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Publication numberUS2968554 A
Publication typeGrant
Publication dateJan 17, 1961
Filing dateAug 9, 1954
Priority dateAug 9, 1954
Publication numberUS 2968554 A, US 2968554A, US-A-2968554, US2968554 A, US2968554A
InventorsLand Edwin H
Original AssigneePolaroid Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Photographic transfer processes for forming multicolor dye images and photographic products for carrying out the same
US 2968554 A
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Description  (OCR text may contain errors)

w D WW Jan. 17, 1961 E. H. LAND 2,968,554

PHOTOGRAPHIC TRANSFER PROCESSES FOR FORMING MULTICOLOR DYE IMAGES AND PHOTOGRAPHIC PRODUCTS FOR CARRYING OUT THE SAME Filed Aug. 9, 1954 2 Sheets-Sheet 1 Red-Sensilive Emulsion, Coupler for Cyan, Filler Dye and Colon-Forming Developing Agenl Green Sensilive Emulsion, Coupler for Mogen'lo, Filler Dye and CoIor'Formin Developing Agenl Red-Sensifive Emulsion, Coupler for Cyan, Filler Dye and Color-Forming Developing Agent Blue -Sensil'ive Emulsion, 27 Coupler for Yellow, and Color-Forming Developing Agenr Green-Sensi'live Emulsion, Coupler for Mqgenl'a, Filler Dye and a Color-Forming Developing Agenl' INVE OR ATTORNEYS Jan. 17, 1961 N15 554 E. H. 2 96 PHOTOGRAPHIC TRANSFER PROCESSES FOR FORMING MULTICOLClR 13%;:

IMAGES AND PHOTOGRAPHIU PRODUCTS F Filed Aug 9' 1954 V I OR CARRYING OUT THE SAME Green-Sensifivc Emulsion and Coupler 35 V 34 35 {lnsulofinq Layer l Con'lqining Developing Agcnl 32 Red-Sensilive Emulsion 3| 0'] m {Layer Conlainlng Developing 3 4 Agcnl' and Coupler Imago Receiving Layer Piclurc Area {Green Sonsifive Emulsion Conluining Color Forming Componcnls O suppo rl 2{Rd-Scnsllivc Emulsion Conlaining V Color-Forming Componcnls FIG. 5 I BY ATTORNEYS 2 Sheets-Sheet 2 PHOTOGRAPHIC TRANSFER PROCESSES FOR FORMING MULTICOLOR DYE IMAGES AND PHOTOGRAPHIC PRODUCTS FOR CARRYING OUT THE SAME Edwin H. Land, Cambridge, Mass, assignor to Polaroid Corporation, Cambridge, Mass., a corporation of Delaware Filed Aug. 9, 1954, Sex. No. 448,441

32 Claims. (Cl. 96-3) This invention relates to color photography and more particularly has reference to a one-step photographic process for forming multicolor images and to film units for carrying out said process, as well as to photosensitive elements useful with said film units.

This application is in part a continuation of my copending application Serial No. 176,961, filed August 1, 1950, for Multicolor One-Step Photographic Process and Photographic Product for Carrying Out the Same (now abandoned).

Up to the present, color photography has closely followed the concepts made known by such workers as Maxwell, Du Hauron and Cross, beginning with the 1860s. Since that time, significant advances in the art have been restricted to the provision of mechanical and chemical means for carrying these concepts into effect, as for example the provision of the modern monopack and the use of dye coupling procedures.

With the advent of the silver halide transfer process, a broad new field of color photography has been opened in the adaptation of the transfer process to color work so that multicolor image formation may be carried out by automatic processing and in one step.

While the transfer process described herein recognizes the trichromatic mechanism of color vision, in that it relies upon the use of individual color records to provide multicolor images, the process of this application makes material departure, in a number of respects, from conventional color photographic practices.

All conventional photographic color processes depend upon two series of procedural operations. By one series of operations, a colored scene is recorded negatively. In the case of a subtractive color system, this recordation will be carried out to provide a plurality of negative color component images. A single negative image is, however, employed in the case of an additive color screen system and, in conjunction with the screen, provides the necessary components to make up a multicolor negative record.

By the second conventional series of operations, a positive record is formed from the negative to obtain a portrayal of the color scene as viewed by the eye. The positive record may be formed by reversal of the negative and removal of the material which forms the visible negative record, or by printing the negative record on a previously unexposed photosensitive element and processing the latter. As in the case of the negative record, the positive record in a subtractive color synthesis will comprise a plurality of positive color component images. Similarly, the positive record in an additive color screen process will comprise a single positive image which, in conjunction with a color screen, provides the components needed to produce a multicolor image.

Conventional subtractive systems in color photography, carried out by color-forming development of a photosensitive element having coupler materials contained therein, without exception incorporate couplers in the photosensitive element so that particles of coupler for sin-xii are each subtractive color to be reproduced are separated from particles of coupler for each other color to be reproduced, and depend upon maintaining these particles in immobile condition throughout color processing in order to carry out successful multicolor reproduction. As a result, the dye particles formed from coupler particles, converted to dye on color development, are also separated from each other but are located in the photosensitive element in the positions of the coupler particles they replace. The multicolor reproduction is obtained by the optical combination or intermingling of the physically separated, developed dye particles.

Similarly, in conventional additive processes, as exemplified by color screen systems, the dyed screen elements must be maintained in immobile condition and are located so as to be spread out over and mounted upon the surface of a transparent support in side-by-side relation and in such manner that while they cover the support and contact each other, they do not overlap. Thus, each color element of the screen is a distinct entity which is separated from each other color element and the multicolor reproduction is obtained by optical intermingling of thecolors in the screen as controlled by the silver image associated therewith.

In achieving the concept of multicolor reproduction in one step the present invention departs and. differs from well established, conventional principles and, in fact, in at least certain aspects attains its end by practices which are directly contrary to the teachings of the prior art. For example, among these difierences and departures, the present invention 1) Exposes a taking photosensitive element through an additive screen structure but views a positive print produced from said negative without the screen;

(2) Associates, in a screen pattern made up of silver halide elemental portions which are selectively exposable by light of primary colors corresponding to colors of an additive synthesis, reagents which provide subtractive dyes;

(3) Transports particles of reagents, which provide dyes of desired colors, from one layer to another layer and, in fact, transports different reagents in individual solutions from a negative photosensitive element to a positive imageor print-receiving element and there provides a multicolor positive print with the transported reagents;

(4) Forms subtractive dye mixtures in an image receiving layer with the assistance of reagents transported thereto from a photosensitive element wherein said reagents are maintained in individual portions of the element which are distinct and separate from each other;

(5) Preferably utilizes controlled sidewise diffusion of a liquid when imbibed by an image-receiving layer from a negative element in superposed reiation thereto whereby to deposit on the image-receiving layer, in overlapping relation, different reagents and provide dye mixtures on the image-receiving layer with said reagents;

(6) Uses a negative photosensitive element having selectively exposable portions arranged in a screen pattern thereon whereby the negative element is itself the screen and the screen and the negativematerial are an entity; and

(7) Employs different reagents which are individually incorporated in different silver halide photosensitive portions and which are dispersible in liquid, permeated into each said portion and used as a means for effecting the development of latent image silver halide present therein, but which becomes substantially immobilized in each said photosensitive portion as a function of the development of latent image silver halide and associates these reagents in the photosensitive portions of a photosensitive element having a plurality of sets of selectively exposable photoassssst sensitive portions mounted in a pattern to simulate a photographic color screen and arranged with their exposure faces in side-by-side relation, to the end that at least a part of each reagent remaining mobile in a photosensitive portion af ter silver development of the element is diifusible in liquid through the face of said portion for deposit upon an image-receiving layer located in superposed relation to the photosensitive element and is used where deposited to color the image-receiving layer a predetermined color.

Objects of the invention are to provide a process for forming a multicolor image by transfer techniques wherein different reagents, representative of the colors used in subtractive color photography, are transferred to an image-receiving element from unexposed parts of a photosensitive element having a multiplicity of light-sensitive elemental portions having silver halide therein, said elemental portions being selectively exposable by light of wavelength representative of the colors used in additive color photography and being substantially uniformly dis tributed upon a support in an arrangement simulating the pattern for a photographic color screen whereby the elemental portions are individually exposable, and wherein each different reagent so transferred and deposited upon the image-receiving element colors the image-receiving element a predetermined color to provide thereon a multicolor image comprising positive dye component images of negative latent color component images formed by the exposure of said photosensitive element; and to provide a multicolor transfer process specifically designed for carrying out two-color and three-color photography.

Another object of the invention is to provide a multicolor transfer process of the character set forth wherein imagewise distributions of different reagents, comprising reagents for imparting predeterminedly different colors to image-receptive material, are formed in unexposed parts of a negative photosensitive element of a character having a multiplicity of light-sensitive elemental portions which comprise silver halide and at least one of said reagents and which are constituted by at least two sets of elemental portions of a nature such that the elemental portions of one set of said portions are selectively exposable by light of a wavelength diiferent from that employedto expose the elemental portions of another set of said portions and which aredistributed on a support in an arrangement providing a color screen type of pattern, and wherein said imagewise distributions of said reagents are transferred in solution and by imbibition to image-receptive material which is so arranged in superposed relation to the negative photosensitive element that the reagent in each imagewise distribution is spread or diffused sidewise on the imagereceptive material whereby reagents, transported from adjacent elemental portions, will overlap on the imagereceptive material.

Still another object of the invention is to provide processes for forming color images by transfer of at least two different reagents of which each reagent is contained in the photosensitive portions of a predetermined one of at least two sets of selectively exposable photosensitive silver halide portions comprising a photosensitive element and arranged in side-by-side relation in a pattern simulating a photographic color screen by the steps of exposing the photosensitive element to a colored object, permeating a processing liquid into each said photosensitive portion and causing to be formed in the permeated liquid a dispersion of the reagent contained in said portion, developing by means of the liquid, the latent image silver halide of said portions, causing said development to immobilize the dispersed reagent in each said photosensitive portion as a function of said development, diffusing liquid in each photosensitive portion through the exposure face thereof totransport at least a part of the reagent remaining mobile in said portion after said development to an image-receiving layer located in superposed relation to the photosensitive element, and depositing the transferred reagents on areas of the image-receiving layer opposite said photosensitive portions, each different reagent so deposited upon the image-receiving layer coloring said layer a predetermined color.

Further objects of the invention are the provision of a photosensitive element, usable in a multicolor process, which comprises a support and a multiplicity of light-sensitive elemental portions mounted thereon and made up of at least two sets of elemental portions of different character such that the elemental portions in each set comprise silver halide and possess a light sensitivity or are restricted to a light sensitivity different in wavelength from that of light by which the elemental portions of each other set are adapted to be exposed and wherein said elemental portions control color formation and are mounted in a contiguous arrangement so that the individual portions of said sets have their respective exposure faces in side-byside relation in a pattern similar to that possessed by a photographic color screen and form a surface through which said photosensitive element is exposable; to provide a photosensitive element of the just-described nature wherein each light-sensitive elemental portion comprises silver halide and at least a predetermined reagent adapted, at least in part, to be removed from said photosensitive element and transferred to a print-receiving layer for coloring the print-receiving layer; to provide a photosensitive element making use of at least two sets of lightsensitive elemental portions of the character set forth wherein the reagent controlled by each light-sensitve elemental. portion is of a character effective for coloring a print-receiving layer a color which is complementary to the color of the light employed to expose said elemental portion; and especially to provide a photosensitive element, usable in carrying out a multicolor process of a nature employing reagents such as a photographic coupler material or a dye which is capable of coupling with an oxidized silver halide developer or a dye which is itself a silver halide developer.

A still further object of the invention resides in the provision of a photographic product in the'nature of a film unit especially adapted for use in a transfer process and comprising a photosensitive element or negative'material having a multiplicity of light-sensitive elemental portions thereon of the character described, a positive image-receiving element adapted to beassociated with said negative photosensitive element in superposed relation thereto, and a container holding a liquid processing composition for processing said film unit after exposure thereof.

Other objectsiof'the invention Will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the product possessing the features, properties and the relation ofcom ponents and the processes involving the several steps and the relation and order of one or more of such steps with respect to each of the others, which are exemplified'in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

Figure 1 is a diagrammatic perspective view of one embodiment of a negative photosensitive element for use in carrying out this invention;

Fig. 2 is a diagrammatic perspective view of another embodiment of a negative photosensitive element;

Fig. 3 is a diagrammatic plan view of still another embodiment of a negative photosensitive element for use in carrying out this invention;

Fig. 4 is a side elevation of the photosensitive element of Fig. 3; and

Fig. 5 is a diagrammatic cross-sectional view of a film unit whichisillustratedas beingdnthe course of process-- ing and which specifically comprises a negative photosensitive element of the character illustrated in Fig. l in combination with a positive image-receiving element suitable for use with any photosensitive element with which the invention may be practiced.

Techniques for carrying out a transfer process in color are disclosed in Patent No. 2,559,643, issued to Edwln H. Land on July 10, 1951, for Photographic Product and Process, Patent No. 2,661,293, issued to Edwin E. Land on December 1, 1953, for Process of Producing a Colored Photographic Image by Means of Exhaustions of Developer, and application Serial No. 94,647, filed by Edwin H. Land on May 21, 1949, for Color Photographic Process and Product. By these techniques, a negative latent image in a silver halide emulsion of a photosensitive element is processed to provide a dye positive image thereof in or on another layer comprising an image'receiving element. In this treatment, a liquid processing composition is permeated into both the negative and the positive elements as, for example, by immersing the negative photosensitive element in the composition and then bringing it into contact with the positive image-receiving element or by spreading the liquid composition in contact with and between both said elements. A color-forming developing agent and a coupler material are adapted to be dissolved in the processing composition at an appropriate stage of processing whereby both the developing agent and coupler material are present in the silver halide emulsion to effect the development thereof.

As a result of development, there is formed in the photosensitive element a negative silver image and a dye image in situ therewith and also an imagewise distribution of unreacted developing agent and unreacted coupler material which is transferred in solution and by imbibition to the positive image-receiving element. Unreacted developer, which is transferred to the positive image-receiving element and is there oxidized, enters into a coupling reaction with coupler material also transferred to the positive image-receiving element whereby to provide a positive dye image of the latent image in the negative photosensitive element.

The just-mentioned patents and application disclose a negative photosensitive element comprising a support, a silver halide emulsion layer and at least one other layer, and may have a color-forming developing agent and a coupler incorporated in some layer of the negative photosensitive element. Also, the just-mentioned patents and application show an image-receiving or positive material comprising an image-receiving layer which is coated with a permeable material containing an oxidizing agent.

Good quality monochromatic transfer image have been obtained in accordance with the teachings of the previously mentioned patents and application. Also, multicolor images have been successfully obtained by superposing monochromatic positive transparencies which represent appropriate color component images.

The present invention is concerned with improved procedures for obtaining multicolor images whereby two or more positive dye component images are formed substantially simultaneously on an image-receiving element by a one-step photographic process involving the transfer of an individual reagent for each dye component image from a negative photosensitive element to a positive imageor print-receiving element.

The transfer process involved in this invention makes use of a negative photosensitive element which comprises a support having a multiplicity of light-sensitive elemental portions or photosensitive portions, comprising silver halide, mounted thereon and made up of at least two sets of elemental portions which are of different character and which are adapted to control color formation. The elemental portions in each set possess a light sensitivity or are restricted to a light sensitivity different from the wavelength of light by which the elemental portions of each other set are adapted to be exposed. In addition, these elemental portions are preferably substantially uniformly distributed over the support and are mounted thereon in a contiguous arrangement so that the individual portions of said sets have their respective exposure faces in side-by-side relation in a pattern similar to that possessed by a photographic color screen and form a surface through which the photosensitive element is expo sable. Thus, the outer surface of each elemental or photosensitive portion is uncovered by any part of any other elemental portion, although a part at least of each elemental portion may contact one or more other elemental portions in a direction perpendicular to said outer surface. In this manner the elemental portions: are made individually exposable through their outer and uncovered surfaces. It is also to be noted that each elemental portion is characterized by the fact that it has at least one dimension which is relatively minute.

A dilferent reagent of a nature suitable for imparting a desired color to a positive print-receiving element or image-receiving layer is associated or incorporated within each photosensitive elemental portion of each set of elemental portions of the negative photosensitive element. In addition to the requirement for imparting a desired color, each reagent must be dispersible in a liquid processing composition permeated into the photosensitive element and must become immobilized in the elemental portion in which it is associated as a function of the development of latent silver halide therein. At least part of each reagent remaining dispersed after silver development in liquid permeated into an elemental portion is intended to be diffused through the exposure face of the elemental portion onto an image-receiving layer in superposed relation to the photosensitive element.

Reagents which meet these requirements and which are useful for carrying out the invention comprise (1) con ventional photographic coupler materials which are reactable with conventional color-forming silver halide developers in oxidized condition to provide dyes of appropriate colors, (1a) certain photographic couplers such as phenolic and naphtholic coupler compounds or couplers having a reactive methylene group, which are reactable with the oxidation product of color-forming silver halide developers and which are also reactable, in an alkaline environment, with stabilized and diazotized salts to provide colored compounds or dyes, (2) dyes of suitable colors and of a nature having a coupling group or function and which are able to couple with conventional colorforming silver halide developers in oxidized condition, and (3) suitably colored compounds which are themselves dyes and which possess a silver halide developing function, i.e., dye developers.

Each elemental portion of the photosensitive element may comprise a mixture of materials formed by incorporating a reagent of the character described in a silver halide emulsion to which an appropriate silver halide developer may be added. Alternatively, each elemental portion may be built up in two or more layers or strata which are individually adapted to contain silver halide, a reagent of the character described, a silver halide developer Where necessary, or some combination of these justmentioned materials.

A result of development of exposed parts of elemental portions in the negative material is to provide in said negative material an imagewise distribution of reagents in unexposed or less than completely exposed parts of each set of elemental portions. These imagewise distributions of reagents are, at least in part, transferred in solution and by imbibition to image-receptive material which is arranged in superposed relation to the negative photosensitive element at such spacing therefrom that the unreacted reagents in each imagewise distribution will spread or dif-, fuse sidewise or laterally in or on the positive element whereby unreacted reagents transported from adjacent element portions will overlap and form mixtures on the image-receptive material to the end of providing the desired colors therein.

In view of the foregoing, it will be appreciated that this invention broadly comprehends the use of reagents which are predeterminedly deposited upon an image-receiving layer for coloring said layer. In this regard, the inventive concept is satisfied when carried out by the use of one of the following mechanisms: (a) by the employment of reagents which are transfered to the imagereceiving layer in unreacted condition but which must undergo reaction in order to provide the desired color in the image-receiving layer, or (b) by the employment of reagents which are transferred to the image-receiving layer in unreacted condition and which are usable in unreacted condition for coloring the image-receiving layer, or (c) by the employment of reagents which are transfered to the image-receiving layer is reacted condition and which are used in reacted condition for coloring the image-receiving layer.

Photographic couplers are examples of reagents which satisfy the just-mentioned mechanisms (a) and (c) in that they maybe either transferred to the image-receiving layer in unreacted condition and there reacted to color the layer or in that they may be transferred to the imagereceiving layer in reacted condition and used in reacted condition to color said layer.

Dyes which are able to couple with oxidized silver halide developers and also dyes which possess a silver halide developing function are examples of reagents which satisfy the previously mentioned mechanism (b) above in that they provide reagents which are usable in unreacted condition for coloring the image-receiving layer. Reagents of mechanism (b) are in general preferred inasmuch as they make it possible to avoid the need for a reaction in the print-receiving element and also avoid carrying out two reactions in the negative element as in the case of couplers which are adapted to be reacted with oxidized color developer and also with a stabilized and diazotized salt.

The basic aspects of the present invention will be well understood by reference to its practice with photographic couplers as reagents for carrying out color image formation and their use in accordance with the previously mentioned mechanism (a) wherein unreacted coupler material is transferred to the image-receiving layer and there is reacted with the oxidation product of a color developer which has been transferred or which is present in the image-receiving layer in unoxidized condition. Additionally, explanation of the invention in connection with this use of photographic couplers will admirably serve to detail the general processing steps and the structure of the products required to carry the invention into effect regardless of the type of reagents employed. Accordingly, the practice of the invention will be detailed at some length exclusively in connection with the use of photographic couplers and their transfer to the image-receiving layer in unreacted condition, following which the practice of the invention by the employment of other mechanisms and other types of reagents will be presented.

A negative photographic element it), useful in carrying out the invention for obtaining a two-color positive print, is disclosed in Fig. l as comprising a support 11 over'the surface of which is cast a composition comprising a red-sensitive silver halide emulsion 12 of relatively high silver content. A color-forming developing agent and a coupler, which is capable of coupling with oxidized developing agent to form a cyan dye, are substantially uniformly distributed throughout the red-sensitive emulsion 12, and this composition is cast upon the support it to entirely cover a surface thereof.

A second composition comprising a green-sensitive silver halide emulsion of relatively high silver content is employed in this embodiment of the invention and also has a coupler and a color-forming developing agent incorporated therein. The developing agent distributed in the green sensitive' emulsion may be the same developing agent as that employed with the red-sensitive emulsion 12.

A coupler which is capable of reacting with oxidized developing agent to provide a dye of a magenta color is employed with the green-sensitive emulsion. It is to be observed that the couplers employed with the redand green-sensitive emulsions each form dyes of a color respectively complementary to the red and green regions of the spectrum over which the emulsions are respectively sensitive.

In the embodiment illustrated in Fig. l, the greensensitive emulsion is laid down upon the surface of the emulsion 12. in the form of line elements 14 which are parallel to each other and extend from end to end or side to side of the emulsionlayer 12. The result of this expedient is to cover portions of the layer 12 by overlaid line elements 14 of green-sensitive emulsion and to leave portions of the layer 12 uncovered between the line elements 14 provided by the green-sensitive emulsion whereby 'to create asecond set of line elements 15. Thus, the surface of the negative photosensitive element 10 will comprise a series of line elements 14 and 15, alternate ones of which are red-snsitive and green-sensitive. Such a practice obviously provides a screen structure of the color screen type. In this regard the processes herein set forth may be termed additive-subtractive screen processes. In accordance with the nature of a color screen, the line elements formed by the red-sensitive and green-sensitive emulsions are extremely'narrow and, for the purpose of illustration, their width has been greatly exaggerated throughout the drawing. In actual practice there will be about 250 lines per inch.

From a generic standpoint, the term elemental portions is comprehensive of the just-described line elements 14 and 15, as well as of other geometrical shapes which are characterized by having at least one relatively minute dimension and by being positionable in side-by-side relation in a screen pattern to have outer surfaces which provide exposure faces and which may each have the appearance of a dot or a square or the like.

In the two-color negative element of Fig. 1, it is preferable to employ a yellow filter dye or a blue absorber in conjunction with each emulsion whereby to filter actinic light in'the blue region of the spectrum. For this purpose a dye or other absorbing material may be placed in or on each emulsion carried on the support 11. Auramine or colloidal silver are examples of materials which provide suitable blue-absorbing filters. Colloidal silver may be incorporated in gelatin and auramine may be incorpora in cellulose acetate hydrogen phthalate to provide suitable coating materials, either one of which may be coated over the outer surface of the photosensitive element 10 after the formation of the line elements or elemental portions 14 and 15. Auramine and colloidal silver are both particularly adapted for use as light filter materials. Auramine, while soluble in developing agent, is bleached by alkali in the developer solution so that undesired dye stain in the positive transfer image is avoided. On the other hand, colloidal silver will not transfer from the negative material to the image-receiving layer of the positive material.

In regard to the use of filter media, it is pointed out that the structures set forth herein are of a nature which makes it possible to associate filter media with a lightsensitive portion which will modify the exposure of the light for that light-sensitive portion only but will have substantially no effect on the exposure light for lightsensitive elemental portions with which that particular filter media is unassociated.

A more accurate color'recording may be obtained by the use of emulsion sensitivities and a combination of couplers dilferent from that disclosed in conjunction with the embodiment of the invention set forth in Fig. 1. For example, it is desirable to limit the sensitivity of one emulsion to one-half of the visible spectrum, and to limit the sensitivity of: the" other emulsion to the other half of the visible spectrum and to employ couplers which are complementary over each of these ranges. In this regard, a coupler which is capable of reacting with oxidized developing agent to give a red dye is employed with a blue-green-sensitive emulsion such as that referred to in Fig. 1. With coupler material capable of forming a red dye, a filter for blue light is omitted from use in conjunction with the blue-green-sensitive emulsion. A red-sensitive emulsion like that described, having a coupler for cyan incorporated therein, may be used for the second sensitive component which is adapted to have a blue absorber associated therewith. These and other variations, as will he understood to the art, are within the scope of this invention. Coupler material capable of forming a red dye, when reacted with oxidized developing agent, is readily obtainable. For example, as will be well understood, such material may comprise an appropriate mixture of a coupler which will couple to give magenta and a coupler which will couple to give yellow such as a mixture of p-nitrophenylacetonitrile and acetoacet-Z-chloranilide.

The sensitive components, such as the line elements is and 15', may be laid down or deposited upon a support by mechanical expedients. For example, the green-sensitive composition of the embodiment illustrated in Fig. 1 may be symmetrically deposited upon layer 12 to provide line elements 14 as by printing the green-sensitive composition onto the layer 12 to leave uncovered emulsion portions in the form of red-sensitive line elements 15. For that matter, both the red-sensitive and the greensenstitive compositions may be applied to the support of Fig. 1 by printing in proper relation wtih each other. Ruling practices may also be employed for providing line elements on a support. 1

Suitable compositions may be preformed into shape appropriate for screen elements and then assembled into a screen pattern. For example, compositions such as those described which comprise photographic materials incorporated in gelatin, as well as compositions which comprise photographic materials incorporated in suitable organic plastics of a nature such that they are permeable but inert to liquid processing composition, may be extruded or drawn in the form of filaments and individual filaments thus formed may be laid down or assembled in a pattern upon a suitable support surface. It is also within the scope of this invention to utilize filament forming compositions from which silver halide is omitted whereby such compositions will be nonphotosensitive.

While preformed filaments may be deposited in overlying relation to each other to provide a screen pattern similar to that shown for the negative photosensitive element 1!), for practical reasons it will be preferable to place the preformed filaments upon a support in side-byside relation and substantially without overlying each other whereby to provide a screen pattern which may be in the form of parallel lines.

The red-sensitive component for providing the emulsion layer 12 of the negative element 10 of Fig. 1 is formed by first preparing a mixture of a color-forming developing agent, triphenyl phosphate and sodium hydroxide in the following proportions:

Z-amino 5 diethylaminotoluene monohydrochlo ride grams 2.14 Triphenyl phosphate do 40 Sodium hydroxide (5% aqueous solution) cc 8 The above mixture is warmed to 50 C. to melt the triphenyl phosphate. When the triphenyl phosphate is melted, the mixture is shaken and, as the free base of the color developer is formed, it is dissolved in the triphenyl phosphate. Following this, a coupler material is added to the mixture, specifically 1.6 grams of 2,4-dichloro-l-naphthol. 8.8 grams of the above mixture with the coupler added thereto is then emulsified into 40 cc. of water which contains 1% of gelatin and to which a small amount of emulsifying agent, as for example alkyl lauryl sulfate, has been added. 24.4 grams of the emulsified product is then added to 200 grams of a red-sensitive silver halide emulsion and is thoroughly mixed therewith.

A green-sensitive component, for providing the line elements 15 in the embodiment of the invention disclosed in Fig. l, is prepared from a mixture of a developing agent, triphenyl phosphate and sodium hydroxide in the proportions noted above in connection with the preparation of a red-sensitive emulsion. How-- ever, the starting mixture employed for the formation of the green sensitive emulsion has a different coupler material added thereto after the triphenyl phosphate has been melted. In the formation of the green-sensitive emulsion, 1.07 grams of p-nitrophenylacetonitrile is added and 3.5 grams of the resultant composition is emulsified directly into cc. of a green-sensitive silver halide emulsion.

The triphenyl phosphate, disclosed in conjunction with the mixtures of developing agent and coupler, is a high boiling point solvent and is a material which has been found beneficial for introducing and maintaining coupler materials within emulsion layers. It is also recognized by the art that high boiling point solvents of the character of triphenyl phosphate exert a material restraint upon desensitization of the emulsion layer by .a developing agent included therein.

As previously pointed out, the emulsion providing the red-sensitive components is cast over the entire surface of the support 11 and the emulsion providing the greensensitive component is laid down upon the red-sensitive emulsion in the form of line elements 14.

The blue-absorbing material is coated upon the emulsion face of the element 10 after both emulsions have been mounted upon the support.

It may be here remarked that the support 11 of the negative element 19 may comprise any conventional film base material and may be transparent or opaque. Usually, an opaque material will be employed and may be provided by any suitable paper. In general, paper of the type known as baryta is a preferred material for this purpose.

The embodiment of the invention illustrated in Fig. 1 has shown a negative element for carrying out a twocolor process. Fig. 2 illustrates an element 20 similar to that disclosed in Fig. 1 but suitable for carrying out a three-color process. The element of Fig. 2 comprises a support 21 of a material like that of the support of Fig. 1. A layer 22 of a red-sensitive silver halide emulsion, like that previously described, is cast over an entire face of the support 21. Upon the emulsion 22 a greensensitive silver halide emulsion, also like that heretofore described, is laid down in the form of line elements 24, which are in spaced relation and are substantially parallel to each other. The negative element so far described will have an appearance substantially like that of the element 16 of Fig. l. A third composition, comprising a blue-sensitive silver halide emulsion of a relatively high silver content, is laid down across the emulsion layer 22 and the line elements 24 of green-sensitive emulsion to provide line elements 27 of blue-sensitive emulsion, which are shown as substantially at right angles to the line elements 24 of green-sensitive emulsion. Like the lineelements 24, the line elements 27 are spaced apart in substantially parallel relation to each other. After laying down the line elements 24 and 27, only substantially square portions 25 of red-sensitive emulsion are present in an uncovered condition. Similarly, only substantially square portions 26 of green sensitive emulsion remain uncovered. To obtain good color balance, the width of the line elements 24 and 27 are selected so that, in general, the total area of the uncovered portions of each emulsion will be similar.

Appropriate couplers for use with the blue-sensitive emulsion are acetoacet-Z-chloranilide or acetoacet-2,5-dil1 chloranilide. A suitable developing agent for use with the blue-sensitive emulsion is 2-amino-5-diethylarninotoluene. The developing agent and coupler, in appropriate quantities, are mixed with triphenyl phosphate by procedures similar to those heretofore outlined, and this mixture is added to an appropriate quantity of blue-sensitive emulsion, likewise in a manner similar to that heretofore set forth. In three-color work, a blue absorber, such as auramine or colloidal silver, is employed in or over the redand green-sensitive components, but is not required for the blue-sensitive component.

For the purpose of carrying out any transfer process, a liquid processing composition is permeated into the negative material employed and also into positive material which is used in conjunction with the negative material and which is in contact therewith. The processing composition employed With a negative element having elemental portions which each include a developing agent, a coupler and a photosensitive emulsion comprises a liquid solvent for both developing agent and coupler. In the case of a negative material having overlying emulsions, as are illustrated in connection with the sensitive compositions of negative elements 16 and 20 of Figs. 1 and 2, the processing composition is adapted to penetrate into uncovered or sensitive elemental portions of the screen pattern and to transfer unreacted developing agent and unreacted coupler from regions of said uncovered portions wherein no exposure of silver halide has occurred.

It will be obviously undesirable for coupler and developing agent contained in sensitive material which lies under an elemental screen portion and which possesses diiferent color-forming properties from the color-forming components incorporated in the overlying elemental portion to be transported to an image-receiving layer by processing composition penetrated into the negative element. For example, in connection with the negative element of Fig. l, coupler material from the red-sensitive emulsion which lies under a line element 14 should not be transported through the green-sensitive emulsion of said element 14 and onto the image-receiving layer employed for formation of the positive image. Such a condition could result in producing cyan dye stain in areas of the multicolor positive print which should only be magneta in color.

In the case of overlying emulsions, a convenient penetration control may be provided by the use of insulating layers which are located between superposed emulsions but not over portions of an emulsion which remain uncovered by any other emulsion. insulating material should be at least diflicultly penetrable and substantially inert to liquid processing composition including developing agent and alkali dissolved therein. Examples thereof include cellulose nitrate, partially hydrolyzed polyvinyl acetate, and the like. Variation in the thickness of the layer of insulating material may be utilized in conjunction with the lack of permeability of the layer to control penetration of the liquid processing composition through the material. In the case of insulating layers formed of cellulose nitrate, succesful results have been obtained with layers having a thickness of the order of about 0.0601 inch or less. It is also desirable, for reasons which will presently appear, that the insulating material employed should be capable of easy removal. Materials mentioned possess this property and may be removed with suitable solvents such as butyl acetate, ethyl acetate, methanol or the like;

The manner of application of the insulating layers will lead to a fuller understanding of their structure as well as their use and such may be illustrated with particular reference to the negative element of Fig. 2. In Fig. 2, after the red-sensitive emulsion 22 has been cast upon the support 21, the outer surface of the emulsion may be coated with a coating of cellulose nitrate in ethyl acetate. Two applications of 6% cellulose nitrate one-half second viscosity in ethyl acetate have proved satisfactory for this purpose. This mixture may be applied in any conventional manner, as for example by dipping, flowing, rollcoating, or the like. The insulating coating just described may be placed upon the red-sensitive emulsion 22 either before or after a blue-absorbing filter material has been placed thereon. Following this, the screen lines 24 of green-sensitive emulsion are laid down and these, in turn, are coated in a similar manner with the previously mentioned insulating composition, after which the screen lines 27 of blue-sensitive emulsion are laid down over the red-sensitive and green-sensitive emulsions. The insulating coating placed upon the photosensitive element 20, after application of the emulsion providing the screen lines 24, may be applied either before or after a blueabsorbing filter material has been placed on these screen lines.

As a result of this practice, it will be apparent that redsensitive emulsion 22 is separated from the line elements 24 and 27 of greenand red-sensitive emulsions by a layer of insulating material and also that the line elements 24 of green-sensitive emulsion are separated from the line elements 27 of blue-sensitive emulsion by insulating material. Also, it will appear that the insulating material covers elemental portions of the redand green-sensitive emulsions which remain uncovered by any other emulsion. Removal of the insulating material from these justmentioned portions may be accomplished by dipping the negative photosensitive element 29 into methanol for about three seconds and removing methanol from the negative photosensitive element by means of a squeegee.

While the use of insulating layers has been set forth as a convenient and efiicient penetration control means, it will be appreciated that a suitable control may be obtained by other practices. In this regard it is to be kept in mind that, generally speaking, formation of a transfer image proceeds with the negative element and the imagereceptive material maintained in contact with each other until positive image formation in the image-receiving layer has been completed. Under these conditions, penetration of processing composition through a screen element and into emulsion underlying said screen element is immaterial insofar as concerns the formation of dye stain in the positive image, provided this penetration of processing composition does not result in the transfer of the coupler of the underlying emulsion to the image-receiving layer during the time necessary to complete the processing essential for the formation of the multicolor positive image.

Penetration of the processing composition into the negative element is controllable by practices Which will be well understood to the art. For example, penetration control may be effected by the thickness of each emulsion forming the different screen elements in the embodiment of the invention disclosed in Figs. 1 and 2, as well as by the selection of emulsions which are of themselves difiicult to penetrate, or a combination of both of these practices may be employed.

As it is well understood, gelatin becomes swelled when Wet. Increase of thickness of an emulsion due to swelling, when wetted with processing composition, may also be utilized as a control means whereby a retarding factor is introduced into the time necessary for processing composition to penetrate into an emulsion and to be returned therethrough for transfer purposes.

In addition, various materials may be added to an emulsion whereby to retard its permeability. Such materials should be compatible with gelatin and, as examples thereof, mention may be made of gum arabic and pol inyl alcohol in appropriate proportions.

In another embodiment of the negative photosensitive element, a sensitive screen structure is employed which is of the type having elemental portions built up of two layers or strata as heretofore mentioned. A negative photosensitive element 30 of this character, suitable for two-color reproduction, is illustrated in Figs. 3 and 4 and comprises a support 31, similar to those previouslynlennamed, a layer 32 containing a color-forming developing agent and a coupler for cyan, a red-sensitive silver halide photosensitive layer 33, insulating material in the form of dots 34 superposed on the outer surface of the red-sensitive emulsion layer 33 in a screen pattern and containing a color developer and upon which a green sensitive silver halide emulsion, having a coupler for magenta incorporated therein, is superposed to provide sensitive portions 35 covering each dot 34 of insulating material.

The element 30 is formed by successively coating, casting, or otherwise applying the layers 32 and 33 onto the support 31, following which a layer of the insulating material, from which dots 34 are subsequently formed, is applied over the entire outer surface of the layer 33. Dots 35 of green-sensitive emulsion and magenta coupler are then applied over a layer of insulating material from a suitable printing roll to provide a geometrical pattern formed of green-sensitive dots 35 over the outer surface of the element 30.

As may be noted, green-sensitive dots 35 are spaced apart with respect to each other and consequently will cover only a portion of the outer surface of the insulating material applied as a coating over the red-sensitive emulsion layer 33. The insulating material which is not covered by green-sensitive dots 35 is removed. As a result, the completed photosensitive element 30 will have an appearance like that illustrated in Figs. 3 and 4, wherein portions of the red-sensitive emulsion 33 are illustrated as uncovered between adjacent green-sensitive dots 35 which are supported on portions of insulating material 34 substantially equivalent in area to the base of each greensensitive dot 35.

It will thus be apparent that each red-sensitive elemental portion in the film structure of Figs. 3 and 4 comprises a layer or stratum 32 which contains developing agent and coupler and on which a layer or stratum 33 of red-sensitive emulsion is supported, while each greensensitive component comprises a stratum of insulating material 34 having a color developer incorporated therein and upon which there is supported a layer or stratum of green-sensitive emulsion 35 which contains a coupler.

It will also be apparent that the red-sensitive and greensensitive elemental portions, upon removal of the insulating material therebetween, will have their respective outer surfaces uncovered so that liquid processing composition spread over the outer surface of the element as a whole may penetrate into each individual sensitive elemental portion. However, due to the insulating strata 34, the liquid processing composition which penetrates into the greensensitive dots 35 will not penetrate into red-sensitive emulsion 33 located directly under the dots.

Material for forming a layer 32 is prepared from the following mixture:

Grams 2-amino-5-diethylaminotoluene monohydrochloride 0.5 2,4-dichloro-l-naphthol 0.5 Cellulose acetate hydrogen phthalate 4 The above mixture is added to 100 cc. of solvent comprising 80% acetone and 20% methanol and is cast or coated in a relatively thin layer upon the support 31.

The emulsion layer 33 comprises a conventional red-sensitive emulsion which, as noted, is applied over the layer 32 by any conventional practice.

The insulating material is provided from a solution of the following proportions: /2 cellulose nitrate6 grams; ethyl acetate90 cc.; to which is added a color developer in a suitable solvent, specifically 0.8 gram of 2-amino-5-diethylaminotoluene monohydrochloride in cc. of methanol.

The green-sensitive dots are formed by adding a solution of an appropriate coupler to a green-sensitive emulsion of high solids content, i.e., about 40%. For this purpose, a magenta coupler, specifically 3.5 cc. of a solution of 1.5 grams of p-nitrophenylacetonitrile in 50 cc. of

Mi ethylene glycol is added directly to 50 grams of the greensensitive emulsion. As previously stated, the green-sensitive composition may be applied onto the element 30 by a printing roll. Spaced-apart dots are provided on such a roll in a symmetrical pattern and are of such predetermined diameter and arrangement that material printed on the outer surface of the element 3% will cover about 50% of a unit area on said surface.

The two-color element of Fig. 4 is completed by removing the insulating material between the green-sensitive elemental portions or dots 35 as by wiping the outer surface of element 30.with methanol. Since the coupler incorporated in the green-sensitive dots 35 is soluble in methanol, it has been found desirable to incorporate a small amount of the coupler in the methanol wiping liquid to avoid leaching coupler from the dots 35.

A suitable blue-absorbing filter, as for example one of the filter materials previously mentioned, is used in conjunction with the red and green elemental portions of the photosensitive element 30. This filter material may be incorporated in the dilferently sensitive emulsions or may be applied to the photosensitive element 30 in the manner described in connection with the element 10.

As previously mentioned, layer 32 of the photosensitive emulsion 30 comprises cellulose acetate hydrogen phthalate in which a developer and a coupler are incorporated. Cellulose acetate hydrogen phthalate is an enteric material, i.e., a material which is water insoluble but which is alkali soluble. An enteric material is preferred in the formation of the layer 32 since moisture contained in the red-sensitive emulsion layer 33, when cast, will permeate into the layer 32 if the latter layer is of a watersoluble or water-permeable material and may cause developing agent and coupler to be introduced into the emulsion. It is desired to avoid this condition since developing agents are readily susceptible to oxidation in aqueous solution and when oxidized act to desensitize the emulsion. Furthermore, the combination of coupler with developing agent is more susceptible to auto-oxidation than either component by itself. Other examples of suitable enteric materials include any easily saponified organic film-forming material such as shellac and Japan wax.

it is to be noted that the insulating material which provides the dotlike insulation 34, in addition to carrying a color developer for the green'sensitive emulsion, also functions to keep the color developer out of the emulsion when the emulsion is cast, yet is able to yield developer to the alkaline solution of liquid processing composition while it further functions to shield the red-sensitive emulsion from contact with components of the green-sensitive elemental portions. Although the insulating material 34 is ditficultly penetrable by liquids, some penetration below and adjacent to the surface thereof will occur when it is contacted by an alkaline solution. This condition is readily taken care 0 fby incorporating a larger quantity of the developer in the insulating material than is normally required to carry out pnotographic processing so that a sufiicient amount of developer may be extracted from the insulating material for this purpose. Shielding of the red-sensitive emulsion is, of course, assured by control of the thickness of the insulating material 34 so that liquid processing composition will not penetrate completely through a layer thereof.

A film unit for carrying out the practices of the invention comprises any of the previously described negative photosensitive elements 10, 20 or 30, and an imagereceptive material such as the positive image-receiving element 40 illustrated in Fig. 5 wherein a unit comprising a photosensitive element 10 and an image-receiving element 40 is diagrammatically shown in the course of processing. The positive sheet or receiving material of the image-receiving element as comprises an image-receiving or base layer 41 of opaque or transparent material which has its surface coated with a thin layer or stratum 42 of a permeable material such as gelatin. An appropriate oxidizing agent is adapted to be incorporated in either the image-receiving layer 41 or the permeable stratum 42. of positive element 40.

In instances where the color process is carried out with the use of conventional couplers and color developers, preferred materials for the image-receiving layer comprise baryta paper, i.e., a support having a baryta coating thereon, and papers such as those known in the art as imbibition paper and dye transfer paper. Any material dyeable from alkaline solutions may, however, be employed for image-receiving layers in all embodiments of the invention, such materials including water-permeable plastics or water-permeable, reversible, film-forming organic' colloids capable of having high viscosity characteristics and appreciable jelly strength. Specific examples of other dyeable layers are regenerated cellulose; polyvinyl alcohol with or without plasticizers; cellulose acetate with filler; an appropriate nylon such as N-methoxymethyl hexamethyl adipamide; partially hydrolyzed polyvinyl acetate; sodium alginate; cellulose ethers, such as methyl cellulose, or other derivatives, such as sodium carboxymethyl cellulose or hydroxyethyl cellulose; papers; proteins, such as glue; carbohydrates, such as gums and starch; and mixtures of such materials where they are compatible. When the above materials are transparent they may, if desired, be mounted on an opaque base, or, a colloidal pigment may be incorporated in such material to renderthe same opaque.

Support materials, when employed to support an imagereceiving or base layer, may be any material of the character used as a support for conventional photographic film and papers. The materials mentioned as suitable for use as image-receiving layers may also be employed as the support in the negative elements 10, or 30.

A wide variety of oxidizing agents, adapted to be incorporated by imbibition in the image-receiving layer or in a gelatin coating thereon, are suitable for use in putting the invention into practice, although their selection will be dependent upon their ability to oxidize the developing agent without substantially affecting the dye formed as a result of the color-forming reaction between oxidized developing agent and coupler.

Particularly useful oxidizing agents may be found in the readily reducible compounds of the polyvalent heavy metals which have their polyvalent metallic element in higher valent form, and especially in the salts of such compounds. Examples thereof may be found in compounds of copper, antimony, uranium, manganese and iron wherein the metallic element is in higher valent form. The compounds having polyvalent metallic elements in higher valent form are reduced by unreacted developing agent which, as a result, becomes oxidized.

Preferred polyvalent metallic compounds are cupric salts and, as specific examples thereof, cupric sulfate, chloride, acetate and stearate are noted. Of these examples of cupric salts, cupric sulfate is preferred. Cupric sulfate and potassium thiocyanate provide a highly useful oxidizing agent which may be introduced into the positive image-receiving layer 41 or the coating 42 by the successive imbibition of these materials in said element followed by washing. It is believed that as a result of this last-noted treatment, the positive element contains some cupric hydroxide and some copper thiocyanate.

In addition, aerial oxidation may be utilized for the purpose of oxidizing unreacted developing agent in or on the image-receiving or base layer to effect positive image formation.

In a specific example, a positive image-receiving element 40 is prepared by coating a surface of baryta paper with a 10% gelatin solution after which the element is treated, as by imbibition, with a 0.25% solution of cupric sulfate whereby to incorporate an oxidizing agent inthe gelatin layer. A positive image-receiving element of this character has proved satisfactory when used with liquid if a processing composition in which the alkali is sodium hydroxide.

The liquid processing composition employed in carrying out the invention with any of the negative and positive elements described herein comprises an aqueous alkaline solution of sufficient alkalinity to permit the developing agent to perform its developing function. A viscosity-increasing compound constituting a filmforming material of the type which, when spread over a water-absorbent base, will form a relatively firm, solid film, is preferably included in the liquid processing composition to assist in spreading the composition in a uniform film between the layers of the film units theretofore described. A preferred film-forming material is a high molecular weight polymer as, for example, a polymeric, water-soluble ether inert to an alkali solution such as hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other film-forming materials or thickening agents may be employed when their ability to increase viscosity is substanially unaffected when left in solution for long periods of time. The film-forming material is preferably contained in the processing composition in suitable quantities to impart to the composition a viscosity in excess of 1000 centipoises at a temperature of approximately 24 C. and preferably of the order of 1000 to 200,000 centipoises at said temperature.

A liquid processing composition suitable for processing any of the negative photosensitive elements 10, 20 or 30, in conjunction with a positive image-receiving element 40, comprises the following ingredients in the proportions indicated.

Sodium carboxymethyl cellulose (medium viscosity) grams 6 Sodium hydroxide do 0.5 Water cc As indicated, although such practice is not as preferred, the invention may be carried out by the use of a processing liquid which includes the developer in solution therein in instances where each color-providing reagent incorporated in the elemental portions of the photosensitive element is characterized by being reactable with the oxidation product of the developer, as is the case for reagents such as the coupler materials theretofore discussed in detail as well as the complete dyes previously mentioned as possessing a coupling function or an ability to react with the oxidation product of a color developer. Where this last-mentioned practice is followed, the liquid, when permeated into each light-sensitive elemental portion, carries the developer With it.

As previously mentioned, a positive and negative element may be conveniently processed by bringing them into face-to-face contact while spreading the liquid processing composition therebetween. Processing in this manner is facilitated by the use of fracturable container means adapted to carry the liquid processing composition. A container of this character is shown at 44 in Fig. 5 and is adapted to be positioned transversely of and adhered to the surface of the positive sheet material 40, i.e., the permeable layer 4-2, or it may be adhered to the surface of the negative photosensitive element. Container 44 is of a length approximating the width of the film unit and is constructed to carry sufficient liquid to effect negative image formation in an exposed imagearea of the negative photosensitive element 10, 2%} or 30 and positive image formation in corresponding image areas of the image-re ceiving layer 41. In use, a container 44 is adapted to be positioned between the negative photosensitive element and the positive image-receiving element so that it will lie adjacent the edges of the corresponding image areas in those elements which are to be processed by the liquid content of the container. When the film unit is of the roll film type, a plurality of containers are employed, one for'each corresponding pair of successive image areas in 17 the photosensitive element and in the image-receiving element.

The container 44 may be formed from composite sheet material comprising an inner layer which is substantially chemically inert to the liquid composition used for processing the film unit, an intermediate layer which is substantially impervious to vapor, and an outer or backing layer which can be readily adhered to some layer of the film unit. Materials for the inner layer of the containers may be found among the polyvinyl acetals, of which polyvinyl butyral and polyvinyl acetal itself are examples, while the intermediate layer may comprise metal foil such as lead or silver foil, and the outer layer may comprise a suitable paper such as kraft paper. A container may be formed by folding such a composite sheet upon itself, adhering the free edges of the folded sheet together at one end and on a side thereof and, after filling the container, sealing the open end thereof by adhering the remaining free edges together.

In the use of all embodiments of the invention, the negative photosensitive element 10, 20 or 30, while in a spread or spaced-apart condition with respect to the positive image-receiving element 40, is adapted to be exposed and then brought into contact with the image-receiving element 40 for processing. It is preferable to expose the negative material from the emulsion side whereby to prevent geometric reversal of the positive image and to maintain good definition. It is therefore desirable to hold the negative photosensitive element 10 or 21} or 30 and the positive image-receiving element 40 together at one end thereof by fastening means, not shown, but comprising hinges, staples or the like, in such manner that the photosensitive element and the negative material may be spread apart as shown inFig. 5, yet may also be brought together as indicated towards the left in Fig. 5.

When the film unit is of the roll film type, the photosensitive element 10 or 20 or 30 and the positive imagereceiving element 40 are wound into separate rolls with the free ends of said rolls connected together, in the manner previously described, and the negative and positive elements are threaded through pressure rolls 43 which are illustrated in Fig. and which form a part of camera apparatus not shown in detail. This permits the photosensitive element and the positive image-receiving element 40 to be arranged in spaced-apart relation so that the individual image areas of the photosensitive element may be successively located within the exposure chamber of suitable camera apparatus while corresponding image areas of the positive sheet material are located outside of the exposure chamber whereby the photosensitive element may be exposed through the emulsion side or face thereof. With regard to suitable camera apparatus, reference is made to the Polaroid Land Camera, Model 95, as well as to United States Patent 2,455,111, issued to Joseph F. Carbone and Murry N. Fairbank, and to United States Patent No. 2,435,717, issued to Edwin H. Land.

Following exposure, a tensional or pulling force is applied to a portion of the film unit which extends to the left of the pressure rolls 43 whereby to pull the exposed image area of the negative photosensitive element and corresponding image area of the positive image-receiving element 41 through the rolls 43. These rolls fracture the container 44, as it passes therebetween, by the application of mechanical stress and cause the liquid contents of the container to be released and spread between the negative and positive sheet materials. At the same time, the pressure rolls 43 cause the photosensitive element and the positive image-receiving element 40 to be brought together, as illustrated, to the left of the rolls 43. Thus, the processing of the film unit is made possible either in a hand camera or as the result of ejec' tion of a film unit from a hand camera.

The formation of positive multicolor images when using any of the various types of negative photosensitive elements disclosed herein, may be understood with specific reference to the processing of a two-color film unit such as that illustrated in Fig. 5 as comprising a negative photosensitive element 10, a positive image-receiving element 40 and a container 44, shown in association with drawing rolls 43 of suitable camera apparatus. As pointed out, the elemental portions of the photosensitive element 10 are, for the purpose of a detailed explanation of the invention, assumed as each having a reagent incorporated therein which comprises an appropriate coupler material and also as having incorporated therein. an appropriate color developer, although as previously noted a color developer which is usable with each of the coupler materials may be dissolved in the processing liquid carried by the container of the film assembly.

Exposure to a colored subject of an image area of the photosensitive element 10, lying to the right of the container 44, will result in the formation of latent image in the parts of each line element 15 of red-sensitive emulsion explosed to light of a wavelength lying within the half of the visible spectrum which includes red radiation and will also result in the formation of latent image in parts of each line element 14 of green-sensitive emulsion exposed to light of a wavelength lying within the half of the visible spectrum which includes blue radiation. It will thus be appreciated that, under these conditions, a latent negative image is formed in each set of line elements or elemental portions of the photosensitive element 10. One such latent image is representative of the red component of the subject and the other latent image is representative of the blue component of the subject.

Following exposure of an image area of the photosensitive element 10, the film unit is pulled between the pressure rolls 43 whereby to fracture container 44 and bring the photosensitive element 10 and positive image-receiving element 40 into superposed relation, while releasing and spreading the liquid processing composition in a uniform thin layer between and in contact with the superposed elements 10 and 40. When the liquid processing composition is spread between the photosensitive and image-receiving elements 10 and 40, it migrates into both elements. Since the outer face of the photosensitive element 10 is composed of individual areas of red-sensitive and green-sensitive emulsions which are uncovered and which comprise the surface of the line elements 1 4 and 15, it will become apparent that penetration of the liquid processing composition into each line element will take place substantially concurrently and through the exposure face thereof. It should be realized that while the surfaces of the line elements 15 are shown as considerably depressed below the surfaces of the line elements 14, this condition is greatly exaggerated for the purpose of illustration. In actual practice, since the emulsions are themselves relatively thin and of the order of about 0.0005 inch in thickness, line elements 14 and 15 will lie substantially in the same plane.

The first processing eifect of liquid processing composition penetrated into the various line elements is to form a dispersion or solution of developing agent and coupler material in the penetrated composition. Where the dissolved developing agent reacts with exposed silver halide contained in a line element 14 or 15, the developing agent becomes oxidized as a function of the amount of silver halide reduced to silver. Developing agent thus oxidized couples with dissolved color-former material adjacent the developing silver grains to form a relatively immobile dye in the exposed portion of the line element.

In all modifications of the invention making use of a combination of couplers and silver halide color developers of the character heretofore described, the developing agent present in a unit of volume of an elemental portion or line element is in a quantity just sufiicient to be completely oxidized by fully developable or completely exposed emulsion in said volume unit. Likewise, in all modifications of the invention making use of a combination of a coupler as a reagent and a silver halide 19 developer of the character heretofore described, coupler material available in a similar unit of volume of an elemental portion or line element is preferably of a quantity just sufficient to be entirely coupled by that amount of developing agent which is oxidized in the development of completely exposed emulsion in said volume unit. Consequently, the coupler material is substantially exhausted by coupling with oxidized developing agent in the area of the highlights of each negative image and is trapped in the negative photosensitive material of the photographic product. In places in the line elements 14 and 15 of the negative photosensitive element 10, where unexposed silver halide grains are present or in places where exposure and consequent development is less than complete, unoxidized developing agent and unreacted coupler material are in solution in proportion to developed silver.

A result of development is therefore to provide, in each group of line elements 14 and 15, an individual negative silver image and a dye image in situ therewith in the fully developed and partially developed regions of each group of line elements and to provide, in the unexposed and partially exposed regions of each group of line elements, an imagewise distribution of unreacted developing agentand unreacted coupler.

It will thus be appreciated that this invention utilizes a screen structure employing principles of additive color processes bythe sensitivities imparted to the line elements oielemental portions providing the screen structure, and at the same time utilizes principles of subtractive color processes by making available for transfer reagents useful for providing colors in the image-receiving layer which are complementary to the additive sensitivities of the emulsions making up the line elements or the elemental portions. In instances wherein the heretofore described couplers are used in providing the desired colors and are employed in conjunction with the heretofore described color developers, an imagewise distribution of unreacted coupler for cyan and u'nreacted color developer is'pr'es'ent in "and available for transfer from undeveloped and partially developed regions of the red-sensitive line elements 15 while an imagewise distribution of'unreacted coupler for magenta and unreacted color developer is present in and available for transfer from undeveloped and partially developed regions in the green-sensitive line elements 14.

At least part of these imagewise distributions of unreacted developing agent and unreacted coupler are diffused through the exposure face of the photosensitive element, the diffusion of each coupler or reagent being restricted to a predetermined depth of the photosensitive element, namely, a depth equal to the thickness of the elemental portion from which the coupler is derived. Couplers and developers in each imagewise distribution thus diffused are transferred to the image-receiving element 40 and are imbibed and deposited therein. Liquid, in the course of transfer from the photosensitive layer to the image-receiving layer, will, at least to some extent, spread or diffuse sidewise or laterally. This condition is inherent in any transfer process. In the case of multicolor work, sidewise diffusion may be advantageously em ployed to cause an overlapping or intermingling on the positive image-receiving element of color-forming components transported from adjacent elemental portions of the screen structure of the negative material. This overlapping of color-forming components is essential in order to obtain subtractive mixtures of dyes needed to form the multicolor image on the image-receiving element.

In this regard, the dimensions of the elemental portions of the negative are preferably chosen so that the sidewise diffusion will provide an overlap of color-forming components from adjacent elemental portions which is approximately equal to the width or equivalent dimens'ion of the widest or largest elemental portion of the screen pattern. Thus each individual solution of colorforming components from each elemental portion will be deposited over a surface area of the image receivin'g layer which is greater in magnitude than the surface area of the screen structure from which the solution originates. The extent of the overlap is controlled by the spacing employed between the negative and positive elements while undergoing processing and will be proportional to the width or other controlling dimension of the largest elemental portion of the negative photosensitive element.

The spacing or distance apart of the negative and positive elements will, of course, be dependent upon the thickness of the liquid processing composition spread between and in contact with the elements. The thickness of the layer of liquid composition will in turn be dependent, as will be well understood to the art, upon the liquid volume being spread, the viscosity of the liquid, the separation or gap between the pressure rolls or other spreading means, and similar inter-related factors.

Developing agent, transported to the positiveimag'ereceiving element in the liquid of each imagewise distribution, will contact the oxidizing agent carried in the imagereCeiving element 40 and become oxidized whereby coupling is initiated between oxidized developing agent and unrea'cted couplers dissolved in the liquid imbibed into the image-receiving material. As a result, the image-receiving layer 40 is provided with positive color component images of the negative component images formed in the photosensitive element 10. These positive component images are, respectively, cyan and magenta components of a multicolor image and will be suitably registered due to the controlled overlap of the transferred color-forming components.

Imbibition time, namely the time the exposed negative element 10 and the image-receiving element 40 are kept in contact after the spreading of the liquid processing solution, is for about three minutes, following which the image-receiving element is separated from the photosensitive element 10.

The separation of the negative photosensitive element 10 and the image-receiving element 4% may be accomplished by stripping action, and any coating of filmforniing material from the processing composition, adhering to the gelatin layer 42, may be removed or allowed to remain thereon. Image formation, while the negative and positive elements are in contact, is carried out in light to which the emulsions of the photosensitive element 10 are substantially insensitive and may be conveniently carried out by keeping the film unit in the dark by allowing it to remain in the camera apparatus, employed to expose it, for a time sufiicient to permit formation of the multicolor positive image.

Like the negative photosensitive element '10, photosensitive elements 20 and 30 are adapted to be employed in conjunction with a positive image-receiving element 40 and processing of the film unit thus provided proceeds in the manner like that heretofore described.

It may be noted that in the strata arrangement of the element 30 of Figs. 3 and 4, it is necessary for the liquid processing composition to penetrate through each layer containing emulsion and into the layer in back of the emulsion which contains developing agent. As in the case of the other embodiments of negative photosensitive elements, the thickness of the screen structure and the various layers of the element 30 are greatly exaggerated. In practice, the layers 33 and 35, which contain'emulsion, will have a thickness of about 0.0005 inch, while layer 32 and the insulating layer 34, which contain developer, will be extremely thin and will have a thickness of the order of about 0.0001 inch. Consequently, liquid composition permeated into the layers 32 and 34 of developing agent will have little opportunity for sidewise or lateral diffusion within the element 30 so that, following exposure and development of the latent negative images, imagewise distribution of unreacted developing agent and a coupler will be present in each .group of sensitive elemental portions,

It has been indicated that unreacted developing agent in or on an image-receiving layer of a film unit may be oxidized by aerial oxidation. In embodiments of the invention which utilize couplers and one or more color developers, it is possible to omit an oxidizing agent from the positive image-receiving element 40' to create dye images therein by permitting air to effect oxidation of unreacted developing agent in the imagewise distributions of color-forming components on the image-receiving ele ment upon the separation thereof from the negative photosensitive element in the usual manner. Processing of this nature is contemplated by the invention, although use of an oxidizing agent is preferred as it speeds up the oxidation reaction and renders it substantially complete.

In instances where developing agent is omitted from the negative photosensitive layer, an equivalent quantity thereof is dissolved in the liquid processing composition before permeation of the liquid within the film unit. Under these circumstances, overlying line elements in the negative materials of Figs. 1 and 2 will comprise an emulsion and coupler material only, while a developing agent will be omitted from each of the layers '32 and 34 of Figs. 3 and 4. A liquid processing composition which contains developing agent is not as satisfactory as a liquid processing composition without developing agent. Since the liquid processing composition is spread between the interfaces of the negative and positive elements, the presence of developer in the composition at the time of spreading gives an extended opportunity 'to the developing agent to create stain in the highlights of the positive image.

The specific products heretofore illustrated disclose some of the types of photographic structures usable for putting the invention into effect. Variation of these products, both in structure and the methods for producing them, and especially in regard to the photosensitive element, are comprehended as falling within the scope of the invention. By way of explanation, details of these variations will be described in connection with products of a type which utilize coupler materials as reagents and color developers in conjunction therewith and wherein the coupler materials are transferred in unreacted form to the image-receiving layer and there reacted to color the layer. From such details, the employment of reagents other than coupler materials in these variations of the products of the invention will become apparent to those skilled in the art.

Instead of utilizing a negative photosensitive element comprising two or more emulsion compositions arranged on a support in a screen type of pattern, such as the line or dot arrangements disclosed in Figs. 1, 2, 3 and 4, it may be preferable to utilize two or more nonphotosensitive compositions which are applied onto or over a surface of an already formed emulsion layer to the end of obtaining a negative photosensitive element having sensitive elemental portions which are selectively exposable over different parts of the spectrum and wherein each elemental portion is capable of forming a dye having a color complementary to the color of the light employed to expose that elemental portion. The nonphotosensitive compositions each comprise color selector material, such as a filter dye or a sensitizing dye, or a combination thereof, and a coupler which will react with oxidized developing agent to give a dye of an appropriate complementary color.

In general, negative photosensitive elements of this character can be made by the use of nonphotosensitive compositions which allow penetration of the necessary agents into the emulsion on which they are supported or which may be caused to introduce these agents into the emulsion and which form substantially impenetrable coatings on the emulsion layer whereby to prevent the penetration therein of any agent from a subsequently applied photosensitive composition. In instances where these concepts are employed, the developing agent may be incorporated in the nonphotosensitive composition itself or it may be carried in a layer in back of the emulsion layer, i.e., on the side of the emulsion layer opposed to that which carries the nonphotosensitive compositions, or it may be included in the liquid employed for processing the photosensitive element.

By Way of one example, nonphotosensitive compositions of the character just noted and in solvent liquid may be printed in the form of lines or dots or the like onto the outer surface of a panchromatic gelatin emulsion carried by a support to provide one set of screen components thereon. In this instance, the nonphotosensitive compositions each comprise filter dye, a coupler adapted to be coupled to give a dye of a color complementary to the color of the exposing light, a solvent, for both the dye and the coupler, which is capable of swelling the gelatin of the emulsion, and also a binder which preferably is insoluble or capable of being made insoluble in its original solvent or suspending medium after drying or other reaction. Suitable solvents for this purpose include mixtures of alcohols or acetone or methyl Cellosolve with water. A suspension of wax or rubber latex which coagulates on drying, or a suspended powdered resin which can be formed into a continuous film upon melting, may be employed for the binder.

A second set of screen components is provided by printing onto uncovered portions of the panchromatc emulsion layer with a second nonphotosensitive composition, similar in all respects to that heretofore described with the exception that a different coupler is used. The second nonphotosensitive composition will only affect the photosensitive element where the panchromatic emulsion layer remains uncovered by the first printed nonphotosensitive composition. A third composition is then applied to the uncovered portions of the panchromatic emulsion. A binder may be omitted from the third nonphotosensitive composition, which otherwise is similar to the nonphotosensitive compositions described with the exception that the coupler therein is capable of forming a dye of a different complementary color.

The solvent contained in each nonphotosensitive composition will penetrate into the panchromatic layer when the composition is applied onto the layer and will carry the desired agents into the emulsion. In this regard, it is preferable that the coupler for the emulsion be contained in the emulsion while, in the case of a sensitizing dye as a color selector, it is essential that the dye be introduced into the emulsion before exposure. On the other hand, it is immaterial whether a filter dye, if used as a color selector, remain on top of the emulsion or be included therein.

The just-described concept may be further extended by utilizing nonphotosensitive compositions which may 'be preformed into lines or other shapes and, after formation, may be laid down or applied onto the surface of the emulsion layer in a screen pattern. Such compositions may comprise, for example, gelatin, a coupler and appropriate color selector material such as a filter dye and/or a sensitizing dye. No binder need be employed in nonphotosensitive compositions which are adapted to be preshaped before application on the surface of the emulsion layer. Introduction into the supporting layer of the color selector material and coupler from a preshaped nonphotosensitive composition is carried out by coating or wetting or dampening the preformed screen elements with a solvent which will permeate into the nonphotosensitive composition and will carry the desired agents into the emulsion layer.

Green filter dyes or combinations of dyes which are sufficiently absorbing in the blue and red regions of the spectrum are highly inefficient in their green transmission. In some instances, therefore, it may be highly desirable to obtain selectivity for the green-sensitive elemental portions of a negative photosensitive element by the use of sensitizing dyes rather than by the use of filter dyes as previously described. As a further example of the various ways in which this invention may be put into effect, utilization may be made of a color-blind emulsion which is adapted to be specifically sensitized over portions thereof whereby the emulsion as a whole will comprise groups of differently sensitive regions arranged in a screen pattern.

'Nonphotosensitive compositions used in the concept will be similar to those just described in connection with the panchromatic emulsion except that they will contain, when necessary, a sensitizing dye and preferably make use of solvents for the sensitizing dyes and couplers which are alkaline solutions since, in general, the sensitizing action of a sensitizer is more effective in entirely aqueous solutions. Likewise, these nonphotosensitive compositions are similarly applied to the emulsion layer.

Under such circumstances the first composition to be printed on the emulsion need contain only a coupler which can'be "coupled to a dye complementary to blue. The second composition to be printed, however, in addition to a coupler, should contain a sensitizing dye and a yellow filter dye. Binders of the character heretofore described may be used in the formation of the first and second compositions. The third composition requires no binder but is a solution of a sensitizing dye, a coupler and a yellow filter dye. With reference to the use of a yellow filter dye, it is pointed out that yellow dyes are known which are very efiicient in the transmission of red and green light. Yellow dyes of this character are adapted to be associated with the redand green-sensitive elemental portions because of the fact that while these portions have been specially sensitized to red and green light, they are also sensitive to blue light and must be protected therefrom.

This concept may also make use of preformed screen components which are adapted to be laid down on a colorblind emulsion in a screen pattern and which are caused to introduce the color selector into the emulsion layer by Wetting, coating or dampening the surfaces thereof with an appropriate solvent for the sensitizing dyes and couplers employed.

Another general method makes use of optical desensitizing. In this instance a specially sensitized emulsion layer, for example a green-sensitive or red-sensitive emulsion, is employed. A coupler which may be used to form a dye of a color complementary to the sensitivity of the emulsion is incorporated in the layer of the emulsion. A protective layer or resist is then applied onto a surface of the emulsion layer in the form of screen elements, such as spaced apart lines or dots to occupy a third of the area of the emulsion layer. A suitable resist is provided by a cellulose nitrate solution. Following application of the resist, the optical sensitizer and coupler contained in the uncovered two-thirds of the emulsion layer is destroyed by the application of a bleach, such as potassium ferricyanide, which is subsequently removed by washing. The efiect of bleaching is to leave the uncovered two-thirds of the emulsion sensitive to blue light. A nonphotosensitive composition of the character described and containing an appropriate sensitizer is employed to form screen lines or dots over another third of the emulsion and an appropriate coupler is then introduced into the remaining uncovered third of the emulsion in the manner described.

By a still further concept, a mixture of grains .is adapted to be applied over a supporting surface. This mixture is made up of distinctive sets of grains wherein the individual grains in each set are similar but possess different characteristics from the grains in any other set.

The mixture, when applied onto a supporting surface,

provides a mosaic pattern thereon. Each individual grain may comprise a sensitive elemental portion of a negative photosensitive element or it may complete such an elemental portion. Thus, the use of a granular mixture may be adapted to any of the concepts set forth herein for obtaining multicolor images by transfer practices. For example, each individual grain may comprise silver halide emulsion of a character which is sensitive over some particular region or regions of the visible spectrum, a developing agent, a coupler reactable with oxidized developing agent to provide a dye of a color complementary to the color of the light employed for exposing the grain and, if needed, an appropriate filter dye. In another instance, each individual grain may comprise one of the nonphotosensitive compositions heretofore described and these grains will be distributed upon a layer of an appropriate emulsion.

In the foregoing detailed discussion, the practice of the invention has been described in conjunction with the use of the reagents which are transferred to the imagereceiving layer in unreacted condition and which there undergo reaction for coloring said layer. As heretofore indicated, other mechanism for coloring the print-receiving element is comprehended as falling within the scope of the invention. As one such variation, the use of photographic coupling materials as color-providing reagents is extendable to include the concept by which the coloring of the print-receiving layer to provide the desired silver image is provided by the transfer thereto of reagents which are reacted in the photosensitive layer and are used in this reacted condition to provide the color image.

In this regard, it is well known that stabilized diazonium salts readily react in an alkaline environment with certain types of photographic coupler materials to carry out a coupling reaction which provides a colored azo compound or dye. These properties of diazonium salts and materials which will couple therewith are utilizable in the present invention to carry out the concept wherein the image-receiving layer is dyed or colored by reagents which have been reacted in the photosensitive element and which are transferred to the image-receiving layer.

By one practice, this concept is carried out by including in each silver halide elemental portion an appropriate stabilized and diazotized salt, a phenolic or naphtholic type coupler, or a coupler having a reactive methylene group, and a nondiflfusing or immobile silver halide color developer, i.e., a developer which, because of the relatively large size of its molecule, is held substantially fast in each elemental portion against diffusion. Each coupler employed should be of a character which is dispersible or soluble in the processing liquid and reactable with the oxidation product of the silver halide developer and also of a character which is reactable with the stabilized and diazotized salt to provide a compound or dye of a color appropriate for the formation of a color component image and particularly a compound or dye which is soluble in an alkaline processing reagent of the character heretofore described. In instances where the product of the reacted reagent lacks the desired solubility, it is desirable to include a solubilizing group or groups, such as sulfonate groups, on the coupler molecule. An example of a suitable immobile developer is p-diethyl-phenylenediamine which has at least a propyl or butyl group on the carbon ring of the developer.

Following exposure, a multicolor photosensitive element having an appropriate coupler, diazonium salt and developer incorporated in each light-sensitive elemental portion thereof is treated by permeating an alkaline processing liquid into each said elemental portion. This alkaline liquid renders each color developer effective to carry out silver development. .As a result of silver development, coupler material in each elemental portion is immobilized as a function of the development and is formed into a dye in situ with the developed silver. Coupler which remains dispersed in the liquid processing reagent in each elemental portion is available for coupling with the diazonium salt therein to form the desired soluble dye, which latter becomes available in an imagewise .diStIibllfiOIlLfOl transferto ithe .image-receiving layer.

At least part of each compound or dye formed in each elemental portion by reaction of coupler and diazonium salt is transferred to the image-receiving layer and there colors said layer without undergoing further treatment.

It has also been stated that the invention is subject to broad variation by changes in the type of reagents employed. For example, the practice of the invention is not limited to the use of photographic coupler materials as reagents. Thus the concepts of the invention may be alternatively carried out by the incorporation in the lightsensitive portions of a photosensitive element such as those illustrated in Figs. 1 through 4 or any of the elements heretofore described, of reagents:

(1) Which are complete dyes or dyestuffs;

(2) Which are reactable with the oxidation product of a silver halide developer, as by a coupling reaction, to provide a reaction substance that, is substantially immobile or difficultly soluble in processing liquid permeated into the photosensitive element or which may be substantially immobilized in the photosensitive element; and

(3) Which are soluble or dispersible in alkaline processing liquids of the character described and hence diffusible from the photosensitive element to a printor image-receiving layer; and

(4) Which are able to dye or color the print-receiving layer and are used for this purpose in unreacted contdition or which provide, as a product of reaction with oxidized developer, a substance usable for coloring the print-receiving layer and undergo such reaction therein.

In view of the foregoing description regarding the use of conventional coupler materials as reagents for carrying out a multicolor photographic transfer process, the manner of employing complete dyes which possess a coupling function will become apparent. Complete dyes which possess the ability to couple are employable in a photosensitive element in the same manner as the conventional couplers previously mentioned, i.e., they are incorporated in light-sensitive elemental portions which may each comprise a layer one stratum thick as the portions 14 and 15 of Fig. l or which may comprise the composite type of layer shown in Figs. 3 and 4.

Developers useful in conjunction with dyes having a coupling group include color developers of the p-phenylenediamine type and also of aminophenol type. Additionally, bis-benzene-sulfonyl hydrazide type developers, which are known to be good black-and-white developers, are also Particularly useful in conjunction with complete dyes of the nature with which this invention is concerned.

Among the classes from which suitable dyes are available, mention may be made of the monoazo, disazo, triphenyl methane, xanthene, thiazine and anthroquinone dyes. The field of dye materials is further extended by the employment of dye substances of the type which react with oxidized developer and which, in unreacted form, may be colorless in a particular environment, for example an acid environment, but upon change in the environment, for example to an alkaline environment, take on a color change. Dye substances of this type include indicator dyes, leucodyes and carbinols of basic dyes.

Dyes which are particularly suited for reaction with an oxidation product of a conventional color developer, as well as with a developer of the bis-benzene-sulfonyl hydrazide type, are found in those dyes having an open position on a ring, which position is para to a hydroxyl or an amino group, or those dyes having a reactive methylene group. Many suitable dyes coming within this classification are found among the azo, pyrazolone and triphenyl methane dyes, specific examples of which comprise the following waterand alkali-soluble dyes such as Fast Crimson 6BL (Cl. 57), for magenta; Fast Wool Yellow ((3.1. 636), for yellow; Alphazurine 2G 26 (Cl. 712) and Pontacyl Green SX Extra (Cl. 737), for cyan; and Polychrome Blue-Black (Cl. 201) and Rayon Black GSP (which is commercially available from E. I. Du Pont de Nemours & Co., Inc., Organic Chemicals Department),'for black; as well as water-insoluble but alkali-soluble dyes such as 1,5-dihydroxynaphthalene- 4-azobenzene, for magenta; and Benzene Azo Resorcinol (Cl. 23), for yellow.

The substance formed by the reaction of a complete dye and an oxidation product of the developer may possess color characteristics which are substantially the same as the unreacted dye or which are dilferent from the unreacted dye. Uniquely, a developer of the bis-benzenesulfonyl hydrazide type provides an oxidation product which reacts With a complete dye to provide a substance having substantially the same color characteristics as the unreacted dye. On the other hand, the reaction product of a dye and an oxidation product of a standard color developer is a substance which, while it may possess the desired immobility, usually has color characteristics dilferent from the unreacted dye.

It is immaterial whether a coupling reaction is carried out in the image-receiving layer in instances Where the reaction product formed by reacting oxidized developer with the dye is of the same color as the dye, although such a reaction is needed when it is the reaction product only which possesses the desired color. Oxidation of transferred unreacted developer when carried out in the image-receiving layer may be caused by aerial oxidation or by the use of an oxidizing agent incorporated in the image-receiving layer.

Additionally, since complete dyes which possess a coupling function are able to dye the image-receiving layer, they are usable, when of appropriate color, for the formation of the transferred image without the need of their reaction in the image-receiving layer. Under these circumstances, only the color-providing reagent or complete dye is transferred to the image-receiving layer while unreacted developer present in the photosensitive portions of the negative element after silver development is held back or retained therein.

A number of procedures are available for retaining a developer in the photosensitive element. In this regard, developers ,may be employed which possess very low solubility in alkali but have good solubility in a highboiling-point solvent. Methods for incorporating such a developer in the sensitive portions of the photosensitive elements hereof have been previously set forth. Alternatively, a relatively immobile or nondilfusing color developer may be incorporated in the negative element, as for example, a developer having a long chain on its molecule, such as 4-amino-3-n-butoxydiethylaniline.

In addition, employment of a nondiffusing developer makes available for transfer processing, coupling dyes characterized by providing a reaction substance with an oxidation product of a more commonly employed color developer which lacks the desired insolubility in the processing liquid. For example, the oxidation product of the developer, 4-amino-3-n-butoxydiethylaniline, is a long chain molecule which is of nondiifusing nature and when reacted with a coupling dye provides a substance having a large molecule of nondiifusing character.

Furthermore, the transfer of dyes which give rise in the negative element to reaction substances of mobile character may be controlled by the use of a developer such as bis-benzene-sulfonyl hydrazide which gives off a gas in the exposed regions in the photosensitive layer as it becomes oxidized in the development of latent image silver halide to form bubbles in the photosensitive element. These bubbles are in greatest concentration where the exposure and development are greatest and are usable as an additional mechanism to assist in immobilizing dye present in the exposed regions of the photosensitive layer.

As previously mentioned indicator dyes, leuco dyes and '27 carbinol s of basic dyes, i.e., dye substances which are capable of assuming a color change, are usable in the .practice of the'invention. Dye substances of this nature dyes such as 2,5-dinitrophenol, quinaldine red and quinoline blue, having, respectively, a yellow, a red and a blue color, at a relatively high pH but being substantially colorless in a neutral environment. A suitable acid may be added to each emulsion that is employed in the photosensitive element for providing a suitable acid environment therein. Alkali contained in the processing liquid, will, in general, provide the needed alkaline environment for creating the desired color change.

In general, developers and complete dyes are employed in quantities per eachunit portion or part of the photosensitive element which are similar to those used in the case of conventional photographic couplers and color developers. However, excess developer may be employed in instances where the developer is bis-benzene-sulfonyl hydrazide or where the developer is kept out of the print-receiving element. It .is also possible to use dye in excess of that just specified when the complete dye has a sufiiciently low solubility rate.

Formation of a multicolor transfer image by the employment of a photosensitive element which utilizes complete dyes and a developer having an oxidation product reactable with the dyes is carried out following exposure of the photosensitive element by processing similar to that heretofore described in connection with photsensitive elements which employ couplers and a color developer as the materials which participate in color image formation and needs no detailed explanation.

A color developer which is usable with each of the complete dyes in the different elemental portions of the photosensitive element maybe dissolved in the processing liquid carried by the container of the film assembly,

although such practice is not as generally preferred as including the developer in each elemental portion itself.

Further variation of the invention by change in the type of reagents employed permits alternative practice of the broad concepts set forth herein by the incorporation, in the light-sensitive portions of a photosensitive element such as those illustrated in Figs. 1 through 4 or any of the photosensitive elements heretofore described, of reagents:

( 1) Which are dyes themselves and possess a silver halide developing function, i.e., dye developers;

(2) Which, upon development of latent silver halide,

provide a reaction or oxidation product that is substantially immobile or difficultly soluble in processing liquid permeated into the photosensitive element;

(3) Which are soluble or dispersible in an alkaline processing liquid of the character described and hence diffusible from the photosensitive element to a printor image-receiving layer; and

(4) Which are able to dye or color the print-receiving layer without undergoing reaction.

.Individual dye developers of appropriate color are utilized singly not only for negative image formation but for the formation of each positive colorcomponent image. Additionally, a dye developer possesses the advantage of permitting practice of the invention while carrying out but a single reaction in the negative material and without the need for synthesizing a color in the positive element.

Processing of a photosensitive element having dye de- Yclopers associated therein is carried out, following exposure thereof,-in a-ma per similar to that previously described and by permeating a processing liquid into each elemental portion thereof, efiecting the development of exposed silver halide in each portion and immobilizing dye developer as a function of silver development while transferring at least part of the unreacted dye developer from unexposed or less than fully exposed regions of each elemental portion to the print-receiving element and there dyeing the print-receiving element with the transferred dye developer.

No oxidation of the dye developer or other reaction is needed in the print-receiving element. 'While as a result of oxidation a dye developer may undergo a color change, such change is slight. More important is the fact that there is little likelihood of transferred dye developer becoming oxidized by contact with the atmosphere since dye developers in general are oxidizable substantially only by a strong oxidizing agent and at a relatively high pH, as for example, by exposed silver halide in the presence of sodium hydroxide. However, the dye developers named herein are quite stable in air when contained in an environment of'lower pH and particularly of a a neutral or acid pH such as that present in the print-receiving layer in which they are deposited upon transfer.

Dye developers are employed in the photosensitive element in the same manner as the previously mentioned .reagents, i.e., they are incorporated in light-sensitive elemental portions which mayeach comprise a layer one stratum thick as the portions 14 and 15 of Fig. 1 or which may comprise the composite type of layer shown in Figs. 3 and 4.

Dyes of substantially all classes and which possess a developing function are, with certain exceptions, available for use. In this regard, dye developers should not possess constituents, such as those found in sulfide dyes, which are harmful to photographic materials and in instances where the dye portion of the dye developer is of a .nature which tends to desensitize silver halide, suitable well known-precautions should 'be taken for controlling this undesired condition. Subject to these qualifications, any dye may be employed which possesses a developing function, which is soluble in solutions of photographic reagents and provides, as an oxidation product, a substance having a lower solubility than the unoxidized dye developer. i

As particular examples of dyes which are utilizable in carrying out the invention, mention is made of azo dyes and anthraquinone dyes to which one or more hydroquinones have been attached. In this instance hydro- .quinone provides the developing function of the dye. Other suitable dyes include azo dyes to which, as a developing function, an amino naphthol or a p-methylaminophenol has been attached.

In general, dye developers are easily synthesized. The methods of attachment of hydroquinone to a dye molecule may be through amino, sulfonyl or carboxyl groups. The developing function can .beapart of the dye itself, as for example the hydroquinone group in the dye developer, Z-naphthylazohydroquinone. When the developing function is apart of the dye, it will affect the color thereof. However, the developing function can be insulated from the 'dye molecule in such a way that it adds little if any color of its own as for example when hydroquinone is attached through a'sulfonyl group to the dy'e molecule. 7 i

For multicolor image formation, the dye developers are selected for their ability to providecolors useful in subtractive color photography. In this regard, dye developers possessing an appropriate .yellow color are 2- naphthylazohydroquinone' and phenylazohydroquinone. Examples of suitablemagenta color dye developers are 2- hydroxynaphthylazohydroquinone and l-amino-2a apthol- 4-azobenzene. An example of a ,suitablecyan colored dye developer is 1,4-bis-(2,5f-dihydroxyanilino)panthraquinone.

In practicing the invention, it is at times desirable, depending upon the particular photographic emulsion and/ or dye developer which is employed, to add sodium bromide to the processing liquid for the purpose of preventing fogging of the emulsion.

Certain dye developers are subject to color change in accordance with the pH of their environment. For example, dye developers having hydroquinone as a part of the conjugated system are particularly pH sensitive in the absence of sulfonyl or carboxyl groups in the dye developer molecule. Thus, a strong alkaline solution of phenylazohydroquinone is blue while the color of a neutral or acid solution thereof is yellow. Since the dye developer is rendered effective to carry out its development and image-forming functions by solution in an alkaline liquid, some means for attaining a favorable pH value for the environment in which the dye developer is deposited is desirable.

One means for assuring a desired pH value is to employ an hydroxide as the alkali of the processing liquid. Usually, carbonation of the hydroxide after processing and by contact with the air will be efiective to provide the desired reduction in pH in the print-receiving element. Another means is to employ a volatile alkali such as diethylamine in the processing liquid, while further controls reside in the utilization of a material for the printreceiving layer which is difiicultly penetrable by alkali, for example, an appropriate nylon type of plastic or the incorporation in the print-receiving layer of a suitable acid or acid-forming compound.

On the other hand, it should be noted that dye developers in which the developing function, such as hydroquinone, is insulated from the conjugated system or which have one or more acid groups on the dye molecules are dye developers of reduced pH sensitivity.

The principal mechanism for controlling the transfer of dye developer to the print-receiving element is the formation of an insoluble oxidation product. Another control mechanism is provided when the dye developer possesses the ability to tan or harden the carrier material for silver halide.

In general, dye developers having a dihydroxybenzene developing function or a trihydroxybenzene developing function provide the most efficient tanning action for gelatin.

Additionally, a dye developer which possesses a free amino group as part of its developing function may be utilized to harden a carrier material for silver halide such 'as a polymer which is normally permeable to alkaline solutions but which can be made less permeable by a coupling reaction with the dye developer. One specific example of a polymer of this nature is a modified polyvinyl alcohol wherein portions of its chain have been substituted with phenol or naphthol and wherein the substituted phenols and naphthols have open positions for coupling which are para to hydroxyl groups. Another example occurs where the polyvinyl alcohol-has been substituted with a compound containing a reactive methylene group which is available for coupling. The incorporation of light-sensitive silver halide in polymers of the character mentioned is disclosed in US. Patent No. 2,397,864. If the coupling group forms the only substitution of the polymer, the permeability of the polymer to alkaline solution is radically lowered upon coupling with the oxidation product of a dye developer of the character having a free amino group as part of the developing function thereof.

The tanning or hardening of the carrier material for silver halide, as a result of development, provides a .control mechanism which is particularly useful in the formation of multicolor positive prints inasmuch as it permits the use of dye developers in quantities in excess of that required to develop fully exposed unit portions of the photosensitive element and thus permits the transfer of greater quantities of unreacted developers to the printreceiving layer as a means for obtaining a multicolor print of high density and contrast.

In multicolor work carried out with dye developers lacking a tanning function, each developer is employed in a quantity sufficient to develop a fully exposed unit portion of the emulsion with which it is associated. 0n the other hand, where a dye developer carries out a tanning action, it may be used in excess of the quantity just indicated.

As previously mentioned, a dye developer may be utilized to control not only its own transfer but that of an additional reagent or colorant such as a dye of the character previously discussed as possessing a function which will couple with oxidized developer and provide a reaction product which is substantially immobile or which may be immobilized in the photosensitive element. Where such reactants are employed, the dye developer will develop the exposed silver halide in the photosensitive element and its own oxidation product will couple with the unreacted dye present therein, while in portions of the element where no exposure has occurred or which are less than completely exposed, both dye developer and unreacted coupling dye will be transferred to a printreceiving element. This practice makes it possible to substantially double the density of the dye image formed by transfer for the same quantity of exposed silver halide in the photosensitive element. Furthermore, use of a colorant in addition to the dye developer makes it possible to form a mixture of dyes possessing particularly desirable light-transmitting and absorption characteristics.

It may be pointed out that when a multicolor image formation is carried out by the use of dye developers, they are always incorporated in the light-sensitive elemental portions of the photosensitive element since, in addition to providing the desired color, these compounds are also the developers themselves.

While the products and methods of the invention have been described in connection with the production of multicolor positive images, it is possible to achieve a number of modified results by certain variations in the procedures and/or the photosensitive elements employed.

For example, one or more reagents capable of dyeing a dyeable material black may be incorporated in each elemental portion of the multicolor photosensitive element to permit the production of a transfer print which carries a black and white positive record of each color component of a colored object to which the photosensitive element has been exposed.

Black and white records may also be reproduced by utilizing the photosensitive elements described herein to carry out a silver halide transfer process by omitting the reagent used to dye a dyeable layer while employing a conventional black and white developer and a suitable silver halide solvent.

It will thus be appreciated that the photosensitive elements disclosed herein may be employed to provide by transfer on a print-receiving element an image which is a jcomposite record of a colored subject in terms of one or more colors and of silver or in terms of one or more colors and of black dye.

Additionally, the taking elements having selectively exposable e emental portions may be appropriately designed and processed to provide black and white negatives or multicolor negatives and in certain instances may be reversal-processed.

In fact, the taking elements disclosed herein possess a versatility that permits modification thereof to carry out an additive color process. For this purpose, each elemental portion of the taking element, besides silver halide, will preferably comprise a black and white developer, a silver halide solvent and a screen dye of an additive color, i.e., red, green or blue. The screen dye is of a nature which is soluble in alkaline processing liquid but which is unreactable with the developer or the oxidation product thereof as well as with the silver halide solvent. The

.reagepts heretofore described for dyeing a dyeablelayer subtractive colors are omitted from the film unit when carrying out an additive color screen process. When a photosensitiveelement of this nature is processed in conjunction with an image-receiving layer in the manner described, positive silver records of a colored object are produced in the image-receiving layer together with a reproduction of the screen therein effected by the transfer of the alkali-soluble dyes from the negative. For providing an additive color negative of this character, dyes which are insoluble in aqueous alkaline solutions are employed or the screen dyes are suitably protected from solution by the use of plastics or other means.

For the purposeof simplicity, the invention has been illustrated and described in connection with a film unit of the roll-film type. However, all aspects of the invention may be carried out with other types of film, for example with cut film or with film in a pack type of unit.

Throughout the specification and appended claims the expression positive image has been used. Thisexpression should not be interpreted in a restrictive sense since it is used primarily for purposes of illustration, in that it defines the image produced on the image-receiving elemen't'as 'being reversed, in thepositive-negative sense, with respect to the image in the photosensitive element. As an example of an alternative meaning for positive image, assume that the photosensitive element is exposed to actinic light through a negative transparency. In this case the latent image in the photosensitive element will be a positive and the image produced on the image-receiving element will be a negative. The expression positive image is intended to cover such an image produced on the image-receiving layer.

Throughout the specification and claims, the expression superposing has been employed. This expression is intended to cover the arrangement of two layers or elements in overlying relation to each other, either in faceto-face contact or in separated condition and including between them at least one layer or stratum of a material which may be a viscous liquid. i

It is to be noted that while a high viscosity for the liquid processing composition is desirable to assist in its spreading, all aspects of the invention may be successfully'practiced without the use of a film-forming material in the composition. As illustrative of this latter expedient, reference is made to the processing compositions heretofore set forth, all of which are employ'able for process ing purposes by the substitution of water for the sodium carboxymethyl cellulose in a quantity equivalent to such film-forming material. In instances when containers are not employed, a nonviscous processing composition is particularly applicable and maybe applied to the negative material by imbibition or coating practices and may be similarly applied to the image-receiving layer ,before the latter and the negative material are brought into contact.

Since certain changes .may be made in the above products and processes without departing from the scope of the invention herein involved, it is intended that all matter contained in the above'de-scription or shown in the accompanying drawings shall be interpreted :as iilustrative and not in a limiting sense. i i

What is claimed is:

1. A photographic process for forming a multicolor transfe'rimage containing a plurality offimage s in dyes, comprising exposing a photosensitive screen element which comprises a first set of photosensitive portions, each portion including a first reagent and photosensitive silver halide having a peak sensitivity within afirst portion of the visible spectrum, and at least a'second set of photosensitive portions, each portion including a second and different reagent and photosensitive silver halide having a peak sensitivity within a second and different portion of the visible spectrum, each of said reagents becapable of reactin g with a mernber of thegroup coni sisting-of (a) exposed silver halide and (b) a product of the development" of exposed silver halide, and also providing a mobile dye-providing constituent selected from the group consisting of dyes and dye intermediates, said photosensitive portions being mounted in contiguous arrangement wherein the individual portions of each set are interspersed with respect to'each other in a screen pattern with the respective exposure faces of said portions being in side-by-side relation to form, in the aggregate, a surface through which said element is exposable; applying to the exposure surface of said photosensitive element a processing liquid and substantially concurrently permeating the applied processing liquid into each said photosensitive portion, each said photosensitive portion, where permeated by said processing liquid, containing a silver halide developing agent, thereby developing said exposed photosensitive element and immobilizing each said reagent in exposed areas as a function of said development and providing, in undeveloped areas, an imagewise distribution of said dye-providing constituent mobile in said processing liquid; transferring said mobile dye-providing constituents by diffusion from said undeveloped aras through said exposure face of said photosensitive element and said processing liquid to asingle print-receiving layer located in superposed relation to said photosensitive element, depositing said mobile dyeproviding constituents on surface areas of said print-receiving layer which are located generally opposite said photosensitive portions and which areas are in overlapping relation to each other and are each larger than the exposure face of the respective photosensitive portion to which each said surface area is opposite; and forming, by means of said transferred mobile dye-providing constituents, a plurality of dye images, the color characteristics of the dye of each of said dye images being predetermined by the chemical structure'of its respective mobile dye-providing constituent and each said dye so provided possessing a predominant spectral absorption within the region of the visible spectrum to which the photosensitive portion from which said mobile dye-providing constituent is diffused is sensitive.

2. A photographic process as defined in claim 1 wherein each said mobile dye-providing constituent is a dye possessing a predominant spectral absorption within the region of the visible spectrum to which the photosensitive portion from which said mobile dye-providing constituent is diffused is sensitive.

3. A photographic process as defined in claim 1 wherein each said mobile dye-providing constituent is a dye intermediate and is reacted after transfer to said printreceiving layer to form said image dye.

4. A photographic process as defined in claim 1 wherein each said reagent is a dye possessing a predominant spectral absorption within the region of the visible spectrum to which said photosensitive portion is sensitive.

.5. A photographic process as defined in claim 1 wherein'each said reagent is a dye intermediate.

6. A photographic process as defined in claim 1 whereinsaid overlap of mobile dye-providing constituents from adjacent photosensitive portions is approximately equal to the width of the widest of said photosensitive portions.

7. A photographic process as defined in claim 1 wherein said photosensitive'element has three sets of photosensitive portions each having its peak sensitivity, re-

spectively, in the blue, green and red regions of the visible spectrum, and wherein the mobile dye-providing constituents transferred from each said set of photosensitive portions to said print-receiving layer form, respectively, yellow, magenta and cyan dye images.

8. A photographic process as defined in claim 1 including the step of applying said processing liquid by spreading said processing liquid in a layer between the ,e po lre surface of said photosensitive element and a surface of said print-receiving layer during the superpositioning of said photosensitive element and said printreceiving layer.

9. A photographic process as defined in claim 1 including the step of separating said print-receiving layer from superposed relationship with said photosensitive element at some stage of said process after said mobile dyeproviding constituents have been transferred to said printreceiving layer.

10. A photographic process as defined in claim 1 wherein said silver halide developing agent is included in said photosensitive portions prior to application of said processing liquid.

11; A photographic process as defined in claim 1 wherein said silver halide developing agent is contained in said processing liquid at the time of its application to said photosensitive element.

12. A photographic process as defined in claim 1 wherein each said reagent is a photographic color coupler reactable with the oxidation product of said silver halide developing agent to provide said image dye.

13. A photographic process as defined in claim 12 wherein said color coupler forms a nondiffusible reaction product upon coupling with the oxidation product of said silver halide developing agent formed in developed areas as a function of said development, said process including the steps of diffusing unreacted portions of said silver halide developing agent and said color coupler from undeveloped areas of each said portion to said print-receiving layer, oxidizing said transferred silver halide developing agent, and reacting the oxidation product of said silver halide developing agent with said color coupler diffused from the same undeveloped area as silver halide developing agent to form said image dye.

14. A photographic process as defined in claim 13 wherein said transferred silver halide developing agent is oxidized by an oxidizing agent carried by said printreceiving layer.

15. A photographic process as defined in claim 1 wherein each said photosensitive portion comprises a mixture of said silver halide and said reagent.

16. A photographic process as defined in claim 1 wherein each said photosensitive portion comprises superposed starata of which a first stratum comprises said photosensitive silver halide, and a second and different stratum includes said reagent, said first stratum being located between a support and said first stratum.

17. A photographic process as defined in claim 1 wherein said peak sensitivity possessed by at least one of said sets of photosensitive portions is imparted thereto by a light-filtering material provided as part of said photosensitive portion.

18. A photographic process as defined in claim 1 wherein each said reagent is a color couper, said silver halide developing agent has an oxidation product reactable with said color coupler, said process including the steps of immobilizing each said color coupler in developed areas by reaction thereof with said oxidation product of said silver halide developing agent to form a nondilfusible, immobile reaction product, transferring said color couper present in undeveloped areas, by diffusion, to said print-receiving layer and reacting said transferred color coupler with a diazonium salt to form said image dye.

19. A photographic process as defined in claim 1 wherein said photosensitive portions comprise individual grains and said screen pattern comprises a mixture of said grains to provide a mosaic.

20. A photographic process as defined in claim 1 wherein at least one photosensitive portion of said first set of photosensitive portions is located above a photosensitive portion of said second set of photosensitive portions, and said transfer of mobile dye-providing constituents is effected substantially to the exclusion of dyeproviding constituent associated with said underlying photosensitive portion.

21. A photographic process as defined in claim 20 wherein the depthwise permeation of said processing liquid is substantially limited to said first-mentioned photosensitive portion.

22. A photographic process for forming a multicolor transfer image containing a plurality of images in dyes, comprising exposing a photosensitive screen element which comprises a first set of photosensitive portions, each portion including a first reagent and photosensitive silver halide having a peak sensitivity within a first portion of the spectrum, and at least a second set of photosensitive portions, each portion including a second and different reagent and photosensitive silver halide having a peak sensitivity within a second and different portion of the spectrum, each of said reagents providing, in the absence of development, a diffusible dye-providing constituent selected from the group consisting of dyes and dye intermediates, said photosensitive portions being mounted in contiguous arrangement wherein the individual portions of each set are interspersed with respect to each other in a regular, screen pattern with the respective exposure faces of said portions being in side-by-side relation to form, in the aggregate, a surface through which said element is exposable;; developing said exposed photosensitive element and thereby providing in undeveloped areas of said portions, as a function of said development, an imagewise distribution of said dilfusible dye-providing constituent; transferring said diffusible dyeproviding constituents by diffusion from said undeveloped areas to a single print-receiving layer located in superposed relation to said photosensitive element; said trans fer being effected to the substantial exclusion of said reagents present in developed areas of said portions; forming, by means of said transferred diffusib le dye-providing constituents, a plurality of dye images, the color characteristics of the dye of each of said dye images being predetermined by the chemical structure of its respective dye-providing constituent; and separating said print-receiving layer from said photosensitive element after said transfer.

23. In a photographic product, the combination which comprises a photosensitive screen element including a support, a first set of photosensitive portions mounted on said support, each said portion including a first reagent and photosensitive silver halide having a peak sensitivity within a first portion of the spectrum, and at least a second set of photosensitive portions also mounted on said support, each portion including a second and different reagent and photosensitive silver halide. having a peak sensitivity Within a second and different portion of the spectrum, each of said reagents being capable of providing, in the absence of development, :a diffusible dyeproviding constituent selected from the group consisting of dyes and dye intermediates, said photosensitive portions being mounted in contiguous arrangement, wherein the individual portions of each set are interspersed with respect to each other in a regular, screen pattern with the respective exposure faces of said portions being in side-by-side relation to form, in the aggregate, a surface through which said element is exposable; said product further comprising a print-receiving layer superposable with respect to said photosensitive portions for receiving, by diifusion transfer, said dilfusible dye-providing constituents; said product further comprising a silver halide developing agent and rupturable container means holding a processing liquid in which said silver halide developing agent is soluble; said photosensitive element, said print-receiving layer and said rupturable container being so held together as to permit at least a portion of said print-receiving layer and said photosensitive element to be superposed with said container positioned so as to be capable, upon being ruptured, of releasing its liquid content between said photosensitive element and print-receiving layer; said processing liquid being capable, upon permeation into said photosensitive portions, of initiating development "of said photosensitive element and alsoof fe'tfecting diffusion of said diffusible dye-providing 7 constituents from said undeveloped areas to saidprint-receiv- V layer; said .difiusible dye-providing constituent being port, each portion including a second and diiferent reagent :and photosensitive silver halide having a peak sensitivity Within a diiferent portion of the visible spectrum, each offsaid reagents being capable of reacting with a member of the group consisting of (a) exposed silver halide and (b) a product of the development of exposed silver halide and also providing a mobile dye-providing conistituent selected from the group consisting of dyes and jclye intermediates, ;said photosensitive portions being mounted in contiguous arrangement, wherein the indi v.vidual portions of each set are interspersed with respect to each other in a screen pattern with the respective eX- posure faces of said portions being in side-by-side relation to form, in the aggregate, a surface through which -said photosensitive element is exposable, each said reagent being capable ofbeing immobilized in exposed areas of said photosensitive portions as a function of silver development, each said reagent being further capable of proyiding, in undeveloped areas, a diffusible dye-providing constituent; said product further comprising a print-receiving layer which is superposable with respect to said photosensitive element; said product further comprising a silver halide developing agent and rupturable container means holding a processing liquid permeable into said photosensitive portions and upon permeation therein to initiate development, said silver halide developing agent being soluble in said processing liquid; said photosensitive element, said print-receiving layer and said rupturable container being so held together as to permit at least a portion of said print-receiving layer to be brought into superposed relationship with said exposure surface of said photosensitive element, and said rupturable container being so positioned as to be capable, upon being ruptured, of releasing its liquid content between said photosensitive element and said print-receiving layer; said diifusible dyeproviding constituent being mobile in said processing liquid and being capable, upon transfer by dilfusion from undeveloped areas of said photosensitive portions through said processing liquid to said print-receiving layer of forming an image in dye, the color characteristics of each said image dye being predetermined by the chemical structure of its respective diffusible dye-providing constituent, each said image dye so provided possessing a predominant spectral absorption within the region of the visible spectrum to which the photosensitive portion from which said diffusible dye-providing. constituent is diffused is sensitive.

'25. A photographic product as defined in clain i- 24 wherein each said photosensitive portion'of said element has a silver halide developing agent incorporated-therein.

26. A photographic product as defined in claim 24 wherein said silverhalide developing agent is contained in said processing liquid in said rupturable container.

27. A photographic product as defined in claim 24 wherein each said diifusible dye-providing constituent is a dye.

28. A photographic product as defined in claim 24 wherein each said reagent comprises a photographic color coupler reactable with the oxidation product of said silver halide developing agent.

29. A photographic product as defined in claim 24 wherein a photosensitive portion of said first set of photosensitive portions is positioned in overlying relationship with a photosensitive portion of said second set of photosensitive portions.

30. A photographic product as defined in claim 24 wherein said photosensitive element includes three sets of photosensitive portions having their peak sensitivities, respectively, in the blue, green and red regions of the spectrum, the difiusible dye-providing constituent provided in undeveloped areas of said sets of photosensitive portions being capable of providing, when transferred to said print-receiving layer, image dyes which are, respectively, yellow, magenta and cyan in color.

31. A photographic product as defined in claim 24 wherein said photosensitive and said print-receiving layer are adapted to be spaced apart, when in superposed relationship during processing, a distance suflicient to cause said transferred diffusible dye-providing constituents to be disposed upon areas of said print-receiving layer which are in overlapping relation to each other and are each larger than the exposure face of the respective photo sensitive portion from which diffusible dye-providing constituent is diffused, whereby subtractive mixtures of dyes are obtained.

32. A photographic product as defined in claim 31 wherein said photosensitive element and said print-receiving layer are adapted to be spaced apart a distance sufiicient to cause an overlap of image dyes, which overlap is approximately equal to the width of the widest photosensitive portion.

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Classifications
U.S. Classification430/212, 430/511, 430/222, 430/236
International ClassificationG03C8/02, G03C8/08
Cooperative ClassificationG03C8/08
European ClassificationG03C8/08