US3428455A - Optically sensitized photographic element containing a developing agent - Google Patents

Description

United States Patent 3,428,455 OPTICALLY SENSITIZED PHOTOGRAPHIC ELE- MENT CONTAINING A DEVELOPING AGENT Theodore J. Kitze, .lr., Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed May 28, 1965, Ser. No. 459,912 U.S. Cl. 96-76 17 Claims Int. Cl. G03c 1/48, 1/10 ABSTRACT OF THE DISCLOSURE Radiation sensitive photographic elements having an unhardened silver halide emulsion layer containing silver halide developing agent, are spectrally sensitized with a solubilized oxacarbocyanine or benzimidazole carbocyanine dye.

-This invention relates to the use of certain spectral sensitizers in photographic materials useful in rapidprocessing systems employing a stabilization procedure to eliminate stain therein.

Normal photographic processing of conventional silver halide materials after exposure includes the essential steps of development, fixing, washing and drying. These essential steps consume an appreciable amount of time and in many cases the time required for the completion of each step cannot be shortened without lessening the quality of the final picture.

Silver halide elements containing developing agents incorporated therein are being widely used in applications requiring rapid processing. The incorporation of develapplication of two processing solutions and provide a substantially dry, stabilized processed print in thirty seconds or less. The development stage usually involves a two to five second application of the alkaline activator solution. The development step is followed by a twoto five-second application of the stabilizer solution. Since no washing step is involved, elements of the photographic emulsion remain in the stabilized print. Among these elements are oxidized and unoxidized developer chemicals and dyes utilized to extend the spectral sensitivity of the silver 'halide. These retained chemicals tend to produce stain in the non-image background areas of the processed print. I

This stain is especially prevalent in unhardened emulsion layers utilized in rapid processing techniques since layers of this type may be processed very rapidly due to their high permeability to processing solutions. Layers of this type also exhibit higher covering; power, i.e., they opers directly into the silver 'halide element rather than in the process produces more rapid development and permits the use of simplified processing chemistry and equipment. Thus, a silver halide element containing a developing agent, after exposure, may be developed by merely wiping the surface of the silver halide with a sponge, a rubber roller or other applicator wet with an alkaline solution so that the support is not soaked. Another method of applying the solution includes pressing the exposed layer against a pad or web'moistened with an alkaline solution. In rapid processes of this type, it has also been the practice in the art to treat the residual silver halide without removing it, in such a way is to stabilize it against the effects of further exposure from actinic light during handling and storage. It is known (see for example, Stabilization Processing of Films and Papers by H. Russell, E. Yackel and J. Bruce, PSA Journal, Photographic Science and Technique, volume 16B, August 1950) that to achieve this result the residual silver halide must be converted into a stable complex silver compound which may be allowed to remain in the print, thereby eliminating the need for a washing step.

Compounds for reacting with the residual silver halide to so convert it are usually compounds containing a doubly-bonded sulfur atom or an SH linkage (see British Patents 636,981 and 693,632). One method for stabilizing a photographic print is to treat it with an alkali metal thiocyanate or an ammonium thiocyanate for a few seconds or minutes and then dry it without washing out the soluble chemicals therein. Instead of using a thiocyanate, one may employ an alkali metal or ammonium thiosulfate or a thiourea or a thioglycollic acid. Usually the time of treatment is chosen so as to be just sufiicient to convert the residual silver halide into the complex silver compound which is allowed to remain in the element. Normally the thiosulfates and thioureas are used in acid solution, the thioglycollic acid in alkaline solution and the thiocyanates in either acid or alkaline solutions.

Many rapid-access processing machines utilize surface yield higher density for a given amount of silver than similar emulsion layers which have been hardened before exposure thereof. These properties of unhardened emulsion layers are well known in the art, having been described by T. H. James and L. J. Fortmiller in the article, Dependence of Covering Power and Spectral Absorption of Developed Silver on Temperature and Composition of the Developer, Photographic Science and Engineering, vol. 5, No. 5, September-October 1961, pp. 297-304 and by D. A. Nepela in the article, Effect of Development Temperature on Covering Power of a Developed Silver Image, pp. 305-310 ibid.

It is well known, however, that unhardened photographic silver halide emulsion layers exhibit poor resistance to physical abrasion and may even separate from the support during processing. These defects may be eliminated by processing the photographic element in a hardening developer as described in Allen and Burness British Patent 825,544. Developers of this type have poor stability since their effective hardening action tends to decrease rapidly with age. It is possible, however, to incorporate in the unhardened layers of the photographic element a hardener-precursor which releases hardener at the alkaline pH utilized for development of the exposed element. Particularly useful hardener-precursors are those which form aldehyde-type hardeners in alkaline processing solutions.

It is desirable to incorporate spectral. sensitizing dyes in unhardened silver halide elements containing incorporated developing agents, which elements are designed for rapid stabilization processing. For satisfactory results, such spectral sensitizers should become colorless during processing or they must be rapidly bleached from the emulsion in order to reduce or eliminate stain therefrom. Spectral sensitizing dyes containing solubilizing groups have been employed in photographic elements processed in the conventional manner, i.e., using a washing cycle following development and fixation.

It is an object of my invention to provide photographic silver halide elements comprising an incorporated developer agent and a spectral sensitizer which has low stain propensity when the exposed elements are processed in rapid stabilization processes.

It is a further object of my invention to provide unhardened photographic elements comprising a silver halide emulsion layer, an incorporated silver halide developing agent and a spectral sensitizer which exhibits low stain propensity when the exposed element is processed in a rapid stabilization process.

It is also an object of my invention to provide an unhardened photographic element containing a silver halide emulsion layer having therein a silver halide developing agent, a hardener-precursor and a spectral sensitizer which exhibits low stain propensity when the exposed, radiation-sensitive element is processed in a rapid stabilization process.

These and other objects will become apparent from an examination of this specification and claims that follow.

I have found that many solubilized dyes satisfactory for use in elements designed for conventional processing are ineffective for providing stain reduction in the shorter processing times of rapid stabilization processes which do not include a washing step. I have found, however, that wherein X, G,' G, R R and R have the meanings given above; A represents the same substitnents as R Z may be selected from the class consisting of CR R and NR wherein R R and R represent lower alkyl groups of from 1-4 carbon atoms. In the above formula and in the appended claims, both G and G may represent more than one substituent in the aryl nucleus. It will be noted that in these formulas, at least one of R and R contains a solubilizing group, preferably a sulfoalkyl, carboxyalkyl or diaminoalkyl substituent.

when solubilized oxacarbocyanine or solubilized benzim- 10 Typical carbocyanine dyes useful in my invention may idazole carbocyanine dyes are included in photographic be represented by substitution of the groups listed below elements having an unhardened silver halide emulsion into the appropriate general formula:

FORMULA I G G R; R2 R; Y

hydrogen diehloro ethyl snlfopropyl hydrogen oxygen chloro chloro sulfopropyl sulfopropyl ethyl oxygen phenyl chloro sulfobutyl sulfopropyl ethyl oxygen chloro bromo sulfobntyl sulfobutyl hydrogen oxygen dibromo dibromo carboxyethyl ethyl hydrogen oxygen chloro phenyl sulfopropoxy ethyl hydrogen oxygen chloro chloro sulfobutoxy ethyl ethyl oxygen FORMULA II G G R1 R2 Z A dichloro diehloro sulfobutyl suliobutyl N-CzHa ethyl dibromo dibromo sulfobutyl ethyl NC2H5 ethyl hydrogen hydrogen sulfobutyl sulfobutyl NC2H5 ethyl CH3 hydrogen dichloro methyl ethyl 0 carboxymethyl CHs CH; hydrogen diehloro methyl ethyl 0 dlethylaminoethyl layer which contains a hardener-precursor and a develop- The photographic elements of my invention preferably ing agent, the element may be processed in a rapid stabilicontain, along with the hardener-precursor, a carbocyclic zation process with little or no stain. The preferred sensi- 0 1,3-dione stabilizer. The elements preferably also contain tizing dyes of the invention are represented by Formulas water-insoluble, inert solid particles to impart desirable I and II below: surface characteristics to the element.

The preferred hardener-precursors are aldehyde hard- I O Y ener-precursors, such as aldehyde bisulfite addition products, methylol derivatives and other aldehyde releasing G compounds. Aldehyde releasing compounds are of various types and are described in Allen and Burness British Pat- N N ent 825,544; Baldsiefen US. Patent 2,364,017; Orkin U.S. L, 1,, Patent 2,494,055; Harriman US. Patent 2,591,542; Schwartz US. Patent 2,599,518; British Patent 676,628 wherein G and 6' each are members of a class consistand it sh e t ing of hydrogen, an aryl nucleus such as phenyl; halogen The hardener precursors may be added to the unhardsuch as chloro, dichloro, bromo, dibromo, chlorobromo; ened layers in the photographic element at a concentraalkyl such as propyl, butyl, hexyl, etc.; alkoxy, hydroxy, tion of about 5-35 and preferably between 15 and carbethoxy, amino, etc.; R represents hydrogen, a lower 30%, based on the total amount of vehicle in the un alkyl of from 1 to 4 carbon atoms, such as methyl, ethyl, hardened layers. propyl or butyl, or aryl, such as phenyl; X is an anion; Y Typical suitable carbocyclic 1,3-diones include those represents S, 0, Se or NR wherein R is hydrogen or lower having the formula: alkyl, e.g., methyl, ethyl, propyl or butyl; R and R each are selected from the class consisting of lower alkyl (1-4 A H carbon atoms), sulfoalkyl, carboxyalkyl, sulfoalkoxyalkyl I 2 or dialkylaminoalkyl wherein the alkyl groups contain from 1-4 carbon atoms, and at least one of R and R is selected from the class consisting of sulfoalkyl, carboxyalkyl, sulfoalkoxyalkyl, or dialkylaminoalkyl, the 5 alkyl groups containing from 1-4 carbon atoms; and,

wherein Z represents the atoms required to complete a carbocyclic ring, e.g., having 5 to 6 carbons in the nu- H cleus as cyclopentane, cyclohexane, cyclopentene, cyclo- Z N hexene, etc., such that the said ring may be unsubstituted or substituted with groups, such as an alkyl (e.g., methyl, G C=O1-IO=CHC G ethyl, butyl, hexyl, etc.); an aryl (e.g., phenyl, tolyl, methoxyphenyl, hexadecyloxyphenyl, naphthyl, etc.); N N X9 cyano; a carbalkoxy (e.g., carbomethoxy, carboethoxy, 7 carbobutoxy, etc.), etc.

The preferred carbocyclic 1,3-diones include cycloalkane-1,3-diones shown to advantage by formula: B.

wherein R and R each represent a group selected from the class consisting of hydrogen; an alkyl (e.g., methyl, ethyl, butyl, etc.); an aryl (e.g., phenyl, tolyl, naphthyl, etc.); cyano; a carbalkoxy (e.g., carbomethoxy, carboethoxy, etc.); and R and R are each selected from the class consisting of hydrogen; an alkyl (e.g., methyl, ethyl, butyl, amyl, etc); an aryl (e.g., phenyl, methoxyphenyl, ethoxyphenyl, hexadecyloxyphenyl, tolyl, naphthyl, etc.).

Typical examples of compounds included in Formula A that are used to advantage according to my invention are:

(1) 5,5-dimethylcy-clohexane-1,3-dione (2) S-phenylcyclohexane-1,3-dione (3) 5- (p-methoxyphenyl) cyclohexane- 1,3-dione (4) 4-cyano-5phenylcyclohexane-1,3-dione (5) 5- o-decyloxyphenyl cyclohexane- 1,3-dione (6) 5-(o-hexadecyloxyphenyl)cyclohexane-1,3-dione (7) cyclohexane-l,3-dione (8) 4,6-dicarbethoxy-5-methylcyclohexane-1,S-dione (9) 4,6-dimethyl-5-phenylcyclohexane-1,3-dione (l) 4,6-dicyano-5,5-dimethylcyclohexane-1,3-dione (11) 4-phenyl5,5-diethylcyclohexane-1,3-dione (12) -methyl-S-phenylcyclohexane-1,3-dione (13) cyclopentene-1,3-dione (14) 4,4-dimethylcyclopentane-1,3-dione These and other compounds of Formula A are used to advantage according to my invention. They are preferably added to the unhardened layers at a concentration of about 0.5 to 1 mole per mole of hardener-precursor present, although other concentrations may be used if desired.

The cyclohexane-1,3-diones are prepared by the condensation of 01.,[3-111'1S8tl11flt6d ketones with malonic acid esters, cyano acetic acid esters, or aryl acetic acid esters in the presence of basic catalysts such as sodium ethoxide. The resulting compounds which contain carbalkoxy groups can be readily hydrolyzed to the corresponding carboxy compounds and decarboxylated. The starting afiunsaturated ketones are prepared by condensation of ketones with aldehydes and ketones. The preparation of 5,5-dimethylcyclohexane-1,3-dione may 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-1,3-dione (Chem. Abstract, 42, 4536e), etc.

The above addendamay be incorporated into the silver halide layer and/ or into a layer contiguous thereto.

The inert particles employed are water insoluble, solid particles and have a diameter in the range of about 7 to about 15 microns, preferably about 8 to about 12 microns and 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 polymethyl methacrylate, polyvinyl resins, such as polyvinyl actate 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 hard ened gelatin grains, calcium sulfate, 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 20 to about 150, preferably about 30 to about rug/ft. of support.

Various colloids can be used as vehicles or binding agents in the photographic elements of this invention. Among such agents are gelatin, or other colloidal materials such as colloidal albumin, cellulose derivatives, synthetic resins, such as polyvinyl compounds, acrylamide polymers or the like. It is often advantageous to employ combinations of binding agents. Suitable combinations include mixtures of gelatin with aqueous dispersions of polymerized ethylenically unsaturated compounds. The binding agents, particularly gelatin, are usually coated at coverages in the range of about 50 to about 1000, preferably about 50mg. 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. preferably 45 to about 90 mg./ft. of support. The silver halides used in the photographic elements of this invention may 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 U.S. Patent 2,592,250. The silver halide emulsions may be developing out emulsions or direct print emulsions which sometimes also are developed as described in French Patents 1,368,647 and 1,329,911 and Fix U.S. application 338,605, now Patent No. 3,326,689 filed Jan. 20, 1964.

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 very thin glass film, paper, and the like. Supports such as paper which are partially acetylated or coated with baryta or an wolefin polymer, particularly a polymer of an a-olefin containing 2-10 carbon atoms as exemplified by polyethylene, polypropylene, ethylene butene copolymers and the like, can also be employed.

The photographic elements of this invention can also contain additional addenda, particularly those known to be beneficial in one or more layers of a photographic element. For example, these elements can contain stabilizers or anti-foggants such as organic azoles, azaindenes, mercaptans, metal salts, such as cadmium, lead, mercury, gold or other noble metal salts, speed increasing materials, such as polyalkylene glycols, onium salts, thioethers, gelatin hardeners, 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 groups 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, courmarins, 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-Werke German Patent 1,150,274.

The invention can be further illustrated by the following examples of preferred embodiments thereof.

EXAMPLE 1 A paper support which contained no hardeners was coated with a gelatin solution to yield the following coverages per square foot: Gelatin, 220 mg.; 1,3cyclohexane dione, 16 mg; glutaraldehyde bis-bisulfite, 55 mg; l-phenyl-3-pyrazolidone, 16 mg.; hydroquinone, 62 mg. These samples of this coating were then overcoated with photographic emulsions as follows:

Sample I was overcoated with an unhardened silver bromoiodide emulsion which contained 90 mg. of 3,3- ethylene-thiacyanine iodide,

per silver mole at a silver coverage of 180 mg./ft. and a gelatin coverage of 260 rng./ft.

Sample II was overcoated with a similar emulsion under identical conditions and differed only in that it contained 90 mg. of anhydro-5,5-dichloro-9-ethyl-3,3-di (3-sulfopropyl)-oxacarbocyanine hydroxide, sodium salt,

, 9 ornonlonzsoma GHCHZCRSOB per silver mole as a spectral sensitizer.

Sample III was overcoated with a similar emulsion under identical conditions, but the emulsion did not contain a spectral sensitizer and was designed to serve as a control.

The above three samples were exposed to a tungsten light source to yield a density of 0.6 when processed through an activator solution comprising 70 grams of potassium hydroxide, 40 grams of sodium bisulfite and 2 grams of potassium bromide per liter, for 2.6 seconds at 70 F. and then through a stabilizer solution comprising 300 grams of ammonium thiocyanate, 40 grams of sodium bisulfite, 10 grams of sodium thiosulfate pentahydrate and grams of sodium phosphate, monobasic per liter for 3.0 seconds in a two-stage rapid access processor. The stabilized prints were then examined for background stain.

Sample: Back-ground stain I Green. II 1 Gray-white. III (controlno dye) Gray-white.

1 Contains dye from my invention.

Example 2 Five samples similar to those described in Example 1, but containing the dyes listed below, were exposed and processed as described in Example 1 to yield the data listed below.

Sample I-Control (as described in Example 1).

Sample IIControl+9O mg. of 3ethyl-5-[(3-ethyl-2- (3H) -benzoxazolylidene )isopropylidene] rhodanine,

per silver mole.

Sample IIIControl-| mg. of 3-ethyl-5-[(3-methyl- 2(3H) thiazolinylidene)ethylidene] 2-thio-2,4-oxazolidine-dione,

per silver mole.

Sample IV-Control+90 mg. of anhydro-5,6-dichloro- 1,3 cliethyl 3 (3-sulfopropyl)benzimidaz0looxacarbo cyanine hydroxide,

CzH5 O a \O=CHCH=CHC/ C1 \e/ N N 12th. rimomomso per silver mole.

Sample V-Control+90 mg. of anhydro-5,5'-dichloro- 9 ethyl 3,3-di(3-sulfopropyl)oxacarbocyanine hydroxide, monosodium salt.

To illustrate that the action of the dyes of my invention are truly unique in the rapid stabilization process and not due merely to the presence of solubilization groups thereon, the following six samples were prepared and processed as described in Example 1. The control sample was identical to the control described in Example 1.

Sample IControl (no dye).

Sample II-Control+90 mg. of 3-carboxymethyl-5-[(3- ethyl-2 (3H) -benzoxazolylidene) ethylidene] rhodanine,

per silver mole.

9 Sample IH--Control+90 mg. of 3-carboxymethyl-5- [(3 methyl 2(3H)thiazolinylidene)isopropylidene]rhodanine,

per silver mole.

Sample IV-Control+90 mg. of 3-(3-dimethylaminopropyl) 5 [(3-methyl-2-thiazolidinylidene)ethylideneJ- 2-thio-2,4-oxazolidinedione,

per silver mole.

Sample V+Contnol+90 mg. of 3-ethy1-5-[1-(4-sulfo butyl)-4(1H)-pyridylidene]-rhodanine, sodium salt,

per silver mole.

Sample VIControl|-90 mg. of anhydro-5,5' ,6, 6-

tetrachloro 1,1 -diethyl 3,3-di(3-sulfobutyl)benz1m1dazolo-carbocyanine hydroxide,

dnzomonzcmsoa wa per silver mole.

| CHzCHzCHzCHgSOa 1 Contains a dye of my invention.

The advantages of the rapid access stabilization process and in particular the use of my elements containing certain spectral sensitizers to decrease stain therein is readily apparent. One of the chief advantages lies in the fact that the usual developing solution containing developing agent is dispensed with. As is well known, the usual developing solutions have a very short life partly because the developing agent therein readily oxidized in the presence of air even when restrainers are incorporated in the developer. Therefore, the worker must continually change developing solutions. Since I incorporate the developing agent into the photographic element, there is no need to use a developing agent in the alkaline treating solution although this can be done if desired. Also, with the elimination of the usual washing step, the total processing time for a print has been substantially decreased, yet the prints obtained by the use of the elements of my invention are found to be substantially free of stain even though they are unwashed.

The developing agents may be incorporated into various types of silver halide emulsions, for example, the well-known direct positive type of emulsion, particularly those disclosed in the Kendall et al. ,U.S. patent application Ser. No. 35,987, filed June 29, 1948, now Patent No. 2,541,472, issued Feb. 13, 1951, may contain the developing agent and be processed in a manner similar to that described in the above examples. The result, of course, is to obtain a direct positive stabilized image from the original copy. The spectrally-sensitized emulsions of my invention are preferably gelatino-silver halide emulsions. However, they are not limited thereto since other water-permeable organic colloid vehicles may be used for dispersing the silver salt and developing agent, e.g., polyvinyl alcohol, partially hydrolyzed polyvinyl esters and cellulose esters, etc.

The developing agents useful in elements processed according to my invention include, for example, conventional silver halide developing agents such as hydroquinones, 3-pyrazolidones, p-aminophenols, etc. as Well as precursors thereof. Combinations of these developer agents may also be utilized. The concentrations of silver halide developing agents in my elements may be varied over a wide range. The amount selected will normally be based on the ability to provide images of adequate density as well as providing an emulsion having optimum keeping properties.

The silver halide stabilizing agents mentioned above may be used as in the above examples in aqueous solution but it is preferable to make the stabilization bath acidic to counteract alkali present in the developing solution. The alkali of the developing solution is not especially critical since carbonate, caustic alkali and borates all give useful results, although strong alkali is preferred in the alkaline treating solution since it will increase the rate of development.

Although the photographic elements of my invention may be immersed in the alkaline and stabilizing solutions, I prefer merely to moisten the surface of the exposed elements with these solutions. Thus, in the case of paper supports, the support does not become excessively wet and the drying time is thereby greatly reduced or even eliminated.

It will be apparent from the foregoing description of my invention that a substantial proportion of the sliver compounds remain in the emulsion after the stabilizing treatment. This differs from the customary fixing and washing in which the intent is to remove the residual silver halide from the emulsion.

It will be understood that the examples and modifications described herein are illustrative only and that my invention is to be taken as limited only by the scope of the appended claims.

I claim:

1. A radiation-sensitive photographic element comprising a support having thereon an unhardened silver halide emulsion layer, a silver halide developing agent and at least one spectral sensitizing dye selected from the class consisting of solubilized oxacarbocyanine and benzimidazole carbocyanine dyes.

2. A radiation-sensitive photographic element comprising a support having thereon an undhardened silver halide emulsion layer, a silver halide developing agent and a spectral sensitizer selected from the class consisting of '(a) oxacarbocyanine dyes having the following forwherein G and G each represents a member of the class consisting of hydrogen, an aryl nucleus, an alkyl substituent, hydroxy, an amino group and halogen; R represents a member of the class consisting of hydrogen, lower alkyl substituent of from 1 to 4 carbon atoms, and an aryl nucleus; at represents an anion, and Y represents a member of the class consisting of S, 0, Se and NR, wherein R is a member of the classconsisting of hydrogen and lower alkyl; R and R each are selected from the class consisting of alkyl substituents of from 1 to 4 carbon atoms, sulfoalkyl, carboxyalkyl, sulfoalkoxyalkyl and dialkylaminoalkyl, all of said alkyl substituents containing from 1 to 4 carbon atoms, at least one of R and R being selected from the class consisting of said sulfoalkyl, carboxyalkyl, and dialkylaminoalkyl substituents; and

(b) benzimidazole carbocyanine dyes having the following formula:

wherein X, G, G, R R and R have the same meanings given above and A has the same meaning as R at least one of R R and A being selected from the class consisting of said sulfoalkyl, carboxyalkyl and diaminoalkyl substituents; and Z is selected from the class consisting of CR R and NR wherein R R and R each represents a lower alkyl group of from 1 to 4 carbon atoms.

3. The element of claim 2 in which the silver halide layer consists of a direct-positive silver halide emulsion.

4. The element of claim 2 in which the silver halide layer contains a hardener-precursor and a carbocyclic 1,3-dione stabilizer.

5. The element of claim 4 in which the carbocyclic 1,3-dione stabilizer is selected from the class represented y wherein Z represents the atoms required to complete a carbocyclic nucleus having from to 6 carbons in the nucleus.

6. The element of claim 4 in which the carbocyclic 1,3-dione stabilizer is selected from the class represented y wherein 'R and R each represent a group selected from the class consisting of hydrogen; an alkyl substituent; an aryl group; and a carbalkoxy group; and R and R are each selected from the class consisting of hydrogen; an alkyl substituent; and an aryl group.

7. The element of claim 4 in which the silver halide layer contains a combination of a hydroquinone and a 3-pyrazolidone silver halide developing agent.

8. The element of claim 7 in which the silver halide layer contains water-insoluble particulate material having a diameter in the range of from about 7 to 15 microns.

9. The element of claim 2 wherein the dye is anhydro-S,S',6,6-tetrachloro 1,1 diethyl 3,3 di(3-sulfo- 'butyl)benzimidazolocarbocyanine hydroxide.

10. The element of claim 2 wherein the dye is why dro-5,6-dichloro 1,3 diethyl-3-(3-sulfopropyl)benz imidazolooxacarbocyanine hydroxide.

11. The element of claim 2 wherein the dye is anhydro-5,5'-dichloro 9 ethyl 3,3 di(3-sulfopropyl)oxacarbocyanine hydroxide, sodium salt.

12. A radiation-sensitive photographic element comprising a support having thereon an unhardened gelatin silver halide emulsion layer containing (a) from 15 to 30%, based on the weight of the gelatin in said layer, of glutaraldehyde bis-bisulfite as hardener precursor;

(b) 0.5 to 1 mole, based on the hardener precursor, of

1,3-cyclohexanedione stabilizer;

(c) sufl'icient hydroquinone to develop said silver halide upon activation after exposure; and

(d) a spectral sensitizing quantity of anhydro- 5,5 dichloro 9 ethyl 3,3 di(3 sulfopropyl)- oxacarbocyanine hydroxide, sodium salt.

13. In a rapid access stabilization process for the formation of a stable image in a photographic silver halide material which comprises exposing a photographic element having an unhardened silver halide emulsion layer containing at least one silver halide developing agent; developing a silver image in said exposed layer by treatment with an alkaline solution; immediately thereafter stabilizing said layer with a solution comprising at least one compound selected from the group consisting of a thiourea, thioglycollic acid and the alkali metal, alkaline earth and ammonium salts of a thiocyanate and a thiosulfate; and drying said layer; the improvement which comprises spectrally sensitizing said silver halide with a spectral sensitizer selected from the class consisting of solubilized oxacarbocyanine and solubilized benzimidazole carbocyanine dyes.

14. In a rapid access stabilization process for the formation of a stable image in a photographic silver halide material which comprises exposing a photographic element having an unhardened silver halide emulsion layer containing at least one silver halide developing agent; developing a silver image in said exposed layer by treatment with an alkaline solution; immediately thereafter stabilizing said layer with a solution comprising at least one compound selected from the group consisting of a thiourea, thioglycollic acid and the alkali metal, alkaline earth and ammonium salts of a thiocyanate and a thiosulfate; and drying said layer; the improvement which comprises spectrally sensitizing said silver halide with a spectral sensitizer selected from the class consisting of (a) oxacarbocyanine dyes having the following wherein G and G each represent a member of the class consisting of hydrogen, an aryl nucleus, an alkyl substituent, hydroxy, an amino group and halogen; R represents a member of the class consisting of hydrogen, lower alkyl substituents of from 1 to 4 carbon atoms, and an aryl nucleus; X represents an anion, and Y represents a member of the class consisting of S, 0, Se and NR, wherein R is a member of the class consisting of hydrogen and lower alkyl; R and R each are selected from the class consisting of alkyl substituents of from 1 to 4 carbon atoms, sulfoalkyl, carboxyalkyl, sulfoalkoxyalkyl and dialkylaminoalkyl, all of said alkyl substituents containing from 1 to 4 carbon atoms, at least one of R and R being selected from the class consisting of said sulfoalkyl, carboxyalkyl, and dialkylaminoalkyl substituents; and

(b) benzimidazole carbocyanine dyes having the following formula:

wherein X, G, G, R R and R have the same meanings given above and A has the same meaning 13 as R at least one of R R and A being selected from the class consisting of said sulfoalkyl, carboxyalkyl and diaminoalkyl substituents; and Z is selected from the class consisting of CR R and NR wherein R R and R each represents a lower alkyl group of from 1 to 4 carbon atoms.

15. In a rapid access stabilization process for the formation of a stable image in a photographic silver halide material which comprises exposing a photographic element having an unhardened silver halide emulsion layer containing at least one silver halide developing agent; developing a silver image in said exposed layer by treatment with an alkaline solution; immediately thereafter stabilizing said layer with a solution comprising at least one compound selected from the group consisting of a thiourea, thioglycollic acid and the alkali metal, alkaline earth and ammonium salts of a thiocyanate and a thiosulfate: and drying said layer; the improvement which comprises spectrally sensitizing said silver halide with anhydro 5,5',6,6 tetrachloro 1,1 diethyl 3,3- di( 3-sulfobutyl)benzimidazolocarbocyanine hydroxide.

References Cited UNITED STATES PATENTS 3,369,902 2/1968 Abbott 96-76 2,184,013 12/1939 Leermakers 96--106 3,380,828 4/1968 Kitze et al. 96102 NORMAN G. TORCHIN, Primary Examiner.

M. F. KELLEY, Assistant Examiner.

US. Cl. X.R.