|Publication number||US3674478 A|
|Publication date||Jul 4, 1972|
|Filing date||Dec 17, 1970|
|Priority date||Dec 17, 1970|
|Publication number||US 3674478 A, US 3674478A, US-A-3674478, US3674478 A, US3674478A|
|Inventors||J Michael Grasshoff, Lloyd D Taylor|
|Original Assignee||Polaroid Corp|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (32), Classifications (17)|
|External Links: USPTO, USPTO Assignment, Espacenet|
July 4, 1972 J. M. GRASSHOFF ETAL 3,674,478
NOVEL PRODUCTS AND PROCESSES Filed Dec. 17. 1970 SUPPORT CYAN DYE DEVELOPER LAYER RED-SENSITIVE SILVER HALlDE EMULSION LAYER INTERLAYER MAGENTA DYE DEVELOPER LAYER GREEN-SENSITIVE SILVER HALIDE EMULSION LAYER INTERLAYER YELLOW DYE DEVELOPER LAYER BLUE- SENSITIVE SILVER HALIDE EMULSION LAYER AUXlLlARY LAYER PflMAGE-RECEIVING LAYER KSPACER LAYER L NEUTRALIZING LAYER s UPPORT INVENTORS J. MICHAEL GRASSHOFF and BY LLOYD D. TAYLOR Emma Zndd W ATTORNEYS United States Patent Omce 3,674,478 Patented July 4, 1972 US. Cl. 96-3 44 Claims ABSTRACT OF THE DISCLOSURE Integral negative-positive film units adapted for forming color transfer images, which film units include a novel compound which releases a development restrainer 1n the presence of alkali and which may be defined as a quinoneor naphthoquinone-methide precursor containing a development restrainer moiety.
BACKGROUND OF THE INVENTION Various diffusion transfer systems for forming color images have heretofore been disclosed in the art. Generally speaking, such systems rely for color image formation upon a differential in mobility or solubility of a dye image-providing material obtained as a function of development so as to provide an imagewise distribution of such material which is more diifusible and which is therefore selectively transferred, at least in part, by diffusion, to a superposed dyeable stratum to impart thereto the desired color transfer image. The differential in mobility or solubility may for example be obtained by a chemical action such as a redox reaction or a coupling reaction.
The dye image-providing materials which may be employed in such processes generally may be characterized as either (1) initially soluble or diffusible in the processing composition but are selectively rendered non-difl'usible in an imagewise pattern as a function of development; or (2) initially insoluble or non-diffusible in the processing composition but which are selectively rendered diifusible in an imagewise pattern as a function of development. These materials may be complete dyes or dye intermediates, e.g., color couplers.
As examples of initially soluble or ditfusible materials and their application in color diffusion transfer, mention may be made of those disclosed, for example, in US. Patents Nos. 2,647,049; 2,661,293; 2,698,244; 2,698,798; 2,802,735; 2,774,668; and 2,983,606. As examples of initially non-diffusible materials and their use in color transfer systems, mention may be made of the materials and systems disclosed in US. Pats. Nos. 3,443,939; 3,443,940; 3,227,550; 3,227,551; 3,227,552; 3,227,554; 3,243,94 and 3,445,228.
In any of these systems, multicolor images are obtained by employing a film unit containing at least two selectively sensitized silver halide layers each having associated therewith a dye image-providing material exhibiting desired spectral absorption characteristics. The most commonly employed elements of this type are the so-called tripack structures employing a blue-, a greenahd a red-sensitive silver halide layer having associated therewith, respectively, a yellow, a magenta and a cyan dye image-providing material.
A particularly useful system for forming color images by diffusion transfer is that described in US. Pat. No. 2,983,606, employing dye developers (dyes which are also silver halide developing agents) as the dye image-providing materials. In such systems, a photosensitive element comprising at least one silver halide layer having a dye developer associated therewith (in the same or in an adjacent layer) is developed by applying an aqueous alkaline processing composition. Exposed and developable silver halide is developed by the dye developer which in turn becomes oxidized to provide an oxidation product which is appreciably less diifusible than the unreacted dye developer, thereby providing an imagewise distribution of ditfusiblc dye developer in terms of unexposed areas of the silver halide layer, which imagewise distribution is then transferred, at least in part, by diffusion, to a dyeable stratum to impart thereto a positive dye transfer image. Multicalar images may be obtained with a photosensitive element having two or more selectively sensitized silver halide layers and associated dye developers, a tripack structure of the type described above and in various patents including the aforementioned US. Pat. No. 2,983,606 being especially suitable for accurate color recordation of the original subject matter.
In diffusion transfer processes of this type employing an integral multilayer negative processed with a common processing composition, the dye image-providing material difiusing from an underlying photosensitive layer must necessarily pass through at least one other overlying photosensitive layer. Thus, for example, in systems employing dye developers, if the unoxidized dye developer diffusing from an underlying layer enters an overlying silver halide, there is as much likelihood that this difusing dye developer from the underlying layer will react (develop the silver halide layer to which it has dilfuscd) as there is that the dye developer initially associated with this layer will react.
To illustrate this problem, reference may be made to the aforementioned tripack multilayer element comprising a red-, a greenand a blue-sensitive silver halide layer having associated therewith, respectively, a cyan, a magenta and a yellow dye developer. Assuming that, in a given area of the element, exposure is effected only of the green-sensitive silver halide layer, theoretically, and ideally, this exposed area should be developed by the associated magenta dye developer which is in turn oxidized, so that only cyan and blue dye developer should be transferred by diffusion to the dyeable stratum. If the magenta dye developer has substantially completed this development of the developable green-sensitive silver halide prior to arrival of the unoxidized diffusing cyan dye developer, no harm will be done. On the other hand, if the diffusing unoxidized cyan dye developer diffuses into the greenscnsitive layer while appreciable undeveloped but developable green-sensitive silver halide is still present, this cyan dye developer will react (develop), Since it will not distinguish between developable silver halides of different color sensitivity. This reaction with the wrong silver halide gives rise to the phenomenon referred to as cross talk which is evidenced by producing multicolor transfer images having reduced color separation. In the instance given, this is manifested by less cyan density caused by unwanted immobilization of diffusing cyan dye developer by reaction with the red-sensitive silver halide layer and probably increased magenta density due to the inopportunity for the magenta dye developer to react as intended and hence be immobilized. The same phenomenon is noted with cyan and/or magenta dye developer diffusing through the blue-sensitive layer en route to the dyeable stratum. The total result of this cross-talk is the production of a color print having something less than optimum faithful or accurate color rendition of the subject matter to be reproduced.
As is described and claimed in US. Pat. No. 3,265,498, this problem may be obviated by employing a development restrainer to cause the developable silver halide remaining after a predetermined time following application of the processing composition to be rendered undevelopable, so that unoxidized dye developer diffusing through an overlying silver halide layer other than the one to which it was initially associated in the film unit will not be immobilized by development of developable silver halide contained therein. Since this reagent effectively restIains or arrests further development of develop able silver halide after this predetermined period, which may, for example, be somewhere on the order of five to twenty seconds, such reagents employed for this purpose may be referred to as development restrainers and are so designated in the present application. While such reagents frequently will have characteristics similar to reagents commonly referred to as antifoggants, they perform a function different from what is normally contemplated as the function of an antifoggant, i.e., their function is not to reduce the fog density in unexposed areas, although under some circumstances they may also perform this function to a small degree.
Reagents which are particularly suitable for use as development destrainers are those which will form products or complexes with undeveloped silver halide, whether exposed or unexposed, but at least with exposed silver halide, which products are substantially less developable by a silver halide developing agent, e .g., by the dye developer, and which are substantially insoluble, and hence essentially undevelopable, i.e., developable only with difficulty. As examples of useful development restrainers, mention may be made of heterocyclic mercaptans such as mercaptotetrazoles and mercaptobenzothiazoles, e.g., lphenyl-S-mercaptotetrazole, Zanercaptobenzothiazole, etc.
In order to obtain the desired predetermined period during which development is effected without interference from the development restrainer, this reagent should be employed in a chemical form or in a physical location such that its availability to the developable silver halide is limited or restricted, e.g., as a result of the distance through which it must diffuse to reach the developing silver halide, or as a consequence of a significantly lower diffusion rate than the developing agents. Where the development restrainer is at least initially substantially slower in diffusion than the developing agent, e.g., the dye developer, as for example, as a result of the inclusion of a relatively long chain alkyl group or other such substituent, the development restrainer may be positioned in a layer of the multilayer photosensitive element. However, the preferred development restrainers are characterized as being readily diffusible in the processing composition, e.g., an aqueous alkaline solution, and hence must be located sufliciently remote physically so as not to interfere with the desired development. This is typically accomplished by incorporating the reagent in the image-receiving element adapted for placement in superposition with the photosensitive element during development and the resulting color transfer image formation. It may be placed in the dyeable stratum itself, in an overlying layer or in an underlying layer.
The present invention is directed to integral negativepositive film units for forming color images by diffusion transfer, i.e., those film units containing a negative or photosensitive component and a positive or 'image-receiving component in the same structure, as distinguished from those color diffusion transfer systems wherein the photosensitive and image-receiving elements are separate structures adapted to be brought in superposition at some time after photoexposure, e.g., during processing. In particular, it is directed to film units and systems of this nature employing dye image-providing materials such as those mentioned above and disclosed in the aforementioned illustrative patents wherein it is desired to include a relatively mobile development restrainer in the film unit, e.g., in the dyeable stratum or an associated layer. Of particular interest are those integral or composite film units which are adapted for forming a color reflection print viewable without separation from the remainder of the film unit and which will be described in detail hereinafter. In general, such film units comprise two or more light-sensitive layers and associated dye image-providing material, e.g., the aforementioned tripack structure, a superposed dyeable stratum and means for applying a reflecting layer between the photosensitive strata and the dyeable stratum so as to mask effectively the photosensitive strata and to provide a background for viewing the dye image formed on the overlying dyeable stratum, without separation, by reflected light.
With such film units, it is also desirable to employ a development restrainer in the dyeable stratum or in an associated layer, e.g., in a layer positioned on the side of the dyeable stratum opposed from the photosensitive strata. However, it has been found that attempts to provide a readily soluble and diffusible development restrainer in such a unitary structure presents certain inherent problems not found when the restrainer is incorporated in an image-receiving element adapted to be maintained separate from the photosensitive element until placed in superposition for development and diffusion transfer image formation. Specifically, it has been found that where the development restrainer is incorporated in the positive structure in such unitary film units, a portion of this reagent tends to diffuse during the shelf life of the unit from the layer in which it was incorporated to one or more of the light-sensitive layers, thereby restraining the desired development of exposed and developable areas. In other words, this premature and unwanted diffusion places the reagent in contact with the photosensitive layer or layers prior to application of the processing composition rather than at the desired predetermined interval after development has been initiated, which in turn causes improper dye transfer and the resulting loss of quality in the transfer image. This problem may be referred to as contamination caused by unwanted diffusion of the reagent from the layer in which it Was positioned at some time between preparation of the film unit and its use. It may also be characterized as being an instability of the film unit, specifically an instability of the layer containing the development restrainer.
It is to this problem to which the present invention is directed.
SUMMARY OF THE INVENTION The objectives of this invention are accomplished by including in an appropriate layer of such integral negative-positive film units, as will be detailed hereinafter, a novel compound which is initially non-difiusible but which releases a development restrainer in the presence of alkali, which compound may be defined as a quinone or naphthoquinone-methide precursor containing the development restrainer moiety. They may also be defined as phenols or naphthols (including protected derivatives thereof) having the development restrainer bonded to a nuclear carbon atom through a methylene (CH substituent in a position ortho or para to the hydroxyl group.
These novel compounds may be represented by the formula:
(ANCHOR) 11-1 0 H2-R ES RES represents the development restrainer moiety, e.g., the radical of a development restrainer of the formula: HRES;
ANCHOR represents an anchoring or ballasting substituent such as is described, for example, in US. Pat. No. 3,443,940, e.g., an alkyl containing at least ten carbon atoms, such as decyl, dodecyl, stearyl, oleyl, etc., linked directly to the aromatic nucleus or indirectly through an appropriate linking group such as a CONH, adkylene-CONH- or I substituent, an aromatic ring, e.g., of the benzene or naphthalene series, or a heterocyclic ring, which rings may be either bonded to a single carbon atom of the aromatic nucleus formed by the X atoms or fused thereto by being bonded to a pair of adjacent carbon atoms; a polymeric substituent, e.g., a high polymer backbone; or ANCHOR may be a plurality of .short chain radicals which together provide the anchoring moiety; and
n is l or 2.
If desired, the benzene or naphthalene nucleus of the novel compounds of this invention may contain other substituents providing particular desired functions, e.g., a substituent which will retard or slow down the hydrolysis rate and hence control the rate or time of release of the photographic reagent.
BRIEF DESCRIPTION OF THE DRAWING The figure is an enlarged, fragmentary, diagrammatic, sectional view of a film unit contemplated by this invention.
DESCRIPTION OF PREFERRED EMBODIMENT In the preferred embodiment, the film unit is a socalled tripack employing dye developers as the dye imagproviding matrials, and the novel compound containing the development restrainer moiety is disposed in a layer of the positive component of the film unit. It may, for example, be disposed in a layer on the side of the dyeable stratum opposed from the photosensitive strata. Most preferably, the development restrainer employed is selected from the list of known heterocyclic mercaptan development restrainers, the restrainer being bonded to the methylene substituent through the S atom of the mercapto substituent.
As was mentioned previously, the invention relates to so-called integral negative-positive film units for use in preparing color transfer images and, more particularly, to the employment of development restrainers in such film units.
A primary object of this invention, therefore is to provide novel film units of the foregoing description and systems employing them to produce color images.
Another object is to provide novel means for incorporating a development restrainer in such film units.
Still another object is to provide novel integral negative-positive film units wherein the positive and/or negative component contains a compound of the foregoing description which in the presence of alkali releases a difiusible development restrainer at a desired time interval after application of an alkaline processing composition.
Yet another object is to provide novel film units adapted for preparing a color transfer image in a layer which is viewable, without separation, as a reflection print.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the product possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.
For a further understanding of the nature and objects of this invention reference should be had to the following detailed description taken in conjunction with the accompanying drawing.
As was mentioned previously the present invention is directed to integral negative-positive film units, e.g., photographic products wherein the negative component (lightsensitive layer or layers and any associated strata) and positive component (receiving layer and any associated strata) are contained together as a unitary structure so that two components are laminated or otherwise secured in physical juxtaposition as a single structure. Generally, such film units comprise a plurality of essential layers including at least one light-sensitive silver halide and associated dye image-providing material and a dyeable stratum. Film units intended tto provide multicolor images comprise two or more selectively sensitized silver halide layers each having associated therewith an appropriate dye image-providing material exhibiting desired spectral absorption characteristics. As was heretofore mentioned the most commonly employed negative components for forming multicolor images are of the tripack structure containing a blue-, a greenand a red-sensitive silver halide layer having associated therewith in the same or in a contiguous layer a yellow, a magenta and a cyan dye image-providing material respectively, Interlayers or spacer layers may if desired be provided between the respective silver halide layers and associated dye imageproviding materials.
As was heretofore mentioned the present invention is directed in particular to those integral negative-positive film units adapted for forming color transfer images viewable without separation, i.e., wherein the positive compo nent containing the dye transfer image need not be separated from the negative component for viewing purposes. in addition to the aforementioned essential layers, such film units further include means for providing a reflecting layer between the dyeable stratum and the negative component in order to mask effectively the silver image or images formed as a function of development of the silver halide layer or layers and any remaining associated dye image-providing material and to provide a background for viewing the color image formed in the dyeable stratum, without separation, by reflected light. This reflecting layer may comprise a preformed layer of a reflecting agent included in the essential layers of the film unit or the reflecting agent may be provided after photoexposure, e.g. by including the reflecting agent in the processing composition. These essential layers are preferably contained on a transparent dimensionally stable layer or support member positioned closest to the dyeable stratum so that the resulting transfer image is viewable through this transparent layer. Most preferably another dimensionally stable layer which may be transparent or opaque is positioned on the opposed surface of the essential layers so that the aforementioned essential layers are sandwiched or confined between a pair of dimensionally stable layers or support members, at least one of each is transparent to permit viewing therethrough of a color transfer image obtained as a function of development of the exposed film unit in accordance with the known color diflusion transfer system such as will be detailed hereinafter. In a particularly preferred form such film units are employed in conjunction with a rupturable container of known description containing the requisite processing composition and adapted upon application of pressure of applying its contents to develop the exposed film unit, e.g., by applying the processing composition in a substantially uniform layer between the dyeable stratum and the negative component. It will be appreciated that the film unit may optionally contain other layers performing specific desired functions, e.g., spacer layers, pH-reducing layers, etc.
Opacifying means may be provided on either side of the negative component so that the film unit may be processed in the light to provide the desired color transfer image. In a particularly useful embodiment such opacifying means comprise an opaque dimensionally stable layer or support member positioned on the free or outer surface of the negative component, i.e., on the surface of the film unit opposed from the positive component containing the dyeable stratum to prevent photoexposure by actinic light incident thereon from this side of the film unit and an opacifying agent applied during development between the dycable stratum and the negative component, e.g., by including the opacifying agent in a developing composition so applied, in order to prevent further exposure (fogging) by actinic light incident thereon from the other side of the film unit when the thus exposed film unit is developed in the light. The last-mentioned opacifying agent may comprise the aforementioned reflecting agent which masks the negative component and provides the requisite background for viewing the transfer image formed thereover. Where this reflecting agent does not by itself provide the requisite opacity it may be employed in combination with an additional opacifying agent in order to prevent further exposure of the light-sensitive silver halide layer or layers by actinic light incident thereon.
As examples of such integral negative-positive film units for preparing color transfer images viewable without separation as reflection prints, mention may be made of those described and claimed in U.S. Pats. Nos. 3,415,644, 3,415,- 645, 3,415,646 and 3,473,925; as well as those described in copending applications Ser. Nos. 782,056, now Patent 'No. 3,573,043 and 782,075, now Pat. No. 3,573,044, filed Dec. 9, 1969, 65,084, filed Aug. 19, 1970, all in the name of Edwin H. Land; and Ser. Nos. 39,646, now Pat. No. 3,594,165, and 39,666, now Patent No. 3,594,164, of H oward G. Rogers, filed May 2-2, 1970.
In general, the film units of the foregoing description, e.g., those described in the aforementioned patents and/ or copending applications, are exposed to form 3. developable image and thereafter developed by applying the appropriate processing composition to develop exposed silver halide and to form, as a function of development, an imagewise distribution of diffusible dye image-providing material which is transferred, at least in part by dilfusion, to the dyeable stratum to impart thereto the desired color transfer image, e.g., a positive color transfer image. Common to all of these systems is the provision of a reflecting layer between the dyeable stratum and the photosensitive strata to mask effectively the latter and to provide a background for viewing the color image contained in the dyeable stratum, whereby this image is viewable without separation, from the other layers or elements of the film unit. In certain of these systems, this reflecting layer is provided prior to photoexposure, e.g., as a preformed layer included in the essential layers of the laminar structure comprising the film unit, and in others it is provided at some time thereafter, e.g., by including a suitable lightreflecting agent, for example, a white pigment such as titanium dioxide, in the processing composition which is applied between the dyeable stratum and the next adjacent layer to develop the latent image and to form the color transfer image.
The dye image-providing materials which may be employed in such processes generally are selected from those materials heretofore mentioned and disclosed in the illustrative patents which were initially soluble or diifusible in the processing composition but which are selectively rendered non-diffusible as a function of development or those Which are initially insoluble or non-difi'usible in the processing composition but are selectively rendered diffusible as a function of development. These materials may be complete dyes or dye intermediates, e.g., color couplers.
An illustrative integral negative-positive film unit contemplated by this invention is shown in the illustrative drawings as comprising, as the essential layers, a layer 13 of cyan dye developer, red-sensitive silver halide emulsion layer 14, interlayer 15, a layer of magenta dye developer 16, green-sensitive silver halide emulsion layer 17, interlayer 18, yellow dye developer layer 19, blue-sensitive silver halide emulsion layer 20, auxiliary layer 21, imagerecei-ving layer 22, spacer layer 23, and a pH-reducing or neutralizing layer 24. Layers 13-21 comprise the negative component and layers 22-24 comprise the positive component. These essential layers are shown to be confined between a. dimensionally stable layer or support member 12 which is preferably opaque so as to permit development in the light and dimensionally stable layer or support member 25 which is effectively transparent to permit viewing of a. color transfer image formed as a function of develop ment in receiving layer or dyeable stratum 22.
Layers 12 and 25 are preferably dimensionally stable liquid-impermeable layers which when taken together may possess a processing composition solvent vapor permeably sufficient to effect, subsequent to substantial transfer image formation and prior to any substantial environmental image degradation to which the resulting image may be prone, osmotic transpiration of processing composition solvent in a quantity eifective to decrease the solvent from a first concentration at which the color-providing material is difi'usible to a second concentration at which it is not. Although these layers may possess a vapor transmission rate of 1 or less gms./24 hrs/ in. /mil., they preferably possess a vapor transmission rate for the process ing composition solvent averaging not less than about 100 gms./24 hrs/100 inF/mil, most preferably in terms of the preferred solvent, water, a vapor transmission rate averaging in excess of about 300 gms. of water/24 hrs./ 100 inF/miL, and may advantageously comprise a microporous polymeric film possessing a pore distribution which does not unduly interfere with the dimensional stability of the layers or, where required, the optical characteristics of such layers. As examples of useful materials of this nature, mention may be made of those having the af0rementioned characteristics and which are derived from ethylene glycol terephthalic acid; vinyl chloride polymers; polyvinyl acetate; cellulose derivatives, etc. As heretofore noted layer 12 is of sufficient opacity to prevent fogging from occurring by light passing therethrough, and layer 25 is transparent to permit photoexposure and for viewing of a transfer image formed on receiving layer 24.
The silver halide layers preferably comprise photosensitive silver halide, e.g., silver chloride, bromide or iodide or mixed silver halides such as silver iodobromide or chloriodobromide dispersed in a suitable colloidal binder such as gelatin and such layers may typically be on the order of 0.6 to 6 microns in thickness. It will be appreciated that the silver halide layers may and in fact generally do contain other adjuncts, e.g., chemical sensitizers such as are disclosed in U.S. Pats. Nos. 1,574,944; 1,623,499; 2,410,689; 2,597,856; 2,597,915; 2,487,850; 2,518,698; 2,521,926; etc.; as :well as other additives performing specific desired functions, e.g., coating aids, hardeners, viscosity-increasing agents, stabilizers, preservatives, ultraviolet absorbers and/or speed-increasing compounds. While the preferred binder for the silver halide is gelatin, others such as albumin, casein, zein, resins such as cellulose derivatives, polyacrylamides, vinyl polymers, etc., may replace the gelatin in whole or in part.
The respective dye developers, which may be any of those heretofore known in the art and disclosed for example in U.S. Pat. No. 2,983,606, etc., are preferably dispersed in an aqueous alkaline permeable polymeric binder, e.g., gelatin as a layer from about 1 to 7 microns in thickness.
Interlayers 15, 18 and 21 may comprise an alkaline permeable polymeric material such as gelatin and may be on the order of from about 1 to 5 microns in thickness. As examples of other materials for forming these interlayers, mention may be made of those disclosed in U.S. Pat. No. 3,421,892 and the copending applications of Richard J. Haberlin, Ser. No. 854,491, filed Sept. 2, 1969, and Lloyd D. Taylor, Ser. No. 790,648, now Pat.
No. 3,575,700, filed Jan. 13, 1969, etc. These interlayers may also contain additional reagents performing specific functions and the various ingredients necessary for development may also be contained initially in such layers in lieu of being present initially in the processing composition, in which event the desired developing composition is obtained by contacting such layers with the solvent for forming the processing composition, which solvent may include the other necessary ingredients dissolved therein.
The image-receiving layer may comprise any of the dyeable strata heretofore known in the art for preparing color transfer images. It may be on the order of 0.25 to 0.4 mil. in thickness and may, for example, comprise a dyeable polymer such as nylon, e.g., N-methoxymethyl polyhexamethylene adipamide; partially hydrolyzed polyvinyl acetate; polyvinyl alcohol with or without plasticizers; cellulose acetate with filler as, for example, one-half cellulose acetate and one-half oleic acid; gelatin; polyvinyl alcohol or gelatin containing a dye mordant such as poly- 4-vinylpyridine, etc. The receiving layers may, if desired, contain suitable mordants, e.g., any of the conventional mordant materials for acid dyes such as those disclosed, for example, in the aforementioned US. Pat. No. 3,227,- 550; as well as other additives such as ultraviolet absorbers, pH-reducing substances, etc.
While not necessary to the practice of this invention, with the film units employing color-providing materials such as dye developers wherein development is effected in the presence of a processing composition having a relatively high pH, say, for example, on the order of at least 12 to 14, it may be desirable or expedient to provide means for reducing the pH following development to a level wherein the resulting dye image is not adversely affected. The film unit shown in the illustrative drawing shows such pH-reducing means as comprising spacer layer 23 and neutralizing layer 24. The concept of employing such pH-reducing means is disclosed, for example, in US. Pat. No. 3,362,819.
One such system as is disclosed in US. Pat. No. 3,362,819 employs a polymeric acid layer in association with the image-receiving layer. An inert timing or spacer layer is preferably disposed between the polymeric acid layer and the image-receiving layer.
As is disclosed in this patent, the polymeric acid layer comprises polymers which contain acid groups, such as carboxylic acid and sulfonic acid groups, which are capable of forming salts with alkali metals, such as sodium, potassium, etc., or with organic bases, particularly quaternary ammonium bases, such as tetramethyl ammonium hydroxide, or potentially acid-yielding groups, such as anhydrides or lactones, or other groups which are capable of reacting with bases to capture and retain them. The acid-reacting group is, of course, non-diffusi'ble from the acid polymer layer. In the preferred embodiments disclosed, the acid polymer contains free carboxyl groups and the transfer processing composition employed contains a large concentration of sodium and/or potassium ions. The acid polymers stated to be most useful are characterized by containing free carboxyl groups, being insoluble in water in the free acid form, and by forming water-soluble sodium and/or potassium salts. One may also employ polymers containing carboxylic acid anhydride groups, at least some of which preferably have been converted to free carboxyl groups prior to imbibition. While the most readily available polymeric acids are derivatives of cellulose or of vinyl polymers, polymeric acids from other classes of polymers may be used. As examples of specific polymeric acids set forth in the application, mention may be made of dibasic acid half-ester derivatives of cellulose, which derivatives contain free carboxyl groups, e.g., cellulose acetate hydrogen phthalate, cellulose acetatehydrogen glutarate, cellulose acetate hydrogen succinate, ethyl cellulose hydrogen succinate, ethyl cellulose acetate hydrogen succinate, cellulose acetate hydrogen succinate hydrogen phthalate; ether and ester derivatives or cellulose modified with sulfoanhydrides, e.g., with ortho-sulfobenzoic anhydride; polystyrene sulfonic acid; carboxymethyl cellulose; polyvinyl hydrogen phthalate; polyvinyl acetate hydrogen phthalate; polyacrylic acid; acetals of polyvinyl alcohol with carboxy or sulfo substituted aldehydes, e.g., o-, m-, or p-benzaldehyde sulfonic acid or carboxylic acid; partial esters of ethylene/ maleic anhydride copolymers; partial esters of methylvinyl ether/maleic anhydride copolymers; etc.
As previously noted, the pH of the processing composition may be of the order of at least 12 to 14. The acid polymer layer is disclosed to contain at least sufiicient acid groups to effect a reduction in the pH of the image layer from a pH of about 12 to 14 to a pH of at least 11 or lower at the end of the imbibition period, and preferably to a pH of about 5 to 8 within a short time after imbibition, thus requiring, of course, that the action of the polymeric acid be accurately so controlled as not to interfere with either development of the negative of image transfer of the color-providing material. For this reason, the pH of the image layer must be kept at a functional transfer level until dye image has been formed. Where the color-providing material is not dififusible at the lower pH obtained by the polymeric acid layer, the subsequent pH reduction, in addition to its desirable effect upon image light stability, also serves a highly valuable photographic function by substantially terminating further dye transfer.
In order to prevent premature pH reduction during transfer processing, as evidenced, for example, by an un desired reduction in positive image density, the acid groups are disclosed to be so distributed in the acid polymer layer that the rate of their availablity to the alkali i controllable, e.g., as a function of the rate of swelling of the polymer layer, which rate in turn has a direct relationship to the diffusion rate of the alkali ions. The desired distribution of the acid groups in the acid polymer layer may be effected by mixing the acid polymer with a polymer free of acid groups, or lower in concentration of acid groups, and compatible therewith, or by using only the acid polymer but selecting one having a relatively lower proportion of acid groups. These embodiments are illustrated, respectively, in the cited copending patent, by (a) a mixture of cellulose acetate and cellulose acetate hydrogen phthalate and (b) a cellulose acetate hydrogen phthalate polymer having a much lower percentage of phthalyl groups than the first-mentioned cellulose acetate hydrogen phthalate.
It is also there disclosed that the layer containing the polymeric acid may contain a water-insoluble polymer, preferably a cellulose ester, which acts to control or modulate the rate at which the alkali salt of the polymer acid is formed. As examples of cellulose esters contemplated for use, mention is made of cellulose acetate, cellulose acetate butyrate, etc. The particular polymers and combinations of polymers employed in any given embodiment are, of course, selected so as to have adequate wet and dry strength and when necessary or desirable, suitable subcoats are employed to help the various polymeric layers adhere to each other during storage and use.
The inert spacer layer, for example, a layer comprising polyvinyl alcohol or gelatin, acts to time control the pH reduction by the polymeric acid layer. This timing is disclosed to be a function of the rate at which the alkali diffuses through the inert spacer layer. It is there stated to have been found that the pH does not drop until the alkil has passed through the spacer layer, i.e., the pH is not reduced to any significant extent by the mere diffusion into the interlayer, but the pH drops quite rapidly once the alkali diffuses through the spacer layer.
As disclosed in aforementioned US. Pat. No. 3,362,- 819, the presence of an inert spacer layer was found to be effective in evening out the various reaction rates over a wide range of temperatures, for example, by preventing premature pH reduction when imbibition is effected at temperatures above room temperature, for example, at
95 to 100 F. By providing an inert spacer layer, that application discloses that the rate at which alkali is available for capture in the polymeric acid layer becomes a function of the alkali diflusion rate.
However, as disclosed in U.S. Pat. No. 3,455,686 preferably the aforementioned rate at which the cations of the alkaline processing composition, i.e., alkali ions, are available for capture in the polymeric acid layer should be decreased with increasing transfer processing temperatures in order to provide diffusion transfer color processes relatively independent of positive transfer image variations over an extended range of ambient temperatures.
Specifically, it is there stated to have been found that the diffusion rate of alkali through a permeable inert polymeric spacer layer increases with increased processing temperature to the extent, for example, that at relatively high transfer processing temperatures, that is, transfer processing temperatures above approximately 80 F., a premature decrease in the pH of the transfer processing composition occurs due, at least in part, to the rapid diffusion to alkali from the dye transfer environment and its subsequent neutralization upon contact with the polymeric acid layer. This was stated to be especially true of alkali traversing an inert spacer layer possessing permeability to alakil optimized to be effective with the temperature range of optimum transfer processing. Conversely, at temperatures below the optimum transfer processing range, for example, temperatures below approximately 40 F., the last-mentioned inert spacer layer was disclosed to provide an effective diffusion barrier timewise preventing effective traverse of the inert spacer layer by alkali having temperature depressed diffusion rates and to result in maintenance of the transfer processing environments high pH for such an extended time interval as to facilitate formation of transfer image stain and its resultant degradation of the positive transfer images color definition.
It is further stated in the last-mentioned U.S. Pat. No. 3,455,686 to have been found, however, that if the inert spacer layer of the print-receiving element is replaced by a spacer layer which comprises a permeable polymeric layer exhibiting permeability inversely dependent on temperature, that is, a polymeric film-forming material which exhibits decreasing permeability to solubilized alkali derived cations such as alkali metal and quaternary ammonium ions under conditions of increasing tempertaure, that the positive transfer image defects resultant from the aforementioned overextended pH maintenance and/ or premature pH reduction are obviated.
As examples of polymers which were disclosed to exhibit inverse temperature-dependent permeability to alkali, mention may be made of: hydroxypropyl polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyvinyl oxazolidone, hydroxypropyl methyl cellulose, isopropyl cellulose, partial acetals of polyvinyl alcohol such as partial polyvinyl butyral, partial polyvinyl formal, parpolyvinyl acetal, partial polyvinyl propional, and the The last-mentioned specified acetals of polyvinyl were stated to generally comprise saturated aliphatic hydrocarbon chains of a molecular weight of at least 1,000, preferably of about 1,000 to 50,000, possessing a degree of acetalation within about to 30%, to 80% and 10% to 40%, of the polyvinyl alcohols theoretical polymeric hydroxy groups, respectively, and including mixed acetals where desired.
Where desired, a mixture of the polymers is to be employed, for example, a mixture of hydroxypropyl methyl cellulose and partial polyvinyl butyral.
While the acid-containing or neutralizing layer 24 and spacer of timing layer 23 of the foregoing description are shown in the illustrative figures to be disposed between the receiving layer and transparent layer 25', this pH- reducing means may be disposed elsewhere in the film unit and may, for example, be disposed between the receiving layer and layer 12, as is disclosed in the copending 12 application of Edwin H. Land, *Ser. No. 782,056, filed Dec. 9, 1968, and now Pat. No. 3,573,043.
The structural integrity of the film unit may be maintained by an adhesive capability installed between the various layers comprising the laminate. However, the adhesive capability installed between image-receiving layer 22 and auxiliary layer 21 should be less than that between the opposed surfaces of the remainder of the layers forming the laminate so as to permit the processing fluid to be applied therebetween. The laminates structural integrity may also be enhanced or provided by a binding member extending around the edges of the laminate, and maintaining the layers comprising the laminate intact, except at the interface between layers 22 and 21 during distribution of the processing fluid between those layers.
The processing fluid may be contained in a pod or rupturable container of the type shown and described in any of U.S. Pats. Nos. 2,543,181; 2,634,886; 2,653,732; 2,723,051; 3,056,492; 3,056,491; 3,152,515; and the like. In general, such containers will comprise a rectangular blank of fluidand air-impervious sheet material folded longitudinally upon itself to form two walls which are sealed so as to form a cavity for containing the processing composition.
The processing composition may comprise an aqueous alkaline solution having a pH at which the dye developers are soluble and diffusible and an opacifying agent in a quantity sufiicient to mask the dye developers associated with the silver halide emulsions after processing and to provide the requisite background for viewing the color image formed in layer 22. As mentioned before, the concentration of opacifying agent is preferably sufficient to protect the film products silver halide emulsion or emulsions from further exposure by actinic radiation traversing through the dimensionally stable transparent layer 25 after the opacifying agent is applied to the emulsion(s). Accordingly, where layer 12 is opaque, the film product may be rocessed, after distribution of the composition, in the presence of actinic radiation, in view of the fact that the silver halide emulsion or emulsions of the laminate are appropriately protected at one major surface by the opaque processing composition and at the remaining major surface by the dimensionally stable opaque layer. Any edge leakage of actinic radiation incident on the emulsion or emulsions may also be prevented by the use of appropriate means such as opaque binder tapes.
A preferred opacification system to be contained in the processing composition is that described in the co-pen'ding application of Edwin H. Land, Ser. No. 43,782, filed June 5, 1970, comprising an inorganic reflecting pigment dispersion containing at least one optical filter agent at a pH above the pKa of the optical filter agent in a concentration eifective, when the processing composition is applied, to provide a. layer exhibiting optical transmission density about 6.0 density units with respect to incident radiation actinic to the photosensitive silver halide layer and optical reflection density about 1.0 density with respect to incident visible radiation.
In lieu of having the reflecting pigment contained in the processing composition, e.g., as disclosed in the aforementioned copending application Ser. No. 43,782, the reflecting pigment needed to mask the photosensitive strata and to provide the requisite background for viewing the color transfer image formed in receiving layer 22 may be contained initially in whole or in part as a preformed layer in the film unit. As an example of such a preformed layer, mention may be made of that disclosed on the copending applications of Edwin H. Land, Ser. Nos. 846,441, filed July 31, 1965, now U.S. Pat. No. 3,615,421, and 3,645, filed Jan. 19, 1970. The reflecting pigment may be generated in situ as is disclosed in the copending applications of Edwin H. Land, Ser. Nos. 43,741 and 43,742, both filed June 5, 1970.
As was mentioned previously, in accordance with this invention, the desired development restraining function f 1': CHzSHET wherein:
X and Y have the meanings heretofore noted;
The CH -SHET substituent is bonded to a nuclear carbon atom ortho or para to the Y substituent; and
HET represents a heterocyclic ring, particularly a heterocyclio 5-membered ring containing at least one nitro gen atom, e.g., a tetrazole, benzothiazole, etc., including nuclear substituted derivatives thereof, the SHIET moiety being the monovalent radical of a development restrainer of the formula:
HSH1ET Especially useful developer restrainers are those of the mercaptotetrazole and the mercaptobenzothiazole series, the former being most preferred.
As examples of useful compounds within the scope of Formulae A or B, mention may be made of the following:
1-pheny1-5- p-hyd'roxyb enzylthio) -tetraz0le 1-phenyl-5- (o-hydroxyb enzydthio) -tetrazole 3. O O OCH:
l-phenylfipacetoxybenzylthio -tetrazole orr2-s l Ll 1-phenyl-5-(o-acetoxybenzylthio)-tetrazole CHO l-phenyl-B- (2"-hydvoxy-5-flormy-1 benzylthio -tetrazole '1-phenyl-5- (2 '-hyd roxy5 -nitr0benzyl thio) -tetmz ole N? mi ,l
1-phenyl-5- (4 hydroxy-naphthylmelthylthio) -tetm.z0le
1-pheny1-5- (W-hydroxy-marphthylmethylthlo) -tetrazole O O CCH:
1-pl1enyl-5- (4 -acetoxy-naiphthylmethylthio -tetraz 011a 0 O OCH; NN
1-phemyl-5- (42' acetoxy-naphthyflme'thylthjo) -tebra zole O CO 0 02H;
1-tpheu-yl-5- (p-oalthyloxyb enzyl'thio -rtetraz o'le N CHzS l-phenyl-Ei- P-hydroxy fi'dodecylaminodethylhen zylthio) -tetrazole -om-s f l 1-phenyl-5 (2 '-hydlroxy-5' -hexad ecylamidobenzylthio) -te trazole OCCHa CE In general, the compounds of Formulae A and B are readily obtainable by appropriate replacement or substitution reactions. In such reactions it may be, and usually is desirable to protect the phenolic hydroxyl group during the reaction step by which the development restrainer moiety is incorporated. The compound may be employed, i.e., incorporated in the film unit, in this protected form or, in lieu thereof, the protective group may be removed by hydrolysis with acid prior to use in the film unit. Since the protected form must first be hydrolyzed to the corresponding alcohol before the next step in the alkaline hydrolysis reaction wherein the development restrainer is released, it will be appreciated that the protected forms do not release the restrainer as rapidly upon contact with alkali. This may be an advantage or a disadvantage, depending upon the particular film unit, its position in the film unit, and/ or the particular reaction mechanism upon which color transfer image formation is obtained. In other words, where rapid diffusion of the restrainer is desired following application of alkali, the compound should be employed in its phenolic form. On the other hand, where slower diffusion is preferred, it may be advantageous to employ the compound in its protected form.
The following reaction illustrates the preparation of the compounds contemplated by this invention:
followed if desired by hydrolysis in acid:
Further by way of illustration, the following reactions illustrate the preparation of a compound of this invention employing l-phenyl-S-mercaptotetrazole as the restrainer.
The following examples ShOW the preparation of illustrative compounds of this invention.
Example 1 g. of o-hydroxybenzyl alcohol were gradually added while stirring to 45 g. of ice-cooled acetyl chloride. About 30 minutes after the addition had been completed, unchanged acetyl chloride was evaporated using a thin film evaporator. 50 ml. of water Were then added to the residue followed by neutralization by adding solid sodium bicarbonate. This mixture was extracted three times with 50 ml. of ethyl ether (each extraction) and the ether phase was then dried. Vacuum distillation yielded 17 g. of o-acetoxybenzyl chloride, a colorless liquid, B.P. (1.5 mm.) 98l02 C.
Example 2 100 g. of p-hydroxybenzyl alcohol were added in small portions, while stirring, to 300 ml. of ice-cooled acetyl chloride. Upon standing at room temperature overnight, the major portion of excessive acetyl chloride had evaporated and the remainder was removed using a thin film evaporator. The residue was then neutralized by shaking with concentrated aqueous sodium bicarbonate solution. The aqueous phase was extracted twice with 100 ml. of ethyl ether and the combined organic layers were filtered and then dried. Vacuum distillation yielded 81 g. of pure p-acetoxybenzyl chloride, a colorless liquid, B.P. (1.5 mm.) l04l06 C.
Example 3 45 g. of the sodium salt of phenylmercaptotetrazole were dissolved in 500 ml. of acetone. This solution was then filtered and heated to boiling, after which a solution of 41.5 g. of o-acetoxybenzyl chloride (as prepared in Example 1) in 100 ml. of acetone were added. The resulting solution was refluxed for two hours and filtered. The filtrate was evaporated to yield a solid residue which was extracted with warm 3% aqueous sodium bicarbonate solution. After filtration the solid material was washed with water and then dried to yield 64.5 g. of l-phenyl-S- (o-acetoxybenzylthio)-tetrazole (Formula 4), white crystals melting at l03105 C.
Elemental analysis.Calculated (percent): C, 59.0; H, 4.3; N, 17.2; S, 9.8. Found (percent): C, 58.8; H, 4.6; N, 16.9; S, 9.7.
64.5 g. of the compound of Formula 4 (as prepared above) was dissolved in 1.6 l. of methanol, 15 ml. of 10% aqueous hydrochloric acid were added and the solution was then heated while stirring to 55-57 C. in the presence of nitrogen. After two hours 100 ml. of methanol were slowly added to replace methanol which had evaporated. After two more hours the methanol was flushed off using a thin film evaporator. The solid residue was pulverized, extracted with warm dilute aqueous sodium bicarbonate solution, washed with water and then dried. Recrystallization from benzene/hexane yielded 46 g. of l-phenyl-S-(o-hydroxybenzylthio)-tetrazole (the compound of Formula 2), white crystals melting at about 102 C., soluble in methanol and benzene and slightly soluble in water.
Elemental analysis.-Calculated (percent): C, 59.2; H, 4.2; N, 19.7; S, 11.8. Found (percent): C, 59.3; H, 4.3; N, 19.5; S, 11.6.
Example 4 45 g. of the sodium salt of phenylmercaptotetrazole were dissolved in 500 ml. of acetone. This solution was filtered and heated to boiling, after which 41.5 g. of pacetoxybenzyl chloride (as prepared in Example 2) in ml. of acetone were added. The resulting solution was refluxed for two hours and filtered. The filtrate was evaporated to yield a solid residue which was extracted with warm 3% aqueous sodium bicarbonate solution. It was then filtered and the solid material recovered was washed with water and dried in a vacuum oven to yield 72 g. of 1-phenyl-5-(p-acetoxybenzylthio)-tetrazole (the compound of Formula 3), white crystals melting at 7172 C.
Elemental analysis.Calculated (percent): C, 59.0; H, 4.3; N, 17.2. Found (percent): C, 58.9; H, 4.3; N, 17.3.
57 g. of the last-mentioned compound were dissolved in 1.3 1. of methanol. 10 ml. of 10% aqueous hydrochloric acid were added and the solution was heated to 55-57" C. while stirring and in the presence of nitrogen. After two hours 100 ml. of methanol were added slowly to replenish evaporated methanol. About one hour later the methanol was flashed oif using a thin film evaporator. The resulting solid residue was pulverized, extracted with warm dilute sodium bicarbonate solution, washed with water and dried. Recrystallization from benzene/hexane yielded 35 g. of 1-phenyl-5-(p-hydroxybenzylthio)-tetrazole, white crystals melting at -131 C., soluble in methanol and benzene and slightly soluble in water.
Elemental analysis.-Calculated (percent): C, 59.2; H, 4.2; N, 19.7; S, 11.8. Found (percent): C, 59.2; H, 4.4; N, 19.7; S, 11.3.
Example 5 To a solution of 8.7 g. of the sodium salt of l-phenyl-S- mercaptotetrazole in 200 ml. of acetone was added a solution of 6.4 g. of Z-hydroxy-S-formyl-benzyl chloride in 50 ml. of acetone. After stirring for 30 minutes at room temperature, the resulting mixture was filtered and the filtrate was refluxed for 30 minutes, filtered again and the solvent was then evaporated with a thin film evaporator. The solid residue was washed with warm aqueous sodium bicarbonate solution for 15 minutes, filtered, dried and washed with ether to yield 5.5 g. of 1-phenyl-5-(2- hydroxy-S'-formyl-benzylthio)-tetrazole, the compound of Formula 5, white crystals soluble in acetone and methanol, M.P. 168 C. 1.5 g. of Elvanol 70-05 (trademark of E. I. duPont de Nemours & Co. for a low viscosity polyvinyl alcohol) was suspended in a solution of 3.5 g. of the compound of Formula 5 (prepared as described above) and 0.5 ml. of H PO in 30 ml. of glacial acetic acid for 3 hours at 80 C. under nitrogen and with stirring. The temperature was then lowered to 55 C. for 3 days with stirring. The resulting clear yellow solution was then cooled to room temperature, decanted and precipitated into dilute aqueous sodium bicarbonate. It was then washed and dried to yield 2.3 g. of the polymer of Formula 17, soluble in methyl cellosolve.
Elemental analysis.-Calculated (percent): C, 57.7; H, 6.1; N, 7.7; S, 4.4. Found (percent): C, 57.1; H, 6.1; N, 8.1; S, 4.1.
The novel reagents of this invention may be incorporated in the filrn units by forming a. solution of the reagent and the film-forming material comprisingthe matrix of the layer in which it is to be included (along with any other ingredients to be contained in this layer) and then coating this solution by any of the known techniques to provide the desired layer containing the reagent. The precise manner of application per se comprises no part of this invention and will be readily apparent to those skilled in the art. It will be understood, however, that the layer containing the reagent must be alkali permeable so as to permit diffusion of the alkaline medium needed to effect release of the restrainer. The selection of the particular material employed as the matrix will be apparent, particularly since all of the materials customarily em- 1 9 ployed to provide the various layers of the positive and negative components, including those mentioned previously in the description, are typically alkali permeable.
As was heretofore mentioned, these reagents may be advantageously included in the positive component. They may, for example, be included in receiving layer 22, spacer layer 23 and/or neutralizing layer 24 of the film unit shown in the illustrative drawing. They may also be contained in a layer between the dyeable stratum and the spacer or timing layer, e.g., between layers 22 and 23 and/ or in a layer disposed over the dyeable stratum, e.g., auxiliary layer 21 (which while previously referred to for convenience as a layer of the negative component may also be considered as a layer of the positive component in the context of this description) or in a layer positioned between layers 21 and 22. In a particularly preferred form, the reagent is contained in the dyeable stratum or in an underlying layer, Le, a layer disposed between the receiving layer and transparent support 25.
When contacted by alkali, for example, by the aqueous alkaline processing composition, the compound splits ofi the development restrainer and forms the quinone-methide or naphthoquinone-methide in accordance with one of the following illustrative reaction mechanisms:
I CHa-RE S 63:
The following examples show by way of illustration and not by way of limitation the preparation of typical film units contemplated by this invention.
Example 6 On a transparent polyethylene terephthalate film base was coated a 7:3 mixture, by weight, of polyethylene/ maleic acid copolymer and polyvinyl alcohol at a coverage of about 1,000 mgsJft. to provide a polymeric acid layer. Over this was coated a graft copolymer of acrylamide and diacetone acrylamide on a polyvinyl alcohol backbone in a molar ratio of 1:3.2:1 at a coverage of about 750 mgsJft? to provide a polymeric spacer of timing layer. A layer was next applied comprising a mixture of the aforementioned graft copolymer and a compound of Formula 1 at a coverage of 750 mgsJft. of graft copolymer and 72 rugs/ft. of the compound of Formula 1. Finally, a dyeable stratum comprising a 2:1 mixture by weight of polyvinyl alcohol and poly-4-vinylpyridine was coated at a coverage of about 500 mgs./ft. to provide the positive component of the film unit.
Example 7 On a transparent polyethylene terephthalate film base was coated the polymeric acid layer described in Example 6 at the same coverage. Over this was applied a mixture of the graft copolymer described in Example '6 and the compound of Formula 2 at a coverage of about 750 rugs/ft. of the graft copolymer and about 72 mgsJft. of the compound of Formula 2. Finally, the dyeable stratum referred to in Example 6 was applied at a coverage of 500 mgs./ft. to provide a positive component of the film unit.
To prepare an integral negative-positive film unit of the type shown in the illustrative drawing, the positive component prepared in the foregoing illustrative examples is placed in superposition with the negative component and the respective components are then laminated or otherwise maintained together to provide the requisite film unit. If desired it may be taped toegther in laminate form, at their respective edges, by means of a pressuresensitive binding tape extending around, in contact with, and over the edegs of the resulting laminate.
The following example illustrates a typical negative component which may be employed in combination with the aforementioned positive component to provide a composite film unit of this invention.
Example 8 The negative component may be prepared by coating, in succession, on an opaque film base the following layers:
(1) A layer of cyan dye developer dispersed in gelatin and coated at a coverage of about mgs./ft. of dye and about mgs./ft. of gelatin;
(2) A red-sensitive gelatino-silver iodobromide emulsion coated at a coverage of about 225 mgs./ft. of silver and about 50 mgs./ft. of gelatin;
(3) A layer of acrylic latex sold by Rohm and Haas Co. under the trade designation AC-61 and polyacrylamide coated with a coverage of about 100 mgs./ft. of AC-61 and about 5 mgsJft. of polyacrylamide;
(4) A layer of magenta dye developer dispersed in gelatin and coated at a coverage of 70 mgsJft. of dye and about mgs./ft. of gelatin;
(5) A green-sensitive gelatinosilver iodobromide emulsion coated in a coverage of about 120 mgsjft. of silver and 6-0 mgs./ft. of gelatin;
(6) A layer comprising the acrylic latex sold by Rohm and Haas Co. under the trade designation B-15 and polyacrylamide coated in a coverage of about 100 rugs/ft. of B-l5 and about 10 mgsJft. of polyacrylamide;
(7) A layer of a yellow dye developer and the auxiliary developer 4'-methylphenyl hydroquinone dispersed in gelatin and coated at a coverage of about 50 rugs/ft? of dye, about 15 mgs./ft. of auxiliary developer and 50 mgs. /ft. of gelatin;
(8) A blue-sensitive gelatino-silver iodobromide emul- SiOCIIJ coated at a coverage of about 75 mgsJft. of gelatin; an
(9) A layer of gelatin coated at a coverage of about 50 mgs./ft. of gelatin.
The three dye developers employed above may be the following:
a cyan dye developer;
a yellow dye developer.
Film units containing the positive component of this invention were compared with control film units containing a conventional development restrainer, l-phenyl-S- mercaptotetrazole (PMT) in the dyeable stratum or in an underlying layer, i.e., a structure analogous to that described in Example 6.
The following examples show the preparation of these control components.
Example 9 On a transparent polyethylene terephthalate film base was coated the polymeric acid layer referred to in Example 6 at the same coverage, i.e., 1,000 mgs./ft. Over this was applied the graft copolymer referred to in Example 6 at the same coverage, i.e., 750 mgsjft Finally, a mixture comprising a 2:1 mixture by weight of polyvinyl alcohol and poly-4-vinylpyridine was coated at a coverage of about 735 mgs./ft. of this mixture and rugs/ft? of PMT to provide a positive component wherein the development restrainer (PMT) was contained in the dyeable stratum.
Example 10 On a transparent polyethylene terephthalate film base was coated the polymeric acid layer referred to in Example 6 at the same coverage, i.e., 1,000 mgs./ft. Over this was applied a layer of the graft copolymer referred to in Example 6 at a coverage of 750 mgs./ft. A layer was next applied comprising a mixture of this graft copolymer and PMT at a coverage of about 750 mgs./ft. of the graft copolymer and 45 mgs./ft. of PMT. Finally, the dyeable stratum referred to in Example 6 was coated at a coverage of about 500 mgs/ft? to provide a positive component wherein the development restrainer is positioned in a layer beneath the dyeable stratum, i.e., a positive component analogous in structure to that prepared in Example 6.
An integral negative-positive film unit prepared by laminating the positive component as prepared in Example 6 22 to a negative component of the type prepared in Example 8 was compared for contamination with similar control units similar in all respects except that the positive components of the controls were those prepared in Examples 9 and 10. In each instance, exposure times, development procedures, etc., were the same to establish established and accepted test procedures. One set of tests compared the Dmin, and D obtained on storage at room temperature for three days. Since the problem of contamination is greater at higher temperatures and/or humidities, another standard-type test compared the D and D obtained after storage for five days at 100 F. and relative humidity.
-In each instance, after storage, the film unit was exposed for the same time and then developed by applying between the dyeable stratum and the adjacent layer of the negative component a processing composition com prising the following proportions of ingredients:
Titanium dioxide-50.0 gms. Carboxymethyl cellulose3 .4 gms. Potassium hydroxide1l.2 gms. Benzotriazole1.7 gms. 5-hydroxy-4-azabenzimidazole0.35 gm. Phenethyl-a-picolinium bromide1.37 gms.
The density reading for cyan, magenta and yellow dye transfer were then determined to be as follows:
3 days at 5 days at 100 F. room temp. and 80% R.H.
min. mnx. Dmin. Dmnx.
Control with PMT in dyeable stratum:
.17 1. 20 2.11 33 1. 86 .41 1.91 Y .71 1.98 .95 1.75 Control with PMT in layer under dyeable stratum:
C .18 2.46 .19 2.13 38 2. 49 .42 2. 27 .58 2.48 .75 2.27 Film unit with Formula 1 under dyeable stratum:
Comparing first the room temperature test with the heat and humidity storage test for any of the film units, it will be seen that the D (unwanted dye transfer) are higher in each instance, due to greater contamination whereby development is prematurely restrained, thus permitting dye which would normally be able to develop the respective silver halide emulsions layers and hence be immobilized to instead remain mobile and ditfusible and hence transfer. As would be expected, this contamination is most pronounced in the blue-sensitive emulsion layer, the closest one in point of distance to the development restrainer, as is evidenced by the so-called yellow flooding resulting in comparatively high unwanted yellow dye transfer. Thus, for example, in the first control wherein the PMT was in the dyeable stratum, the yellow D were .71 and .95, the latter being at the more extreme storage test, as expected. Placing the PMT more distant as in the second control unit wherein it was positioned in an underlying layer afforded some benefits of lower D with regard to the yellow dye, as noted by the D readings of .58 and .75. No lowering of the D for the cyan and magenta were noted however, although the Dmax, for each dye was up. The film unit containing the compound of Formula 1 showed clearly superior results. The yellow D,,,,,,, of .45 and .67 were appreciably better. The respective Dmax, was also improved.
It should be noted, however, that some contamination was still observed with the compound of Formula 1, as observed, for example, by the higher D in the heathumidity storage test. Accordingly, use of this compound in lieu of standard development restrainers such as PMT does not at present appear to obviate fully the contamination problem. However, this compound is so markedly superior to such standard development restrainers that it is clear that the present invention provides a great improvement in this regard over the prior systems utilizing development restrainers.
In addition to the foregoing storage tests, a temperature latitude series of tests were conducted for the same three film units to determine performance upon development in the cold minutes at 40 F.); at room temperature (3 minutes at 70 F.); and in the hot (2 minutes at 100 'F.). The dye density (D readings for each of the three dyes showed, quite unexpectedly, superior dye densities.
These readings were as follows:
The increased cyan and magenta dye transfer obtained with the film unit of this invention over that obtained, for example, with the control wherein the PMT is in the dyeable stratum, would appear to indicate that the compound of Formula 1 functions more effectively as a development restrainer in eliminating or minimizing the aforementioned problem of cross-talk wherein these dye developers develop the wrong silver halide layer and hence are immobilized where they should be free to transfer. However, it is not clearly understood Why the present invention provides increased yellow dye density in the cold, at room temperature and in the hot. It may be due, at least in part, to a presently unexplained and unaccountable phenomenon whereby the compound of Formula 1 difiuses slower than PMT in the cold, where the restraining action should optimally be slower due to slower dye diffusion rates, and yet faster in the hot where more rapid restraining action is required.
In any event, the temperature latitude series indicates clearly that the film unit of this invention gives overall superior results in terms of desired dye transfer. Taken in conjunction with the previously described superior performance in terms of reduced contamination, it will therefore -'be apparent that the present invention provides a significant advance in the art to which it is directed.
in the foregoing illustrative examples, the reagent containing the development restrainer moiety was incorporated in the positive component of the film unit. In accordance with this invention, the reagent may also be contained in the negative component provided it is incorporated in such a manner that the development restrainer is not released for diifusion to the photosensitive strata too soon in the development process, i.e., before the desired development and imagewise dye distribution formation are substantially efiected. Where the compound is employed in its free hydroxy form, e.g., where the phenolic hydroxy substituent is not protected, the development restrainer may be released too rapidly, unless some physical barrier means is provided to retard or delay contact of the reagent with alkali land/or diffusion of the released restrainer to the photosensitive strata. Thus, for example, in film units of the type described previously, it was determined that incorporation of 39.9 mgs./ft. of the free hydroxy compound of Formula 1 or Formula 2 in a silver halide emulsion layer containing about 150 mgs./ft. of silver and 150 mgs./
24 ft? of gelatin desensitized too rapidly so that no silver image was noted and no transfer image was formed.
However, the necessary time delay in the development process may be obtained by employing a protected derivative in lieu of the free hydroxy compound, e.g., one of the illustrative compounds wherein the Y substituent is a radical which upon hydrolysis provides a hydroxy substituent.
Thus, where as the free hydroxy compound releases the development restrainer in a single reaction step upon application of alkali, as in the reaction mechanism previously illustrated, the protected derivatives require two reaction steps: (1) hydrolysis to form the free hydroxy compound; and (2) the subsequent release reaction providing the development restrainer.
The following example illustrates the preparation of a monochromatic film unit wherein the reagent is included in the silver halide layer.
Example 11 On a transparent polyester sheet was coated a layer containing 50 mgs./ft. of the magenta dye developer shown in Example 8 and 75 rugs/ft? of gelatin; a silver halide layer containing mgs./ft. of silver, 150 mgs./ ft. of gelatin and 45:8 rngsJft. of the p-acetoxy compound of Formula 3 (equivalent by weight to 25 mgs./ ft. of 1-phenyl-5-mercaptotetrazole); and a gelatin overcoat containing 150 rugs/ft. of gelatin to provide a negative component containing a reagent of this invention in the silver halide layer. A similar (control) negative was prepared which diffused only in that it did not contain the reagent. The control negative was developed in superposition with a positive component containing a development restrainer, l-phenyl-5-mercaptotetrazole, in the dyeable stratum similar to that described in Example 9; whereas the test negative containing the compound of Formula 3 was developed in superposition with a similar positive component containing no development restrainer. The data comparing the two negative components with The above results indicate that in overall performance (exclusive of contamination) the control system wherein the development restrainer was in the positive component provided better results. The higher D obtained with the test negative are believed to be caused by the fact that the compound of Formula 3 is releasing the development restrainer too rapidly in terms of the rate of development in the particular system tested. In other words, better results may be obtained if the release rate were slower, e.g., by employing a reagent which hydrolyzes to the free hydroxy compound at a slower rate, or, conversely, it the development rate were increased.
Accordingly, while at first blush it would appear from the foregoing data that no advantage over the prior art is obtained by including a reagent of this invention in the silver halide layer or layers, one skilled in the art will recognize that significant benefits can in fact be obtained. First, in integral negative-positive film units, the stable reagents, e.g., compounds such as that of Formula 3, can be included in the negative component without theproblem of contamination found where a typical soluble restrainer is employed, for example, in the positive component. Secondly, when one contemplates that the addition of as little as 3 mgsJft. of 1-phenyl-S-rnercaptotetrazole in a silver halide layer will substantially totally desensitize so that no image can be obtained, it is significant to note that the addition of the reagent in an amount equivalent to 25 rugs/ft. of 1-phenyl-5-mercaptotetrazole provided a usable image. Thirdly, one skilled in the art will recognize from the foregoing discussion and illustrative data that by selection of the appropriate reagent in combination with the development rate of the particular system will in turn provide the appropriate release rate in the time-rate sequence to achieve optimum photographic results.
In Example 11, a monochromatic negative component was prepared. The following example illustrates the preparation of a multilayer negative component.
Example 12 On a polyester film base was coated the following layers: 1) a layer containing 100 mgs./ft. of the cyan dye developer shown in Example 8, 150 mgs./ft. of gelatin and 22 mgs./ft. of the acetoxy compound of Formula 3; (2) a red-sensitive silver halide emulsion layer containing 19.5 mgs./ft. of gelatin and 140 mgs./ ft. of silver; (3) a latex interlayer similar to Example 8; (4) a layer containing 65 mgs./ft. of the magenta dye developer shown in Example 8, 32 rugs/ft. of gelatin, 7.5 mgs./ft. of 4'-methylphenyl hydroquinone; and 12 mgs./ft. of the acetoxy compound of Formula 3; (5) a green-sensitive silver halide emulsion layer containing 56.4 mgs./ft. of gelatin and 50 mgs./ft. of silver; (6) a latex interlayer; (7) a layer containing 70 mgs./ft. of the yellow dye developer shown in Example 8, 31 mgs./
A negative component was prepared similar to that shown in Example 8, except that the negative component was overcoated with a tenth layer containing 26 mgs./ ft. of the acetoxy compound of Formula 3 and 26 mgs./ ft. of gelatin. When a color transfer image prepared by using this negative component in conjunction with a positive component containing no development restrainer Was compared with a color transfer image prepared by using a similar negative component containing none of the acetoxy compound in conjunction with the positive component containing 1-phenyl-5-rnercaptotetrazole in the dyeable stratum, the results were as follows:
ft. of gelatin, 7.5 mgs./ft. of 4'-methylpheny1 hydroquinone and 11 mgsJft. of the acetoxy compound of Formula 3; (8) a blue-sensitive silver halide emulsion layer containing 46.5 mgs./ft. of gelatin and 65 mgs./ft. of silver; and (9) a layer containing mgs./ft. of gelatin. A control negative component was also prepared similar in all respects except layers 1, 4 and 7 contained none of the acetoxy compound. As in the comparative test of Example 11, the negative component of this invention was employed in conjunction with a positive component containing no development restrainer; whereas the control negative component was employed in conjunction with a positive component containing the development restrainer, l-phenyl-S-mercaptotetrazole in the dyeable stratum. In the usual manner, the red, green and blue densities were determined from transfer images prepared at 75 and 100 F.
The results tabulated are as follows:
The observations taken from the comparative tests of Examples 12 and 13 are generally similar to that derived from Example 11 and previously discussed. However, these three illustrative examples clearly show the adaptability of this invention to the employment of the novel reagents of this invention in the negative component.
It is to be noted that in the illustrative negative components prepared in Examples 11-13 and in the systems employing them, no substantial effort was made to achieve optimum results. The experiments conducted do however show clearly the efficacy of employing such negative components. One skilled in the art will understand that the function of the development restrainer is a time-rate phenomenon wherein the restrainer must be present to function in this capacity at the right time in the particular system employed. This in turn is a function of the development rate.
The film units prepared in Example 12 were also subjected to accelerated aging (six days at 120 F.) and heat-humidity (5 days at 100 F. and 80% relative humidity) storage test conditions prior to use. The red, green and blue densities were determined from color images prepared at 75 F. The readings were as follows:
According, while in the preferred embodiments of this invention, the reagent is incorporated in the positive component, it may also be incorporated in the negative component. Since incorporation in the negative component places the reagent in closer proximity to the photosensitive strata to which it is intended to func- 27 tion, when incorporated in the negative component it must be so disposed in such a manner that it will not be available to perform its development restraining ac tion too early in the development process, e.g., it should not be able to perform its restraining function before substantially all of the exposed and developable silver halide has been developed. While various physical means in the form of temporary barriers to migration of the released restrainer may be suggested to those skilled in the art, particularly in the light of the foregoing description, it will be seen that the requisite delay in release of the restrainer may be accomplished chemically by employment of the compounds wherein the Y moiety is a substituent which must first hydrolyze to the corresponding hydroxy compound before the second stage wherein the restrainer is released. The rate of release may thus be controlled by selection of the appropriate Y substituent, e.g., esters which hydrolyze more or less rapidly, or by the inclusion in the nucleus of the reagent of a substituent which aifects the rate of hydrolysis.
While the present invention has been described in connection with film units adapted for forming a color transfer image viewable, without separation, as a reflection print, it is to be expressly understood that the invention is not restricted thereto. The invention further includes those integral negative-positive film units wherein the negative and positive components are initially maintained together as a unitary structure but where the positive component is to be separated from the negative component following image formation to provide the desired print which may be a transparency or a refiection print. To facilitate this separation, a stripping layer of known description may be employed, i.e., disposed between the dyeable stratum and the next adjacent layer of the negative component.
Accordingly, as used herein and in the appended claims, the term integral negative-positive film uni is intended to define both types of imaging systems and techniques.
Since certain changes may be made in the above product and process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
1. In an integral negative-positive film unit for forming color transfer images including a negative component comprising at least one-light sensitive silver halide layer and an associated dye image-providing material and a positive component containing a dyeable stratum;
the improvement which comprises including in said film unit a quinone-methide or naphthoquinone-methide precursor containing a development restrainer moiety.
2. A film unit as defined in claim 1 wherein said precursor is disposed in said positive component.
3. A film unit as defined in claim 1 wherein said pre-- cursor is disposed in a layer in said positive component, said dyeable stratum being positioned bet-ween said negative component and said layer of precursor.
4. A film unit as defined in claim 1 including means for applying an aqueous alkaline processing composition between said negative and positive comopnents.
5. A film unit as defined in claim 4 including means for applying a layer of a light-reflecting agent between said positive and negative components, said layer of light-reflecting agent being adapted for eifectively masking said negative component and for providing a background for viewing a color transfer image formed in said dyeable stratum, without separation, as a reflection print.
6. A film unit as defined in claim 5 wherein said lightreflecting means comprises a preformed layer disposed in said film unit between said dyeable stratum and said negative component.
7. A film unit as defined in claim 5 wherein said light- 28 reflecting means is applied in a layer between said negative component and said dyeable stratum at some time following photoexposure of said film unit.
8. A film unit as defined in claim 1 wherein said precursor is a compound of the formula:
(ANCHO R) n-1."-
' CH2-RES wherein X represents the atoms necessary to complete a benzene or a naphthalene radical;
Y is hydroxy or a substituent which upon hydrolysis in alkali will provide a hydroxy substituent;
RES is the monovalent radical of a development restrainer of the formula: H-RES, said -CH RES substituent being ortho or para to said Y substituent;
ANCHOR is an anchoring substituent rendering said compound appreciably more non-difiusible than it would be without said ANCHOR substituent;
and n is l or 2.
9. A film unit as defined in claim 8 wherein said dye image-providing material is a dye or dye intermediate which is insoluble and non-diifusible in an aqueous alkaline medium.
10. A film unit as defined in claim 8 wherein said dye image-providing material is soluble and diffusible in an aqueous alkaline medium.
11. In an integral negative-positive film unit for forming color transfer images including a negative component comprising a red-sensitive silver halide layer and an associated cyan image-providing material, a green-sensitive silver halide layer and an associated magenta image-providing material, and a blue-sensitive silver halide layer and an associated yellow image-providing material; and a positive component containing a dyeable stratum for forming a color transfer image from said materials diffusing thereto from said negative component, said negative and positive components being maintained in juxtaposition, said negative and positive components together being contained on a single dimensionally stable layer or being confined between a pair of dimensionally stable layers;
the improvement which comprises including in said positive component a phenol, a naphthol or a protected derivative thereof which upon hydrolysis in alkali will form a phenol or a naphthol, having a development restrainer bonded to a nuclear carbon atom thereof through a methylene substituent in a position ortho or para to the hydroxyl group or the protected hydroxyl group.
12. A film unit as defined in claim 11 including a substantially transparent dimensionally stable layer disposed on the outer surface of said positive component.
13. A film unit as defined in claim 12 including means for applying a light-reflecting layer between said dyeable stratum and said negative component.
14. A film unit as defined in claim 13 wherein said means comprises a preformed layer of a light-reflecting agent.
15. A film unit as defined in claim 13 wherein said means comprises an aqueous alkaline processing composition including said light-reflecting agent.
16. A film unit as defined in claim 15 wherein said processing composition is confined in a rupturable container positioned with respect to said film unit as to be capable, upon rupturing, of discharging said composition in a substantially uniform layer between said dyeable stratum and said negative component.
17. A film unit as defined in claim 12 wherein said compound containing said development restrainer moiety is disposed in a layer between said dyeable stratum and said transparent layer.
2 18. A film unit as defined in claim 13 wherein an opaque dimensionally stable layer is disposed on the outer surface of said negative component.
19. A film unit as defined in claim 11 wherein said compound containing said development restrainer is of the formula:
X represents the atoms necessary to complete a benzene or naphthalene radical;
Y is hydroxyl or a substituent which upon hydrolysis in alkali provides a hyroxyl substituent;
and HET represents the monovalent radical of a heterocyclic ring substituent of a development restrainer of the formula: HSHET, said substituent being ortho or para to said Y substituent.
20. A film unit as defined in claim 19 wherein said development restrainer HSHET is of the mercaptotetrazole or mercaptobenzothiazole series.
21. A film unit as defined in claim 20 wherein said development restrainer is 1phenyl-S-mercaptotetrazole.
22. A film unit as defined in claim 20 wherein said development restrainer is Z-mercaptobenzothiazole.
2. In a film unit for forming a color transfer image viewable without separation as a positive reflection print comprising, in order, an opaque dimensionally stable layer, a layer of a cyan dye developer, a red-sensitive silver halide emulsion layer, a layer of a magenta dye developer, 21 green-sensitive silver halide emulsion layer, a layer of a yellow dye developer, a blue-sensitive silver halide emulsion layer, a dyeable stratum, a spacer layer, a neutralizing layer and a dimensionally stable transparent layer; and means associated with said film unit for applying an aqueous alkaline processing composition containing a white reflecting pigment in a substantially uniform layer between said dyeable stratum and said blue-sensitive silver halide layer;
the improvement which comprises disposing in said dyeable stratum or in a layer between said dyeable stratum and said transparent layer a compound of the formula:
wherein X represents the atoms necessary to complete a benzene or naphthalene radical;
Y is hydroxyl or a substituent which upon hydrolysis in alkali provides a hydroxyl substituent;
and HET represents the monovalent radical of a heterocyclic ring substituent of a development restrainer of the formula: HS-HET, said substituent being ortho or para to said Y substituent.
24. A film unit as defined in claim 23 wherein said compound is disposed in a layer between said dyeable stratum and said transparent layer.
25. A film unit as defined in claim 24 wherein said compound is disposed in said spacer layer.
26. A film unit as defined in claim 23 wherein said development restrainer HS-HETis of the mercaptotetrazole of mercaptobenzothiazole series.
27. A film unit as defined in claim 26 wherein said development restrainer is l-phenyl-S-mercaptotetrazole.
28. A film unit as defined in claim 26 wheerin said development restrainer is Z-mercaptobenzothiazole.
29. In an integral negative-positive film unit for forming color transfer images including a negative component comprising a red-sensitive silver halide layer and an associated cyan image-providing material, a green-sensitive silver halide layer and an associated magenta image-providing material, and a blue-sensitive silver halide layer and an associated yellow image-providing material;
the improvement which comprises including in said negative component a phenol, a naphthol or a protected derivative thereof which upon hydrolysis in alkali will form a phenol or a naphthol, having a development restrainer bonded to a nuclear carbon atom thereof through a methylene substituent in a position ortho or para to the hydroxyl group or the protected hydroxy group.
30. A film unit as defined in claim 29 wherein at least one of said silver halide layers further includes said development restrainer-containing compound.
31. A film unit as defined in claim 29 wherein at least one of said layer containing said image-providing material further includes said development restrainer-containing compound.
32. A film unit as defined in claim 29 wherein said development restrainer-containing component is disposed in a layer overlying said negative component.
33. A film unit as defined in claim 29 including a positive component comprising at least a dyeable stratum disposed in juxtaposition with said negative component.
34. A film unit as defined in claim 33 including means for applying a light-reflecting layer between said dyeable stratum and said neagtive component.
35. A film unit as defined in claim 34 wherein said means comprises a preformed layer of a light-reflecting agent.
36. A film unit as defined in claim 34 wherein said means comprises an aqueous alkaline processing composition including said light-reflecting agent.
37- A film unit as defined in claim 36 wherein said processing composition is confined in a rupturable container positioned with respect to said film unit as to be capable, upon rupturing, of discharging said composition in a substantially uniform layer between said dyeable stratum and said negative component.
38. A process for forming color transfer images comprising the steps of exposing a film unit as defined in claim 1 to form a developable image; and thereafter applying an aqueous alkalin processing composition to develop said image and to form said color transfer image.
39. A process for forming color transfer images comprising the steps of exposing a film unit as defined in claim 11 to form a developable image; and thereafter applying an aqueous alkaline processing composition to develop said image and to form said color transfer image.
40. A process performing color transfer images comprises the steps of exposing a film unit as defined in claim 29 to form a developable image; and thereafter applying an aqueous alkaline processing composition to develop said image and to form said color transfer image.
41. A process for forming images in color comprising the steps of exposing an integral negative-positive film unit including a negative component comprising at least one light-sensitive silver halide layer and an associated dye image-providing material and a positive component containing a dyeable stratum, said film unit also containing a quinone-methide or naphthoquinone-methide precursor containing a development restrainer moiety, which precursor is substantially immobile in said film unit but in the presence of alkali will release said development restrainer moiety as a reagent soluble and diifusible in an alkaline medium and capable of elfectively restraining development of said light-sensitive layer; applying to said exposed film unit an aqueous alkaline processing composition to efiect development of exposed and developable silver halide and to release said development restrainer at some stage after application of said processing composition, said released development restrainer diffusing to said silver halide layer and thereafter effectively restraining further development of exposed and developable silver halide; forming as a function of development an imagewise distribution of mobile and diffusible dye; and transferring said imagewise distribution, at least in part, by diffusion, to said dyeable stratum to impart thereto a color transfer image.
42- A process as defined in claim 41 including the step of disposing a layer of a white light-reflecting pigment between said dyeable stratum and said negative component, whereby said transfer image is viewable, Without separation, as a reflection print.
43. A process as defined in claim 41 including the step of separating said dyeable stratum containing said color 32 image from said film unit after color transfer image formation.
44. A process as defined in claim 41 wherein said dye image-providing material is initially difiusible in said aqueous alkaline composition and said imagewise distribution is formed by selectively rendering said material less dififusible as a function of development.
References Cited UNITED STATES PATENTS 3,364,022 1/ 1968 Barr 963 3,379,529 4/1968 Porter, et al. 96-36 NORMAN G. TORCHIN, Primary *Examiner A. T. SURO PICO, Assistant Examiner US. Cl. X.R.
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|U.S. Classification||430/219, 430/240, 430/957, 430/223|
|International Classification||G03C1/34, G03C1/30, G03C8/24, G03C5/30|
|Cooperative Classification||Y10S430/158, G03C1/34, G03C1/30, G03C5/30, G03C8/243|
|European Classification||G03C1/30, G03C1/34, G03C8/24B, G03C5/30|