US3761270A

US3761270A - Photographic element composition and process

Info

Publication number: US3761270A
Application number: US00184219A
Authority: US
Inventors: Mauriac R De; R Landholm
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1971-09-27
Filing date: 1971-09-27
Publication date: 1973-09-25
Anticipated expiration: 1990-09-25
Also published as: CA996802A; GB1400244A; BE789364A

Abstract

IN A PHOTOTHERMOGRAPHIC ELEMENT, COMPOSITION OR PROCESS FOR PRODUCING DEVELOPED IMAGES IN COLOR EMPLOYING PROCESSING WITH HEAT, A COMBINATION OF (A) A COLOR-FORMING COUPLER, (B) PHOTOSENSITIVE SILVER HALIDE, (C) AN OXIDATION-REDUCTION IMAGE-FORMING COMBINATION CONTAINING (I) SILVER BENZOTRIAZOLE, WITH (II) AN AMINOPHENOL REDUCING AGENT, AND (D) A BASE-RELEASE AGENT, PROVIDE IMPROVED COLOR IMAGES. AFTER EXPOSURE, A COLOR IMAGE CAN BE DEVELOPED BY HEATING A PHOTOGRAPHIC ELEMENT CONTAINING THIS COMBINATION. ADDENDA EMPLOYED IN PHOTOSENSITIVE AND THERMOSENSITIVE MATERIALS FOR PROCESSING WITH HEAT CAN BE EMPLOYED WITH THIS COMBINATION.

Description

United States Patent 3,761,270 PHOTOGRAPHIC ELEMENT, COMPOSITION AND PROCESS Richard A. de Mauriac and Richard A. Landholm,

Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y.

No Drawing. Filed Sept. 27, 1971, Ser. No. 184,219 Int. Cl. G03c 1/02, 1/72, 1/40 U.S. Cl. 96-77 32 Claims ABSTRACT OF THE DISCLOSURE In a photothermographic element, composition or process for producing developed images in color employing processing with heat, a combination of (a) a color-forming coupler, (b) photosensitive silver halide, (c) an oxidation-reduction image-forming combination containing (i) silver benzotriazole, with (ii) an aminophenol reducing agent, and (d) a base-release agent, provide improved color images. After exposure, a color image can be developed by heating a photographic element containing this combination. Addenda employed in photosensitive and thermosensitive materials for processing with heat can be employed with this combination.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to photosensitive elements, compositions and processes for providing a developed image in color by heating the element or composition after exposure. In one of its aspects it relates to photosensitive elements, for providing such a developed image in color, containing photosensitive silver halide and certain oxidationreduction image-forming combinations with a color-forming coupler. In another of its aspects it relates to photosensitive compositions, for providing such a developed image in color, containing the described components. A further aspect relates to a process of developing an image, in color, in an exposed photosensitive and thermosensitive element, containing the described components by uniformly heating the element.

Description of the state of the art It is well known to develop a latent image in a photographic silver halide element using processing with heat. After exposure, the resulting latent image in the photographic element is developed and, in some cases, stabilized, merely by heating the photographic element. Such a process is described, for example, in U.S. 3,152,904 of Sorensen et al., issued Oct. 13, 1964; U.S. 3,301,678 of Humphlett et al., issued Jan. 31, 1967; U.S. 3,392,020 of Yutzy et al., issued July 9, 1968; U.S. 3,457,075 of Morgan et al., issued July 22, 1969; British 1,131,108 published Oct. 23, 1968; German 888,045 issued June 29, 1943 and British 1,161,777 published Aug. 20, 1969.

Certain photosensitive materials for producing a developed image in color are set out in U.S. Pat. 3,531,286 of Renfrew, issued Sept. 29, 1970. However, the reducing agent employed in such materials is a p-penylenediamine which can be unsuitably toxic. When the p-phenylenediamine is replaced with a less toxic reducing agent which is an aminophenol, as demonstrated in following Examples 8-40, no suitable color image is developed. No suitable solution to this problem is evident from U.S. Pat. 3,531,286 of Renfrew, issued Sept. 29, 1970.

There accordingly has been a need to provide photosensitive materials for producing a developed image in color which materials employ less toxic reducing agents than p-phenylenediamine, and still provide a desired image in color.

SUMMARY OF THE INVENTION It has been found according to the invention that a developed image in color, employing materials containing Patented Sept. 25, 1973 reducing agents less toxic than p-phenylenediamine, can be provided, with processing with heat, employing a photothermographic element and/or composition also described herein as photosensitive element and/or composition with a combination of (a) a color-forming coupler, (b) photosensitive silver halide, (c) an oxidation-reduction imageforming combination comprising (i) silver benzotriazole with (ii) an aminophenol reducing agent, (d) a base-release agent, and (e) a binder. It is a significant feature of the invention, as illustrated in following Examples 8- 10, that a base-release agent be employed with the described combination because in the absence of such a base-release agent, no desired color image is developed upon heating.

DETAILED DESCRIPTION OF THE INVENTION One embodiment of the invention is a photosensitive element for producing a developed image in color comprising a support,

(a) a color-forming coupler, (b) photosensitive silver halide, (c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) an amino phenol reducing agent, ((1) a base-release agent, and (e) a binder.

A range of color-forming couplers can be employed in the described elements and compositions of the invention. The exact mechanism by which the color image is produced is not fully understood. However, it is believed that the color coupler reacts with oxidized developing agent to form desired dye. Color coupler, as employed herein, is accordingly used to mean a compound or mixture of compounds which with other components of the described element or composition provide a desired color image upon heating after exposure. These are designated as color couplers since it is believed that the compounds couple with the oxidized developer to provide the desired dye. The color-forming couplers, as employed herein, are also known as photographic dye-forming couplers. Suitable color couplers are described, for example, in the following U.S. patents as well as in Mees and James, The Theory of the Photographic Process, 3rd edition, 1966, pages 387-394;

Color couplers U.S. Pat. No. Issue date Magenta dye forming 1G). Feniak et a1.

Apr. 19, 1960. Dec. 31, 1968. Feb. 13, 1945. Nov. 6, 1962. Oct. 31, 1961. July 7, 1970.

Mar. 28, 1967. June 17, 1952. Oct. 13, 1959.

Oct. 26, 1965. J an. 12, 1960.

pyysepegepsap c0610.!

Oyan dye forming Sahrfiinen et a1.

A magenta dye-forming coupler useful according to the invention is 1-(2,4,6 trichlorophenyl)-3-[3-{a-(3-pentadecylphenoxy)butyramido}benzamido] 5 pyrazolone. A useful cyan dye-forming coupler is 2,4-dichloro-1-naphthol. And, a useful yellow dye-forming coupler is tit-[3'- {a-(2,4-di-tert. amylphenoxy)acetamido} benzoyl1-2- fluoroacetanilide. Choice of a suitable color-forming coupler will be influenced by the desired color, other components of the described photosensitive element, processing conditions, particular reducing agent employed, processing temperature and time, and the like. One test for a suitable color-forming coupler-reducing agent combination is as follows:

The following solutions are mixed:

Chlorobenzene solution containing silver behenate (7.5 molar) ml 2.0 Chlorobenzene solution containing 2,4 dichloro-lnaphthol (1.5 10- molar) ml 1.0 Chlorobenzene solution containing 4-amino-2,6-diiodophenol (1.5 10- molar) ml 1.0 Triethylamine drop 1 Chlorobenzene to total volume of ml 10.0

The resulting composition is heated for 3 minutes at a temperature of 70 C. The colorless composition is observed to change to a blue color and has a maximum absorption of 620 nm. and an optical density equal to 1.2. This indicates the described combination is suitable to provide a blue color. By employing other desired colorforming couplers, other colors can be provided according to this test.

For example, when the test procedure for a suitable color-forming coupler, as described, is followed with the exception that 1 (2,4,6 trichlorophenyl)3-[3-{u-(3- pentadecylphenoxy)butyramido}benzamido] 5 pyrazolone is substituted for 2,4-dichloro-l-naphthol and 4 amino-2,6-dibromophenol is substituted for 4-amino-2,6- diiodophenol in the described test solution, a dye is formed which provides a colored solution having a maximum absorption of 540 nm. and an optical density equal to 1.0 after heating the mixture for 3 minutes at 70 C.

The described photosensitive element and/or composition contains photosensitive silver halide. In the described photosensitive composition, it is believed that the photosensitive silver halide acts as a catalyst for the oxidationreduction image-forming combination. A typical concentration range of photosensitive silver halide is from about 0.005 to about 0.50 moles of photosensitive silver halide per mole of silver benzotriazole. Examples of suitable photosensitive silver halides are silver chlorides, silver bromide, silver bromoiodide, silver chlorobromoidide, or mixtures thereof. The photosensitive silver halide is typically present with the other components of the described photosensitive element and/or composition in the form of an emulsion which is a dispersion of the photosensitive silver halide in a suitable binder. The photosenstive silver halide can be coarseor fine-graind, very fine-grain silver halide being especially useful. The emulsion containing the photosensitive silver halide can be prepared by any of the well-known procedures in the photographic art, such as single-jet emulsions, double-jet emulsions, such as Lippman emulsions, ammoniacal emulsions, thiocyanate or thioether ripened emulsions, such as those described in US. Pats. 2,222,264 of Nietz et al. issued Nov. 14, 1940; 3,320,069 of Illingsworth issued May 15, 1967 and 3,271,157 of McBridge issued Sept. 6, 1966. Surface image silver halide emulsions can be used. If desired, mixtures of surfaceand internal-image silver halide emulsions can be used as described in US. Pat. 2,996,332 of Luckey et al. issued Apr. 15, 1961. Negative-type emulsions can be used. The silver halide can be a regular-grain silver halide such as described in Klein and Moisar, Journal of Photographic Science, Volume 12, No. 5, Septemher-Octobe .96 p ges 242-251.

The silver halide employed in the practice of the invention can be unwashed or washed to remove soluble salts. In the latter case, the soluble salts can be removed by chill-setting and leaching or an emulsion containing the silver halide can be coagulation-washed.

The silver halide employed in the practice of the invention can be sensitized with chemical sensitizers, such as with reducing agents; sulfur, selenium or tellurium compounds; gold, platinum or palladium compounds; or combinations of these. Suitable procedures are described, for example, in US. Pats. 1,623,499 of Shepard issued Apr. 5, 1972, 2,399,083 of Waller et al. issued Apr. 23, 1946, 3,297,447 of McVeigh issued Jan. 10, 1967, and 3,297,446 of Dunn issued Jan. 10, 1967.

Photosensitive silver halide employed in the practice of the invention can be protected against the production of fog and can be stabilized against loss of sensitivity during keeping. Suitable antifoggants and stabilizers, e.g., used alone or in combination include, for example, thiazolium salts; azaindenes; mercury salts as described, for example, in US. Pat. 2,728,663 of Allen et al. issued Dec. 27, 1955; urazoles; sullfocatechols; oximes described, for example, in British Pat. 623,448; nitron; nitroindazoles; polyvalent metal salts described, for example, in US. Pat. 2,839,405 of Jones issued June 17, 1958; platinum, palladium and gold salts described, for example, in US. Pat. 2,566,263 of Trivelli et al. issued Aug. 28, 1951, and 2,597,915 of Yutzy et al. issued May 27, 1952.

If desired, the photosensitive silver halide can be prepared in situ in the photosensitive and thermosensitive element and/or composition employed in the practice of the invention. The photosensitive silver halide is accordingly prepared in the mixture of one or more of the other components of the described photosensitive element and/ or composition rather than prepared separate from the described components and then admixed with them. Such a method is described, for example, in US. Pat. 3,457,075 of Morgan et al., issued July 22, 1969. For example, a dilute solution of a halogen acid, such as hydrochloric acid, can be applied to the surface of a thin coating containing silver benzotriazole on a suitable substrate followed by removal of the solvent if desired. Silver halide is thus formed in situ throughout the surface of the coating of the organic silver salt.

The photosensitive silver halide can be prepared on the oxidizing agent, such as the silver benzotriazole, prior to application of the silver halide on the support employed. This is also described in U. S. Pat. 3,457,075 of Morgan et al., issued July 22, 1969. For example, a halogen acid, such as hydrochloric acid or hydrobromic acid, can be mixed with silver benzotriazole in a suitable reaction medium. A halide salt more soluble than organic silver salt can be added to a suspension of the organic silver salt to form the desired silver halide. A suitable reaction medium includes Water or other solutions which do not interfere with the reaction.

The described silver benzotriazole and the reducing agent are believed to form an image-forming combination which is designated herein as an oxidation-reduction image-forming combination. This oxidation-reduction image-forming combination is believed to be catalyzed by the described catalyst upon exposure and heating. Silver benzotriazole can be prepared by methods known in the art, such as described in Canadian Pat. 847,351 issued July 21, 1970. Silver benzotriazole in combination with a reducing agent is described, for example, in British Pat. 1,161,777 published Aug. 20, 1969; however, this reference does not relate to production of images in color.

A suitable concentration of the described silver benzotriazole will depend upon the particular components of the photosensitive element and/or composition, processing temperature, desired image and the like. A concentration of silver benzotriazole found useful is about 1 to about moles of silver benzotriazole per mole of described reducing agent.

A range of aminophenol reducing agents can be employed in the described oxidation-reduction image-forming combination in the described elements and/or compositions'of the invention. The most suitable aminophenol reducing agent will depend upon the particular components of the photosensitive and thermosensitive element and/or composition, the particular coupler employed, processing temperature, and the like. Useful aminophenol reducing agents can be determined employing the described test for color couplers. Useful aminophenol reducing agents include, for example, compounds of the formula:

wherein R and R are each, individually, hydrogen, alkyl containing 1 to 3 carbon atoms, such as methyl, ethyl or propyl, chlorine, bromine or iodine; R and R are each, individually, hydrogen or alkyl containing 1 to 3 carbon atoms.

Examplesof useful aminophenol reducing agents according to the invention include:

4-amino-2,6-dibromophenol 4-amino-2-methylphenol sulfate 4-amino-3-methylphenol sulfate 4-amino-2,6-diiodophenol 4-amino-2,-dichlorophenol hydrochloride The useful concentration of aminophenol reducing agent employed in the photosensitive elements and/ or compositions of the invention will depend on the particular components of the photosensitive compositions, processing conditions, desired color of developed image, and the like. A useful concentration of aminophenol reducing agent is about 0.01 moles to about 1.0 moles of aminophenol reducing agent for each mole of silver benzotriazole in the described oxidation-reduction image-forming combination. In a photosensitive element an especially useful concentration of aminophenol reducing agent is about 5 milligrams to about milligrams of aminophenol reducing agent per ft. of support. This concentration range corresponds to about 0.02 moles to about 0.04 moles of aminophenol reducing agent per mole of silver benzotriazole in the described oxidation-reduction image-forming combination.

A base-release agent is employed in the described photosensitive element and/ or composition to provide a desired image in color. As illustrated in following comparative. Examples 8-10 in the absence of such a baserelease agent, a desired color image is not obtained. A variety of base-release agents can be employed in the practice of the invention. Such compounds, as employed herein, are compounds, or mixtures thereof, which upon heating release an alkaline component which provides activation of the described photo-sensitive composition. Typical base-release agents are guanidinium salts which release alkali upon heating. Suitable guanidinium salts include, for example, guanidinium trichloroacetate, and diguanidinium oxalate. Such compounds are known to release a base upon heating as described in US. Pat. 3,531,285 of Haist et al., issued Sept. 29, 1970. This reference also describes other suitable guanidinium salts.

The described base-releasing agents can be employed in the described photosensitive elements and/ or compositions of the invention at a concentration which provides desired activation of the oxidation-reduction image-forming combination. A useful concentration is about 0.1 moles to about 1.0 moles of base-release agent to each mole of silver benzotriazole. An especially useful concentration of base-release agent is about 5 milligrams to about 50 milligrams of base-release agent per ft. of support of described photosensitive element. This corresponds to about 0.1 moles to about 1.0 moles of base-release agent to each mole of silver benzotriazole.

Other reducing agents which are not aminophenol reducing agents and which do not adversely affect the desired color image upon heating can be used in combination with the described elements and compositions. Such reducing agents are typically silver halide developing agents and include, for example, hydroquinone, l-phenyl- 3-pyrazolidone developing agent, ascorbic acid developing agents, reductone developing agents, and the like.

An element and composition described and used in the practice of the invention can contain various colloids alone or in combination as vehicles, binding agents and in various layers. Suitable materials are typically hydrophobic, but hydrophilic materials can also be employed. They are transparent or translucent and include both naturally occurring substances such as proteins, for example, gelatin, gelatin derivatives, cellulose derivatives, polysaccharides such as dextran, gum arabic and the like; and synthetic polymeric substances such as watersoluble polyvinyl compounds like poly (vinyl pyrrolidone) acrylamide polymers and the like. Other synthetic polymeric compounds which can be employed include dispersed vinyl compounds such as in latex form and particularly those which increase dimensional stability of photographic materials. Suitable synthetic polymers include those described in US. Pats. 3,142,586 of Nottorf issued July 28, 1964; 3,193,386 of White issued July 6, 1955; 3,062,674 of Houck et al. issued Nov. 6, 1962; 3,220,844 of Houck et al. issued Nov. 30, 1965; 3,287,289 of Ream et al. issued Nov. 22, 1966 and 3,411,911 of Dykstra issued Nov. 19, 1968. Effective polymers include water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl arylates or methacrylates, and those which have cross-linking sites which facilitate hardening or curing, as well as those having recurring sulfobetaine units as described in Canadian Pat. 774,054. Preferred high-molecular-weight materials and resins include polyvinyl butyral, cellulose acetate butyrate, polymethyl methacrylate, poly(vinyl pyrrolidone), ethyl cellulose, polystyrene, polyvinyl chloride, chlorinated rubber, polyisobutylene, butadiene-styrene copolymers, vinyl chloride-vinyl acetate copolymers, copolymers of vinyl acetate, vinyl chloride and maleic acid and polyvinyl alcohol.

The photosensitive and thermosensitive components and other materials employed in the practice of the invention and described herein can be coated on a wide variety of supports. Typical supports include cellulose nitrate film, cellulose ester film, poly(vinylacetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film and relates films or resinous materials, as vrell as glass, paper, metal and the like. Typically, a flexible support is employed, especially a paper or film support.

An especially useful embodiment of the invention is a photosensitive and thermosensitive element, especially a photothermographic element, comprising a support,

(a) a magenta dye-forming coupler comprising l-(2,4,6

trichlorophenyl) 3 -[3 {a-(3-pentadecylphenoxy)butyramido}benzamido]-5-pyrazolone,

(b) photosensitive silver halide,

(c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-amino-2,6-dibromophenol, (d) guanidinium trichloroacetate, and (e) a polyvinyl butyral binder.

If a cyan image is desired, the described magenta dyeforming coupler can be replaced with, for example, 2,4- drchloro-l-naphthol. Moreover, if a yellow image is desired, the described magenta dye-forming coupler and cyan dye forming coupler can be replaced with a yellow dye-forming coupler comprising a-[3-{a-(2,4-di-tert.- amylphenoxy)-acetamido}-benzoyl]-2-fiuoroacetanilide.

A further embodiment of the invention is a multilayer photosensitive and thermosensitive element comprising (a) a magenta dye-forming coupler, as described, (b) a cyan dye-forming coupler, as described, (c) a yellow dye-forming coupler, as described, (d) photosensitive silver halide, (e) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) an aminophenol reducing agent, (f) a base-release agent, such as a guanidinium salt, and (g) a binder.

In a multilayer photosensitive element according to the invention the components of the photosensitive element can be in various layers of the photographic element depending upon the particular components, the desired image, processing conditions and the like. For example, the described photosensitive silver halide can be in a layer separate from the color-forming coupler and/or silver benzotriazole and/or other components of the described photosensitive element and/or composition. It is often desirable, however, to employ the components in a single layer for convenience of coating.

Spectral-sensitizing dyes can be used conveniently to confer additional sensitivity to the elements and compositions of the invention. For instance, additional spectral sensitization can be obtained by treating the silver halide with a solution of a sensitizing dye in an organic solvent or the dye can be added in the form of a dispersion as described in British Pat. 1,154,781. For optimum results, the dye can either be added to the emulsion as a final step or at some earlier stage.

sensitizing dyes useful in sensitizing silver halide emulsions are described, for example, in US. Pats. 2,526,632 of Brooker et al. issued Oct. 24, 1950; 2,503,776 of Sprague issue Apr. 11, 1950; 2,493,748 of Brooker et al. issued Jan. 10, 1950 and 3,384,486 of Taber et al. issued May 21, 1968. Spectral sensitizers, which can be used, include the cyanines, merocyanines, complex (trinuclear or tetranuclear) cyanines, holopolar cyanines, styryls, hemicyanines such as enamine, hemicyanines, oxonols and hemioxonols. Dyes of the cyanine classes can contain such basic nuclei as the thiazolines, oxazolines, pyrrolines, pyridines, oxazoles, thiazoles, selenazoles and imidazoles. Such nuclei can contain alkyl, alkylene, hydroxyalkyl, sulfoalkyl, carboxyalkyl, aminoalkyl, and enamine groups that can be fused to carbocyclic or heterocyclic ring systems either unsubstituted or substituted with halogen, phenyl, alkyl, haloalkyl, cyano, or alkoxy groups. The dyes can be symmetrical or unsymmetrical and can contain alkyl, phenyl, enamine or heterocyclic substituents on the methine or polymethine chain.

The merocyanine dyes can contain the basic nuclei described, as well as acid nuclei such as thiohyd antoins, rhodanines, oxazolidene diones, thiazolidenediones, barbituric acids, thiazolineones and malononitriles. These acid nuclei can be substituted with alkyl, alkylene, phenyl, carboxyalkyl, sulfonalkyl, hydroxyalkyl, alkoxyalkyl, alkylamine groups or heterocyclic nuclei. Combinations of these dyes can be used, if desired. In addition, supersensitizing addena which do not absorb visible light may be included such as, for instance, ascorbic acid derivatives, azaindenes, cadmium salts and organic sulfonic acid as described in US. Pats. 2,933,390 of McFall et al. issued Apr. 19, 1960 and 2,937,089 of Jones et al. issued May 17, 1960.

The sensitizing dyes and other addenda used in the practice of the invention can be added from water solutions or suitable organic solutions can be used. The compounds can be added using various procedures including,

for example, those described in US. Pats. 2,912,343 of Collins et al. issued Nov. 10, 1959; 3,353,605 of McCrossen et al. issued Sept. 19, 1967; 2,996,287 of Audran issued Aug. 15, 1961; and 3,425,835 of Johnson et al. issued Feb. 4, 1969.

Another embodiment of the invention is a photosensitive and thermosensitive composition for producing a developed image in color comprising (a) a color-forming coupler, (b) photosensitive silver halide, (c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) an aminophenol reducing agent, and (d) a base-release agent.

The described photosensitive and thermosensitive composition can contain various concentrations of the described components. Optimum concentrations of particular components will depend upon desired image, processing conditions, particular image-forming combinations and the like. Useful concentrations of components in the described photosensitive and thermosensitive composition comprise for each mole of silver benzotriazole,

(a) 0.01 to 1.0 moles of described color-forming coupler,

(b) 0.1 to 0.5 moles of described photosensitive silver halide,

(c) 0.01 to 1.0 moles of described aminophenol reducing agent, and

(d) 0.1 to 1.0 moles of described base-release agent.

After exposure, the resulting latent image in a photographic element, as described, can be developed by merely overall heating the described photographic element to moderate temperatures. A range of Wavelengths of radiation can be employed for exposure; however, the wave lengths of ordinary light are convenient for exposure purposes. Another embodiment of the invention accordingly is a process of developing an image, in color, in an exposed photosensitive element comprising a support,

(a) a color-forming coupler, as described, (b) photosensitive silver halide, as described, (c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) an aminophenol reducing agent, (d) a base-release agent, and (e) a binder,

comprising heating the described element to about C. to about 250 C. until a desired image is produced.

A temperature range of about 80 C. to about 250 C. can be employed for developing the described image; however, a temperature range of about C. to about 180 C. is usually suitable. By increasing or decreasing the length of time of heating, a higher or lower temperature within the described range can be employed. A developed image is typically produced Within several seconds, such as about 0.5 to about 90 seconds.

Processing is usually carried out under ambient conditions. Temperatures, pressures and humidity outside normal atmospheric conditions can be employed, if desired. However, normal atmospheric conditions are preferred.

Any suitable means can be used for providing the desired processing temperature range. The heating means can be a simple hot plate, iron, roller or the like.

One suitable process of the invention comprises developing a cyan-dye image in a photosensitive and thermosensitive element comprising a support,

(a) a cyan dye-forming coupler comprising 2,4-dichlorol-naphthol,

(b) photosensitive silver bromide,

(c) an oxidation-reduction image-forming combination comprising 9 (i) silver benzotriazole, with (ii) 4-amino-2,6-dibromophenol, (d) guanidinium trichloroacetate, and (e) a polyvinyl butyral binder,

comprising heating the described element to about 100 C. to about 200 C. for about 5 seconds to about 15 seconds. A yellow dye image can be developed in a photosensitive and thermosensitive element similar to that described wherein the color-forming coupler is one which provides a yellow dye rather than a cyan dye. Similarly, other colors can be provided or combinations of colors by employing the desired color-forming coupler.

In most instances, the developed image is sufficiently stable for many purposes. However, if a more stable image is desired, the resulting developed image can be stabilized after heating by contacting the resulting element with a solution of a mercaptoazole, potassium iodide and/ or benzotriazole. An aqueous solution containing about 0.1% to about 5% by weight of such solution of the described compounds is usually suitable. A typical stabilizing solution for this purpose is a 1% by weight solution of phenylmercaptotetrazole in acetone. The described photographic element after overall heating can be immersed in the described solution for a few seconds, e.g., about one to about seconds to provide a desired stable color image.

The photosensitive and other hardenable layers of an element used in the practice of this invention can be hardened by various organic or inorganic hardeners, alone or in combination, such as aldehydes, and blocked aldehydes, ketones, carboxylic and carbonic acid derivatives, sulfonate esters, sulfonyl halides and vinyl sulfonyl ethers, active halogen compounds, epoxy compounds, aziridines, active olefins, isocyanates, carbodiimides, mixed-function hardeners and polymeric hardeners such as oxidized polysaccharides like dialdehyde starch and oxyguar-gum and the like.

The photosensitive elements used in the practice of the invention can contain antistatic or conducting layers. Such layers can comprise soluble salts such as chlorides, nitrates and the like, evaporated metal layers, ionic polymers such as those described in U.S. Bat-s. 2,861,056 of Minsk issued Nov. 18, 1958, and 3,206,312 of Sterman et al. issued Sept. 14, 1965, or insoluble inorganic salts such as those described in U.S. Pat. 3,428,451 of Trevoy issued Feb. 18, 1969. The photosensitive and thermosensitive elements can also contain antihalation materials and antihalation dyes.

The photosensitive layers or other layers employed in the practice of the invention can contain plasticizers and lubricants. Suitable plasticizers and lubricants include, for example, polyalcohols such as glycerin and diols described, for example, in U.S. Pat. 2,960,404 of Milton et al. issued Nov. 1, 1966; fatty acids or esters such as those described in U.S. Pat. 2,588,765 of Robijns issued Mar. 11, 1952; U.S. Pat. 3,121,060 of Duane issued Feb. 11, 1964; and silicone resins such as those described in British Pat. 955,061.

The photosensitive layer or other layers employed in the practice of the invention can contain surfactants such as saponin; anionic compounds such as alkyl aryl sulfonates described, for example, in U.S. Pat. 2,600,831 of Baldsiefen issued June 17, 1962; amphoteric compounds such as those described in U.S. Pat. 3,133,816 of Ben-Ezra issued May 19, 1964; and adducts of glycidol and an alkyl phenol such as those described in British Pat. 1,022,878.

If desired, the photosensitive elements employed in the practice of the invention can contain matting agents such as starch, titanium dioxide, zinc, oxide, silica, polymeric beads including beads described, for example, in US. Pats. 2,922,101 of Jelley et a1. issued July 11, 1961, and 2,761,- 245 of Lynn issued Feb. 1, 1955.

The photosensitive elements and compositions employed in the practice of the invention can contain brightening agents including stilbenes, triazines, oxazoles and coumarin brightening agents. Water-soluble brightening agents 10 can be used such as those described in German Pat. 972,- 067 and U.S. Pat. 2,933,390 of McFall et al. issued Apr. 19, 1960, or dispersions of brighteners can be used such as those described in German Pat. 1,150,274; U.S. Pat. 3,406,- 070 of Oetiker et al. issued Oct. 15, 1968, and French Pat. 1,530,244.

The various layers including the photosensitive and thermosensitive layers of an element employed in the practice of the invention can contain light-absorbing materials, filter dyes, antihalation dyes and absorbing dyes such as those described in U.S. Pats. 2,253,921 of Sawdey issued May 31, 1966; 2,274,782 of Gaspar issued Mar. 3, 1942; 2,527,583 of Silberstein et al. issued Oct. 31, 1950 and 2,956,879 of VanCampen issued Oct. 18, 1960. If desired, the dyes can be mordanted, for example, as described in U.S. Pat. 3,282,699 of Jones et a1. issued Nov. 1, 1966.

The photosensitive and thermosensitive layers used in the practice of the invention can be coated by various coating procedures including dip coating, air-knife coating, curtain coating or extrusion coating using hoppers such as described in U.S. Pat. 2,681,294 of Beguin issued June 15, 1954. If desired, two or more layers can be coated simultaneously such as by the procedures described in U.S. Pat. 2,761,791 of Russell issued Sept. 4, 1956 and British Pat. 837,095.

Stability to print-out from light exposure is further increased by employing highly purified materials; for eX- ample, freedom from halides and sulfides increases stability to light exposure. The use of highly purified silver behenate can, for example, reduce propensity to print-out in background areas of an element prepared according to the invention.

Stabilization of the resulting developed image of a photosensitive element, as described, can also be carried out upon heating when certain compounds which release phenylmercaptotetrazole are employed in the described photosensitive element and/ or composition. Suitable compounds which release phenylmercaptotetrazole are described, for example, in U.S. application Ser. No. 27,151 of Youngquist, filed Apr. 9, 1970.

It is desirable, in some cases, to employ an image stabilizer precursor in the described elements and/or compositions of the invention. These can be employed in the practice of the invention to reduce post processing printout due to room light exposure and to reduce background stain. Suitable stabilizer precursors include, for example, azole thioethers and blocked azole thione stabilizer precursors, such as 5-acetyl-4-methyl-2-(3-oxobutylthio)thiazole, 4-furoyl-3-methylthio 1,2,4 thiadiazole-S-thione, 5-acetyl-4-methyl 3 (3 oxobutyl)thiazoline-2-thione and 2,6-di-tert-butyl 4 (1 phenyl-5-tetrazolyl)thiophenol. These are described, for example, in U.S. application Ser. No. 43,171 of Hiller, filed June 3, 1970, now abandoned. The described stabilizer precursors are suitable in a range of concentration. However, a suitable concentration range is from about 0.002 mole to about 0.10 mole of stabilizer precursor per mole of silver benzotriazole in the described element and/or composition.

A range of colorless onium halides can be employed in the described elements or compositions to provide an additional increase in photosensitivity, i.e., speed, and in some cases to obtain a reduction in the background density. Typical speed increasing onium halides are quaternary ammonum halides, quaternary phosphonium halides and/ or tertiary sulfonium halides such as l-phenethyl-Z-picoliniurn bromide, tetraethyl phosphonium bromide or trimethylsulfonium iodide. Optimum concentrations for the described onium halides will vary depending upon the particular components of the photosensitive composition, processing conditions, desired image and the like. A concentration of onium halide in the described element and/ or composition is about 0.010 mole to about 0.05 mole of onium halide per mole of photosensitive silver halide employed. Suitable onium halides are described in U.S.

11 application Ser. No. 43,172 of DeMauriac and Hiller, filed June 3, 1970 and now US. Pat. No. 3,679,422.

In some cases a non-aqueous, polar, organic solvent such as a compound containing a carbamyl, S or S0 moiety in a described photosensitive element and/or composition suitable for processing with heat can provide improved maximum image densities. Suitable non-aqueous solvents include, for example, tetrahydrathiophene- 1,1-dioxide, 4-hydroxy butanoic acid lactone and methylsulfonylmethaue. Suitable non-aqueous, polar, organic solvents are described in US. application Ser. No. 33,966 of Bojara and DeMauriac, filed May 1, 1970 and now US. Pat. No. 3,667,959.

A divalent metal salt which has the property of amplifying the developed image can be employed in the practice of the invention to cause an increase in maximum image density. A suitable divalent metal salt image amplifier is zinc acetate, cadmium acetate or cupric acetate. The described image amplifying compounds are suitable in a range of concentrations depending upon the particular components of the photosensitive composition, processing conditions, desired image and the like. A suitable concentration range is usually about 0.005 to about 0.20 moles of divalent metal salt image amplifier per mole of heavy metal salt oxidizing agent, i.e., silver benzotriazole. Suitable divalent metal salt image amplifiers are described in US. application Ser. No. 43,173 of Hiller, filed June 3, 1970 and now US. Pat. No. 3,708,304.

The following examples are included for a further understanding of the invention.

EXAMPLE 1 A light-sensitive dispersion is prepared by ball-milling the following components for about 18 hours:

Silver benzothiazole g 42.0 Polyvinyl butyral g 30.0 Acetone-toluene (1:1 parts by volume) ml 500.0

After the dispersion is prepared, 3.8 grams of lithium bromide is added to the composition and the resulting mixture is stirred for 3 to minutes. Two milliliters of the resulting light-sensitive dispersion is combined with the following solutions:

4-amino-2,6-dibromophenol (1.0% by weight in acetone) Magenta dye-forming cupler, 1-(2,4,6-trichlorophenyl)-3-[3-{a-(3 pentadecylphenoxy)butyramido} benzamido]5-pyrazolone (1.0% by weight in acetone) 2.0 Guanidinium trichloroacetate (1.0% by weight in acetone) 2.0 Methanol to total volume of 7.0

EXAMPLE 2 The procedure set out in Example 1 is repeated with the exception that a cyan dye-forming coupler, i.e., 2,4- dichloro-l-naphthol, is employed in place of the described magenta dye-forming coupler.

A sample of the resulting photosensitive element containing the cyan dye-forming coupler is exposed in the Same manner as described in Example 1 and heated as 12 described in Example 1 to provide a well-defined cyan dye image having 14 visible density steps.

EXAMPLE 3 The procedure set out in Example 1 is repeated with the exception that a yellow dye-forming coupler, i.e., a-[3-{0c-(2,4 di-tert.-amylphenoxy)acetamido}benzoyl]- 2-fluoroacetanilide, is employed in place of the described magenta dye-forming coupler of Example 1.

A sample of the photosensitive element containing the yellow dye-forming coupler is exposed and processed as described in Example 1. A yellow dye image results having 9 visible density steps.

EXAMPLES 4-7 The resulting dispersion is thoroughly mixed, coated on a photographic paper support at a wet thickness of 0.004 inch and dried.

Samples of the photosensitive elements are sensitometrically exposed to tungsten light for 6 seconds on a contact printer and processed by overall heating the resulting photosensitive element for about 7 seconds on a curved hot block at a temperature of C. Magenta dye photographic images result in each instance. Table I provides the number of visible density steps produced according to this process.

TABLE I Number of visible steps Example Aminophenol reducing agent present 4 4-arnino-2-mcthylphenol sulfate 5 4amino-3-methy1pheno1 sulfate 10 6 4-amino-2,6-diiodophenol 12 7 4-arnino-2,G-diehlorophenol hydrochloride..- 9

EXAMPLE 8 This is a comparative example.

The procedure set out in Example 1 is repeated with the exception that guanidinium trichloroacetate is omitted from the described photosensitive and thermosensitive element. Subsequent exposure to tungsten light in the same manner as described in Example 1 for 6 seconds on a contact printer and processing by overall heating for 10 seconds on a curved hot block at a temperature at 170 C. produces no significant visible image.

EX MPLE 9 This is a comparative example.

The procedure set out in Example 2 is repeated with the exception that guanidinium trichloroacetate is omitted. After exposing a sample of the resulting photosensitive element sensitometrically to tungsten light on a contact printer as described in Example 1 for 6 seconds and processing for 10 seconds by overall heating on a curved hot block at a temperature of 170 0., no significant visible image is produced.

EXAMPLE 10 EXAMPLE 11 A photosensitive and thermosensitive element is prepared by combining 2 milliliters of the dispersion resulting from the mixture of silver benzotriazole with lithium bromide from Example 1 with the following components:

Ml. 4-amino- 2,6-dibromophenol (1.0% by Weight in acetone) c 1.0 Magenta dye'forming coupler, 1-(2,4,6-trichlorophenyl) 3 [3 a-(3-pentadecylphenoxy)butyramidobenzamido]-5-pyrazolone (1.0% by weight in acetone) 1.0

Diguanidinium oxalate (1.0% by weight in methanol) 1.0

Actone-toluene (1:1 by volume) to a total volume of 7.0

The resulting dispersion is thoroughly mixed, coated on ia suitable photographic paper support at a wet thickness of 0.004 inch and dried.

.A' sample of the resulting photosensitive element is sensitometrically exposed for 60 seconds to tungsten light Q on a contact printer. The resulting latent image is developed by overall heating the photosensitive element on a curved hot block for about 8 seconds at a temperature of about 170 C. A magenta dye image results having 16 visible image density steps.

EXAMPLE 12 The procedure set out in Example 11 is repeated with the exception that monoguanidinium malonate is employed in place of the described diguanidinium oxalate.

Upon exposure and processing, as described in Example 11, a magenta dye image results having 14 visible density steps.

EXAMPLE 13 The procedure set out in Example 11 is repeated with the exception that diguanidinium pimelate is employed in place of the described diguanidinum oxalate.

Upon exposure and processing of the resulting photosensitive element, as described in Example 11, a magenta dye image results having 14 visible density steps.

EXAMPLE 14 The procedure set out in Example 11 is repeated with the exception that 2,4-dichloro-1-naphthol, a cyan dyeforming coupler, is employed in place of the magenta dye-forming coupler described in Example 11.

The resulting photosensitive element is exposed and processed by overall heating as described in Example 11 to produce a cyan dye image having 15 visible density steps.

EXAMPLE 15 The procedure set out in Example 12 is repeated with the exception that 2,4-dichloro-1-naphthol, a cyan dyeforming coupler, is employed in place of the described magenta dye-forming coupler.

Upon exposure and processing as described in Example 11, the resulting the resulting photosensitive element provides a cyan dye image having 14 visible density steps.

EXAMPLE 16 The procedure set out in Example 13 is repeated with the exception that 2,4-dichloro-1-naphthol, a cyan dyeforming coupler, is employed in place of the described magenta dye-forming coupler.

Upon exposure and processing of the resulting photosensitive element, as described in Example 11, a cyan dye image is produced having 13 visible density steps.

EXAMPLE 17 A silver benzotriazole dispersion is prepared by ballmilling the following components:

Silver benzotriazole g 42.0 Poly(vinylbutyral) g 30.0 Actone-toluene (1:1 by volume) ml 500 for 96 hours. 0.75 grams of lithium bromide is then added to 100 milliliters of the resulting dispersion and the mixture is ball-milled for 18 hours.

A photosensitive and thermosensitive film is prepared by coating the following composition on a polyethylene terephthalate film support at a thickness of 0.004 inch:

amido]-5-pyrazolone 1.0 Actone containing 2% by weight of guanidinium trichloroacetate 2.0

The resulting photosensitive element is exposed sensitometrically for 6 seconds to tungsten light on a contact printer. The resulting latent image is developed by overall heating the photographic element for about 10 seconds on a curved hot block at a temperature of C.

A well-defined magenta dye image results having 18 visible density steps.

EXAMPLE 18 The procedure set out in Example 17 is repeated with the exception that the photosensitive element, after processing with heat, is immersed in a methanol bath containing 1% by weight benzotriazole. The photosensitive element is permitted to remain in solution for 60 seconds. A stable image results.

EXAMPLE 19 The procedure set out in Example 17 is repeated with the exception that the resulting photosensitive element, after processing with heat, is immersed in a methanol bath containing 1% by weight potassium iodide for about 60 seconds. A stable developed image results.

EXAMPLE 20 The procedure set out in Example 17 is repeated with the exception that the resulting photosensitive element is immersed in a methanol bath containing 1% by weight 1-phenyl-4-mercaptotetrazole for about 60 seconds. A developed stable image results.

In some cases it can be advantageous to prepare the silver salt of the benzotriazole by simultaneous addition of a first solution containing benzotriazole and a second solution of a silver salt, such as silver nitrate or silver trichloroacetate, into a third solution containing a polymeric peptizer, preferably a binder to be used in the described photosensitive and/or composition, such as poly(vinyl butyral). An example of this is as follows:

Several solutions are prepared having the following compositions:

Solution A: 41.0 g. (0.186 moles) of silver trifluoroacetate dissolved in 100 milliliters of acetone Solution B: 22.1 g. (0.185 moles) of benzotriazole dissolved in 100 milliliters of acetone Solution C: 30.0 g. of polyvinyl butyral dissolved in 300 milliliters of acetone Solution D: 58.0 milliliters of a percent lithium bromide in acetone Solutions A and B are added at a controlled rate of addition to Solution C over a period of about 36 minutes. When all of Solutions A and B are added to Solution C, the resulting dispersion is digested for about 10 minutes. Following this digestion period, Solution D is rapidly added and the dispersion is stirred for another 10 minute period. The resulting silver halide-silver benzotriazole crystals can be washed with water. The resulting silver bromide-silver benzotriazole dispersion after drying is suitable for use in the described photosensitive elements and/or compositions without ball-milling.

This procedure can be used wherein silver benzotriazole is replaced with, for example, silver behenate or other desired silver salt.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be elfected within the spirit and scope of the invention.

What is claimed is:

1. A photothermographic element for producing a developed image in color comprising a support,

(a) a color-forming coupler,

(b) photosensitive silver halide,

(c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) a para-aminophenol reducing agent,

(d) a lbase-release agent that has the property of releasing base upon heating, and

(e) a polymeric binder.

2. The photothermographic element of claim 1 wherein said base-release agent is a guanidinium salt.

3. The photothermographic element as in claim 1 wherein said aminophenol reducing agent is 4-amino-2-methylphenol sulfate,

4-amino-3-methylphenol sulfate, 4-amino-2,6-diiodophenol,

4-amino-2,6-dichloropheno1 hydrochloride, or

4-amino-2,6-dibromophenol.

4. The photothermographic element of claim 1 also comprising 3-carboxymethyl 5 [(3-mcthyl 2(3H)- thiazolinylidene) isopropylidene] rhodanine.

5. A multilayer photothermographic element comprismg (a) a magenta dye-forming coupler,

(b) a cyan dye-forming coupler,

(c) a yellow dye-forming coupler,

(d) photosensitive silver halide,

(e) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) a para-aminophenol reducing agent,

(f) a base-release agent which has the property of releasing base upon heating, and

(g) a polymeric binder.

6. The photothermographic element of claim 1 also comprising a spectral sensitizing dye.

7. The photothermographic element of claim 1 comprising, for each mole of said silver benzotriazole,

(a) 0.01 to 1.0 mole of said color-forming coupler,

(b) 0.1 to 0.5 mole of said photosensitive silver halide,

(c) 0.01 to 1.0 mole of said para-aminophenol reducing agent, and

(d) 0.1 to 1.0 mole of said base-release agent.

8. A photothermographic composition for producing a developed image in color comprising (a) a color-forming coupler,

(b) photosensitive silver hali 16 (c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) a para-aminophenol reducing agent, and

(d) a base-release agent which has the property of releasing base upon heating.

9. The photothermographic composition of claim 8 comprising (a) a magenta dye-forming coupler comprising 1-(2,4,

6 trichlorophenyl) 3 [3 {a pentadecylphenoxy) butyramido}benzamido] -5-pyrazolone (b) photosensitive silver bromide,

(c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-amino-2,6-dibromophenol,

(d) guanidinium trichloroacetate, and

(e) a polyvinyl butyral binder.

10. The photothermographic composition of claim 8 comprising (a) a yellow dye-forming coupling comprising a-[3- {a (2,4, di t amylphenoxy) acetamido} benzoyl]-2-fluoroacetanilide,

(b) photosensitive silver bromide,

(d) guanidinium trichloroacetate, and

(e) a polyvinyl butyral binder.

11. The photothermographic composition of claim 8 also comprising 3-carboxymethyl-5-[(3-methyl-2(3H)- thiazolinylidene isopropylidene] rhodanine.

12. The photothermographic composition of claim 8 wherein said base-release agent is a guanidinium salt.

13. The photothermographic composition of claim 8 wherein said aminophenol reducing agent is 4-amino-2-methylphenol sulfate,

4-amino-3-methylphenol sulfate, 4-amino-2,6-diiodophenol,

4-amino-2,6-dichlorophenol hydrochloride, or

4-amino-2,6-dibromophenol.

14. The photothermographic composition of claim 8 comprising (a) a cyan dye-forming coupler comprising 2,4-dichloro-l-naphthol (b) photosensitive silver bromide,

(c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-amino-2,6-dibromophenol, comprising (d) guanidinium trichloroacetate, and

(e) a polyvinyl butyral binder.

15 The photothermographic composition of claim 8 also comprising a spectral sensitizing dye.

16. The photothermographic composition of claim 8 comprising for each mole of said silver benzotriazole,

(a) 0.01 to 1.0 moles of said color-forming coupler,

(b) 0.1 to 0.5 moles of said photosensitive silver halide,

(c) 0.01 to 1.0 moles of said aminophenol reducing agent, and

(d) 0.1 to 1.0 moles of said base-release agent.

17. A process of developing an image, in color, in an exposed photothermographic element comprising a support.

(a) a color-forming coupler,

(b) photosensitive silver halide,

(c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) a para-aminophenol reducing agent, (d) a base=release agent, and

(e) a polymeric binder comprising heating said element to about 80 C. to about 250 C.

18. The process of claim 17 of developing an image, 'm color, comprising heating said element at about 80 C. to about 250 C. for about 0.5 to about 60 seconds.

19. A process of developing a cyan dye image in a photothermographic element comprising a support,

(a) a cyan dye-forming coupler comprising 2,4-dichloro-l-naphthol,

(b) photosensitive silver bromide,

tion comprising an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-amino-2,6-dibromophenol,

(d) guanidinium trichloroacetate, and

(e) a polyvinyl butyral binder comprising heating said element to about 100 C. to about 200 C. for about 5 seconds to about 15 seconds.

20 A process of developing an image, in color, in an exposed, multilayer, photothermographic element comprising a support,

(a) a magenta dye-forming coupler,

(b) a cyan dye-forming coupler,

(c) a yellow dye-forming coupler,

(d) photosensitive silver halide,

(f) a base release agent which has the property of releasing base uopn heating, and

(g) a polymeric binder comprising heating said element to about 80 C. to about 250 C.

21. The process of claim 20 comprising heating said element to about 80 C. to about 250 C. for about 5 seconds to about 15 seconds.

22. The process of developing and stabilizing an image, in color, in a photothermographic element comprising a support,

(a) a color-forming coupler,

(b) photosensitive silver halide,

(d) a base-release agent which has the property of releasing base upon heating, and

(e) a polymeric binder comprising heating said element to about 80 C. to about 250 C. until a developed, color image is produced, then stabilizing the resulting image with a solution of a mercapto azole, potassium iodide or benzotriazole.

23. The process of claim 22 wherein said stabilizing is carried out by immersing said element, after said heating, in a 1% by weight solution of phenylmenoaptotetrazole in acetone.

24. A photothermographic element for producing a developed image in color comprising a support,

(a) a magenta dye-forming coupler comprising 1-(2,4,

6 trichlorophenyl) 3 [3 {a-(3-pentadecylphenoxy) butyrarnido} benzamido] -5-pyrazolone (b) photosensitive silver bromide,

(c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-amino-2,o-dibromophenol,

(d) guanidinium trichloroacetate, and

(e) a polyvinyl butyral binder.

25. A photothermographic element for producing a developed image in color comprising a support,

(a) a cyan dye-forming coupler comprising 2,4-dichloro-l-naphthol,

(b) photosensitive silver bromide,

(c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-amino-2,6-dibromophenol (d) guanidinium trichloroacetate, and

(e) a polyvinyl butyral binder.

26. A photothermographic element for producing a developed image in color comprising a support,

(a) a yellow dye-forming coupler comprising a-[3-{uz- (2,4 di -tert. -amylphenoxy)acetamido} benzoyl]- 2-fiuoroacetanilide (b) photosensitive silver bromide,

(d) guanidinium trichloroacetate, and

(e) a polyvinyl butyral binder.

27. A multilayer photothermographic element for producing a developed image in color comprising a support,

(a) a magenta dye-forming coupler comprising 1-(2,

4,6 trichlorophenyl 3 [3 {a (3 pentadecylphenoxy)butyramido}benzamido]-5-pyrazolone (b) a cyan dye-forming coupler comprising 2,4-dichloro-l-naphthol,

(c) a yellow dye-forming coupler comprising -[3-{a- (2,4 di tert. amylphenoxy)acetamido} benzoyl]-2-fluoroacetanilide,

(d) photosensitive silver bromide,

(e) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-arnino-2,6-dibromophenol, (f) guanidinium trichloroacetate, and (g) a polyvinyl butyral binder.

28. A process of developing a magnenta dye image in a photothermographic element comprising a support,

(a) a magenta dye-forming coupler comprising 1- (2,4,6 trichlorophenyl) 3 {a (3 pentadecylphenoxy) butyramido}benzamido] -5-pyrazolone (b) photosensitive silver bromide, (c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-amino-2,6-dibromophenol (d) guanidinium trichloroacetate, and (e) a polyvinyl butyral binder comprising heating said element to about C. to about 200 C. for about 5 seconds .to about 15 seconds.

29. A process of developing a yellow dye image in a photothermographic element comprising a support,

(a) a yellow dye-forming coupler comprising a-[3- {oz (2,4 di t amylphenoxy) acetarnido} benzoyl -2-fiuoroacetanilide (b) photosensitive silver bromide,

(c) an oxidation-reduction image-forming combination comprising (i) silver benzotriazole, with (ii) 4-amino-2,6-dibromophenol, (d) guanidinium trichloroacetate, and (e) a polyvinyl butyral binder comprising heating said element to about 100 to about 200 C. for about 5 to about 15 seconds.

30. A photothermographic element for producing a developed image in color comprising a support,

(a) a magenta dye-forming coupler,

(b) photosensitive silver halide,

(c) an oxidation-reduction image forming combination comprising (i) silver benzotriazole, with (ii) a para-aminophenol reducing agent, (d) a guanidinium compound base release agent, and (e) a polymeric binder.

31. A photothermographic element for producing a developed image in color comprising a support,

(a) a cyan dye-forming coupler, (b) photosensitive silver halide, (c) an oxidation-reduction image forming combina- 5 tion comprising (i) silver benzotriazole, with 3220846 (ii) a para-aminophenol reducing agent, 3457075 (d) a guanidinium compound base release agent, and 3531286 (e) a polymeric binder. 1

32. A photothermographic element for producing a developed image in color comprising a support,

(a) a yellow dye-forming coupler, (b) photosensitive silver halide, (c) an oxidation-reduction image forming combination 15 comprising (i) silver benzotriazole, with (ii) a para-aminophenol reducing agent,

(d) a guanidininm compound base release agent, and (e) a polymeric binder.

References Cited UNITED STATES PATENTS NORMAN G. TORCHIN Primary Examiner A. T. SURO PICO, Assistant Examiner US. Cl. X.R.

7 0 U I iITE1 J 'ST A L' I n'IS PATENT orrlch reel-gr;5176127 2 Dated some 25, 973 Inv qc fl Richard deM ure Richard A. Landholm It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, lines 58-59, p-pen ylehediamlne" should read ---p-p henyler ediamir e-.

Column 2, line 56 ete" should read ---et-. I Line 60, "13,066,759" should read 3,oo6,759---.

Column 3, line 51, "chlorides" should read 1 ---chloride-*--q Line 58, "fine-graind" should read fine-graj.n----.

Column A, in 12, 1972' should read -----l927--.

Column 6, line 36, "arylates" should read ---la.cr ylates---. l

Column line 9 lkyl" Should read -Sulfoa.lkyl---. V ,2

' column 8, line 2, 3,353,605 should read ---3,3 l2,6o5-- Column 11; line '36 *oenzothiazole" should read benzotriaZole----. Line l, cupler should read ----coupler-.

V, Columl1 l3, lihe 27, "Aotohe-toluene should read ---Ac:ecohe-coluene------. LlheT F, "the resulting" (second occurrence) should be deleted ""-'7f rage '4 g X Y wh m eras PATENT @FFEEZE @ERTlFi-CATE Gil C(ERHQTHN 337 3 7 Daz d 'ihzpcembe'r 25, 19Y3 and Richard A, Lahdholm Pacenc lNd.

Inventofls) Richard A, deMaurlac It is certified that error appears in the above-=identified patent and that said Let zters Patent are hereby corrected as shown below:

r Actohe -toluene should read Column 1M,'1ine 16,

Line 28 MO" should read ---l.,O--.

Line 33,

---Acetone-toluene---.

d ---Acetone--=.

Line 29, Actone" should rea "Actohe" should read ---Acetohe---.

Column 16 line 53 "comprising" should be deleted. Column l7 line 12, biOIl comprising should "be deleted.

that part of the formula reading trichlorophehyl should read ---trichlorophenyl)---. Line 37', maghenta should read ----mageh'r a- -v Line L l, that part of the formula read "3-{of should read ---3-[3- d Column 18, line 23,

Signed and sealed this 1st day of October 1974.

(SEAL) Attest:

Ce MARSHALL DANN MecoY M0 GIBSON JR Attesting Officer Commissioner of Patents