US3418132A - Aldehyde gelatin hardening composition with carbocyclic diones - Google Patents

Description

United States Patent 3,418,132 ALDEHYDE GELATIN HARDENTNG COMPOSI- TION WITH CARBOCYCLIC DIONES Theodore J. Kitze, Jr., Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey N0 Drawing. Filed June 1, 1965, Ser. No. 460,583

24 Claims. (Cl. 96-411) ABSTRACT OF THE DISCLOSURE Photographic elements comprising a gelatin hardening aldehyde precursor, with carbocyclic l,3-diones in an unhardened layer are disclosed. Such elements are particularly useful in rapid access photographic recording. Photographic emulsions comprising unhardened gelatin, silver halide and the aforesaid combination of precursor and diones are also disclosed.

This invention relates to novel photographic materials and their preparation. In one of its aspects, this invention relates to novel photographic elements suitable for rapid access photographic recording. In another of its aspects, this invention relates to photographic elements which contain silver halide emulsion layers that give good photographic images and have high resistance to physical abrasion when developed quickly at high temperatures.

In the photographic recording field a very short access time, i.e., the time interval between the exposure of a photosensitive recording material and the presentation of the resulting record for visual observation, is necessary or at least very desirable. Wind tunnel and flight testing are examples of procedures where rapid access is of considerable value.

Rapid access processing can be accomplished by moving a strip of photographic recording medium through a magazine at high speed past a spot of light which moves in accordance with the signal to be measured. The recording medium is developed by wetting the photographic emulsion with a high speed alkaline processing solution which is then heated to accelerate development by passing the recording medium over a hot metal surface. The dried, developed record emerges from the magazine within a very short time, for example, one second or less.

To obtain the rapid development necessary in rpaid access processing, it is desirable to use photographic elements containing unhardened gelatin silver halide emulsion layers since such layers can be processed more quickly and have higher covering power, i.e., yield a higher density for a given amount of silver, than hardened gelatin photographic emulsion layers. However, unhardened photographic emulsion layers have poor resistance to physical abrasion and tend to wash off a support during processing. This can be overcome by processing the photographic element in a hardening developer. Unfortunately, developers of this type have poor stability and their effective hardening action decreases rapidly with age. Also, the requirement of a hardening developer severely restricts the utility of photographic elements containing unhardened photographic layers to use with these special developing solutions.

Accordingly, it is an object of this invention to provide a novel photographic element comprising an unhardened photographic emulsion layer, which element does not require the use of a hardening developer for processing.

It is another object of this invention to provide a novel photographic element comprising at least one unhardened photographic emulsion layer which is hardened during processing.

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Another object of this invention is to provide a novel photographic element comprising an unhardened gelatin silver halide emulsion layer containing a unique combination of materials, which element can be processed rapidly and evenly to give high photographic densities.

Another object of this invention is to provide novel photographic silver halide emulsions which form layers that can be processed rapidly and evenly at high temperatures.

Still another object of this invention is to provide a means for obtaining an unhardened photographic silver halide layer which can be processed rapidly and evenly to produce a hardened emulsion layer containing a silver image of good density.

Other objects of this invention will bcome apparent from an examination of the specification and claims that follow.

In accordance with this invention, it has been found that the above objects can be obtained by employing a combination of a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione with an unhardened gelatin photographic silver halide emulsion, all as described hereinafter. The use of the gelatin hardener aldehyde precursor, i.e., a compound which releases aldehyde and hardens gelatin at a pH substantially above about pH 7 but does not harden gelatin substantially below this pH, in combination with the carbocyclic 1,3-dione makes it possible to obtain the advantages of processing unhardened gelatin photographic silver halide layers without premature hardening before processing. This permits the photographic elements described herein to be stored for periods up to several weeks or more without the hardening of the unhardened gelatin photographic silver halide layers which could be expected upon storage by virtue of the presence of the hardener precursor.

One embodiment of this invention relates to a photographic gelatin silver halide emulsion comprising substantially unhardened gelatin, silver halide, a gelatin aldehyde precursor and a carbocyclic 1,3-dione in which the carbonyl groups are linked through a methylene group.

Another embodiment of this invention involves a photographic element comprising a support, an unhardened gelatin silver halide layer and, incorporated in at least one layer of said element, a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3- carbonyl groups are linked through a methylene group.

Another embodiment of this invention involves photographic materials, as described herein, which contain compounds which substantially inhibit fog without deleteriously aifecting speed and other photographic properties. The fact that certain types of antifoggants would be effective is quite unexpected since other compounds that are satisfactory antifoggants in other systems are not suitable for use in the practice of this invention, as illustrated by Example 4 which follows.

Still another embodiment of this invention is the provision of photographic elements which are particularly suited for rapid access processing by virtue of their ability to quickly pick up the required amount of developer solution to ensure complete development while avoiding excess developer pick-up which would prevent the photographic silver halide emulsion layer from drying in the very short time available in rapid access processing. As illustrated by Example 3 which follows, this very desirable result can be achieved by incorporating inert particles having a certain average particle size into at least one layer of a photographic element, provided the layer is no farther from the support for the element than a photographic silver halide emulsion layer.

The gelatin hardener aldehyde precursors employed in the practice of this invention are compounds which precede the formation of the aldehydes which harden gelatin. These compounds release or become aldehydes at a pH which is substantially above 7, for example, a pH of at least 8, and often in the range of about 9 to about 12 or more. Such compounds, when incorporated into alkaline developing solutions have been referred to in the prior art as gelatin hardeners. However, these com pounds are not hardeners per se and only form hardeners for gelatin when the pH is greater than 7, i.e., they do not harden gelatin at a pH substantially below 7, for example, a pH in the range of about 2 to about 6. The hardener precursors can conveniently be incorporated into the pho tographic silver halide emulsion layers which contain gelatin and/or in other layers, particularly gelatin containing layers of a photographic element since such layers are generally coated under acid conditions, i.e., at a pH of less than 7, generally less than about 6. Especially good results are obtained when the gelatin hardener aldehyde precursor and carbocyclic 1,3-dione are each incorporated into a photographic silver halide emulsion layer and a gelatin layer which is between the silver halide emul sion layer and the support. The preferred gelatin hardener aldehyde precursors which can be employed in the practice of this invention are alkali soluble aldehyde bisulfite addition compounds, particularly alkali metal bisulfite-dialdehyde addition products in which the aldehyde groups in the dialdehyde are separated by an open hydrocarbon chain of 2 or 3 carbon atoms, which chain preferably has no more than 2 alkyl or alkoxy substituents thereon. Suitable alkali metal bisulfites are bisulfites of alkali metals such as sodium, potassium and the like. Methylol derivatives of hydantoins or primary aliphatic nitro alcohols or hydantoin-formaldehyde condensation products are also suitable gelatin hardener aldehyde precursors for the practice of this invention.

The concentration of the hardener precursor employed in the practice of this invention is subject to wide variation. However, the most favorable results are generally obtained with fairly high concentrations of hardener precursor, for example, concentrations in the range of about to about 35%, preferably about 15 to about by weight, based on the total amount of gelatin employed in the layers. Examples of hardener precursors that can be employed in the practice of this invention include sodium formaldehyde bisulfite, glutaraldehyde bis(sodium bisulfite), fi-methyl glutaraldehyde 'bis(sodium bisul-fite), maleic dialdehyde 'bis(sodium bisulfite), methylol containing compounds such as methylol nitro methanes containing at least one methylol radical and a nitro radical attached to the methane carbon atom, as exemplified by 2-nitro-1,3-propanediol, 2 methyl Z-nitro-l-propaneol, 2-ethyl-2-nitro-3-propanediol, tris (hydroxymethyl) -nitromethane, Z-nitro 1 butanol, methylolarnides or lower alkoxy methylolamides such as monomethylol urea, dimethylol urea, dimethylol formamide, trimethylol melamine, 1,3-dihydroxymethylbenzimidazole-Z-ones, such as 1,3-di(hydroxymethyl)benzimidazole-Z one, hydantoinformaldehyde condensation products such as the condensation product of 5,5-dimethylhydantoin with formaldehyde, methylol hydantoins such as monomethylol hydantoin, dimethylol hydantoin, monomethylol 5,5- dimethylhydantoin and the like. Such compounds are disclosed in British Patent 825,544, published Dec. 16, 1959, US. Patent 2,364,017, issued Nov. 28, 1944, U8. Patent 2,494,055, issued Jan. 10, 1950, British Patent 749,326, published May 23, 1956, British Patent 676,628, published July 30, 1952, and US. Patent 2,599,518 issued June 3,. 1952.

The carbocyclic 1,3-diones employed in the practice of this invention are characterized by a 0 o H H CCH2-C-- group and contain a methylene group between two carbonyl groups which are in a 1,3 position with respect to 4 each other. These compounds are cycloaliphatic 1,3- diones which often contain 5 to 6 carbon atoms in the carbocyclic ring and can be represented by the formula:

I C H Where Z represents the atoms required to complete a carbocyclic ring, e.g., a ring having 5 to 6 carbons in the nucleus, as exemplified =by cyclopentane, cyclohexane, cyclopentene, cyclohexene, etc. The carbocyclic ring can be unsubstituted or it can contain substituents which are hydrocarbon or non-hydrocarbon. Suitable substituents include alkyls (e.g., methyl, ethyl, butyl, hexyl, etc.); aryls (e.g., phenyl, tolyl, methoxyphenyl, hexadecyloxyphenyl, naphthyl, etc.); cyano; carbalkoxy groups (e.g., carbomethoxy, carboethoxy, carbobutoxy, etc.) and the like.

The preferred carbocyclic 1,3-diones employed in practicing this invention are cycloalkane 1,3-diones having the formula:

where R and R; can be hydrogen, alkyl (e.g., methyl, ethyl, butyl, etc.), aryl (e.g., phenyl, tolyl, naphthyl, etc.), cyano or carbalkoxy (e.g., carbomethoxy, carboethoxy, etc.) and R and R; can be hydrogen, alkyl (e.g., methyl, ethyl, butyl, amyl, etc.) or aryl (e.g., phenyl, methoxyphenyl, ethoxyphenyl, hexadecyloxyphenyl, tolyl, naphthyl, etc.).

The 1,3-diketones described herein can be incorporated into a gelatin photographic silver halide emulsion layer and/or in other layers, particularly gelatin containing layers of a photographic element. Like the gelatin hardener precursors, these compounds are water soluble and will diffuse throughout a photographic element. It is particularly advantageous to incorporate the 1,3-diketones into a gelatin layer which is between a silver halide emulsion layer and the support. In such cases the silver halide emulsion layer generally also contains 1,3-diketone and, in the preferred case, each layer will also contain a gelatin hardener aldehyde precursor.

Typical carbocyclic 1,3-diketones that can be employed in the practice of this invention include:

5 ,5 -dimethylcyclohexane- 1,3-dione, S-phenylcyclohexane-1,3-dione,

5- (pmethoxyphenyl) -cyclohexane-1,3-dione, 4-cyano-S-phenylcyclohexane-1,3-dione,

5 o-decyloxyphenyl cyclohexane- 1,3-dione,

5 o-hexadecyloxyphenyl cyclohexanel ,3-dione, cyclohexane-1,3-dione, 4,6-dicarbethoxy-S-methylcyclohexane-1,3-dione, 4,6-dimethyl-5-phenylcyclohexane-1,3-dione, 4,6-dicyano-5,S-dimethylcyclohexane-1 ,3-dione, 4-phenyl-5 ,5 -diethylcyclohexane-l ,3-dione, S-methyl-S-phenylcyclohexane-1,3-dione, cyclopentene-1,3-dione, 4,4-dimethylcyclopentane-1,3-dione and the like. The concentration of the 1,3-diketones employed in the practice of this invention is subject to wide variation but does not generally exceed the concentration of the hardener precursor. Satisfactory results are obtained with equimolar ratios of 1,3-diketone to hardener precursor although mole ratios in the range of about 0.5 :1 to about 1:1 are generally employed.

A- typical procedure for preparing the 1,3-diketones employed in the practice of this invention involves the condensation of O S-unsaturated ketones with malonic acid esters, cyanoacetic acid esters, or aryl acetic acid esters in the presence of basic catalysts such as sodium ethoxide. The resulting compounds which contain car balkoxy groups can be readily hydrolyzed to the corresponding carboxy compounds and decarboxylated. The starting B-unsaturated ketones are prepared by condensation of ketones with aldehydes and ketones. The preparation of 5,5-dimethylcyclohexane-l,3-dione can be given as an example of the preparation of a typical cyclic 1,3- diketone. The preparation involves the condensation of mesityl oxide with diethyl malonate in the presence of sodium ethoxide. This is followed by hydrolysis of the ester group present in the resulting intermediate and decarboxylation. A number of the cyclopentane-l,3- diones are described in the literature as for example cyclopentane-l,3-dione (Chem. Abstract, 43, 4908), 4,4- dimethylcyclopentane-l,3-dione (Chem. Abstract, 42, 4536c) and many other carbocyclic 1,3-diones are described in U.S. Patent 2,944,899 issued July 12, 1960.

As already indicated, certain classes of compounds can be used in the photographic elements described herein to inhibit fog upon development. It was not to be expected that these particular compounds would be effective to inhibit fog because compounds having closely related chemical structures which have been used as antifoggants in the photographic field do not give the desired protection in the photographic silver halide emulsions and elements of this invention. The antifoggants which can be employed with the photographic silver halide emulsions of this invention are nitro benzodiazoles in which nitrogen is the sole hetero atom, S-mercapto tetrazoles and anthraquinone-Z-sulfonic acids and their alkali metal salts. The preferred nitro benzodiazoles are S-nitrobenzodiazoles, sometimes named as 6-nitrobenzodiazoles due to the presence of two nitrogen atoms in the heterocyclic ring, as exemplified by S-nitroindazole, S-nitrobenzimidazole and the like. The 5-nitrobenzodiazoles are employed in antifoggant concentrations which are generally about .1 to about 50 millimoles per mole of silver halide and preferably about 1 to about millimoles. Compounds of this type are disclosed in Us. Patent 2,214,446, issued Sept. 10, 1940.

The S-mercapto tetrazole antifoggants which can be employed in the practice of this invention include those having the formula:

where R is an aliphatic or aromatic radical containing up to carbon atoms and SX is a mercapto function. The mercapto function or group can be in the free (--SH) form or in the salt (fiSX) form. X is a cation, for example, hydrogen, an alkali metal such as sodium, potassium, ammonium or an organic amine residue of such amines as triethyl amine, triethanol amine, morpholine and the like. In addition, many of the mercapto heterocyclic nitrogen compounds can be in the tautomeric form, for example, in the thione form, in which case the labile hydrogen atom in the mercapto function becomes bonded to the nitrogen atom and the group becomes a thiocarbonyl C=S) group. The term S-mercapto tetrazole, as employed herein, is intended to cover compounds in which the mercapto function is in any of these forms. R can be hydrocarbon or non-hydrocarbon and includes alkyl or aryl radicals which can contain atoms or groups other than carbon and hydrogen. Suitable atoms or groups which can be present in R together with hydrogen and carbon include, for example,

alkoxy, phenoxy, halogen, cyano, nitro, amino, substituted amino, 'sulfo, sulfamyl, substituted sulfamyl, sulfonylphenyl, sulfonylalkyl, fluosulfonyl, sulfonamidophenyl, sulfonamidoalkyl, carboxyl, carboxylate, carbamyl, carbamylphenyl, carbamylalkyl, carbonylalkyl, carbonylphenyl and similar groups. Examples of S-mercapto tetrazoles which can be employed in the practice of this invention include l-phenyl-S-mercapto tetrazoles, l-ethyl-S- mercapto tetrazole, l-a-naphthyl mercapto tetrazole, 1- cyclohexyl-S-mercapto tetrazole, and the like. The 5-mercapto tetrazoles are employed in antifoggant concentrations which are generally about .1 to 50 millimoles per mole of silver halide and preferably about 1 to about 15 millimoles. Compounds of this type are disclosed in US. Patent 2,403,927 issued July 16, 1946, and US. Patent 2,271,229, issued Jan. 27, 1942.

The anthraquinone sulfonic acids or salts employed in the practice of this invention are derivatives of anthraquinone and contain a sulfonic acid function in the 2 position. The sulfonic acid function can be in the free (-SO H) form or in the salt (SO M) form. M is a cation, for example, hydrogen or an alkali metal such as sodium, potassium, ammonium, an organic amine residue of such amines as triethyl amine, triethanol amine, morpholine, and the like. Suitable anthraquinone sulfonic acids or salts which can be employed in the practice of this invention include, for example, anthraquinone-Z-sulfonic acid, anthraquinone-2,6-disulfonic acid, anthraquinone- 2,7-disulfonic acid, anthraquinone-1,2-disulfonic acid, and the like as well as salts, particularly alklai metal salts thereof. The anthraquinone derivatives are employed in antifoggant concentrations which are generally about .1 to 50 millimoles per mole of silver halide and preferably about 1-15. Compounds of this type are disclosed in US. Patent 2,504,593, issued Apr. 18, 1950.

As pointed out previously, the ability of the photographic elements of this invention to pick up a sufficient amount of developer solution to ensure complete development While avoiding excess developer pick up can be achieved by the incorporation of inert particles into one or more layers of the element. The inert particles employed for this purpose are water insoluble, solid particles and have an average size within a particular range. Thus, the inert particles have a diameter in the range of about 7 to about 15 microns, preferably about '8 to about 12 microns. In addition, no more than about 5%, by weight, preferably less than about 3%, by weight, of the particles have a diameter in excess of 20 microns. The size of the inert, discrete particles employed in practicing this invention can be readily determined by conventional procedures employed in the prior art for this purpose.

The inert particles employed in the practice of this invention include any of the water insoluble particulate organic or inorganic compounds which can be used to provide the photographic element with the required surface characteristics. Examples of suitable inert particles include starch, barium sulfate, calcium carbonate, cellulose esters such as cellulose acetate propionate, cellulose ethers such as ethyl cellulose, synthetic resins such as polymeric esters of acrylic and methacrylic acid, as exemplified by poly methyl methacrylate, polyvinyl resins such as polyvinyl acetate and polyvinyl alcohol, polycarbonates homo and copolymers of styrene, inorganic oxides such as zinc oxide, silica, glass, titanium dioxide, magnesium oxide and aluminum oxide, as well as hardened gelatin grains, calcium sulfate, calcium carbonate, barium carbonate and the like.

The discrete particles can be incorporated into one or more layers on an emulsion side surface of a support in a photographic element. These particles are incorporated into at least one layer which is no farther from the support than the emulsion layer, i.e., they are incorporated in the photographic silver halide emulsion layer and/or a layer lying between said emulsion layer and the support. The inert particles can also be put into both the photographic silver halide emulsion layer and an adjacent layer.

The solid inert particles are incorporated into the photographic element of this invention using any method which will achieve uniform dispersion of the particles in one or more layers of the element. For example, the inert particles are not light sensitive and can be dispersed directly in a photographic silver halide coating solution or they can be dispersed in an aqueous solution or dispersion of the silver halide binding agent, which solution is mixed with a photographic silver halide emulsion prior to coating the latter to form a light sensitive layer. In general, the solid inert particles are present in the photographic element in concentrations in the range of about to about 150, preferably about to about 100 mg./ft. of support.

Various colloids can be used with gelatin as vehicles or binding agents in the photographic emulsions and elements of this invention. However, unhardened gelatin or a gelatin derivative which is primarily unhardened gelatin, should be used for at least part, e.g., at least 10%, by weight, of the binder in one or more layers of a photographic element. Other binding agents that can be used with the unhardened gelatin are colloidal materials such as colloidal albumin, cellulose derivatives, synthetic resins such as polyvinyl compounds, acrylamide polymers or the like. Although gelatin can be the sole binding agent, it is often advantageous to employ combinations of binding agents, particularly mixtures of gelatin with aqueous dispersions of polymerized ethylenically unsaturated compounds. The binding agent is generally coated at coverages in the range of about to about 1000, preferably about 50 mg. to about 300 mg./ft. of support.

The silver halides employed in the preparation of the light sensitive coatings described herein include any of the photographic silver halides as exemplified by silver bromide, silver iodide, silver chloride or mixed silver halides such as silver chlorobromide or silver bromoiodide. These photographic silver halides can be coated at silver coverages of about 30 to about 150, preferably 45 to about 90 mg./ft. of support. The silver halides used in the photographic elements of this invention can be those which form latent images predominantly on the surface of the silver halide grains or those which form latent images predominantly inside the silver halide crystals, such as those described in Davey and Knott US. Patent 2,592,250. The silver halide emulsions can be developing out emulsions, print out, or direct print emulsions which sometimes also are developed as described in French Patents 1,368,647 and 1,329,911.

The photographic layers described herein can be superimposed upon a wide variety of supports. Typical flexible supports include those generally employed for photographic elements such as cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethylene terephthalate film and related films or resinous materials as well as thin glass films, paper, and the like. Supports such as paper which are partially acetylated or coated with baryta or an a-olefin polymer, particularly a polymer of an a-olefin containing 21O carbon atoms, as exemplified by polyethylene, polypropylene, ethylene butene copolymers and the like, can also be employed.

The photographic emulsions and elements of this invention can also contain additional addenda, particularly those known to be beneficial in photographic materials of this nature. For example, they can contain additional stabilizers or antifoggants such as organic azoles, azaindenes, mercaptans, metal salts such as cadmium, lead, mercury, gold, or other noble metal salts, spectral sensitizers such as the cyanines, merocyanines, complex (trinuclear) cyanines, complex (trinuclear) merocyanines, styryls, hemicyanines, speed increasing materials, such as polyalkylene glycols, onium salts and thio ethers, plasticizers, coating aids such as anionic, non-ionic and amphoteric surface active compounds and the like. The photographic silver halide emulsions can also be chemically sensitized with compounds of the sulfur group such as sulfur, selenium and tellurium sensitizers, noble metal salts such as gold, or reduction sensitized with reducing agents or combinations of such materials. The photographic elements can contain fluorescent brighteners such as stilbenes, coumarins, benzothiazoles, benzoxazoles, imidazoles, etc. Suitable fluorescent brighteners are described in McFall et al. US. Patent 2,933,390, Geigy British Patent 786,234, Seyler US. Patent 3,025,242 and Leonar-YVerke German Patent 1,150,274. The photographic elements can also contain incorporated developing agents, for example, amino-phenols, polyhydroxybenzenes such as hydroquinone, 3-pyrazolidones such as 1- phenyl-3-pyrazo1idone and the like, either alone or in combination.

This invention can be further illustrated by the following examples of preferred embodiments thereof although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless otherwise specifically indicated. 7

EXAMPLE 1 As already indicated, a photographic element comprising unhardened gelatin, photographic silver halide, gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione, as described herein, is stable upon storage and can be developed without using a hardening developer. Furthermore, such elements can be processed more readily to a higher density without deleterious hardening before processing. To illustrate, an unhardened gelatin layer containing glutaraldehyde bis(sodium bisulfite) (49 ing/ft?) in gelatin (220 mg./ft. is coated on a paper support as a control (Coating No. 1). A second coating (Coating No. 2) is prepared in the same manner except that the gelatin layer contains 5,5-dimethyl cyclohexane 1,3-dione (24 mg./ft. Over each gelatin layer is coated a silver bromoiodide gelatin emulsion at a coverage of 58 mg. of gelatin and 72 mg. of silver per square foot of support. Each of the coatings is aged for an identical period of several weeks, exposed on a sensitometer and processed for 20 seconds in Kodak D-72 (1:1) Developer. The emulsion hardness before processing and D after processing of the coatings are as follows:

Coating Melting Point mnx The melting point is determined by immersing a sample in water which is heated at the rate of 6 F. per minute with brushing of the emulsion surface with a soft bristle brush. The temperature at which there is evidence of emulsion removal is taken as the melting point. An unhardened layer is one which has a melting pointless than about F. when subjected to this procedure.

As can be seen from the above results, each of the coatings can be processed without the use of a hardening developer. However, the omission of the carbocyclic 1,3- dione from the coating results in hardening of the coating prior to processing which reduces D Similar results are obtained when the above procedure is repeated with other carbocyclic 1,3-diones such as 5- phenylcyclohexane-1,3-dione, cyclohexane-1,3-dione, 4,6- dicyano-5,5-dimethylcyclohexane-1,3-dione, cyclopentane- 1,3-dione and 4,4-dimethylcyclopentane-1,3-dione.

EXAMPLE 2 The gelatin hardener precursor and carbocyclic 1,3-dione can be incorporated into an unhardened gelatin photographic silver halide emulsion layer which also contains developing agents. To illustrate, an unhardened silver bromoiodide gelatin emulsion containing incorporated developing agcnts, a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione is coated on a paper support at the following coverage per square foot: mg. silver, 270 mg. gelatin, 88 mg. hydroquinone, 18 mg. 1-phenyl-3- pyrazolidone, 77 mg. glutaraldehyde bis( sodium bisulfite),

23 mg. 5,5-dimethyl cyclohexane l,3-dione. The coating (A) is aged for several weeks and then exposed on a sensitometer and processed in an alkaline activator containing no developing agent. For comparison purposes, the same procedure is employed to prepare and process a coating (B) from which the carbocyclic 1,3-dione is omitted. The unprocessed aged coating (A) has a melting point below 110 F. while coating (B) which contains no carbocyelic 1,3-dione melts substantially above 110 F. The processed aged coating (A) exhibits a D which is more than higher than coating (B).

Substantially the same results are obtained when glutaraldehyde bis(sodium bisulfite) in the above procedure is replaced with sodium formaldehyde bisulfite, fi-methyl glutaraldehyde bisulfite, and monomethylol dimethyl hydantoin.

EXAMPLE 3 As pointed out previously, optimum development characteristics can be obtained, particularly in surface application processing, by incorporating inert particles having brightening agent of the type described in Crawford U.S.

Patent 3,025,242 is also added to the gelatin underlayer at a coverage of 7 mg. per square foot. The photographic elements are exposed on an oscillograph and processed in a conventional surface application processor such as a Kodak Ektaline 200 Processor, manufactured by the Eastman Kodak Company, Rochester, NY. In this type of processor, the photographic paper is passed through a tray containing a developer solution which is applied by rollers. The photographic paper is then passed around a developing drum which, in this case, is maintained at a temperature of about 200 F. and run at a speed of 200 feet per minute. By contacting the hot drum the photographic paper is flash developed in about 0.3 second. The photographic paper is then passed through a tray containing stabilizing solutions which are uniformly applied by rollers. The photographic paper is then pulled around a stabilizing drum which, in this case, is heated to 375 P. where flash stabilization take place in approximately 0.6 second. This also results in drying the coated paper. The processing results obtained with coatings containing the different batches of silica particles are as follows:

Percent, by Average weight, silica Coating particle size particles with Processing results of silica, diameters microns greater than microns 1 4 1 Low Dm, uneven de velopment. 2 8 3 High Dim, even development. 3 15 5 Tacky surface, high stain.

The unhardened photographic silver halide emulsions described herein can contain certain classes of compounds which substantially inhibit fog upon development. To illustrate, an unhardened silver bromoiodide gelatin emulsion is coated on a paper support over a gelatin layer at a coverage of 145 mg. of silver per square foot and 88 mg. of gelatin per square foot. The coverages per square foot in the gelatin underlayer are as follows: 220 mg. gelatin, 16 mg. 5,5-dimethyl cyclohexane 1,3-dione, mg. glutaraldehyde bis(sodium bisulfite), 16 mg. l-phenyl- 3-pyrazolidone, 62 mg. hydroquinone, 105 mg. titanium dioxide (average particle size 2 microns), 0.018 cc. triazinyl amino stilbene brightening agent of the type described in Crawford US. Patent 3,025,242 which improves background reflectance and 10 mg. silica (average particle size 8 microns, less than 5% over 20 mi crons). Various antifoggants are added to the gelatin underlayer at optimum levels, as indicated in the table below. The coatings are exposed in a high intensity short duration sensitometer for 10 seconds through a step wedge having a 0.15 log E speed difference between each step. The coatings are developed for 2.6, 10 and 20 seconds in an activator comprising the following ingredients: g. potassium hydroxide, 40 g. sodium bisulfite, 2 g. potassium bromide and fixed, washed and dried. The speed is reported in the following table as the number of visible steps at the development times reported. Fog density is read on a reflection densitometer with magnesium oxide as the standard. The concentrations of antifoggant and processing results obtained are set forth in the following tables:

TABLE 1 Antitoggant Coating Antifoggant content (millimoles/mole silver halide) 1 None 7. 4 3. 5 13. 7 6.2 0.8 4. 1 510 9 Sodium anthraquinone sulfonate 5.9

TABLE 2 Speed (visible steps) Fog density Coating 2.6 sec. 10 sec. 20 sec. 2.6 sec. 10 sec. 20 sec 0 28 1. O0 1. 32 17 16 0. 06 0. 10 0. 12 0. 10 0. 53 U. 86 0. 10 0. 0. 92 0. 05 0. l1 0. 13 0. 06 0. 46 1. 30 0.06 0.20 0. 27 0. O9 0. 90 1. 30 0.07 0.21 0.25

*Steps obscured by fog density.

From Table 2 it can be seen that most of the antifoggants restrict fog to a degree under the 2.6 second development conditions. However, the necessary fogspeed relationship which must be maintained in a photographic product is obtained only with the antifoggants employed in coatings 2, 5, 7 and 9.

Results very similar to those attained with coatings 2, 5, 7 and 9 are obtained when the above procedure is repeated using 1-ethyl-5-mercapto tetrazole, l-cyclohexyl- S-mercapto tetrazole and disodium anthraquinone-2,6-disulfonate.

Thus, this invention provides the art with photographic elements containing unhardened gelatin photographic silver halide layers that can be processed quickly without the need for a hardening developer. These unhardened gelatin silver halide layers can be stored for long periods prior to processing without hardening. It is also significant that the invention provides photographic elements which contain nitrobenzodiazoles in which nitrogen is the sole hetero atom, S-mercapto tetrazoles and anthraquinone-Z-sulfonic acids and their alkali metal salts which are selective in their action with the unhardened gelatin photographic silver halide emulsions layers described herein. It has also been found that these same antifoggants are also effective in unhardened gelatin photographic silver halide layers, particularly those containing incorporated developers such as polyhydroxybenzenes and 3-pyrazolidones, even when the gelatin hardener precursor and the carbocyclic 1,3-dione are not present.

Although the invention has been described in considerable detail with reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be eflective without departing from the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A photographic silver halide emulsion comprising substantially unhardened gelatin, silver halide, a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group.

2. A photographic silver halide emulsion comprising substantially unhardened gelatin, silver halide, a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and the carbocyclic ring contains 5 to 6 carbon atoms in the nucleus.

3. The photographic silver halide emulsion according to claim 2 in which the gelatin hardener aldehyde precursor is an alkali soluble bisulfite-aldehyde addition product.

4. The photographic silver halide emulsion of claim 2 in which the gelatin hardener aldehyde precursor is an alkali soluble bisulfite-dialdehyde addition product in which the aldehyde groups are separated by an open hydrocarbon chain of 2-3 carbon atoms.

5. A photographic silver halide emulsion comprising substantially unhardened gelatin, silver halide, a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group, the mole ratio of dione to precursor being in the range of about 0.5 :1 to about 1:1.

6. A photographic silver halide emulsion comprising substantially unhardened gelatin, silver halide, glutaraldehyde bis(sodium bisulfite) and 5,5-dimethyl cyclohexane 1,3-dione, the mole ratio of dione to bisulfite being in the range of about 0.5:1 to about 1:1.

7. A photographic silver halide emulsion comprising substantially unhardened gelatin, silver halide, a gelatin hardener aldehyde precursor, a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and a nitrobenzodiazole antifoggant in which nitrogen is the sole hetero atom.

8. A photographic silver halide emulsion comprising substantially unhardened gelatin, silver halide, a gelatin hardener aldehyde precursor, a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and a nitrobenzodiazole antifoggant.

9. A photographic silver halide emulsion comprising substantially unhardened gelatin, silver halide, a gelatin hardener aldehyde precursor, a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and, as antifoggant, an anthraquinone containing a sulfonic acid function in the 2 position.

10. A photographic element comprising a flexible support, an unhardened gelatin silver halide layer and, incorporated in at least one layer of said element, a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group.

11. A photographic element comprising a paper support, an unhardened gelatin silver halide layer and, incorporated in at least one layer of said element, a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and the carbocyclic ring contains 5 to 6 carbon atoms in the nucleus.

12. The photographic element according to claim 11 in which the gelatin aldehyde precursor is an alkali metal bisulfite-dialdehyde addition product in which the aldehyde groups are separated by an open hydrocarbon chain of 23 carbon atoms.

13. A photographic element comprising a flexible support, an unhardened gelatin aldehyde precursor and, incorporated in at least one layer of said element, a carbocyclic l,3-dione in which the 1,3-carbonyl groups are linked through a methylene group, the mole ratio of dione to precursor being in the range of about 0.5 :1 to about 1:1.

14. A photographic element comprising a flexible support, an unhardened gelatin silver halide layer and, incorporated in at least one layer of said element, glutaraldehyde bis(sodium bisulfite) and 5,5-dimethyl cyclohexane 1,3-dione, the mole ratio of dione to bisulfite being in the range of about 0.521 to about 1:1.

15. A photographic element comprising a flexible support, an unhardened gelatin silver halide layer and, incorporated in at least one layer of said element, a gelatin hardener aldehyde precursor, a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and a nitrobenzodiazole antifoggant in which nitrogen is the sole hetero atom.

16. A photographic element comprising a flexible sup port, an unhardened gelatin silver halide layer and, incorporated in at least one layer of said element, a gelatin hardener aldehyde precursor, a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and inert particles having an average diameter in the range of about 7 to about 15 microns, with no more than about 5%, by weight, of said particles having a diameter in excess of about 20 microns, said inert particles being incorporated in no layer which is farther from the support than said silver halide layer.

17. A photographic element comprising a flexible support, an unhardened gelatin silver halide emulsion layer containing a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and, between said support and said silver halide emulsion layer, an unhardened gelatin layer containing a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group.

18. The photographic element according to claim 16 in which the gelatin hardener aldehyde precursor is glutaraldehyde bis(sodium bisulfite), the dione is 2,2- dimethyl cyclohexane-1,3-dione and the inert particles are silica.

19. A photographic element comprising a flexible support, an unhardened gelatin silver halide emulsion layer containing a gelatin hardener aldehyde precursor and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group and, between said support and said silver halide emulsion layer, an unhardened gelatin layer containing a gelatin hardener aldehyde precursor, a carbocyclic 1,3-dione in which the l-3-carbonyl groups are linked through a methylene group and inert particles having an average diameter in the range of about 7 to about 15 microns with no more than about 5%, by weight, of said particles having a diameter in excess of about 20 microns, the ratio of dione to precursor in each layer being in the range of about 0.5 :l to about 1:1.

20. The photographic element according to claim 19 in which the aldehyde precursor is glutaraldehyde bis- (sodium bisulfite), the dione is 5,5-dimethyl cyclohexane 1,3-dione and the inert particles are silica.

21. A photographic element comprising a flexible support, an unhardened gelatin silver halide emulsion layer and, incorporated in at least one layer of said element,

a gelatin hardener aldehyde precursor, a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group, a fluorescent brightening agent and inert particles having an average diameter in the range of about 7 to about 15 microns, with no more than about 5%, by weight, of said particles having a diameter in excess of about 20 microns, said inert particles being incorporated in no layer which is farther from said support than said silver halide emulsion layer.

22. A photographic silver halide emulsion comprising substantially unhardened gelatin, silver halide, a gelatin hardener precursor, an incorporated developer, and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group.

23. A photographic element comprising a flexible support, an unhardened gelatin silver halide layer and incorporated in at least one layer of said element, a gelatin hardener aldehyde precursor, a developer, and a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group.

24. A photographic element comprising a flexible support, an unhardened gelatin silver halide layer and,

incorporated in at least one layer of said element, a gelatin hardener aldehyde precursor, a developer, a carbocyclic 1,3-dione in which the 1,3-carbonyl groups are linked through a methylene group, and inert particles having an average diameter in the range of about 7 to about 15 microns, with no more than about 5% by weight, of said particles having a diameter in excess of about 20 microns, said inert particles being incorporated in a layer not farther from the support than said silver halide layer.

References Cited UNITED STATES PATENTS 2,309,492 1/1943 Albers et a1. 96-109 X 2,725,305 11/1955 Allen et al 96-1l1 X 2,805,159 9/1957 Unkauf 9675 3,232,764 2/1966 Allen et al 96111 X NORMAN G. TORCHIN, Primary Examiner.

R. E. FICHI'ER, Assistant Examiner.

U.S. Cl. X.R. l06125; 260117