 900ml Acetic acid Keep the solution at 50°C, add the solution with strong stirring, and add the solution after 1 minute. After ripening at 50° C. for 60 minutes, the solution was added to adjust the pH to 3 to obtain a silver iodobromide emulsion with an average grain size of 0.62 μm. After desalting and washing with water, this emulsion was redissolved and gelatin was added to adjust the pH to 6.0, and then 20 mg of sodium thiosulfate per mol of silver halide and 10 mg of chloroauric acid per mol of silver halide were added to the emulsion. , at 60℃
Chemically aged for 60 minutes. 4 after adjusting PH to 5.5
Compound (A-1) and compound (B-1) were added per mole of silver halide as shown in Table 2 below, and a hardener and a surfactant were added. A multilayer coating was applied on a polyethylene resin paper support together with a gelatin protective layer so that the amount of silver was 2.2 g/m ² . Each sample prepared in this way was cut into appropriate sizes, exposed to flash light for 10 ^-5 seconds through a wedge with a density difference of 0.15, and then developed. Development was carried out at 25° C. for 1 minute using a developer with the following composition. Water (approximately 30°C) 500ml Metol 3.1g Hydroquinone 12g Anhydrous sodium sulfite 45g Anhydrous sodium carbonate 67.5g Potassium bromide 1.9g Water was added to give 3000ml After this, it was stopped, fixed, washed with water, and dried. Table 3 shows the results of measuring photographic properties.

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[Table] Relative sensitivity is density 0.3 and 1.0 (excluding fog value)
(S0.3 and
S1.0) and Sample 1 are each expressed as relative sensitivity when taken as 100. From the results in Table 3, for sample 4 containing compounds (A-1) and (B-1), the sensitivity in the high concentration area (S1.0) is higher than the sensitivity in the low concentration area (S0.3). It can be seen that the image is significantly sensitized, resulting in higher contrast (γ), higher maximum density (Dmax), and less fog. Comparative Example 1 A test was carried out in the same manner as in Example 1, except that the emulsion formulation of Example 1 was ripened at a temperature of 40° C. for 6 minutes to obtain a silver iodobromide emulsion with an average grain size of 0.4 μm. Samples 1R to 4R were used corresponding to samples 1 to 4, and the results are shown in Table 4.

Table 4 shows that the effect of Example 1 is substantially absent. Example 2 A silver chlorobromide emulsion containing 5 mol % of silver chloride was prepared by an ammonia method. 2×10 ⁻⁷ mol of rhodium trichloride was used per mol of silver halide during precipitation. The average grain size of the silver halide was 0.75 μm. After desalting and washing with water, chemical ripening was carried out in the same manner as in Example 1. After finishing, stabilizers, sensitizing dyes, hardeners, and surfactants were added and divided into 8 equal parts, and the general formula (A) and the general formula A coating liquid was prepared by adding the compound of formula (B) as shown in Table 5 below.

[Table] These emulsions were coated and dried in the same manner as in Example 1, then exposed and developed. The results are shown in Table 6.

[Table] Results similar to those in Example 1 were obtained. (F) Effects of the Invention According to the present invention, a silver halide photographic emulsion having photographic properties of higher sensitivity, higher contrast, higher maximum density, and lower fog can be obtained.

Claims (1)

[Scope of Claims] 1. A silver halide photographic emulsion mainly composed of silver bromide with an average grain size of 0.5 μm or more, which has the following general formula:
A silver halide photographic emulsion comprising at least one compound represented by (A) or its oxidized product and at least one compound represented by the following general formula (B). General formula (A) (In formula (A), Z represents an aromatic group.) General formula (B) (In formula (B), A represents a hydroxyl group or an amino group, R ₁ and R ₂ form a ring together with the bonded C atom, or one is a hydrogen atom and the other is a hydrogen atom or an alkyl group, represents an aryl group or a hydroxyl group, n is 0 or an integer of 1 to 8, and M represents a hydrogen atom or an alkali metal.)