JP2000066323A - Method for spectrally sensitizing flat plate silver halide grain - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emulsion contg. spectrally sensitized 111} flat plate silver halide grains showing improved sensitivity (speed) to visible green light emitted by sensitizing a screen with a green light emitting phosphor and to provide a method for manufacturing the emulsion. SOLUTION: In a method for manufacturing a flat platy silver halide emulsion, flat plate silver halide grains having an average aspect ratio of at least 2:1, 0.3-3.0 μm average grain diameter and <0.50 μm average thickness occupy at least 50% of the total projection area of the all grains. In the case that the manufacturing method contains steps for precipitating, spectrally sensitizing and chemically aging flat platy silver halide grains, the grains are spectrally sensitized before at least one J-zone flocculated dye and at least one non-J-zone flocculated dye is chemical aged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention relates to spectrally sensitized {111} tabular halogens exhibiting improved sensitivity (speed) to (preferably) visible green light emitted by an intensifying screen having a green light emitting phosphor. A method for preparing a photosensitive emulsion having silver halide crystals, said emulsion comprising a photosensitive silver halide photographic film material applicable in a radiographic film-screen combination comprising at least one X-ray intensifying screen in operative relationship with the film material. It is suitable for use in

[0002]

BACKGROUND OF THE INVENTION The effects of various precipitation conditions on the formation of silver halide emulsions containing tabular crystals, which have been widely studied as the tabular grains, have been known in the photographic industry for quite some time. Early in 1961, Berry et al.
The production and growth of tabular silver bromoiodide grains were announced in ographic Science and Engineering, Vol. 5, No. 6.
For a discussion of tabular grains, see Duffin, Photographic Emulsion Ch.
emistry, Focal Press, 1966, pages 66-72. Early patent documents include US-A 40639.
51; 4067739; 4150994; 418487
7 and 4184878. However, the tabular grains described therein cannot be regarded as exhibiting a high diameter to thickness ratio commonly referred to as the aspect ratio. In many US patent applications filed in 1981 and issued in 1984, tabular grains having high aspect ratios and their advantages in photographic applications are described, for example, in US Pat.
-A4434226; 4439520; 442542
5; 4425426 and 4433048. For an overview of high aspect ratio silver halide emulsions, see Research Disclosure, Vol.
Month, found in Item 22534.

The references cited above for tabular grains mainly relate to high-speed silver bromide or silver bromoiodide emulsions. Tabular grain emulsions having high aspect ratios are known to provide several advantages over conventional spherical grains, such as high covering power, high (spectral) sensitivity and low coating weight, which reduce manufacturing costs. The low coating weight is where rapid processing applications are required (which is a recurring requirement today)
Particularly preferred to.

[0004] Spectral sensitizing dyes are used in the field of photography.
Although well known for green and red sensitization, particularly for flat tabular grains, the number of examples is rather limited for blue and / or ultraviolet sensitization. It is further known to use a combination of a film material containing a green sensitized tabular grain emulsion and a green light emitting phosphor screen for radiography. After processing of the exposed emulsion grains, residual dye may be present, especially due to the presence of vast amounts of spectral sensitizing dye. This is because tabular grains have a large specific surface area capable of absorbing the enormous amount. These enormous amounts are preferred in terms of high speed and image quality (especially sharpness) required in diagnostic imaging where it is most important to reduce patient exposure to a minimum level.

A special layer arrangement developed to obtain the above-mentioned desired characteristics is described, for example, in JP-A 08006192,0.
8076305 and 09197625, EP-A 06
61592, 0693190 and 0770909 and U
SA 4585729, 5380636, 57189
94 and 5460916.

In mammographic applications in particular, for reasons of good image sharpness, the photosensitive layer is present on only one side of the film support, and imaging is performed in a system consisting of only one intensifying screen. Therefore, high speed, high contrast (preferably high "foot contrast") and low residual dye stain are desired. Special measures taken therefor are, for example, US-A 5,290,655, EP-A
0264788 and 0577027 and Research Discl
osure No. 33487 (1992), p. 161.

[0007]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a spectral sensitization exhibiting improved sensitivity (speed) to visible green light emitted by sensitizing a screen having a green light emitting phosphor. An object of the present invention is to provide an emulsion containing 111 ° tabular silver halide grains and a method for producing such an emulsion.

It is another object of the present invention to provide a radiographic screen-film combination comprising at least one X-ray intensifying screen in operation with a photographic material comprising tabular grains spectrally sensitized in the green spectral region. The particles are sensitive to low irradiation levels, whereas the post-exposure fog is low and no dye stain is present after processing.

A further object is to provide the desired high contrast for processed image clarity combined with high speed, low fog and the absence of dye stain, especially in mammographic applications.

[0010] Other objects will become apparent from the following description.

[0011]

SUMMARY OF THE INVENTION According to the present invention, silver bromide-rich materials having an aspect ratio of at least 2: 1, an average crystal diameter of from 0.3 .mu.m to 3.0 .mu.m and an average thickness of less than 0.50 .mu.m. A method of making a tabular silver halide emulsion wherein the tabular silver halide grains account for at least 50% of the total projected surface area of said grains, said method comprising the steps of precipitation, spectral sensitization and chemical ripening of said grains. In some cases, there is provided a production method characterized in that the emulsion grains are spectrally sensitized by adding at least one J-band aggregate and at least one non-J-band aggregate dye prior to chemical ripening.

An aspect ratio of at least 2: 1 and 0.3
a light-sensitive silver halide emulsion comprising tabular grains, wherein the tabular grains having an average crystal diameter of from .mu.m to 3.0 .mu.m and an average thickness of less than 0.50 .mu.m account for at least 50% of the total projected surface area of said grains. , And at least one J
Provided by the present invention is one having a band aggregating spectral sensitizing dye and at least one non-J band aggregating dye, wherein the material comprises a support, at least one hydrophilic colloid layer on at least one side of the support, and An X-ray material containing one or more photosensitive layers containing a silver halide photographic emulsion as described above is preferred.

Further, according to a preferred embodiment of the present invention, a radiographic screen-film combination comprising at least one X-ray intensifying screen in operative relation with the material as described above is claimed.

[0014]

DETAILED DESCRIPTION OF THE INVENTION Spectral sensitizing dyes, more preferably those of the J-band aggregation sensitizing type, are used in a sufficient amount to optimally sensitize tabular silver halide grains. Absorbed on top. For example, FM Hamer,
“Cyanine Dyes and Related Compounds” (196
4), p. 710, from J. Wiley, Interscience and T.
H. James, “The Theory of the Photographic Proces
s ", 4th Edition, MacMillan 1977, Chapter 8
As is well known in the photographic technology from U.S.A., the sensitizing maximum of a sensitizing dye in a silver halide emulsion, also called M-band sensitization due to molecular absorption, is located near the absorption maximum of a free dye in an aqueous solution. Certain sensitizing dyes have sharp sensitizing bands, or even peaks, at wavelengths slightly longer than the wavelength corresponding to the M-band sensitization maximum (about 20-50 nm). This is known as "J-band sensitization" and the dye is referred to as "J-band spectral sensitizing dye".
ctrally sensitizing dyes) ”or“ J-band aggregated dyes (J-
band aggregating dyes), while the opposite is the so-called “non-J-ba
nd aggregating dyes) ", which do not show the phenomenon of sharp bands or peaks as described above.

From the indirect data, the J-band aggregating spectral sensitizing dyes consist of nearly flat dye molecules adsorbed on the silver halide surface along their long edges, with their parallel stacked molecular planes forming a two-dimensional crystal. It is generally accepted that According to theoretical calculations, the deep color absorption shift, which is characteristic of the presence of J aggregation, depends on the angle of slip between successive molecular planes. The measurement of dye luminescence was especially useful for J-aggregation of gelatin-grown tabular silver bromide microcrystals.
Sp by Nov 8-13, 1992 by JEMaskasky
Most accurate to show J-aggregation as announced at the IS & T conference at ringfield. Recent literature is, for example, J. Phy
s. Chem. Vol. 101 (1997), p. 2149-2
153 relates to the thermodynamic analysis of repeated adsorption-desorption phenomena during the growth of said aggregation at the surface of silver halide grains. For example, analytical color fluorescence electron microscopy (ACFEM), ultra-low energy scanning electron microscopy (UL) to study the formation and properties of J-aggregates of cyanine dyes
Recently used techniques such as ESEM) and Atomic Force Microscopy (AFM) are described in J. Phys. Chem. Vol.
996), p. 17287-17296. A summary of the J-aggregation phenomena of spectral sensitizers with respect to structure and spectroscopy is further described in J. Soc. Phot.
Sci.Technol.Japan, Vol.59, p. 250-259. Prior studies of the sensitization efficiency of J-aggregates for silver bromide as a function of aggregate size by measuring the dependence of fluorescence lifetime and relative quantum yield were found in J. Phys. Chem.
Vol. 96 (1992), p. 2783-2790. The best known technique that has been used for a very long time is J. Aufzeich-nungsmaterialien (197
3) (for example, pages 157-180 and 237-25)
2) fluorescence and phosphorescence of the dye as described in the research paper.

According to the present invention, tabular silver halide grains having an average aspect ratio of at least 2: 1, an average crystal diameter of from 0.3 μm to 3.0 μm, and an average thickness of less than 0.50 μm are obtained by combining said tabular silver halide grains with said grains. At least 50 of total projected surface area
% Of a tabular silver halide emulsion comprising at least one J-band agglutination and at least one non-J-band agglutinated dye, wherein the method comprises steps of precipitation, spectral sensitization and chemical ripening. There is provided a production method characterized in that the particles are spectrally sensitized by being added before chemical ripening.

In one embodiment of the present invention, the J-band aggregated dye has a maximum J-band absorption in a wavelength range of 540 nm to 555 nm, and the non-J-band aggregated dye is less than 500 nm, more preferably 380 to 500 nm, and More preferably 42
A method is provided for absorbing radiation having a wavelength between 0 and 460 nm.

In another embodiment according to the present invention, there is provided a method wherein the J-band aggregate dye is a cyanine dye and the non-J-band aggregate dye is a merocyanine dye.

In a more preferred embodiment according to the method of the present invention, said cyanine dye corresponds to the formula:

Embedded image Wherein Z represents a nitrogen or oxygen atom; if Z is a nitrogen atom, it is substituted by R "; R, R 'and R" each independently represent a substituted or unsubstituted alkyl; and R "" is hydrogen. Represents a substituted or unsubstituted alkyl or substituted or unsubstituted aryl, T and T ′ each independently represent a known ordinary substituent, and (X ⁻ ) _p represents a group for compensating for the positive charge existing on the dye. Represents a negatively charged atom or group of atoms, (M ⁺ ) _q represents a positively charged atom or group of atoms for compensating for the negative charge present on the dye, and p and q each independently represent Represents an integer for obtaining an electrically neutral compound.

Further preferred embodiments of the method according to the invention
In the formula (I), R "" is -C₂H₅In
Z is an oxygen atom and at least one of R and R '
Is a sulfoalkyl group, preferably of the formula-(CH₂)_nS
O₃ ⁻(N is equal to 2, 3 or 4),-(CH₂)₂
-CH (CH₃) -SO₃ ⁻And -CH₂-CHY-C
H₂-SO₃ ⁻(Y represents -OH or -Cl)
-A sulfatoalkyl group, preferably of the formula-(CH₂)
_nOSO₃ ⁻(N is equal to 2, 3 or 4)
An acylsulfonamide group, preferably of the formula-(C
H₂)_n-C (O) -N (R "")-SO₂− (C
H₂)_mH (n is equal to 1, 2, or 3, m is 1, 2, 2,
3, etc.),-(CH₂)_r-SO₂-N
(R "")-SO ₂− (CH₂)_sH (r is a few
Or 4 and s is equal to 1, 2, 3, etc.),-
(CH₂)_v-SO₂-N (R "")-C (O)-
(CH₂)_wH (v is equal to 2, 3 or 4, w is 1,
2, 3 and the like, wherein the R "" "is H or alkyl
A carboxyalkyl group, preferably of the formula-(CH₂)
_x-COOH or-(CH₂)_x-COO⁻(X is 1,
(Equal to 2, 3). T and T 'are each German
Standing, 5-phenyl, 5-Cl, 5-OCH₃And 5-
CH₃Represents

Further preferred embodiments according to the method of the present invention
In the above formula (I), R "" is hydrogen, and Z is
T is 5-phenyl, 5-Cl, 5-O
CH ₃Or 5-CH₃And T 'is 5,6- (C
l)₂5-CN-6-Cl; 5-CF₃-6-Cl;
5-Cl; 5-CN, 5-CF₃, 5-CHF₂, 5-
SO₂CH₃Or 5-SO₂R '' '' '' '
(R ′ ″ ″ is a fluorine-substituted or non-fluorine-substituted alkyl
Represents a group), and 5-SO₂−N (R^x) (R^y)or
Is 5-CO-N (R^x) (R^y) (R^xAnd R^yIs it
Each independently represents a substituted or unsubstituted alkyl group;
May form a ring with the N atom to which they are attached)
Represents

In an even more preferred embodiment according to the process of the present invention, in formula (I) above, Z represents oxygen, T and T 'each represent Cl or T represents Cl and T' represents phenyl. And vice versa, and R and R ′ are of the formula — (CH ₂ ) _n SO ₃ ⁻ (n equals 2, 3 or 4), — (CH ₂ ) ₂ —CH (CH ₃ ) —S
O ₃ ^— and —CH ₂ —CHY—CH ₂ —SO ₃ ^— (Y represents —OH or —Cl);
R has the formula corresponding to the formula given above _{- (CH 2) j H (} j equals 1, 2, 3 or _{4), - CH 2 -Phen-} S
^{_{O 3 -, -CH 2 -Phen-}} COOH, - (CH
₂ ) Combined with R 'corresponding to _k- Phen-COOH (k equals 1, 2 or 3).

In a particular embodiment according to the method of the present invention, said spectral sensitizer is anhydro-5,5'-dichloro-
3,3'-bis (n-sulfobutyl) -9-ethyloxacarbocyanine hydroxide or anhydro-5
5'-dichloro-3,3'-bis (n-sulfopropyl) -9-ethyloxa-carbocyanine hydroxide.

According to the method of the present invention, the non-J-aggregating dye used in combination with the J-aggregating dye as described above corresponds to the general formula (II):

Embedded imageWherein Y is required to form a heterocyclic 5- or 6-membered ring
Q represents S, NR³, O, or-(C =
O) -N (R⁴)-; M⁺Represents a cation
N 'is equal to 0, 1 or 2; b is equal to 0 or 1
K; R¹, R², R ³And R⁴Are each independently C₁
-C₅Represents an alkyl chain,², R³And R⁴Little
At least one soluble group or latent alkali soluble
Group.

In one embodiment according to the method of the present invention,
The dye corresponds to general formula (II) and has at least one soluble
An alkyl chain containing a group corresponds to one of the following formulas:
(CH ₂)_mSO₃ ⁻Or (CH₂)_mN (R) SO₃
⁻(M is equal to 1, 2, 3 or 4 and R is R¹~ R⁴When
(Has the same meaning); (CH₂)₂CH (Y) SO₃ ⁻
(Y is CH₃-, -Cl or -OH); (CH
₂)_c OSO₃ ⁻(C is equal to 2 or 3); (CH
₂)_d CO₂ ⁻(H⁺(D is equal to 1, 2 or 3)
I); (CH₂)_sSO₂ ⁻(CH₂)_tH (S is 2 or
Is equal to 3 and t is equal to 1 or 2);-(CH₂)
_f-Phen-W (W is -COO⁻Or SO ₃ ⁻Represents
And Phen represents a phenyl group, and f is 1, 2, 3, or
Is equal to 4).

In another embodiment according to the method of the present invention, in said dyestuff corresponding to the general formula (II), the alkyl chain containing at least one latent soluble group containing an alkyl chain has the formula (CH ₂ ) _{m ′} -( _{C = O) -O-CH 2} - (C =
O) _-CH 3 (m 'is an integer having a value of 1 to 5)
Is equivalent to

In a further preferred embodiment according to the method of the invention, said dye corresponds to formula (III) or (IV):

Embedded image

Embedded image In the formula, Q, M ⁺ , n ′, R ¹ and R ² have the same meaning as described above.

In a further preferred embodiment according to the method of the present invention, said dye corresponds to formula (V):

Embedded image In the formula, R ¹ , R ² , n ′ and M ⁺ have the same meaning as described above.

In a particularly preferred embodiment according to the process according to the invention, the dyes correspond to formulas (VI) or (VII):

Embedded image

Embedded image

According to the method of the present invention, the non-J band aggregating dye versus J
The molar ratio of the band aggregation dye is 1:20 to 10: 1, more preferably 1: 5 to 5: 1, and still more preferably 1: 5 to 5.
5: 4. When expressed in mol per mol of silver, the specific dye anhydro-5,5'-dichloro-
3,3'-bis (n-sulfobutyl) -9-ethyloxacarbocyanine hydroxide or anhydro-5
5'-Dichloro-3,3'-bis (n-sulfopropyl) -9-ethyloxacarbocyanine hydroxide or a sulfopropyl derivative thereof is present in an amount of 0.1% per mole of silver.
From 20 to up to about 1 mmol is added, while the dye according to formula (VII) above is added in an amount from about 0.15 or more up to about 1.20 mmol per mole of silver. In contrast, if used alone, up to 2.8 mmol of J-band aggregating dye per mole of silver is added to obtain good spectrally sensitized tabular emulsion grains.

Particularly when the amount of JAD is decreasing, the positive effect of the increasing amount of NJAD on the absence and speed of dye stain is noticeable to a certain extent, as is clearly shown in the examples. : In a particularly preferred embodiment according to the method of the present invention, the one or more non-J band aggregating dyes are silver 1
present in a total amount of at least 0.15 mmol per mol
The above J-band aggregated dye is present in a total amount of less than 1 mmol per 1 mol of silver.

As already mentioned, the tabular silver halide emulsion used in the method of the present invention has an average aspect ratio of at least 2: 1, an average crystal diameter of 0.3 μm to 3.0 μm and an average of less than 0.50 μm. Tabular silver halide grains having a thickness of at least 50% of the total projected surface area of said grains.
% Of tabular silver halide grains.
In a preferred embodiment, the average thickness of the tabular silver halide grains is less than 0.30 μm, preferably 0.20 μm
Less than 0.06 μm. In an even more preferred embodiment said particles are at least 5: 1, more preferably 5: 1 to 20: 1, even more preferably 8: 1 to 1.
It has an average aspect ratio of 5: 1. Further, the average crystal diameter, calculated as the average equivalent circular diameter from electron microscopic data obtained from all tabular grains present (occupying at least 50% of the total projected surface area of the aforementioned grains), is more preferably from 0.3 μm to It is 2.0 μm, even more preferably 0.4 μm to 1.0 μm.

According to the method of the present invention, said halide in said silver halide tabular grains is selected from the group consisting of bromide, chloride and iodide. In the case of tabular bromo (salt) silver iodide emulsion crystals, the bromide content is preferably at least 90 mol%, more preferably at least 9 mol%.
5 mol%, more preferably at least 98 mol%
And the silver iodide content is preferably less than 2 mol%, more preferably less than 1 mol%, and still more preferably 0.2 mol%.
mol%, even more preferably 0.05 mol%
It is as follows. This prevents suppression in the development process and enables rapid processing.

In the case of tabular salt (bromo) silver iodide emulsion crystals, the chloride content is at least 90 mol%, more preferably at least 95 mol%, even more preferably at least 98 mol%, and the silver iodide content is preferably Is less than 2 mol%, more preferably less than 1 mol%, even more preferably less than 0.2 mol%, even more preferably 0.05 mol% or less. This prevents the development process from being suppressed and promotes rapid processing.

As mentioned above, it is preferred to have a low iodide content, so that the iodide is as homogeneous as possible over the entire crystal volume of the tabular crystals rich in silver bromide or over the outermost shell of the tabular crystals rich in silver chloride. Preferably, ions are formed. Silver iodide can be obtained by double jet addition of (preferably diluted) silver nitrate and potassium iodide solutions, by conversion used from (preferably diluted) potassium iodide solutions, for example EP-A 0 536 370.
8,0561415, 0562476 and 056370
From organic iodide-releasing agents as described in No. 1, more preferably, for example, EP-A 0475191 and the corresponding U
0.05μ as described in SA 5206134
It can be added by the addition of iodide ions which rapidly evolve from ultrafine (homogeneous) silver iodide Lippman emulsions having an average crystal diameter of less than m (also called "microlate emulsions").

In addition to the tabular crystals as described, the emulsions used in the process according to the invention contain a binder. An overview of binders useful in the method of the present invention is provided in Research Disclosure No.
38957, issued September 1, 1996, Chapter II. A more detailed description is given in EP Application No.
No. 96203203 (filed Nov. 15, 1996), which describes the use of various types of gelatin as commonly used hydrophilic binders in the preparation of silver bromide-rich tabular grain emulsions. , EP-A
No. 0677773, the colloidal silica is, for example, EP-A
It is described as an alternative useful binder such as the cationic starch described in EP 0758758.

The tabular silver halide emulsion prepared by the method of the present invention is described, for example, in "Chimie et Physique Photogr."
aphique ”, P. Glafkides,“ Photographic Emulsion
Chemistry ", GF Duffin," Making and Coatin
g Photographic Emulsion ”, VL Zelikman et al., and“ Die Grundlagen der Photographischen Prozessemit
Silberhalogeniden ”, edited by H. Frieser and Akademische V
Chemically sensitized as described in erlagsgesellschaft (1968). Chemical sensitization is for example Resear
ch Disclosure No. 38957 (1996), Chapter
It is also described in IV. As described in the literature, chemical sensitization can be performed by aging in the presence of compounds containing small amounts of sulfur, such as thiosulfate, thiocyanate, thiourea, sulfite, mercapto compounds, and rhodamine. it can. The sulfur-containing compound can also be at least partially replaced by a compound containing selenium and / or tellurium. Emulsions may be made with gold-sulphur, gold-selenium, gold-sulphur-selenium ripeners or with a reducer such as GB 789
Sensitization can also be achieved with tin compounds, amines, hydrazine derivatives, formamidine-sulfinic acids, and silane compounds as described in US Pat.

According to the method of the present invention, the chemical ripening of the tabular grains is carried out in the presence of a combination of sulfur, selenium and a gold ion donating compound. Such a combination is for example EP-A
0443453. A selenium compound particularly suitable for use in the method of the present invention is US-A 502
8522, 5112133, 5397692 and 564
1619, EP-A 0476345, 056607
4,085,787,0661589 and EP Application No.
97200590 (filed on March 1, 1997). Even a combination of selenium sensitization while adding a silver iodide Lippmann emulsion is described, for example, in EP-A 06388.
40 is possible. Gold compounds particularly suitable for use in the method of the invention include, for example, US-A
5376522 and 5700631. Particularly suitable sulfur compounds for use in the process of the present invention are described in US-A 5,667,957. US
Combinations with reduction sensitization as described in -A 557 901 are also possible. Provided that a suitable stabilizer or combination of stabilizers is added to the emulsion as described in US Pat. No. 5,114,838.

According to the method of the present invention, J-band and non-J-band forming spectral sensitizers are the earliest patents relating to tabular grain emulsions filed by E. Kodak in 1981, especially US Pat.
Added before the addition of the aforementioned chemical sensitizing compounds, as already disclosed in -A 44 25 425 and 44 39 520; It is not important in the method of the present invention whether a non-J-band aggregated dye or a J-band aggregated dye is added as the first dye to the tabular grain emulsion. Even mixtures of both can be made before addition to the emulsion.

According to the present invention, tabular silver halide grains having an aspect ratio of at least 2: 1, an average crystal diameter of from 0.3 μm to 3.0 μm and an average thickness of less than 0.50 μm are obtained by total projection of said grains. Provided is a light-sensitive silver halide emulsion (preferred examples have been described above) comprising tabular silver halide grains occupying at least 50% of the surface area, said grains comprising at least one J-band aggregate spectral sensitizing dye and at least one Has non-J-band aggregating dyes (these special examples have been described above).

According to the present invention, one or more non-J-band aggregating dyes are present in an amount of 0.15 mmol or more per mole of silver and one or more J-band aggregating dyes are present in an amount of 1 mm / mol of silver.
A light-sensitive silver halide emulsion is provided which is present in an amount of less than ol. More specifically, it is clear that the amount of J-band aggregation spectral sensitizing dye is always less than the amount normally (optimally) added when only one or more dyes of the same J-band aggregation type are present. Unexpected results are associated with the presence of non-J-band aggregated dyes when small amounts of J-band aggregated dyes are present,
That is, there is no sensitivity loss in addition to the desired contrast and image clarity, as well as the absence of residual dye stain after processing, even in rapid processing applications with reduced amounts of replenisher. The "robust" or "preserved" film processing system thus obtained is characterized as a single type of dye as is well known by anyone skilled in the photographic art. Less dependent on the amount of band aggregation spectral sensitizing dye (if present). The one or more non-J-band aggregated dyes compensate for the reduced amount of J-band aggregated spectral sensitizing dye.

For example, Research Disclosure (RD) No.
38957, p. Additives may be further added to the photographic emulsion of the present invention as described in 591-39 (especially with respect to stabilizers, for example, Chapter VII of RD). Suitable examples are heterocyclic nitrogen-containing compounds, such as benzothiazolium salts, nitroimidazole, nitrobenzimidazole, chlorobenzimidazole, bromobenzimidazole, mercaptothiazole, mercaptobenzothiazole, mercaptobenzimidazole, mercaptothiadiazole, aminotriazole , Benzotriazole (preferably 5-methyl-benzotriazole), nitrobenzotriazole, mercaptotriazole, mercaptotetrazole, especially 1-phenyl-5
-Mercapto-tetrazole, mercaptopyrimidine,
Mercaptotriazine, benzothiazoline-2-thione, oxazoline-thione, triazaindene, tetraazaindene and pentaazaindene, especially by Birr, Z.
Wiss. Phot. 47 (1952), pp. 2-58, GB-A 1203775 and GB.
-A 1209146, JP-A 75/39537,
And triazolopyrimidines such as those described in GB-A 1500278, and US-A 472701.
7-hydroxy-s-triazolo- as described in 7
[1,5-a] -pyrimidine and other compounds such as benzenethiosulfonic acid, benzenethiosulfinic acid and benzenethiosulfonic acid amide.

Many of these fogging inhibiting compounds may have already been added during the chemical ripening of the tabular silver halide crystals of the present invention as described above.

To establish optimal coating conditions and / or to establish the required thickness of the coated emulsion layer, additional gelatin or polymer binders are added at a later stage in the emulsion preparation.
Obviously, for example, it is added after washing. A ratio of gelatin (as the most preferred binder) to silver halide, preferably in the range of 0.3 to 1.0, is then obtained, with the extra gelatin added being the step of preparing the grains according to the method of the invention. Is not required to have a special composition.

Another binder may be added instead of or in addition to gelatin. Useful vehicles, vehicle extenders, vehicle-like additives and vehicle-related additives are described, for example, in Research Disclosure No. 38957.
(1996), Chapter II and EP-A 052847.
6 and 0831362.

The gelatin emulsions according to the invention comprising tabular grains and at least one J-band aggregating dye and at least one non-J-band aggregating dye can be used in various types of photographic materials, such as those used for X-ray diagnostic purposes. And black-and-white silver halide photographic materials.

According to the present invention there is further provided a photosensitive silver halide photographic material, preferably a radiographic material, said material comprising a support, at least one hydrophilic colloid layer on at least one side of said support. And one or more light-sensitive layers comprising a silver halide photographic emulsion according to the present invention as described above.

The gelatin binder of the photographic material having at least one gelatin emulsion according to the present invention may be any suitable hardener, for example of the epoxide type, of the ethyleneimine type, of the vinylsulfone type (eg of 1,3-vinyl Sulfonyl-2-propanol, chromium salts (eg, chromium acetate and chromium alum), aldehydes (eg, formaldehyde, glyoxal, and glutaraldehyde), N-methylol compounds (eg, dimethylolurea and methyloldimethylhydantoin), dioxane derivatives (eg, 2, 3-dihydroxy-dioxane),
Active vinyl compounds (eg, 1,3,5-triacryloyl-hexahydro-s-triazine), active halogen compounds (eg, 2,4-dichloro-6-hydroxy-s-)
Triazine), and mucohalic acids (e.g., mucochloric acid and mucophenoxychloric acid). These curing agents can be used alone or in combination. Binders can also be hardened with fast-acting hardeners such as carbamoylpyridinium salts as disclosed in US Pat. No. 4,063,952 and with onium compounds as disclosed in EP-A 0408143.

In a preferred embodiment according to the invention, the photographic material comprises a support and on one or each side thereof one or more silver halide emulsion layers coated from a gelatin emulsion according to the invention. In particular, said photographic material is a single-sided or double-sided X-ray material. The single-sided X-ray material may comprise a single emulsion layer (which applies for many applications), or it may be made by two or more emulsion layers. In radiography, a material having a single or double coated emulsion layer coated on one or both sides of the support contains at least one gelatin silver halide emulsion according to the invention. By using double coated emulsions differing in photographic speed by at least 0.15 log E, an increase in crossover exposure in double coated materials can be obtained. In the case of color photography, the material contains blue, green and red sensitive layers, each of which can be single coated or simply consist of double or triple layers. In addition to the light-sensitive emulsion layers, the photographic material may contain several light-insensitive layers, such as protective layers,
The above-mentioned backing layer, one or more undercoat layers, one or more intermediate layers,
For example, it may include a filter layer and an after layer containing, for example, a curing agent, an antistatic agent, a filter dye for safety light purposes, and the like. The photographic material of the present invention is Research Dis
closure No. 38957 (1996), Chapter IX (in which coating aids, plasticizers, lubricants, antistatic agents and matting agents are described), and may further contain various additives that change the coating physical properties. Good. The development is accelerated by various compounds, preferably, for example, US-P 3038805,40.
38075 and 4292400, and EP-A 063
This can be achieved by incorporating a polyalkylene derivative having a molecular weight of at least 400, such as those described in US Pat.

The photographic material of the present invention may further comprise various other additives such as compounds which improve the dimensional stability of the photographic material, UV absorbers, spacing agents and plasticizers. Additives suitable for improving the dimensional stability of photographic materials are:
For example, water-soluble or poorly water-soluble synthetic polymers such as polymers of alkyl (meth) acrylate, alkoxy (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, vinyl ester, acrylonitrile, olefin, and styrene, or those described above. And a copolymer of acrylic acid, methacrylic acid, α-β-unsaturated dicarboxylic acid, hydroxyalkyl (meth) acrylate, sulfoalkyl (meth) acrylate, and styrene sulfonic acid).

Suitable UV absorbers are, for example, US-P 3
Aryl-substituted benzotriazole compounds as described in US Pat. No. 5,337,794, US Pat.
No. 681, 4-thiazolidone compounds, JP-
A benzophenone compounds as described in A 2784/71, cinnamic acid ester compounds as described in U.S. Pat. Nos. 3,705,805 and 3,707,375, U.S. Pat.
229, and US-A
A benzoxazole compound as described in No. 3700455 and a suitable optical brightener are also described in RD No.
38957 (1996), Chapter VI. The spacing agent generally has an average particle size of 0.2 to 10 μm.
m can be present. Spacing agents can be soluble or insoluble in alkali.
Alkali-insoluble spacing agents usually remain permanently in the photographic material, while alkali-soluble spacing agents are usually removed therefrom in an alkaline processing bath. Suitable spacing agents can be made, for example, from polymethyl methacrylate, from copolymers of acrylic acid and methyl methacrylate, and from hydroxypropyl methylcellulose hexahydrophthalate. Other suitable spacing agents are described in U.S. Pat. No. 4,614,708.

The photographic material may comprise several light-insensitive layers, such as a stress-resistant topcoat layer, one or more backing layers, and one or more filters that absorb scattered light and thus enhance image sharpness or contain antihalation dyes. Of an intermediate layer. Suitable light-absorbing dyes for use in these intermediate layers are described, for example, in U.S. Pat.
SA 4311787, DE-A 2453217,
And GB-A 7907440. Due to the location of such an intermediate layer between the emulsion layer and the support, decolorization of the filter dye layer in rapid processing conditions forms a problem, as well as a small negligible loss in sensitivity. Therefore, it is recommended to reduce the thickness of the entire coating layer packet and shorten the drying time after cleaning in the processing cycle.

According to the present invention there is provided a radiographic screen-film combination comprising at least one X-ray intensifying screen in operation with the material according to the present invention as described above. Since the light emitted from the screen by the phosphor incorporated therein is an important source of light scattering, the addition of an appropriate filter dye to the screen is recommended. For example, in a green light emitting phosphor screen, MAKR
OLEX ORANGE G or GG, (BAYER
Certain dyes (such as AG brand products) may be used.
One or more backing layers can be provided on the non-light sensitive side of the support of a material coated with at least one emulsion layer on only one side of the support. These layers, which can act as anti-curl layers, include, for example, matting agents such as silica particles, lubricants, antistatic agents, light absorbing dyes, opacifiers (eg titanium oxide) and conventional agents such as hardeners and wetting agents. Components can be included.

The support of the photographic material can be opaque or transparent, for example a paper support or a resin support. When a paper support is used, preference is given to those coated on one or both sides with an α-olefin polymer, for example a polyethylene layer optionally containing an antihalation dye or pigment. Further, an organic resin support such as a cellulose nitrate film, a cellulose acetate film, a poly (vinyl acetal) film, a polystyrene film, a poly (ethylene terephthalate) film or a poly (ethylene naphthalate) film, a polycarbonate film, a polyvinyl chloride film, or a poly (ethylene chloride) film -Α-olefin films (for example, polyethylene or polypropylene films) can also be used. The thickness of such an organic resin film is preferably 0.07 to 0.35 mm. These organic resin supports are preferably coated with a subbing layer that can contain water-insoluble particles such as silica or titanium dioxide.

The photographic materials containing tabular grains prepared according to the present invention can be image-wise exposed by any convenient radiation source according to the particular use.

Of course, the processing conditions and the composition of the processing solution are determined by the particular type of photographic material to which the tabular grains prepared according to the present invention are applied. For example, in a preferred example of a material for X-ray diagnostic purposes, said material may be adapted to rapid processing conditions. Preferably, an automated processor is used provided with a system for automatic regeneration of the processing solution. The pre-cured material may be processed using one-part or three-part package chemicals depending on the processing application that determines the degree of cure required for the processing cycle. Applications within the overall processing time of 30 seconds and up to 90 seconds commonly known are possible. From an ecological point of view, for example, instead of hydroquinone, which is problematic as the main developing agent in the developer, partially or completely (iso)
-Ascorbic acid, reductic acid or a derivative thereof, sodium thiosulfate can be used instead of ammonium thiosulfate as a fixing agent in a fixing solution.

The present invention will be described with reference to the following examples, but the present invention is not limited thereto.

[0058]

EXAMPLES In practice, spectral sensitizing dyes are "J-band spectral sensitizing dyes" or "J-band aggregated dyes" if the dyes form J aggregates if adsorbed on the surface of silver halide grains. It is called. J aggregates are characterized by a sharp absorption band (referred to as J band) with a deep color shift with respect to the absorption maximum of the free dye in the diluted aqueous solution.

A sample of the silver halide emulsion is subjected to ultrafiltration or re-dispersion (in the case of coagulation washing), prior to chemical sensitization (removal of sulfur and / or selenium and / or tellurium compounds which are unstable during the process). (Added with the gold salt). A spectral sensitizing dye was added to this unripened (so-called "primitive") emulsion sample per mol of silver halide in the following amounts (mol): 0 (blank); 1 × 10 ⁻⁶ ; 1 × 10
⁻⁵ ; 1 × 10 ⁻⁴ ; 1 × 10 ⁻³ . The emulsion was prepared at a concentration of 60 g of silver nitrate per liter of sample at 38 ° C. for 7 hours.
0 mV UAg (potential with respect to silver / silver chloride reference electrode),
Had a pH of 5.5. Absorption spectra were taken for all samples, including the "blank" sample. If one or more absorption peaks appear by increasing the amount of spectral sensitizing dye (the absorption spectrum is "small" corresponding to a wavelength at half the total height of the peak below 40 nm)
(Showing a deep color shift with a band width), then the dye is referred to as a "J-aggregated" or "J-band aggregated" dye.

Emulsion samples of "primitive" silver bromoiodide emulsions (the preparation of which is given below) are dissolved in deionized water at 38 ° C. and the concentration is adjusted to contain about 60 g of AgNO ₃ / kg. Obtained. The pH is adjusted to a value of 5.5 and the UAg value (potential value displayed for the Ag / AgCl reference electrode)
Was adjusted to a value of 70 mV with KBr. To each sample of this unchemically ripened, unstabilized emulsion, the spectral sensitizing dye was added to the diluted solution in the amount given above per mole of silver nitrate present. After 30 minutes, the absorption spectrum was measured with a spectrophotometer (SHIMADZU).

The difference between the spectra (spectrophotometric curves in the region of 400 to 700 nm) is calculated and recorded as described above, and the presence or absence of “J-band aggregation” is detected, and the “J-band” is detected.
Aggregated dye (JAD) or "non-J band" aggregated dye (NJA
D) was determined to be present.

Example No. 1 Emulsion preparation: Three solutions were used during the precipitation: Solution 1: 1.5 liter of an aqueous solution containing 500 grams of silver nitrate (a 1.96 N solution of silver nitrate); Solution 2: 0.525 liter of an aqueous solution containing 175 grams of potassium bromide (1.96 of potassium bromide)
-Solution 3: 0.975 liter of an aqueous solution containing 320 grams of potassium bromide and 5 grams of potassium iodide (1.93N potassium bromide; 0.03N potassium iodide).

An emulsion having silver iodobromide emulsion crystals containing 1.0 mol% of silver iodide was prepared using the three solutions described above by the following manufacturing steps: nucleation and primary
Neutralization step, second neutralization step and growth step, followed by third and fourth neutralization steps, and second growth step. Precipitate is pAg or p
Uses double jet technology with continuous control of the Br value (the values are each defined as the negative logarithm of the silver or bromide ion concentration) and, where necessary, the application of continuously varying the rate of solution addition to the reaction vessel It was done.

Nucleation step: 8 ml of solutions 1 and 2
Was introduced into the reaction vessel in 30 seconds using the double jet technique. The reaction vessel initially contained 3 liters of 51 ° C. deionized water, 1.5 grams of potassium bromide and 5.5 grams of oxidized gelatin (pH adjusted to a value of 1.8; pBr). = 2.39). After 90 seconds, the reaction temperature of the mixture was increased to 70 ° C. in 25 minutes and the pH was increased to 6.0.
After 210 seconds, 500 ml of an aqueous solution of phthalated gelatin (10% by weight) was added. After another 330 second waiting time, the first neutralization step was started.

The first and second neutralization steps: 7.5 ml /
After flowing the solution 2 into the reaction vessel for 330 seconds at a speed of minutes, the second neutralization step was started. During the second neutralization step, solution 1 was flowed at a rate of 7.5 ml / min for 60 seconds, while simultaneously solution 2 was flowed into the reaction vessel at a rate to maintain a constant pAg value of 8.85. After that, growth began.

First growth step: Double jet precipitation was started using solutions 1 and 2, which lasted 33 minutes 22 seconds. During this precipitation, the rate of addition of solution 2 is continuously adjusted, while the starting rate of 7.5 ml / min (finally 23.1
The pAg value was kept constant at 8.85 by adding 510 ml of solution 1 (primary increase to ml / min). Thereafter, the third neutralization step was started.

The third and fourth neutralization steps:
Immediately after the addition at a rate of 7.5 ml / min for 0 seconds, a fourth neutralization step was performed. During the fourth neutralization step, solution 1 was flowed at a rate of 7.5 ml / min for 100 seconds while solution 2 was simultaneously flowed into the reaction vessel at a rate to maintain a constant pAg value of 7.38. Thereafter, the second growth process was started.

Second growth step: Double jet precipitation was started using solutions 1 and 2 and continued for 40 minutes 56 seconds. During this precipitation, the rate of addition of solution 2 is continuously adjusted, while the starting rate of 7.5 ml / min (3 at the end of the precipitation).
The pAg value was kept constant at 7.38 by adding 907 ml of solution 1 (primary increase to 6.8 ml / min).

After sulfuric acid was added to a pH value of 3.5, stirring was stopped, and after sedimentation, the upper layer solution was removed. After setting the scraping rubber and adding polystyrene sulfonic acid to obtain a quantitative aggregate without silver loss, the washing method was started.

During redispersion of the emulsion, 150 g of gelatin was added to give a weight ratio of gelatin to silver nitrate of 0.4. The emulsion contained an amount of silver bromoiodide equivalent to 190 g of silver nitrate per kg.

After redispersion, each example was analyzed using the intensified replica obtained by the electron microscope. A minimum of 100 grains were measured for each example and the following properties were calculated to give the properties of the crystal population of the emulsion: average thickness (t): from the distance between the major faces measured for all crystals -Percentage of total projected surface area (% PO): the percentage expressed as silver of the total projected area covered by the tabular grains;-Average equivalent volume diameter (EVD): applicable Average diameter calculated from the average volume of all grains, expressed as the diameter of a sphere having the same volume as the tabular crystal to be grown.

The emulsion grains prepared as described above had the following properties: t = 0.18 μm; O. = 95% or more; EVD =
0.75 μm.

The emulsion thus prepared was divided into four parts. Emulsion crystals are chemically ripened with sulfur and gold at 47 ° C in the presence of non-J aggregated dyes and green light absorbing J aggregated dyes as spectral sensitizing dyes for a time to obtain the optimal relationship between fog and sensitivity (speed) did. Non-J
Aggregation dye (NJAD) is absorbed by green light. J aggregation dye (JAD)
Was added later. Dye amount (mmol / silver m
ol) and the time of addition of the dye ("BCR" = before chemical ripening; "ACR" = after chemical ripening) are given in Table 1 along with the sensitometric data obtained as described below. The total amount of green light absorbing JAD was 1.26 and 0.63 mmol / mol silver in the two comparative coatings, respectively, with increasing amounts of NJAD (0.32 and 0.
0.63 mmol / mol in the two coatings of the invention with the addition of 64 mmol / mol).

The following amounts of components (different from the dyes) were added to all emulsion parts (amount added per mole of silver): 135 mg of potassium thiocyanate; 1 mg of sodium thiosulfate (5 mol / mol of crystals) Water (hereinafter referred to as "5aq"); 0.7 mg
(Containing 4 mol of water per 1 mol of crystal, hereinafter referred to as “4aq”). Emulsion coating (expressed per liter after addition of deionized water to reach a concentration corresponding to about 200 g of silver nitrate per liter of coating solution): 785 mg of 4- as antifoggant and stabilizer
Hydroxy-6-methyl-1,3,3a, 7-tetraazaindene, 2.68 g of resorcin as a hardener.

A protective coating composition was prepared containing the following components per liter in deionized water: 35.4 g of inert gelatin, 37 g of silica particles having an average diameter of 7 to 10 nm (30% by weight). An aqueous dispersion of a matting agent having a particle size diameter of 2 μm containing 20 g of 3.2% polymethyl methacrylate and 10% of gelatin, 300 mg of ammonium perfluoro as surfactant Octanoate (FC143, a trademark product from 3M) and 750 mg of N-polyoxyethylene-N-ethyl-perfluoro-octane-sulfonamide (FC
170C, trademark product from 3M), 1500 mg of phenol as preservative, 1000 mg of Mobilc from MOBIL OIL as lubricant
er Q.

Bis- (vinylsulfonyl) -methane was added as a curing agent in such an amount that the material had a swelling degree of 200% or less when the cured material was immersed in deionized water at 35 ° C. for 3 minutes.

1.1 g per square meter per side
Together with a protective layer containing gelatin and an emulsion layer having 3.5 g of silver expressed as the equivalent of silver nitrate, a solution for the emulsion coating and for the protective coating was coated on a polyethylene terephthalate film support having a thickness of 175 μm. Simultaneously coated on both sides.

Exposure, sensitometry and densitometry data: Samples of these coatings were treated at 34% RH and 57%.
"Corning filter 4010" as a filter having a density of 2.64 (measured with a Macbeth TR 924 densitometer), stored at a temperature of 3O <0> C for 3 days, transmitting green light in the range of 500-580 nm with a transmittance maximum of 525 nm. And a projection lamp (130 V) having a 90 V exposure voltage for 0.1 second at a distance of 1.8 m from the filter through a continuously changing carbon-coated wedge (wedge constant 0.15) with a density filter having a density of 0.30. ; 250 W).

The exposed samples were processed in the following 90 second cycle. The density as a function of the light dose was measured and the following parameters were determined: fog level (with a precision of 0.001 density; given number = 1000 times fog D) and 1 density above fog (Relative speed in log E (exposure)): The lower the value, the higher the speed.

Stain was visually controlled: "Yes" if the stain was still visible; "No" if there was no noticeable or disturbed stain density. Automatic processing was performed with a glutaraldehyde-containing hydroquinone / 1-phenyl-3-pyrazolidinone developer and then with an aluminum-containing fixer. These liquids are trade names G138 and G334, respectively, Agfa
-Sold by Gevaert NV.

CURIX 530 (Agfa-Gevaert NV)
Was used as an automatic processor. The CURI
The processing order and conditions in the X530 processor are as follows (expressed in seconds, with temperature (° C.) added to it): Loading: 3.4 seconds Development: 23.4 seconds / 35 ° C. Development Liquid G138 (trade name) Crossover: 3.8 seconds Fixing: 15.7 seconds / 35 ° C. Fixing liquid G334 (trade name) Crossover: 3.8 seconds Rinse: 15.7 seconds / 20 ° C. drying: 32.2 Second (including crossover time) Total time: 98.0 seconds

Table 1 summarizes the results of these experiments.

[Table 1]

From Table 1 above, it can be seen that the addition of a low amount of non-J-band aggregating dye to the tabular grain emulsion, prior to the start of chemical ripening, of a non-J-band aggregating dye (giving the absence of dye stain) was partially added. The invention sample N in that a marked increase in speed is achieved if added in amounts to compensate (see 2 and 3 for 1) or completely (see 4 for 1).
o. It is clear that 3-4 illustrates the invention, but only half of the normally added amount of JAD is Sample No. 1.
Compare the speed loss if added as in Sample No. 2.

Example No. 2 The same emulsion as in Example 1 was prepared and, after redispersion, divided into nine portions. Emulsion crystals were chemically treated with sulfur, selenium and gold in the presence of green light absorbing J-aggregated dyes and non-J-aggregated dyes as spectral sensitizing dyes at 47 ° C. for a time to obtain the optimal relationship between fog and sensitivity (speed). Aged. The order of addition of the dyes was such that the non-J aggregated dye (NJAD) was always added after the green light absorbing J aggregated dye (JAD). The amount of the dye (mg / mol of silver) and the time of addition of the dye (“B
("CR" = before chemical ripening; "ACR" = after chemical ripening) are given in Table 2 together with the sensitometric data obtained as described above.The total amount of green light absorbing J-aggregated dye added is always 1. 26 mmol / mol silver: if the total amount was not achieved by chemical ripening, an additional amount was added after chemical ripening to compensate for it.

The following amounts of components (different from dyes) were added to all emulsion parts (amount added per mole of silver): 135 mg of potassium thiocyanate; 1.7 mg of sodium thiosulfate (5 aq.); 1.2 mg of triphenyl phosphate selenide; 1.3 mg of gold chloride (4aq.).

Emulsion coating No. 5-13 was the same as Example No. 1 together with the meanings of exposure, processing and sensitometry and densitometry data.

[Table 2]

From Table 2 above, it can be seen that a significant increase in speed is achieved if the non-J-aggregated dye is added to the tabular grain emulsion after the start of chemical ripening, after the addition of the green light absorbing J-aggregated sensitizing dye. It is clear that the present invention sample No. 10-13 shows the present invention.

If the amount of non-J aggregated dye is increased,
Speed is increased without excessive fog increase. If compared with Comparative Material Sample Nos. 5-9, an optimal fog-sensitivity relationship is obtained with a significant increase in speed.

The (partial) addition of JAD after chemical ripening was carried out as in the case of material samples Nos. 10 and 11 of the present invention (comparative sample N) even though many non-J aggregated dyes were present during chemical ripening.
o leads to the same or higher speed (for 8 and 9), but leads to higher fog and lower speed when compared to the inventive samples Nos. 12 and 13, in view of achieving the optimum fog-speed relationship. And few advantages.

Example No. 3 The same emulsion as in Example No. 1 was prepared. After redispersion, the emulsion was divided into 12 parts. Emulsion crystals take 47 minutes to obtain the optimal relationship between fog and sensitivity (speed).
Chemically aged with sulfur and gold at ° C in the presence of green light absorbing J-aggregated dye and non-J-aggregated dye as spectral sensitizing dye.
The order of addition of the dyes was such that the non-J aggregated dye (NJAD) was always added after the green light absorbing J aggregated dye (JAD). Amount of dye added before chemical ripening (mg / silver mo
l) is given in Table 5 below, together with the obtained sensitometric data as described above, except for the gradation (contrast) and residual color or dye stain. Exposures in these experiments were performed only on the emulsion side of the one-sided coated material.

The following components (different from dyes) were added to all emulsion parts (amount added per mole of silver): 135 mg potassium thiocyanate; 2.3 mg sodium thiosulfate (5 aq.); 4 mg of gold chloride (4aq.).

The following coatings were added before coating the emulsion layers (see Table 3 below).

[Table 3]

The coating of the photographic material was such that only one emulsion layer and one protective layer were present on only one side of the support. Emulsion layer coating solutions were prepared by adding solutions of the compounds shown in Table 3 to the melted emulsion with stirring. The coating solution for the protective layer is given in Table 4.

After adjusting the pH to a value of 6.7, the viscosity and surface tension of the coating solution were optimized according to the conditions of the coating method. The emulsion layer and the protective layer were formed by conventional coating techniques at 175.
Coated simultaneously on one side of a primed polyester support having a thickness of μm. The silver coverage of the emulsion, expressed as equivalents of silver nitrate, was about 7 g / m ² .

The following coatings, summarized in Table 4, were added to the protective coating solution before coating the protective stress resistant layer.

[0096]

[Table 4] Table 4 in (a) is a polythioether A, a modified poly epichlorohydrin having an average chain length of about 20 monomer units, about 50% of the chloride groups -S-CH ₂ -
It has been replaced by _CHOH-CH 2 OH substituent.

Separate strips of the coated material were
Continuous exposure to white light filtered with a 535 green light filter for the same exposure time of 2 seconds.

Processing was carried out using the same automatic processor, the same developing solution and fixing solution, and the same processing time as in Examples Nos. 1 and 2.

Table 5 shows the sensitometric results in terms of sensitivity (as log E (exposure)): the lower the number, the higher the emulsion and overall contrast GG for the photographic strips coated, exposed and processed as described above. High sensitivity.
The amount of dye is given in mol / mol silver as in the previous example.

The values given in Table 5 for the total contrast GG, the tones, were measured from the characteristic curve starting from a density value of 0.25 over fog over a 1.75 density range up to 2.00. .

In addition, an assessment of the dye stain is given as a result of a visual inspection of the treated strip ("NO (none)", "SLIGHT (slightly present)" or "YE".
S (Yes) ").

From Table 5 below, in order to significantly improve dye stain, the amount of J-band aggregated dye expressed in mg per mole of silver (nitrate) should not be more than about 0.5 mmol / silver mole. It is concluded that However, this results in a loss of speed and contrast, a speed loss which is partially reduced by the addition of the non-J-band aggregating dye and unexpectedly results in an increase in contrast as is particularly desirable for mammographic applications. .

[0103]

[Table 5]

For a low amount of J-band flocculant dye added to the silver halide emulsion, the best relationship between speed and contrast is achieved without leaving a residual color (also called "dye stain"), It is thus concluded that sensitometry and image quality leads to a more robust system.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katy Els Septetrat, Morseur, Belgium 27 Inside Agfa Gewert Namloze Bennacht Chap

Claims (8)

[Claims] An average aspect ratio of at least 2: 1;
Average crystal diameter of 0.3 μm to 3.0 μm and 0.50 μm
A method for making a tabular silver halide emulsion wherein the tabular silver halide grains having an average thickness of less than 50% occupies at least 50% of the total projected surface area of said grains, said method comprising precipitating said grains, increasing spectral enhancement. A process for sensitizing said particles by adding at least one J-band agglutinated and at least one non-J-band agglomerated dye prior to chemical ripening. 2. The method according to claim 1, wherein the J-band aggregate dye has a maximum J-band absorption in a wavelength range of 500 nm or more,
The method of claim 1, wherein the radiation having a wavelength of less than 00 nm is absorbed. 3. The method according to claim 1, wherein the J-band aggregate dye is a cyanine dye, and the non-J-band aggregate dye is a merocyanine dye. 4. The method according to claim 1, wherein the at least one non-J-band aggregated dye is 1 mol of silver.
The method according to any one of claims 1 to 3, wherein the dye is present in a total amount of 0.15 mmol or more per mole, and the one or more J-band aggregated dyes are present in a total amount of less than 1 mmol per mole of silver. 5. An aspect ratio of at least 2: 1.
A light-sensitive silver halide emulsion comprising tabular grains, wherein the tabular grains having an average crystal diameter of 3 μm to 3.0 μm and an average thickness of less than 0.50 μm account for at least 50% of the total projected surface area of said grains. A light-sensitive silver halide emulsion further comprising at least one J-band aggregated dye and at least one non-J-band aggregated dye. 6. The method according to claim 1, wherein the at least one non-J-band aggregated dye is 1 mol of silver.
In an amount of 0.15 mmol or more per
The light-sensitive silver halide emulsion according to claim 5, wherein the band-aggregating dye is present in an amount of less than 1 mmol per 1 mol of silver. 7. The support, at least one hydrophilic colloid layer on at least one side of the support, and a support.
Or a photosensitive silver halide photographic X-ray material comprising at least one photosensitive layer comprising the silver halide photographic emulsion according to 6. 8. A radiographic screen-film combination comprising at least one X-ray intensifying screen in operation with the material of claim 7.