US3708304A

US3708304A - Use of divalent metal salt image amplifiers in photosensitive and thermosensitive elements

Info

Publication number: US3708304A
Application number: US00043173A
Authority: US
Inventors: G Hiller
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1970-06-03
Filing date: 1970-06-03
Publication date: 1973-01-02
Anticipated expiration: 1990-01-02
Also published as: FR2095790A5; BR7103419D0; DE2127110A1; CA984207A; BE768073A

Abstract

A divalent metal salt, such as zinc acetate, cadmium acetate or cupric acetate, in combination with an oxidation-reduction imageforming combination containing a heavy metal salt oxidizing agent, such as silver behenate, and a reducing agent, such as a bis-naphthol reducing agent, in a photosensitive and thermosensitive element suitable for dry processing with heat, provides increased image density with no adverse increase in background density. A combination of a bis- Beta -naphthol reducing agent and zinc acetate, cadmium acetate or cupric acetate in conjunction with a stable source of silver for physical development is useful in photosensitive elements for dry processing with heat. The element can contain a sensitizing dye, an activator-toning agent and other addenda employed in elements for dry processing with heat. A stable, developed image can be provided by heating the element after exposure. The photosensitive component can be photographic silver halide or other suitable photosensitive metal salts.

Description

United States Patent 91 Hillel 1 Jan. 2, 1973 [54] USE OF DIVALENT METAL SALT IMAGE AMPLIFIERS IN PHOTOSENSITIVE AND THERMOSENSITIVE ELEMENTS [75] Inventor: Gary Lynn Hiller, Rochester, NY.

[73] Assignee: Eastman Kodak Co., Rochester,

[22] Filed: June3, 1970 [21] Appl. No.: 43,173

Puerckhauer Ohkubo ..96/1 14.1

FOREIGN PATENTS OR APPLICATIONS 1,161,777 9/1969 Great Britain OTHER PUBLICATIONS Chemical Abstracts, Vol. 68, 1968, pg. 64585,

reference at 64592f, Light-developable printing-out photosensitive material.

Primary Examiner-J. Travis Brown Assistant Examiner-Judson R. Hightower Attorney-W. H. J. Kline, Bernard D. Wiese and Richard E. Knapp ABSTRACT A divalent metal salt, such as zinc acetate, cadmium acetate or cupric acetate, in combination with an oxidation-reduction image-forming combination containing a heavy metal salt oxidizing agent, such as silver behenate, and a reducing agent, such as a bis-naphthol reducing agent, in a photosensitive and thermosensitive element suitable for dry processing with heat, provides increased image density with no adverse increase in background density. A combination of a bis-B- naphthol reducing agent and zinc acetate, cadmium acetate or cupric acetate in conjunction with a stable source of silver for physical development is useful in photosensitive elements for dry processing with heat. The element can contain a sensitizing dye, an activator-toning agent and other addenda employed in elements for dry processing with heat. A stable, developed image can be provided by heating the element after exposure. The photosensitive component can be photographic silver halide or other suitable photosensitive metal salts.

27 Claims, No Drawings USE OF DIVALENT METAL SALT IMAGE AMPLIFIERS IN PHOTOSENSITIVE AND TI-IERMOSENSITIVE ELEMENTS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to photosensitive elements, compositions and processes for developing a latent image using so-called dry processing with heat. In one lates to a dry process of developing and increasing the maximum image density in a photosensitive and thermosensitive element containing a reducing agent, an oxidizing agent and an image-amplifying divalent metal salt, as described 2. Description of the State of the Art It is known that, in a photographic element containing a gelatin-peptized silver halide emulsion, watersoluble inorganic acid salts can be used to inhibit fog in both fresh and incubated coatings. They are particularly effective in photographic elements sensitized by alkylene oxide polymers, as described in U.S. Pat. No. 2,839,405 ofJones published June 17,1958.

Metallic salts, such as stannous stearate, are known image amplifiers for a thermographic, non-silver halide image-receptor sheet, such as described in U.S. Pat. No. 3,460,946 of Puerckhaver et al. issued Aug. 12, 1969. These image-receptor sheets contain a reducing agent, such as 2,6-ditertiary -butyl-pcresol, an oxidizing agent such as silver behenate and a toner, e.g., (2H )-phthalazinone; however, they are not photosensitive. An intermediate photosensitive sheet containing, for example, 4-methoxy-l-naphthol is first given a reflex exposure while in contact with the original. The exposed photosensitive intermediate sheet is then heated while in contact with the image-receptor sheet.

It is known to obtain an image in a photosensitive element suitable for so-called dry processing with heat. The photosensitive element can contain a reducing agent, a light insensitive silver salt of an organic acid as an oxidizing agent and photographic silver halide, such as described in U.S. Pat. No. 3,152,904 of Sorensen and Shepard issued Oct. 13, 1964, and U.S. Pat. No. 3,457,075 of Morgan and Shely issued July 22, 1969. Elements of this type are also described, for example, in French Pat. No. 1,441,619 and Belgian Pat. No. 705,872.

It is also known that the addition of mercuric ion, e.g., in the form of mercuric acetate at about 0.005 to about 0.05 mole per mole of silver, to a heat-developable photographic printing sheet containing photographic silver halide, an organic silver salt and a reducin g agent causes an increase in photographic speed and acts as an image amplifier, as well as an incubation antifoggant, as described in German Pat. No. 1,908,761

issued Feb. 18, 1969, or corresponding South African Pat. No. 903,080 published Feb. 27, 1969.

Unfortunately, in some cases these elements suffer from having poor spectral sensitivity and in some cases the resulting images after processing are of low maximum density, undesirably warm tone and have high background density.

There has been a continuing need for a photosensitive and thermosensitive element which provides higher image density, a more neutral (black) tone and less background density due to poor post-processing print-out.

SUMMARY OF THE INVENTION According to the invention, the described improvements are provided in a photosensitive and thermosensitive element composition or process with an oxidation-reduction image-forming combination comprising (i) a heavy metal salt oxidizing agent with (ii) a reducing agent, a catalyst for said oxidation-reduction imageforming combination and a binder, by employing a divalent metal salt image amplifier, which is a zinc, cadmium or copper salt, with the described combination.

DETAILED DESCRIPTION OF THE INVENTION A number of divalent metal salts which are image amplifiers can be employed in the practice of the invention to cause an increase in maximum image density with more neutral'tone without undesirably increased background density. A suitable image-amplifying compound is a divalent metal salt, e.g., a zinc salt such as zinc acetate. Other suitable inorganic divalent metal salts which can be employed in the practice of the invention include acetate salts of cadmium and copper.

The described image-amplifying compounds are suitable in a range of concentration of about 0.005 to about 0.20 mole of divalent metal salt per mole of heavy metal salt oxidizing agent, e.g., per mole of silver salt oxidizing agent; however, they are especially suitable at a concentration of about 0.010 mole to about 0.10 mole of divalent metal salt per mole of silver salt oxidizing agent.

hotosensitive and thermosensitive elements, which are suitable for dry processing with heat, can provide a developed image by physical development as described, for example, in U.S. Pat. No. 3,457,075 of Morgan et al. issued July 22, 1969. Other elements of this type are described, for example, in U.S. Pat. No. 3,429,706 of Shepard et al. issued Feb. 25, 1969, and U.S. Pat. No. 3,152,904 of Sorensen et a1. issued Oct. 13, 1964. V

The described element contains a photosensitive salt, especially a photosensitive silver salt. It is believed this is a catalyst for the described oxidation-reduction image-forming combination. A typical concentration range of photosensitive silver salt is about 0.005 to about 0.50 mole of photosensitive silver salt per mole of heavy metal salt oxidizing agent, e.g., per mole of silver behenate. Preferred photosensitive silver salts are photosensitive silver halides, e.g., silver chloride, silver bromide, silver bromoiodide, chlorobromoiodide, or mixtures thereof. The photosensitive silver halide can be coarseor finegrain, very fine-grain emulsions being especially useful. The emulsion containing the photosensitive silver hasilver.

lide can be prepared by any of the well-known procedures in the photographic art, such as single-jet emulsions, double-jet emulsions, such as Lippmann emulsions. ammoniacal emulsions, thiocyanate or thioether ripened emulsions, such as those described in U.S. Pat. No. 2,222,264 of Nietz et al. issued Nov. 14, 1940, U.S. Pat. No. 3,320,069 of lllingsworth issued May 15,1967, and U.S. Pat. No. 3,271,157 of McBride 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 U.S. Pat. No. 2,996,332 of Luckey et al. is-

.sued Apr. 15, 1961. Negative-type emulsions can be used. The silver halide emulsion can be a regular-grain emulsion such as described in Klein and Moisar, Journal ofPhotographic Science, Volume 12, No. 5, Sept.- Oct. 1964), pages 24225 1.

The silver halide emulsions 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 the emulsion 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 U.S. Pat. No. 1,623,499 of Shepard issued Apr. 5, 1927; U.S. Pat. No. 2,399,083 of Waller et al. issued Apr. 23, 1946; U.S. Pat. No. 3,297,447 of McVeigh issued Jan. 10, 1967; and U.S. Pat. No. 3,297,446 of Dunn issued Jan. 10, 1967.

Photosensitive silver halide emulsions 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 U.S. Pat. No. 2,728,663 of Allen et al. issued Dec. 27, 1955; urazoles; sulfocatechols; oximes described, for example, in British Pat. No. 623,448; nitron; nitroindazoles; polyvalent metal salts described, for example, in U.S. Pat. No. 2,839,405 of Jones issued June 17, 1958; platinum, palladium and gold salts described, for example, in U.S. Pat. No. 2,566,263 of Trivelli et al. issued Aug. 28, 1951, and U.S. Pat. No. 2,597,915 of Yutzy et al. issued May 27,1952. 1

Suitable organic reducing agents which can be employed in the described combination include, for example, phenol and naphthol reducing agents. The bisnaphthol which is preferred is a bis-B-naphthol of the formula:

wherein R, and/or R are hydrogen, alkyl with one to three carbon atoms, alkoxy, e.g., alkoxy containing one to two carbon atoms, such as methoxy or ethoxy; halogen, nitro, amino or a diazonium halide salt, and n is 0 or 1. Suitable bis-B-naphthols which can be employed in the practice of the invention include:

2,2'-dihydro xy- 1 ,1 -binaphthyl, 6,6'-dibromo-2,2'-dihydroxy-1,1'-binaphthyl, 6,6'-dinitro-2,2-dihydroxy-1,1'-binaphthyl and/or bis-(2-hydroxy-l-naphthyl)methane. The described reducing agents are suitable in a range of concentration; however, they are especially suitable at a concentration from about 0.10 to about 2.0 moles, e.g., about 0.40 mole to about 0.75 mole, of reducing agent per mole of oxidizing agent, as described.

Other reducing agents, which are typically silver halide developing agents, can be used in conjunction with the above bis-naphthol reducing agents. Suitable silver halide developing agents include, for example, polyhydroxybenzenes such as hydroquinone developing agents, e.g., hydroquinone, alkyl-substituted hydroquinones as exemplified by tertiary butylhydroquinone, methylhydroquinone, 2,5-dimethylhydroquinone and 2,6-dimethylhydroquinone; catechols and pyrogallol; halo-substituted hydroquinones such as chlorohydroquinone or dichlorohydroquinone; alkoxy-substituted hydroquinones such as methoxyhydroquinone or ethoxyhydroquinone; methylhydroxynaphthalene; phenylenediamine developing agents; methylgallate; aminophenol developing agents, such as 2,4- diaminophenols and methylaminophenols; ascorbic acid developing agents such as ascorbic acid, ascorbic acid ketals and ascorbic acid derivatives such as those described in U.S. Pat. No. 3,337,342 of Green issued Aug. 22, 1967; hydroxylamine developing agents such as N,N'-di-(2-ethoxyethyl)hydroxylamine; 3- pyrazolidone developing agents such as l-plienyl-3- pyrazolidone and 4-methyl-4-hydroxymethyl-l-phenyl- 3-pyrazolidone'including those described in British Pat. No. 930,572 published July 3, 1963; hydroxytetronic acid, and hydroxytetronimide developing agents, reductone developing agents such as anhydrodihydropyrrolidino hexose reductone; and.the like.

It is desirable to employ an activator-toning agent in the elements, compositions and processes of the invention to obtain a desired image, particularly 'when phenolic reducing agents are used. A suitable activatortoning agent is a heterocyclic activator-toning agent containing at least one nitrogen atom and of the formula:

where R is hydrogen, hydroxyl, or a metal ion such as potassium, sodium, lithium, silver, gold or mercury; Z represents atoms completing a heterocyclic nucleus, especially a 5- or 6-member heterocyclic nucleus. The atoms completing the heterocyclic nucleus can be, for example,

or an alkylene group containing three or four carbon 5 moiety, in a photosensitive and thermosensitive eleatoms. The atoms completing the heterocyclic nucleus can contain various substituent groups, such as amino, alkyl amino, e.g., methylamino or ethylamino, hydroxyl, carbamyl and the like. An especially suitable activator-toning agent is a heterocyclic activatortoning agent containing at least one nitrogen atom which is preferably a cyclicimide of the formula:

wherein R can be hydrogen, hydroxyl, or a metal ion such as potassium, sodium, lithium, silver, gold or mercury; Z represents carbon atoms of a series completing a cyclicimide nucleus, typically consisting of from five to six carbon atoms, e.g., a phthalimide or succinimide nucleus. The atoms of the cyclicimide nucleus can contain various substituent groups, especially amino, alkyl, such as alkyl containing one to five carbon atoms, such as methyl, ethyl, propyl, butyl or pentyl or aryl, such as aryl containing six to 20 carbon atoms, such as phenyl, tolyl and xylyl.

Examples of suitable activator-toning agents which can be employed in the practice of the invention include:

phthalimide,

N-hydroxyphthalimide,

N-potassium phthalimide,

N-silver phthalimide,

N-mercury phthalimide,

succinimide and/or N-hydroxysuccinimide.

The described activator-toning agents are suitable in a range of concentration depending on several factors such as the desired image, the particular oxidationre'duction image-forming combination, processing tem-' perature and the like. However, they are especially suitable at a concentration from about 0.10 mole to about 1.05 moles of activator-toning agent per mole of oxidizing agent, as described.

Other so-called activator-toning agents can be employed in combination with other components of the described photosensitive and thermosensitive element in the practice of the invention. Various compounds which have been designated as toners can be employed for this purpose. Typically, a heterocyclic organic toning agent containing at least two hetero atoms in the heterocyclic ring of which at least one is a nitrogen atom is employed. These are described, for example, in U.S. Pat. No. 3,080,254 of Grant issued Mar. 5, 1963. Suitable toners include, for example, phthalazinone, phthalic anhydride, 2-acetylphthalazinone and 2- phthalylphthalazinone. Other suitable toners are described, for example, in U.S. Pat. No. 3,446,648 of Workman issued May 27, 1969.

A non-aqueous, polar, organic solvent, such as a compound containing a ment suitable for dry processing with heat can provide improved maximum image densities, e.g., tetrahydrothiophene-1,1-dioxide, 4-hydroxybutanoic acid lactone and/or methylsulfinylmethane.

The described elements comprise a heavy metal salt oxidizing agent, especially a silver salt oxidizing agent, e.g., a silver salt of an organic acid. The silver salt of the organic acid should be resistant to darkening under illumination to prevent undesired deterioration of a developed image. An especially suitable class of silver salts of organic acids is represented by the water-soluble silver salts of organic acids of long-chain fatty acids which are stable to light. Compounds which are suitable silver salts include, for example, silver behenate, silver stearate, silver oleate, silver laurate, silver hydroxystearate, silver caprate, silver myristate and silver palmitate. Other suitable oxidizing agents are, for example, silver benzoate, silver phthalazinone, silver benzotriazole, silver saccharin, silver 4'-n-octadecyloxydiphenyl-4-carboxylic acid, silver O-aminobenzoate, silver acetamidobenzoate, silver furoate, silver camphorate, silver P-phenylbenzoate, silver phenylacetate, silver salicylate, silver butyrate, silver terephthalate, silver phthalate, silver acetate and silver acid phthalate. Oxidizing agents which are not silver salts can be employed, if desired, such as zinc oxide, gold stearate, mercuric behenate, auric behenate and the like, but silver salts are preferred.

A photosensitive and thermosensitive element, and emulsions 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 U.S. Pat. No. 3,142,586 of Nottorf issued July 28, 1964; U.S. Pat. No. 3,193,386 of White issued July 6, 1955; U.S. Pat. No. 3,062,674 of Houck et al. issued Nov. 6, 1962; U.S. Pat. No. 3,220,844 of l-louck et al. issued Nov. 30, 1965; U.S. Pat. No. 3,287,289 of Ream et al. issued Nov. 22, 1966; and US. Pat. No. 3,411,911 of Dykstra issued Nov. 19, 1968. Effective polymers include water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates 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. No. 774,054. Preferred high-molecularweight materials and resins include polyvinyl butyral, cellulose acetate butyrate, polymethyl methacrylate,

poly(vinylacetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film and related films or resinous materials, as well as glass, paper, metal and the like. Typically, a flexible support is employed, especially a paper support which can be partially-acetylated or coated with baryta and/or an alphaolefin polymer, particularly a polymer of an alphaolefin containing two to 10- carbon atoms such as polyethylene, polypropylene, ethylene-butene copolymers and the like.

The photosensitive and thermosensitive 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 oxyguargum and the like.

The photosensitive and thermosensitive 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. Pat. No. 2,861,056 of Minsk issued Nov. 18, 1958, and U.S. Pat. No. 3,206,312 of Sterman et al. issued Sept. 14,1965, or insoluble inorganic salts such as those described in U.S. Pat. No. 3,438,451 of Trevoy issued Feb. 18, 1969. The photosensitive and thermosensitive elements can also contain antihalation materials and antihalation dyes.

The photosensitive and thermosensitive 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. No. 2,960,404 of Milton -et al. issued Nov. 1, 1966; fatty acids or esters such as those described in U.S. Pat. No. 2,558,765 of Robijns issued Mar. 11, 1952; U.S. Pat. No. 3,l2l,060 of Duane issued Feb. 11, 1964; and silicone resins such as those described in British Pat. No. 955,061.

The photosensitive and thermosensitive layers 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. No. 2,600,831 of Baldsiefen issued June 17, 1962; amphoteric compounds such as those described in U.S. Pat. No. 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. No. 1,022,878.

If desired, the photosensitive and thermosensitive 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 U.S. Pat. No. 2,922,101 of Jelley et, al. issued July 11, 1961, and us. Pat. No. 2,701,245 of Lynn issued Feb. 1, 1955.

The photosensitive and thermosensitive elements employed in the practice of the invention can contain brightening agents including stilbenes, triazines, oxazoles and coumarin brightening agents. Water-soluble brightening agents can be used such as those described in German Patent No. 972,067 and U.S. Pat. No. 2,933,390 of McFall et al. issued April 19, 1960, or dispersions of brighteners can be used such as those described in German Pat. No. 1,150,274, U.S. Pat. No. 3,406,070 of Oetiker et al. issued Oct. 15, 1968, and French Pat. No. 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. Pat. No. 3,253,921 of Sawdey issued May 31, 1966; U.S. Pat. No. 2,274,782 ofGaspar issued Mar. 3, 1942; U.S. Pat. No. 2,527,583 of Silberstein et al. issued Oct. 31 1950; and U.S. Pat. No. 2,956,879 of VanCampen issued Oct. 18, 1960. If desired, the dyes can be mordanted, for example, asdescribed in U.S. Pat. No. 3,282,699 of Jones et al. 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, airknife coating, curtain coating or extrusion coating using hoppers such as described in U.S. Pat. No. 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. No. 2,761,791 of Russell issued Sept. 4, 1956, and British Pat. No. 837,095.

If desired, thephotosensitive silver halide can be prepared in situ, in the photosensitive and thermosensitive coatings of an element employed in the practice of the invention. Such a method is described, for example, in U.S.Pat. No. 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 an organic silver salt, such as silver behenate, 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 silver behenate or silver stearate or other organic silver salt, prior to application of the silver halide on the support employed. This is also described in U.S. Pat. No. 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 an organic silver salt in a suitable reaction medium. A halide salt more soluble than the organic silver salt can be added to a suspension of the organic silver salt to form the silver halide. A suitable reaction medium includes water or other solutions which do not interfere with the reaction.

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

A range of azole thioethers and/or blocked azole thiones can be employed in the practice of the invention to improve post-processing stability, e.g., to reduce post-processing print-out due to room-light exposure and to reduce background stain. A suitable stabilizer precursor is a heterocyclic stabilizer precursor which is an azole compound of the formula:

wherein Z represents atoms completing a or 6- member heterocyclic nucleus, such as thiazole, thiadiazole, thiazoline and tetrazole; R is alkyl containing l to carbon atoms, e.g., methyl, ethyl, propyl, butyl and pentyl,

or a heterocyclic group, e.g., furoyl; R is wherein R is alkyl containing one to five carbon atoms, such as methyl, ethyl, propyl, butyl and pentyl, carboxy, cyano, aryl containing six to 12 carbon atoms, substituted aryl such as nitrophenyl, methoxyphenyl, ethoxyphenyl or heterocyclic such as furoyl; R is hydrogen, alkyl containing one to five carbon atoms, substituted alkyl such as oxoalkyl, carboxy and carboxyalkyl; R is hydrogen, alkyl containing one to five carbon atoms such as methyl, ethyl, propyl, butyl, tert.-.

butyl and pentyl, substituted alkyl such as hydroxymethyl, carboxy and carboxyalkyl, aryl, substituted aryl, e.g., nitrophenyl, methoxyphenyl, benzoyl; n is 0 or 2. Alkyl as employed herein includes alkyl containing substituent groups which do not adversely affect the desired stabilizing activity of the described compounds. The alkyl group can be, for example, carboxyalkyl or dicarboxyalkyl.

An especially suitable thiazole thioether is S-acetyl- 4-methyl-2-(3-oxobutylthio )thiazole ofthe formula:

wherein R is as described previously; R is alkyl containing one to five carbon atoms, aryl containing 6 to l2 carbon atoms, or furoyl; n is 0 or 2.

An especially suitable thiadiazole thioether is 4-furoyl-3-methylthio-1 ,2,4-thiadiazole-5-thione of the formula:

Other examples of suitable thiadiazole thioether stabilizer precursors which can be employed in the practice of the invention include:

4-Furoyl-3-( 3-oxobutylthio)-1 ,2,4-thiadiazole-5- I thione,

3-Me'thylthio-4-benzoyl-l ,2,4-thiadiazole-5-thione,

4-Acetyl-3-methylthio-l ,2,4-thiadiazole-5 -thione or 4-Acetyl-3-furoylethylthiol ,2,4-'thiadiazole-5- thione.

Still another suitable azole thioether stabilizer precursor which can be employed in the desired combination includes, for example, tetrazole thioethers of the formula:

wherein R is phenyl, substituted phenyl such as 2,6-dit-butyl-phenyl, alkyl or wherein R is as described previously; R, can be alkyl, especially alkyl containing one to three carbon atoms, such as methyl, ethyl and propyl, and aryl, such as phenyl; n is or 2.

An especially suitable tetrazole thioether is 2,6- ditert.-butyl-4-( l-phenyl--tetrazolyl)thiophenyl of the formula: n V

wherein R R and R and n are as described previously. An especially suitable blocked azole thione is 5- acetyl-4-methyl-3-(3-oxobutyl)thiazoline-Z-thione of the formula: v

g 8 CH- j i 0 CH -N-(OH1)1tiL-CH;

Other examples of suitable blocked thiazoline thione stabilizer precursors which can be employed in the practice of the invention include:

5-Acetyl-3-benzoyl-4-methylthiazoline-2-thione, 4-Benzoylmethyl-3-benzoylthiazoline-Z-thione, 3-Furoyl-4-hydroxymethylthiazoline-Z-thione, 3-Benzoyl'4-hydroxymethylthiazoline-2-thione, 3-Benzoyl-44ert.-butylthiazoline-Z-thione and 5 -Carboethoxy-4-methyl-3-( 3-oxobutyl )thiazoline- 2-thione.

The described stabilizer precursors are suitable in a range of concentration; however, they are especially suitable at a concentration from about 0.002 to about 0.10 mole of stabilizer precursorper mole of oxidizing agent, e.g., silver behenate, according to the invention, in an element as described. The desired concentration will'depend on several factors, such as the particular image-forming combination and other components of the element, desired image, processing temperature and the like.

A simple test may be used to determine whether or not a compound or material is functioning as an image stabilizer as described. If the compound, after incorporation in the invention as described, prevents the build-up of background density or minimum density above 0.l0 without undue stain, as in following Example 2, in comparison to a coating, as in following Example l, where the stabilizer precursor has been omitted, then the compound is considered to be a suitable stabilizer.

It is believed that the described azole thioether and blocked azole thiones are the precursors of the actual moiety, compound or material which, upon combination with undeveloped silver ions or radicals, prevent print-out due to room-light exposure and alleviate background stain. However, the exact mechanism of stabilization is not fully understood.

The azole thioethers and blocked azole thiones can be prepared by the Michael addition of 0:,B-unsaturated ketones such as methyl vinyl ketone to 4- thiazoline-Z-thione. By carefully controlling the reaction conditions, either azole thioethers or blocked azole thiones can be prepared almost exclusively of one another as described in J. Heterocyclic Chem., 6, 397-401 (1969) of Humphlett. The thermal reversibility of some of the azole thioethers formed via the Michael addition to 4-thiazoline-2-thiones is reported in Canadian J. Chem., 44, 2315-2321 (1966) of Allen et al.

Spectral-sensitizing dyes can be used conveniently to confer additional sensitivity to the light-sensitive silver halide employed in the practice of the invention. For instance, additional spectral sensitization can be obtained by treating the silver halide with asolution 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. No. 1,154,781. For optimum results, the dye can beadded tothe emulsion either as a final step or at some earlier stage.

Sensitizing dyes useful in sensitizing silver halide emulsions are described, for example, in U.S. Pat. No.

2,526,632 of Brooker et al. issued Oct. 24, 1950; U.S. Pat. No. 2,503,776 of Sprague issued Apr. 11, 1950; U.S. Pat. No. 2,493,748 of Brooker et al. issued Jan. 10, 1950; and U.S. Pat. No. 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 wither 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 thiohydantoins, rhodanines, oxazolidenediones, thiazolidenediones, barbituric acids, thiazolineones and malononitrile. These acid nuclei can be substituted with alkyl, alkylene, phenyl, carboxyalkyl, sulfoalkyl, hydroxyalkyl, alkoxyalkyl, alkylamine groups or heterocyclic nuclei. Combinations of these dyes can be used, if desired. In addition, supersensitizing addenda 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 U.S. Pat. No. 2,933,390 of McFall et al. issued Apr. 19, 1960, and U.S. Pat. No. 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 solvent solutions can be used. The compounds can be added using various procedures including, for example, those described in U.S. Pat. No. 2,912,343 of Collins et al. issued Nov. 10, 1959; U.S. Pat. No. 3,342,605 of McCrossen et al. issued Sept. 19, 1967; U.S. Pat. No. 2,996,287 of Audran issued Aug. 15, 1961; and U.S. Pat. No. 3,425,835 ofJohnson et al. issued Feb. 4, 1969.

A range of concentration of dye can be employed in the practice of the invention. The desired concentration will be influenced by the desired spectral sensitivity, other components in the system, the desired image, processing conditions and the like. Typically, a concentration of the described sensitizing dye is about 0.05 to about 1 milligram per square foot of the described photographic and thermosensitive element, usually about 0.1 milligram per square foot of dye being employed.

One embodiment of the invention is a photosensitive and thermosensitive element comprising a support, an oxidation-reduction image-forming combination comprising (i) a heavy metal salt oxidizing agent, such as a silver salt oxidizing agent, with (ii) a reducing agent, such as a bis-naphthol reducing agent, a catalyst for the described oxidation-reduction image-forming combination, e.g., photosensitive silver halide, a binder and a divalent metal salt image amplifier, e.g., zinc acetate, copper acetate or cadmium acetate. For example, the photosensitive element as described can comprise:

a. a support,

b. 2,2'-dihydroxyl ,1 '-binaphthyl reducing agent,

c. silver behenate oxidizing agent,

d. photosensitive silver halide,

e. polyvinyl butyral binder,

f. phthalimide activator-toning agent,

g. 5-acetyl-4-methyl-2-(3-oxobutylthio)thiazole image-stabilizer precursor,

h. a sensitizing dye and i. a divalent metal salt image amplifier, such as zinc acetate or cadmium acetate.

Another embodiment of the invention is a photosensitive and thermosensitive composition comprising:

a. an oxidation-reduction image-forming combination comprising (i) a heavy metal salt oxidizing agent, e.g., a silver salt oxidizing agent, with (ii) a reducing agent, e.g., a bis-naphthol reducing agent,

b. a catalyst for the described oxidation-reduction image-forming combination, e.g., photosensitive silver halide, and

c. a divalent metal salt image amplifier which is a zinc, cadmium or copper salt, as described. For example, the photosensitive and thermosensitive composition can comprise:

a. about 0.10 mole to about 2.0 moles, e.g., about 0.40 mole to about 0.75 mole, of reducing agent, such as 2,2-dihydroxy-l,l'-binaphthyl, per mole of heavy metal salt oxidizing agent, such as silver behenate oxidizing agent,

b. about 0.005 mole to about 0.50 mole of photosensitive silver salt per mole of silver behenate oxidizing agent, and

c. about 0.005 mole to about 0.20 mole, e.g., about 0.010 mole to about 0.10 mole, ofa zinc, cadmium or copper salt image amplifier per mole of silver behenate oxidizing agent.

After exposure of the described photosensitive and thermosensitive element, the resulting latent image is developed merely by heating the element. A visible image on the photosensitive and thermosensitive element can'be produced within a few seconds, e.g., about 0.5 to about 60 seconds, after exposure by heating the element to moderately elevated temperatures, e.g., about to about 250 C.

Accordingly, another embodiment of the invention IS: in a method of developing a latent image in an exposed photosensitive and thermosensitive element comprising a support, an oxidation-reduction image-forming combination comprising (i) a heavy metal salt oxidizing agent with (ii) a reducing agent, a catalyst for the described oxidation-reduction image-forming combination, a binder and a divalent metal salt image amplifier which is a zinc, copper or cadmium salt, comprising heating said element to about 80 C. to about 250 C.

A temperature range of about C. to about C is usually suitable for developing and stabilizing a desired image. 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 a few seconds, such as about 0.5 second to about 60 seconds.

The photographic process can comprise, for example, exposing to actinic radiation a photosensitive and thermosensitive element comprising a support,

a. an oxidation-reduction image-forming combination comprising: Y

i. silver behenate oxidizing agent and ii. 2,2'-dihydroxy-l ,l -binaphthyl reducing agent,

b. photosensitive silver halide,

c. a divalent metal salt such as zinc acetate,

(1. polyvinyl butyral binder,

e. phthalimide activator-toning agent,

f. an image-stabilizer precursor such as 5-acetyl-4- methyl-2-(3-oxobutylthio)thiazole and g. a sensitizing dye, and heating the described element from about 80 C. to about 250 C. for about 0.5 to about 60 seconds.

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

in some cases, if desired, an element can be prepared wherein the described silver halide can be in one layer and other components in other layers. For example, an element according to the invention can comprise a support, a layer containing photographic silver halide and a layer comprising a so-called thermosensitive processing composition comprising:

a. a heavy metal salt oxidizing agent, e.g., a silver salt oxidizing agent such as a silver salt of an organic acid,

b. a reducing agent, as described, such as a bisnaphthol reducing agent,

c. an activator-toning agent, as described, and

d. a divalent metal salt image amplifier, as described. An example of such a processing composition is a thermosensitive processing composition comprising:

a. silver behenate,

b. 2,2'-dihydroxy-l ,l -binaphthyl,

c. phthalimide and d. zinc acetate. Typically, a polyvinyl butyral binder is employed with the processing composition.

As another example, it is sometimes advantageous to incorporate the bis-B-naphtho] reducing agent and/or the zinc acetate in a polyvinyl butyral or cellulose acetate binder and to coat the resulting composition as an anti-abrasion overcoat on the element as described previously.

Various methods can be employed in providing the necessary heating of the described photosensitive and thermosensitive elements. The heating means can be a simple hot plate, iron or the like.

Other addenda are known to be useful in photosensitive and thermosensitive elements of this type, such as described in British Patent No. 1,161,777 published Aug. 20, 1969, U.S. Pat. No. 3,152,904 of Sorensen and Shepard issued Oct. 13, 1964, and U.S. Pat. No. 3,457,075 of Morgan and Shely issued July 22, 1969.

The following examples are included for a further.

understanding of the invention.

EXAMPLE 1 This is a comparative example.

A photosensitive element is prepared as follows:

A coating composition is prepared by mixing the following components:

Silver behenate 42.00 g. Behenic acid 32.00 g. Polyvinyl butyral 15.00 g. Sodium bromide (reacts with silver 0.25 g. behenate to form silver bromide in situ) Phthalimide 8.50 g. Acetone-toluene (1:1 by volume) 500 ml.

After ball-milling for about 24 hours, 72.0 milliliters of the above dispersion is combined with the following solutions:

Acetone containing 1.0 mg./ml. of 3- 0.3 ml.

background stain.

EXAMPLE 2 This illustrates the invention.

The procedure set out in Example 1 is repeated with the exception that 2.5 ml. of a methanol solution containing 1.0 percent by weight of zinc acetate is added to the final dispersion just prior to making the coating.

The final element is exposed and processed as in Example 1; the resulting image is jet-black, has a maximum density of 1.24 and a minimum density of 0.04. A 21.5

percent increase in image density is realized in comparison to Example 1.

EXAMPLE 3 This illustrates the invention.

Similar results are obtained as in Example 2 upon substitution of cadmium acetate for zinc acetate.

EXAMPLE 4 This illustrates the invention.

Similar results are obtained as in Example 2 upon substitution of cupric acetate for zinc acetate.

Although the invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, variations and modifications can be effected within the spirit and scope of the invention.

1 claim:

1. In a photosensitive and thermosensitive element comprising a support having thereon an oxidationreduction image-forming combination comprising (i) a heavy metal salt oxidizing agent with (ii) a reducing agent, a photosensitive silver salt catalyst for said oxidation-reduction image-forming combination and a binder; the improvement comprising a divalent metal salt image amplifier which is a zinc, copper or cadmium salt.

2. A photosensitive and thermosensitive element comprising a support having thereon a. an oxidation-reduction image-forming combination comprising (i) a silver salt oxidizing agent and (ii) a bis-beta-napthol reducing agent,

b. a catalyst for said oxidation-reduction imageforming combination comprising photosensitive silver halide,

c. a divalent metal salt image amplifier which comprises zinc acetate and d. a binder.

3. A photosensitive and thermosensitive element as in claim 2 also comprising an activator-toning agent.

4. A photosensitive and thermosensitive element as in claim 2 also comprising an activator-toning agent which is phthalimide.

5. A photosensitive and thermosensitive element as in claim 2 also comprising a stabilizer precursor which is an azole thioether or a blocked azole thione.

6. A photosensitive and thermosensitive element as in claim 2 also comprising a stabilizer precursor which is 5 -acetyl-4-methyl-2-( 3-oxobuty1thio )thiazole.

7. A photosensitive and thermosensitive element comprising a support having thereon a. an oxidation-reduction image-forming combination comprising (i) an oxidizing agent comprising silver behenate and (ii) a reducing agent which is 2,2'-dihydroxy-1,1'-binaphthyl,

b. photosensitive silver halide,

c. a divalent metal salt image amplifier which is zinc acetate,

d. polyvinyl butyral binder,

e. phthalimide activator-toning agent, and

f. a sensitizing dye.

8. A photosensitive and thermosensitive element as in claim 2 also comprising a sensitizing dye.

9. A photosensitive and thermosensitive element as in claim 2 comprising a support having thereon a. about 0.10 mole to about 2.0 moles of said reducing agent per mole of said catalyst,

b. about 0.005 mole to about 0.50 mole of said catalyst per mole of said oxidizing agent and c. about 0.005 mole to about 0.20 mole of said zinc acetate per mole of said oxidizing agent.

10. A photosensitive and thermosensitive composition comprising:

a. an oxidation-reduction image-forming combination comprising (i) a heavy metal salt oxidizing agent with (ii) a reducing agent,

b. a photosensitive silver salt catalyst for said oxidation-reduction image-forming combination and c. a divalent metal salt image amplifier which is a zinc, copper or cadmium salt.

11. A photosensitive and thermosensitive composition comprising:

a. an oxidation-reduction image-forming combination comprising (i) a silver salt oxidizing agent with (ii) a bis-beta-naphthol reducing agent,

b. a catalyst for said oxidation-reduction imageforming combination comprising photosensitive silver halide and c. a divalent metal salt image amplifier which com-' prises zinc acetate.

12. A photosensitive and thermosensitive composition as in claim 11 also comprising an activator-toning agent.

13. A photosensitive and thermosensitive composition as in claim 11 also comprising an activator-toning agent which is phthalimide.

14. A photosensitive and thermosensitive composition as in claim 11 also comprising a stabilizer precursor which is an azole thioether or a blocked azole thione.

15. A photosensitive and thermosensitive composition comprising:

a. an oxidation-reduction image-forming combination comprising (i) an oxidizing agent comprising silver behenate and (ii) a reducing agent which is 2,2'-dihydroxy-l,l'-binaphthyl,

b. photosensitive silver halide,

c. a divalent metal salt image amplifier which is zinc acetate,

d. polyvinyl butyral binder,

e. phthalimide activator-toning agent,

f. an image-stabilizer precursor comprising S-acetyl- 4-methyl-2--(3-oxobutylthio)thiazole and g. a sensitizing dye.

16. A photosensitive and thermosensitive composition as in claim 11 also comprising a sensitizing dye.

17. A photosensitive and thermosensitive composition as in claim 11 comprising:

a. about 0.10 mole to about 2.0 moles of said reducing agent per mole of said oxidizing agent,

b. about 0.005 to about 0.50 mole of said catalyst per mole of said oxidizing agent and c. about 0.005 mole to about 0.20 mole of said zinc, copper or cadmium salt per mole of said oxidizing agent.

18. A method of developing an image in an exposed photosensitive and thermosensitive element comprising a support having thereon an oxidation-reduction image-forming combination comprising (i) a heavy metal salt oxidizing agent with (ii) a reducing agent, a

photosensitive silver salt catalyst for said oxidationreduction image-forming combination, a binder and a divalent metal salt image amplifier which is a zinc, copper or cadmium salt, comprising heating said element to about C to about 250 C. i

19. A method of developing and stabilizing an image in an exposed photosensitive and thermosensitive element comprising a support,

a. an oxidation-reduction image-forming combination comprising (i) a silver salt oxidizing agent and (ii) a bis-beta-naphthol reducing agent,

c. a divalent metal salt image amplifier which comprises zinc acetate, a binder, e. an activator-toning agent and f. an image-stabilizer precursor which is an azole thioether or a blocked azole thione, comprising heating said element to about 80 C. to about 250 C. e 20. A method of developing and stabilizing an image in an exposed photosensitive and thermosensitive element comprises a support, having thereon a. an oxidation-reduction image-forming combination comprising (i) an oxidizing agent comprising silver behenate and (ii) a reducing agent comprising 2,2'-dihydroxy-l ,l '-binaphthyl,

b. photosensitive silver halide,

c. a divalent metal salt image amplifier which is zinc acetate,

d. polyvinyl butyral binder,

e. phthalimide activator-toning agent,

f. an image-stabilizer precursor comprising S-acetyl- 4-methyl-2-(3-oxobutylthio)thiazole and g. a sensitizing dye, comprising heating said element to about 80 C. to about 250 C.

21. A method as in claim 20 comprising heating said element for about 0.5 to about 60 seconds.

22. A thermosensitive processing composition comprising:

a. a silver salt oxidizing agent,

b. a bis-beta-naphthol reducing agent,

c. an activator-toning agent and d. a divalent metal salt image amplifier.

23. A thermosensitive processing composition comprising:

a. silver behenate,

b. 2,2'-dihydroxy-l,l '-binaphthyl,

c. phthalimide and d. zinc acetate.

24. A thermosensitive processing composition as in claim 22 comprising polyvinyl butyral binder.

25. The photosensitive and thermosensitive element of claim 1 wherein said divalent metal salt image amplifier is present in a concentration of about 0.005 mole to about 0.20 mole of said divalent metal salt image amplifier per mole of said oxidizing agent.

26. The photosensitive and thermosensitive composition of claim 10 wherein said divalent metal salt image amplifier is present in a concentration of about 0.005 mole to about 0.20 mole of said divalent metal salt image amplifier per mole of said oxidizing agent.

Claims

2. A photosensitive and thermosensitive element comprising a support having thereon a. an oxidation-reduction image-forming combination comprising (i) a silver salt oxidizing agent and (ii) a bis-beta-napthol reducing agent, b. a catalyst for said oxidation-reduction image-forming combination comprising photosensitive silver halide, c. a divalent metal salt image amplifier which comprises zinc acetate and d. a binder.
3. A photosensitive and thermosensitive element as in claim 2 also comprising an activator-toning agent.
4. A photosensitive and thermosensitive element as in claim 2 also comprising an activator-toning agent which is phthalimide.
5. A photosensitive and thermosensitive element as in claim 2 also comprising a stabilizer precursor which is an azole thioether or a blocked azole thione.
6. A photosensitive and thermosensitive element as in claim 2 also comprising a stabilizer precursor which is 5-acetyl-4-methyl-2-(3-oxobutylthio)thiazole.
7. A photosensitive and thermosensitive element comprising a support having thereon a. an oxidation-reduction image-forming combination comprising (i) an oxidizing agent comprising silver behenate and (ii) a reducing agent which is 2,2''-dihydroxy-1,1''-binaphthyl, b. photosensitive silver halide, c. a divalent metal salt image amplifier which is zinc acetate, d. polyvinyl butyral binder, e. phthalimide activator-toning agent, and f. a sensitizing dye.
8. A photosensitive and thermosensitive element as in claim 2 also comprising a sensitizing dye.
9. A photosensitive and thermosensitive element as in claim 2 comprising a support having thereon a. about 0.10 mole to about 2.0 moles of said reducing agent per mole of said catalyst, b. about 0.005 mole to about 0.50 mole of said catalyst per mole of said oxidizing agent and c. about 0.005 mole to about 0.20 mole of said zinc acetate per mole of said oxidizing agent.
10. A photosensitive and thermosensitive composition comprising: a. an oxidation-reduction image-forming combination comprising (i) a heavy metal salt oxidizing agent with (ii) a reducing agent, b. a photosensitive silver salt catalyst for said oxidation-reduction image-forming combination and c. a divalent metal salt image amplifier which is a zinc, copper or cadmium salt.
11. A photosensitive and thermosensitive composition comprising: a. an oxidation-reduction image-forming combination comprising (i) a silver salt oxidizing agent with (ii) a bis-beta-naphthol reducing agent, b. a catalyst for said oxidation-reduction image-forming combination comprising photosensitive silver halide and c. a divalent metal salt image amplifier which comprises zinc acetate.
12. A photosensitive and thermosensitive composition as in claim 11 also comprising an activator-toning agent.
13. A photosensitive and thermosensitive composition as in claim 11 also comprising an activator-toning agent which is phthalimide.
14. A photosensitive and thermosensitive composition as in claim 11 also comprising a stabilizer precursor which is an azole thioether or a blocked azole thione.
15. A photosensitive and thermosensitive composition comprising: a. an oxidation-reduction image-forming combination comprising (i) an oxidizing agent comprising silver behenate and (ii) a reducing agent which is 2,2''-dihydroxy-1,1''-binaphthyl, b. photosensitive silver halide, c. a divalent metal salt image amplifier which is zinc acetate, d. polyvinyl butyral binder, e. phthalimide activator-toning agent, f. an image-stabilizer precursor comprising 5-acetyl-4-methyl-2-(3-oxobutylthio)thiazole and g. a sensitizing dye.
16. A photosensitive and thermosensitive composition as in claim 11 also comprising a sensitizing dye.
17. A photosensitive and thermosensitive composition as in claim 11 comprising: a. about 0.10 mole to about 2.0 moles of said reducing agent per mole of said oxidizing agent, b. about 0.005 to about 0.50 mole of said catalyst per mole of said oxidizing agent and c. about 0.005 mole to about 0.20 mole of said zinc, copper or cadmium salt per mole of said oxidizing agent.
18. A method of developing an image in an exposed photosensitive and thermosensitive element comprising a support having thereon an oxidation-reduction image-forming combination comprising (i) a heavy metal salt oxidizing agent with (ii) a reducing agent, a photosensitive silver salt catalyst for said oxidation-reduction image-forming combination, a binder and a divalent metal salt image amplifier which is a zinc, copper or cadmium salt, comprising heating said element to about 80* C to about 250* C.
19. A method of developing and stabilizing an image in an exposed photosensitive and thermosensitive element comprising a support, a. an oxidation-reduction image-forming combination comprising (i) a silver salt oxidizing agent and (ii) a bis-beta-naphthol reducing agent, b. a catalyst for said oxidation-reduction image-forming combination comprising photosensitive silver halide, c. a divalent metal salt image amplifier which comprises zinc acetate, d. a binder, e. an activator-toning agent and f. an image-stabilizer precursor which is an azole thioether or a blocked azole thione, comprising heating said element to about 80* C. to about 250* C.
20. A method of developing and stabilizing an image in an exposed photosensitive and thermosensitive element comprises a support, having thereon a. an oxidation-reduction image-forming combination comprising (i) an oxidizing agent comprising silver behenate and (ii) a reduciNg agent comprising 2,2''-dihydroxy-1,1''-binaphthyl, b. photosensitive silver halide, c. a divalent metal salt image amplifier which is zinc acetate, d. polyvinyl butyral binder, e. phthalimide activator-toning agent, f. an image-stabilizer precursor comprising 5-acetyl-4-methyl-2-(3-oxobutylthio)thiazole and g. a sensitizing dye, comprising heating said element to about 80* C. to about 250* C.
21. A method as in claim 20 comprising heating said element for about 0.5 to about 60 seconds.
22. A thermosensitive processing composition comprising: a. a silver salt oxidizing agent, b. a bis-beta-naphthol reducing agent, c. an activator-toning agent and d. a divalent metal salt image amplifier.
23. A thermosensitive processing composition comprising: a. silver behenate, b. 2,2''-dihydroxy-1,1''-binaphthyl, c. phthalimide and d. zinc acetate.
24. A thermosensitive processing composition as in claim 22 comprising polyvinyl butyral binder.
25. The photosensitive and thermosensitive element of claim 1 wherein said divalent metal salt image amplifier is present in a concentration of about 0.005 mole to about 0.20 mole of said divalent metal salt image amplifier per mole of said oxidizing agent.
26. The photosensitive and thermosensitive composition of claim 10 wherein said divalent metal salt image amplifier is present in a concentration of about 0.005 mole to about 0.20 mole of said divalent metal salt image amplifier per mole of said oxidizing agent.
27. The method of claim 18 wherein said divalent metal salt image amplifier is present in a concentration of about 0.005 mole to about 0.20 mole of said divalent metal salt image amplifier per mole of said oxidizing agent.