US3030207A

US3030207A - Photographic processes

Info

Publication number: US3030207A
Application number: US733702A
Authority: US
Inventors: Edwin H Land
Original assignee: Polaroid Corp
Current assignee: Polaroid Corp
Priority date: 1952-07-17
Filing date: 1958-05-07
Publication date: 1962-04-17
Anticipated expiration: 1979-04-17

Description

April 17, 1962 E. H. LAND 3,030,207

PHOTOGRAPHIC PROCESSES Original Filed July 17, 1952 I8 24 34 2e 1 22 32 4o "1 l'lllllll'lI/I l \l .I' 20) FIG I I lNVENTOR ATTORNEYS United States ..short useful life.

sheet, are relatively .unstable. ,many compositions intended to hypersensltize or to opti- 3,039,207 4 PrtoiooRAPn-rc rnocnssns Edwin H. Land, Cambridge,-Mass., assignor to Polaroid 'Corporation, Cambridge, Mass., a corporation of Delaware Original application July 17, 1952,8er. :No.*299,358 npw Patent No. 2,846,399,;iated Aug. 5, 13 58. Divided andthis appiication May 7, 1958, Ser. No. 733,702

' 6 Claims. (Ci. 962) This invention relates to photography. andmoreparticularly to photographic processes.

The present invention is a division of copending appl1- cation Serial No. 299,358, filed July 17, 1952 (now Patent No. 2,846,309, issued August 5, 1958).

It is recognized in the art that many a photographic composition, once coated on or otherwise applied to the surface of a sheet intended to bephotoe zposed, has a For example, certain photosensitive compositions, once coated on the Surface of a support Similarly, once 7 applied,

cally sensitize photosensitive coatings are able to effectivelyperform their respective functions only for a short period. Furthermore, many photosensitive coatings are mixtures of distinct components intended to react with 2 each other only when photoexposed but nevertheless tending to react with each otherthough not photoexposed. It

.is frequently desired, therefore, that a photographiccomposition .be applied to the surface of asheet only shortly before the sheet is photoe rposed.

.An object of the present invention is to provide processes utilizing rupturable protective containers which -car rya photographiccomposition of the aforementioned type, or atleast one of its components, so thatit-is capableof being readilyapplied to thesurface of a sheet when I desired.

Another object-of the-present invention is to provide a process in whichgthere isassociated with such a con- ,tainer at least an additional rupturable-protective con- .tainer carrying at least another photographic composition also capable of being readily applied whendesired, the

containers. being,so constructed and arranged as to be capable of sequentially discharging their contents for spreading on the surface of a sheet where they are adapted to perform related functions.

:Stillotherobjectsof the invention are: to provide a process utilizing a photographic assemblage comprising a sheet'and atleast a-container associated withqavsu face thereof, the .container carrying a photographic composition and, uponapplication of opposed compressional forces thereto,b eing capable of rfilfiflsing the photographic composition therefrom-for spreading on the surface, the

photographic composition beingassociated with; the photosensitivity of the. sheet; to provide a process; utilizing a photographic, assemblage comprising a sheet and at least a pair of containers associated with a surface of the sheet, one container carrying a-, photogr aphic composition re- "lated to the photosensitivity of the; sheen-the othercon- :tainer carrying another photographic composition, the

containers being so constructed and arranged as to be capable of sequentially discharging their contents on the surface where they .are adaptedto perform related functions; and to provide a process utilizing an assemblage of this type having associated therewith means forpermitting the application of opposedcompressional forcesto one container of the .pair while preventing theapplication of opposed compressional forces to the; other container of the pair.

, Eurther objects of the present invention arez to-provide apmce s utiliz ng ana sembl se 9s i h e having associated therewith containers carrying different 3,030,207- Patented Apr. 17, 1 962 ice photographic compositions that are, capable f segneny p r or n fl en snctiw th asse b as t provide a pr ce uti i in in n a sem e, o the foregoing type a plurality.of containers, each container being adapted to dischargethe photographic, composition therewithin when opposed compressional forces are applied thereto; to provide a process ptilizing a photographic assemblage comprising a first sheet and a second sheet, the sheets being adapted to be superposed with a surface of the first sheet and a surface of thesecond sheet in contiguous relation at leasta pair of photographic composition containers secured to at least one of ;the surfaces, one container of the pairbeing adjacentto the other container of the pair at least when the sheets-.are superposed, the containers, upon application ofmechanical stress thereto, being adapted 'to discharge their-contents, and means associated with the containers for permittingthe application of opposed compressional forces to one container of thepair while preventing the application of opposed compressional forces tothe other'l'container of the pair, whereby sequential discharge of the container contentsmaybe accomplishedgand to. provide a process utilizing a means for permitting'the application of opposed compressional forces to one container ofthe pair while preventingthe application. of opposed compressional forces to the other container of .the pair that portion of one of the containers of the pair. being substantially a predetermined distance from,a;first of apair; of

sheets of the foregoing type,. t his means including at least a crush-resistant element, which provides: a portiondhat is adapted toabut against asecondofthe pair of sheets andthat is spacedfrom the first of the pair of sheetsby a distance at least. substantially. as great as the predeten mined distance.

7 Still :further objects of the present invention are:; to provide a photographicprocess comprisingthe steps of superposing a first sheet on a secondsheet with; a surface of the first sheet and. a-surface. of the second sheet in' contiguous relation and spreading a photographic composition betweenthe surfaces, the photographic composition being related to the photosensitivityof at leastone-of the sheets;.to provide aphotographic process comprising the steps of superposing afir st sheet on a second sheet .with a" surface of the first. sheet and a surface of the second sheetin contiguous relation, spreading a first photographic composition between the surfaces, 'photoexposing atleast one ofthesurfacesandthereafter, spreading a-second phoftographic cornpositionbetween the surfaces; and toproing detailed disclosure, and the -scope;of the application of which will be indicated in {the claims.

For a fuller understending, of the nature and objects of the invention, referenceshould-be had to the, following detailed description taken in connection rwith -theaccompanying drawing wherein:

FEGURE lis an;exaggerated-sectional.viewcofsan .as-

I sem blage embodyingthe present inyention;

' FIG. Zisan exaggerated perspective-view of the'assemblage ofFiG. 1, shown-inconjunetionwith cooperating pressure-applying means; and

on opposite sides of the assemblage.

FIG. 3 is an exaggerated sectional view of another assemblage embodying the present invention.

With reference now to the drawing, wherein like numerals denote like parts, FIGS. 1 and 2 illustrate generally the physical structure of one example of a photographic assemblage, herein designated at 18, embodying the present invention. Generally, this assemblage comprises a pair of sheets 21 and 22 which are adapted to be superposed with their adjacent surfaces in contiguous relation, that is, with their surfaces either close to or in contact with each other. A pair of

adjacent containers

24 and 26 are secured to sheet 20, container 24 carrying a predetermined quantity of a photosensitive composition and container 26 carrying a predetermined quantity of a processing composition. These compositions are adapted to perform related functions when spread sequentially between (FIG. 2) a frame 28 of sheet 20 and an area 30 of sheet 22.

Container 24, when deformed by opposed compressional forces, is capable of releasing its contents through a rupturable mouth 32 for spreading between frame 28 and area 30. Similarly, container 26, when deformed by pposed compressional forces, is capable of releasing its contents through a rupturable mouth 34 for spreading between frame 28 and area 36. It is to be noted that container 26 is shorter in length than container 24 and that mouth 34 of container 26 overlaps an edge of container 24. By virtue of this construction, container 26 is capable of discharging its contents from mouth 34 evenly and without obstruction.

Means are provided for enabling the sequential application of opposed compresisonal forces to

containers

24 and 26 and the sequential spreading of their contents between frame 28 and area 30. In the form shown, this means includes a pair of'crush-resistant, relatively

incompressible elements

40, 40 secured to sheet adjacent to the opposite ends of container 26. The portions of these elements farthest from sheet 20 are spaced from it by a dis- 'tance at least substantially as great as the height, with respect to sheet 20, as is the processing composition-carrying portion of container 26.

The sequential application of opposed compressional forces to

containers

24 and 26, together with the sequential spreading of their contents, may be accomplished by unidirectional movement of the assemblage with respect to such pressure-applying means as two pairs of

rollers

36, 36 and 38, 38, the rollers of each pair being positioned

Rollers

36, 36 are provided with comparatively long, cylindrical, pressureapplying surfaces,

rollers

38, 38 with comparatively short ones. Elements 40, 48 are spaced from each other by a distance less than the length of the pressure-applying surfaces of

rollers

36, 36 and greater than the length of the pressure-applying surfaces of

rollers

38, 38. Thus, as the assemblage advances unidirectionally between

rollers

36, 36 and 38, 38, elements 4-0, 40 prevent

rollers

36, 36 from compressing container 26,

permit rollers

36, 36 to compress container 24 and

permit rollers

38, 38 to compress container 26.

Crush-

resistant elements

40, 40 are composed of any suitable rnaterial having a high Youngs modulus, such as stiff cardboard or synthetic resin, the elements being at least substantially as great in height with respect to sheet 20 as is the photosensitive composition-carrying portion of container 26.

Elements

40, 40 may be either integral with sheet 20 or distinct from it in accordance with the teachings of copending application Serial No. 141,905, filed by Edwin H. Land on February 2, 1950, for Image- Receiving Photographic Element Combined With a Procto one of sheets 20 a'nd22, container 26 is affixed to the other of the sheets, and

elements

40, 40 are affixed to either one or the other of the sheets. Alternatively, container 24, container 26 and

elements

40, 40 all are affixed to sheet 22. Or container 24 and container 26 are afiixed to one of sheets 2%} and 22 and

elements

40, 40 are affixed to the other of the sheets. In other alternative embodiments of assemblage 18, each of

elements

40, 40 includes two sections, one section of which is aflixed to sheet 20 and the other section of which is secured to sheet 22, these sections being adapted to abut against each other in order to prevent deformation of the container with which they are associated when

sheets

20 and 22 are superposed.

In the operation of assemblage 18,

sheets

20 and 22 are superimposed and the assemblage advanced between

rollers

36, 36 in order to rupture container 24 and to spread its photosensitive composition between frame 28 and area 38 to form a photosensitive coating. Sheets 20 and'22 now are maintained in superposed relation for a predetermined period during which the photosensitive coating becomes securely bonded to the surface of sheet 28. V The photosensitive coating now is exposed to actinic radiation in order to produce a latent image in frame 28. Thereafter, superposed

sheets

28 and 22 are advanced between

rollers

38, 38 in order to rupture container 26 and to spread its processing composition between the photosensitive coating and sheet 22.

Sheets

28 and 22 now are maintained in superposed relation for a predetermined period in order to process the latent image in frame 28 and to form a visible print. The length of the period during which the sheets are superposed following spreading of the photosensitive composition between them and the length of the period during which the sheets are superposed following spreading of the processing composition between them depend upon the specific characteristics of the photosensitive and processing compositions, as will be apparent to persons skilled in the art.

In a preferred form of assemblage 18, the photosensitive composition within container 24 includes a ripened photosensitive silver halide emulsion in the form of a gel which is fluid enough under ambient conditions to be readily spread. In such an emulsion, one or more of the silver halides, of which silver chloride, silver bromide and silver iodide are examples, are dispersed in a suitable protective colloid material such as gelatin, agar, albumen, casein, collodion or a cellulose ester. Examples of specific formulations of conventional emulsions suitable for such use are described in T. T. Baker, Photographic Emulsion Technique, American Photographic Publishing Co., Boston, 1948, chapter IV.

The emulsion within container 24, when spread between

sheets

28 and 22, forms a thin emulsion coating capable of receiving a latent image. Sheet 20, sheet 22 and this emulsion are so constituted that the adhesive forces between the emulsion coating and sheet 20 are greater than those between the emulsion coating and sheet 22, this arrangement being such as to facilitate stripping of the emulsion coating from sheet 22 when the processing composition within container 26 is spread between them. Sheet 20, for example, is composed of a paper at least one surface of which has been sized with a suitable materialsuch as hardened gelatin or baryta in gelatin. Alternatively, sheet 20 is composed of a plastic material, for

example cellulose nitrate or one of the organic acid cellulose esters such as cellulose acetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate or cellulose acetate butyrate. The surface of sheet 20 in the latter case, in order to insure good adhesion between it and the emulsion coating, is treated as, for example, with a mixture of gelatin and cellulose nitrate. Sheet 22, for example, is composed of a plastic material of the type mentioned above in reference to sheet 20.

In the preferred form of assemblage 18, either of

sheets

20 and 22 is transparent so as to permit actinic radiation to pass through it in order to form a latent image in the compositions immediately before they are used.

exposed diazonium compound to form a dye. The processing composition further includes either an alkali or an acid capable of providing the chemical environment necessary for combination of the exposed or unexposed diazonium compound and the coupler. Sheet 20 here may be composed of a suitable paper the surface of which is adapted to absorb a solution of the photosensitive diazonium compound. Or, sheet 20 may have laminated to it a suitable colloid material which is adapted to imbibe such a solution. Suitable photosensitive diazonium compounds, for example, are prepared by treating aromatic amines with nitrous acid at low temperature. As suitable couplers, mention may be made of phenols, naphthols and amino compounds which are adapted to combine with an exposed or unexposed diazo compound to form a visibly distinguishable azo dye.

This form of the invention may be modified so that the photographic composition within container 24 includes a coupler as well as a photosensitive diazonium compound. In such a case the developing composition within container 26 includes merely an alkali or an acid capable of providing the chemical environment necessary for combination of the coupler and either the exposed or unexposed diazonium compound.

Examples of specific formulations of conventional diazonium photosensitive and processing compositions suitable for use in an assemblage of the foregoing type are given in Baker, supra, pages 277-278, in L. P. Clerc, Photography, Theory and Practice, Pitman, New York,

1937, page 444, and in I. S. Friedman, History of Color Photography, American Photographic Publishing Co, Boston, 1944, pages 487-493.

FIG. 3 illustrates in detail the structure and operation of another assemblage, generally indicated by 42, embodying the present invention, like components of assemblage 42 being designated by the same numerals which designate like components in assemblage 18. Assemblage 42, in accordance with the present invention, makes practicable the intermingling of at least two photographic y means ofassemblage 42, a hypersensitizing or optical sensitizing composition may be applied to a photosensitive coating immediately before it is photoexposed. Alternatively, by means of assemblage 42, mixtures of distinct components of a photosensitive composition which are not intended to participate in a given chemical reaction until photoexposed may be maintained in separate locations until immediately before being photoexposed.

Generally, assemblage 42 includes a pair of

sheets

20 and 22, a pair of

containers

24 and 26 and a pair of crush-

resistant elements

40, 40, components which are generally similar to their counterparts in assemblage 18. Here, however, sheet 20 has laminated to one of its surfaces a coating 44, which includes at least one component of a photosensitive composition. A photosensitizing composition, which includes either another component of the photographic composition or a photosensitizing agent capable of modifying the characteristics of the photographic composition, is carried in container 24 so as to be capable of being readily spread on the surface of coating 44. Another photographic composition, for example a processing composition, is carried within container 26.

In the operation of assemblage 42, sheets 2%) and 22 are superposed and the assemblage advanced between

rollers

36, 36 in order to rupture container 24 and to spread its sensitizing composition between frame 28 and area 30.

Sheets

26 and 22 now are maintained in superposed relation for a predetermined sensitizing period. In certain forms of assemblage 42, at this point, sheet 20 is stripped from sheet 22 and dried. Coating 44 is now exposed to actinic radiation in order to produce a latent image in frame 28. Thereafter, superposed

sheets

20 and 22 are advanced between

rollers

38, 38 in order to rupture container 26 and to spread its processing composition between photosensitive coating 44 and sheet 22.

Sheets

20 and 22 now are maintained in superposed relation for a predetermined processing period during which a visible print is formed. The lengths of the predetermined sensitizing and processing periods are dependent upon the specific characteristics of coating 44 and of the photosensitizing and processing compositions, as will be apparent to persons skilled in the art.

In one form of assemblage 42, coating 44 includes a conventional silver halide emulsion the spectral sensitivity characteristics of which it is desired to modify, container 24 carries an optical sensitizing composition and container 26 carries a silver halide processing composition such as one of the processing compositions previously described. The optical sensitizing composition, for example, includes an extremely weak solution of a suitable dye in alcohol and/or water. As examples of suitable dyes, mention may be made of derivatives of fluorescein, such as erythrosine and eosine, and of various cyanines such as thiazole, thiazoline, pyridine, benzoxazole, benzothiazole, benzoselenazole, 3,3 dimethylindolenine, naphtho (2,1) thiazole, and naphtho (1,2) thiazole. Further examples of specific formulations of conventional optical sensitizing compositions suitable for use in an assemblage of the foregoing type are described in Baker, supra, chapter VI.

In a modification of this form of assemblage 42, container 24 carries a hypersensitizing composition rather than an optical sensitizing composition. Such a hypersensitizing composition, for example, includes any one of ammonia, a thiourea such as palmityl thiourea or styrene fumaryl allyl thiourea, allyl isothiocyanate, thiazole, quinoline and pyridine. The hypersensitizing composition alternatively consists merely of distilled water. Further examples of specific formulations of conventional hypersensitizing compositions suitable for such use are more fully described in Baker, supra, chapter XV.

In an alternative form of assemblage 42, coating 44 includes a material capable, after being treated with a suitable dichromate solution, of becoming differentially insolubilized or tanned when photoexposed. The various regions of such a differentially insoluble coating are capable of forming a visible print by differentially absorbing a suitable coloring material. Coating 44, for example, includes a hydrophilic colloid material such as gelatin, glue or gum arabic. Here the sensitizing composition within container 24 includes, for example, a dichrom-ate solution such as an aqueous solution of chrome alum, potassium dichromate or ammonium dichromate. The processing composition within container 26 includes a coloring material such as a water-soluble dye. Examples of specific formulations of conventional dichromate materials suitable for such use are described in Clerc, supra, pages 434-437 and page 419, section 645.

Many chromate colloid materials are photoexposed most effectively when dry. If such materials are employed in the foregoing form of assemblage 42, following the spreading of the chromate solution between

sheets

20 and 22, sheet 20, before being exposed, is stripped from sheet 22 and dried.

Preferably though not necessarily, the photographic compositions carried by

containers

24 and 26 are relatively viscous so as to be easily controlled when spread. If desired, the viscosity of any of these compositions can be increased by including within it a suitable thickener, for example, a polymeric material such as a watersoluble cellulosic material, an insoluble emulsifiable oil, a starch or a gum.

It is to be expressly understood that assemblages of the herein disclosed type may be provided with more than two rupturable containers and that more than one of these containers may be provided with crush-resistant elements of the herein disclosed type. For use in color photography, for example, such an assemblage in one form comprises three rupturable protective containers,

theifirst container 'car'rying' a conventional composition 'which includesa'red sensitive' emulsion and a cyan coupler, the second container carrying a conventional composition which includes a' green sensitive emulsion and 'a ma'gen'ta 'coupler, and the-"third container carrying a conventional 'comp'ositionfwhich includes a blue-sensitive emulsion and a-yellow coupler.

7 7 These 'containers are arranged respect 'to" a supportsheet in association with'crush-resistant' elements of the herein disclosed type blue-sensitive emulsion isspread on the se'cond separation layerto form a'thi'rd separation layer'whieh-then is photoeirpos'ed'thro'ugh a suitable-blue filter. second and third separation layers thus formed constitute The first,

a photoex'posed integral t'ripack'capable of being processed in conventional fashion to formasubtractive trichromatic print.

In alternative forms of the present inventionf-the means for enabling the sequential application'of'opposed com-- pressional forces to the rupturable protective containers of the herein disclosed type are embodied in the pressureapplyingmeansin' conjunction with which the assemblage is employed rather than'in' crush-resistant elementsdi For example;-

r'ectly associated"with the assembla e. obvious mechanical expeaients'e n be utilized to relieve, at appropriate intervals, the opposed compressional forces exerted by the pressure-applying means.

The present invention contemplates a novel process comprising the steps of spreading a photographic composition in a uniformly thin layer between adjacent surfaces of a first sheet and a second sheet, the adjacent surfaces of the first sheet and the second sheet being in contiguous relation, this photographic composition being related in a predetermined manner to the photosensitivity of at least the surface of the first sheet, and maintaining the sheets with their adjacent surfaces in contiguous relation until the photographic composition has performed at least one of its functions.

By such means as assemblage 18 or assemblage 42, it

is feasible to carry out this process when desired with 4 little or no special equipment in order to form a photosensitive layer which is adapted to receive a latent image when photoexposed or in order to intermingle at least two photographic compositions shortly before they are used.

When appropriate, the foregoing steps are combined with the additional steps of photoexposing the first sheet, spreading a processing composition in a uniformly thin layer between adjacent surfaces of the first sheet and another sheet, the adjacent surfaces of the first sheet and the other sheet being in contiguous relation, and maintaining the first sheet and the other sheet with their adjacent surfaces in contiguous relation for a predetermined processing period. The other sheet is either the aforementioned second sheet, for example, sheet 20 in

assemblages

18 and 42, or a third sheet (not shown) the construction of which will now be apparent to those skilled in the art.

The step of photoexposing the first sheet can occur while the first and second sheets remain superposed if one of them is transparent. If both first and second sheets are opaque, they are stripped apart before the step of photoexposing the first sheet occurs.

Further particulars of the process contemplated by the present invention will be apparent from a consideration of the enumerated details of the above-described assemblages.

The term photosensitive and other terms of similar import are herein employed in the generic sense to descri-be' materials possessing physical and chemical prop- "erties whichenable-them-to form usable images when photoexposed by: actinic radiation.

Since certain-'changes may be made-in the above process 5 "withoutdeparting froni the-scope of-the invention herein involved; it is -intiendedthat-"all matter contained in the above" description-or sh'owndntheaccompanying. drawing shall be interpreted as 5 illustrative and 7 not in' a limiting sense.

What-is cl'aimedds: l."A photographic process comprising the steps of si'ipe'rposing a first-sheet on-a second sheet so that asurface'ofsaid first 'sheet and .a surface of said second sheet arein contiguousrelation throughout a predetermined areapat least one of -'said sheets being sufiiciently' trans- --"missive -to actinic radiation to permit-exposure thereth rough, forming a photosensitive coating by spreading a photosensitive composition in-a thinlayerin a substantiallypredeterrnined direction between and in contact -2O' with said contiguous surfaces to form a laminated assemblage, said-photosensitive composition including a material selected fromthe grou consisting of the silver, chrom ate, ferric and diazo'nium photosensitive compounds; thereafter exposing saidphotosensitive coating t-hrough said sheet transmissive to actinic radiation, then spre'ading a processing composition in-a thin layer-inn *s'ubstantially' predetermined direction between said photosensitive coatingandone of said sheets so as to strip "them-apart andthento laminate them together again, '30 *and 'maintaining' said-first and second sheets 'withtheir I 'conti'guous surfaces ins'u'per'posed relation for a predetermined processing time to form a visible image.

-2. 'A."photographic. process comprising the steps of sup'er'p'osing a first sheet on asecond sheet sothat a-surface of said first sheet and a surface of said second sheet are in contiguous relation throughout a predetermined area, at least one of said sheets being sufficiently transmissive to actinic radiation to permit exposure therethrough, spreading a photosensitive silver halide com- 40 position in a thin layer in a substantially predetermined direction between and in contact with said contiguous surfaces to form a laminated assemblage, maintaining said first and second sheets with their contiguous surfaces in superposed relation to permit said photosensitive silver halide composition to become bonded to said first sheet to form a photosensitive coating thereon, thereafter eX- posing said photosensitive coating through said sheet transmissive to actinic radiation, then spreading a process- 1ng composition including a silver halide developer and an alkali in a thin layer in a substantially predetermined direction between said photosensitive coating and said second sheet so as to strip them apart and then to laminate them together again, and maintaining said first and second sheets with their contiguous surfaces in superposed relation for a predetermined processing time to form a visible image.

3. The photographic process according to claim 2 wherein said processing composition also includes a silver halide solvent.

4. A photographic process comprising the steps of superposing a first sheet on a second sheet so that a surface of said first sheet and a surface of said second sheet are in contiguous relation throughout a predetermined area, said surface of said first sheet having a coating thereon of a photosensitive silver halide composition,

at least one of said sheets being sufiiciently transmissive to actinic radiation to permit exposure therethrough, spreading a photosensitizing composition selected'from the group consisting of the silver halide optical sensitizers and silver halide hypersensitizers in a thin layer in a substantially predetermined direction between and in contact with said contiguous surfaces to form a laminated assemblage, maintaining said first and second sheets with their contiguous surfaces in superposed relation to permit said photosensitizing composition to predeterminedly modify.

the photosensitivity of said coating, thereafter exposing said coating through said sheet transmissive to actinic radiation, then spreading a processing composition 1neluding a silver halide developer and an alkali in a thin layer in a substantially predetermined direction between said coating and said second sheet so as to strip them apart and. then to laminate them together again, and maintaining said first and second sheets with their contiguous surfaces in superposed relation for a predetermined processing time to form a visible image.

5. A photographic process comprising the steps of superposing a first sheet on a second sheet so that a surface of said first sheet and a surface of said second sheet are in contiguous relation throughout a predetermined area, said surface of said first sheet having a coating thereon of a hydrophilic colloid material, at

least one of said sheets being suificiently transmissive to actinic radiation to permit exposure therethrough, spreadsive to actinic radiation, then spreading a processing composition in a thin layer in a substantially predetermined direction between said coating and said second sheet so I as to strip them apart and then to laminate them together again, and maintaining said first and second sheets with their contiguous surfaces in superposed relation for a predetermined processing time to form a visible image. 6. A photographic process comprising the steps of super-posing a first sheet on a second sheet so that a surface of said first sheet and a surface of said second sheet are in contiguous relation throughout a predetermined area, at least one of said sheets being sufiiciently transmissive to actinic radiation to permit exposure there through, forming a photosensitive coating by spreading a photosensitive composition in a thin layer in a substantially predetermined direction between and in contact With said contiguous surfaces to form a laminated assemblage, said photosensitive composition including a material selected from the group consisting of the silver, chromate, ferric and diazonium photosensitive compounds, then spreading a processing composition in a thin layer in a substantially predetermined direction between said photosensitive coating and one of said sheets so as to strip them apart and then to laminate them together again, immediately after spreading said processing composition exposing said photosensitive coating through said sheet transmissive to actinic radiation, and maintaining said first and second sheets with their contiguous surfaces in superposed relation for a predetermined processing time to form a visible image.

References Cited in the file of this patent UNITED STATES PATENTS 7,458 Whipple et a1. June 25, 1850 1,582,050 Johnson Apr. 27, 1926 2,520,641 Land Aug' 29, 1950 2,565,376 Land Aug. 21, 1951 2,584,029 Land Jan. 29, 1952 FOREIGN PATENTS 814,449 France Mar. 15, 1937

Claims

2. A PHOTOGRAPHIC PROCESS COMPRISING THE STEPS OF SUPERPOSING A FIRST SHEET ON A SECOND SHEET SO THAT A SURFACE OF SAID FIRST SHEET AND A SURFACE OF SAID SECOND SHEET ARE, IN CONTIGUOUS RELATION THROUGHOUT A PREDETERMINED ARE, AT LEAST ONE SAID SHEETS BEING SUFFICIENTLY TRANSMISSIVE TO ACTINIC RADITION TO PERMIT EXPOSURE THERETHROUGH, SPREADING A PHOTOSENSITIVE SILVER HALIDE COMPOSITION IN A THIN LAYER IN A SUBSTANTIALLY PREDETERMINED DIRECTION BETWEEN AND IN CONTACT WITH SAID CONTIGUOUS SURFACE TO FORM A LAMINATED ASSEMBLAGE, MAINTAINING SAID FIRST AND SECOND SHEETS WITH THEIR CONTIGUOUS SURFACES IN SUPERPOSED RELATION TO PERMIT SAID PHOTOSENSITVE SILVER HALIDE COMPOSITION TO BECOME BONDED TO SAID FIRST SHEET TO FORM A PHOTOSENSITIVE COATING THEREON, THEREAFTER EXPOSING SAID PHOTOSENSITIVE COATING THROUGH SAID SHEET TRANSMISSIVE TO ACTINIC RADITION, THEN SPREADING A PROCESSING COMPOSITION INCLUDING A SILVER HALIDE DEVELOPER AND AN ALKALI IN A THIN LAYER IN A SUBSTANTIALLY PREDETERMINED DIRECTION BETWEEN SAID PHOTOSENSITIVE COATING AND SAID SECOND SHEET SO AS TO STRIP THEM APART AND THEN TO LAMINATE THEM TOGETHER AGAIN, AND MAINTAINING SAID FIRST AND SECOND SHEETS WITH THEIR CONTIGUOUS SURFACER IN SUPERPOSED RELATION FOR A PREDETERMINED PROCESSING TIME TO FORM. A VISIBLE IMAGE.
3. THE PHOTOGRAPHIC PROCESS ACCORDING TO CLAIM 2 WHEREIN SAID PROCESSING COMPOSITIONALSO INCLUDES A SILVER HALIDE SOLVENT.