JPH05273687A - Silver halide photographic emulsion - Google Patents

Abstract

PURPOSE:To restrain desensitization due to light in a light room and humidity and to enhance sensitivity to a printer light source by incorporating a specified compound and a mercaptobenzoic acid derivative in a specified fine silver halide grain photographic emulsion specified in pH. CONSTITUTION:The silver halide photographic emulsion containing fine silver halide grains having an average grain diameter of <=0.15mum and comprising at least 80mol% silver chloride and at least one kind of the compound represented by formula and at least one kind of the 2-mercapt benzoic acid derivative. In formula, each of R1 and R2 is a saturated or unsaturated aliphatic group, and X is an anion, such as Cl, Br, I, p-toluene-sulfonic acid ion, or the like. This emulsion is controlled to a pH of <=5.2. It is preferred to add this compound of formula to the silver halide emulsion layer in an amount of 0.01mg-5g, especially, 0.1mg-3g per 1mol of silver halide at an optional time before coating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver halide photographic emulsion, and more particularly to a silver halide photographic emulsion suitable for a light room light-sensitive material.

[0002]

2. Description of the Related Art Recently, in the field of printing, due to the complexity of printed materials and the development of scanners, it has been desired to improve the efficiency of the returning work process. Therefore, a photographic film with an ultra-low sensitivity of about 10 ^-3 to 10 ^-5 has been developed compared to the conventionally used return film, and it can be handled in a bright room (under a white fluorescent lamp excluding ultraviolet rays). It is used as a return film, that is, as a light-sensitive material for bright rooms. The performance required for such a bright room photosensitive material is that it has a high contrast and a sufficient maximum density, can be handled for a long time in a bright room, and has high sensitivity to a printer light source. , Even when used under various environments, its performance is minimally changed.

As a silver halide emulsion for a light-sensitive room light-sensitive material, a large amount of rhodium salt is used as an inorganic desensitizer 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 generally used in direct positive silver halide emulsions. However, even the emulsions produced by these methods have a serious drawback that they cannot guarantee sufficient safety as a light-sensitive material for a bright room in handling in a bright room. On the other hand, as described in JP-A-59-177537, handling in a bright room by using an organic desensitizer and a 2-mercaptobenzoic acid having a positive sum of polarographic anode potential and cathode potential Techniques for improving safety are disclosed. However, a light-sensitive material using this halogenated emulsion shows a marked decrease in sensitivity when used under high humidity, and is not satisfactory as a light-sensitive material for a bright room. It is desired to develop a light-sensitive material for a bright room, which can be handled, has high sensitivity to a printer light source, and is not affected by humidity in photographic characteristics.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a light-sensitive material for a bright room, which can be handled in a bright room for a long time, has high sensitivity to a printer light source, and whose photographic characteristics are not affected by humidity. Another object of the present invention is to provide a silver halide emulsion suitable for.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that halogenated fine particles containing at least 80 mol% of silver chloride and having an average particle size of 0.15 μm or less. The silver photographic emulsion contains at least one of each of the compound of Chemical formula 1 and 2-mercaptobenzoic acid, and the pH of the halogenated emulsion is 5.2 or less. Has been found to be achieved.

In the chemical formula 1, R1 and R2 each represent a saturated or unsaturated aliphatic group. X represents an anion such as chlorine ion, bromide ion, iodide ion, P-toluenesulfonate ion and the like.

Chemical formula 1 is preferably contained in the silver halide emulsion layer, and its addition amount can vary widely depending on its type, the emission wavelength of the light source used for exposure, the intensity, etc. , 0.01 mg to 5 g, and preferably 0.1 mg to 3 g, per mol of silver halide.
The compound of Chemical formula 1 can be added at any time before coating. An example is shown below.

[0008]

[Chemical 2]

[0009]

[Chemical 3]

[0010]

[Chemical 4]

[0011]

[Chemical 5]

[0012]

[Chemical 6]

[0013]

[Chemical 7]

[0014]

[Chemical 8]

[0015]

[Chemical 9]

The 2-mercaptobenzoic acids used in the present invention include, in addition to thiosalicylic acid, thiosalicylic acid substituted with an alkyl group, an alkoxy group, an amino group, an acylamino group, a halogen atom or the like, and further a mercapto group. And those having a protecting group such that S-acetylthiosalicylic acid, S-methylcarbamoylthiosalicylic acid, S-phenylcarbamoylthiosalicylic acid and S-ethoxycarbabonylthiosalicylic acid can be mentioned.

These thiosalicylic acids are known, for example, in JP-A-56-8145. The addition timing of these thiosalicylic acids may be any timing in the emulsion manufacturing process, and the addition amount thereof can be appropriately selected generally in the range of about 20 mg to about 5 g per mol of silver halide. Of course, if necessary, other antifoggants or stabilizers can be further used.

The silver halide emulsion used in the present invention is silver chloride or silver chlorobromide, silver chloroiodide or silver chlorobromoiodide containing at least 80 mol% of silver chloride. The silver halide emulsion used in the present invention has an average grain size of 0.15 μm or less. Further, 90% or more of all particles have an average particle size of ± 10%.
Those having a particle size in the range of are preferred. The silver halide emulsion may be prepared by any known method such as forward mixing, reverse mixing and simultaneous mixing. The emulsion that has undergone physical ripening is
After desalting, it is preferable that the necessary additives are added before coating, but the desalting treatment can be omitted. It is preferable that chemical sensitization is not substantially carried out, but it may be carried out if desired.

The silver halide emulsion used in the present invention is
Stabilizers, antifoggants, covering power improvers, film physical property improvers, surfactants, hardeners, matting agents, developing agents and other additives used in general photographic emulsions can be included, and coating known Is coated on a support. You may have other hydrophilic colloid layers, such as a protective layer and an undercoat layer.

The bright room light-sensitive material obtained by the present invention is
It is exposed by a light source rich in ultraviolet light mainly used in the printing field, for example, a mercury lamp, an ultra-high pressure mercury lamp, a metal halide or the like.

[0021]

Example: Average particle size of 0.13μ containing 95 mol% of silver chloride
A silver chlorobromide emulsion composed of cubic crystals of m was prepared by the double jet method, desalted by the flocculation method, washed with water and redissolved, and then the compound of Chemical formula 1, the 2-mercaptobenzoic acid and the comparative compound were shown in Table 1. After addition of a hardening agent and a surfactant, the pH was adjusted as shown in Table 1, and 5 g / g of silver nitrate was added on the polyester film.
It was applied together with the gelatin solution for the protective layer so as to have m ^2, and dried.

The comparative compounds are:

[0023]

[Chemical 10]

Each of these samples was subjected to an environment of 23 ° C. and 50% RH, and a bright room printer P- manufactured by Dainippon Screen Co., Ltd.
After exposure for sensitometry using 627-FM, development, fixing, washing with water and drying at 38 ° C. for 20 seconds with MRA-CD-111 developing solution manufactured by Mitsubishi Paper Mills and MRA-CF-711 fixing solution manufactured by Mitsubishi Paper Mills. Was performed using an automatic processor (LD-221QT manufactured by Dainippon Screen Mfg. Co., Ltd.).
The developed sample is a Macbeth transmission densitometer (RD91
The transmission density was measured in 7) and the photographic characteristics were calculated.

Further, in order to check the safety in a bright and bright room, after exposure in the same manner as above, under the fluorescent lamp (200 lux) in which a fine light sleeve manufactured by Fuji Photo Film Co. was attached to the emulsion surface of these samples. After being left for 30 minutes, the same development processing as above was performed and the same photographic characteristics were evaluated.

In order to see the effect of humidity during exposure,
After the above exposure was carried out at 23 ° C. and 80% RH, the same development processing as above was carried out and the same photographic characteristics were evaluated.

The results are shown in Table 1. As for the stability under humidity and bright room light, the sensitivity when exposed at 23 ° C 50% and developed as it is is set to 100, and 2
The relative sensitivities (high humidity) of those exposed at 3 ° C and 80%, and the relative sensitivities (under bright room) when left under the above-mentioned fluorescent lamp after exposure are shown.

[0028]

[Table 1]

[0029]

The results shown in Table 1 show that the emulsion of the present invention has little desensitization under bright room light and is significantly improved in desensitization due to humidity.

Claims (1)

[Claims] 1. Containing at least 80 mol% silver chloride,
The fine grain silver halide photographic emulsion having an average grain size of 0.15 μm or less contains at least one of the compound of the following chemical formula 1 and 2-mercaptobenzoic acid, and the pH of the halogenated emulsion is 5.2 or less. A silver halide photographic emulsion characterized by: [Chemical 1] In Chemical formula 1, R1 and R2 each represent a saturated or unsaturated aliphatic group. X represents an anion.