Latent image photographic system

Abstract

This invention relates to compositions which are sensitive to light and suitable for photography and photographic reproduction purposes. More particularly, the invention relates to the production of stable, colored print-out and developable-out images produced by exposing to light, and to light and heat, combinations of aryl amines, halogenated hydrocarbon compounds, and N-vinyl compounds disposed in a suitable base.

I claim: 
     
       1. A dry photographic film suitable for the production of visible images by exposure to a combination of light and heat, comprising (I) a film-forming plastic selected from the group consisting of cellulose derivatives and addition polymers; (II) an N-vinyl compound selected from the group consisting of N-vinylamines, N-vinylamides and N-vinylimides; and (III) a halogenated hydrocarbon compound selected from the group of compounds which produces free radicals upon exposure to light of a suitable wave length and in which there is present at least one active halogen selected from the group consisting of chlorine, bromine and iodine which is attached to a carbon atom having not more than one hydrogen atom attached thereto; there being between 0.1 and 2 parts by weight of N-vinyl compound and between 0.1 and 2 parts by weight of halogenated hydrocarbon per part of film-forming plastic, by weight. 
     
     
       2. The composition of claim 1 containing in addition up to 1 part by weight of an arylamine other than an N-vinylamine, per part of film forming plastic by weight. 
     
     
       3. The composition of claim 1 containing in addition up to 0.3 part by weight of a fixing agent selected from the group consisting of thioureas, thioamides, thiols, thioanilides, thiocarbazides and zinc sulfide, per part of film forming plastic. 
     
     
       4. The composition of claim 1 containing in addition between 0.005 and 0.01 part by weight of a sensitizer to visible light, per part of plastic. 
     
     
       5. The composition of claim 1 in which the halogenated hydrocarbon has an energy of formation of the free halogen radical of not less than forty kilogram calories per mol. 
     
     
       6. The composition of claim 1 in which the plastic is selected from the group consisting of ethyl cellulose, polyvinylchloride, polystrene, chlorinated rubber, polyvinylacetate, polymethylmethacrylate, cellulose acetate, copolymer of vinyl chloride and vinylidene chloride, and cellulose nitrate. 
     
     
       7. The composition of claim 1 wherein the halogenated hydrocarbon compound is selected from the group consisting of carbon tetrabromide, iodoform, hexachlorethane, hexachlorbenzene, tetrabrombutane and tetrachlortetrahydronaphthalene. 
     
     
       8. The composition of claim 1 containing in addition between 0.25 and 1.0 parts of a plasticizer per part by weight of plastic. 
     
     
       9. The composition of claim 2 wherein the aryl amine is selected from the group consisting of diphenylamine, dibenzylamine, triphenylamine, diphenyguanidine, triphenylguanidine, N-N'-dialkylanilines, and mixtures of aniline, paratoluidine and orthotoluidine. 
     
     
       10. The composition of claim 2 wherein the arylamine is diphenylamine, the N-vinyl compound is N-vinylcarbazole, the halogenated hydrocarbon compound is carbon tetrabromide, and the film-forming compound is ethyl cellulose. 
     
     
       11. A method of photographically producing a visible image which comprises preparing a film having the composition of claim 1 and exposing the film sequentially to a combination of light and thermal radiation, at least one of said exposures being an image-forming exposure and the other being a blanket exposure. 
     
     
       12. A method of developing visible images which comprises preparing the composition of claim 1 in a solvent for the film-forming plastic; depositing said composition on a support; evaporating said solvent, leaving a film consisting of a dispersion of the several ingredients in the film-forming plastic on said support; each of said processes prior to the formation of said film being conducted in the absence of radiation to which the composition exhibits a sensitivity, and exposing selected portions of the resulting article to light, whereby a reaction occurs to form a non-visible latent image in said film and thereafter producing a visible image by exposing said latent image to thermal radiation. 
     
     
       13. A method of developing visible photocopies which comprises preparing the composition of claim 1 in a solvent for the film-forming plastic; depositing said composition on a transparent support; evaporating said solvent, leaving a photosensitive film on said support; and exposing the entire surface of the resulting article to light, placing a sheet bearing an image to be copied adjacent to said sensitized exposed photosensitive film, and subjecting the presensitized film and image to be copied to heat to develop a duplicate of the desired image. 
     
     
       14. An article comprising the composition of claim 1 supported on a base. 
     
     
       15. The article of claim 14 wherein the base is transparent. 
     
     
       16. The article of claim 14 wherein the base is paper. .Iadd. 17. Light-sensitive material comprising a suitable support and a light-sensitive coating thereon, said coating comprising the dried residue of a homogeneous solution in a suitable solvent, said residue comprising: a. a leuco triaryl methane dye, selected from the group consisting of leuco crystal violet, leuco malachite green, fuchsine base, leuco pararosaniline;   b. an N-vinyl carbazole, selected from the group consisting of N-vinyl carbazole and its alkyl derivatives; and   c. a halogen hydrocarbon which splits off halogen when exposed to light, said halogen hydrocarbon having the general formula: ##EQU1## wherein X represents chlorine, bromine or iodine, and R, R 1  and R 2  are the same or are different and represent chlorine, bromine, iodine, hydrogen, alkyl, aryl, aralkyl, alkenyl or a heterocyclic group.   
     
     
        .Iaddend..Iadd. 18.  Light-sensitive material according to claim 17, wherein said composition includes a binder material selected from the group consisting of natural and synthetic resins. .Iaddend..Iadd. 19. Light-sensitive material according to claim 17, wherein said composition includes a binder material selected from the group consisting of natural and synthetic resins having substantial solubility in both an organic and an aqueous alkaline solution. .Iaddend. .Iadd. 20. Light-sensitive material according to claim 17, wherein said halogen hydrocarbon is selected from the group consisting of: tetrabromomethane. .Iaddend..Iadd. 21. Light-sensitive material according to claim 17, wherein said composition comprises: a. leuco crystal violet,   b. N-vinyl carbazole, and   c. tetrabromomethane. .Iaddend.