JPS5854378B2 - Spectrally sensitized silver halide photographic emulsion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to silver halide photographic emulsions, particularly silver halide photographic emulsions spectrally sensitized by two sensitizing dyes.

It is well known that spectral sensitization is used as a technique for producing silver halide photographic emulsions.

It is well known that a combination of two or more sensitizing dyes is used for spectral sensitization, particularly in the visible light region.

The intensity of spectral sensitization is influenced by the chemical structure of the sensitizing dye, the properties of the emulsion (for example, the composition of silver halide, crystal habit, crystal system, silver ion concentration, hydrogen ion concentration, etc.).

Furthermore, the spectral sensitivity is also influenced by photographic additives such as stabilizers, anti-capri agents, coating aids, precipitants, and color couplers that coexist in the emulsion.

In addition, in spectral sensitization, increasing the amount of sensitizing dye added to the silver halide emulsion increases the intensity of spectral sensitization, but contrary to this effect, there are side effects that are harmful to photographic properties. It is also well known that this occurs.

One of them is the occurrence of fog due to the addition of sensitizing dyes.

When the light-sensitive material is photographic paper, even a very small amount of this capri is undesirable and significantly reduces the commercial value.

Another is the suppression of development due to adsorption of the sensitizing dye to silver halide.

For example, when the amount of the sensitizing dye represented by the general formula [IIl] is increased, the spectral sensitization intensity increases correspondingly. At short distances, photographic sensitivity may actually decrease, and this is due to development inhibition by the adsorbed dye.

When two sensitizing dyes are combined, due to differences in the development inhibitory effects of each dye, the amount added of the dye combination that provides maximum sensitivity when the development time is sufficiently long may not be sufficient when the development time is relatively short. It may not give any sensitivity.

Another problem is that, for example, when the amount of the sensitizing dye represented by the general formula (■) is increased, the spectral sensitization intensity increases correspondingly, but the sensitivity of the silver halide specific absorption range (blue sensitivity) will actually decrease if the amount added exceeds a certain level.

A decrease in silver halide specific range sensitivity caused by this sensitizing dye leads to a decrease in white sensitivity, which is not desirable as a photographic light-sensitive material.

The above drawbacks are particularly unfavorable for light-sensitive materials (for example, black-and-white negative photographic materials, micronegative photographic materials, etc.) made using orthopanchromatically sensitized photographic emulsions.

In the case of orthopanchromatically sensitized photographic materials, it is known from Japanese Patent Publication No. 48-42493 that the spectral sensitivity distribution has a significant effect on the improvement of tone reproduction.

As for the spectral sensitivity distribution, the red sensitivity distribution is 625 to 640n.
It is desirable to have a very thick spectral sensitivity in m, and a spectral sensitivity that gently extends to about 650 nm on the long wavelength side.

An object of the present invention is to provide a spectrally sensitized silver halide photographic emulsion which does not have an increase in fog caused by sensitizing dyes and has a small decrease in silver halide specific sensitivity.

Still another object of the present invention is to provide a spectrally sensitized silver halide photographic emulsion that has a small development inhibiting effect.

Furthermore, another object of the present invention is to provide a silver halide photographic emulsion that maintains high white light sensitivity of a light-sensitive material and has a gentle spectral sensitivity distribution up to about 650 nm without reducing the extreme sensitivity of 625 to 640 nm. Our goal is to provide the following.

The above object of the present invention is to provide a silver halide photographic emulsion with the general formula C.
This can be achieved by containing a combination of at least one of the sensitizing dyes represented by II) and at least one of the sensitizing dyes represented by the following general formula [■].

General formula (II) [However, Zl represents a sulfur atom or a selenium atom.

R2 represents an unsubstituted alkyl group or a substituted alkyl group.

R3 represents a substituted alkyl group. R1 represents a hydrogen atom or a lower alkyl group.

R5, R6, R9, and R10 may be the same or different, and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group,
Represents a hydroxy group, alkoxy group, carboxy group, alkoxycarbonyl group or acylamino group.

R4, R7, R8 and R11 may be the same or different and each represents a hydrogen atom or an alkyl group.

R4 and R5, R6 and R7, R8 and R9, R10 and R1,
1 may each form a benzene ring.

Xl- represents an acid anion.

m represents O or 1, and is O when forming an inner salt.

[General formula] [However, Z2 and Z3 each represent a sulfur atom or a selenium atom.

R12 and R13 each represent an unsubstituted alkyl group or a substituted alkyl group.

R15, R16, R19, and R20 are R5, R6, and R, respectively.
9, has the same meaning as R10.

R14, R17, R18 and R21 each represent a hydrogen atom or an alkyl group.

Xl represents an acid anion.

n represents 0 or 1, and when forming an inner salt, O
It is.

] In the above general formula, the unsubstituted alkyl groups of R2, R12 and R13 are preferably alkyl groups having 1 to 6 carbon atoms, particularly preferably alkyl groups having 1 to 4 carbon atoms.

Specific examples include methyl group, ethyl group, propyl group,
Examples include n-butyl group, i-butyl group, and n-hexyl group.

Regarding the substituted alkyl groups of R2, R3, R12 and R13, the alkyl moiety preferably has 1 to 6 carbon atoms, and 1 to 6 carbon atoms.
-4 is particularly preferred.

In addition, the substituted alkyl group may include a carbon atom in the alkylene chain replaced with an oxygen atom, such as a sulfophenyl group, a sulfo group, a carboxy group, a phenyl group, a carbamoyl group, an alkoxycarbonyl group having an alkyl moiety having 1 to 6 carbon atoms,
Substituted with a substituent such as a vinyl group.

Specific examples include cyclohexyl group, methoxymethyl group, methoxyethyl group, ethoxyether group, t-
Alkoxyalkyl group such as butoxyethyl group; β-sulfoethyl group, γ-sulfofurovir group, γ-sulfobutyl group, δ-sulfobutyl group, β-hydroxy-γ-sulfopropyl group, 2-γ-sulfopropoxyethyl group, 2
-Alkyl groups substituted with sulfo groups such as sulfophenethyl groups; Alkyl groups substituted with carboxy groups such as carboxymethyl groups, β-carboxyether groups, γ-carboxypropyl groups, and δ-carboxybutyl groups; benzyl groups , an alkyl group substituted with a phenyl group such as a phenethyl group or an r-phenylpropyl group; an alkyl group substituted with a carbamoyl group such as a carbamoylethyl group or a carbamoylpropyl group; a β-methoxycarbonylethyl group,
Alkoxycarbonyl alkyl groups such as β-ethoxycarbonylethyl group and r-ethoxycarbonylprobyl group;
Allyl group; alkyl group substituted with a hydroxy group such as β-hydroxyethyl group and γ-hydroxypropyl group;
Examples include phenoxyalkyl groups such as 2-phenoxyethyl group and 3-phenoxyprobyl group.

Lower alkyl for R1 is preferably an alkyl group having 1 to 4 carbon atoms, particularly preferably an alkyl group having 1 to 2 carbon atoms.

Specific examples thereof include methyl, ethyl, propyl, and butyl groups.

R5, R6, R9, R10, R15, B 16, R19
and R20 are each a hydrogen atom, a halogen atom, such as a chlorine atom, a bromine atom, etc.; an alkyl group preferably having 1 to 1 carbon atoms;
6, particularly preferably carbon number 1 to 4, such as methyl group, ethyl group, n-propyl group 1, i-propyl group, n-butyl group, t-butyl group; Aryl group preferably carbon number 6 to 12 carbon atoms, such as phenyl group and tolyl group; hydroxy group; alkoxy group, preferably 1 to 4 carbon atoms in the alkyl moiety, such as methoxy group,
Ethoxy group, butoxy group, etc.; Carboxy group; Alkoxycarbonyl group Preferably the alkoxy moiety has 1 to 1 carbon atoms
4, such as a methoxycarbonyl group, an ethoxycarbonyl group, an n-butoxycarbonyl group, a t-butoxycarbonyl group; and an acylamino group such as an acetylamino group, a propionylamino group, etc.

Among the sensitizing dyes represented by the general formula (I), those represented by the following general formula (IA) or (IB) are particularly preferred.

However, R101 represents a methyl group or an ethyl group.

R109 represents a halogen atom, a lower alkyl group or an alkoxy group.

(I-B) R2, R3, X, - and m each represent the general formula.

(2)], where R105 represents a hydrogen atom, a halogen atom, a lower alkyl group or an alkoxy group.

R101 has the same meaning as in general formula (IA).

R2, R3, Xv and m each have the same meaning as in general formula CI).

The lower alkyl group of R109 and R105 has 1 to 4 carbon atoms.
Particularly preferred is a methyl group or an ethyl group.

The halogen atom of RIOQ and R105 is, for example, a salt** chlorine atom or a bromine atom, but preferably a chlorine atom.

The alkyl moiety of the alkoxy group of R109 and R105 has 1 to 4 carbon atoms, and a methoxy group or an ethoxy group is particularly preferable.

Among the sensitizing dyes represented by the general formula (II), those represented by the following general formula (II-A) are particularly preferred.

However, Z2, Z3, R12, R13, X2- and n have the same meanings as in each general formula (II).

In the combination of sensitizing dyes of the present invention, the general formula CI
A combination of a dye represented by -A) and a dye represented by general formula (II-A) is particularly preferred.

Furthermore, a dye represented by the general formula (IB) and a dye represented by the general formula (II-
Combinations with dyes represented by A) are also preferred.

In general formulas (IA) and (IB) and general formula (■A), R3 and R12 are substituted with an alkyl group substituted with a sulfo group, an alkyl group substituted with a carboxyl group, or a carbamoyl group. In the present invention, L is preferably an alkyl group or an alkyl group substituted with a hydroxy group.

In general formulas (IA) and (IB) and general formula (IIA), R101 is an ethyl group, and R3 and R
12 is β-sulfoethyl group, γ-sulfopropyl group, r
-sulfobutyl group, δ-sulfophthyl group, β-hydroxy-γ-sulfopropyl-1 group, β-carboxyethyl group, γ-carboxyfurovir group, β-hydroxyethyl group, β-carbamoylethyl group, or β-sulfophenethyl group group, and R2 and R13 are a methyl group, ethyl group, n-propyl group, benzyl group, phenethyl group, phenoxyethyl group, γ-phenylpropyl group, rphenoxypropyl group, or R3, R
In the present invention, the same substituted alkyl group as 12 is particularly preferred.

In embodiments of the present invention, it is preferred to use substantially only a combination of a sensitizing dye of general formula [I] and a sensitizing dye of general formula [1''I).

However, the above combinations of dyes may be used in small relative amounts (e.g. 11 of the total weight of dyes of general formula [I]).
5 to 1/10), and other sensitizing dyes, such as thiacarbocyanine dyes substituted with an ethyl group at the meso position, may be further combined.

Next, some specific examples of sensitizing dyes used in the present invention will be listed.

The sensitizing dyes represented by general formula CI) and general formula CII) used in the present invention can be synthesized by known methods, such as FoM,
“The Cyanine Dyesa” by Hamer
nd Re1ated Compounds, ”I
tersciencePublishers, Ne
wYork (1964), those skilled in the art can easily synthesize them, and those not described can also be synthesized by similar methods.

The sensitizing dyes used in this invention are each advantageously employed at a concentration of about 2.times.10@-6 to 2.times.10@-4 moles per mole of silver halide in the emulsion.

The molar ratio of the dye of general formula [II] to the dye of general formula CI) (dye of general formula [I] to dye of general formula [■]) is used in a range of 2:1 to 1:10, preferably l: The ratio is preferably 1 to 1:8, particularly preferably 1:1 to 1:4.

The sensitizing dye used in the present invention can be directly dispersed into the emulsion.

In addition, these can be prepared by first using a suitable solvent, such as ehamenal alcohol, ethyl alcohol, methyl celonorb, acetone,
It can also be dissolved in water, pyridine or a mixed solvent thereof and added to the emulsion in the form of a solution.

Ultrasonic waves can also be used for dissolution.

Moreover, as a method of adding this sensitizing dye, US Pat.
9987, etc., a method in which a dye is dissolved in a volatile organic solvent, the solution is dispersed in a hydrophilic colloid, and this dispersion is added to an emulsion, Japanese Patent Publication No. 46-2418.
5, etc., in which a water-insoluble dye is dispersed in a water-soluble solvent without dissolving it, and this dispersion is added to an emulsion; as described in U.S. Pat. No. 3,822,135,
A method of dissolving a dye in a surfactant and adding the solution to an emulsion; A method of dissolving the dye using a red-shifting compound and adding the solution to an emulsion, as described in Japanese Patent Application No. 50-946 etc. should be used.

In addition, methods described in US Pat. No. 2,912,343, US Pat. No. 3,342,605, US Pat. No. 2,996,287, US Pat.

The sensitizing dyes may also be uniformly dispersed in the silver halide emulsion before being coated on a suitable support, but can of course be dispersed at any stage of the preparation of the silver halide emulsion.

Any known method can be used for photographic processing of the light-sensitive material produced using the present invention.

A known treatment liquid can be used.

The processing temperature is usually chosen between 18°C and 50°C, but 1
The temperature may be lower than 8°C or above 50'C.

In the present invention, a development process that forms a silver image (black and white photographic process) is advantageously applied.

The developer used in black-and-white photographic processing can contain known developing agents.

As developing agents, dihydroxybenzenes (e.g. hydroquinone), 3-pyrazolidones (e.g. 1-
phenyl-3-pyrazolidone), aminophenols (
For example, N-methyl-P-aminophenol), 1-phenyl-3-pyrazolines, etc. can be used alone or in combination.

The developing solution generally contains other known preservatives, alkaline agents, and
Contains H buffering agent, antifogging agent, etc., and further contains dissolving aid, color toning agent, development accelerator, surfactant, antifoaming agent, etc.
It may also contain water softeners, hardeners, viscosity-imparting agents, and the like.

In black and white development processing, various development times are applied to vary sensitivity, gradation, and graininess.

The standard development time is 7 to 10 minutes at 20'C, but if you want to suppress sensitivity and obtain a soft-toned, fine-grained image, use a development time of 4 to 6 minutes to obtain high sensitivity and high gradation. If desired, development times of 11 to 30 minutes can be used.

As the fixer, one having a commonly used composition can be used.

As the fixing agent, in addition to thiosulfates and thiocyanates, organic sulfur compounds known to be effective as fixing agents can be used.

The fixing solution may contain a water-soluble aluminum salt as a hardening agent.

In the photographic emulsion of the present invention, any of silver bromide, silver iodobromide, silver iodochlorobromide, silver chlorobromide and silver chloride may be used as the silver halide.

Preferred silver halide is silver iodobromide or silver iodochlorobromide containing 10 mol % or less of silver iodide.

Particularly preferred is silver iodobromide containing from 5 mol % to 10 mol % silver iodide.

The average grain size of the silver halide grains in the photographic emulsion (the grain size is the grain diameter in the case of spherical or approximately spherical grains, the ridge length in the case of cubic grains, and is expressed as an average based on the projected area) is not particularly limited. is preferably 3μ or less.

It is preferably 1.5 μ or less, but particularly preferably 0.8 to
It is 1.2μ or less.

The particle size distribution can be narrow or wide.
.

The silver halide grains in the photographic emulsion may have a regular crystal structure such as a cube or an octahedron, or an irregular crystal structure such as a spherical or plate-like structure.
It may have a crystalline form (egular) or a composite form of these crystalline forms.

It may also consist of a mixture of particles of various crystalline forms.

The silver halide grains may have different phases inside and on the surface, or may consist of uniform phases.

Further, the particles may be particles in which a latent image is mainly formed on the surface, or may be particles in which a latent image is mainly formed inside the particle.

Particles in which latent images are mainly formed on the surface are preferred.

The photographic emulsion of the present invention is based on P, Glafkides, Ch.
imieet Physique Photograp
hique (Published by Paul Monte1, 196
7 years), Photograph by G.F. Duffin
hic Emulsion Chemistry (T
heFocal Press, 1966), V
,L.

Makin ng an by Zelikman et al.
d CoatingPhotographic Em
ulsion (published by The Focal Press,
(1964) and others.

That is, any of the acidic method, neutral method, ammonia method, etc. may be used, and the method for reacting the soluble silver salt and soluble halogen salt may be any one-sided mixing method, simultaneous mixing method, or a combination thereof. .

It is also possible to use a method in which particles are formed in an excess of silver ions (so-called back-mixing method).

As one type of simultaneous mixing method, a method in which the pAg in the liquid phase in which silver halide is produced can be kept constant, that is, a so-called Chondrald double jet method can also be used.

According to this method, a silver halide emulsion having a regular crystal shape and a nearly uniform grain size can be obtained.

Two or more types of silver halide emulsions formed separately may be mixed and used.

In the process of silver halide grain formation or physical ripening,
A cadmium salt, a zinc salt, a lead salt, a dhallium salt, an iridium salt or a complex salt thereof, a rhodium salt or a complex salt thereof, an iron salt or an iron complex salt, etc. may be present.

Usually, soluble salts are removed from the emulsion after precipitation or physical ripening, and the long-known tardel water washing method, which involves gelatin gelatin, may be used. Precipitation methods using inorganic salts (e.g. sodium sulfate), anionic surfactants, anionic polymers (e.g. polystyrene sulfonic acid) or gelatin derivatives (e.g. aliphatic acylated gelatin, aromatic acylated gelatin, etc.)
flocculation) may also be used.

The process of removing soluble salts may be omitted.

The silver halide emulsion may be a so-called unripe (Pr1mltive) emulsion which is not chemically sensitized, but it is usually chemically sensitized.

For chemical sensitization, the Glafkidis, D.
Uffin and Zellikman et al. or edited by H. Fr.
P photography 5chcn P roz
essem it Si lberhalogeni
Akademis
che Verlaggeseilschaft,
(1968) can be used.

The silver halide emulsion used in the present invention has an antifoggant (
Antifoggant) and stabilizers (5tabi 1
izer).

As a compound, Product Licensing Index, Volume 92, P 107 r Antifogga
nts and 5 tabilizers J. may be used.

Silver halide emulsions contain a developing agent.

As a developing agent, “Develop” in Product Licensing Index, Volume 92, pp. 107-108
Those described in the section ing agents J can be used.

Silver halide is dispersed in colloids that can be hardened by various organic or inorganic hardeners.

As a hardening agent, those described in "Hardeners J" in Product Licensing Index, Vol. 92, p. 108 may be used.

Silver halide emulsions may contain coating aids.

As a coating aid, "coating aids" in Product Licensing Index, Vol. 92, p. 108.
Those described in Section J may be used.

Silver halide photographic emulsions may also contain antistatic agents, plasticizers, fluorescent brighteners, air antifoggants, and the like.

The silver halide emulsion used in the present invention has a vehicle as described in Product Licensing Index, Vol. 92, 10.
Page 8 “Vehicles section J (December 1971)
Use the vehicle listed in .

The silver halide emulsion is coated on a support along with other photographic layers if necessary.

The coating method is described in Product Licensing Index, Volume 92, page 109, “Coating procedure
The method described in Section ures J may be used.

Further, as the support, those described in "5upports JO" of Product Licensing Index, Vol. 92, page 108 can be used.

For the purpose of increasing sensitivity, increasing contrast, or accelerating development, the photographic emulsion of the present invention may contain, for example, polyalkylene oxide or its derivatives such as ethers, esters, and amines.
It may also contain thioether compounds, thiomo/1/folins, quaternary ammonium salt compounds, urethane derivatives, urea derivatives, imidazole derivatives, 3-pyrazolidones, and the like.

For example, US Pat.
Those described in No. 2021, No. 3808003, etc. can be used.

The photographic material produced according to the present invention may contain a water-soluble dye in the photographic emulsion layer or other hydrophilic colloid layer as a filter dye or for various purposes such as preventing irradiation.

Such dyes include oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, cyanine dyes and azo dyes.

Among them, oxonol dyes, hemioxonol dyes and merocyanine dyes are useful.

Dyes may be mordanted in certain layers by cationic polymers such as dialkylaminoalkyl acrylates.

In the photosensitive material produced using the present invention, when the hydrophilic colloid layer contains dyes, ultraviolet absorbers, etc.
They may be mordanted with cationic polymers and the like.

For example, British Patent No. 685475, US Patent No. 26753
No. 16, No. 2839401, No. 2882156, No. 30484, No. 87, No. 3184309, No. 3445
No. 231, West German Patent Application (OLS) No. 1914362,
Polymers described in JP-A-50-47624, JP-A-50-71332, etc. can be used.

Exposure to obtain a photographic image may be carried out using a conventional method.

That is, any of the various known light sources can be used, such as natural light (sunlight), a tungsten electric lamp, a fluorescent lamp, a mercury lamp, a xenon arc lamp, a carbon arc lamp, a xenon flash lamp, and a cathode ray tube flying spot.

Exposure times range from 1/1000 seconds to 1 second, which is normally used with cameras, as well as exposure times shorter than 1/1000 seconds, such as 1/1 using xenon flash lamps and cathode ray tubes.
Exposures of 0' to 1/106 seconds can also be used;
Exposures longer than seconds can also be used.

If necessary, the spectral composition of the light used for exposure can be adjusted using a color filter.

Laser light can also be used for exposure.

Alternatively, exposure may be performed using light emitted from a phosphor excited by electron beams, X-rays, r-rays, α-rays, or the like.

The feature of the present invention is that, as shown in the Examples, the combination of sensitizing dyes with small fog caused by the sensitizing dyes is a sensitizing dye of general formula CI) and a sensitizing dye of general formula [II, 1]. This can be achieved in combination with

A further feature of the present invention is that sufficient sunlight sensitivity and spectral sensitivity can be achieved even in a relatively short development time by the combination of the above-mentioned sensitizing dyes.

Furthermore, the present invention is characterized by having an extremely thick spectral sensitivity in the range of 625 to 640 mπ, and furthermore, in accordance with the long-wave A law, it has a gentle spectral sensitivity of about 650 nm.
A spectral sensitivity distribution suitable for orthopanchromatism having spectral sensitivity over the entire range can be obtained by the combination of the above-mentioned sensitizing dyes.

Furthermore, one of the features of the present invention is that the combination of the above-mentioned sensitizing dyes also has a so-called supersensitizing effect.

The above characteristics are preferable for orthopanchromatically spectrally sensitized light-sensitive materials, especially light-sensitive materials for black-and-white negative photography.

Preferred embodiments of the invention are shown below.

(1) A patent claim characterized by containing a combination of at least one sensitizing dye represented by general formula (IA) and at least one sensitizing dye represented by general formula (n-A) A silver halide photographic emulsion as described in the range.

(2) A patent characterized by containing a combination of at least one sensitizing dye represented by general formula (I-B) and at least one sensitizing dye represented by general formula (II-A) A silver halide photographic emulsion according to the claims.

(3) It is characterized by containing a combination of dyes consisting essentially of at least one sensitizing dye represented by general formula CI) and at least one sensitizing dye represented by general formula CI[). A silver halide photographic emulsion according to the claims.

(4) The halogenated compound according to the claims, characterized in that it contains a combination of dyes of the general formula [I[10] used in a molar ratio of 1:1 to 1:4 to the dye of the general formula CI). Silver photographic emulsion.

(5) By using a combination of at least one sensitizing dye represented by the general formula [■] and at least one sensitizing dye represented by the general formula CII), the spectral spectrum can be spectralized to have extreme spectral sensitivity in the wavelength range of 625 to 640 nm. The silver halide photographic emulsion according to the claims, characterized in that it is sensitized.

(6) A photosensitive material for black and white negative photography having a silver halide emulsion according to any one of embodiments 0) to (5).

Example 1 Silver halide grains were formed by a single jet method, physically ripened by a conventional method, desalted, and further chemically ripened to obtain a silver iodobromide emulsion (iodine content: 6.5 mol %). .

The average diameter of the silver halide grains contained in this emulsion is 1.
It was 2 microns.

0.65 mol of silver halide was contained in 1 kg of this emulsion.

1 kg of this emulsion was weighed into a pot and dissolved in a constant temperature bath at 50°C.

A methanol solution of the sensitizing dye according to the present invention was added to the first
The amount shown in the table was added and mixed and stirred at 40°C.

Add 10 ml of a 1% by weight aqueous solution of 4-hydroxy-6-methyl-1,3,3a,7-titrazaindene, and add 2-
10 ml of a 1% by weight aqueous solution of hydroxy-4,6-cyclotriazine sodium salt was added, followed by 10 ml of a 1% by weight aqueous solution of sodium dodecylbenzenesulfonate, and the mixture was stirred.

This completed emulsion was coated on a cellulose triacetate film base to a dry film thickness of 5 microns and dried to obtain a sample.

This sample was cut into strips.

One is to use a sensitometer with a light source with a color temperature of 54,000, and the light source is a red filter (Ratsuten-25) manufactured by Eastman Kodak and a green filter (Ratsuten-25).
Ratten-58), same, blue filter (Ratten-47)
B) A light wedge exposure was performed.

The other was exposure to obtain a spectrogram using a diffraction grating type spectrograph.

Develop the following composition using a developer at 20°C for 7 minutes,
The strips were stopped, fixed, and washed with water to obtain strips with a predetermined black and white image.

The density was measured using a P-type densitometer manufactured by Fuji Photo Film Co., Ltd., and white light sensitivity (SW) and red light sensitivity (SR) were determined.
, green light sensitivity (SG), blue light sensitivity (SB), and fog were obtained.

The optical density of the reference point used to determine the sensitivity was [Capri +
0.20).

Composition of developer Metol water 00 anhydrous sodium sulfite 00 51 The results obtained are shown in Table 1 as relative values.

SW, SR, and SG are relative values relative to the value obtained by test A14 as 100, and SB is a relative value relative to the value obtained by test A1 as 100.

As is clear from Table 1, the combination of sensitizing dyes of the present invention provides better supersensitization in both red and green sensitivity than when each sensitizing dye is used alone.

For example, the dye (I-1) of Test &6 has almost no red sensitivity.

Furthermore, the dye (II-7) of Tess) A9 has relatively high red sensitivity.

When these two dyes are used together, the dye (
The sunlight sensitivity and red sensitivity of n-7) further increase, and the green sensitivity also increases significantly.

This situation can be seen by looking at the spectrum in Figure 1.
It can be clearly seen how the green sensitivity range increases at 550 nm.

Example 2 Combination of sensitizing dyes according to the present invention and Japanese Patent Publication No. 48-42
Comparing combinations of sensitizing dyes known in No. 493,
The results obtained are shown in Table 2.

The samples used here were the same as those described in Example 1, except that the sensitizing dyes and their amounts added were shown in Table 2, and the developer shown in Example 1 was heated at 20°C. The development time was changed to 4 minutes, 7 minutes, and 14 minutes.

In Table 2, Tess) A3 and O4 are Special Public Service No. 48-42493.
Indicates the dye combination of the number.

As is clear from Table 2, with the combination of sensitizing dyes of the present invention, high sensitivity can be obtained both at short and long development times, but when II-5 is increased as in Test 4,
At 4 minutes, fairly high sensitivity can be obtained, but at 4 minutes, the sensitivity is extremely low.

Therefore, by combining the sensitizing dyes of the present invention, high sensitivity can be obtained regardless of the length of development time.

[Brief explanation of drawings]

1 and 2 show spectral sensitivity curves obtained in Example 1. Curve 1 in Figure 1 is test) A6, curve 2 is test A9,
Curve 3 shows the spectral sensitivity curves obtained by Tess) A and 10, respectively. Curve 4 in Figure 2 is Tess) A6.3, song @5 is Tess) A
2. Curve 6 shows the spectral sensitivity curves obtained by Tess) A4.

Claims (1)

[Scope of Claims] 1 At least one sensitizing dye represented by the following general formula [■]
and at least one sensitizing dye represented by the general formula CID below.
A silver halide photographic emulsion characterized by containing a combination of General formula [■] [However, zl represents a sulfur atom or a selenium atom. R2 represents an unsubstituted alkyl group or a substituted alkyl group. R3 represents a substituted alkyl group. R1 represents a hydrogen atom or a lower alkyl group. R5, R6, R9, and R10 may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a hydroxy group, an alkoxy group, a carboxy group, an alkoxycarbonyl group, or an acylamino group. R4, R7, R8 and R11 may be the same or different and each represents a hydrogen atom or an alkyl group. R and R, R and RlR and R, and R and R may each form a ring. Xl- represents an acid anion. m represents O or 1, and when forming an internal salt, O
It is. ] General formula [■] [However, Z2 and Z3 each represent a sulfur atom or a selenium atom. Rl 2 and R13 each represent an unsubstituted alkyl group or a substituted alkyl group. R15, R16, R19, R20 are respectively R5, R6,
R9, synonymous with RIO. R14, R17, R18 and R21 each represent a hydrogen atom or an alkyl group. X2- represents an acid anion. n represents 0 or 1, and when forming an inner salt, O
It is. ]