US3580724A - Light-sensitive supersensitized silver halide color photographic emulsions - Google Patents

Abstract

A SUPERSENSITIZED SILVER HALIDE EMULSION CONTAINING IN COMBINATION A SENSITIZING DYE OF THE FORMULA

2-((3-(HO3S-(CH2)N-),5-(PHENYL)BENZOXAZOLIN-2-YLIDENE)=

CH-C(-R1)=CH-),3-((-)O3S-(CH2)N-),5-(PHENYL)-

BENZOXAZOL-3-IUM

AND A SENSITIZING DYE OF THE FORMULA

2-((-N(+)(-R4)=Z-)>C-CH=C(-R3)-CH=),3-R2,5-Y1,6-Y2-BENZ-

OXAZOLINE (X(-))(M-1)

WHEREIN THE VARIOUS SYMBOLS ARE DESCRIBED IN THE CLAIMS.

Description

United States Patent "7' US. Cl. 96-124 Claims ABSTRACT OF THE DISCLOSURE A supersensitized silver halide emulsion containing in combination a sensitizing dye of the formula and a sensitizing dye of the formula N I la wherein the various symbols are described in the claims.

This invention relates to a color photographic emulsion which is supersensitized by the use of two sensitizing dyes in combination. More particularly, the invention pertains to a light-sensitive silver halide color photographic emulsion incorporated with at least one sensitizing dye of the general Formula A shown below in combination with at least one sensitizing dye of the general Formula B also shown below.

GENERAL FORMULA A GENERAL FORMULA B wherein:

R is a lower alkyl group,

R is a hydrogen atom or a lower alkyl group,

R and R are independently selected from the group consisting of a lower alkyl group and alkyl substituted by a sulfonic acid, carboxylic acid or hydroxyl group,

3,580,724 Patented May 25, 1971 alkyl group As is well known, supersensitization is a means for enhancing the spectral sensitivity of a light-sensitive photographic layer by using, in combination with the main sensitizing dye, a dye or non-dye compound different in chemical structure from said main sensitizing dye. Sensitizing dyes used for the supersensitization of photographic silver halide emulsions are required to satisfy the following requirements:

(1) They should be high in synergistic spectral sensitizing effects and have superadditivity.

(2) They should be proper in intended spectral sensitizing area and, particularly when used as light-sensitive color photographic materials, they should satisfy a spectral sensitivity area showing the best color reproductivity.

(3) They should have no detrimental interactions with any other photographic additives used, and they should maintain stable photographic characteristics even during storage of the resulting films.

(4) They should leave no color stains on films after development.

In view of such requirements as are mentioned above, it has heretofore been eifected to carry out the supersensitization in a visible spectral area by incorporating two or more sensitizing dyes in a photographic silver halide emulsion. However, there have been known few sensitizing dyes which can satisfy the abovementioned requirements.

The object of the present invention is to provide a light-sensitive silver halide color photographic emulsion supersensitized by the use of sensitizing dyes which satisfy the above-mentioned requirements and, particularly, do not bring about any deletrious effects in photographic characteristics such as fogging and desenitization even when they are present together with anionic compounds, which are gelatine-coagulants (precipitating agents) or magenta couplers.

As a result of various studies, it has been found that the above object can be accomplished by incorporating into a photographic silver halide emulsion at least one sensitizing dye of the aforesaid general Formula A in combination with at least one sensitizing dye of the aforesaid general Formula B. That is, the kind of sensitizing dyes, which are used in the known sensitization processes, have such drawbacks, in the case where lower alkyl groups have been substituted on all the nitrogen atoms of the heterocyclic rings [eg in the cases of the control dyes (12) and (13) mentioned below], that when used together with incorporated color couplers, they cause an increase of fog and a decrease of color sensitivity during storage of films to deteriorate the photographic characteristics of the films, in most cases. The combination of sensitizing dyes employed in the present invention is characterized by using, as the main dye, an oxacarbocyanine having sulfoalkyl groups substituted in the nitrogen atoms on the heterocyclic rings, as seen in the aforesaid general Formula A. It has been found that by using said combination, there are displayed such excellent photographic characteristics as are mentioned above.

Typical examples of the sensitizing dyes represented by the general Formulas A and B are enumerated below, but the sensitizing dyes usable in the present invention are by no means limited thereto.

Typical of the sensitizing dyes of the general Formula A are as follows:

(C QA Oa (CH2)4S03H CH a I (0119 50311 on2 rso3 oH-o=oH- (I! H If 2 a Ga 7/ (CH2)sSOaH (01193 03 OH(|3=OH \III CzHr G91II/ (CH2)2SO3H (01192303 Typical of the sensitizing dyes of the general Formula B are as follows:

=CH-C=CH (3H3 \N CH@ 1 l CzH5 CBHB =CHC=CH (3H3 CHs a crimson: camisol 0 S CH3 =CH-C=CH (L1H: CH3 N N bnnlsoan cmnooo =CHC=CH- N JHa \N I 9 Cali] (CHz)4SOa =OH-(IJ=CH CH3 -O CzHs N 1;] (132E: 93302 CH 0H3 =CHC=CH I C1- CH3 \N 1 9 CzHs (CH2)3S03 OH; H

-CHCH=CH e I GH3 CH3 r CzHs CH3 CH-C=CH 6 C104 CH5 I 2 CzHs CZ E CH3 CH-C=CH G CZHS glf CH3 I lzHs (CH2)2OH The distribution of the maximum color sensitization wave lengths of the present photographic silver halide emulsions is variable depending on the kind and amount of the sensitizing dyes represented by the aforesaid general formulas. These sensitizing dyes may be added to photographic silver halide emulsions after dissolving them together or individually in an organic solvent optionally miscible with water, such as methanol or ethanol. Further, these sensitizing dyes may be added to photographic silver halide emulsions at any time during the course of the preparation of the emulsions. Generally, however, it is preferable to add them immediately after the second ripening. The amount of the dyes to be added varies depending on the kind of silver halide emulsion. Ordinarily,

however, it is preferable to adopt such amounts that the total amount of the combination of the sensitizing dyes represented by the aforesaid general Formulas A and B is 3020O mg. per kg. of the silver halide emulsion. In some cases, the silver halide emulsion may be sensitized. In such a case, the amount of the sensitizing dye represented by the general Formula B is preferably 1-20% of the total amount.

Silver halide emulsions employed in the present invention are color photographic emulsions containing incorporated color couplers capable of forming magenta color dyes. Usable silver halide emulsions include silver iodobromide, silver chlorobromide, silver bromide and silver chloride emulsions. Particularly, the use of silver iodobromide emulsion is preferable. These silver halide emulsions may have been sensitized with noble metal sensitizers, sulfur sensitizers, reduction sensitizers or polyalkylene oxide type sensitizers, and may have been incorporated with such known additives as stabilizers, surface active agents, hardeners, etc.

The present invention will be illustrated below with reference to the following examples, but the examples are merely illustrative and the invention is, of course, not limited thereto.

EXAMPLE 1 To 1 kg. of a neutral, high speed sensitivity silver iodobromide emulsion containing 5 mol percent of silver iodide, immediately after completion of the second ripening according to the gold or sulfur sensitization process, were added sensitizing dyes of the general Formulas A and B, either singly or in combination, in the form of 0.1% methanol solutions in the amounts as set forth in Table 1.

After completion of the ripening, to the mixture was added 300 mg. of 4-hydroxy-6-methyl-1,3,3a-7-tetrazaindene as a stabilizer and was then dispersed and mixed according to an ordinary procedure with 1-(4-phenoxy-3- sulfophenyl)-3-heptadecyl-5-pyazolone as a color coupler, and the mixture was adjusted to pH 6.8 to prepare a green light-sensitive color photographic emulsion.

The thus obtained emulsion was uniformly coated on a cellulose triacetate film support and was then dried to prepare a sample. The sample was exposed to 160 Lux daylight (5400 K.) through a green filter having a maximum transmission of 525 m from a Model KS-l sensitometer (manufactured by Konishiroku Photo Industry Co., Ltd., Japan) and was then subjected to color development at 20 C. for minutes, using a color developer of the following composition:

G. N,N-diethyl-p-phenylenediamine sulfate 2.5 Anhydrous sodium sulfite 2.0 Sodium carbonate (monohydrate) 82.0 Potassium bromide 2.0

Water to make 1 1.

After the development, the sample was subjected to ordinary bleaching, fixing and water-washing treatments, and was measured in fog and green light sensitivity to obtain the results as shown in Table 1. The sensitivity value in the table is represented by the relative green light sensitivity of the sample as measured by assuming that the green light sensitivity attained by the independent use of the dye (3) is 100.

TABLE 1 sensitizing dye (0.1% methanol solution, 00.] kg. emulsion) Relative Sensi- Sensitizmg sensitizing speed for tivity dye exemplidye exempligreen maximum fiedby (3),ce. fied by (8), cc. Fog light (my) The thus prepared emulsions were immediately coated individually on the cellulose triacetate film support and were then dried to prepare fresh samples. Separately, the emulsions were incubated at 40 C. for 3 hours and then treated in the same manner as above to prepare other samples. These samples were exposed and color developed in the same manner as in Example 1 and were then subjected to sensitometry to obtain the results set forth in Table 2.

The sensitivity value in the table represents the relative sensitivity of each sample as measured by assuming that the green light sensitivity of the fresh control sample is 100.

TABLE 2 Ineubated at 40 C. for

Immediately after the 3 hours after the preparation of emulsion preparation Relative Relative green light green light sensitizing dye (0.1% methanol solution, ce./kg. emulsion) sensitivity Fog sensitivity Fog Dye exemplified by (1): Dye exemplified by (5):

40 00 3 cc 0. 07 0. 08 60 0e 5 cc 0. 12 120 0. 13

Dye exemplified by (2) Dye exemplified by (5):

10 ee 3 cc 120 0. 08 125 0. 08 60 cc 50c; 0. 13 0. 14

Dye exemplified by (2): Dye exemplified by (11):

40 cc cc 125 0. 08 130 0. 09 60 cc 5 cc 135 0. 15 130 0. 17

Control dye (14): 60 cc Control dye (15): 5 cc 100 0. 21 94 0. 28

As shown in Table 1, it is clear that if the dyes are used in combination in accordance with the present invention, the green light sensitivity is greatly enhanced as compared with the case where they are used independently.

EXAMPLE 2 The same high speed silver iodobromide emulsion as in Example 1 was divided into several portions. To each portion of the emulsion, 0.1% methanol solutions of combinations of the present sensitizing dyes represented by the aforesaid general Formulas A and B were individ- EXAMPLE 3 The same high speed silver iodobromide emulsion as in Example 1 was divided into several portions. To each 5 portion of the emulsion, combinations of 0.1% methanol solutions of the present sensitizing dyes represented by the general Formulas A and B were individually added in amounts shown in the Table 3 per kg. of the emulsion.

On the other hand, l-(2,4,6-trichlorophenyl)-3-[3- (2,4- di tert.-amyl-phenxyacetamide) benzamide1-5-pyrazolone was dissolved by heating in a mixture of di-n-butyl phthalate and ethyl acetate, and was dispersed in a gelatine solution with the use of sodium alkylbenzenesulfonate. The thus formed dispersion was added to each emulsion. Subsequently, the mixture was adjusted to pH 6.8 to prepare a green light-sensitive emulsion. Separately, the dyes (l4) and (15 employed in Example 2 were treated in the same manner as above to prepare a control emul- SlOIl.

The thus prepared samples were immediately coated individually on a film base and were then dried to prepare samples. The samples -were exposed in the same manner as in Example 1 and were color developed at 21 C. for 10 minutes the use of a color developer of the following composition:

N-ethyl-N-B-methanesulfonamidoethyl-3-methylaminoaniline sulfate2.5 g.

Anhydrous sodium sulfite-2.0 g.

Benzy alcohol-18 ml.

Sodium hexamethaphosphate--2.0 g.

Sodium carbonate (monohydrate)-5 0.0 g.

Potassium bromide-1.0 g.

Caustic soda-06 g.

Water to make-l 1.

-After the development, the samples were subjected to ordinary bleaching, fixing and water-washing treatments, and were measured in fog and green light-sensitivity to obtain the results shown in Table 3. The sensitivity value in the table represents the relative sensitivity of each sample as measured by assuming that the green light sensitivity of a combination of the control dyes is 100.

8 a second ripening according to a goldor sulfur-sensitization method. Immediately before completion of the ripening, the emulsion was divided into several portions. To each portion of the emulsion, 0.1% methanol solutions of the present sensitizing dyes represented by the general Formulas A and B were individually added in the amounts shown in Table 4 per kg. of the emulsion. After completion of the ripening, each mixture was charged with an optimum amount of a stabilizer and was then mixed according to a known procedure with 1 (3-carboxyphenyl) 3 (4-stearoylaminophenyl)-5-pyrazolone as a magenta coupler, and the mixture was adjusted to pH 6.8 to prepare a green light-sensitive, reversal color photographic emulsion. The thus obtained emulsions were uniformly coated individually on a cellulose triacetate film support to prepare samples. Further, there were also prepared stored samples in such a manner that the samples were individually stored for 3 hours at a temperature of 55 C. and for 3 days at a temperature of 50 C. and

a humidity of 50%.

Subsequently, the samples were exposed in the same manner as in Example 1 and were developed at 20 C. for 10 minutes with a developer of the following composition:

v G. Monomethyl-p-aminophenol sulfate 3 Anhydrous sodium sulfite 50 Hydroquinone 6 Sodium carbonate (monohydrate) 50 Potassium bromide 1 Water to make 1 1.

TABLE 3 Relative green light sensitizing dye (0.1% methanol solution, cc./kg. emulsion) sensitivity Fog Dye exemplified by (3): Dye exemplified by (12):

cc 2.5 cc- 130 0. 10 50 cc 120 0. l2

Dye exemplified by (1): Dye exemplified by (9):

50 cc 2. cc 125 0.07 50 cc 140 0. 08

Control dye (14):

50 cc 95 0. 1s 50 cc 100 0.20

From Table 3, it is seen that even in the presence of G lipophilic internal couplers, the photographic silver halide N,N-diethyl-p-phenylenediamine sulfate 5 emulsions in accordance with the present invention have Anhydrous sodium sulfite 2 excellent green light sensitivity less in fog as Compared Sodium carbonate (monohydrate) 82 with the conventional emulsion. P t i b id 1 EXAMPLE 4 Reversal color photographic silver iodobromide emulsion containing 3 mol percent of silver iodide which had been treated with a gelatine coagulant (sodium naphtha- Water to make 1 1.

lene-sulfonate-formaldehyde condensate) was subjected to dried.

The thus treated samples were measured in sensitivity and fog (residual color density) to obtain the results shown in Table 4. The sensitivity value in the table is the relative sensitivity of each sample as measured by assuming that the green light sensitivity of the control sample is 100.

TABLE 4 Ineubated samples Ineubated at 55 C. Ineubated at; 50 C.

for 3 days and 80% relative Fresh sample humidity for 3 days Relative Relative Relative green light green light green light sensitizing dye (0.1% methanol solution, (xx/kg. emulsion) sensitivity Fog l sensitivity Fog 1 sensitivity Fog 1 Dye exemplified by (3), 60 (20-. Dye exemplified by (7), 3 cc 140 0. 14 135 0. 15 135 0. 15

Dye exemplified by (3), 130 cc Dye exemplified by (5) 9 cc 155 0. 16 150 0.17 145 0.16

Dye exemplified by (l), 130 cc. Dye exemplified by (10), 9 cc 125 0. 13 120 O. 14 115 0. 13

Control dye (14), 130 cc Control dye (15), 9 cc 100 0. 21 90 0. 22 75 0.21

1 Residual color density.

As is clear from Table 4 the light-sensitive photographic silver halide emulsions of the present invention are high in green light sensitivity of magenta coupler layer and less in residual color density as compared with the control sample [control dye (14) control dye (15)] and that they are not decreased in color sensitivity even when subjected to severe storage tests.

What we claim is:

1. A light-sensitive silver halide color photographic emulsion which contains at least one sensitizing dye of the general 'Formula A shown below in combination with at least one sensitizing dye of the general Formula B shown below:

C=CHC=CHC a R is a lower alkyl group,

Y is a hydrogen atom or a methyl group with the proviso that Y is a methyl group when Y is a chlorine atom, or

Y and Y may form a benzene ring,

Z is a group necessary to form a thiazole, thiazoline, benzothiazole or benzoselenazole ring, or an alkyl or alkoxy derivative thereof,

X is an acid anion,

n is an integer of 2 to 4, and

m is l or 2.

2. A light-sensitive silver halide color photographic emulsion as claimed in claim 1, further containing a magenta color coupler.

3 A light-sensitive silver halide color photographic emulsion as claimed in claim 1, wherein said emulsion has been sensitized by way of noble metal sensitizers, sulfur sensitizers, reduction sensitizers or polyalkylene oxide type sensitizers.

4. A light-sensitive silver halide color photographic emulsion as claimed in claim 1, further including stabilizers, surface active agents, coating aids or hardeners.

5. -A light-sensitive silver halide color photographic element which comprises a film support and, coated thereon, a layer of the emulsion as claimed in claim 1.

References Cited UNITED STATES PATENTS 2,680,686 6/1954 Van Dormael et al. 96-104 J. TRAVIS BROWN, Primary Examiner