US3161506A

US3161506A - Photographic multicolor diffusion transfer process using dye developers

Info

Publication number: US3161506A
Application number: US98292A
Authority: US
Inventors: Richard W Becker
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1961-03-27
Filing date: 1961-03-27
Publication date: 1964-12-15
Anticipated expiration: 1981-12-15
Also published as: CA685877A; FR1320319A; GB1005445A; DE1155333B

Description

United States Patent C New Jersey No Drawing. Filed Mar. 27, 1961, Ser. No, 9%,29'2 1t) Claims. (El. 96-43) This invention relates to the art of photography and more particularly to a multicolor diffusion transfer process in photography and materials adapted to use in the process. p

The application is a continuation-in-part of my US. patent application Serial No. 71,314, filed November 23, 1960.

A diffusion transfer color process has been described in a number of patents, including British Patent 804,971, published November 26, 1958, wherein photographic elements containing silver halide emulsion layers and layers containing diffusible dye developers (dyes having a silver halide developing function) are exposed to record the latent image in the silver halide and then treated with an alkaline processing composition which permeates the emulsion layers and layers containing the dye developers which then develop the latent images to silver images. At the same time oxidation products of the dye developers are formed in situ with the silver images and which are relatively non-diffusing in the colloid vehicle of the layers. The non-diffusing character of the oxidized dye developers is apparently due at least in part to a decrease in solubility in the alkaline processing liquid, and may also be due to a hardening effect of the oxidized developer upon the colloid vehicles of the layers which retards the diffusion of the oxidized dye developers. The residual unoxidized dye developers remaining in the layers in imagewise distribution are transferred by diffusion to a superposed reception element substantially to the exclusion of the silver image and oxidized dye developer to provide a positive dye image.

When an element containing differentially sensitized silver halide emulsion layers is used and subtractively colored dye developers are present in or contiguous to the respective emulsion layers, upon treatment with the processing liquid the dye developers are oxidized and rendered non-diffusing in the developed regions of the layers and the residual dye developer images in the positive regions are transferred by difiusion and in register to the reception element to provide a multicolor reproduction.

it has been observed in this process, that when the dye developer images are transferred to the reception element from the sensitive elements which have been aged for a period of time under adverse conditions or" temperature and humidity, the images tend to have less density than desired and, less density than would be expected from the quantity of dye developer available for transfer. p

I have discovered that greatly increased image density is obtainable if a photographic element is used in the process, comprising a support having superposed thereon a plurality of difierentially light-sensitive silver halide emulsion layers, at least one of said emulsion layers containing a member of the class consisting of hydroxy and amino triazaindenes, hydroxy and amino tetrazaindenes. and hydroxy and amino pentazaindenes, a dye developer being contiguous to the silver halide of each emulsionlayer, said dye developer being a compound which is both a silver halide developing agent and a dye.

The improved image density appears to .result from each dye developer, in its original unoxidized form, difiusing register to the reception artists? imagewise to the receiving layer without being impeded by other reactants or by the reaction products of the process. I

One object of the invention is to provide representative sensitive elements adapted to production of the dye developer images of improved density. Another object is to provide representative processes using the sensitive elements.

In the following description typical sensitive elements will be provided as well as processing solutions and processing variations which yield the most useful dye images, and reception elements adapted to receive the dye images transferred thereto by diffusion. Camera and processing equipment particularly adapted to providing the dye developer images will also be described.

In a typical process for producing the dye developer images a sensitive element comprising a plurality of silver halide emulsion layers diilierentially light-sensitive (sensitive to different regions of the spectrum), having contiguous dye developers which may be subtractively colored with respect to the sensitivity of the corresponding emulsion layer, and preferably contiguous hydroquinone, derivatives, is exposed to a colored subject and processed by wetting with an alkaline processing solution such as one containing hydroxyethyl cellulose as a thickening agent, in contact with the reception layer and preferably in the presence of onium compounds, especially a quaternary ammonium salt, to develop the exposed silver halide in the emulsion layers and thereby render the dye developers non-diffusing in the regions of developmnet, allowing the dye developers in the undeveloped regions to transfer imagewise by diffusion and in register to the reception layer to yield a multicolor dye developer image thereon of improved density.

In a typical process the sensitive element contains superposed gelatin emulsion layers sensitized to the red,

green and blue regions of the spectrum, and at least one emulsion, and preferably all, contain one of the azaindenes; under each emulsion layer is a light-insensitive gelatin layer containing a subtractively colored dye developer (cyan, magenta or yellow colored dye developer), gelatin inter-layers separate the middle emulsion layer and its underlying layer of dye developer from the other two emulsion layers and dye developer layers, and a hydro quinone derivative (described below) is preferably present in one of the layers.

The reception element containing a support and a reception layer thereon (which may contain the onium salt) is positioned so as to receive dye images transferring by diffusion from the sensitive element, with a rupturable container of alkaline processing solution therebetween. Upon rupture of the container as by means of passing the assembly between rollers in a camera so as to distribute the contents uniformly across a predetermined area of the sensitive element, the solution penetrates the emulsion layers with the result that the latent images in the silver halide is developed to silver and the dye developers in the areas including the regions of development. each become immobilized and rendered non-diffusing. The unreacted dye developers of the layers diffuse imagewise in layer and form dye images thereon. In an alternative element the dye developers may be incorporated into the diiferentially sensitized emulsion layers containing the azaindene compounds and the hydroquinone derivative may be present in a layer outermost from the support. This element may likewise be used to provide the dye developer images of improved density.

In the mentioned process using the dye developers it has been discovered thatpartly due to the ineff ciency of the dye developers as silver halide developing agents, the lack of discrimination of the dye developers for the silver halide they should develop, and other factors, when sensitive elements containing a plurality of differently sensitized silver halide emulsion layers and contiguous dye developers for subtractive color reproduction are used in the process the development products of one emulsion tend to effect the development of the other emulsions, the diffusion of a dye developer from a lower layer can be affected, i.e., be hindered, by a dye developer or other substance in an upper layer, the exhaustion of the processing solution by an outer layer may affect development of a lower layer and one layer may not develop to the extent of another layer, and particularly one dye developer may not be immobilized sufiiciently to prevent it from transferring and causing color contamination of a dye image of another color. Also, a given dye developer may develop some grains of silver halide in the wrong emulsion layer with the result that an insufficient amount of that dye developer is available for transfer and the corresponding colors are unsaturated thus a magenta dye developer may develop some grains of red sensitive silver halide and become immobilized thus decreasing the magenta available to produce red colors which then appear unsaturated. When the hydroquinone derivatives described below and the azaindenes are present in the sensitive element these disadvantageous effects are less evident.

It has been mentioned that the onium compounds are preferably used in formation of the dye developer images. These materials are employed particularly with the azain denes also to alleviate the mentioned disadvantageous characteristics of the process such as color contamination. It is believed that the onium compounds interact with the dye developers to form salts thereof and that the improvements in reduced color contamination, color drop off and minimum density obtained by their use are at least due in part to the effect of such salt formation on the solubility and diffusibility of the dye developers. There is evidence that the onium compounds actually temporarily delay the migration of the dye developers so that the initial diffusion rates of the dye developers are reduced, yet more of the dye developers transfers from less exposed areas to increase the density. The beneficial effects of the hydroquinone derivatives include a decrease in color contamination of the dye developer prints which is apparently due to their effecting a more complete and uniform immobilization of the dye developers in the regions of development.

Color contamination usually appears in the prints as a degradation of one or more colors by one or more other colors and may be due to the failure of one or more dye developers to be immobilized sufiieiently to prevent them from transferring from regions where they should have been immobilized. Drop-off appears as a degradation in color quality of the prints apparently caused by one dye developer developing silver halide grains in the wrong emulsion layer, e.g., the magenta dye developer developing some red sensitive silver halide grains with the result that more magenta dye developer is immobilized than should be and the red colors are deficient in magenta and are thus less saturated.

Representative hydroxy and amino triazaindenes, tetrazaindenes and pentazaindenes useful in the emulsions in amounts of the order of from about 1 to 12 grams per mole of silver halide are as follows:

2,4-dihydroxy-6-methyl-1,3 a,7-triazaindene 2,5 -dimethyl-7-hydroxy- 1 ,4,7 a-triazaindene -amino-7-hydroXy-2-methyl-1 ,4,7a-triazaindene 5-carboxy-4-hydroxy-1,3 ,3 a,7-tetrazaindene 1,2-bis( 4-hydroxy-6-methyll ,3,3 a,7-tetrazaindene-5 -yl) ethane 1,2,3 ,4-tetrakis (4-hydroxy-6-methyl- 1 ,3 ,3 21,7-

tetrazaindene-2-yl butane Z-amino-S-carboxy-4-hydroxy-1,3,3a,7-tetrazaindene 4-hydroxy-6-methyl- 1,3 ,3 a,7-tetrazaindene 4: 4-hydroxy-2-fi-hydroxy-ethyl-6-methyl- 1,3,3 a,7-

tetrazaindene 5 -carbethoxy-4-hydroxy- 1 ,3 ,3 a,7-tetrazaindene 7-hydroxy-1,2,3 ,4,6-pentazaindene 2,4-dihydroxy-6-methyl-1,3 a,7-triazaindene 4hydroxy-2'y-hydroxypropyl-6-methyl-1,3,3 a,7-

tetrazaindene 4-hydroxy-2 (4-pyridyl) -6-methyll ,3 ,3 a,7-tetrazaindene 4-hydroxy-6-methyl-1,2,3 ,3 a,7-pentazaindene 5-amino-2- (p-carboxyphenyl) -7-hydroxy-1,3 ,4,6-

pentazaindene Other useful azaindenes are disclosed by the following references:

Allen et al. U.S. Patent 2,735,769, February 21, 1956 Allen et al. U.S. Patent 2,743,181, April 24, 1956 Tinker et al. U.S. Patent 2,835,581, May 20, 1958 Reynolds U.S. Patent 2,756,147, July 24, 1956 Carroll et al. U.S. Patent 2,743,180, April 24, 1956 Zeitschrift fiir Wiss. Phot. 47, 2-28 (1952) Carroll et al. U.S. Patent 2,716,062, August 23, 1955 Allen et al. U.S. Patent 2,772,164, November 27, 1956 Allen et al. U.S. Patent 2,713,541, July 16, 1955 Tinker U.S. Patent 2,852,375, September 16, 1958 Carroll U.S. Patent 2,743,180, April 24, 1956 Fry U.S. Patent 2,5 66,65 89, September 4, 1951 Heimbach et al. U.S. Patent 2,444,605-7, July 6, 1948 Heimbach et al. U.S. Patent 2,449,225-6, September 14,

Onium compounds have been used in the photographic art for quite some time. For example, U.S. Patent No. 2,648,604 discloses the use of non-surface-active quaternary ammonium compounds as development accelerators and U.S. Patents Nos. 2,271,623, 2,271,622 and 2,275,727 disclose the use of quaternary ammonium, quaternary phosphonium and tertiary sulfonium compounds as sensitizers for silver halide emulsions. Notwithstanding the fact that such onium compounds have been previously used as sensitizers and as development accelerators, the mentioned results obtained by using onium compounds in conjunction with the dye developers in the diffusion-transfer processes of this invention are worthy of note. In the processes disclosed in the above-mentioned U.S. patents, there is an increase in silver density in the negative due to the use of the onium compounds; however, the increase in density in such processes takes place in the exposed areas of the negative and is attributable to the above-mentioned ability of the onium compounds to sensitize an emulsion or to accelerate development. In the present processes, when an increase in density is obtained in presence of the onium and azaindene compounds it takes place in the positive image and is primarily the result of increased transfer of the dye developer from unexposed areas of the negative. The fact that the onium and azaindene compounds would coact with dye developers to increase the transfer of such dye developers from unexposed areas of the negative in no way was expected from the prior use made of such compounds as sensitizers or development accelerators.

The fact that the onium compounds would also act, especially in the presence of the hydroquinone derivatives, to inhibit transfer of the oxidized dye developers from the exposed areas and thus improve the highlights, was similarly unexpected. This improvement in highlights is believed to be due to tire ability of the onium compounds to control, especially in the exposed areas, the diffusibility of such dye developers.

Especially useful results have been obtained through the use of quaternary ammonium compounds. As is known, quaternary ammonium compounds are organic compounds containing a pentavalent nitrogen atom. Generally, they can be considered as derivatives of ammonium compounds wherein the four valcnces usually occupied by the hydrogen atoms are occupied by organic radicals. Generally, the organic radicals are joined directly to the pentamay be made of those represented by the following formul ae a .z. V

wherein each R is an organic radical, Y is an anion, e.g., hydroxy, bromide, chloride, toluene sulfonate, etc., and Z represents the atoms necessary to complete a heterocyclic ring. As examples of compounds Within Formulae l, 2 and 3, mention may be made of tetraethyiammonium bromide, N-ethylpyridinium bromide, N,N,-diethylpiperdinium bromide, ethylene-bis-pyridinium bromide, l-eth ylpyridinium bromide, l-phenethyl-3-picolinium bromide, tetraalkylammonium salts, cetyltrimethylammonium bromide, polyalkylene oxide bis-quaternary ammonium salts such as polyethylene oxide bis-pyridinium perchlorate, the heterocyclic quaternary ammonium salts mentioned which form the methylene bases including 3-methyl-2-ethylisoquinolinium bromide, 3-methylisoquinolinium methyl-ptoluenesulfonate, 1-ethyl-2-1nethyl-3-phenethylbenzimidazolium bromide, 5,6-dichloro-1-ethyl-2-methyl-3-(Z-sulfobutyl)-benzimidazolium betaine and the pyridinium salts below.

The tertiary sulfonium and, quaternary phosphonium compounds may be represented by the formulae:

and

fonium bromide, tetraethylphosphonium bromide, dimeth- .ylsulfonium ptoluene sultonate, dodecyldimethylsulfonium p-toluene sulfonate, decyldimethylsulfonium p-toluene sultonate and ethylene-bis-oxymethyitriethylphosphonium bromide. V v

The onium compounds'may be used as the hydroxide or as the salt.. When the onium compounds are used as the salt, the anion may be a derivative of any acid. However, it should be noted that when the anion is iodide, such iodide may have deleterious effects on the emulsion and suitable precautions should be taken. Especially good results were obtained when theonium compounds were employed as the bromide. v

The particularly efficaciousaheterocyclic quaternary ammonium compounds which form the methylene bases 6 difiusible in alkaline solution have the generalformula I Ri 'r =onon ,.=o onm' wherein D represents the non-metallic atoms necessary to complete the heterocyclic nucleus of the quaternary ammonium compound containing 1 or more of the reactive methyl groups -CH R' in one or more of the nuclear positions, the other nuclear positions being substituted or not, such as quaternary salts of the pyridine, quinoline, benzoquinoline, benzoxazole, benzoselenazole, thiaz'ole, benzothiazole, naphthothiazole, benzimidazole, isoquinoline series, etc., it is 0 or 1, R is an alkyl group, an

aryl or aralkyl group of the benzene series, or substituted alkyl, aryl or aralkyl groups of the benzene series, the alkyl chains preferably being lower alkyl of from 1 to 4 carbon atoms, R is a hydrogen atom or one of the groups represented by R, and X represents OH or an acid anion such as BI (II-1 or One or more of these quaternary ammonium compounds can be used alone or in combination with the onium compounds having the Formulae l, 2, 3, 4 and 5 above,

and are advanta eousl emplo ed in either the rocessing 7 density and contrast.

The onium compounds can be used in varying amounts depending upon the particular compound. When used in the alkaline processing solution, useful results can be obtained with from about 0.2 to 15% of onium compound. In some cases about 0.2 to 3% is best. 'Similarly, the amount used in the sensitive element and receiving sheet will vary with the oniurn compound selected.

The quaternary ammonium compounds comprising a preferred embodiment of the invention are pyridinium salts which form the diliusible methylene bases and which have the above Formula 6, the pyridinium nucleus being substituted with from 1 to 3 active methyl groups -CH R' present in at least one of the 2, 4 or 6 positions, e.g., a lower alkyl group such as methyl, ethyl, propyl or substituted lower alkyl groups such as hydroxyalkyl, e.g., hydroxyethyl, which alkyl groups act as methylene base precursors. Positions 3 and 5 may or may not be substituted with, e.g., halogen, lower alkyl and haloalkyl groups such as chlorine, methyl, ethyl, propylor chloroethyl groups. s

Typical salts having'the above Formula 6 are as follows:

l-benzyl-Z-picolinium bromide Z-ethyl-l-phenethylpyridiniurn bromide toluenesulfonate I l-[3-(N pyridinium bromide)propyl] 2 picoliniu'm pi -CH3 N PTS 4H8S a a-Picoline-fi-naphtholymethylbromide CHgOC- 1-,8-phenylcarbamoyloxyethyl-Z-picolinium bromide l-methyl-Z-picolinium PTS 1-phenethyl-2,4,6-trimethylpyridinium bromide 1-phenethyl-4-n-propylpyridinium bromide 4- -hydroxypropyl-1-phenethylpyridinum bromide and l-n-heptyl-Z-picoliniurn bromide A number of pyridinium salts having the above general formula do not form methylene bases sufficiently diffusible in alkaline solution to be of practical use in the process, e.g.,

l-n-decyl-Z-picolinium bromide 1,2-dibenzyl pyridinium bromide 6-amino-l-phenethyl-2-picolinium bromide 2-amino-l-phenethyl-4-picolinium bromide 2-benzyl-1-phenethyl pyridinium bromide 4-benzyl-1-phenethyl pyridinium bromide The following which do not form methylene bases in alkali solutions are also less useful.

l-phenethyl pyridinium bromide l-ethyl pyridinium bromide 1-phenethyl-3-picolinium bromide l-n-nonylpyridinium PTS The hydroquinones which have the requisite properties are substantially colorless, substantially water-insoluble, and soluble and diflusible in alkaline solution through organic colloid layers such as gelatin and are exemplified by the following Bromohydroquinone 3,6-dichlorohydroquinone Z-dimethylaminomethyltoluhydroquinone 2-cyclohexylhydroquinone Sec. butylhydroquinone 2,5-dichlorohydroquinone 2,S-diisopropylhydroquinone 2,5-diiodohydroquinone 3-chlorotoluhydroquinone T etrachlorohydroquinone 2,5-diphenylhydroquinone 2,S-diresorcylhydroquinone 2,5-dioctylhydroquinone Dodecylhydroquinone The useful hydroquinone derivatives are particularly distinguished from the dye developers containing hydroquinonyl moieties mentioned hereinafter, in being substantially colorless and therefore do not impart any color to the print.

The processes of the invention are thus carried out with the silver halide emulsions and dye developers preferably in contiguity with both the quaternary ammonium salts and the hydroquinone derivatives. That is, the quaternary salt may be present in either or both the alkaline processing fluid, the reception sheet, less desirably in the sensitive element, and the hydroquinone derivative in any of the layers of sensitive element such as an overcoating layer, emulsion layer, dye developer layer, and interlaycr, or in the reception sheet. Thus, the reception sheet or reception layer may be composed of a mordant for the dye developers such as mentioned below, e.g., poly-4-vinylpyridine and in addition may contain at least one of the hydroquinone derivatives above. Similarly, the reception layer or sheet may contain the combination of a mordant for the dye developers, at least one of the hydroquinone derivatives and at least one of the onium compounds mentioned, particularly the heterocyclic quaternary ammonium compounds forming the methylene bases. For some purposes the hydroquinone derivatives may be present in the processing fluid containing the hydroxyethyl cellulose; however, in the present invention use in the fluid is much less desirable since the hydroquinone derivatives are unstable in such solutions and readily undergo oxidation accompanied by discoloration of the prints, unless prepared and stored in absence of air or other precautions are taken to prevent oxidation.

The hydroquinone derivatives used as described, are preferably incorporated into emulsion layers, overcoating, interlaycrs or other layers, as dispersions in the hydrophilic organic colloid vehicle of the layer. The hydroquinone derivatives may be dissolved in alkaline solution and precipitated into aqueous gelatin solutions by raising the acidity of the solution. However, this is a less desirable procedure because of the instability of the compounds in alkaline solution. The hydroquinone derivatives may be dissolved in a solvent, such as a lower alcohol, and precipitated into aqueous gelatin solutions for coating on the sensitive element. They may be added to gelatin solutions which are ball-milled to reduce the crystal size. However, the hydroquinones are preferably dissolved in a low molecular weight water-insoluble organic crystalloidal solvent permeable to the alkaline processing solutions and having a boiling point above about 175 C. such as dibutyl phthalate and added to an aqueous gelatin solution which is passed through a colloid mill until the desired degree of subdivision has been attained. An auxiliary organic solvent can also be used such as one having a solubility in water greater than that of the crystalloidal solvent, of the order of at leastabout 2 parts per parts of water. Thus the auxiliary organic solvent can be washed from a chilled gelatin dispersion in the presenceof the other solvent. The auxiliary solvent may be one having a boiling point at least i on Q about 25 C. lower than the crystalloidal solvent in order that it can be removed by volatilization during the drying of a coating'to leave the hydroquinone derivative dispersed in only the crystalloidal solvent. As a result, the hydroquinone derivatives are quickly and uniformly dissolved by the alkaline processing composition and transported throughout the sensitive element to produce more uniform development than when the hydroquinone derivatives are incorporated into the element by other means.

The hydroquinone derivatives may be used in one or more layers of the sensitive element in quantities of the order of from. about to 100 mgs. or more per square foot. However, the quantity used depends in part upon the amount of silver halide, the layer in which it is contained, the amount of dye developer and the amount of pyridinium salt in the sensitive element or processing solution of reception element. In some instances it may be desirable to form a complex of the hydroquinone derivativcs by reaction with sulfur dioxide in a well-known manner and to incorporate the complex in the overcoating layer, outer emulsion or other layer of the sensitive element. These hydroquinone-sulfur dioxide complexes tend to be more stable than the hydroquinone derivatives themselves.

The dye developers whichare used in the emulsion layers or in layers adjacent to the emulsion layers are compounds which are both a silver halide developing agent and a dye. They are characterized by being relatively non-ditlusible in the colloid layers at a neutral pH but diffusible in the layers in the presence of the alkaline processing solutions. For the most part the dye developers are insoluble in water per se, which property usuallynecessitates the use of organic solvents to incorporate the dye developers into the organic colloid layers or" the sensitive elements. Otherwise, the solubility of the dye developers is not particularly important and so long as the dye developers are capable of being immobilized in the layers in the presence of the alkaline processing solution and they are transferrable to the reception element, they are useful in the process of the invention. The dye developers are particularly characterized by containing both a chromophore moiety and at least one moiety such as a hydroquinonyl radical having .a silver halide developing agent function and which radical emulsions.

Representative dye developers are disclosed in Australian Patent 220,279 accepted December 17, 1958, and

German Patent 1,036,640, August 14, 1958, for example,

' 4-- [p- 2',5 '-dihydroxyphenyl -phenylazo] -5-acet aniidol-naphthol.

4- [p- 2,5'-dihydroxyphenethyl) :phenylazo1-5-henzamido-l-naphthol.

1-phenyl-3-methyl-4- [p-(2',5 dihydroxyphenethyl) phenylazo1-5-pyrazolone. 1 V

2- [p- 2,5 -dihydroxyphenethyl) -phenylazo] l-acetamido-l-naphthol. p

2 [p- (2f,5-dihydroxyphenethyl -phenylazo] -4-arninol -naphthol. I

developer) it? 7 2- p- 2,5'- dihydroxyphenethyl) -phenylazo] 4-methoxyl-naphthol. 2-[p-(2,5-dihydroxyphenethyl)-phenylazo1-4-etl1oxyl-naphthol. 2- p- 2,5 '-dihydroxyphenethyl) -phenylazo] -4-npropoXy-l-naphthol ((Iompound II).

(yellow dye developer) l-acetoxy-Z- [p- B-hydroquinonylethyl) -phenylazo] -4- methoxy naphthalene.

l-isobutoxy-Z- [p- (,B-hydroquinonylethy1) -phenylazo] l-naphthol.

1-acetoxy-2- p- B-hydroquinonylethyl) -phenylazo] -4- propoxy naphthalene.

2- [p- (2,5'-dihydroXy-4-methylphenethyl phenylazo] 4-pro-poxyl-naphthol.

l-phenyl3 [N- fl-ethylhexyl -carboxamide] -4- [p (,8'-

hydroquinonylethyl) -phenylazo -5-pyrazolone.

l-phenyl-3- (N-n-heptyl carooXamidol- [p- (,B-hydroquinonyiethyl) phenylazo] -5-pyrazolone.

l- (o-carboxyphenyl) -3 -phenyl-4- p- 2,5 -trifiuoroacetoXy-fi-phenylethyl) phenylazo] -5-hydroxy pyrazolone lactone.

1- o-carboxyphenyl) -3 -N-phenylcarboxarnide-4- [p- (B'- hydroquinonylethyl -phenylazo] -5 -hydroxypyrazole lactone.

British Patents 804,971, November 26, 1958, and 804373, November 26, 1958, describe other dye developers, for example: Y

. 1,4bis- 2,5- dihydroxyanilino) -anthraquinone,

(magenta dye l,S-his(2,5'-dihydroxyanilino)-4,8-dihydroXy-anthraquinone, V I

quinone,

OH i 1TlHOI-IOH l l I 0H (dd1.).

cyan ye QVBO 61 H H p r Nrroir orn 1,4-bis[l3- (2',5 -dihydroxyphenyl) isopropylamino1anthraquinone,

1,4-[- 2',5'-dihydroxyphenyl) ethylamino] anthraquinone,

1-chloro-4- fi- 2,5 -dihydroxyphenyl -ethylamino]anthraquinone,

N-monobenzoyl-1,4-bis-[fi-(3 ,4'-dihydroxyphenyl ethylamino] anthraquinone,

N-monobenzoyl-1,4-bis [,8-(2',5'-dihydroxyphenyl) -ethylamino] anthraquinone,

5 ,8-dihydroxy-1 ,4-bis fi-hydroquinonyl-e-methyl) ethylamino] anthraquinone (Compound I) 1,4-bis[ fl-hydroquinonyl-ot-ethyl ethylamino] -anthraquinone,

5hydroxy-1,4-bis[ B-hydroquinonyl-a-mcthyl -ethylamino -anthraquinone,

lli-hydroxy-ot-ethyl-ethylamino -4- (fi-hydroquinonyla-methyl)-ethylamino-anthraquinone, and

1- (butanol-2-amino -5 ,8-dihydroxy-4-hydroquinonylisopropylarnino-anthraquinone.

Additional dye developers useful in the invention are disclosed by Belgian Patents 554,935 and 568,344, British Patents 884,972, 804,974 and 804,975, French Patent 1,168,292, Canadian Patents 579,038 and 577,021.

Leuco compounds may be used similarly, e.g., l-phenyl- 3 methyl 4 (2-methyl-4'-diethylamino)anilino-S-pyrazolone, which do not exert a filtering action on underlying emulsion layers and which are immobilized in the developed regions, diffuse imagewise from undeveloped areas to the reception layer and are oxidized to colored images therein.

The dye developers are employed in the sensitive elements contiguous to the silver halide of the emulsion layers, that is, they may present in one or more of the emulsion layers or preferably in a hydrophilic organic colloid layer immediately next to and particularly under the silver halide emulsion layer. Especially good results are obtained when the dye developers are positioned so as to be present in the layer immediately under the emulsion layer, the sensitivity of which is complementary to the color of the dye developer. It appears less desirable to locate the dye developer in a layer positioned above the corresponding layer of silver halide emulsion. The contiguity of the dye developer with respect to the silver halide can take the form of a mixed packet system wherein the dye developer may be present in a matrix surrounding a particle or globule containing silver halide grains.

In multilayer sensitive elements the order of arrangement of the differentially sensitized silver halide emulsion layers on the support can be such that the red sensitive layer is on the support, the blue sensitive layer outermost and the green sensitive layer in between, or the arrangement can be reversed so as to have the blue-sensitive emulsion layer on the support and the red sensitive emulsion layer outermost. In such arrangements of layers the sensitivities of the silver halide emulsions should be adjusted so as to prevent recording unwanted blue light images in the emulsions primarily sensitive to the red and green regions of the spectrum, e.g., a silver bromide emulsion can be used for the blue sensitive emulsion and silver chloride emulsions for the other layers. in instances of this type it may be desirable to utilize the leuco compounds mentioned above in place of one or more of the dye-developers which, since they may have some blue absorption, might tend to exert an undue filtering action on the blue sensitive bottom emulsion layer.

The hydrophilic organic colloid vehicle of the emulsion layers, overcoating layers, of the dye developer layers and of interlayers can be varied somewhat, for example, gelatin, gelatin derivatives such as dibasic acid esters of gelatin, polyvinyl alcohol and cellulose acetate hydrogen phthalate, or mixtures of the hydrophilic organic colloid vehicles, may be used. However, the best and most consistent results, and consequently prints of the highest quality, are obtained when gelatin is used as a colloid vehicle throughout all layers of the sensitive element. In fact, when gelatin interlayers are used they should be at least about of the measured thickness of the yellow dye developer layer and contain at least about two times the amount of gelatin present in that layer in order to prevent undue wandering of the dye developer and development products from layer to layer. Other hydrophilic organic colloids yield less desirable results when used in the layers. For example, when some of the layers contain gelatin vehicle and interlayers of polyvinyl alcohol or cellulose acetate hydrogen phthalate are used, the layers tend to strip apart particularly when dry. Also, when gelatin is used throughout more uniform transfer of the alkaline processing solution and hydroquinone derivative through the layers is obtained and the dye developers comprising the final print transfer more readily to the reception layer.

The processing solution used to initiate development of the exposed sensitive elements containing the dye developers and hydroquinone derivatives, and which may contain the quaternary ammonium salt, should be strongly alkaline to accelerate the development activity of the dye developer as much as possible. Alkali metal hydroxides such as sodium hydroxide or alkaline salts such as sodium carbonate are advantageously used in the activator composition for this purpose. However, quaternary ammonium hydroxides or volatile amines such as diethyl amine, which have the advantage of being volatilized from the prints and therefore leave no residue of alkali thereon which might tend to decompose the dye images, may also be used. As mentioned previously, since the hydroquinone derivatives may tend to be unstable in the strongly alkaline activator, they are preferably not incorporated in the processing solution although when the pyridinium salts are present, results are obtained which are satisfactory in other respects. The results most desired are obtained when the hydroquinone derivative is present in the layers of the sensitive elements. Therefore, no silver halide developing agent need be present in the processing solution. The alkaline processing solution may be replaced with water or a water solution of pH 7.5 or less if the contiguous receiving sheet contains an alkali or an alkali releasing material. If the water or water solution is integumented and incorporated in the light sensitive element or in the mordanted receiving sheet it may be released by suitable rneans such as by pressure or by heat. I

The sensitive elements of the invention are, of course, adapted to use in a camera for taking pictures in the usual manner. Moreover, the development of the sensitive elements, i.e., the treatment with an alkaline activator solution to initiate development, can also be carried out in the camera by use of rupturable containers of processing solution or other means may be used to spread the processing solution uniformly across the picture area of one or more consecutively exposed images and in contact with the reception layer. For this purpose, it may be desirable to use a processing solution containing in addition to strong alkali a thickening agent such as carboxymethyl cellulose or highiscosity hydroxyethyl cellulose in suitable quantity to obtain the desired viscosity. Other means can be used such as spraying, dipping, roller coating, etc. to apply the processing solution to the exposed element and to initiate its development.

Thus, several consecutive exposures on a strip of the sensitive element can all be wetted with the alkaline processing solution and the dye developer images transferred to a single strip of reception material to provide several color prints in a single transfer operation.

One method for obtaining the color prints from a strip of the sensitive element containing a series of, for example, three or four consecutive exposures, is to apply the viscous processing solution from a releasably confining or rupturable container in a compartment such as a magazine, integral with a camera in the manner described below, to cause each of the exposed areas to be wetted with the processing composition at approximately the same time in contact with a strip of reception material and the corresponding multicolor images to transfer thereto to provide a series of colored images on a single strip or" the reception material.

A different means for providing prints from the sensitive element containing a series of image exposures such as three or four consecutive exposures, is to expose the element to several subjects in a conventional camera not necessarily adapted to use of rupturable containers of the processing composition, and withdrawing the exposed element from the camera in a convenient manner so as to prevent fogging of the emulsions. Thus, the element can be exposed and Wound upon itself on a spool in an ordinary roll-film type of camera so as to exclude light, by use of a lightdmpervious covering such as'black paper, a cassette or a magazine. The element can then be withdrawn from the camera and placed in a convenient portable light-impervious enclosure of small dimension for application of the viscous processing fluid to the element from, for example, a single rupturable container or several rupturable containers corresponding to the number of exposures recorded on the strip of sensitive element or by application of the fluid to the element by means of a wick, roller or similar applicator, so that each of the exposed areas is wetted. As a result and subtractively colored dye developers contiguous to the silver halide of each emulsion layer, is wetted with the'alkaline fluid in the presence of the onium salts, and

preferably in the presence of the hydroquinone'derivatives, and brought into contact with the reception layer for a time sutficient for adequate development of each image, to cause the silver halide in the several exposed areas of each emulsion layer to develop and thereby render the corresponding dye developers immobile and the dye developers in the unexposed portions of each of the several exposed areas to transfer to the reception layer and provide a series of prints thereon composed of the dye developers.

Camera apparatus of the type useful for exposing and processing the sensitive elements of the invention have been described, for example, in U.S. Patent 2,435,717. Such cameras permit successive exposure of individual frames of the photo-sensitive element from the emulsion side as well as processing of an exposed frame by bringing the exposed portion of the photo-sensitive element in superposed relation with a portion of the print receiving element while drawingthese portions of the filmassembly between a pair of pressure rollers which rupture the container associated therewith andspread the processing liquid between and in contact with the photosensitive element and the corresponding registered area of the print receiving element. The photosensitive element and print receiving element during the spread;

ing of the container contents become formed into a combination wherein the photosensitive element and print receiving element are so superposed with respect to each other that the spread liquid has access to both of the elements. This superposed relationship between the photosensitive and print r'eceiving'elemen'ts is maintained until the elements are "stripped aparttOllowing the deposit on the print receiving element of thedye forming the final color image. 7 i r i r The reception layers togwhich the dye developers are transferred imagewise to obtain the multicolor images may .be composed of various materials suchnas linear polyamides, proteins-such as gelatin, polyvinyl pyrrolidohe,

poly-4-vinyl pyridine, polyvinyl alcohol, polyvinyl salicylal and methyl cellulose. These reception layers are coated ona suitable support such as'a paper support, apolyethylene coated paper support,1a'transparent film or a white pigl 4 merited cellulose ester support to obtain a print or transparency as the case may be.

In the process of the invention it may be desirable to employ an antifoggant in the sensitive element, in the alkaline processing solution or the reception element or in each, and a development arresting compound in the reception element. When development arresting compounds are present in the reception element rather than in the sensitive element or solution they do not become etfective until dissolved by the processing solution and have migrated to the sensitive element under development. As a result, the latent image is allowed to develop very rapidly and the development arresting effect is delayed until the development of the exposed areas has essentially reached completion before development is appreciably arrested. This results in the prevention or" development in the unexposed areas and increases the amount of dye developer transferring. Additional improvement is obtained when the development arrestor is present in the reception layer and the mentioned quaternary salts are present in either the processing solution or the reception layer, or both. Suitable development arrestors are heterocyclic mercaptans such as mercaptotetrazoles and mercaptobenzothiazoles, e.g., l-phenyl S-mercaptotetrazole, 2-n1ercaptobenzothiazole, etc. usually considered to be anti-foggants for silver halide do not arrest development as desired.

In a further variation of the invention a small amount of a silver halide solvent such as alkali metal or ammonium thiosulfate or thiocyanate may be incorporated into the alkaline processing composition or the receiving layer, or both, with the result that the effective protographic speed of the process is increased. However, the effect of the silver salide solvent becomes most apparent when either or both the mentioned hydroquinones and quaternary salts are present. Ordinarily the amount of silver halide solvent used is not sufiicient to cause any appreciable amount of silver halide to be dissolved from the unexposed and undeveloped areas of the sensitive element and to be transferred to the reception layer.

The invention contemplates sensitive elements wherein the emulsion layers, contiguous hydroquinone derivatives and dye developer layers are integral with the support,

e.g., coated on a support capable of receiving the dye de- 7 one of the layers the fluid may merely be an aqueous solution supplied to release the alkali.

The silver halide emulsions of the sensitive elements of the invention include well-known silver halides and mixtures thereof, for example, silver bromide, silver bromo iodide or silver chlorobromide emulsions.

The emulsion addenda described in the Whitmore et al.

,US. patent application Serial No. 734,141, filed May 8,

1958, and French Patent 1,205,755, August 17, 1959, including the noble metal salts, stannous salts, polyamines, optical sensitizing dyes, mercury compounds, quaternary ammonium salt and polyethylene glycol speeddncreasing compounds, plasticizers, hardeners, coating aids and colloid vehicles disclosed therein may be used advantageously in the silver halide emulsion layers and adjacent layers of the sensitive elements of the'present invention;

The use of the representative sensitive elements containing the azaindene compounds in the process of thein- V vention is shown in the following representative example."

, 1 EXAMBLE A sensitive element was prepared by coating a subbed film support with suitably hardened gelatin layers. as follows z' An'aqueou's gelatin solution containing the cyandye Many compounds 2 5 developer (Compound I above) dissolved in a mixture of N-n-butylacetanilide, 4-methyl cyclohexanone and dispersing agent Alkanol B, and the mixture passed through a colloid mill several times, coated and dried so as to volatilize the 4-methyl cyclohexanone.

A gelatino silver bromoiodide emulsion layer sensitized to the red region of the spectrum and containing 4 grams of 4-hydroxy-6-methyl-l,3,3a,7-tetrazaindene per mole of silver halide was coated upon the cyan dye developer layer.

A gelatin interlayer was then coated.

An aqueous gelatin solution containing the magenta dye developer (Compound II above) dissolved in a mixture of cyclohexanone, N-n-butylacetanilide and Alkanol B, and the mixture passed through a colloid mill several times, coated on the interlayer and dried to volatilize the cyclohexanone.

A green sensitive emulsion also containing 4 grams of the above azaindene compound per mole of silver halide was coated upon the magenta layer.

A second gelatin interlayer was applied.

An aqueous gelatin solution containing the yellow dye developer (Compound 111 above) dissolved in a mixture of ditetrahydrofurfuryl adipate, ethylene glycol monobenzyl ether, and Alkanol B, and the mixture passed through a colloid mill several times, the resulting dispersion chilled to set it, washed to remove ethylene glycol monobenzyl ether followed by coating upon the second interlayer and drying.

A blue sensitive bromoiodide emulsion containing the above amount of azaindene compound was coated on the yellow dye developer layer.

The following was prepared:

Hydroquinone Derviative Dispersion D-l Heat to 40 C.

Part A was slowly added to Part B with the aid of mechanical agitation. The solution obtained was then passed through a Manton-Gaulin laboratory colloid mill five times. The colloid mill was then rinsed and the dispersion was adjusted to a weight of 3775 g., chill set and stored in a refrigerator.

A coating composition was prepared as follows:

PART I Dispersion D-l g 3775 Water rnl 2225 Heat to 40 C.

PART II gelatin solution g 3180 Water "ml" 12,000 Mucochloric acid (2.7% aqueous solution) ml 515 Heat to 40 C. adjust pH to 5.5.

Parts I and II were then combined and diluted with water to 22,700 mi. This solution was coated on the blue sensitive layer to yield afcoverage ofapproximately 120 mg. of gelatin per sq. ft; and 40 mgjper sq. ft. of 4'- methylphenylhydr'oquinone.

A sample of the resultant freshly coated film designated N0. 4894 was exposed under a step tablet through red,-

green and blue filters, and Wetted with the following Activator in contact with the Receiving Sheet below With the result that the cyan, magenta and yellow dye developer images transferred from the undeveloped regions to the receiving sheet. After about two minutes the receiving sheet containing the dye developer images was removed and density values of the dye images were recorded using red, green and blue filters in the usual manner.

Activator:

3.5% HEC (Hercules type 250, high viscosity);

4.5% NaOH; 2.0% benzotriazole, 2.0% l-phenethyl-Z-picolinium bromide.

Receiving sheet: A white pigmented cellulose ester support carrying a gelatin layer containing a mixture of poly- 4-vinyl pyridine mordant and l-phenyl-S-mercapto tetrazole.

Additional samples of film No. 4894 were incubated for 7 days at 120 F. and 50% relative, exposed and processed as above to yield dye developer images having good density.

A control film No. 4893 was prepared in the same manner as 4894 except omitting the azaindene compound f-rom the emulsions and samples thereof were processed as described both when fresh and after incubation for 7 days as above.

The relative densities of the images of film 4893 and 4894 before and after incubation are shown in the following table:

*Contains the azaindene compound.

From these data it will be apparent that the film 4894 containing the azaindene compound of the invention produced cyan, magenta and yellow images of substantially the same density before and after incubation whereas the 7 control film 4893 containing no azaindene compound produced cyan, magenta and yellow dye images having appreciably lower densities after incubation.

In the manner of the above example, in two similar elements containing green-sensitive gelatino silver bromoiodide emulsion layers and underlying dye developer layers, 4 grams of 4-hydroxy-6-methyl-l,2,3,3a,7-pentazaindene per mole of silver halide and 4 grams of 2, dihydroxy-6-methyl-1,3a,7-triazaindene per mole of silver halide, respectively, were added to the emulsions. After incubation of the two elements under the above conditions, the prints made therefrom sustained less loss of density than the control element containing no azaindene compound.

The other triazaindenes, tetrazaindenes and pentazaindenes can be used in the emulsion layers in the same manner. It may be desirable in some instances to use different amounts and different types of the azaindenes in the respective emulsion layers of the multilayer film.

In coating films in the manner described above, the coating uniformity of the emulsion layers is greatly increased if an anionic surfactant such as an alkyl aryl sulfonate, e.g., Alkanol B (sodium triisopropyl naphthalene sulfonate) is added to the dye developer layers, and the silver halide emulsions coated thereon contain a cationic surfactant such as lauryl-pyridinium-p-toluene sulionate. The unique efifectof the azaindenes may result from a coaction with the dye developers or other compopent of the system.

, WhatIclaimis: V p

1. A color photographic diffusion transfer process 17 which comprises exposing to a subject a photographic element comprising a support having superposed thereon a plurality of light-sensitive hydrophilic organic colloidsilver halide emulsion layers optically sensitized to dilferent regions of the spectrum, at least one of said emulsion layers containing an azaindene selected from the group consisting of a hydroxy triazaindene, an amino triazaindene, a hydroxy tetrazaindene, an amino tetrazaindene, a hydroxy pentazaindene and an amino pentazaindene, and a dye developer that is both a silver halide developing agent and .a dye contiguous to the silver halide of each of said emulsion layers, pressing said photographic element into superposed contact with a'mordanted reception layer with a layer of alkaline solution therebetween and thereby developing silver halide in regions of exposure and rendering the said dye developers nondifiusible in regions of exposure and development, and allowing the said dye'developers in unexposed regions to transfer imagewise by diffusion and in register to said reception layer.

2. A color photographic diffusion transfer process which comprises exposing to a subject a photographic element comprising a support with superposed red, green and blue light-sensitive gelatino-silver halide emulsion layers, about 1 to 12 grams per mole of silver halide of an azaindene selected from the group consisting of a hydroxy triazaindene, an amino triazaindene, a hydroxy tetrazaindene, an amino tetrazaindene, a hydroxy pentazaindene and an amino pentazaindene incorporated in at least one of said emulsion layers, and a dye developer that is both a silver halide developing agent and a dye in a layer contiguous to each of said emulsion layers that bears a complementary relationship to the color of the spectral sensitivity of the respective silver halide emulsion layers contiguous thereto, pressing said photographic el ment into superposed contact with a mordanated reception layer with an alkaline solution therebetween and thereby developing silver halide in regions of exposure and rendering said dye developers nondiffusible in regions 'of exposure and development, and allowing said dye developers in unexposed regions to transfer imagewise by diitusion and in register to said'reception layer.

3. A color photographic diffusion transfer process which comprises exposing to a subject a photographic element comprising a support with superposed red, green and blue light-sensitive gelatino-silver halide emulsion layers, about 1 to 12 grams per mole of silver halide of 4-hydroxy-6-methyl-1,2,3,3a,7-pentazaindene incorporated in at least one of said emulsion layers, and a dye developer that is both a silver halide developing agent and a dye in a layer contiguous to each of said emulsion layers that bears a complementary relationship to the color of the spectral sensitivity of the respective silver halide emulsion layers contiguous thereto, pressing said photographic element into superposed contact with a mordanted reception layer with an alkaline solution therebetween and thereby developing silver halide in regions of exposure and rendering said dye developers nondiffusible in regions of exposure and development, and allowing said dye developers in unexposed regions to transfer imagewise by diifusion and in register to said reception layer.

4. A color photographic diffusion transfer process which comprises exposing to a subject a photographic element comprising a support with superposed red, green and blue light-sensitive gelatino-silver halide emulsion layers,

about 1 to 12 grams per mole of silver halide of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene incorporated in at least one of said emulsion layers, and a dye developer that is both a silver halide developing agent and a dye in a layer contiguous to each of said emulsion layers that bears a complementary relationship to the color of 18 thereby developing silver halide in regions of exposure and rendering said dye developers nondiifusible in regions of exposure and development, and allowing said dye developers in unexposed regions to transfer imagewise by difiusion and in register to said reception layer.

5 A color photographic diifusion transfer process which comprisesexposing to a subject a photographic element comprising a support with superposed red, green and blue light-sensitive gelatino-silver halide emulsion layers, about 1 to 12 grams per mole of silver halide of 2,4-dihydroxy-6-methyl-l,3a,7-triazaindene incorporated in at least one of said emulsion layers, and a dye developer that is both a silver halide developing agent and a dye in a layer contiguous to each of said emulsion layers that bears a complementary relationship to the color of the spectral sensitivity of the respective silver halide emulsion layers contiguous thereto, pressing said photographic element into superposed contact with a mordanted reception layer with an alkaline solution there- .between and thereby developing silver halide in regions of exposure and rendering said dye developers nondiffusible in regions of exposure and development, and allowing said dye developers in unexposed regions to transfer imagewise by diffusion and in register to said reception layer. a

6. A photographic element comprising a supporthaving superposed thereon a plurality of light-sensitive hydrophilic organic colloid-silver halide emulsion layers optically sensitized to different regions of the spectrum, at least one of said emulsion layers containing an azaindene selected from the group consisting of a hydroxy triazaindene, an amino triazaindene, a hydroxy tetrazaindene, an amino tetrazaindene, a hydroxy pentazaindene and an amino tetrazaindeue, and a dye developer that is both a silver halide developing agent and a dye contiguous to the silver halide of each of said emulsion layers.

7. A photographic element comprising a support having superposed red, green and blue light-sensitive gelatinosilver halide emulsion layers, about 1 to 12 grams per mole of silver halide of an azaindene selected from the group consisting of a hydroxy triazaindene, an amino triazaindene, a hydroxy tetrazaindene, an amino tetrazaindene, a hydroxy pentazaindene and an amino pentazaindene incorporated in at least one of said emulsion layers, and a dye developer that is both a silver halide developing agent and a dye in a layer contiguous to each of said emulsion layers that bears a complementary relationship to the color of the spectral sensitivity of the respective silver halide emulsion layers contiguous thereto.

8. A photographic element comprising a support having superposed red, green and blue light-sensitive gelatinosilver halide emulsion layers, about 1 to 12 grams per mole of silver halide of 4-hydroxy-6-methyl-l,2,3,3a,7- pentazaindene incorporated in at least one of said emulsion layers, and a dye developer that is both a silver halide developing agent and a dye in a layer contiguous to each of said emulsion layers that bears a complementary relationship to the color of the spectral sensitivity of the respective silver halide emulsion layers contiguous thereto.

9. A photographic element comprising a support having superposed red, green and blue light-sensitive gelatinosilver halide emulsion layers, about 1 to 12 grams per mole of silver halide of 4-hydroxy-6-methyl-l,3,3a,7- tetrazaindene incorporated in at least one of saidemulsion layers, and a dye developer that is both a silver halide developing agent and a dye in a layer contiguous to each of said emulsion layers that bears a complementary relationship to the color of the spectral sensitivity of the respective silver halide emulsion layers contiguous thereto.

10. A photographic element comprising a support having superposed red, green and blue light-sensitive gelatinosilver halide emulsion layers, about 1 to 12 grams per mole of silver halide of 2,4-dihydroxy-6-methyl-1,3a,7- triazaindene incorporated in at least one of said emulsion 19 20 layers, and a dye developer that is both-a silver halide 2,784,090 Carroll Mar. 5, 1957 developing agent and a dye in-a layer contiguous to each 2,835,581 Tinker et a1 May 20, 1958 of said emulsion layers that bears a complementary rela- 2,983,606 Rogers May 9, 1961 tionship to the color of the spectral sensitivity of the re- 3,034,894 Jelfreys et a1 May 15, 1962 spective silver halide emulsion layers contiguous thereto. 5

FOREIGN PATENTS References Cited in the file of this patent 5 54,212 Belgium J ly 1 1957 UNITED STATESPATENTS 2,334,864 Carroll et a1 Nov. 23, 1943 OTHER REFERENCES 2,735,769 Allen et a1 Feb 21, 1956 10 Glafkides: Photographic Chemistry, I. Fountain Pr s, 2,743,180 Carroll i Apr. 24, 1956 LOndO11(1958),Pages

Claims

1. A COLOR PHOTOGRAPHIC DIFFUSION TRANSFER PROCESS WHICH COMPRISES EXPOSING TO A SUBJECT A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT HAVING SUPERPOSED THEREON A PLURALITY OF LIGHT-SENSITIVE HYDROPHILIC ORGANIC COLLOIDSILVER HALIDE EMULSION LAYERS OPTICALLY SENSITIZED TO DIFFERENT REGIONS OF THE SPECTRUM, AT LEAST ONE OF SAID EMULSION LAYERS CONTAINING AN AZAINDENE SELECTED FROM THE GROUP CONSISTING OF A HYDROXY TRIAZAINDENE, AN AMINO TRIAZAINDENE, A HYDROXY TETRAZAINDENE, ANAMNO TETAZAINDENE, A HYDROXY PENTAZAINDENE AND AN AMINO PENTZAINDENE, AND A DYE DEVELOPER THAT IS BOTH A SILVER HALIDE DEVELOPING AGENT AND A DYE CONTIGUOUS TO THE SILVER HALIDE OR EACH OF SAID EMULSION LAYERS, PRESSING SAID PHOTOGRAPHIC ELEMENT INTO SUPERPOSED CONTACT WITH A MORDANTED RECEPTION LAYER WITH A LAYER OF ALKALINE SOLUTION THEREBETWEEN AND THEREBY DEVELOPING SILVER HALIDE IN REGIONS OF EXPOSURE AND RENDERING THE SAID DYE DEVELOPERS NONDIFFUSIBLE IN REGIONS OF EXPOSURE AND DEVELOPMENT, AND ALLOWING THE SAID DYE DEVELOPERS IN UNEXPOSED REGINS TO TRANSFER IMAGEWISE BY DIFFUSION AND IN REGISTER TO SAID RECEPTION LAYER.