US3674499A

US3674499A - Silver halide photographic supersensitized emulsion

Info

Publication number: US3674499A
Application number: US41092A
Authority: US
Inventors: Keisuke Shiba; Masanao Hinata; Nobuo Tusji; Takushi Miyazaki; Akira Sato
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1969-05-27
Filing date: 1970-05-27
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04
Also published as: DE2026091B2; FR2092173A5; GB1310760A; BE750997A; CA934595A; DE2026091C3; DE2026091A1; JPS4925500B1

Abstract

A SUPERSENSITIZING COMBINATION FOR USE IN A PHOTOGRAPHIC EMULSION COMPRISING (1) A SENSITIZING DYE HAVING THE GENERAL FORMULA

GENERAL FORMULA I

Q<(-C(=C(-R4)-(C(-R5)=CH)N4-C<(-Y1-N(+)(-R2)(X(-))=(CH-CH)

N3=)(M-1))-N(-R)-CO-C(=(C(-R3)-CH)N2=C<(-Y-N(-R1)-(CH=

CH)N1-))-)

WHEREIN THE SYMBOLS R, R1, R2, R3, R4, R5, X, Y, Y1, Q, N1, N2, N3, N4 AND M ARE DESCRIBED HEREINAFTER, AND (2) A CONDENSATE OF FORMALIN WITH A HALOGENATED POLYHYDROXY BENZENE OR A HALOGENATED CRESOL, IS DISCLOSED.

Description

r' 3,674,499 Ice Patented July 1972 United States Patent 3 674 499 In this general formula, R and R are each respectively alkyl groups, such as methyl, ethyl, and propyl groups; SILVER SUPER substituted alkyl groups such as B-hydroxyethyl, B-acetoxy- Keisuke Shiba, Masanao Hinata, Nobuo Tusji, Takushi ethyl YP PY fl'sulfatoethyl 2 4 3 'Y' Miyazaki, and Akira Sato, Kanagawa, Japan, assignors 5 Sulfatopropyl 3 6 3- carboxymethyl, fiyto Fuji Photo Film, Ltd., Nakanuma, Minami Ashigara e hyl, 2-(2-Carboxyethoxy)ethyl, B-ulfoethyl, 'y-sulfopro- Machi, Ashigara-Kamigun, Kanagawa, Japan pyl, a-sulfobutyl, 2-hydroxy l-sulfopropyl, 2-(3-sulfopro- N0 P ns-fi M y 1970, 41,092 poxy) ethyl, 2-acetoxy-l-sulfopropyl, 3-methoxy-2-(3-sul- Claims priority, app llg zlf iggp y 1969 fopropoxy)-propyl, 2-2-(3-sulfopropoxy)ethoxyethyl, and Int Cl i 1/10 10 2-hydroxy-3-(3'-sulfopropoxy)-propyl; allyl groups; aryl Us. Cl. 96 123 27 Claims groups; substituted aryl groups, such as p-carboxyphenyl, p-sulfophenyl; and aralkyl groups; R is an alkyl group, a

ABS OF THE DISCLOSURE substituted alkyl group, such as a hydroxyalkyl group, a

carboxyalkyl group, a sulfoalkyl group, and the like, or an allyl group; R is a hydrogen atom, an alkyl group or an aryl group; R is a hydrogen atom, an alkyl group, such as methyl or ethyl group; or a substituted alkyl group General Formula I such as a ,8 ethoxyethyl or a 3-('y-sulfopropoxy)-ethyl A supersensitizing combination for use in a photograph- 1 ic emulsion comprising (1) a sensitizing dye having the general formula Q wherein the symbols R, R R R R R X, Y, Y Q, group, and when n,,, is 0, R may be connected through the n n n n,, and m are described hereinafter, and -(2) a methine chain with a nitrogen atom in a heterocyclic ring condensate of formalin with a halogenated polyhydroxy completed by Y R is a hydrogen atom, an alkoxy group, benzene or a halogenated cresol, is disclosed. such as a methoxy or an ethoxy group; or a substituted alkoxy group, such as a 'ysulfopropoxy or a ,B-methoxy- BACKGROUND OF THE INVENTION 30 ethoxy group; n n and n,,, are respectively 0 or 1, n is 0, or 2, Q 15 an oxygen atom, a sulfur atom or NR (1) Field of the invention 'wherein R is an alkyl group such as a methyl or an ethyl This invention relates to a silver halide photographic groupi Y and Y1 each represent for example emulsion More particularly, it is concerned with a metallic atoms necessary to complete a heterocyclic nucleus of the thiazole series for exam le, thiazole, 4-methcalled supersensitlzed silver halide photographic emulsion. y lthiazo e 4 phenylthiazolg, s methl;lthiazole, Smhenyp (2) Descnptlon of the Pnor art thiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, or 4- It i ll known th t th dditi f a i i i d (2-thienyl)thiazole), of the benzthiazole series (for examto a silver halide emulsion making a photographic ple, benzthiazole, 4-chlorobenzthiazole, S-chlorobenzthiaemulsion optically sensitizes the silver halide emulsion and 40 Z016, 5-chlol'obenlthlal0le, 7-0h10I0beI1ZthiaZ01e, enlarges its ensitive spectral region, ylbenzthiazole, 5 methylbenzthiazole, 6-methylbenzthia- When a sensitizing dye and a compound which does not Z016, 5-bromobenzthialole, G-bIOmObBIIZthiaZOIC, -P sensitize the same spectral region as the sensitizing dye Ylbenzthiazole, 5-phellylbellzthiazole, 4-methoxybenzthia' are added to a silver halide emulsion, at least a part of the Z016, 5 methoxybenzthiazole, 6-1T1eth0XybenZthiaZ31e,

spectral region which the sensitizing dye sensitizes someiodobefllthiazole, 5 ifJdobenzthiazole, 4-etholfybenzthia' times is sensitized more strongly than when the sensitizing Z916, 5 ethoxybtfiflzthlalole, ttTahYdf0benZth1aZ01'-?, dye alone is added in the same amount to the silver halide dlmethcxy-benzthlalole, 5,6-dloxymethylenebenZthlaZOle,

emulsion. In this case, the silver halide emulsion may be 5-hydfoxybenlfllialole, 0f 6-hydf0Xybe11ZthiflZ01e), 0f the considered to be supersensitized. Such compounds which naphthothiazole Series p vl-naphthoflliazole, 1 do not sensitize the same spectral reigon as sensitizing p h hi y-fi- P Y- dyes are called supersensitizers. -hnaphthothiazfi tl, I2:-meihoxy-e-r;1aphthothiazole or 7- met oxy a-nap ot iazo e), of t e benzoxazole series SUMMARY OF THE INVENTION (for example, benzoxazole, 5-chlorobenzoxazole, S-meth- It has been found that supersensitization is obtained by ylbenzoxazole, 5 phenylbenzoxazole, 6-methylbenzoxaadding to a silver halide photographic emulsion a sensizole, 5,6 dimethylbenzoxazole, 4,6-dimethylbenzoxazole, tizing dye represented by the following general Formula I S-methoxybenzoxazole, S-ethoxybenzoxazole, 6-methoxyin combination with a halogenated polyhydroxybenzenebenzoxazole, S-hydroxybenzoxazole or fi-hydroxybenzoxaformalin condensate or a halogenated cresol-formalin zole), of the naphthoxazole series (for example, a-naphcondensate. The term halogenated polyhydroxybenzene thoxazole or B naphthoxazole), of the selenazole series means a halogen-Substituted benzene having from one to (for example, 4-methylselenazole or 4-phenylselenazo'le), three hydroxyl groups in the benzene n cle s. Fur h of the benzselenazole series (for example, benzoselenazole, the tfir H1 halogenated Polyhydroxybenzene'formalin c011- S-chlorobenzselenazole, 5 methoxybenzselenazole, S-hydensate 0f halogenated cfesol-fol'malin condensate Will droxybenzselenazole, or tetrahydrobenzselenazole), of the hereinafter be referred to 38 formalin condensate. naphthoselenazole eries (for example -naphthoselena General Formula I zole or fl-naphthoselenazole), of the thiazoline series (for Y-"-- R3 R4 R5 --Y example, thiazoline or 4-methylthiazoline), of the Z-quinoline series (for example, quinoline, 3-methylquinoline, 5- methylquinoline, 7-methylquinoline, S-methylquinoline, 6- chloroquinoline, 8 chloroquinoline, 6-methoxyquinoline, G-ethoxyquinoline, 6-hydroxyquinoline or 8-hydroxyquinoline), of the 4-quinoline series (for example, quinoline, 6-methoxyquinoline, 7-methylquinoline or S-methylquinoline), of the l-isoquinoline series (for example, isoquinoline series (for example, isoquinoline itself), of the benzimidazole series (for example, 1,3-diethylbenzimidazole 0r l-ethyl-3-phenylbenzimidazole), of the 3,3-dialkylindolenine seires (for example, 3,3-dimethylindolenine, 3,3, S-tri-methylindolenine, or 3,3,7-trimethylindo1enine) or of the pyridine series (for example, pyridine or S-methylpyridine), X is an anion used in the sensitizing dye, such as a halogen ion, perchlorate, thiocyanate, p-toluene-sulfonate, benzenesulfonate, ethylsulfate, methylsulfate, and the like, and m is 1 or 2, m being 1 where an intramolecular salt is formed.

The halogenated polyhydroxybenzene used in the invention is represented by the following general formula (Xrh wherein n ranges from 1 to 3, n ranges from 1 to 3 wherein simultaneously n and n cannot both be 3, wherein X is achlorine or bromine atom.

Examples of the compounds represented by the above mentioned general formula are o-chlorophenol, m-chlorophenol, p-chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, 2,4-dichloropheuol, 2,6-dichlorophenol, 2, S-dichlorophenol, 2,4-dibromophenol, 2,5-dibromophenol, 2 chlorohydroquinone, 4-chlororesorcinol, 4-chlorocatechol, Z-bromohydroquinone, 4-bromores0rcinol, 4-bromoresorcinol, 4-bromocatechol, and 2,4,5-trichlorophenol.

The halogenated cresol used in the invention is represented by the following general formula.

wherein X, is a chlorine or bromine atom.

Examples of compounds represented by the above mentioned general formula are -chloro-m-cresol, p-chloro-ocresol and p-chloro-m-cresol.

Synthesis of the condensate of the halogenated polyhydroxybenzene and formalin can be carried out according to the concentional synthesis method for a phenolformaldehyde resin of the novolak type. The general synthesis method is as follows: The halogenated polyhydroxybenzene is dissolved or dispersed in water, to which a mineral acid, such as concentrated hydrochloric acid or sulfuric acid, and 37% formalin (aqueous solution of formaldehyde) are added, and the mixture is heated at C. for from 30 minutes to 1 hour with agitation. The reaction can be carried out under a pressure in an autoclave. After the reaction, the product is poured in cold water and the resultant precipitate is purified.

Another example is as follows: 400 parts of o-chlorophenol is dispersed in 1,000 parts of water with vigorous agitation, to which 25 parts of 35% hydrochloric acid and 250 parts of 37% formalin are then added. Then, the reaction mixture is heated at 100 C. with stirring and held for 30 minutes. 20 parts of concentrated hydrochloric acid is added additionally and the reaction is further continued for another 30 minutes. 20 parts of concentrated hydrochloric acid is then added and stirred to give a white turbidity. After about 1 hour and 30 minutes, the stirring is stopped and the mixture is transferred into 3,000 parts of cold water with agitation. The resulting precipitate is filtered, not dried, re-dissolved in 500 parts of methanol and precipitated again with cold water. Then, the precipitate is filtered and dried to obtain the desired product.

Other formalin condensates can be obtained readily in a similar manner or in the somewhat varied manner. However, the preparation of the formalin condensate used in the invention is not limited to the above described method, but can be carried out using other suitable methods.

The formalin condensate used in the invention has a condensation unit (degree of polymerization) of from 2 to 10 similar to the conventional novolak resins. For the purposes of the invention, a degree of polymerization of from 2 to 10, preferably from 2 to 5, as well as a molecular weight of from 250 to 750 is desired.

Examples of the sensitizing dye of the invention represented by the foregoing general Formula I are given in the following without limiting the invention.

G H-C H-C 0 The sensitizing dye used in the invention may be synthesized in known manner per se such as the method as disclosed in US. Pat. 2,947,680. Several synthetic examples are as follows:

SYNTHETIC EXAMPLE 1 Synthesis of I-3 4.2 g. of 3-ethyl-5 [3 ethyl naphtho[2,1-d]thiazolylidine] 1 phenylethylidene] rhodanine and 2.0 g. of methyl p-toluenesulfonate are reacted by heating at 140 C. for 2 hours. To the reaction product is added a reaction product obtained by reacting 2 g. of 3-ethyl-2-acetylmethylenebenzothiazoline and 2.3 g. of B-methoxyethyl ptoluene-sulfonate by heating at 145 C. for 3 hours, and reacted in 80 ml. of ethanol and 4 ml. of triethylamine by heating and refluxing on a warm water bath for 2 hours. After the reaction, the reaction solution is concentrated and added to an aqueous solution of sodium bromide. The precipitated crystal is washed with water, dried, treated with ethyl acetate to remove the soluble materials and then recrystallized from ethanol to obtain 1.2 g. of L3 melting at 212 C.

AER 673 my.

SYNTHETIC EXAMPLE 2 Synthesis of I-5 5 g. of 3-aryl-5-[(1-ethyl-4-quinolinidene)-ethylidene] rhodanine and 4 g. of methyl p-toluenesulfonate are reacted by heating at 110 C. for 1 hour. 3 g. of 3-ethyl-2 -ethoxypropyl)benzothiazolium p-toluene sulfonate added to the reaction product and reacted in 200 ml. of ethanol and 3 ml. of triethylamine by heating on a warm water bath for 1 hour. During the reaction, crystals are deposited and are filtered subsequently. The resulting crystal is recrystallized from methanol to thus obtam 4 g. of I-5 melting at 270 C.

MBOH max.

ing dye is incorporated in an emulsion. Some of the sensitizing dyes represented by the general Formula I, incorporated in a photographic material, cause sensitivity lowering on storage, but this disadvantage can favorably be overcome by the incorporation of the formalin condensate of the invention in combination.

The sensitizing dye of the invention is ordinarily used in a silver halide emulsion at a concentration of from 0.002 to 0.2 g./silver halide g. mol and the formalin condensate is used at a concentration of from 0.1 to 5.0 g./silver halide g. mol, the concentration ratio of the sensitizing dye and formalin condensate preferably ranging from 1:5 to 1:500. Addition of the sensitizing dye can be carried out using methods known to those skilled in the art. For example, the formalin condensate can be added to a silver halide emulsion in the form of a solution in an organic solvent such as methanol or ethanol. The sensitizing dye and formalin condensate are preferably added to an emulsion before the application of the emulsion. The order of addition to the emulsion is not limited particularly. Any of the sensitizing dyes and the formalin condensate can be added firstly or the both can be added in admixture. Furthermore, they can be added to an emulsion after water washing and during ageing.

In the invention, a conventional gelatino-silver halide emulsion is used but other resinous materials and cellulose derivatives, compatible with photographic materials, can be used of course. Silver halides such as silver chloride, silver bromide, silver iodobromide, silver chlorobromide or silver chloriodobromide, can be used for the emulsion of the invention.

The emulsion of the invention also can contain conventional additives such as chemical sensitizers, fog inhibitors, stabilizers, hardeners, coating aids, plasticizers, development accelerators, color tone regulators, whitening agents and couplers. The emulsion can be applied in the conventional manner to a suitable support such as a glass sheet, a cellulose derivative film, a synthetic resin film or a baryta paper.

The following examples are to illustrate the invention further without limiting it.

EXAMPLES (1) The sensitizing dye represented by the general F ormula I and (2) the sensitizing dye represented by the general Formula I and a formalin condensate were respectively added to different portions of the same batch of a silver halide emulsion and coated onto cellulose acetate bases followed by drying, exposing through a Fuji K Filter-7 (made by Fuji Photo Film Co.) transmitting wavelengths longer than 590 millimicrons and developing. The results 1 1 obtained are shown in Table 1 below in which the sensitivity means the value of the exposure quantity necessary for giving a fog and optical density of 0.1, based on a sensitivity of 100 in the case of incorporating the sensitizing dye only. There was no or little sensitization in the case of incorporating the formalin condensate only (not shown). In each example for comparison the same batch of the emulsion is used, but in other examples several dilferent emulsions are used. In Examples 1 to 8, the same batch of the silver chlorobromide (Br 40 mol percent, CI 10 60 mol percent) was used, in Examples 9 to 16 the same batch of silver chlorobromide (Br 50 mol percent, Cl 50 mol percent) was used and in Examples 17 to 19 the same batch of silver iodobromide (I-5 mol percent, Br 95 mol Potassium bromide Water to 1000 ml.

What is claimed is:

A silver halide photographic emulsion containing the combination of 1) at least one sensitizing dye having the following general formula wherein Y and Y each represents the non-metallic atoms necessary to complete a heterocyclic nucleus selected from the group consisting of the thiazole series, of the benzthiazole series, of the naphthopercent) was used. The development is carried out at 20 20 thiazole series, of the oxazole series, of the benzoxa- C. for 2 mnutes with a developer as shown in Table 2 zole series, of the napthoxazole series, of the thiazofor Examples 1 to 16 and at 20 C. for 4 minutes with a line series, of the Z-quinoline series, of the 4-quinodeveloper as shown in Table 3 for Examples 17 to 19. line series of the benzimidazole series, of the 3,3-di- TABLE 1 Sensi- Addltives (mg/silver halide g. mol) tivlty Fog (a) I-7 (69.0) 100 0.19 (b) I-7 (69.0) plus o-chlorophenol -formaldehyde condensate (1,460) 315 0. 08 (e) I-7 (69.0) plus pchlorophenol-formaldehyde condensate (1,460) 675 0.07 (d)I-7 (69.0) plus p-bromophenol-formaldehyde condensate (1,460)..- 398 0. 08 1 (e) I-67 (69.0) plus 2, 4-diohlorophenol-iormaldehyde condensate 251 0. 08 (f) I'7 (69.0) plus 2'0hlorohydroquinone-iormaldehyde condensate 225 0. 10 (g) l-7 (69.0) plus 4-chlororesorclnol-iormaldehyde condensate 280 0. l (l1) l1%7))(69.0) plus fi-chloro-m-crestil-formaldehyde condensate 225 0. 08 2 .----{(i) I-1 (53.0) 100 0.09 G) Ll (53.5) plus p-ehlorophenol-tormaldehyde condensate (2,920) 178 0.05 3 {(k) I-2 (78.5) 100 0.06 (1) 1-2 (78.5) plus p-ehlorophenol-iormaldehyde condensate (2,920) 145 0.06 4.----. (m) I-3 (76.3) 100 0.06 5 (n) 1:43 (76.3) plus p-ehlorophenol-formaldehyde condensate (2,920) 383 1 (p) 14 (55.7) plus p-chlorophenoltormaldehyde condensate (2,920) 478 0.05 6 q) I-5 71. l 100 0. 17 (r) I-B (71.7) plus p-chlorophenol-formaldehyde condensate (2,920) 615 0. 05 7 (s) I-6 (71. 100 0. 16 (t) I-6 (71.5) plus p-chlorophenol-iormaldehyde condensate (2,920) 316 0. 05 8 (u) I7 (69.0) 100 0. 19 (v) I-7 (69.0) plus p-chlorophenol-formaldehyde condensate (2,920) 708 0.08 9 (w) I-8 (68. 100 0.13 (x) I-8 (68.6) plus p-bromophanal-formaldehyde condensate (1,460) 210 0.09 10---- {(y) I-9 (69.7) 100 0.07 (z) I-9 (69.7) plus p-bromophenol-iormaldehyde condensate (l,460) 250 0.07 11 (a I-10 (57.1) 100 0. (b I-10 (57.1) plus p-bromophenol-formaldehyde condensate 603 0. 06

0. 07 01 11531 (55.1) plus p-bromophenol-iormaldehyde condensate 0. 07 13.- {(e I-12'(50.a)- 100 0.08 I-12 (66.5) plus p-bromophenol-formaldehyde condensate (1,460). 0. ()8 (g I-13 (69.3) 100 0.08 (h 13 (69.3) plus pbromophenol-formaldehyde condensate 190 0. 08 1a.--- {0 I-14 104.3) 100 0. 08 (j I14 (64.3) plus p-bromophenol-formaldehyde condensate (1,460)- 398 0. 06 16 {(k I-15 (73.9) 100 0 09 (l [-16 (73.9) plus p-bromophenol-icrmaldehyde condensate (1,460)- 178 0. 07 17 (111 I-16 (60.3) 100 0 09 (n2; (60.3) plus o-chlorophenol-ionnaldehyde condensate 310 0.06 18 (0 14711110.. 100 0. 25 (p I-17 (77.5) plus o-ehlorophenol-iormaldehyde condensate 251 0. 07

19 {(q I18 (69.4) 100 0. 1e (r I-18 (69.4) plus o-ehlorophenol-tormaldehyde condensate (2,920). 0. 06

TABLE 2 G, 65 N-methyl-p-aminophenosulfate 3.1 Sodium sulfite 45 Hydroquinone 12 Sodium carbonate (anhydrous) 67.5 Potassium bromide 1.9 70 Water to 1000 ml.

TABLE 3 G. N-methyl-p-aminophenosulfate 2.2 Sodium sulfite 96 75 alkylindolenine series, and of the pyridine series; wherein R and R each is selected from the group consisting of an alkyl group and, a hydroxy-, acetoxy, sulfato-, carboxy-, carboxyalkoxy-, sulfo-, hydroXy-sulfo-, sulfoalkoxy-, alkoxy-sulfoa1koxy-, sulfoalkoxy-alkoxy-, or hydroxy-sulfoalkoxy-substituted aryl group or aralkyl group; wherein R is selected from the group consisting of an alkyl group, a hydroxy-, carboxy-, or sulfo-substituted alkyl group, and an allyl group; wherein R is selected from the group consisting of a hydrogen atom, an alkyl group and, a sulfoalkoxy-, or alkoxy-substituted alkyl group and, when n; is 0, R may be connected through the methine chain with a nitrogen atom in the heterocyclic nucleus completed by Y wherein R is selected from the group consisting of a hydrogen atom, an alkoxy group and a sulfo-, or alkoxy-substituted alkoxy group; wherein n I1 and n each is or 1; wherein n is 0, 1 or 2; wherein Q is selected from the group consisting of an oxygen atom, a sulfur atom, and a =NR group, wherein R is an alkyl group, X is a negatively charged anion, and wherein m is 1 or 2, and wherein m is 1 an intramolecular salt is formed; and

(2) at least one condensate of formaldehyde with a member selected from the group consisting of a halogenated polyhydroxybenzene having the following general Formula II and a halogenated cresol having the following general Formula III X CH wherein n is 1, 2 or 3; wherein n is 1, 2 or 3 and wherein n and n are not simultaneously 3, and wherein X is selected from the group consisting of a chlorine atom and a bromine atom, are incorporated in combination. 2. The emulsion of claim 1, wherein the sensitizing dye is a compound selected from the group consisting of CHCH=CS (CHzhOCzH and Q CH CH C S S 8 0:5 am i I C2H5 N (J2EE lzHa 3. The emulsion of claim 1, wherein said halogenated polyhydrozybenzene is selected from the group consisting of o-chlorophenol, m-chlorophenol, p-chlorophenol, o-bromophenol, m-bromophenol, p-bromophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, 2,5-dichlorophenol, 2,4-dibromophenol, 2,5-dibromophenol, 2-chlorohydroquinone, 4-chlororesorcinol, 4-chlorocatechol, 2-bromohydroquinone, 4-bromoresorcinol, 4-bromocatechol, and 2,4,5-trichlorophenol.

4. The emulsion of claim 1, wherein said halogenated cresol is selected from the group consisting of 6-ch1orom-cresol, p-chloro-o-cresol, and p-chloro-m-cresol.

5. The emulsion of claim 1, wherein said condensate has a degree of polymerization of 2 to 10*.

6. The emulsion of claim 1, wherein the concentration of said sensitizing dye ranges from 0.002 to 0.2 gram per gram mole of silver halide.

7. The emulsion of claim 1 wherein the concentration of said formalin condensate ranges from 1 to 5.0 grams per gram mole of silver halide.

8. The emulsion of claim 1, wherein the weight ratio of the concentration of the sensitizing dye to the formalin condensate ranges from 1:5 to 1:500.

9. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensation is selected from the group consisting of o-chlorophenolformaldehyde condensate, p-chlorophenol-formaldehyde condensate, p-brornophenol-formaldehyde condensate, 2,4- dichlorophenol-formaldehyde condensate, 2-chlorohydroquinone-formaldehyde condensate, 4-chlororesorcinolformaldehyde condensate and 6-ch10ro-m-cresol-formaldehyde condensate, wherein the sensitizing dye is and p-chlorophenol-formaldehyde condensate.

11. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and p-chlorophenol-formaldehyde condensate.

12. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

N 2H5 I and p-chlorophemoi-formaldehyde condensate.

13. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and p-chlorophenol-formaldehyde condensate.

14. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and p-chlorophenol-formaldehyde condensate.

15. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

S C H- O H=C S I on aOM l f/ N H 9380aand p-chlorophenol-formaldehyde condensate.

1 6 16. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and p-bromophenol-formaldehyde condensate.

17. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and p-bromopheno1-formaldehyde condensate.

18. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and p-bromophenol-formaldehyde condensate. o

19. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and p-bromophenol-formaldehyde condensate.

20. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and p=bromophenol-f0rmaldehyde condensate.

17 18 22. The combination of claim 1, wherein the combinaand p-bromophenol-formaldehyde condensate. tion of the sensitizing dye with the formalin condensate is: 24. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

/\ q o (F2115 s I /I=CHCH=CS CHOH=C N I I -03 0 I o=o O=CH-C I C2115 J \N/ I N 1? lzHs 2135 C H C2H5 and o-chlorophenol-formaldehyde condensate. and p-bromophenol-formaldehyde condensate. 25. The emulsion of claim 1, wherein the combination 23. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

of the sensitizing dye with the formalin condensate is:

40 and o-chlorophenol-formaldehyde condensate.

26. The emulsion of claim 1, wherein the combination of the sensitizing dye with the formalin condensate is:

and o-chlorophenol-formaldehyde condensate.

2.7. A photographic light-sensitive element comprising a support having thereon at least one layer containing the silver halide emulsion of claim 1.

References Cited UNITED STATES PATENTS