US3486901A - Direct-print silver halide emulsions containing a halogen acceptor and an amine compound as a stabilizer - Google Patents

Description

United States Patent 3,486,901 DIRECT-PRINT SILVER HALIDE EMULSIONS CONTAINING A HALOGEN ACCEPTOR AND AN AMINE COMPOUND AS A STABILIZER Richard Warren Karlson, Rochester, N.Y., assiguor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Oct. 21, 1966, Ser. No. 588,286 Int. Cl. G03c l /06, 1/28 U.S. CI. 9694 21 Claims ABSTRACT OF THE DISCLOSURE This invention relates to photographic direct-print, silver halide emulsions comprising a nitrogen-containing halogen acceptor and a secondary, tertiary or quaternized amine compound as a stabilizer. In one aspect, cyanine and merocyanine dyes are used in combination with the amine stabilizers in direct-print emulsions to provide improved image properties.

The present invention relates to photography. In one aspect, this invention relates to direct-print, photographic silver halide emulsions. In another aspect, this invention relates to photographic elements comprising a support and at least one direct-print, silver halide layer coated thereon.

Radiation sensitive papers adapted for light recording, e.g., oscillographic recording, are well known. Typical of such papers are the developing-out and print-out type. The develop-out type requires the exposed material to be chemically developed, fixed and washed to provide a useful image. The print-out type of material develops on exposure to light. The print-out type is generally much slower than the developing-out type, and the images are unstable and have a short life.

Another type of radiation-sensitive material, especially suitable for recording actinic radiation, comprises a silver halide emulsion layer which, when exposed to a high intensity source of radiation, forms a latent image which can then be developed by exposure to a second source of radiation of lower intensity. Such direct-writing or direct-printing emulsions are faster than print-out emulsions and require no chemical development. Howevery, many of the recording papers of this latter type have low image stability with respect to time; the background areas tend to build up to obscure the images upon subsequent exposure to light and the image areas tend to fade resulting in low image discrimination.

It is, therefore, an object of this invention to provide a new class of light-developable direct-print, radiationsensitive silver halide emulsions.

It is another object of this invention to provide novel photographic light-developable silver halide emulsions that are characterized as having high density differential between the high density radiation exposed areas and the unexposed areas upon subsequent photodevelopment.

It is another object of this invention to provide new photodevelopable, direct-print, silver halide emulsions that have a high resistance to density loss in the image areas and a high resistance to density build-up in the background areas of the photodeveloped emulsion.

It is another object of this invention to provide novel photographic light-developable, direct-print silver halide emulsions that can be chemically developed and fixed before or after photodevelopment to make archival-quality records.

It is another object of this invention to provide a means for maintaining a high image density and a low background density in a photodeveloped direct-print element.

3,486,901 Patented Dec. 30, 1969 Other objects of this invention will become apparent from the description and claims. These and other objects of the invention are accomplished by a novel, direct-print, radiation-sensitive, silver halide emulsion comprising a nitrogen-containing halogen acceptorand an amine stabilizer. The novel composition provides an unexpected improvement in stabilizing the ratio of image density to background density in a photodeveloped direct-print element during subsequent exposure to room light. The direct-print emulsion comprising the nitrogen-containing halogen acceptor without the amine stabilizer has a relatively poor image stability as compared to the novel composition of this invention. Moreover, the amine stabilizers of this invention are not eifective halogen acceptors; an emulsion comprising the amine stabilizer without the nitrogencontaining halogen acceptor provides relatively poor direct-print image quality. Therefore, it is quite unexpected that a direct-print emulsion comprising the amine stabilizer and the nitrogen-containing halogen acceptor provide an appreciable improvement in direct-print quality.

An additional improvement in image quality of directprint emulsion is observed when the composition of this invention further comprises a cyanine or merocyanine dye. The ratio of image density to background density is further improved with respect to subsequent light exposure after photodevelopment. The difliculties in stabilizing images of direct-print films is apparent from an inspection of the prior literature. Thioethers have been used during theprecipitation step to improve image stability as in McBride, US. Patent No. 3,271,157 issued Sept. 6, 1966. The use of zinc and cadmium nitrate for this purpose is described in German Patent No. 1,177,064. The alkyl amines, as used in the present invention, provide a novel approach to this problem and exhibit an unexpected appreciable improvemnt in maintaining good image discrimination in direct-print elements.

The amine stabilizers utilized in the direct-print emulsions containing the nitrogen containing halogen acceptors of this invention are characterized as having at least one alkyl, hydroxyalkyl or carboxyalkyl radical attached to the nitrogen atom. Moreover, the amine stabilizers are not eflicient halogen acceptors when used alone in directprint emulsions. The amine stabilizers of this invention are generally represented by the formulae:

R2 R R2 2 R NR 1 /NR1N 63 (N) R R R*)... 1 X )m 1 A wherein R is an alkylene radical, R R R and -R can each be a hydrogen atom, a hydroxy radical, an aryl radical, i.e., including those of the naphthyl and phenyl series and such common substituents as alkyl groups, halogen atoms, and the like, a earboxyalkyl radical or a hydroxyalkyl radical provided that at least one of the substituents R R R and R of each compound is an alkyl radical, carboxyalkyl radical or hydroxyalkyl radical; m is a positive integer of l to 2, X is an anion necessary to form a quaternary salt and A is the required number of atoms to form a 5 to 6 member saturated ring.

The nitrogen atoms in said ring have carbon atoms adjacent thereto in the ring to form groups such as morpholine, piperazine, piperidine, thiamorpholine and etc. Moreover, in the preferred amine stabilizers of this invention when the ring contains only 2 heteroatoms they are para to one another.

The saturated ring includes rings containing alkyl radicals, hydroxy radicals, hydroxyalkyl radicals and carboxyalkyl radicals and etc. substituted thereon. It will be understood that compounds containing resonant structures, e.g., a

X XH ll J;

group, in the ring provide unsaturation and are not intended to be included within the saturated ring referred to in the specification and claims.

The salts of the amine stabilizer, such as the alkali metal salts when carboxy groups are present as well as the above-defined quaternary amines are effective stabilizers and are also included within the definition of the amine stabilizer.

The amine stabilizer is utilized in concentrations of about to about 100 g./mole of silver halide in the composition, the concentrations being dependent, of course, on the type of amine used and the effect desired in the composition. In the preferred embodiment the amine is in the secondary, tertiary or quaternary form and is utilized in concentrations of about to about 70 g./mole of silver halide in the composition. Typical examples of suitable amine stabilizers used in the direct-print emulsions of this invention are triethyl amine, ethyl amino ethanol, diethyl amino ethanol, morpholine, l-thiamorpholine-4-ethanol, ethylene dinitrilo tetraacetic acid disodium salt, tetraethylammonium hydroxide, N-ethyl morpholine, N-methyl piperazine, N-ethyl piperadine, diethyl ethylene diamine, and etc.

Typical nitrogen containing halogen acceptors which can be utilized in the emulsions of this invention can be represented by the following formulae:

wherein R R R R R R R R R and R can each be hydrogen atoms, alkyl radicals, aryl radicals, including substituted alkyl and aryl radicals, or acyl radicalse.g.,

wherein R is a hydrogen atom, an alkyl radical or an aryl radical-and R and R can also be amino radicals represented by the formula and imino radicals represented by the formula i N-R" wherein R and R can be a hydrogen atom, an alkyl group, an aryl group, including substituted alkyl and aryl groups, or acyl radicals; X can be oxygen or sulfur, E can be an oxygen atom, a sulfur atom, a selenium atom, or an imino radical; and Q and Z can be the necessary atoms to complete a heterocyclic nucleus generally having 5 to 6 members. Q and Z typically are the necessary atoms to complete such moieties as triazole-thiol, a mercaptoimidazole, an imidazolidine-thione, a triazine-thiol, a thiobarbituric acid, or thiouracil, a urazole including a thiourazole and the like heterocyclic moieties.

With respect to the above formulas of nitrogen-containing halogen acceptors: the aryl radical substituents are those of the naphthyl and phenyl series, and include such common substituents as alkyl groups, halogen atoms, acyl radicals and the like; the alkyl radical substituents typically can contain 1 to 20 carbon atoms and more generally 1 to 8 carbon atoms, and can be substituted with such radicals as aryl radicals, halogen atoms, acyl radicals, and the like.

Examples of specific nitrogen-containing halogen acceptors which can be effectively used with the amine stabilizers of this invention are set out below.

l,3-dimethyl-Z-imidazolidinethione Z-imidazolidinethione l-phenyl-5-mercaptotetrazole Thiosemicarbazide Tetramethylthiourea p-Dimethylaminobenzaldehyde-thiosemicarbazone l-isopentyl-Z-thiourea l- Z-diethylaminoethyl l ,2,5,6-tetrahydro- 1,3,5 -triazine-4-thiol 1,2-bis( l,2,5,6-tetrahydro-l,3,5-triazine-4-thiol)ethane l-phenyl-Z-thiourea l,3-diphenyl-2-thiourea 4-thiobarbituric acid 2-thiouracil l-acetyLZ-thiourea 1,3-dibenzyl-2-thiourea l,1-diphenyl-2-thiourea l-ethyl- 1- or-naphthyl) -2-thiourea 2-mercaptoimidazole 1-phenyl-2-imidazolidinethione 4,5-diphenyl-4-irnidazolidine-2-thione 1-methyl-2-mercaptoimidazole l-n-butyl-l,2,5,6-tetrahydro-l,3,5-triazine-4-thiol Thiourea l-methyl-Z-imidazolidinethione D-mannose thiosemicarbazone Morpholino-Z-propane thiosemicarbazone D-galactose thiosemicarbazone Urazole 3-thiourazole 3,5-dithiourazole 3,5-dithiourazole hydrazine salt 4-aminourazole hydrazine salt Urazole sodium salt 4-( 1-naphthyl)urazole 4-ethylurazole l-phenylurazole 4-pheny1urazole l-butylurazole l-octylurazole 4-butyl-3,5-dithiourazole 1,4-diphenylurazole 1,4-dibutylurazole 1,4-dibutyl-3,S-dithiourazole 1,4-diphenyl-3,S-dithiourazole 1-ethyl-4-phenylurazole l-ethyl-4-phenyl-3,S-dithiourazole 3-thio-5-iminourazole 5-selenourazole Hydrazine Phenylhydrazine hydrochloride 2,5-dichlorophenyl hydrazine p-Tolylhydrazine hydrochloride a-Naphthylhydrazine ot-Benzyl-a-phenylhydrazine p-Toluene sulfonyl hydrazine Hexylhydrazine The concentrations of the described nitrogen-containing halogen acceptors utilized in the silver halide emulsions of the invention can be widely varied in accordance with usual practice. Generally, about .1 to mole percent, and preferably about 1 to 50 mole percent, based on the silver halide in the emulsion of the nitrogen-containing halogen acceptor is utilized.

A wide variety of light-developable, direct-print, photographic silver halide emulsions can be utilized in the invcntion, such being well known to those skilled in the art. Suitable silver halides include silver chloride, silver bromide, silver bromoiodide, silver chloroiodide, and silver chlorobromoiodide. The preferred emulsions are those wherein the halide of the silver halide is predominantly bromide. For a description of suitable emulsions, reference is made to Davey et al., U.S. Patent No. 2,592,250, issued Apr. 8, 1952; Glafkides, Photographic Chemistry, vol. 1, pp. 312, Fountain Press, London; and in McBride, U.S. Patent No. 3,271,157, issued Sept. 6, 1966, wherein is disclosed the preparation of silver halide emulsions with organic thioether silver halide solvents present during the grain growth of the silver halide. In the McBride patent is taught the addition of the thioether silver halide solvent to the colloidal material in which the silver halide is precipitated, during the precipitation of the silver halide or to the silver halide prior to or during the ripening of the silver halide. Typical of such thioethers are 3,6-dithia-1,8-octanediol, 1,10 -dithia- 4,7,13 ,16-tetraoxacyclooctadecane, 7,10-diaza-1,16-dicar boxamido-3,. 4-dithia-hexadecane-6,1l-dione, and 1,17- di- (N-ethylcarbamyl) -6,12-dithia-9-oxaheptadecane. The amount of thioether utilized to prepare the silver halide emulsions can be widely varied although about .1 to 25 g. of thioether per mole of silver halide is generally utilized. The present silver halide emulsions generally have an average grain size of about .1 to microns, and more generally about .5 to 1 micron.

The so-called internal image emulsions can be used in the invention, such having silver halide grains wherein a predominant amount of the sensitivity is internal to the grains. Such internal image emulsions are those which, when measured according to normal photographic techniques by coating 3. test portion of the emulsion on a transparent support, exposing to a light intensity scale having a fixed time between 1 10 and 1 second, bleaching 5 minutes in a 0.3% potassium ferricyanide solution at 65 F. and developing for about 5 minutes at 65 F. in Developer B below (an internal-type developer) have a sensitivity, measured at a density of 0.1 above fog, greater than the sensitivity of an identical test portion which has been exposed in the same way and develop-ed for 6 minutes at 68 F. in Developer A below (a surface-type developer).

DEVELOPER A G. N-methyl-p-aminophenol sulfate 0.31 Sodium sulfite, desiccated 39.6 Hydroquinone 6.0 Sodium carbonate, desiccated 18.7 Potassium bromide 0.86 Citric acid 0 .68 Potassium metabisulfite 1.5 Water to make 1 liter.

DEVELOPER B N-methyl-p-aminophenol sulfate 2.0 Sodium sulfite, desiccated 90.0 Hydroquinone 8.0 Sodium carbonate, monohydrate 52.5 Potassium bromide 5.0 Sodium thiosulfate 10.0

Water to make 1 liter.

Various colloids can be used as vehicles or binding agents in preparing the silver halide emulsions of this invention. Satisfactory colloids which can be used for this purpose include any of the hydrophilic colloids generally employed in the photographic field, including, for exam ple, gelatin, colloidal albumin, polysaccharides, cellulose derivatives, synthetic resins such as polyvinyl compounds, including polyvinyl alcohol derivatives acrylamide polymers and the like. In addition to the hydrophilic colloids, the vehicle or binding agent can contain hydrophobic colloids such as dispersed polymerized vinyl compounds, particularly those which increase the dimensional stability of photographic materials. Suitable compounds of this type include Water-insoluble polymers of alkyl acrylates or methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates and the like.

Although silver halide emulsions are generally made with an equivalent or slight excess of halide ion present, I have found it desirable to add additional water-soluble iodide to the silver halide emulsion after its precipitation but before it is coated. More generally, about .1 to 50 mole percent, and preferably about 1 to 10 mole percent of water-soluble iodide based on the silver halide in the emulsion is used. Illustrative water-soluble iodides include ammonium, calcium, lithium, magnesium, potassium, or sodium iodide.

Lead ions are used in the precipitation or formation of the silver halide of the emulsions of the invention. Watersoluble lead salts are suitably added with the water-solule silver salt to an appropriate water-soluble halide to precipitate the lead-silver halide of the present emulsions. Typical suitable water-soluble lead or plumbous salts include lead acetate, lead nitrate, lead cyanide, and the like. The amount of lead utilized in the silver halide of the emulsions of the invention suitably ranges from about .01 to 5 mole percent based on the silver halide. The presence of a water-soluble lead salt during the silver halide formation or grain growth when preparing the light-developable, direct-print emulsions of the invention is to be distinguished from the addition of a watersoluble lead salt shortly prior to coating and after the silver halide grains have been formed.

The emulsion can be hardened with any suitable hardener for gelatin. Suitable hardeners include formaldehyde polyfunctional hardeners having two or more reactive groups which will react with the gelatin, e.g., halogensubstituted aliphatic acids such as mucobromic acid as described in White, U.S. Patent No. 2,080,019 (issued May 11, 1937); compounds having a plurality of acid anhydride groups such as 7,8-diphenyl-bicy-clo(2,2,2)-7- octene-2,3,5,6-tetracarboxylic dianhydride, or a dicarboxylic or disulfonic acid chloride such as terephthaloyl chloride or naphthalene-1,S-disulfonyl chloride as described in Allen and Carrol, U.S. Patents 2,725,294 and 2,725,- 295 (boih issued Nov. 29, 1955); a cyclic 1,2-diketone such as cyclopentane-1,2-dione as described in Allen and Byers, U.S. Patent 2,725,305 (issued Nov. 29, 1955); a bisester of methane-sulfonic acid, such as 1,2-di(methane, sulfonoxy)ethane as described in Allen and Laakso, U.S. Patent No. 2,726,162 (issued Dec. 6, 1955); 1,3-dihydroxymethyl-benzimadazol-2-one as described in July, Knott and Pollak, U.S. Patent No. 2,732,316 (issued J an. 24, 1956); a glutaraldehyde or a sodium bisulfite derivative thereof, such as 3-methyl-glutaraldehyde bis-sodium bisulfite; a bisaziridine carboxamide, such as trimethylene bis(1-aziridine carboxamide) as described in Allen and Webster, U.S. Patent No. 2,950,197 (issued Aug. 23, 1960); or 2,3-dihydroxy dioxane as described in Jetfreys, U.S. Patent No. 2,870,013 (issued Jan. 20, 1959); or with oxy plant gums as described in Jeflreys et al., U.S. Patent No. 3,062,652 (issued Nov. 6, 1962).

The emulsions of the invention can contain a coating aid, such as saponin; a lauryl or oleoyl monoether of polyethylene glycol as described in Knox and Davis, U.S. Patent No. 2,831,766 (issued Apr. 22, 1958); a salt of a sulfated and alkylated polyethylene glycol ether as described in Knox and Davis, U.S. Patent No. 2,719,087 (issued Sept. 27, 1955); an acylated alkyl taurine, such as the sodium salt of N-oleoyl-N-methyltaurine as described in Knox, Twardokus and Davis, U.S. Patent No. 2,739,891 (issued Mar. 27, 1956); the reaction product of a dianhydride of tetracarboxybutane with an alcohol or an aliphatic amine containing from 8 to 18 carbon atoms which is treated with a base, for example, the sodium. salt of the monoester of tetracarboxybutane as described in Knox, Stenberg, and Wilson, U.S. Patent No. 2,843,487 (issued July 15, 1958); a Water-soluble maleopimarate or a mixture of a Water-soluble rnaleopimarate and a substituted glutamate salt as described it. Knox and Fowler, US. Patent No. 2,823,123 (issued Feb. 11, 1958); an alkaline metal salt of a substituted amino acid, such as disodiurn N-(carbon-p-tert.octylphenoxypentaethoxy)glutamate, or a sulfosuccinarnate, such as tetrasodiurn N-(1,2-dicarboxyethyl)-N-octadecyl sulfosuccinamate, o-r N-lauryl disodium sultosuccinamate.

The above-described emulsions of the invention can be coated on a wide variety of supports in accordance with usual practice. Typical supports for photographic elements of the invention include glass, metals, paper, polyethylene-coated paper, polypropylene-coated paper, cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethylene-terephthalate film and related films of resinous materials and others.

Sensitizing dyes have been found to provide increased stability when added to direct-print, silver halide emulsions comprising the amine stabilizers and nitrogen-containing halogen acceptors of this invention. The dyes provide an additional improvement in stabilizing the ratio of image density to background density upon subsequent exposure to radiation.

Particularly useful dyes in the direct-print composition to provide a stabilizing effect are the cyanine and merocyanine dyes. The merocyanine dyes have the formula:

R -l l(Oll=CH)m b(=C-O)n: =x

| l R21 322 Y wherein X can be a sulfur or a selenium atom; R R R and R are each an alkyl radical (e.g., methyl, ethyl, carbethoxymethyl, carboxymethyl, benzyl (phenylmethyl), fl-sulfoethyl, butyl, etc.), an aryl radical, such as phenyl, tolyl, etc., and R R and R can also be a hydrogen atom; Y is an oxygen atom, a sulfur atom, a selenium atom,

wherein R can be any of the substituents of R and wherein R can be any of the substituents of R 112 is a positive integer of 1 or 2 and preferably 1; n is a positive integer of 1 or 2; when m=l and 11:1 or 2, R can be an alkyl group which collectively with R can form an alkylene bridge on the molecule; and W represents the nonmetallic atoms required to complete a basic heterocyclic nucleus generally having to 6 atoms in the heterocyclic ring such as carbon, sulfur, selenium, oxygen and nitrogen to form such moieties as those selected from the group consisting of those of the thiazole series (e.g., thiazole, 4-methylthiazole, S-methylthiazole, 4-phenylthiazole, 5-phenylthiazole, 4,5-dimethylthiaz0le, 4,5-diphenylthiazole, 4-(2-thienyl)thiazole, etc.) those of the benzothiazole series (e.g., benzothiazole, 4-chlorobenzothiazole, S-chlorobenzothiazole, 6-chlorobenzothiazole, 7- chlorobenzothiazole, 4-methylbenzothiazole, S-methylbenzotbiazole, 6-methylbenzothiazole, S-bromobenzothiazole, -bromobenzothiazole, 4-phenylbenzothiazole, S-phenylbenzothiazole, 4-methoxybenzothiazole, S-methoxybenzothiazole, 6-methoxybenzothiazole, S-iodobenzothiazole, 6- iodobenzothiazole, 4-ethoxybenzothiazole, S-ethoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5,6-dioXymethylenebenzothiazole, S-hydroxybenzothiazole, 6-hydroxybenzothiazole, etc.), those of the naphthothiazole series (e.g., a-naphthothiazole, fl-naphthothiazole, 5-methoxy-B-naphthothiazole, 5-ethoxy-,8- naphthothiazole, 7-methoxy-a-naphthothiazole, 8 rnethoxy a-naphthothiazole, etc.), those of the thianaphtheno-7',6,4,5-thiazole series (e.g., 4'-methoxythianaphtheno-7,6',4,S-thiazole, etc.), those of the oxazole series (e.g., 4-methyloxazole, S-methyloxazole, 4-phenyloxazole,

4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, S-phenyloxazole, etc.), those of the benzoxazole series (e.g., benzoxazole, S-chlorobenzoxazole, S-phenylbenzoxazole, S-methylbenzoxazole, 6-rnethylbenzoxazole, 5,6- dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5 methoxybenzoxazole, 6-rnethoxybenzoxazole, S-ethoxybenzoxazole, -chlorobenzoxazole, S-hydroxybenzoxazole, 6- hydroxybenzoxazole, etc.), those of the naphthoxazole series (e.g., a-naphthoxazole, B-naphthoxazole, etc.), those of the selenazole series (e.g., 4-methylselenazole, 4- phenylselenazole, etc.), those of the benzoselenazole series (e.g., benzoselenazole, 5-chlorobenzoselenazole, S-rnethoxybenzoselenazole, S-hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.), those of the naphthoselenazole series (e.g., u-naphthoselenazole, ,B-naphthoselenazole, etc.) those of the thiazoline series (e.g., thiazoline, 4-rnethylthiazoline, etc.), those of the 2-quinoline series (e.g., quinoline, 3-methylquinoline, S-methylquinoline, 7- methylquinoline, S-methylquinoline, 6-chloroquinoline, 8- chloroquinoline, 6-methoxyquinoline, 6-ethoxyquinoline, 6-hydroxyquinoline, 8-hydroxyquinoline, etc.), those of the 4-quinoline series (e.g., quinoline, 6-methoxyquinoline, 7-methylquinoline, 8-rnethylquinoline, etc.), those of the l-isoquinoline series (e.g., isoquinoline, 3,4-dihydroisoquinoline, etc.), those of the 3,3-dialkylindolenine series (e.g., 3,3-dimethylindo1enine, 3,3,5-trimethylindolcnine, 3,3,7-trimethylindolenine, etc.), those of the 2-pyridine series (e.g., pyridine, 3-methylpyridine, 4-methylpyridine, S-methylpyridine, 6-methylpyridine, 3,4-dimethylpyridine, 3,5-dirnethylpyridinc, 3,6-dimethylpyridine, 4,5-dirnethylpyridine, 4,6-dimethylpyridine, 4-chloropyridine, S-chloropyridine, 6-chloropyridine, 3-hydroxypyridine, 4-hydroxypyridine, S-hydroxypyridine, G-hydroxypyridine, 3-phenylpyridine, 4-phenylpyridine, 6-phenylpyridine, etc.), those of the 4-pyridine series (e.g., 2- methylpyridine, 3-methylpyridine, 2-chloropyridine, 3- chloropyridine, 2,3-dimethylpyridine, 2,5-dimethylpyridine, 2,6-dimethylpyridine, 2-hydroxypyridine, 3-hydroxypyridine, etc.), those of the l-substituted imidazole series (e.g., l-ethylirnidazole, 1-ethyl-4-phenylimidazole, 1,4-dimethylimidazole, 4-rnethyl-l-phenylimidazole, etc.), those of the l-substituted benzimidazole series (e.g., l-ethylbenzimidazole, l-butylbenzimidazole, l-ethyl-4,5-dichlorobenzimidazole, etc.), those of the l-substituted naphthimidazole series (e.g., 1-methyl-u-naphthimidazole, 1- ethyl-a-naphthaimidazole, 1-butyl-B-naphthimidazole, 6- chloro-l-methyl-a-naphthimidazole, etc.), etc. The Y substituent is preferably to form a thio-hydantoin nucleus. When Y is a sulfur atom,

the heterocyclic moiety completed by the substituent W is other than a thiazoline group,

when n is 1. At least one of the substituents R R or R is preferably a higher alkyl radical or a hydrogen atom. The alkyl substituents in the described dyes can be widely varied although alkyls having 1 to 18 carbon atoms are more generally used, those alkyls denominated lower alkyls having 1 to 4 carbon atoms and those alkyls denominated higher alkyls having 5 to 18 and preferably 7 to 18 carbon atoms. The alkyl and aryl radicals of the described dyes can be substituted or unsubstituted. Also useful in my invention are the holopolar dyes represented by Formula I in US. Patent 2,739,964 (Reissued as 24,292).

Typical suitable merocyanine dyes used to spectrally sensitize the emulsions of the invention include:

- (3-ethyl-2-benzothiazolinylidene) ethylidene] rhodanine 5-[ (3-ethyl-2-benzothiazolinylidene) ethylidene] 2- thio-2,4-oxazolidinedione 5-[ (3-ethyl-2-benzothiazolinylidene ethylidene] -3- heptyll -phenyl-2-thiohydantoin 5-[ 1-ethylnaphtho{1,2-d}thiazolin-2-ylidene)ethylidene] -3-n-heptyll-phenyl-Z-thiohydantoin 5-[ (3-ethyl-2-benzothiazolinylidene) ethylidene] -2- thiohydantoin 5- (2,3 -dihydro-9,9-dimethyl-9H-pyrrolo[1,2-a1indoll-ylmethylene -3-ethylrhodanine 5- (3-ethylnaphth{2, l-d}oXazolin-2-ylidene) ethylidene] -3 -n-hepty1- l-phenyl-Z-thiohydantoin 5 3-ethyl-Z-benzoxazolinylidene) ethylidene] -4- thiohydantoin 3-ethyl-5-[ (3-ethyl-2-benzothiazolinylidene ethylidene] -2-thiohydantoin 5- [di 3-ethyl-2-benzothiazolinylidene) isopropylidene] l-methyl-2-thiobarbituric acid 5 [di 3 -ethyl-2-benzothiazolinylidene isopropylidene] 2-thio-barbituric acid 5- [4- (3-ethyl-2-benzothiazolinylidene) 2-butenylidene1- 3-n-heptyl-1-phenyl-2-thiohydantoin 5-[ 3-ethyl-5-phenyl-4-oxazolin-2-y1idene) ethylidene] 3-heptyll -phenyl-2-thiohyclantoin l-methyl-5-[ 1,3,3 -trimethyl-Z-indolinylidene) ethylidene]-2-thiobarbituric acid 5- 3-ethyl-2-benzothiazolinylidene) -3-hepty1lphenyl-Z-thiohydantoin 3-ethyl-5-[ (3-ethyl-2-benzoxazolinylidene) isopropylidene] -2-thio-2,4-oxazolidinedione 5-[ (3-ethyl-2-benzothiazolinylidene) ethylidene] -1- phenyl-Z-thiobarbituric acid 5-[ (3-ethylnaphth{2,1-d}oxazolin-2-ylidene)isopropylidene] -3-heptylrhodanine 1-ethyl-5-[ l-ethylnaphtho{ 1,2-d}thiazolin-2-ylidene isopropylidene] -2-thiobarbituric acid 5-[ l-ethyl-2( 1H)-quinolylidene)ethylidene1-3- lauryl-2-thio-2,4-oxazolidinedione 1-methyl-5-[ (3-methyl-2-thiazolidinylidene ethylidene]-2-thioarbituric acid 5- [4- 3-methyl-2-benzoxazoliny1idene) 1 ,3-neopentylene-Z-butenylidene] -2thiobarbituric acid 5 3-ethyl-2-benzoselenazolinylidene ethylidene] -3 hep tyl-2-thiohydantoin 5 3- l,2-dihydropyrrolo{2, l-d}benzothiazoly methylene] -3-heptyl-1-phenyl-2-thiohydantoin 5-[ 5 ,6-dichloro-1 ,3-diethyl-2-benzimidazolinylidene ethylidene] -1-ethyl-2-thiobarbituric acid 5 (3-ethy1-2-benzothiazoliny1idene ethylidene] -3 heptyl-2-seleno-2,4-thiazolidinedione 5-[ 3-ethyl-2-benzothiazolinylidene) ethylidene1-3- heptyl-2-thio-2,4-selenazolidinedione 5-[ (3-ethyl-2-benzothiazolinylidene ethylidene] -3- hep tyl-rhodanine 5 (3-ethyl-Z-benzothiazolinylidene) ethylidene] -3- lauryl-rhodanine 5-[ 3-ethyl-2-benzoxazolinylidene ethylidene] -3- decyl-l -phenyl-2-thiohydantoin 5-[ (3-ethyl-2-benzoxazolinylidene ethylidene] lheptyl-3-phenyl-2-thiohydantoin 3-heptyl-5-( l-methylnaphtho{ 1,2-d}thiazolin2- ylidene -1-phenyl-2-thiohydantoin wherein Q and T are the same substituents as the W substituent for the above-described merocyanine dyes,

q and m are positive integers of l or 2 and preferably 1, n is a positive integer of 0 to 2, D is an acid anion such as chloride, bromide, iodide, perchlorate, thiocyanate, acetate, methylsulfate, ethylsulfate, benzenesulfonate, toluenesulfonate or the like. R R and R are the respective substituents as defined for the merocyanine dyes, R is the same as the substituents for R and when m=l and n=1 or 2, R can be an alkyl group which collectively with R can form an alkylene bridge on the molecule.

Typical useful cyanine dyes that can be used with the alkyl amines in the emulsions of this invention include:

3,3 -diethyl-9-methylthiacarbocyanine iodide 9-ethyl-3,3'-dimethyl-4,5,4',5'-dibenzothiacarbocyanine bromide 3,3 '-diethyl-9-methyl-5 ,5 -diphenyloxacarbocyanine bromide 3-methyl-l-ethylthia-2-cyanine iodide 3,3 ,9-triethyl-5,5'-diphenyloxacarbocyanine iodide 9-ethyl-3,3 -di B-methoxyethyl -5 ,5 -diphenyloxacarbocyanine iodide Anhydro-3-ethyl-5-phenyl-1'-(4-sulfobutyl)thia- 4-carbocyanine hydroxide 1'-butyl-3-ethylselena-4'-carbocyanine iodide 1-butyl-3-ethyl-4-phenylthia-4-carbocyanine iodid e l',3-diethyloxa-4'-cyanine iodide 1,3-diethyl-4,5-'benzothia-2-cyanine iodide l-ethyl-1'-isopropyl-2,4-cyanine perchlorate 1,3-diethylthia-4'-pyridocyanine iodide l-ethyl-l,8-ethylene-2,4-cyanine iodide l-ethyl-l,3,3-trimethylindo-4'-cyanine iodide The concentration of the dyes utilized to improve stabilization of the direct-print image according to this invention can be widely varied; the concentration of the dye depending on the type of emulsion and according to the effect desired. Generally, concentrations of about 10 to about 1000 mg. of dye per mole of silver halide are utilized. About .05 to about 1 mole percent of the dye based on the silver halide in the emulsion is a typical working range.

In forming a light-developed image with a typical photographic element containing an emulsion of the invention, the photographic element is initially exposed to a relatively short duration and high intensity source of electromagnetic radiation (e.g., at least about .1 footcandle second at an intensity of more than about 100 foot-candles) such as a high intensity light source such as are used in oscillographs described in Heiland, U.S. Patent 2,580,427, issued Jan. 1, 1952, high intensity visible light, x-radiation and the like, to form a latent image in the emulsion of the photographic element. Typical suitable high-intensity light sources are mercury vapor lamps that have high blue and ultraviolet emission, xenon lamps that emit light of wavelengths similar to daylight, and tungsten lamps that have high red light emission. Thereafter the resulting latent image is photodeveloped by over-all exposure of the emulsion to a radiation source (e.g., at least about .0001 foot-candle second) of lower intensity than the original exposure, such as to a conventional fluorescent light, light from incandescent lamps commonly used for general illumination, or even ordinary daylight. Generally, the latent image formed in the emulsion in the first instance is not visible and does not become visible until photodevelopment. Heat is desirably utilized during the photodevelopment step. Typically the subject emulsions are heated to a temperature of about C. to 200 C. for about 1 to 30 seconds and photodeveloped after the initial high intensity exposure.

If desired, photographic elements containing the emulsions of the invention can be permanized by developing and fixing in aqueous chemical developing-out and fixing solutions after the initial exposure forming the latent image, or after the above-described photodevelopment, to make archival-quality records. Developing agents can A Density (D minus D Triethylamine (g. /mole of silver halide):

None

Example A cyanine dye, an amine stabilizer and a nitrogen-containing halogen acceptor utilized in a silver halide emulsion provide improved image discrimination.

A silver chlorobr-omide emulsion is prepared by the procedure of Example 1. A sample containing 1.36 moles of silver is mixed with 1360 ml. of an aqueous solution containing 54.4 gr. of urazole, 71.5 ml. of diethylaminoethanol, and 73.5 ml. of 2N H 50 A sample of this solution containing .0825 mole of silver is mixed with 1.4 mg. of l-phenyl-5-mercaptotetrazole, 33.5 mg. of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene, 14 ml. of a solution containing 1 mg. of 3,3-dimethyl-9-methylthiocarbocyanine bromide and 5 ml. of 5% glutaraldehyde.

The composition was coated and tested as in Example 1. The results showed that the emulsion containing the diethylaminoethanol and the cyanine dye gave a better ratio of image density to background density in the directprint system.

Samples prepared as above except containing cyanine dyes: 5,5 dichloro 3,3',9 triethylthiacarbocyanine bromide; anhydro 5,5 dichloro 9 ethyl 3,3 di(4- sulfoethyl)thiacarbocyanine hydroxide; and anhydro-5,5- dichloro 3,9 diethyl 3' (sulfobutyl) thiacarbocyanine hydroxide also show appreciable improvements in the ratio of image density to background density.

The invention has been described with reference to certain embodiments thereof for purposes of comparison of the compositions of the invention, but it will be understood that variations and modifications of the invention can be made within the scope of the following claims.

I claim:

1. A photographic light developable, direct-print, silver halide emulsion comprising a gelatin and at least one other nitrogen-containing compound which is a halogen acceptor and an amine stabilizer having the formula:

wherein R is an alkylene radical, R R R and R can each be a hydrogen atom, an hydroxy radical, an alkyl radical, an aryl radical, a carboxy radical, an hydroxyalkyl radical or a carboxyalkyl radical, provided that at least one of R R R and R in said stabilizer is an alkyl radical, a carboxyalkyl radical or an hydroxyalkyl radical; m is an integer of 1 to 2, X is an anion and A is the number of atoms required to form 5- or 6-member saturated heterocyclic ring.

2. A photographic light developable, direct-print, silver halide emulsion comprising (1) a halogen acceptor having the formula:

R"NNHC=E Z- wherein R", R", R R R R R R R and R can each be hydrogen atoms, alkyl radicals, aryl radicals X ia radicals,wherein R is a hydrogen atom, an alkyl radical or an aryl radical; X can be oxygen or sulfur, R and R can also be wherein R is an alkylene radical, R R R and R can each be a hydrogen atom, an hydroxy radical, an alkyl radical, an aryl radical, a carboxy radical, an hydroxyalkyl radical or a carboxylkyl radical, provided that at least one of R R R or R in said stabilizer is an alkyl radical, a carboxyalkyl radical or an hydroxyalkyl radical; m is an integer of 1 to 2, X is an anion and A is the number of atoms required to form a 5- or 6-member saturated heterocyclic ring.

3. A photographic, direct-print, silver halide emulsion according to claim 1 comprising (1) a gelatin, (2) at least one other nitrogen-containing compound which is a halogen acceptor and (3) a quaternized organic amine compound as a stabilizer.

4. An emulsion according to claim 2 wherein said halogen acceptor is a urazole compound having the formula:

wherein R R and R can each be a hydrogen atom, an alkyl radical, an aryl radical or a radical wherein R is a hydrogen atom, an alkyl radical or an aryl radical; X can be oxygen or sulfur; E can be an oxygen atom, a sulfur atom, a selenium atom or a =NR radical, wherein R can be a hydrogen atom, an alkyl radical, an aryl radical or a 1 5 radical and Q and Z are the necessary atoms to complete a heterocyclic ring having 5 or 6 members.

5. An emulsion according to claim 1 further including a glutaraldehyde gelatin hardener.

6. An emulsion according to claim 1 further including an oxy plant gum gelatin hardener.

7. An emulsion according to claim 1 wherein said silver halide emulsion comprises silver halide grains precipitated in the presence of lead ions.

8. An emulsion according to claim 1 wherein said silver halide emulsion comprises silver chlorobromide grains having a predominant amount of radiation sensitivity internal to said grains.

9. An emulsion according to claim 1 wherein said alkyl amine is diethyla'minoethanol, said nitrogen-containing halogen acceptor is urazole and said silver halide emulsion comprises silver chlorobromide grains having a predominant amount of radiation sensitivity internal to said grains.

10. An emulsion according to claim 1 wherein the silver halide emulsion comprises silver halide grains precipitated in the presence of a thioether.

11. An emulsion according to claim 1 wherein said amine stabilizer has the formula:

12. An emulsion according to claim 1 wherein the amine stabilizer has the formula:

mamarx n-i 13. An emulsion according to claim 1 wherein the amine stabilizer has the formula:

14. A photographic, direct-print silver halide emulsion according to claim 1 which comprises a cyanine or merocyanine dye.

15. An emulsion according to claim 14 wherein said dye is 5 (2,3 dihydro-9,9-dimethyl-9H-pyrrolo-[1,2-a] -indol- 1-ylmethylene)-3-ethyl rhodanine,

5 [1 18 carb0Xyethyl-4(1H)-pyridylidene]-3-ethyl rhodanine,

3-ethy1-5-[ 1-ethyl-4(H -pyridylidene] -rhodanine or 3,3'-dimethyl-9-methylthiocarbocyanine bromide.

16. An emulsion according to claim 2 wherein said amine stabilizer is diethylaminoethanol.

17. An emulsion according to claim 2 wherein said amine stabilizer is triethylamine.

18. An emulsion according to claim 2 wherein said a-mine stabilizer is tetraethylammonium hydroxide.

19. An emulsion according to claim 2 wherein said amine stabilizer is a morpholine compound.

20. In a method for stabilizing the image characteristics of a light-developable, direct-print emulsion containing a gelatin and at least One nitrogen-containing compound which is a halogen acceptor, the improvement which comprises the addition during the preparation of the emulsion of an amine stabilizer having the formula:

wherein R is an alkylene radical, R R R and R each can be a hydrogen atom, an hydroxy radical, an alkyl radicl, an aryl radical, a carboxy radical, an hydroxyalkyl radical or a carboxyalkyl radical, provided that at least one of R R R or R in said stabilizer is an alkyl radical, a carboxyalkyl radical or an hydroxyalkyl radical; m: is an integer of l to 2, X is an anion and A is the number of atoms required to form a 5- or 6-member saturated heterocyclic ring.

21. In a method for stabilizing the image characteristics of a light-developable, direct-print emulsion containing a gelatin and at least one nitrogen-containing compound which is a halogen acceptor, the improvement which comprises the addition during the preparation of the emulsion of a cyanine or merocyanine dye in combination with an amine stabilizer having the formula:

wherein R is an alkylene radical, R R R and R each can be a hydrogen atom, an hydroxy radical, an alkyl radical, an aryl radical, a carboxy radical, an hydroxy alkyl radical or a carboxyalkyl radical, provided that at least one of R R R or R in said stabilizer is an alkyl radical, a carboxyalkyl radical or an hydroxyalkyl radical, m is an integer of l to 2, X is an anion and A is the number of atoms required to form a 5- or 6-member saturated hetcrocyclic ring.

References Cited UNITED STATES PATENTS 3,017,271 1/1962 Piper 96l09 XR 3,128,183 4/1964 Jones et al. 96-107 3,271,157 9/1966 McBride 96107 3,367,780 2/1968 Fix et al 96109 XR NORMAN G. TORCHIN, Primary Examiner R. E. FIGHTER, Assistant Examiner US. Cl. X.R. 96-107, 109

STATES PATENT OFFICE 0F CORRECTION Patent Dated December 30. 1969 Inventofls) Karl son It is error appears in the above-identified patent and that eaidLett ere Patent are hereby corrected as shown below:

"improvemnt" should read improvement- Column 3;, :lineffl before "triazolethiol", should be inserted thfiwo era Column 5, line 71, after "derivatives", should be nserted Column 8, lines L B-n6, "1 ethyl-fl-naphthainiidatole" should read 1 -ethyl- [-naphthimidazole Colman 9",fline 145, that portion of formula reading "-2-thioarbiturio"should read 2-thiobarbiturio line 50, that portion ofyformulareading "benzothiazoly)" should read benzothiazolylJfl Column 1 2, line 5, "backgronud" should read baokgroundy- Column 1L lines 1-5, Formula B set forth as should read 1 Column 114., line "L 5,l l'oarboxylkyl" should read carboxyalkyl Column '16,;QClaim 20, lines 16-17, "radial" should read radical SIGNED AND SEALED a v JUN 1 6 1970 Eamammmn.

1 mm 1:. seem Attestmg Officer I commissioner of ht;