US3352672A

US3352672A - Photographic direct positive color process and element

Info

Publication number: US3352672A
Application number: US358538A
Authority: US
Inventors: John C Hoppe
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1964-04-09
Filing date: 1964-04-09
Publication date: 1967-11-14
Anticipated expiration: 1984-11-14
Also published as: GB1101895A; DE1273323B

Description

Nov. 14, 1967 J, c HOPPE 3,352,672

PHOTOGRAPHIC DIRECT POSITIVE COLOR PROCESS AND ELEMENT Filed April 9, 1964 TOPOOAT LAYER LIGHT-SENSITIVE EMULSION LAYER CON TA INING DYE F ORM/NG COUPLER SUPPORT SUPP OR T MOROANT LAYER RUPTURABL E POD CON TA IN/NG PROCESS/N6 OOMPOS/T/ON TOPCOAT LAYER BLUE-SENS/T/VE EMULSION LAYER v CONTAIN/N6 YELLOW DYE -FORM/NG COUPLER INTERLAYER GREEN- SENS/T/VE EMULSION LA YER INTERLA YER RED-SENS/T/l/E EMULSION LAYER CONTAIN/N6 OYAN DYE-FORM/NG COUPLER 2O SUPPORT FIG 2 JOHN a HOPPE INVENTOR.

QW, Q @Nii AT TORNE Y S CONTAINING MAGENTA DYE-FORMING COUPLER-- United States Patent 3,352,672 Pi-IOTOGRAPHIC DIRECT POSITIVE COLOR PROCESS AND ELEMENT John C. Hoppe, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Apr. 1964, Ser. No. 358,538 18 Claims. (Cl. 963) ABSTRACT OF THE DISCLOSURE A S-substituted tetrazole is incorporated in the silver halide emulsion layer of a photographic element which includes a support having coated thereon a silver halide emulsion which forms latent images predominantly inside the silver halide grains, and, contiguous to the silver halide grains, 2. nondiifusible coupler which forms diffusible or nondiffusible dye upon reaction with oxidized aromatic primary amino color developing agent. A process for providing direct positive dye images with such photographic elements is provided, also.

This invention relates to color photography, and more particularly, to photographic direct positive color processes and photographic elements suitable for use in such processes.

Direct positive color images can be prepared by color processing direct positive silver halide emulsions having contiguous to the silver halide photographic couplers. In such processes, direct positive silver halide emulsions having silver halide grains with substantial internal sensitivity of the type described in U.S. Patent 2,592,250 are desirably utilized.

A typical process for preparing direct positive color images is by diffusion transfer, reference being made to the disclosures in British Patents 840,731 and 904,364. In such a direct positive diffusion transfer process, an image-exposed photographic element having coated thereonan internal latent image-forming silver halide emulsion with a nondiff'usible coupler that releases a diffusible dye on coupling with oxidized aromatic primary amino color developing agent contiguous to the silver halide is processed by treating the element in an alkaline processing medium in the presence of a color developing agent. Development occurs in the unexposed or positive image areas of the emulsion, resulting oxidized developing agent reacting with the colorcoupler in such areas to produce a positive dye image which thereafter is allowed to diffuse to a dye image reception layer.

Another process for preparing direct positive color images is to utilize a photographic element having coated thereon an internal latent image-forming silver halide emulsion with a nonditfusible coupler that releases a nondiifusible dye on coupling with oxidized aromatic primary amino color developing agent contiguous to the silver halide. On color development of the exposed element, silver is formed in the unexposed or positive image areas of the emulsion and resulting oxidized color developing agent reacts with the coupler in such areas to produce a positive nonditfusible dye image. The silver in the developed areas and the silver halide in the undeveloped areas of the resulting color-developed element can be readily removed to leave a positive dye image by bleaching and fixing by conventional techniques.

It is an object of this invention to provide novel lightsensitive elements or films suitable for use in direct positive color diffusion transfer processes.

It is another object of this invention to provide novel light-sensitive elements or films suitable for preparing direct positive nondiifusible images.

It is another object of this invention to provide novel photographic elements for preparing direct positive color images with internal latent image-forming silver halide emulsions of improved speed.

It is also an object of this invention to provide new photographic elements for preparing direct positive color images with internal latent image-forming silver halide emulsions having improved stability to high temperatures and high humidities.

It is likewise an object of this invention to provide novel color processes for preparing positive color images having low color density in highlight or 'D image areas.

In addition, it is an object of this invention to provide new photoelements of increased speed for preparing di rect positive color images containing a red-sensitized silver halide emulsion layer comprising silver halide grains having a substantial amount of sensitivity internal to the silver halide grains.

These and other objects of the invention are attained by means described hereinafter with respect to preferred embodiments thereof.

The present invention concerns photographic elements having superposed thereon a silver halide emulsion having substantial proportions of silver halide that form latent images predominantly inside the silver halide grains, a S- substituted tetrazole incorporated in the silver halide emulsion, and a nondiifusible photographic coupler that forms a diffusible or nondiifusible dye on reaction with oxidized aromatic primary amino color developing agent contiguous to silver halide of the emulsion.

A wide variety of 5-substituted tetrazoles can be utilized in the direct positive silver halide emulsions coated on the photographic elements of the invention. Suit-able S-Substituted tetrazoles can be represented by the formula,

/NN RO N-N H The R substituent in the above formula can be any organic radical or moiety not deleterious or antagonistic to photographic silver halide systems. Typical R substituents include alkyl radicals having 1 to 18 carbon atoms and more generally lower alkyl radicals having 1 to 6 carbon atoms; aryl radicals and preferably phenyl radicals including such substituents as carboxy, hydroxy, cyano, alkoxy, alkyl and the like; alkoxy radicals having 1 to 18 carbon atoms and more generally lower alkoxy radicals having 1 to 6 carbon atoms; cycloalkyl radicals such as those having 4 to 6 carbon atoms like cyclobutyl, cyclopentyl and cyclohexyl; acyl radicals such as benzoyl and radicals having the formula wherein R is an alkyl radical having 1 to 18 carbon atoms; heterocyclic radicals such as those having 5 to 6 atoms and including at least one of a nitrogen atom, an oxygen atom and a sulfur atom in the cyclic nucleus such as pyridyl, morpholino, piperidyl, thiazolyl and the like; and amino radicals including NH as well as alkyl substituted radicals having the formula wherein R is an alkylradical having 1 to 18 carbon atoms.

3 Typical S-substituted tetrazoles that can be utilized in the photographic elements of the invention include:

5-(4-pyridyl)tetrazole, S-dimethylaminotetrazole, 5-(3,4-dimethoxyphenyl)tetrazole, 5-cyclohexyl tetrazole,

5-n-propyl tetrazole,

5-benzoyl tetrazole, 5-(4'-carboxyphenyl)tetrazole, 5-(4-cyanophenyl)tetrazole,

5 -phenyl tetrazole, S-aminotetrazole, 5-morpholinotetrazole, 5-(4-pyridyl)tetrazole,

5 N-acetyl-3 -piperidyl) tetrazole, 5-(4-acetamidop.henyl)tetrazole, 5 3 '-hydroxyphenyl tetrazole, 5-cyclobutyl tetrazole, 5-(2'-cyanophenyl)tetrazole, and the like.

The subject 5-substituted tetrazoles can be prepared by known methods such as are described in I. Am. Chem. Soc., 80, 3908 (1959), J. Org. Chem., 24, 1650 (1959), and elsewhere in the literature.

The amount of 5-substituted tetrazole utilized in the direct positive silver halide emulsions comprising the photographic elements of the invention can be widely varied, with at least about .5, and generally about .5 to 25, grams of 5-substituted tetrazole per mole of silver halide in the silver halide emulsion being used. Preferably, 2 to grams of the 5 substituted tetrazole per mole of silver halide in the silver halide emulsion are utilized.

The silver halide emulsions utilized in the photographic or light-sensitive elements of the invention are prepared with silver halide grains wherein a substantial amount, and preferably a predominant amount, of the sensitivity to light in internal to the grain. Such emulsions are to be distinguished from emulsions containing silver halide grains that have substantial surface sensitivity and form latent images on the surface thereof. Suitable silver halides include silver bromide, silver bromoiodide, silver chloroiodide, and silver chlorobromoiodide. For a description of suitable emulsions that form latent images internal to the silver halides grains, reference is made to Davey et al., US. Patent 2,592,250; and Glafkides, Photographic Chemistry, volume 1, pages 31-2, Fountain Press, London. Typically such emulsions are those which, when measured according to normal photographic techniques by coating a test portion of the emulsion on a transparent support, exposing to a light intensity scale having a fixed time between 1x10- and 1 second, bleacln'ng 5 minutes in a 0.3% potassium ferricyanide solution at 65 F. and developing for about 5 minutes at 65 F. in Developer B below (an internal-type developer), have a sensitivity, measured at a density of 0.1 above fog, greater than the sensitivity of an identical test portion which has been exposed in the same way and developed for 6 minutes at 68 F. in Developer A below (a surface-type developer).

DEVELOPER A 4 DEVELOPER B-Continued G. Sodium carbonate, monohydrate 52.5 Potassium bromide 5.0 Sodium thiosulfate 10.0

Water to make 1 liter.

In preparing the silver halide emulsions used in layers on the photographieelements of the invention, a wide variety of hydrophilic organic colloids can be utilized as the vehicle or carrier. It is preferred to utilize gelatin as the hydrophilic colloid or carrier material althoughsuch material as polyvinyl alcohol and its water-soluble derivatives and copolymers, water-soluble copolymers such as polyacrylamide, immidized polyacrylamide, etc., and other water-soluble film-fo1ming materials that form water-permeable coats such as colloidal albumin, watersoluble cellulose derivatives, etc., can be utilized in pre-- paring the present photographic elements. Compatible mixtures of two or more of such colloids can also be utilized.

In addition to the above-described S-substituted tetrazoles, photographic silver halide emulsions used in the invention can contain the addenda generally utilized in 1 such products including gelatin hardeners, gelatin plasticizers, coating aids, chemicalssensitizers, optical sensitizers and the like.

The above-described emulsions of the invention can be coated on a wide variety of supports in accordance with usual practice. Typical supports for photographic elements of the invention include paper, polyethylene-coated paper, cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethylene-terephthalate film and related films of resinous materials and others.

The photographic silver halide emulsion layers coated on the photographic elements of the invention have contiguous to silver halide, that is, incorporated in the emulsion or in contiguous layers, at least one nondiffusible photographic color coupler that reacts with oxidized aromatic primary amino color developing agent to forma dye. Such couplers are well known in the art and are generally 5-pyrazolone, phenolic or open-chain ketomethylene compounds. For convenience of reference, nondiifusible couplers that form dilfusible dyes on color development wherein:

(l) DYE is a dye radical containing an acidic solubilizing radical; (2) LINK isa connecting or linkage radical such. as azo (N=N), azoxy o T mercuri Hg-), oxy (O-), alkylidene (includes both and wherein R is a hydrogen atom or an alkyl radical generally having 1 to 4 carbon atoms), monothio (-S),

or dithio (+S);

(3) COUP is a photographic color coupler radical such as a S-pyrazolone coupler radical, a phenolic coupler radical or an open-chain ketomethylene coupler radical, the coupler radical being substituted in the coupling position with the connecting or linkage radical;

(4) BALL is a photographically inert organic radical of such molecular size and configuration as to render the coupler nondiffusing in the element in the alkaline processing solution;

(5) SOL is either a hydrogen atom or an acidic solubilizing group when the color developing agent contains an acidic solubilizing radical, SOL always being an acidic solubilizing radical when the color developing agent is free of an acidic solubilizing group; and

(6) n is an integer of 1 or 2 when LINK is an alkylidene radical, and n is always 1 when LINK is one of the other aforementioned connecting radicals, namely, azo, azoxy, mercuri, oxy, monothio, or dithio.

The acidic solubilizing radicals attached to the diffusible dye-releasing (DDR) couplers described above can be solubilizing radicals which when attached to the coupler or developer moieties of the dyes, render the dyes diffusible in the element in alkaline processing solutions. Typical of such radicals 'ar carboxylic, sulfonic, ionizable sulfonamido, and hydroxy-substituted groups that lend to dyes negative charges.

Typical dye radical substituents (DYE) of the DDR couplers include azo, azomethine, indoaniline, indophenol, anthraquinone and related dye radicals well known in the art that exhibit selective absorption in the Visible spectrum. The dye radicals contain acidic solubilizing moietics.

When DDR couplers having the formula DYE-LINK- (COUP-BALL) as described above are reacted with oxidized color developing agent, the connecting radical (LINK) is split and a diffusible preformed acid dye (DYE) is released which diffuses imagewise to a reception layer. An acidic solubilizing group on the preformed dye lends diffusibility and mordantability to the dye molecule. The coupling portion of the DDR coupler (COUP) couples with color developing agent oxidation product to form a dye that is nondiffusible in the element because of the attached ballasting group (BALL) in a noncoupling position. In this type of DDR coupler, the color of the diifusible dye is determined by the color of the pre formed dye moiety (DYE), the color of the reaction product of color developer oxidation product and the coupler moiety (COUP) being unimportant to the color of the diflusible image.

When DDR couplers having the formula BALL-LINK- (COUP-SOL) as described above are reacted with oxidized color developing agent, the connecting radical (LINK) is split and a diffusible dye is formed with the color developing agent oxidation product and the coupling portion (COUP) of the DDR coupler which diffuses imagewise to a reception layer. Diffusibility is imparted to the dye by an acidic solubilizing group attached to a noncoupling position of the coupling portion (COUP) of the DDR coupler or to the color developing agent. The ballast portion of the DDR coupler remains immobile. In this type of DDR coupler, the color of the diffusible dye is determined by the color of the reaction product of color developer oxidation product and the coupler moiety (COUP).

When the coupler radical (COUP) in the DDR couplers is a S-pyrazolone radical, it is preferred to have substituted in the 3-position of the pyrazolone moiety an anilino group or an alkoxy group. When the coupler radical (COUP) in the DDR couplers is a cyan-forming phenolic coupler radical, I prefer to have substituted in the ortho or 2-position of the phenolic moiety a fully substituted amido group (e.g.,

wherein R is an alkyl group or a phenyl group). Also, when the connecting radical (LINK) in the DDR couplers having the formula, BALL-LINK-(COUP-SOL) is an azo radical, it is preferred that the ballasting radical (BALL) be a phenyl radical containing either a hydroxy group or an amino group (-NH substituted in the ortho or 2-position of the phenyl moiety.

The nature of the ballast groups (BALL) in the DDR coupler compounds described above is not critical as long as they confer nondilfusibility to the coupler compounds. Typical ballast groups exemplified hereinafter in the specific couplers disclosed include long chain alkyl rad icals or several short chain alkyl radicals having e.g., 8 to 22 carbon atoms, linked directly or indirectly to the coupler molecules as well as aromatic radicals of the benzene and naphthalene series, etc., linked directly or indirectly to the coupler molecules by a splittable linkage, or by a removable or irremovable but otherwise nonfunctional linkage depending upon the nature of the coupler compound. Useful ballast groups generally have at least 8 carbon atoms.

DDR couplers are known in the art. Typical suitable DDR couplers and methods for preparing such couplers are described in the following patents: Canadian Patents 602,606 and 602,607; British Patents 840,731 and 904,364; French Patents 1,224,012, 1,291,110 and 1,293,709; and Belgian Patents 578,470, 591,444, 603,213, 603,747 and 625,137.

Likewise, nondiffusible couplers that form nondiffusible dyes on color development are well-known in the art. Typical of such couplers are disclosed in the following patents: US. Patent 2,956,876 (column 5, lines 30 to 59); US. Patent 2,640,776; U.S. Patent 2,407,210 and US. Patent 2,474,293.

The coupling position of the above-described couplers is well known to those skilled in the art, this being the position on the coupler molecule that reacts or couples with oxidized color developing agent. Phenolic couplers, including a-naphthols, couple at the 4-position, open-chain ketomethylene couplers couple at the carbon atom forming the methylene moiety (e.g.,

*denoting the coupling position), and 5-pyrazolone couplers at the carbon atom in the 4-position.

The terms nondiffusing and nondiffusible used herein as applied to couplers and dyes have the meaning commonly applied to the term in color photography and denote materials which for all practical purposes do not migrate or wander through organic colloid layer, such as gelatin, comprising the sensitive elements of the invention in the presence of aqueous alkaline processing compositions. The terms diffusing and diffusible as applied to the dyes released from the DDR couplers in the present processes and the developing agents have the converse meaning and denote materials having the property of diffusing effectively through the colloid layers of the sensitive elements in the presence of aqueous alkaline processing compositions.

The photographic elements of the invention are processed with alkaline compositions in the presence of an aromatic primary amino color developing agent, p-pheny lene diamine developing agents being particularly useful. The color developing agent can be either incorporated in an aqueous alkaline composition that is applied to the present photographic elements on processing or the color developing agent can be incorporated in the light-sensitive element. Typical aromatic primary amino color developing agents include:

N,N-diethyl-p-phenylenediamine, 2-amino-5-diethylamino toluene, N-ethyl-fi-methanesulfonamido ethyl-3-methyl-4- aminoaniline, 4-amino-N-ethyl-3-methyl-N-(fi-sulfoethyl) aniline, 4-amino-N-ethyl-3 -rnethoxy-N B-sulfoethyl) aniline, 4-amino-N-ethyl-N- B-hydroxyethyl) aniline, 4-amino-N,N-diethyl-3-hydroxymethyl aniline, 4-amino-Nmethyl-N- fi-carboxyethyl) aniline, 4-amino-N,N-bis (fl-hydroxyethyl) aniline, 4amino-N,N-bis ,B-hydroxyethyl -3-methyl aniline, 3-acetamido-4-amino-N,N-bis (fi-hydroxyethyl) aniline, 4-amino-N-ethyl-N- 2,3-dihydroxypropyl -3-methyl aniline sulfate salt, 4-amino-N,N-diethyl-3- 3-hydroxypropoxy) aniline, and

the like.

When the color developing agent istused in the present photographic elements, it is advantageous to use forms that have substantial stability in emulsions such as Schitf base derivatives of primary amino developing agents. Such Schiff bases are prepared by reacting primary amino developing agents with sulfonated hydroxylated or carboxylated aromatic aldehydes of the benzene or naphthalene series. A typical Schilf base color developing agent can be prepared by reacting 2-amino-5-diethylaminotoluene and o-sulfobenzaldehyde. Other Schiff base developers that are useful as such, as salts or as sulfur dioxide complexes include:

N-ethyl-N- (lR-hydroxyethyl) -4- o-sulfobenzylideneamino) aniline sodium salt,

N,N-diethyl-4-(2,4-dihydroxybenzylideneamino)-3- methyl-aniline,

Nethyl-3-methyl-N- ,B-methylsulfonamidoethyl) -4- (2-sulfobenzylideneamino)aniline sodium salt, and the like.

Such incorporated developing agents can be activated by immersing the photographic element in an aqueous alkaline solution or by spreading an aqueous alkaline solution on the surface of the element. Such incorporated developing agents can be positioned in any layer of the present photographic elements from which the developing agents can be readily made available for development on activation with aqueous alkaline solution. Generally, such incorporated color developing agents are incorporated in layers contiguous to the light-sensitive silver halide emulsion layers, although the color developing agent can be utilized in the silver halide emulsion layers.

Fogging agents or nucleating agents are used to facilitate the reversal effect obtained with the subject internal latent image-forming silver halide emulsions. Such agents can be incorporated in the processing compositions or in one or more layers coated on the subject photographic elements. Typical of such fogging agents are hydrazines of the type described in U.S. Patents 2,563,785 and 2,5 88,- 982, ethylene bis (pyridinium) salts, reductones of the type described in U.S. Patent 2,936,308 and hydrazines or hydrazones of the type described in Belgian Patent 636,371.

The reception layer used to receive the diffused dye images on color development when DDR couplers are used in the photoelements of the invention can be either a separate receiving sheet pressed in contact with the photoelement or a layer integral with the photoelement.

When the reception layer is a separate reception sheet, the development and transfer operations can be effected by bathing either or both the exposed photographic element and the mordanted reception sheet in the developing solution before rolling into contact with each other. Alternatively, a viscous developing composition can be placed between the elements for spreading in a predetermined amount across and in contact with the exposed surface of the sensitiveelement so as to provide all of the solution required for the picture area. The viscous developing composition is desirably utilized in one or more pods or containers integral with the photographic element or the reception sheet that can be readily ruptured when development is desired, suitable viscous developer utilization techniques being disclosed in U.S. Patents 2,543,181; 2,559,643; 2,647,049; 2,647,056; 2,661,293; 2,698,244; 2,698,798; and 2,774,668. Such processing techniques utilizing viscous processing compositions and rupturable pods can also be used to color develop photographic elements containing couplers that form nonditfusible dyes.

When the reception layer for receivingthe diffusible dye is an integral part of the photosensitive assembly, it is also useful. A typical element of this type can comprise a support, a mordanted colloid layer thereon and the various emulsion layers described above coated thereover. When easily dissolved emulsions are used such as those containing polyvinyl alcohol or alkali-soluble cellulose ether phthalate vehicles, or a wet or dry stripping layer containing such vehicles is provided between the emulsions and reception layer, the developed emulsion layers can then be readily separated from the reception layer leaving the dye image thereon. Similarly, the reception layer can be initially bonded to the outer emulsion surface. In this case, it is preferred to expose through the support of the sensitive element unless the reception layer itself is transparent. Such photoelements can be processed in the same manner as those not containing integral reception layers.

The dye reception layers used in the invention can contain/any of the conventionalmordant materials for dyes. The reception layer can contain mordants such as polymers of amino guanidine derivatives of vinyl methyl ketone described in U.S. Patent 2,882,156. Other mordants include the 2-viny1 pyridine polymer metho-ptoluene sulfonate and similar compounds described in U.S. Patent 2,484,430 and cetyl trimethylammonium bromide, etc. Particularly etfective mordanting compositions are described in Belgian Patent 634,515. Typical of such mordanting compositions include at least one hydrophilic organic colloid containing a finely-divided, uniform dispersion of droplets or globules of a high-boling, waterimmiscible organic solvent in which is dissolved a high concentration of a cationic, nonpolymeric, organic dyemordanting compound for acid dyes, Other mordanting compositions described in Belgian Patent 634,515 include at least one hydrophilic organic colloid containing a finelydivided, uniform dispersion of particles of a salt of an organic acidic composition containing free acid moieties and a cationic, nonpolymeric, organic dye-mordanting compound for acid dyes. Furthermore, the reception layer or sheet can be sufiicient by itself to mordant the dye as in the case of the use of a sheet or layer of a polyamide or related polymeric material. Receiving sheets that release acidic material at a controlled rate such as are described in U.S. Patent 2,584,030 are useful.

Color developed photographic elements of the invention containing nonditfusible dye rniages on the support are treated after color development to remove silver in developed areas and to stabilize or fix silver halide in undeveloped areas. The silver in the developed areas can be bleached from the element by any of the conventional techniques used in color photography such as with aqueous baths containing water-soluble ferricyanides, dichrornates or the like bleach bath components. Likewise, the silver halide in the undeveloped areas can be stabilized or fixed by any of the conventional techniques used in silver halide photography including. the use of aqueous baths containing silver halide solvents such as water soluble thiosulfates and thiocyanates. Also, monobath compositions that can be utilized to both bleach and fix color developed photographic elements are useful.

Typical suitable bleach-fix, or so-called blix baths,

9 are disclosed in German Patent 866,605 and British Patents 746,567 and 933,008. Such 'blix baths contain as bleaching agents a complex salt of an alkali metal and trivalent iron with an organic acid having the formula 0 HO iLm-x-R i'JoH or H0i RNR t ZlOH 0 R 0 HO ii-R I L-R -ii OH wherein X is carbon, oxygen or sulfur atom or an radical, R to R being substituted or unsubstituted hydrocarbon residues and R also suitably being a hydrogen atom. Such blix baths also contain known silver halide solvents or fixing agents such as water-soluble thiosulfates. In addition, such blix baths can contain water-soluble polyethyleneoxides, or water-soluble polyalkylene oxides wherein some of the oxygen atoms are replaced by sulfur atoms. Typical of such sulfur-containing blix addenda have the formula wherein: R to R are bivalent organic radicals having 2 to carbon atoms; In is an integer of 0 to 100; n and p are integers of l to 100; Y is a radical having the formula S, SS,

or mixtures thereof, R being a lower aliphatic radical having 1 to 3 carbon atoms; and X is a hydrogen atom or an aliphatic radical which can contain a substituent for improvement the solubility of the compound (e.g., by hydroxyl, nitrile, mino, carboxylic acid or sulfonic acid groups or by a group of an acid of phosphorous). X can also be an acyl radical derived from an aliphatic monoor dicarboxylic acid.

In preparing the photographic elements of the invention, silver halide emulsions are preferably coated on photographic supports in the form of multilayer color photographic elements wherein at least three emulsion layers sensitive to difierent regions of the visible spectrum are coated on the support. For example, the uppermost light-sensitive emulsion layer is generally selectively sensitive to blue light, the next light-sensitive emulsion layeris generally selectively sensitive to green light, and the light-sensitive emulsion layer nearest the support is generally selectively sensitive to red light. Between the blue and green sensitive emulsion layers there is typically disposed a Carey Lea filter layer for absorbing blue radiation that may be transmitted through the upper-most blue sensive layer. The red, green and blue light-sensitive silver halide layers have contiguous to the silver halide (e.g., incorporated in the emulsion or in adjacent layers) a cyan-forming, a magenta-forming and a yellow-forming coupler respectively, so that dyes substantially complementary to the color sensitivities of the emulsions are formed on color development. However, the physical disposition of the red, green and blue light-sensitive silver halide layers within the present photographic elements can be widely varied in accordance with usual practice. Such multilayer photographic elements can also have other interlayers or sublayers for specialized purposes in accordance with usual practice.

Reflection prints as well as transparencies can be prepared with photographic elements of the invention that contain couplers that form nonditfusible dyes on color development, white pigmented supports for the emulsion layers being suitably used for preparing reflection prints and transparent supports being suitably used for preparing transparencies.

In another embodiment of the invention, a single layer light-sensitive element could be utilized to prepare full color images. Three types of packets of differently sensitized silver halide emulsions and their corresponding couplers for subtractive color photography can be incorporated into a single emulsion layer on a photographic support. Reference is made to Godowsky US. Patent 2,698,794 for suitable methods for preparing silver halidecolor coupler packets.

The drawings illustrate in section and in elevation typical photographic elements of the invention.

FIG. 1 of the drawings illustrates a typical photographic element of the invention wherein the feature S-substituted tetrazole and the dye-forming coupler is positioned in light-sensitive silver halide emulsion layer 11 coated on support 10. Over emulsion layer 11 is coated topcoat layer 12. Such an element is a single color element and can be processed after exposure to prepare a direct positive color image by wetting the exposed element with an aqueous processing solution containing an aromatic primary amino developing agent. It a DDR or diffusible dye-releasing coupler is used in emulsion layer 11, a receiving sheet having a reception layer which desirably contains a mordant is juxtaposed on topcoat layer 12 and the positive image formed when the DDR coupler reacts with oxidized color developing agent is allowed to diffuse and be transferred to the receiving sheet. If a coupler that forms a nondiffusible dye is used in emulsion layer 11, a dye image remains in layer 11 after color development which can thereafter be further processed to remove silver in exposed areas and silver halide in unexposed areas in the usual manner.

FIG. 2 illustrates a typical multicolor photographic element of the invention as well as a typical mordanted receiving sheet and a rupturable pod containing a processing composition that can be suitably utilized in conjunction with such photographic element. Coated on support 20 is red-sensitive emulsion layer 21 which contains a nonditfusible coupler that forms a cyan dye when reacted with oxidized color developing agent. Over red-sensitive emulsion layer 21 is coated interlayer 22 that serves to separate green-sensitive emulsion layer 23 and red-sensitive emulsion layer 21. Interlayer 22 can contain such addenda as antioxidants, nonditfusible couplers that react to form nondiffusible dyes with oxidized color developing agent from adjacent layers, filter dyes such as a magenta filter dye or the like. Green-sensitive emulsion layer 23 contains a nondiffusible coupler that forms a magenta dye on color development. Over green-sensitive emulsion layer. 23 is coated interlayer 24 that serves to separate green-sensitive emulsion layer 23 and blue-sensitive emulsion layer 25. Interlayer 24, like interlayer 22, can contain anti-oxidants, nondiflusible couplers that react to form nonditfusible dyes with oxidized color developing agent from adjacent layers, filter dyes and the like. Interlayer 24 typically contains yellow Carey Lea silver to serve as a filter for blue light. Blue-sensitive emulsion layer 25 contains a nondifiusible coupler that forms a yellow dye on reaction with oxidized color developing agent. Over blue-sensitive emulsion layer 25 is coated topcoat layer 26 that typically contains such addenda as antioxidants, ultraviolet absorbers and the like. In FIG. 2 is also illustrated a receiving sheet that can be used to receive dye images when DDR couplers are utilized in emulsion layers 21, 23 and 25. The receiving sheet comprises support 28 having coated thereon mordant layer 27 and aflixed thereto rupturable pod 29 containing processing solution. Such processing solution is typically an aqueous alkaline material and can contain anaromatic primary amino color developing agent and a fogging agent if such are not incorporated in the light-sensitive element. Light-

sensitive layers

21, 23 and 25 are direct positive silver halide emulsion layers wherein the silver halide grains have a substantial amount of sensitivity internal to the grains and at least one of such emulsion layers contains a S-substituted tetrazole. When suchemulsions are processed, they develop in positive image areas or unexposed areas. Accordingly, in the processing of an exposed photographic element of the type described in FIG. 2 of the drawings, development occurs in the unexposed areas and resulting oxidized color developing agent reacts with the color couplers in the respective red, green, and blue sensitive layers to form cyan, magenta, and yellow dyes respectively. In such subtractive The emulsion layer also contained 3.3 mg. of 2,5-dihydroxy-4-octadecyl-benzene sulfonic acid potassium salt per square foot.

F. Top-coat layer (e.g., layer N0. 26, FIG.2).A gelatin top-coat layer coated at a coverage of 50 mg. per square foot.

The gelatino-silver halide emulsions of layers A, C and E were of the type that have high internal sensitivity and low surface sensitivity as prepared by the procedure described in U.S. Patent 2,592,250. A multilayer element of color systems, couplers that form dyes that, are substanthe type described above was prepared except that silver tially complementary to the color of light recorded in the halide emulsion layers A, C and E each contained 15.0 silver halide contiguous to the couplers are used. grams of 5-(3',4-dimethoxyphenyl)tetrazole per mole of The invention is illustrated by the following examples silver halide. The two photographic elements were exof preferred embodiments thereof. posed in an intensity scale sensitometer and processed awith a developer having the following composition:

Example I A photographic element having the structure substanodium hydroxide 15.00 tially as shown in FIG. 2 of the drawings (layers to sodium Sulfite ydr u 0-50 26) was prepared by coating on a subbed cellulose ace- 20 m da lfi 0- 5 tate film support successively the following layers: P- y i e hylphenylhydrazine 0.30 A. Red-sensitive layer (e.g., layer No. 21,,FIG. 2). E hyl ne bis(gyridinium)perchlorate 0.50 A direct-positive gelatiuo-silver chlorobromoiodide (12% p-amin ethyl-li-hydroxyethyl aniline 20.00 Cl, 87% Br, 1% I) emulsion sensitized to red light con- P y hyl ne. glycol (M.W. 1540) 1.00 taining the cyan dye-forming coupler, 1-hydroxy-4-(3-n- Water to make 6 l'- OctadeY1al amY1PheI1Y1th1)'N-ethyl 3'5 dlcarboxy- The processing of the lements was carried out by immers- 2-naphthaml1de, coated at coverages of 213 mg. of gelatin ing the exposed photographic elements and a dye receiw P square foot, 115 of Per square foot and ing sheet for 10 seconds in the above-described processmg of cyan dyeiormmg ,coupler Per Squar? ing composition, bringing the receiving sheets and the foot- The emulslon layer also f of 3O photographic elementsin intimate contact for a period hYdrOXY-4'octadecylbenzene Sulfomc and Potasslum salt of 5 minutes and thereafter separating the photographic P Square footelement and the receiving sheet to exhibit a positive full- Q F" layer FIG 2)- A gelatm color image on the receiving sheet. The receiving sheetv layer contammg 100 of gFlatm P Square foot contained the mordant, dimethyl-fl-hydroxyethyl-a-(octar rfl decylamido)propyl ammonium dihydrogen phosphate. Z-naphthannde per square foot and 15 mg. of l-hydro fy- Additional samples of the two photographic elements de-. Y P Y)- -P Y 2 naphthamhde scribed above were prepared and tested in a like manner P Square footafter incubation for one week at relative humidity C- Green-Sensitive y -g-, layer N 23, F and 120 F. The values of the color D for the result- A directepositive gelatiflo-silver fihlol'obmmoiodide 4O ing transfer images on the respective receiving sheets. Cl, 8% Br, 1% I) emulsion sensitized to green light conwere determined with a densitometer and this data is taining the magenta dye-forming coupler, 1-(4-sulfosummarized in Table I below.

TABLE I Dmin Feature Addendum Fresh Coatings I 1 Week alg 1%{0 F. 50%

Red Green Blue Red Green Blue Ell ."Xf2saerrarassistants-rugs? mole of 5(3,4-din1ethoxyphenyl)tetrazole 19 16 22 22 18 .24

phenyl)-3-(4sulfoanilino)-4-(2-hydroxy 4 pentadecylphenylazo)-5-pyrazolone dipotassium salt, coated at coverages of 113 mg. of gelatin per square foot, 100 mg. of silver per square foot and 50 mg. of the magenta coupler per square foot. The emulsion layer also contained 4.4 mg. of dihydr0xy-4-octadecyl-benzene sulfonic acid potassium salt per square foot.

D. Interlayer (e.g., layer N0. 24, FIG.2).-An interlayer containing 100 mg. of gelatin per square foot, 15 mg. of Carey Lea silver per square foot and 45 mg. of l-hydroxy N [6-(2.4-di-tert-amylphenoxy)butyl]-2- naphthamide per square foot.

E. Blue-sensitive layer (e.g., layer N0. 25, FIG.-2).- A direct-positive gelatino-silver chlorobromoiodide (12% Cl, 87% Vr, 1% I) emulsion inherently sensitive to blue light containing the yellow dye-forming coupler, a-pivalyla-(3-octadecylcarbamylphenylthio) 4 sulfoacetanilide potassium salt, coated at coverages of 100 mg. of gelatin per square foot, 100 mg. of silver per square foot and 100 mg. of the yellow dye-forming coupler per square foot.

As can be observed from the data set out above in Table I, the feature 5-substituted tetrazole addendum in the silver halide emulsion layers substantially reduced the color D of the transfer prints. Similar results are obtained when 5-(4-cyanophenyl)tetrazole is substituted for the 5-(3,4'-dimethoxyphenyl)tetrazole in layers A, C and E.

Example ll 13 92 mg. of the cyan dye-forming coupler, 1-hydroxy-4-(3- n-octadecylcarbamylphenylthio)-N-ethyl-3',5' dicarboxy- Z-naphthanilide, per square foot. The emulsion also contained mg. of 2-(2-4-di-t-amylphenoxy)-5-(3,5-disulfobenzamido)benzoyl phenyl hydrazine per square foot and 1 mg. of 2,5-dihydroxy-4-octadecyl-benzene sulfonic acid per square foot. To each of the silver chlorobromide emulsions was also added a S-substituted tetrazole addendum of the invention in an amount on a molar basis equivalent to 6.0 grams of 5-(3,4' dimethoxyphenyl)tetrazole per mole of silver halide in the emulsion. Over the emulsion layer was coated a gelatin top-coat layer at a coverage of 100 mg. per square foot. For comparative purposes, samples containing no S-substituted tetrazole and comparable molar amounts of 2,3,5-triphenyl-ZH-tetrazolium chloride in the emulsion were also prepared. The photographic elements or films were then exposed in an intensity scale sensitometer and processed in the following composition:

Piperidino hexose reductone g 0.4 p-Aminoethyl-/3-hydroxyethyl aniline g 20.0 Sodium hydroxide g 15.0 Potassium bromide g 2.0 Benzyl alcohol rnl 5.0 Hydroxyethyl cellulose (1%) ml 500.00

Water to make one liter.

The above-described photographic elements were processed by immersing the element and a receiving sheet as described in Example I for seconds in the above described developing composition, brought into intimate contact for a period of 2 minutes and then separated to exhibit positive color images of cyan dye on the receiving sheet. Additional samples of the above-described photographic elements were also exposed and processed as described after an incubation period of one week at 50% relative humidity and 120 F. The monochrome transfer prints were measured for red D and D in a densitometer, such being summarized by the data set out in Table II below. The relative red speeds of the various coatings were also observed. Table 11 below records such data, both for the fresh coatings and for the incubated coatings.

14 (c) S-dimethylaminotetrazole (d) S-cyclohexyl tetrazole (e) S-n-propyl tetrazole (f) S-benzoyl tetrazole (g) 2,3,5-triphenyl-2H-tetrazolium chloride As can be observed from the data summarized in Table II, the subject feature S-substituted tetrazoles impart to the subject direct-positive color systems significant speed in 10 creases as Well as significantly reduced D values.

Example III an intensity scale sensitometer and processed in the following composition:

Percent Pipendino hexose reductone 0.4 p-Aminoethyl-B-hydroxyethyl aniline 20.0 Sodium hydroxide 12.0 Potassium bromide 2.0

Water to make one liter.

The above-described photographic elements were processed by immersing the element and a receiving sheet as described in Example I for 10 seconds in the abovedescribed developing composition, brought into intimate contact for a period of 2 minutes and then separated to exhibit positive color images of cyan dye on the receiving sheet. Additional samples of the above-described photographic elements were also tested after an incubation period of one week at 50% relative humidity and 120 F. The resulting cyan transfer prints were measured for D and D in a densitometer, such being summarized 1 Use:l at a concentration of 0.03 g. per m)le of silver as an amount equivalent to the other addenda produced no image.

2 Low In Table II, the indicated feature addenda are as fol lows:

l (a) 5-(3',4-dimethoxyphenyl)tetrazole (b) 5-(4'-pyridyl)tetrazole byt-he data set out in Table III below. The relative red speeds of the various coatings were also observed. Table III below records such data for both the fresh coatings and for the incubated coatings.

TABLE III Fresh Coatines One Week Ineybatifin 120 F.,

Feature Addenda (g./rno1e of AgX) Relative D... Dmin Relative Dmnx Dmin S eed Speed None (Control) 100 2. O7 0. 30 2. 35 1. 44 166 2. O9 0. 18 166 2. 19 0. 18 200 2. 28. 0. 16 200 2. 22 O. 34 173 2. 0. 24 159 2. 0. 40 219 2. 16 0. 18 155 2. 15 0. 18

100 2. 10 0. 50 2. 34 1. 16 71 1. 88 O. 31 2. 42 1. 12 87 1. 97 0. 24 2. 1. 36 44 1. 80 0. 26 2. 20 1. 20 S7 1. 80 0. 28 2. 38 1. 36 100 2. 03 0. 30 2. 24 1. 26 100 l. 74 0.18 80 2. l6 1. 08

High Drnnx- In Table III, the indicated feature addenda are as follows:

(h) 5-(3',4-dimethoxyphenyl)tetrazole (i) 5-phenyl tetrazole (j) 5-(4'-cyanophenyl)tetrazole (k) 5-(4-methoxyphenyl)tetrazole (l) Urazole (m) 6-nitrobenzimidazole (n) (2-amino-5-iodopyridine hydroiodide) -HgI (0) calcium nitrate Observation of the data set out in Table IIIindicates that the S-substituted tetrazole compounds utilized in the photographic elements of the invention yield substantial increases in speed and high D and low D for both fresh and incubated samples. It should also be noted that the various known antifoggants, included for comparison purposes, did not yield all of these benefits. Optimum or conventional concentrations of the various antifoggant addenda were utilized.

Example IV A photographic element having the structure substantially as shown in FIG. 2 of the drawings (layers 20 to 26) was prepared by coating on a baryta-coated paper support successively the following layers:

A. Red-sensitive layer (e.g., layer N0. 21, FIG. 2). A direct-positive gelatino-silverchlorobromoiodide (12% Cl, 87% Br, 1% I). emulsion sensitized to red light containing a cyan dye-forming coupler of the type described in US. Patent 2,367,531 coated at coverages of 200 mg. of gelatin per square foot, 40 mg. of silver per square foot, and 29 mg. of the cyan dye-forming coupler per square foot. The emulsion layer also contained 4 mg. of 2-(2- octadecyl)-5-(2-sulfo-t.-butyl)hydroquinone per square foot and 37 mg. of 2-(2,4-di-t.-amylphenoxy)-5-(3,5-disnlfobenzamido)-benz0yl phenylhydrazine per square foot.

B. Imerl'ayer (e.g., layer N0. 22, FIG. 2).A gelatin layer containing 100 mg. of gelatin per square foot and 15 mg. of 2,5-dioctyl hydroquinone per square foot.

C. Green sensitive layer (e.g., layer N0. 23, FIG. 2). A direct-positive gelatino-silver chlorobromoiodide (12% Cl, 87% Br, 1% I) emulsion sensitized to green light containing a magneta dye-forming coupler of the type described in US. Patent 2,908,573 coated at coverages of 300 mg. of gelatin per square foot, 75 mg. of silver per square foot and 75 mg. of the magneta coupler per square foot. The emulsion layer also contained 4 mg. of 2-(2- octadecyl)-5-(2-sulfo-t.-butyl)hydroquinone per square foot and 70 mg. of 2-(2,4-di-t.-amylphenoxy)-5-(3,5-disulfobenzamido)-benzoyl phenylhydrazine per square foot.

D. Interlayer (e.g., layer N0. 24, FIG. 2).-An interlayer containing 100 mg. of gelatin per square foot, 10 mg. of Carey Lea silver per square footandlS mg. of 2,5-

dioctyl hydroquinone per square foot.

E. Blue-sensitive layer (e.g., layer N0. 25, FIG. 2). A direct-positive gelatino-silver chlorobrornoiodlde (12% Cl, 87% Br, 1% I) emulsion inherently sensitive to blue light containing a yellow dye-forming coupler of the type described in French Patent 1,291,110 coated atcoverages of 3-00 mg. of gelatin per square foot, 75 mg. of silver per square foot and 95 mg. of the yellow dye-forming coupler per square foot. The emulsion layer also contained 4 mg. of 2-(2-octadecyl)-5-(2-sulfo-t.-butyl)hydroquinone per square foot and 70 mg. of 2-(2,4-di-t.- amylphenoxy)-5-(3,5 disulfobcnzamido)benzoyl phenylhydrazine per square foot.

F. Top-Coat layer (e.g., layer N0. 26, FIG. 2).-A gelatin top-coat layer coated at a coverage of 50 mg. per square foot.

The gelatino-silver halide emulsion of Layers A, C and B were of the type that have high internal sensitivity and low surface sensitivity as prepared by the procedure described in.U.S. Patent 2,592,250. A multilayer element of Color developer, 6 minutes Stop-fix, 3 minutes Water wash, 3 minutes Bleach, 3 minutes Water wash, 1.5 minutes Hardener-fix, 3 minutes Water wash, 5 minutes Butter, 2 minutes The color development was carried out at F. and the remaining baths were at 70 F. D and relative speed values were determined, such values being Summarized in Table IV below,

TABLE IV Dmlu Relative Speed Feature Addendum Red Green Blue Red Green Blue (1) None (Control) 0.36 0.34 0.44 100 100 100 P at ir s er-ts x 510131 f 3 0. 20 0.26 0.42 115 115 100 As can be observed from the data set out in Table IV, BUFFER Water ml 1000.0 the feature -su-bst1tuted tetrazole addendum 1n the silver h d 10 79 h lide emulsion layers improved the speed of the light ltr-lc an y mus a Sodium c1trate, anhydrous g 6.00 sensltlve element and resulted 1n a multlcolor dlrect Boric anhydride g 537 positive print having reduced D or improved highlight Sodium bgnzoate g 050 areas. The processing baths utilized had the following Zinc Sulfate 2 sm) compositions:

(pH 3.0 at 70 F.)

(pH 9.50 at 70 P.)

001.01: DEVELOPER Example V Water m] 1()()() Several photographic elements of the type described B 1 60 in Example II were prepared wherein the feature adnzyl alcohol m Sodium ulfit g 5 0 dendum of the 1nvent1on, 5-(3,4-d1methoxyphenyl)tetra- 4 S 3 e i 'i c i ifi g'Tggfi zole was compared with the well-known antifoggant, 4- -am1 n0 -th i fli H y 8 0 hydroxy-6-methyl-1,3,3a,7-tetrazaindene, at several conm nm0e y we /2 2 4 centrations. The antifoggant, benzotriazole, was also sodlmfl PhOSPha'te' IZHZO added to one coating for comparative purposes. The Varipotfisslum mq ous photographic elements were exposed and processed as 5-llltrobenllmldazole. described in Example III. Table V below summarizes the P methylsulfonamlde ethyl P y y relative red speed and the D and D mm values of the zine g 150-0 transferred cyan dye images for both the fresh coatings (pH 11.4 at 70 F.) and the incubated coatings.

n TABLE V Fresh Coatings One Week Iucubations 120 F.,'

50% RJH. Feature Addenda (gJmole of AgX) Relative Dme: Dmln Relative Dmnx mln Speed Speed None (Control) 100 0.98 0.28 100 1. 47 0. 84 (p) 2.0 3, 160 1. 56 0014 3,160 1. e2 0. 14 (p) 4.0 4, 470 1. 52 0. 12 4, 470 1. 66 0. 15 (p) 6.0 6,310 1. 79 0. 12 8, 910 1.62 0. 15 (g) 2.0 100 1. 22 0. 14 100 1. 25 0. 14 (g) 4.0 105 1. 54 0. 20 03 1.56 0. 1s (a) 6.0 451 1. 54 0. 12 71 1. o. 10 6.0 398 1. 53 0. 16 100 1. 66 0. 3e

STOP-FIX In Table V, the indicated feature addenda are as fol- Wate1' m1 1000.0 lows: Acetic acid, glacial ml 18.2 I I Boricacid, anhydrous g 4.76 (p) ,4-dlmethoxyphenyl)tetrazole Ammonium alum g ,75 (0) y q y-6- y -1,3,3a,7-t zamd Sodium thiosulfate, anhydrous g 71.2 (r) Benzotnazole Sodium bislllfite --3-- 18-35 As can be observed from the data set out in Table V, the d um a ta anhydrous 14-25 55 feature 5-substituted tetrazole compound utilized in the Sodium citrate g 1.71 hotographic elements of the invention produces a sub- .(pH 3.10 at 70 F.) stantial increase in speed and a high D and a low D BLEACH for both fresh and incubated samples. The photographic 1000-0 element containing the tetrazaindene compound and bensodlurfl zotriazole had substantially less red speed than the phopotasslum ferncyamdetographic element containing the feature S-substituted Pott'flsslulll bromlde tetrazole. Further, the D of the transferred dye image Borlc acid prepared with the photographic elements containing the Bone anhydl'lde S-Substit-uted tetrazole were higher than those prepared BOPaX o 3 333 with the photographic element containing the tetrazain- (P at dene compound or benzotriazole.

HARDENER-F1X The invention has been described in considerable de- Water ml 1000.0 tail with particular reference to preferred embodiments Sodium hexametaphosphate g 1.0 thereof, but it will be understood that variations and modi- Sodium sulfite g 2. fications can be eflFected Within the spirit and scope of Sodium thiosulfate-H O g 100- the invention as described hereinabove and as defined in Sodium carbonate-H O g 20.0 the appended claims. Sodium bicarbonate, anhydrous g 13.2 I claim: Formalin ml 20.0 1. A photographic element comprising a support and a direct positive silver halide emulsion layer having subwherein. R is an organic radical selected from the group consisting of analkyl radical,and aryl radical, an alkoXy radical, a cycloalkyl radical, an acyl radical, an amino radical and a heterocyclic radical having at least one atom in a cyclic ring selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom.

2. A photographic element comprising a support and a direct positive silver halide emulsion layer having substantial proportions of silver halide that form latent images inside the silver halide grains, and having disposed integral with said element and contiguous to said emulsiona nondiffusible photographic color coupler that reacts with oxidized aromatic primary amino color developing agent to forma dye, a -phenyltetrazole being incorporated in said silver halide emulsion layer.

3. A photographic element comprising a support and a red-sensitized direct positive silver halide emulsion layer wherein the silver halide forms latent images PI'CdOIHl-a nantly inside the silver halide grains, and having disposed integral with said element and contiguous to said 61111111 sion a nonditfusible photographiccolor couplerthat reacts with oxidized aromatic primary amino color developing agent to form a dye, a S-Substit-uted tetrazole being incorporated in said silver halide emulsion layer, said S- substituted tetrazole having the formula wherein R is an organic radical selected from the group consisting of an alkyl radical, an aryl radical, an alkoxy radical, a cycloalkyl radical, an acyl radical, an amino radical and a heterocyclic radical having at least one atom in a cyclic ring selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom.

4. A photographic element comprising a support with superposed red, green and blue light-sensitive direct positive hydrophilic colloid silver halide emulsion layers wherein the silver halide forms latent images predominantly inside the silver halide grains, said emulsions having incorporated therein a cyan dye-forming coupler, a magenta dye-forming coupler and a yellow dye-forming coupler respectively, said couplers being nondifiusible during development in the presence of an alkaline color developing composition containing an aromaticiprimary amino color developing agent, capable of forming diffusible dyes complementary to the color of the spectral sensitivity of the respective silver halide emulsion layers in the presence of said alkaline color developing compo-l sition by reaction with color development oxidation product of said color developing agent and having a formula selected from the group consisting of 20 (2) LINK is a connecting radical selected from the group consisting'of an arc radical, a mercuri radical, an oxy radical, an alkylidene radical, a thio radical; a dithio radical and an azoxy radical;

(3) COUP is a coupler radical selected from the group consisting of a S-pyrazolone coupler radical, a phe nolic coupler. radical and an open-chain ketomethylene coupler radical, said COUP being substituted in the coupling position with said LINK;

(4) BALL is a photographically inert organic ballast.- ing radical of such molecular size and configuration as to render said couplers nondiliusible during development in said alkaline color developing solution; (5) SOL is selected from the group consisting of a hydrogen atom and an acidic solubilizing group when said color developing agent contains an acidic solubilizing group, and SOL is an acidic solubilizing group when said color developing agent is free ofvan acidic solubilizing group; and (6) n is an integer of 1 to 2' when LINK is an alkylidene radical, and nis I when said LINK is a radical selected from the group consisting of an azo radical, a mercuri radical, an oxy radical, a thio radical, a dithio. radical and an azoxy radical; and a S-Substituted, tetrazole being incorporated in at least one of said silver halide emulsion layers, said S-substituted tetrazole having the formula wherein R isan organic radical selected from the group consisting of antalkyl radical, an aryl radical, an alkoxy radical, a cycloalkyl radical, an acyl radical, an amino radical and a heterocyclic radical having at least one atom in a cyclic ring selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom.

5. A photographic element comprising a support with superposed red, green andblue light-sensitive direct positive hydrophilic colloid silver halide emulsion layers wherein the silver halide forms latent images predominantly inside the silver halide grains, said emulsions hav ing incorporated therein a cyan dye-forming coupler, a magenta dye-forming coupler and a yellow dye-forming coupler respectively, said couplers being nondilfusible during development in the presence of an alkaline color developing composition containing an aromatic primary amino color developing agent, capable of forming nonditfusible dyes complementary to the color of the spectral.

sensitivity of the respective silver halide emulsion layers in the presence of said alkaline color developing composition by reaction with color development oxidation product of said color developing agent, and a S-substituted tetrazole being incorporated in at least one of said silver halide emulsion layers, said S-substituted tetrazole having the formula taining a nondilfusible photographic color coupler that reacts with oxidized aromatic primary amino color developing agent to form a dye and a S-substituted tetrazole selected from the group consisting of 5- (4'-cyanophenyl tetrazole,

5- 3 ',4'-dimethoxyphenyl) tetrazole, S-phenyl tetrazole, 5-(4-pyridyl)tetrazole, 5-(n-proyl)tetrazole, 5-(4-methoxyphenyl)tetrazole, S-dimethylamino tetrazole, S-cyclohexyl tetrazole, and S-benzoyl tetrazole.

7. A photographic element comprising a support and a direct positive gelatino-silver halide emulsion layer wherein the silver halide forms latent images predominantly inside the silver halide grains, said gelatino-silver halide emulsion containing a nonditfusible photographic color coupler that reacts with oxidized aromatic primary amino color developing agent to form a dye and at least about .5 gram per mole of silver halide in said emulsion of 5-(4'-cyanophenyl)tetrazole.

8. A photographic element comprising a support and a direct positive gelatino-silver halide emulsion layer wherein the silver halide forms latent images predominantly inside the silver halide grains, said gelatino-silver halide emulsion containing a nondiifusible photographic color coupler that reacts with oxidized aromatic primary amino color developing agent to form a dye and at least about .5 gram per mole of silver halide in said emulsion of 5-(3',4-dimethoxyphenyl)-tetrazole.

9. A photographic element comprising a support and a direct positive gelatino-silver halide emulsion layer wherein the silver halide forms latent images predominantly inside the silver halide grains, said gelatino-silver halide emulsion containing a nonditfusible photographic color coupler that reacts with oxidized aromatic primary amino color developing agent to form a dye and at least about .5 gram per mole of silver halide in said emulsion of S-phenyl tetrazole.

10. A photographic element comprising a support and a direct positive gelatino-silver halide emulsion layer wherein the silver halide forms latent images predominantly inside the silver halide grains, said gelatino-silver halide emulsion containing a nondiffusible photographic color coupler that reacts with oxidized aromatic primary amino color developing agent to form a dye and at least about .5 gram per mole of silver halide in said emulsion 5 of 5-(4'-pyridyl)tetrazole.

11. A photographic element comprising a support and a direct positive gelatino-silver halide emulsion layer wherein the silver halide forms latent images predominantly inside the silver halide grains, said gelatino-silver halide emulsion containing a nondiifusible photographic color coupler that reacts with oxidized aromatic primary amino color developing agent to form a dye and at least about .5 gram per mole of silver halide in said emulsion of 5-(n-propyl)tetrazole.

12. A photographic element comprising a support with superposed red, green and blue light-sensitive direct positive gelatino-silver halide emulsion layers wherein the silver halide forms latent images predominantly inside the silver halide grains, said emulsions having incorporated therein a cyan dye-forming coupler, a magenta dye-forming coupler and a yellow dye-forming coupler respectively, said couplers being nondiffusible during development in the presence of an alkaline color developing composition containing an aromatic primary amino color developing agent, capable of forming difiusible dyes complementary to the color of the spectral sensitivity of the respective gelatin'o-silver halide emulsion layers in the presence of said alkaline color developing composition by reaction with color development oxidation product of said color developing agent and having a formula selected form the group consisting of DYE-LINK-(COUP-BALL) and BALL-LINK-(COUP-SOL) wherein (l) DYE is a dye radical exhibiting selective absorption in the visible spectrum and containing an acidic solubilizing group;

(2) LINK is a connecting radical selected from the group consisting of an azo radical, a mercuri radical, an oxy radical, an alkylidene radical, a thio radical, a dithio radical and an azoxy radical;

(3) COUP is a coupler radical selected from the group consisting of a S-pyrazolone coupler radical, a phenolic coupler radical and an open-chain ketomethylene coupler radical, said COUP being substituted in the coupling position with said LINK;

(4) BALL is a photographically inert organic ballasting radical of such molecular size and configuration as to render said couplers nondiffusible during development in said alkaline color developing solution;

(5) SOL is selected from the group consisting of a hydrogen atom and an acidic solubilizing group when said color developing agent contains an acidic solubilizing group, and SOL is an acidic solubilizing group when said color developing agent is free of an acidic solubilizing group; and

(6) n is an integer of l to 2 when LINK is an alkylidene radical, and n is 1 when said LINK is a radical selected from the group consisting of an azo radical, a mercuri radical, an oxy radical, a thio radical, a dithio radical and an azoxy radical;

and 5-(3',4'-dimethoxyphenyl)tetrazole being incorporated in each of said emulsions at a concentration of about .5 to 25 grams of 5-(3,4'-dimethoxyphenyl) tetrazole per mole of silver halide in said emulsions.

13. A photographic element comprising a support with superposed red, green and blue light-sensitive direct positive gelatino-silver halide emulsion layers wherein the silver halide forms latent images predominantly inside the silver halide grains, said emulsions having incorporated therein a cyan dye-forming coupler, a magenta dyeforrning coupler and a yellow dye-forming coupler respectively, said couplers being nondilfusible during development in the presence of an alkaline color developing composition containing an aromatic primary amino color developing agent, capable of forming nondiifusible dyes complementary to the color of the spectral sensitivity of the respective silver halide emulsion layers in the presence of said alkaline color developing composition by reaction with color development oxidation product of said color developing agent, and 5-(3',4' dimethoxyphenyl) tetrazole being incorporated in each of said emulsions at a concentration of about .5 to 25 grams of 5-(3',4'- dimethoxyphenyl)tetrazole per mole of silver halide in said emulsions.

14. A process for preparing direct positive dye images which comprises treating an exposed photographic element as described in claim 1 with an aqueous alkaline processing composition in the presence of a photographic aromatic primary amino color developing agent and a fogging agent, and reacting the nondiffusible coupler in positive image areas with resulting oxidized color developing agent to form a difiusible positive dye image, said positive dye image diffusing imagewise in register to a juxtaposed reception layer.

15. A process for preparing direct positive dye images which comprises treating an exposed photographic element as described in claim 1 with an aqueous alkaline processing composition in the presence of a photographic aromatic primary amino color developing agent and a a 23 V s faggifig agent, reacting the non dii'fusibl'e coupler in the positive image areas with resulting oxidized color developing agent for a nonditfusible positive dye image on the support, add thereafter solubilizirig and removing-silver from said positive image areas and silver halide from undeveloped areas.

16. A process for preparing direct positive dye images which comprises treating an exposed photographic element as described in claim 1 with an aqueous alkaline processing composition in the presence of a photographic aromatic primary amino color developing agent and reacting the coupler in the positive image areas with resulting oxidized color developing agent to form a positive dye image,

17. A photographic element as described in claim 1 wherein the nondiffusible photographic color coupler 24 forms a diffnsible dye when reacted with oxidized aromatic primary amiho color developing agent.

181A photographic element 'as described in claim 1 wherein the nonditfusible photographic color coupler forms a nondiffusible dye when reacted with oxidized aromatic primary amino color developing agent.

References Cited UNITED STATES PATENTS 2,981,624 4/1961 Dersch et a1 96-109 3,227,552 1/1966 Whitmore 96-3 3,241,971 3/1966 Kitze 96l0l 3,260,604 7/1966 Kalenda 96101 1. TRAVIS BROWN, Primary Examiner.

Claims

4. A PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT WITH SUPERPOSED RED, GREEN AND BLUE LIGHT-SENSITIVE DIRECT POSITIVE HYDROPHILIC COLLOID SILVER HALIDE EMULSION LAYERS WHEREIN THE SILVER HALIDE FORMS LATENT IMAGES PREDOMINANTLY INSIDE THE SILVER HALIDE GRAINS, SAID EMULSIONS HAVING INCORPORATED THEREIN A CYAN DYE-FORMING COUPLER, A MAGENTA DYE-FORMING COUPLER AND A YELLOW DYE-FORMING COUPLER RESPECTIVELY, SAID COUPLERS BEING NONDIFFUSIBLE DURING DEVELOPMENT IN THE PRESENCE OF AN ALKALINE COLOR DEVELOPING COMPOSITION CONTAINING AN AROMATIC PRIMARY AMINO COLOR DEVELOPING AGENT, CAPABLE OF FORMING DIFFUSIBLE DYES COMPLEMENTARY TO THE COLOR OF THE SPECTRAL SENSITIVITY OF THE RESPECTIVE SILVER HALIDE EMULSION LAYERS IN THE PRESENCE OF SAID ALKALINE COLOR DEVELOPING COMPOSITION BY REACTION WITH COLOR DEVELOPMENT OXIDATION PRODUCT OF SAID COLOR DEVELOPING AGENT AND HAVING A FORMULA SELECTED FROM THE GROUP CONSISTING OF