JPH0222935B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a silver halide photographic material, and more particularly to a silver halide photographic emulsion suitable for a light-sensitive material for bright room use. In recent years, in the printing field, the complexity of printed matter,
With the development of scanners, there has been a demand for improved efficiency in the turning process. Therefore, compared to the conventionally used return film, it is 10 ^-3 ~
A photographic film with an ultra-low sensitivity of about 10 ^-5 was developed,
It has begun to be put into practical use as a return film that can be handled in a bright room (under a white fluorescent light without ultraviolet rays), that is, as a photosensitive material for bright rooms. The performance required of such light-sensitive materials for use in bright rooms is that they have high contrast and sufficient maximum density, can be handled for long periods of time in bright rooms, and have high sensitivity to ultraviolet light. This is the case. However, it cannot be said that conventional photosensitive materials for use in bright rooms fully satisfy the above-mentioned performance, and there is a desire to develop improved photosensitive materials for use in bright rooms. As a silver halide emulsion for light-sensitive materials for bright room use, a large amount of rhodium as an inorganic desensitizer is used in silver halide mainly composed of silver chloride as described in JP-A-56-125734. or a method using an organic desensitizer such as pinacryptol yellow, which is commonly used in positive silver halide emulsions. However, the present inventors have found that emulsions produced by either of the above methods have a serious drawback in that they can only guarantee insufficient safety when handled as light-sensitive materials under bright white light. I confirmed that there is. Emulsions using rhodium salts cause significant fogging under bright room light. Emulsions using organic desensitizers can be handled under bright room light for long periods of time without causing fogging like rhodium salts do, but after image exposure and before development, Even if it was left under room light for a short time, a significant decrease in sensitivity occurred. Of course, it is sufficient to develop the image immediately after exposure, but for reasons such as staleness, it is sometimes left under bright room light after image exposure, and it is desired that handling safety in this case be improved. has been done. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a silver halide emulsion for bright-room light-sensitive materials, which improves the above-mentioned drawbacks that occur when an organic desensitizer is used. Other objects of the invention will be apparent from the following description. As a result of extensive research to achieve the above object, the present inventors have discovered that a negative-working fine-grain silver halide emulsion containing at least 80% silver chloride contains at least one organic desensitizer and at least 2-mercaptobenzoic acids. It has been found that the above object can be achieved by a silver halide emulsion characterized in that it contains seeds and contains an anionic surfactant. In addition to thiosalicylic acid, the 2-mercaptobenzoic acids used in the present invention include those in which thiosalicylic acid is substituted with an alkyl group, an alkoxy group, an amino group, an acylamino group, a halogen atom, etc., and 2-mercaptobenzoic acids that form a mercapto group. Those with protective groups such as S-acetylthiosalicylic acid, S-methylcarbamoylthiosalicylic acid,
S-phenylcarbamoylthiosalicylic acid, S-
Examples include ethoxycarbonylthiosalicylic acid. These thiosalicylic acids are described, for example, in JP-A-56
It is publicly known from, for example, Publication No.-8145. These thiosalicylic acids are preferably added to the silver halide emulsion, but they may also be added to the layer coating adjacent to the emulsion layer and diffused into the emulsion layer. It can be added at any time during the emulsion manufacturing process, and the amount added is generally about 20 mg per mole of silver halide.
It can be appropriately selected within the range of ~5g. Of course, other antifoggants or stabilizers can also be used if necessary. The organic desensitizer used in the present invention is generally known to be used in direct positive silver halide emulsions. That is, the organic desensitizer used in the present invention is characterized by its polarographic half-wave potential, that is, its oxidation potential determined by polarography. Organic desensitizers useful in the present invention are those in which the sum of polarographic anode potential and polarographic cathode potential is positive. For information on how to measure these redox potentials,
For example, as described in US Pat. No. 3,501,307. Specific examples of such organic desensitizers are described in numerous patent specifications, all of which have the same effect in the present invention. Showa 39-
20261, 1973-26751, 13167-13167, 1972
-8833, 1974-8746, 1977-10197, 1972
-37530, JP-A-48-24734, JP-A-49-84639, JP-A-56-142525, U.S. Patent No. 2271229, No.
Compounds described in specifications such as No. 2541472, No. 3035917, No. 3062651, No. 3124458, No. 3326687, and No. 3671254 can be used. An example is shown below. (D-1) 1,3-diethyl-1'-methyl-
2'-phenylimidazo[4,5-b)-
Quinoxalino-3'-indolocarbocyanine iodide (D-2) Pinacriptol Yellow (D-3) 1,1'3,3,3',3'-hexamethyl-5,5'-dinitroindocarbocyanine P-Toluenesulfonate (D-4) 5,5-dichloro-3,3'-diethyl-6,6'-dinitrothiacarbocyanine iodide (D-5) 1,1'-dimethyl-2,2 '-Diphenyl-3,3'-indolocarbocyanine bromide (D-6) 1,1'-3,3'-tetraethylimidazo[4,5-b]quinoxalinocarbocyanine chloride (D-7 ) 5-m-nitrobenzylidenerhodanine (D-8) 6-chloro-4-nitro-nitrobenzotriazole (D-9) 1,1'-dibutyl-4,4'-bipyridinium dibromide (D-10 ) 1,1'-ethylene-2,2'-bipyridinium dibromide (D-11) 4-(P-n-amyloxyphenyl)
-2,6-di(P-ethylphenyl)thiavirylium perchlorate (D-12) 2-mercapto-4-methyl-5-
Nitrothiazole (D-13) 2-(O-nitrostyryl)-3-ethylbenzothiazolylium P-toluenesulfonate (D-14) 2-(P-nitrostyryl)-quinoline P-toluenesulfonate (D -15) Phenosafranine (D-16) Pinacrypt Green (D-17) 2,3-dimethyl-6-nitro-benzothiazolium P-toluenesulfonate The amount of organic desensitizer used is The amount is selected in the range of 50 mg to 5 g, preferably 100 mg to 3 g per mole of silveride. The timing of addition is not limited, although it is generally added after the completion of ripening. Surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants, but anionic surfactants are particularly suitable for light-sensitive materials used in bright rooms. Anionic surfactants are further classified into the following groups: 1) Carboxylic acids and their salts (e.g. Aerol OP manufactured by Toho Chemical Co., Ltd.) 2) Sulfonic acids and their salts (e.g. Neogen manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 3) Sulfuric acid and sulfite ester salts (e.g. Monogen manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 4) Phosphoric acid esters and their salts (e.g. Enolene manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 5) Phosphorous acid and phosphonate esters (e.g. Asahi Oil & Fats) Eletol OP) 6) Thiophosphoric acid type 7) Boron-containing type 8)
Polymerized polymer systems (for example, Vinylite MAC manufactured by Kyoeisha Yushi Co., Ltd.) 9) Polycondensed polymer systems (for example, Demol manufactured by Kao Soap Co., Ltd.). Although all of these anionic surfactants are more useful for light-sensitive materials than nonionic surfactants, cationic surfactants, and amphoteric surfactants, 1) carboxylic acids and their salts; Three groups of anionic surfactants are particularly effective: 2) sulfonic acids and their salts; 3) sulfuric acid and sulfite ester salts. The classification and structural formula of these active agents are described in detail in Takao Karime et al., "Surfactant Analysis Method", Saiwai Shobo, Japan Surfactant Industry Association, "Surfactant List". The amount used is 0.001% to 10% of the liquid to which the surfactant is added, or 0.01g per liquid.
to 100g of surfactant, preferably 0.1g to 10g
Good amount. It is characterized in that at least one kind of anionic surfactant is added to at least the emulsion layer. The silver halide emulsion used in the present invention is fine-grained silver halide, preferably with an average grain size of 0.05 μm or more.
It is about 0.3μ. Also, those with good monodispersity are preferable. The method for preparing silver halide may be any known method such as forward mixing, back mixing, and simultaneous mixing. The silver halide emulsion obtained by the present invention contains additives used in general photographic emulsions such as stabilizers, covering power improvers, anti-irradiation agents, film property improvers, hardeners, matting agents, and developing agents. and coated on a known support. It may have other hydrophilic colloid layers such as a protective layer and an undercoat layer. The photosensitive material for bright room use obtained according to the present invention is exposed to light from a light source rich in ultraviolet light mainly used in the field of printing, such as a mercury lamp, an ultra-high pressure mercury lamp, a metal halide, and the like. The photosensitive material for bright room use obtained according to the present invention can be safely handled for a long time under bright room light both before and after the above-mentioned exposure. Example 1 Silver halide was precipitated in a conventional manner using 100 mg of adenine and 10 ^-6 moles of rhodium chloride per mole of silver chlorobromide containing 95 mol% of silver chloride, and physical ripening was performed to obtain an average grain. An emulsion with a diameter of 0.2 μm and a narrow particle size distribution was obtained. After desalting and redissolving this emulsion, 500 mg of pinacryptol yellow per mole of silver halide and thiosalicylic acid were added as organic desensitizers.
Add 400mg and further add hardener and various surfactants to produce 3.5g/ ^m2 of silver on polyester film.
It was coated together with the gelatin solution for the protective layer and dried. The surfactants used were fatty acid monocarboxylate (Airol OP, manufactured by Toho Chemical Co., Ltd.) as a representative of anionic surfactants, polyoxyethylene alkyl ether (Actinol K, manufactured by Matsumoto Yushi Co., Ltd.) as a representative of nonionic surfactants, A representative example of a cationic surfactant is a tetraalkylammonium salt (Zontes TL, manufactured by Matsumoto Yushi Co., Ltd.), and a representative example of an amphoteric surfactant is betaine (Sunstat, manufactured by Sanyo Chemical Co., Ltd.).
1007) to investigate its characteristics. The amount added is 0.5 to 3.0 g per emulsion. Two copies of each of these samples were exposed using a bright room printer through film with a density difference. One sheet was processed under a yellow safelight, and the other sheet was processed after being exposed to 1000 lux for 1 hour under a fluorescent light with UV removed. Development was performed at 38°C for 23 seconds using a developer containing phenidone and hydroquinone, followed by fixing, washing with water, and drying. The sensitivity of a sample that was not exposed under a white fluorescent lamp from which ultraviolet rays were removed was set as 100, and the sensitivity of a sample that was exposed to a fluorescent lamp was determined and used as a guideline for handling in a bright room. In other words, the sensitivity after exposure under fluorescent light is 100.
It can be said that the higher the value is, the better it is. These results are shown in the table.

[Table] As shown in the table, the samples containing anionic surfactants exhibit very little desensitization in a bright room. In addition
No obvious difference could be observed at 500 lux for 30 minutes. This phenomenon is extremely unique and completely unexpected for photography researchers. Example 2 Next, various anionic surfactants were tested. The conditions are the same as in Example 1. These results are shown in the table.

[Table] As shown in the table, anionic surfactants have less desensitization in a bright room. Particularly effective are carboxylates, sulfonates, and sulfate ester salts. The fact that surfactants affect photographic properties in this way is very specific, and is particularly noticeable in light-sensitive materials for use in bright rooms.

Claims (1)

[Claims] 1. A negative fine-grain silver halide photographic emulsion containing at least 80 mol % of silver chloride, and at least one of each of an organic desensitizer and a 2-mercaptobenzoic acid whose sum of polarographic anode potential and cathode potential is positive; A silver halide photographic emulsion characterized by containing an anionic surfactant.