US3708303A

US3708303A - Photographic elements and processes lithographic silver halide element containing a 1-(amidophenyl)-5-mercaptotetrazole sensitizing agent and development process of using same

Info

Publication number: US3708303A
Application number: US00105993A
Authority: US
Inventors: E Salesin
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1971-01-12
Filing date: 1971-01-12
Publication date: 1973-01-02
Anticipated expiration: 1990-01-02

Abstract

High contrast photographic elements comprising a support coated with a silver halide emulsion wherein the halide comprises at least about 50 mole percent chloride and containing a 1(amidophenyl)-5-mercaptotetrazole, provide improved speed control without undesired change in sensitometric characteristics. Methods for processing such elements in a continuous transport processing machine are also described.

Description

United States Patent [191 Salesin 1 Jan. 2, 1973 [541 PHOTOGRAPHIC ELEMENTS AND PROCESSES LITHOGRAPHIC SILVER HALIDE ELEMENT CONTAINING A l- (AMIDOPHENYL)-5- MERCAPTOTETRAZOLE SENSITIZING AGENT AND DEVELOPMENT PROCESS OF USING SAME [75] Inventor: Eugene D. Salesin, Rochester, N.Y.

[73] Assignee: Eastman Kodak Company,

Rochester, N.Y.

[22] Filed: Jan. 12, 1971 [2]] App]. No.: 105,993

Related U.S. Application Data [63] Continuation-in-part of Ser. No. 754,967, Aug. 23,

1968, abandoned.

[52] US. Cl. ..96/107, 96/109, 96/95, 96/76 R, 96/66 R, 96/33 [5 l] Int. Cl. ..G03c 5/24, G030 l/28, G03c 5/30 [58] Field of Search....96/l07, 65, 33, 109, 66, 76 R, 96/95 Primary Examiner-J. Travis Brown Assistant Examiner-Won H. Louie, Jr. Attorney-Robert W. Hampton, Bernard D. Wiese and Myron B. Kurtzman [5 7 ABSTRACT High contrast photographic elements comprising a support coated with a silver halide emulsion wherein the halide comprises at least about 50 mole percent chloride and containing a l-(amidophenyl)-5-mercaptotetrazole, provide improved speed control without undesired change in sensitometric characteristics. Methods for processing such elements in a continuous transport processing machine are also described.

11 Claims, No Drawings PHOTOGRAPHIC ELEMENTS AND PROCESSES LITHOGRAPHIC SILVER I-IALIDE ELEMENT CONTAINING A l-(AMlDOPHENYL)-S- MERCAPTOTETRAZOLE SENSITIZING AGENT AND DEVELOPMENT PROCESS OF USING SAME The application is a continuation-in-part of Ser. No. 754,967 filed Aug. 23, 1968, by Eugene D. Salesin, now abandoned.

BACKGROUND OF THE INVENTION 1. Field ofthe lnvention This invention relates to photographic materials, their preparation and use. One aspect of the invention relates to a continuous process for processing exposed high contrast photographic elements in a continuous transport processing machine employing photographic elements containing a l-(amidophenyl)--mercaptotetrazole. Another aspect of the invention relates to photographic emulsions containing such a l- (amidophenyl)-5-rnercaptotetrazole, which results in desired restraining of development upon processing without undesired change in dot quality, contrast or fog of high contrast images.

2. Description of the Prior Art ln the graphic arts field, where it is desired to make photographic line and halftone reproductions, it is customary to employ emulsions providing extremely high contrast images. During development, the developed areas grow autocatalytically at a very high developing rate to produce extremely high contrast which is necessary for half-tone patterns and other such images requiring high dot quality. Developers utilized with lith type photographic films are quite different in composition from typical black-and-white film developers. ln order to obtain very high contrast and sharp halftone dots, it has been the practice to formulate developers for such films from essentially hydroquinone, an alkaline development activator, alkali metal bromide and a low level of sulfite ion. The low level of sulfite ion partially stabilizes the developer solution for a short period of time and is achieved in all present commercial developers of this type by use of sodium formaldehyde bisulfite, which acts as a sulfite ion buffer.

Such developer solutions for high contrast lith films presently used in continuous transport processing machines have a number of disadvantages. The photographic quality obtained with a given film is usually inferior to that obtained in careful tray processing. The sensitivity of high contrast films to developer exhaustion products and development in general as well as variations in local developing agent concentration makes these films vulnerable to localized changes in sensitometric properties. For example, the dots in a high contrast film can be distorted and exhibit size changes depending on the orientation and direction of travel through the machine processor. This undesirable dot distortion is manifested in changes in the H and D curve of high contrast films which are processed in con tinuous transport processing machines. 1

Problems in the graphic arts field have also been. encountered with regard to speed loss where materials are incorporated in a photographic element in an effort to improve dot quality. For example, it has been attempted in the past to incorporate l-phenyl-S-mercaptotetrazole in coatings for photographic elements in order to improve dot quality. Such coatings have not proved satisfactory because an undesirable speed loss is produced which is believed to be a result of the leaching of 1-phenyl-5-mercaptotetrazole out from the coatings. The leached out l-phenyl-S-mercaptotetrazole present in the developer solution would change the s ensitometric properties of subsequently processed coatings. This is due to the fact that in a processing machine phenyl mercaptotetrazole gradually builds up in concentration until the entire bath must be replaced or addendum must be added to account for increased phenyl mercaptotetrazole concentrations. Accordingly, it is desirable to provide a material which satisfactorily controls speed in processing without changing any of the desired sensitometric characteristics of the coatings during machine processing.

The use of l-phenyl-5-mercaptotetrazole in a photographic emulsion is well known as described, for example, in U.S. Pat. No. 2,403,927 of Kendall et'al. issued in 1946. The use of related compounds is also known, such as described in U.S. Pat. No. 3,266,897 of Kennard et al. issued Aug. 16, 1966, and U.S. Pat. No.

3,295,976 of Abbott and Salminen issued Jan. 3, 1967..

U.S. Pat. No. 3,295,976 of Abbott and Salminen issued Jan. 3, 1967, describes the method of selectively controlling over-development of a multi-layer photo graphic element by a negative developer in a high temperature color process by negative development of this element in the presence of a l-(amidophenyl)-5-mercaptotetrazole. There is no disclosure in these patents, however, of the high contrast elements having the particular silver halide emulsions employed in the graphic arts. Moreover there is no disclosure in this patent of use of l-(amidophenyl)-5 mercaptotetrazole in a high contrast photographic element.

It is also known to use l-(amidophenyl)-5-mercaptotetrazoles as antifoggants in photographic silver halide emulsions which have fogged internal image silver halide grains and unfogged surface latent image silver halide grains as disclosed in French Pat. No. 1,492,] 32 of Kodak. This emulsion, however, has not been employed in high contrast photographic elements utilized in the graphic arts for producing line and halftone dot reproductions.

Accordingly, there is a need for a high contrast photographic element and process which avoids the problems resulting from leaching out of l-phenyl-S- mercaptotetrazole in continuous transport processing machines.

An object of the invention accordingly is to provide a high contrast photographic element containing a lphenyl-S-mercaptotetrazole compound which does not significantly diffuse into processing solutions during machine processing thereby causing undesired sensitometric properties.

Another object is to provide a high contrast photographic emulsion, suitable for use in the graphic arts, which contains a non-diffusing l-phenyl-5-mercaptotetrazole compound.

A further object is to provide a process, especially a continuous transport process, which is suitable for developing an image in a high contrast photographic element as described.

SUMMARY or THE INVENTION graphic emulsion. In another embodiment there is provided a high contrast photographic emulsion containing a l-(amidophenyl)-5-mercaptotetrazole. In yet another embodiment, a continuous process is provided for processing a lith element in one continuous motion by transporting it into, through and out of at least one processing solution in the manner shown, for example, in U.S. Pat. No. 3,025,779 of Russell and Kunz issued Mar. 20, i962; U.S. Pat. No. 3,078,024 of Sardeson issued Feb. 19, I963; U.S. Pat. No. 3,l22,086 of Fitch issued Feb. 25, i964; U.S. Pat. No. 3,149,551 ofCramer issued Sept, 22, .1964; U.S. Pat. No. 3,l56,l73 of Meyer issued Nov. 10, l963; and U.S. Pat. No. 3,224,356 of Fleisher and Hixon issued Feb. 21, 1965; wherein said element is developed in a liquid developer comprising a silver halide developingagent and a carbonyl bisultite-amine condensation product. Such an element and process provides improved speed. control without undesired change of sensitometric characteristics.

DESCRIPTION OFYTHE PREFERRED EMBODIMENTS undesired change of sensitometric characteristics is suitable according to the invention. An especially preferred group of mercaptotetrazoles are the l- (amidophenyl)-5-mercaptotetrazole represented by the formula: v

NHX

methylphenyl and butylphenyl and aralkyl, such as tolyl and xylyl; The hydrocarbon radical can contain various substituent groups such as alkoxy, e.g., containing one to five carbon atoms such as methoxy, ethoxy, propoxy, butoxy and pentoxy, phenoxy, halogen, cyano, nitro,

amino, sulfo, sulfamyl, substituted sulfamyl, sulfonylphenyl, sulfonylalkyl, sulfonamidoalkyl, ,sul-

fonamidophenyl, carboxylic acid, carboxylate, carbamyl, carbamylphenyl, carbamylalkyl, carbonylalkyl, carbonylphenyl and similar groups.

Suitable 'l-(amidophenyl) 5-mercaptotetrazoles include:

l-( 3-caproamidopheny! )-5-mercaptotetrazole, l-( 3-pelargonamidophenyl )-5-mercaptotetrazole,

l-[3-(alpha-2,4 di-t-amylphenoxy)acetamidophenyll-S-mercaptotetrazole, l-( 3-methylsulfonainidophenyl )-5-mercaptotetrazole, l-( 3-p toluenesulfonamidophenyl )-5-mercaptotetrazole, and l-( 3-acetamidophenyl )5-mercaptotetrazole. l-(amidophenyl )-5-rnercaptotetrazoles employed according to the invention can be prepared by methods known in the art such as, for example, by reaction of a corresponding I l-(aminophenyl)-5 mercaptotetrazole hydrochloride with an acid chloride of the desired amido compound. This is disclosed, for example, in U.S. Pat. No. 3,295,976 of Abbott and Salminen issued Jan. 3, I967.

The concentration of l-(amidophenyl)-5-mercaptotetrazole which is suitable for providing desired dot quality without. loss in speed or other desired sensitometric properties, is subject to wide variation. In a photographic emulsion layer or a layer contiguous thereto, a l-(amidophenyl)-5-mercaptotetrazole concentration of about 5 to about 275 milligrams, e.g., about l0 to about 250 milligrams per mole of silver present is suitable.

Any suitable method can be employed for incorporating the described mercaptotetrazole compounds in a photographic emulsion or layer contiguousthereto, such as mixing the described compound in a coating composition prior to the coating on a support/Any method and/or means commonly employed for incorporating addenda into photographic layers can be employed according to the invention.

The developing agents,which can be employed in processing the described photographic elements of the invention can be any of those commonly employedin. the graphic arts. Useful silver halide developing agents, forexample, include the dihydroxy benzenes such as hydroquinone; chlorohydroquinone; bromohydroquinone; 2,3-dichlorohydroquinone; 2,5-dimethylhydroquinone; 2,3-dibromohydroquinone; 1,4- dihydroxy-2-acetophenone-2,S-dimethylhydroquinone; hydroquinone; 2,5-dibenzoylaminohydroquinone; 2,5- diacetaminohydroquinone; etc. Esters of such compounds, -for example, formates and acetates, can also be employed. These developing agents can be used alone or in any combination and can be employed in any concentration which is effective for development.

A suitable concentration for the developing agent is about 0.05 to about 0.50 mole per liter of developer composition and is typically from 0.10v to about 0.30 mole per liter of developer composition.

Development activators, typically alkaline activators, are employed in the developer composition employed for processing elements of the invention. These include any of the inorganic and/or organic alkahes employed in photographic processing solutions, such as alkali metal carbonates and hydroxides, for example,

2,5-diethylhydroquinone; I 2,5 -di-p-phenethylsodium hydroxide, lithium hydroxide, and potassium hydroxide, sodium carbonate, and potassium carbonate. Inorganic alkaline activators can also be employed, such as amino alkanols, for example, amino propanol, amino ethanol, diethylamine, triethylamine, iminodiethanol, etc. Any suitable concentration of development activator can be employed which provides the desired image based on the described photographic element. A concentration is employed which typically provides a developer composition having a pH well above 7, such as about 9 to about 13.

The developer compositions employed for processing the described photographic elements can also contain carbonyl bisulflte-amine condensation products, preferably formaldehyde bisulfite-amine condensation products, such as sodium-2-hydroxyethylaminoethane sulfonate; sodium-2-hydroxypropylaminomethane sulfonate; sodium-1,1-dimethyl- 2-hydroxyethylaminomethane sulfonate; sodium-1,1- bis-(hydroxymethyl)ethylaminomethane sulfonate; sodium-tris(hydroxymethyl)methylaminomethane sulfonate; sodium-3-hydroxypropylaminomethane sulfonate; sodium-bis(2-hydroxyethyl)aminomethane sulfonate; sodium-N,N-bis[2-( l-hydroxy)propyl]aminomethane sulfonate; sodium-N- isopropyl-N-( 2-hydroxyethyl)-aminomethane sulfonate; sodium-N-ethyl-N-(2-hydroxyethyl)- aminomethane sulfonate; and sodium-N-methyl-N-(Z- hydroxyethyl)-aminomethane sulfonate. The carbonyl bisulfiteamine condensation products can be used alone or in a combination and can be employed in any concentration which is effective to provide a low level of sulfite ion in the developer composition. A suitable concentration for the carbonyl bisulfiteamine condensation product is about 0.1 to about 1.0 mole per liter of liquid developer composition and is preferably about 0.25 to about 0.50 mole per liter of liquid developer composition.

The high contrast photographic elements described according to the invention comprise a support bearing a photographic silver halide emulsion layer in which the halide comprises at least about 50 mole percent chloride. The photographic emulsions employed ac cording to the invention are lith emulsions. Such emulsions develop to very high contrast when developed in an infectious developer. (See J.A.C. Yule Formaldehyde-Hydroquinone Developers and Infectious Development, Jour. of the Frank. lnst., Vol. 239, No. 3, March, 1945.) A lith emulsion is typically a high contrast photographic silver halide emulsion in which the halide comprises at least 50 mole percent chloride and less than 5 mole iodide, the remainder being bro mide, said emulsion when exposed on a sensitometer and developed for 2 minutes in Kodak D-85 Developer at C. having a gamma of at least 4 measured between a density of 0.3 and 3.0.

Preferably the halide in the described photographic silver halide emulsion comprises a higher concentration than about 50 percent chloride, such as at least about 85 mole percent chloride and typically at least about 90 mole percent chloride, the balance, if any, being, for example, bromide. These emulsions when exposed on a sensitometer and processed in 1 9'4 minutes through an amine developer system such as described in copending application Ser. No. 661,532, entitled,

Photographic Developer Composition Containing Carbonyl Bisulfite Amine Condensation Product and Free Amine", filed Aug. 18, 1967 now U.S. Pat. No. 3,573,914, will have a contrast of at least about 6. Such preferred emulsions provide particularly good results in high contrast photographic elements and good dot quality. The halide of the photographic silver halide emulsion can also contain a small amount of iodide such as less than about 5 mole percent than is desired. Silver halide emulsions in which the halide comprises 100 mole percent chloride have also been found to be useful.

Other photographic elements containing lith emulsions comprising about 85 mole percent silver chloride are described in: Henn and Goffe, U.S. Pat. No. 3,030,209, issued Apr. 17, 1962, copending U.S. application Ser. No. 661,530 of Salesin entitled High-Contrast Photographic Elements and Methods for Processing Same, filed Aug. 18, 1967, and copending U.S. application Ser. No. 66l,53l of Milton, entitled High-Contrast Photographic Elements and Methods for Processing Same (Case A), filed Aug. l8, i967 now U.S. Pat. No. 3,600,174.

The photographic silver halide emulsion layers of the high contrast photographic elements described according to the invention and/or layers contiguous thereto can contain any of the commonly employed hydrophilic water-permeable binding materials suitable for this purpose. Suitable materials include, for example, gelatin, colloidal albumin, polyvinyl compounds, cellulose derivatives, acrylamide polymers, etc. Mixtures of such binding agents can also be used. The binding agents for the described layers of the high contrast photographic elements of the invention can also contain dispersed polymerized vinyl compounds, especially those which increase the dimensional stability of photographic materials. Suitable synthetic polymers of this type include, for example, water-insoluble of alkyl acrylates and methacrylates or acrylic acid. Such compounds are described for example, in U.S. Pat. No. 3,142,568 of Nottorf, issued July 28, 1964; U.S. Pat. No. 3,193,386 of White, issued July 6, 1965', U.S. Pat. No. 3,062,674 of Houck, Smith and Yudelson, issued Nov. 6, 1962, and U.S. Pat. No. 3,220,844 of Houck, Smith and Yudelson, issued Nov. 30, 1965. These compounds can also be incorporated into a separate layer of the photographic element. The vinyl polymers are generally employed in concentrations in the range of about 20 to about percent by weight, and most often in concentrations of at least 50 percent by weight, based on the weight of the binding agent.

The described high contrast photographic elements of the invention can contain an overcoat layer, such as a heavy overcoat comprising a water-permeable colloid. While any of the hydrophilic water-permeable binding materials described for the emulsion and/or other layers of the high contrast photographic element can be used in the overcoat layer, gelatin has been found to produce good results. lf desired the overcoat layer can also contain dispersed polymerized vinyl compounds as described.

The described high contrast photographic elements of the invention can contain a photographic halide silver emulsion coated on a wide variety of supports. Hydrophilic colloid layers can be coated on one or both sides of the support if desired. Typical supports include any of those commonly employed in preparing photographic elements for the graphic arts field such as cellulose nitrate film, cellulose ester film, polyvinyl acetal film, polystyrene film, poly(ethylene terephthalate) film and related films and/or resinous supports. Glass, paper and metal supports can also be used. Supports such as paper, which are coated with an alpha-olefin polymer, particularly polymers of alpha-olefins containing two or more carbon atoms, such as polyethylene, polypropylene, ethylene-butene copolymers and the like are suitable.

The photographic silver halide emulsions of the high contrast photographic elements of the invention can be sensitized using any of the well known techniques employed in photographic emulsion production, for example by digesting with naturally active gelatin or various sulfur, selenium, tellurium compounds and/or gold compounds. The emulsions can be sensitized with salts of noble metals of Group VIII of the Periodic Table which have an atomic weight greater than 100.

The photographic emulsions of the invention can also contain other addenda commonly employed in photographic elements used in the graphic arts such as speed increasing addenda and/or addenda for increasing contrast such as quaternary ammonium salts, polyethylene glycols, thioether sensitizers or combinations thereof. It can also contain coating aids such as anionic, nonionic and amphoteric surface active agents and the like. They also contain gelatin plasticizers, antifoggants including organic and inorganic antifoggants as well as hardeners such as aldehyde hardeners including, for example, formaldehyde, mucochloric acid, glutaraldehyde bis(sodium bisulfite), maleic dialdehyde, aziridines, dioxane derivatives and oxpolysaccharides.

The high contrast photographic silver halide emulsions of the invention can be ortho-sensitized or pansensitized with spectral sensitizing dyes. For instance, these emulsions can be spectrally sensitized with merocyanine dyes, hemicyanine dyes and/or dyes useful in sensitizing such emulsions are described for example in U.S. Pat. No. 2,526,632 of Brooker and White, issued Oct. 25, 1950; and U.S. Pat. No. 2,503,776 of Sprague, issued Apr. 11, I950.

Photographic elements according to the invention can be processed employing processing solutions and methods employed in the graphic arts and especially those employed for processing lith emulsions. They are preferably processed, typically after exposure through a contact screen employed in the graphic arts, using a 90 second development time in a Kodalith Roller Transparent 324 Film Processor of the type described in U.S. Pat. No. 3,025,779 of Russell and Kunz, issued Mar. 20, 1962, employing typically a developer having the following composition:

Sodium-bis-( 2-hydroxyethyl)- aminomethane sulfonate" 82.0 grams Sodium sulfite 30.0 grams Boric acid 7.5 grams I-Iydroquinone 22.5 grams Potassium bromide 1.6 grams 2,2'-Iminodiethanol 39.0 grams Water to make 1 liter pH 9.5

Accordingly, another embodiment of the invention comprises in a continuous process for processing an exposed high contrast photographic element comprising a 7,

support coated with a photographic silver halide emulsion wherein said element is processed in one continuous motion by transporting it into, through and out of at least one processing solution, the improvement comprising the combination of:

a. developing said element in a liquid developer composition comprising a silver halide developing agent and a carbonyl bisulfite-amine condensation product,

b. said halide comprises at least about 50 mole percent chloride, and preferably at least mole percent chloride, and

c. said element has a coating containing a l-phenyl- S-mercaptotetrazole compound having the property of being non-diffusible in a photographic emulsion. Such a process wherein the l-phenyl-5-mercaptotetrazole compound is a l-(amidophenyl)-5-mercaptotetrazole, as described, is preferred. A process of the invention is also preferred wherein the developer solution is an aqueous solution containing a hydroquinone developing agent in a concentration of about 0.05 to about 0.50 mole per liter of solution and containing a formaldehyde bisulfite-amine condensation product present in a concentration of about 0.10 to about 1.0 mole per liter of developer solution.

Typically the processed element of the invention, as employed in the graphic arts field, consists of a pattern of dots, areas commonly referred to as shadow dots and areas known as high-light areas. Intermediate between the two extremes of areas referred to as shadow dots and areas known as high-light areas are areas of varying size. The common method in the graphic arts for measuring the quality of reproduction of a photographic element is to examine the dot areas. The quality of dot can be expressed on any convenient scale, but for the purposes of the invention the following scale can be employed to refer to a quality of dot: a grade scale between 1 and 9 is employed wherein 9 is excellent and l is extremely poor with varying degrees of quality between these two points. This scale is employed herein to designate the quality ofimage.

The following examples are included for a further understanding of the invention.

EXAMPLEI A fine-grain silver chlorobromoiodide gelatino emulsion containing mole percent chloride, 9 mole per cent bromide and 1 mole percent chloride is chemically sensitized with sulfur and gold compounds and coated on a polyethylene terephthalate support. The emulsion is applied to the support at the rate of 456 milligrams of silver per square foot, 296 milligrams of gelatin per square foot and 296 milligrams per square foot of alkyl acrylate polymer as described in U.S. application Ser. No. 525,272 filed Dec. 20, 1965 of D. A. Smith now U.S. Pat. No. 3,459,798. A gelatin overcoat is coated on the resulting emulsion layer at 82.6 milligrams per square foot. The resulting product is designated as Product A and employed as a control.

Identical coatings are made with the exception that l-( 3-acetamidophenyl )-5-mercaptote trazole also known as AcPMT, is added to separate portions of the described emulsion at the rate respectively of 5, 25 and 125 milligrams of l-(3-acetamidophenyl)-5-mercaptotetrazole-per mole of silver present. These products mercaptotetrazole in place of l-(3-acetamidophenyl)-5 -mercaptotetrazole per mole of silver.

are designated, respectively, as Product B, Product C G. Product G contains 125 milligrams of l-(3- and Product D. acetamidophenyl)--mercaptotetrazole per mole of The resulting dried coatings are exposed using tung- 5 silver. sten illumination to a step wedge through a magenta H. Product H contains 250 milligrams of 1-(3- contact screen. The element are then processed using a acetamidophenyl)-5-mercaptotetrazole per mole of 90 second development time in a Kodalith Roller ilvr- Transport 324 Film Processor as described in 11.5. Pat. 500 milliliter portions of the developer solution No. 3,025,799 of Russell and Kunz, issued Mar. 20, described in Example 1 are employed. Fifteen unex- 1962 employing the following developer: posed 4 X inch sheets (4.15 square feet) of each of the described Products E, F, G and H are passed d H y y y through the described developer portions. The result- Sulfonatei 23:8 22:: ing developer is designated as Developer A. Then 30 Boric acid 7.5 grams unexposed 4 X 10 inch sheets (8.30 square feet) of gydmfiuinone grams Products E, F, G, and H are passed through separate otassrum bromide 1.6 grams zyzniminodiethanoi 300 grams 500 milliliter portions of the developer composition set J" make out in Example 1. The resulting developer is designated Sodiu in formaldehyde bisulfite and 2,2'- iminodiethanol can be used as Developer B" to form thiscompound insitu. A control, as described in Example 1, containing neither phenylmercaptotetrazole or l-( 3- The resulting image consists of a pattern of dot areas acetamidophehyll's'mercapwtetrazole is Prepared commonly referred to in the art as shadow dots and and exposed as Set out in Example The resulting areas known as high-light areas. Intermediate between 25 is Processed for l 84 minutes w Seconds, at these two extremes are areas of varying size including a 2700 in each of the resulting developer Solutions, so-called middletone area. The letters H, M and S each of Developer A and Developer The results of described herein refer respectively to high-light, these tests are Q P to the Control Processed in a iddl d h d 1 w fresh developing solution whose speed is assigned 100. The results obtained are et out i Table l, Th l The results are also compared to the control processed tive speed, effective contrast and dot quality are given in a fr sh d veloping Solution to which is added 8.72 for varying development time. Development time is milligrams of l-(3-acetamidophenyl)-5-mercapvaried between l /2 minutes, i.e. 90 seconds, and 2 totetrazole per 500 milliliters of developing solution. minutes, i.e., 135 seconds. (8.72 milligrams of l-(3-acetamidophenyl)-5-mercap- TABLE 1 Dot quality AcPMT Relative speed Effective contrast rngJAg 1% 1 4' Product mole 1% 1% 2 2% 1% 1% 2 2% M HMS M M A (control) None 100 141 155 166-' 7.7 8.5 9.0 0.0 7 484 8 8 B 5 100 132 138 149 7.7 8.8 9.0 0.0 8 484 8 EXAMPLE 2 This is a comparative example illustrating advantages of the invention.

Four photographic elements are prepared as set out in Example 1 and are designated respectively as Products E, F, G, and H. These products contain the following differences from the products described in Example 1:

E. Product E contains no l-( 3-acetarnidophenyl)-5- mercaptotetrazole or l-phenyl-5-mercaptotetrazole.

F. Product F contains 125 milligrams of l-phenyl-S- totetrazole is calculated as the approximate amount that is leached out under equilibrium conditions for processing coatings containing milligrams of 1-(3- acetamidophenyl)-5-mercaptotetrazole per mole of silver).

The following Table 11 lists the results obtained. Table II lists the relative speeds of the control coating processed in developing solutions through which were passed the described 4 X 10 inch sheets of Products E, F, G and H.

TABLE II prior art invention invention Control Prod. F Prod. G Fred. H Prod. E 125 mg. 125 mg. 250 mg. None PMT/mole AcPMT/ AcPMT/ mole mole Developer A 102 94 101 96 Developer B 94 53 99 91 The relative speed of the control coating when employing a fresh developer containing 8.72 milligrams of l-(B-acetamidophenyl)-5-mercaptotetrazole is 76, whereas the relative speed of a control containing no mercaptotetrazole compound is 100.

A comparison of the relative speeds of each of the coatings listed in Table II illustrates that:

a. l-( 3-acetamidophenyl)-5-mercaptotetrazole, when added to the described developing solution, provides a speed loss for coatings processed therein;

b. photographic elements according to the invention containing l-(3-acetamidophenyl)-5-mercaptotetrazole provide no speed loss, thus indicating that the described mercaptotetrazole of the invention does not leach out of the described coating; and

c. there is a speed loss for the control processed in a developer solution in which coatings containing 1- phenyl--mercaptotetrazole are previously processed. This indicates that, surprisingly, by employing a photographic element of the invention the disadvantageous sensitometric effects caused by employing a photographic element containing l-phenyl-5-mercaptotetrazole are avoided.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will beunderstood that variations and modifications can be effected within the spirit and scope of the invention.

1 claim:

l. A high contrast photographic element comprising a support having thereon a photographic lith type silver halide emulsion wherein said halide comprises at least about 85 mole percent chloride, said element containing a l-(amidophenyl)-5-mercaptotetrazole, said mercaptotetrazole being nondiffusible in a photographic emulsion.

2. A high contrast photographic element as in claim 1, wherein said l-(amidophenyl)-5-mercaptotetrazole compound is present in a coating contiguous to said photographic silver halide emulsion.

3. A high contrast photographic element as in claim 1 wherein said mercaptotetrazole is a l-(3- acetamidophenyl)-5-mercaptotetrazole.

4. A high contrast photographic element as in claim 1 containing about 5 to about 250 milligrams of said 1- (amidophenyl)-5-mercaptotetrazole per mole of silver present in said photographic silver halide emulsion.

5. A high contrast photographic lith silver halide emulsion, said halide comprising at least about 85 mole percent chloride, containing about 5 to about 250 milligrams of a -(amidophenyl)-l-(aminophenyl)-5-mer captotetrazole per mole of silver, said mercaptotetrazole being nondiffusible in a photographic emulsion.

6. A high contrast photographic lith type silver halide emulsion as in claim 5 wherein said halide comprises I about 90 mole percent chloride, about I mole percent iodide and about 9 mole percent bromide.

7. In a continuous process for processing an exposed high contrast photographic element comprising a support coated with a photographic lith type silver halide emulsion, said process comprising the steps of transporting said element in one continuous motion into, through and out of at least one processing solution comprising a liquid developer composition, the improvement comprising the combination of:

a. said developer composition comprising a silver halide developing agent and a carbonyl bisulfiteamine condensation product,

b. said halide comprising at least about mole percent chloride, and c. said element having a coating containing a l- (amidophenyl)-5-mercaptotetrazole being nondiffusible in a photographic emulsion.

8. A process as in claim 7 wherein said S'mercaptotetrazole is l-(3-acetamidophenyl)-5-mercaptotetrazole.

9. A process as in claim 7 wherein said developing agent is a dihydroxybenzene developing agent and said carbonyl bisulfite-amine condensation product is a formaldehyde bisulfite-amine condensation product.

10. The process of claim 7 wherein said developer solution is an aqueous solution, said developing agent is hydroquinone present in said solution in a concentration of about 0.05 to about 0.50 mole per liter of developer solution and said carbonyl bisulfite-amine condensation product is a formaldehyde bisulfiteamine condensation product present in a concentration of about 0.10 to about 1.0 mole per liter of developer solution.

11. The process of claim 7 wherein said photographic element is transported by rollers.

Claims

2. A high contrast photographic element as in claim 1, wherein said 1-(amidophenyl)-5-mercaptotetrazole compound is present in a coating contiguous to said photographic silver halide emulsion.
3. A high contrast photographic element as in claim 1 wherein said mercaptotetrazole is a 1-(3-acetamidophenyl)-5-mercaptotetrazole.
4. A high contrast photographic element as in claim 1 containing about 5 to about 250 milligrams of said 1-(amidophenyl)-5-mercaptotetrazole pEr mole of silver present in said photographic silver halide emulsion.
5. A high contrast photographic lith silver halide emulsion, said halide comprising at least about 85 mole percent chloride, containing about 5 to about 250 milligrams of a -(amidophenyl)-1-(aminophenyl)-5-mercaptotetrazole per mole of silver, said mercaptotetrazole being nondiffusible in a photographic emulsion.
6. A high contrast photographic lith type silver halide emulsion as in claim 5 wherein said halide comprises about 90 mole percent chloride, about 1 mole percent iodide and about 9 mole percent bromide.
7. In a continuous process for processing an exposed high contrast photographic element comprising a support coated with a photographic lith type silver halide emulsion, said process comprising the steps of transporting said element in one continuous motion into, through and out of at least one processing solution comprising a liquid developer composition, the improvement comprising the combination of: a. said developer composition comprising a silver halide developing agent and a carbonyl bisulfite-amine condensation product, b. said halide comprising at least about 85 mole percent chloride, and c. said element having a coating containing a 1-(amidophenyl)-5-mercaptotetrazole being nondiffusible in a photographic emulsion.
8. A process as in claim 7 wherein said 5-mercaptotetrazole is 1-(3-acetamidophenyl)-5-mercaptotetrazole.
9. A process as in claim 7 wherein said developing agent is a dihydroxybenzene developing agent and said carbonyl bisulfite-amine condensation product is a formaldehyde bisulfite-amine condensation product.
10. The process of claim 7 wherein said developer solution is an aqueous solution, said developing agent is hydroquinone present in said solution in a concentration of about 0.05 to about 0.50 mole per liter of developer solution and said carbonyl bisulfite-amine condensation product is a formaldehyde bisulfite-amine condensation product present in a concentration of about 0.10 to about 1.0 mole per liter of developer solution.
11. The process of claim 7 wherein said photographic element is transported by rollers.