JPH05313287A - Silver halide photographic emulsion - Google Patents

Abstract

PURPOSE:To obtain the silver halide photographic emulsion containing an effective intense color sensitizer. CONSTITUTION:The silver halide photographic emulsion contains the compound represented by formula I in which R is H, alkyl, aryl, aralkyl, or a heterocyclic group; and n is 1, 2, or 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION Spectral sensitization is an important technique in the production of silver halide photographic emulsions. By using a sensitizing dye and another compound (this is called a supersensitizer),
It is known that the spectral sensitivity is higher than that of the dye alone, and this method is called supersensitization or supersensitization. The present invention relates to this method of supersensitization.

[0002]

2. Description of the Related Art Supersensitization is a well-known technique in the field of silver salt photography. The theory is, for example, James, T.
H., The Theory of the photographic process P.259-26
1, Macmillan Publishing (New York 1977) and Sturge
JM, Neblettes Handbook of Photography P.92-96,
Litton Education Publishing (New York 1977), Gilm
an, Jr.PB, Photographic Science and Engineering 18
418-428 (1974).

In summary, the action of supersensitizers (1) increases the light absorption of the dye (including the intensification of the J band),
(2) Helps the adsorption of dyes on the silver halide surface,
(3) Trapping of the dye hole (electron transfer from the supersensitizer to the dye hole). In order to carry out supersensitization by the mechanism of (3), the oxidation potential of the supersensitizer (hereinafter referred to as Eox
Must be smaller than that of the dye molecule. A well-known compound satisfying this condition is a dialkylaminostyryl-based compound. Most of the others, except this compound, are sensitizing dyes,
The combination of two or more dyes is this type of supersensitization.

However, there are compounds known to trap dye holes even though Eox is larger than the dye, for example. For example Tani T, Photographi
C science and Engineering 23 240 (1979) uses ESR that 4-hydroxy-6-methyl-1,3,3a, 7-tetraazaindene (TAI) traps dye holes and supersensitizes. Have been proven. Further, JP-A-51-81613 discloses that benzotriazole substituted with at least one halogen atom is supersensitized, but it does not seem to have such a high effect. Supersensitization by phenols and hydroquinone derivatives is also known, but there is a problem in stability over time.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a silver halide photographic emulsion containing an effective supersensitizer.

[0006]

As a result of intensive studies, the present inventors have found that a crown compound (Chemical Formula 2) having a function of a metal chelating agent is an effective supersensitizer.

[0007]

[Chemical 2]

In the formula, R represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heterocyclic group, and n is an integer of 1 to 3.

Representative specific examples of the supersensitizer of the present invention are shown below.

[0010]

[Chemical 3]

[0011]

[Chemical 4]

[0012]

[Chemical 5]

[0013]

[Chemical 6]

[0014]

[Chemical 7]

[0015]

[Chemical 8]

[0016]

[Chemical 9]

[0017]

[Chemical 10]

[0018]

[Chemical 11]

[0019]

[Chemical formula 12]

[0020]

[Chemical 13]

[0021]

[Chemical 14]

[0022]

[Chemical 15]

[0023]

[Chemical 16]

The crown compound of the compound of the present invention is a compound of Journal of Organic Chemistry [J.org.che
m. 57 542 (1992)].

The sensitizing dye used in the present invention is preferably a cyanine dye represented by the following chemical formulas 17, 18 and 19.

[0026]

[Chemical 17]

[0027]

[Chemical 18]

[0028]

[Chemical 19]

In the formula, R ³ and R ⁴ may be the same or different and each represents an alkyl group or a sulfoalkyl group, and R ⁵ represents a hydrogen atom, an alkyl group or an aryl group. R ⁶ and R ⁷ may be the same or different and each represents an alkyl group or an aryl group. D is composed of 3 methylene groups to form a 6-membered ring. This 6-membered ring may be substituted with a lower alkyl group. E is composed of two methylene groups to form a 5-membered ring, and the 5-membered ring may be substituted with a lower alkyl group. Z ₁ or Z _{2 is} a 5- or 6-membered nitrogen-containing heterocyclic compound, for example, thiazole, benzothiazole, naphthothiazole, oxazole, benzoxazole, naphthoxazole,
It forms quinoline, benzoquinoline, benzimidazole, selenazole, benzoselenazole, indolenine, benzoindolenine, thiazoline, oxazoline ring and the like. X ⁻ is an anion and represents a chlorine anion, a bromine anion, a tosylate anion and the like. Also, n is 0, 1, 2,
Or 3.

The sensitizing dyes represented by Chemical formulas 17, 18 and 19 are well known compounds and are described in US Pat.
No. 457,078, No. 3,619,154, No. 3,6
82,630, 3,690,891, 3,69
5,888, 4,030,932, 4,36
It can be synthesized by the method described in 7,800. Examples of the sensitizing dyes represented by Chemical formulas 11, 12, and 13 are shown below, but are not limited to these examples.

[0031]

[Chemical 20]

[0032]

[Chemical 21]

[0033]

[Chemical formula 22]

[0034]

[Chemical formula 23]

[0035]

[Chemical formula 24]

[0036]

[Chemical 25]

[0037]

[Chemical formula 26]

[0038]

[Chemical 27]

[0039]

[Chemical 28]

[0040]

[Chemical 29]

[0041]

[Chemical 30]

The amount of the cyanine dye added is usually an amount sufficient for spectral sensitization, that is, 10 ^-6 to 10 -1 mol of silver halide.
^-3 mol range, particularly preferably 5 x 10 ^-6 to 1
It is in the range of × 10 ^-4 mol. Further, the addition of the sensitizing dye to the silver salt emulsion is usually carried out in a suitable solvent (eg water, methanol, DM).
It is preferable to dissolve it in F etc.) and add it as a solution.

The supersensitizer of the present invention may be added before, after, or at the same time as the addition of the sensitizing dye, and the addition method is preferably a solution. The solvent used may be the same as that used for the sensitizing dye, but in the case of water, it is effective to add a small amount of caustic.

Preparation of Supersensitizer 2 and Sensitizing Dye 1 of the present invention
When 7, 7, or 19 is used in combination, the molar ratio of the supersensitizer to the sensitizing dye is 40/1 to 1/10, preferably 5/1 to 1/5.

The silver halide in the photographic emulsion used in the method of the present invention may be any of silver chloride, silver bromide, silver chlorobromide, silver iodobromide, etc., but especially silver bromide or iodoodor. Silver iodide (in particular, silver iodide content of 10 mol% or less) has a great effect. The binder of the emulsion is gelatin, but part or all of it is replaced with natural polymers such as gelatin derivatives, albumin, agar, gum arabic, alginic acid, and synthetic polymers such as polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylamide. May be.

The silver halide emulsion used in the present invention may be coarse grains, fine grains or mixed grains thereof, and these can be prepared by a known method, a single jet method or a double jet method. Further, the crystal structure of the silver halide grains may be uniform to the inside or may have a so-called layered structure in which the inside and the outside are different. It may be of the surface or internal latent image type. These are James' The theory of photog
raphic process "(MacMillan), Glafkides" Phot
It can be prepared by a generally accepted method such as ammonia method, neutral method, acidic method, etc., which is also described in the literature such as “graphic chemistry” (Fountain Press).

The average diameter of the silver halide grains is not particularly limited, but 0.04 μm to 2 μm is particularly preferable. The particle size distribution may be narrow or wide. The silver halide emulsion may or may not be physically ripened. The silver halide emulsion may or may not be chemically sensitized. As the chemical sensitization method, those described in the above-mentioned publications can be used. An antifoggant such as tetraazaindene may be added to the photographic emulsion spectrally sensitized by the method of the present invention to stabilize storage. Further, the film can be hardened by a commonly used hardener.

In the photographic emulsion sensitized by the present invention, for example, an anionic or nonionic surface active agent can be used as a coating aid or for the purpose of antistatic. The support on which the emulsion is coated may be paper, film, glass plate, metal plate, or the like.

[0049]

EXAMPLES The present invention will be described in detail below with reference to examples.

Example 1 Using a double jet method, the average particle size was 0.7 μm.
A cubic AgBr emulsion of was prepared. That is, AgNO ₃ and KBr aqueous solution were simultaneously added while the pAg was kept constant while the gelatin aqueous solution was well stirred. This emulsion contains 0.38 mol of AgBr / Kg and about 45 g of gelatin. From the emulsion thus prepared, 2 kg was sampled, and 1% by weight of sodium thiosulfate (5
6.7 ml of water salt) was added, and the mixture was aged at a temperature of 50 ° C. for 1 hour.
Further, divide the emulsion into 100 g portions, and add 0.1% of the sensitizing dye.
Methanol solution and 5 ml of 10 ^-2 mol / l methanol solution of supersensitizer were added, and each of them was dried on a cellulose acetate film provided with a gelatin subbing layer to give a film thickness of about 4μ. Coating was carried out to prepare a photographic light-sensitive material.

Each sample was exposed by a tungsten bulb (color temperature 2854 ° K) for 10 seconds through a continuous wedge and a color filter. The color filter is a blue filter (Fuji Photo Film BPN-45),
I used a yellow filter (minus blue, Toshiba glass filter). After exposure, 2 with methol and ascorbic acid developer
It was developed at 0 ° C. for 10 minutes. The composition of the developer is as follows.

Metol 2.5 g Ascorbic acid 10 g KBr 1.0 g Nabox 35.0 g Water is added to make 1 l (pH 9.8).

The photographic speed is represented by the reciprocal of the exposure amount required to give a photographic density of fog + 0.1. The blue sensitivity and the minus blue sensitivity are the relative sensitivities obtained by using the above filters. Addition amount is mmol / A
gBr mol.

[0054]

[Table 1]

[0055]

[Table 2]

[0056]

[Table 3]

As is clear from the sensitivity values in Tables 1 to 3,
The supersensitizer of the present invention alone increases the intrinsic sensitivity (blue sensitivity), but when used in combination with the sensitizing dye, the intrinsic sensitivity and spectral sensitivity are further increased.

Example 2 An emulsion consisting of octahedral silver bromide grains having an average grain size of 0.7 μ was prepared and sulfur-sensitized in the same manner as in Example 1. This was similarly exposed and developed to prepare Tables 4 and 5.

[0059]

[Table 4]

[0060]

[Table 5]

Example 3 The amount of dye was fixed at 0.24 mmol / mol AgBr, and the amount of supersensitizer was fixed at 1.3 mol / mol AgBr, and evaluation was conducted in the same manner to prepare Table 6.

[0062]

[Table 6]

[0063]

[Chemical 31]

[0064]

[Chemical 32]

Example 4 A cubic silver chloride emulsion having an average grain size of 0.3 μm was prepared by using a conventional double-mixing method. That is, the aqueous silver nitrate solution and the aqueous potassium chloride solution were simultaneously added while the aqueous gelatin solution was well stirred. This emulsion contains 0.29 mol of silver chloride per Kg and about 45 g of gelatin. 2 Kg of the emulsion thus obtained is 0.1
% Sodium thiosulfate (13.3 ml) was added and sulfur sensitization was performed at 50 ° C. for 1 hour. The emulsion is further divided into 50 g each, and 0.
Add 2 ml of 1% dye in methanol, and add 10 ^-2
A methanol solution of a supersensitizer (ml / l) was added, and these were coated on a cellulose acetate film provided with a gelatin subbing layer so as to have a thickness of 4 μm after drying. The exposure and development were the same as in Example 1.

[0066]

[Table 7]

Example 5 Cubic silver iodobromide (1 mol% silver iodide) having an average particle size of 0.6 μm was prepared. Sulfur sensitization was performed in the same manner as in Example 1. This photosensitive material was exposed and developed in the same manner as in Example 1.

[0068]

[Table 8]

[0069]

EFFECTS OF THE INVENTION By using the supersensitizer of the present invention in combination with a sensitizing dye, supersensitization occurs and the spectral sensitivity can be effectively increased.

Claims (1)

[Claims] 1. A silver halide photographic emulsion comprising the compound of the following chemical formula 1. [Chemical 1] (In the formula, R represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and n is an integer of 1 to 3.)