US3816136A - Photographic element and process of developing - Google Patents

Abstract

A radiation-sensitive element containing incorporated processing chemicals is processed in a fluid activator which does not cause the processed element to be tacky. The element includes a fluidimpermeable support having thereon a radiation-sensitive material which is activated by the fluid developing agent and results in a processed element which is dry to the touch and is substantially free from tackiness when removed from contact with the fluid activator. If a stabilizer precursor is incorporated in the element, the image is stable to further exposure to raditaion.

Description

United States Patent 1191 1111 3,816,136

Goffe et al. June 11 1974 PHOTOGRAPHIC ELEMENT AND PROCESS 3,615.529 10/1971 Tajima 96/95 OF DEVELOPING 3.647.460 3/1972 Hofman 1 96/61 R 3,664,835 5/[972 Youngquist.... 96/61 R [75] Inventors: Cha les G c p 3,666,457 5/1972 Youngquist 96/61 R Richard W. Henn, Rochester; Paul Swm, penfield Of Primary Examiner-Ronald H. Smith [73] Assigneez Eastman Kodak Company, Assistant Examiner-did. F. Kelley Rochester Attorney, Agent, or Fzrm-Henry E. Byers [22] Filed: July 17, 1972 [57] ABSTRACT PP N03 272,535 A radiation-sensitive element containing incorporated 1 processing chemicals is processed in a fluid activator 52 US. Cl. 915/66 R, 96/50 R, 96/67, whih does not cause the processed element to be 9 95 tacky. The element includes a fluid-impermeable sup- [51] Int. Cl. G03c 5/30, 003 5/26 603 1/0 port having thereon a radiation-sensitive material 58 Field 61 Search 96/95, 67, '50 PL, 50,61, which is activated y the fluid developing agent and 9 results in a processed element which is dry to the touch and is substantially free from tackiness when re- 5 References Cited moved from contact with the fluid activator. If a stabi- UNITED STATES PATENTS lizer precursor is incorporated in the element, the

image is stable to further exposure to raditaion. 3,468,664 9/l969 Stewart 96/95 3,591,379 7/1971 Plakunov 96/50 26 Claims, 1 Drawing Figure 1 PHOTOGRAPHIC ELEMENT AND PROCESS OF DEVELOPING BACKGROUND OF THE INVENTION This invention relates to a method of processing radiation-sensitive elements containing incorporated processing chemicals by contacting the element with a liquid activator which results in an element which'is substantially dry' to the touch and free from tackiness when contacted against a similar surface. It also relates to photographic elements which comprise a waterimpermeable support having thereon a radiationsensitive material; such as, silver halide, a developing agent and, preferably, a stabilizer precursor which may be dispersed in a hydrophilic binder having thereon a hydrophobic overcoat; The element is penneable to ammonia or amine vapor or to an amine contained in an aqueous solution or other solvent that leaves the surface substantially dry and tack free.

Photographic elements have conventionally been processed using liquid solutions which have contained processing chemicals or by immersing an element in a liquid activator solution. In particular, silver halide emulsions dispersed in gelatin or a similar hydrophilic vehicle, have absorbed water resulting in a swelling of the binding material and generally tacky or sticky surfaces. This has inhibited handling of the wet elements, has required anextensive drying treatment, for example, withhot air, and has presented storage problems, and the like. In order to avoid these types of problems, many so-called dry processes have been proposed, including those which require heat to initiate or provide the activation necessary to process an exposed element. For instance, Jacobs, U.S. Pat. No. 3,248,219, issued Apr. 26, I966, discloses a photographic element for dry processing which comprises a support, a silver halide emulsion, and on the same support, a'dry developing agent which requires the presence of water to become active, and, in a separate layer, a stabilizing agent which is activated by the presence of water, having over the element as an overcoat, a sealer layer which may comprise vegetable gum, gum tragacanth, gum arabic, etc. Such overcoats, however, are tacky after immersion in an aqueous amine solution or on contact with ammonia or amine vapor long enough to develop an image in the exposed element. Further, such an element containing the stabilizing agent in a reactive form may cause stabilization prior to exposure and activatron.

Stewart, U.S. Pat. No. 3,468,664, issued Sept. 23, I969, discloses a heat processable photographic element comprising a paper support having thereon a silver halide emulsion layer also containing a developing agent and having a moisture-impervious overcoat; such as, a cellulose ester or synthetic polymer coating or laminate serving to confine moisture to the element during a heat-development step. However, this element will not produce a permanent image without further chemical treatment.

These processes typically require a relatively high level of heat and require supports which will stand this amount of heatas well as certain types of binders and the like.

In certain specialized types of photography, it is desirable to have the element exposed and developed without moving the element after exposure. This is particularly important when used in preparing holographs. A process for processing in place using ammonia or amine vapor for processing a radiation-sensitive element which contains incorporated therein processing chemicals; such as, a developing agent and stabilizer precursor has been described in King, U.S. Pat. application Ser. No. 224,935, filed Feb. 2, 1972 now abandoned. However, in the case of silver halide materials, this element is tacky to the touch so that it is not conveniently handled or stored immediately following processing. Accordingly, there has been a need for a similar product which could be processed in place which would be substantially dry to the touch and free from tackiness after being processed.

SUMMARY OF THE INVENTION An image is obtained in an exposed radiationsensitive silver halide element by a process which in-' volves contacting the element witha fluid activator such as a vapor or liquid activator. The element comprises a support which is substantially impermeable or uneffected by the fluid activator and has thereon a radiation-sensitive silver halide material and a developing agent for the material which is activated by the fluid activator. The processed image side of the element after being removed from contact with the fluid, either by discontinuing the vapor contact or by removing from a solution, is substantially free from tac kiness and appears dry to the touch.

A particularly useful process comprises developing an element comprising a substantially waterimpervious support, having thereon a radiationsensitive layer such as a silver halide emulsion, and a developing agent for the silver halide salt. The binder can be hydrophilic with a hydrophobic overcoat. The overcoat is substantially impervious to water but is pervious to an alkaline fluid activator; such as, for example, ammonia, amine vapors, or to an amine from an aqueous amine solution. The exposed element is processed by contacting with ammonia or an amine vapor or by immersing in an aqueous solution containing an amine. After processing, the surface of the element is substantially dryto the touch and is relatively free from tackiness when contacted against itself. In a preferred embodiment, a stabilizer precursor is also incorporated in the element so that the processed element is stable to exposure to radiation.

In one embodiment, a polyester support hasthereon a silver halide emulsion, a developing agent and a stabilizer precursor incorporated in a gelatin vehicle over which is coated a cellulose acetate layer. The element is immersed in an aqueous solution containing about 50 percent by weight ethanolamine and results in a stabilized element containing a silver image in less than a minute at C.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing:

FIG. 1 illustrates one embodiment of our invention wherein a support a, such as poly(ethylene terephthalate), is coated with a layer b of a silver halide emulsion, developing agent and a stabilizer precursor. A barrier layer c of cellulose acetate is coated over the silver halide emulsion layer b. After exposing to a light image, the exposed element is immersed in an activator bath d comprising an aqueous-ethanolamine solution (50-50 by weight). The activating amine penetrates the barrier layer to cause the developing agent to reduce the exposed silver halide, creating a visible image, and the stabilizer precursor, to stabilize the element against further development of density on further exposure to light.

' As the element is withdrawn from the activating bath d the solution drains from the surface of the element. The surface of the barrier layer c appears dry to the touch and is free from tackiness.

DESCRlPTlON OF THE PREFERRED EMBODIMENTS Vapor processing, such as can be performed according to this invention, is ideally suited for single exposure holographic interferometry. See Principles of Holography" by Howard H. Smith, 1969, John Wiley, N.Y., N.Y. With this method of interferometry it is necessary that the exposed emulsion be in precisely the same position during exposure to the object beam and reference beam and for read-out using the reference beams. The hologram must be struck by the read-out beam in order to see the image at precisely the same angle as during exposure. If the film has to be moved for processing, it is difficult to design a system for registering the film. 1f the film is processed conventionally, but in place, the arrangements for admitting and flushing the various liquid chemicals is complex, costly and 7 slow. Also, with wet processing, the dimensional stability of the emulsion is not good, which is detrimental to single exposure holographic interferometry. Vapor processing is dry, fast and economical and can be performed easily with the emulsion in-place; negligible swelling of the emulsion occurring. Moreover, there is wide latitude in temperature and time; vapor processing can be carried out at about 15C to about 66C to obtain useful images within about l to 180 seconds.

By using the element of our invention, the resulting element is dry to the touch and can be rolled upon itself without stickiness or tackiness, which normally occurs when a gelatin emulsion without an overcoat is vapor processed.

Various photographic salts, especially'photographicsilver salts, can be employed in the elements used in the invention. Those include photographic silver halide, such as silver iodide, silver bromide, silver chloride, as well as mixed halides, such as silver bromoiodide, silver chloroiodide, and the like. Radiation-sensitive silver halides are typically coated in an amount of 1.5 mg. of silver to 50 mg. of silver per square decimeter and preferably about 12 mg. per decimeter.

Developing agents can be incorporated in the photographic element in one or more layers using wellknown techniques in the photographic art. For example, they can be dissolved in a suitable solvent and added or they can be added in the form of a dispersion. Techniques of this type are described, for example, in U.S. Pat. No. 2,322,027 of .lelley et al. issued June 15, 1943 and U.S. Pat. No. 2,801,171 ofFierke et al. issued July 30, 1957. In a preferred embodiment, methyl gallate/1-phenyl-3-pyrazolidone (/1) developer is used.

Suitable silver halide developing agents which can be employed in the practice of the invention include, for example, polyhydroxy benzenes, such as hydroquinone developing agents, e.g. hydroquinone, alkyl substituted hydroquinone such as tertiary butyl hydroquinone, methyl hydroquinone, carboxyalkyl hydroquinones and 4 2,5-dimethylhydroquinone; catechol and pyrogallol; chloro substituted hydroquinones such as chlorohydroquinone or dichlorohydroquinone; alkoxy substituted hydroquinones such as methoxyhydroquinone or ethoxyhydroquinone; aminophenol developing agents such as 2,4-diaminophenols, e.g., 2,4-diamino-6- methylphenol, and methylaminophenols; hydroxyl amines, such as N,N-di(2-ethoxyethyl)-amine; 3- pyrazolidone developing agents, such as lphenyl-3- pyrazolidone, including those described in British Pat. No. 930,572; ascorbic acids, such as d-araboascorbic acid, iminogluco ascorbic acid, isopropylidene ascorbic acid; hydroxytetronic acids, such as phenylhydroxytetronic acid, phenylhydroxy tetronimide; pryimidine developing agents such described by Henn and Carpenter, Photographic Science and Engineering, Vol. 3, pages -139, 1959; reductones as amino hexose reductones disclosed in French Patent 2,065,792; and acyl derivatives of aminophenols, such as described in British Pat. No. 1,045,303. These developing agents can be used alone or in combination.

Particularly useful developing agents include methyl gallate, hydroquinone, gallic acid, (2 ,5- dihydroxyphenyl) acetic acid, 2,5-dihydroxy-pbenzenediacetic acid, 2',3,4'-

trihydroxyacetophenone, 2-isopropyl-4,5,6 trihydroxypyrimidine, 3,6-dihydroxybenzonorbornane, pyrogallol, ascorbic acid, l-phenylB-pyrazolidone and phenyl hydroquinone.

The developing agents can be employed in a wide range of concentrations. Normally, concentrations of about 0.25 to about 4.0 moles per mole of silver of the principal developing agent can be employed. Lesser amounts, such as 0.05 to 0.5 moles of auxiliary developing agents are useful. One mole of developing agent per mole of silver present in the photographic element is often suitable.

The photosensitive elements used in the practice of the invention embodying the hydrophilic binder can contain various hydrophilic colloids alone or in combination as vehicles or binding agents. Suitable materials are typically hydrophilic colloids which are transparent or translucent and include naturally occurring substances such as proteins, for example, gelatin, gelatin derivatives, cellulose derivatives, polysaccharides such as dextrin, gum arabic and the like; and synthetic polymeric substances such as water-soluble polyvinyl compounds like poly-( vinyl pyrrolidone), acrylamide polymers and the like. Particularly useful binding agents are gelatin, including pig gelatin, polyvinyldisulfobenzal and a terpolymer vehicle of N-isopropylacrylamide, 3- methylacrylolyoxypropane-l-sulfonic acid sodium salt, and 2-acetoacetoxyethylmethacrylate.

The stabilizer precursors which may be used in this invention include the compounds of Humphlett et al, U.S. Pat. No. 3,301,678 issued Jan. 31, 1967. These compounds can be represented by the following formulas:

Formula I Formula IV R" R'CH-CH RILM\RH In the above formulas: R, R, R and R are each lower alkylene radicals having 1 to 5 carbon atoms including methylene, ethylene, propylene, butylene, isobutylene, and amylene, R, R, R, R and R are each hydrogen atoms, lower alkyl radicals having 1 to 5 carbon atoms or aryl radicals having 6 to 12 carbon atoms such as phenyl and naphthyl and substituted aryl as described below for R and R. R and R are each aryl radicals having 6 to 12 carbon atoms such as phenyl and naphthyl and typically include substituted aryl radicals as illustrated by the radical having the formula:

X is an anion or acid residue such as chloride, bromide, nitrate, trichloroacetate, perchlorate, formate, acetate, aminoacetate, p-toluene sulfonate, sulfonate, trifluoroacetate, chloroacetate, ethyl sulfate or the like. A is a hydroxy radical or a radical having the formula wherein R'", R, R, R. R and R are each hydrogen atoms, lower alkyl radicals having I to 5 carbon atoms or an aryl radical as described for R and R, and

X is anaasa'as aaqibeaasavauaaz'aa each by cals, and more generally tertiary amino radicals such as morpholino, piperidino, pyrrolidino, and dialkyl amino wherein the alkyl moiety has 1 to 5 carbon atoms.

Compounds of Formula II] and fonnula lV above are commonly prepared as salts such as hydrochloride salts to facilitate purifications and to increase'their water solubility to facilitate incorporation in photographic layers. Suitable compounds within the scope of these generic structures include Z-hydroxyethylisothiuronium chloride 2-hydroxyethyliosthiuronium trichloroacetate isothiureidoacetic acid 2-isothiureidopropionic acid B-( 2-morpholinoethylthio )-B-phenylpropiophenone hydrochloride 2-ethylaminoethylisothiuronium chloride 2-hydroxypropylisothiuronium trichloroacetate a-Nitrilo-B 2-morpholinoethylthio )propionitrile hydrochloride a-Carbethoxy-B-(2-morpholinoethylthio)-B- phenylpropionitrile hydrochloride Ethyl oz-amido-B-( 2-morpholinoethylthio)-B- phenylpropionate hydrochloride 2-hydroxyethyl- 1 -methylisothiuronium chloride Z-hydroxyethyll -phenylisothiuronium chloride l-phenyl-2-isothiureidoacetic acid Other suitable stabilizer precursors include those of US. Pat. No. 3,220,839Herz and Kalenda. These include isothiourea derivatives represented by the general structures:

R, R R, R", R R and R can be hydrogen atoms, hydrocarbon radicals such as aryl radicals having 6 to 12 carbon atoms as illustrated by phenyl radicals, alkylsubstituted phenyl and alkyl radicals and substituted alkyl radicals. R and R can also be acyl radicals having the formula:

Ril-

wherein R isan alkyl radical having 1 to 5 carbon atoms. R and R together can be the necessary atoms to form a heterocyclic ring or preferably they can be the necessary carbon and hydrogen atoms to form an alkylene radical linking both adjacent nitrogen atoms to form a cyclic nucleus as illustrated by the following moiety wherein R is an alkylene radical having 2 to 20 carbon atoms, more generally 2 to 4 carbon atoms.

I if

wherein R can be an acylradical having 2 to 6 carbon atoms in addition to those substituents described above for R The letter n'can be an integer. of at least I, and generally 1 to 10, and preferably 1 to 3. The letter Y can be a carboxyl radical, a sulfonate radical, a hydroxyl radical or an amino radical, including substituted amino radicals, of the formula wherein R is a hydrogen atom or an alkyl radical, and wherein R is a hydrogen atom, an alkyl radical or an acyl radical, their salts having the formula or a r'norpholino radical. Typical alkyl and alkylene radicals referred to above have 1 to 20 carbon atoms and more generally I to 4 carbon atoms. Illustrative alkyl radicals include methyl, ethyl, isopropyl, n-butyl, 2-ethylhexyl, n-decyl, stearyl, n-eicosyl and the like radicals. Alkylene radicals analogous to such alkyl radicals are suitable R substituents. Suitable compounds within the scope of this structure include, for example, 2-Sthiuronium ethane sulfonate:

3-S-thiuronium propane sulfonate:

4-Sthiuronium butane sulfonate:

3-S-thiuroniuml -methyl-propanesulfonate A useful class of S-carbamoyl silver salt stabilizer wherein R and R are each selected from the group consisting of hydrogen, alkyl, especially alkyl containing 1 to 5 carbon atoms such as methyl, ethyl, propyl, butyl andpentyl, aryl, e.g. phenyl and tolyl; and S-R is a sulfur containing moiety which has the property of complexing with photosensitive silver halide in the presence of heat or alkali. The alkyl and aryl radicals and the sulfur containing moiety can contain substituent groups which do not adversely effect stabilizing action or desired properties of the described silver salt stabilizer precursor or the photosensitive material in which the precursors are employed. Typical examples of substituent groups which do not adversely affect the activity of the stabilizer precursor include methyl, ethyl, propyl. isopropyl, tertiary butyl and n-butyl. The described compounds also include salts of such compounds, such as amine salts, which do not adversely affeet the activity of the stabilizer precursor. The described sulfur-containing moiety which has the property of complexing with photosensitive silver halide in the presence of heat and/or alkali, is a moiety which will cleave or be released from the described carbamoyl stabilizer precursor at elevated temperatures or in the presence of alkali such as ammonia or amine vapors and complexes or combines with a photosensitive silver salt such as photosensitive silver halide in unexposed areas of a photosensitive silver salt material, such as a photosensitive silver halide emulsion, forming a mercaptide compound which is more stable to light, atmospheric conditions and ambient temperatures than the photosensitive silver salt.

Especially useful S-carbamoyl silver salt stabilizer precursors include:

S-ethylcarbamoyl-2-mercaptoisobutyric acid, dicyclohexylamine salt, S-ethylcarbamoyl-2-mercaptoethylamine, p-toluene sulfonic acid salt, 3-( Ethylcarbamoylthio )propanesulfonic guanidinium salt, and S-ethylcarbamoyl-N-acetyl-Z-mercaptoethylamine. The described S-carbamoyl silver salt stabilizer precursors can be prepared by procedures known in the art. For instance, procedures described in St. Guttmann, Helv. Chem. Acta, 40:83 (1966) are suitable.

in one embodiment the above compounds which contain a sulfonate radical and form so-called inner acid salts are preferred stabilizer precursors. lnner acid salts as employed herein are disclosed in Herz and Kalenda US. Pat. No. 3,220,839 issued Nov. 30, 1965.

acid,

The stabilizer precursors employed in this invention are generally stable and substantially inert in photographic silver halide emulsions in acidic or neutral media and under temperatures that prevail during conventional storage and use of the photographic prod- UCtS.

The stabilizer precursor can be incorporated in photographic emulsions or layers of photographic elements using any of the techniques commonly used in the photographic art. For example, it can be dissolved in a suitable solvent and added as such or it may be added in the form of a dispersion. Techniques which may be employed in adding the precursor to photographic eleuents which are miscible with components employed may be utilized to aid in the addition.

The stabilizer precursors are utilized in theelements used in this invention in concentrations of generally about 0.01 mole to about moles per mole of silver salt and preferably from about 0.4 mole to about 2.0 mole per mole of silver halide.

The radiation-sensitive layers and other layers of an element employed in the practice of the invention and described herein can be coated on a wide'variety of impervious supports. Typical supports include cellulose nitrate film, cellulose ester film, poly(vinylacetal) film, polystyrene film, poly(ethylene terephthalate) film, polycarbonate film and related films or resinous materials, as well as glass, metal and the like. Typically, a flexible support is employed; for instance, paper coated on both sides with polymeric material; such as, an alpha olefin containing 2 to l0 carbon atoms; for example, polyethylene, polypropylene, polybutylene copolymers and the like. 1

In a preferred embodiment, a photographic element in which the support has thereon a silver halide emulsion, a silver halide developing agent and a stabilizer precursor, is overcoated with a film-forming material in an amount of 2 to 50 milligrams per square decimeter. The film-forming material is substantially impervious to water but is permeable to ammonia, amine vapors and to liquid amines. These materials are known as elastomeric materials and are materials which can be dissolved in an organic liquid and which will give a continuous film when the solvent is evaporated or any elastomeric material which can be suspended in water or an organic liquid and which will give a continuous film when the suspending medium is evaporated.

Preferably, the resulting element having the elasto mer as an'overcoat is dry to the touch and substantially free from tack after processing as determined by contacting witha similar surface. Exposed 35mm strips are contacted with an activator fluid to give an image having a density (D of at least 0.5, withdrawn through squeegees if a liquid is employed and pressed into contact with an unprocessed piece of the same film between rollers having a pressureof about pounds total pressure on the rollers. After a contact time of 50 minutes, they are stripped apart using a spring gauge to measure the force needed for stripping. In a preferred embodiment, the force is from O to about one/half ounce. When the overcoated element of the invention is used with ammonia or amine vapor processing, similar freedom from tackiness is obtained.

The elastomeric materials can be varied widely but include the following, for example;

l. Butadiene polymers: copolymers of butadiene with acrylonitrile, styrene and esters of acrylic acid.

2. Polyvinyl acetals: acetals of polyvinyl acohol made with higher aldehydes;'such as, butyraldehyde, 2-

ethylhexaldehyde and heptaldehyde.

3. Vinyl polymers: homopolymers and copolymers; such as, those made from vinyl chloride, esters of acrylic acid, esters of metha'crylic acid, and vinyl acetate.

4. Chloroprene: polymers and copolymers of chloroprene with acrylonitrile, styrene and esters of acrylic esters.

5. Diisocyanate-linked condensation elastomers: diisocyanates; such as, toluene diisocyanate reacted with relatively short linear polyester molecules to form polyurethanes and polymers produced from the reaction of diisocyanates with diamines; such as 3,3 (2,2-dimethyltrimethylenedioxy) bis propyl amine.

6. Cellulosic esters: cellulose esters; such as, cellulose acetate, cellulose propionate and cellulose acetate butyrate.

7. Cellulosic ethers: cellulose ethers; such as, ethyl cellulose and methyl cellulose.

8. Silicones: polysiloxanes having the following general formula:

wherein x is an integer from 6 to 40, and R is a methyl or a phenyl radical so chosen that both radicals on any given silicone atom are identical and the molar ratio of methyl to phenyl radicals varies from 4:1 to 1:4. Higher molecular weight siloxanes are operable for use in this invention; Organosilicone block polymers prepared by reacting a polypropylene oxide-polyethylene oxide block polymer with the following general structure:

wherein a and b are positive integers, M is a polyethyleneoxy chain constituting approximately 10-70 percent by weight of [(M)a(N)b]y N is a polypropyleneoxy chain having a molecular weight between approximately 800 and 3,000, and wherein x, y and n are positive integers as shown in Table A.

TABLE A COMPOUND RATIO n PERCENT yzx SILICON A 2:1 7 9.3 B 2:] 6 7.0 C 4:1 3 8.0 D 2:1 7 12.0. E 2: l 8 l3.0 F l.5:l l-8 6.3 G l:l.5 2 1.4 H 1:1.5 1 .62 l 1:] l .2

When the film-forming elastomer is used as a suspension, water or an organic liquid may be used as the suspending medium. When the elastomer is used as a soluabout 80 percent is also preferred when the elastomer is used in a solution. The final film or coating will withstand a 6-foot head of water for one minute but the ammonia or amine vapor or amine transmission rate of the film or coating is sufficient to develop a silver halide emulsion in 1 minute at about 60C.

The fluid activator may be either gaseous or liquid. If gaseous, it is used with a binder for the light-sensitive material or overcoat over the element which it penetrates but does not dissolve or make tacky.

In the same manner, the liquid activator may be used alone or mixed with one or more solvents depending upon the particular binder or overcoat used to obtain a dry processed element. Any convenient ratio of solvents can be used providing sufficient alkaline material penetrates the outermost layers of the exposed element to form an image in the silver halide layer having a density (D,,,,, of at least 0.5 in 5 minutes at 20C.

In the event a fluid activator is used with a binder or overcoat which is hydrophobic but permits penetration of an amine 'or ammonia, gaseous activation can be used. If a liquid activator is desired, a liquid amine can be used or an aqueous solution containing an amine or other alkaline material. In the event an aqueous solution is employed, the preferred weight ratio of amine or alkaline material can be from to 100 percent.

Many different types of amines can be employed in the process of this invention.'Typical examples of these amines are imidazole, alkyl-substituted imidazoles, pyridine, amino-substituted pyridines, guanidines, alkylamines, alkanolamines, alkylenediamines, alkoxyamines, and the like. Particularly preferred for use in the process of this invention because of their freedom from objectionable odors and excellent performance in developing the image are amines of the formula:

- derstanding of the invention:

Example 1 Illustration of a Variety of Effective Activators An element as illustrated in FIG. 1 is prepared. The emulsion layer b contains:

6; Gelatin in water 50.0 ml

3-S-Thiuronium-l-methylpropane sulfonate 2.5 grams Methyl gallate l.0 grams l-Phenyl-3-pyrazolidone 0.1 grams -Continued S-Methylbenzotriazole 0.1 grams Silver chloride gelatin emulsion, v

(6% gelatin) lOO mg Ag/ml 12.0 ml

It is coated on polyester film base (layer a)- at a level of 12 mg of silver per square decimeter. The emulsion is then overcoated (layer 0) with cellulose acetate, 40 percent acetyl content, at a level of about 12 mg per square decimeter.

This element is exposed to light, immersed for 10 seconds in IQ percent aqueous solutions of various amines and alkalies at 60C and withdrawn. The draining pat tern is observed: if the solution drains freely and rapidly leaving a completely dry surface, it is termed Good"; if it drains more slowly, or leaves some pattern, the draining is termed Fair; if it wets the surface and leaves appreciable residue, the draining is termed Poorf Similarly, image development is observeda density of about 1.0 is considered Good, higher densities Very good, densities between 0.1 and 0.5, Low, and densities between 0.5 and 1.0 as Fair.

The results obtained with a variety of amines are listed in Table I.

Although they differed in degree of effectiveness, it will be observed that alkali hydroxides and a variety of amines, diamines and other polyamines, heterocyclic amines, alkanol amines, and alkoxy amines penetrate the barrier layer to cause image development and yet drain well from the layer. Certain amines are insuffciently soluble in water to be tested in this system (e.g., phenylethylamine, pentylamine, triethylamine, aniline, and pyrrole). Very weakly alkaline amines; such as, imidazole developed only weakly, and certain other amines (e.g., diethanolamine) penetrate this barrier layer too slowly to be effective in this test but produce images when processing time is prolonged. A few amines, e.g., pyrrolidine, wet this cellulose acetate barrier layer. The preferred amine or alkali is adapted to the barrier layer.

TABLE I Alkali Development Draining Ammonium hydroxide Good Good Methylamine Very good Good lsopropylamine Very good Good Alkylamine Very good Good n-Butylamine Very good Good t-Butylamine Very good Good Benzylamine Very good Good Ethylene diamine Very good Good l-Aminoethanol Fair Good 2 Aminoethanol Fair Good l-Amino-2-propanol Fair Good 2-Amino2-methyl-l-propanol Fair Good N,N-Diethylamine Good Good N-Methyl-N-butylamine Good Fair N-Bis-hydroxyethyl-N-ethylamine Weak Good N-Hydroxypropyl-N-diethylamine Fair Good Pipcrazine Good Good Z-Methylpiperazine Very good Fair N-Methylimidazole Good Good 2-Ethyl-4-methylimidazole Good Good Z-Aminopyridine Fair Good Hexamethyleneimine Very good Good Propane-1,2-diamine Very good Good Propane-1,3-diamine Very good Good Hexane-l ,6-diamine Very good Good N.N-Diethylethylene diamine Very good Good N,N-Dimethyl-l,3-propane Very good Good diamine N,N-Diethyl-l ,3-propane Very-good Good diamine l,4-Cyclohexanebis(methylamine) Very good Good Diethylene triamine Good Good TABLE I-Continued TABLE 111 Alkali Development Draining Hexarnethylene- 21 vlethyl Max Emulsion Tr et ylene elram ne Fa" Good lmine rmrdazole Density Speed Staln 3,3'-Diaminodipropylamine Very good Good r N,N-Bis( 2-Arninoethyl 1 1 ,3 Good Good :3: ifg;' fgx pmp m 20 20 z lo 0Q to E Very Cyclohexylamine Very good Good g I Z-Methoxyethylamine Very good Fair 3-Methoxypropylamine Very good Good 4-Aminomethylpiperidine Very good Good I Guanidine Fair Good Potassium hydroxide Good Fair IS required to activate the developing agents. It IS ad: Lithium hydroxide Very good Fair vantageous In some applications 0 U58 8 mixture 01 Example 2 Illustration of Concentration Effects The element of Example l is exposed to light behind a step wedge and is then processed by immersion in aqueous solutions of ethanolamine for the times and temperatures indicated in Table II. The higher concentrations of ethanolamine after advantagesin improved density and decreased fog and stain. In each case, ex-

cess solution in squeeged from the surface to produce dry, hard film which can be handled freely or rolled on itself. The images are transparent, stable and unaffected by prolonged exposure to daylight.

Example 3 Non-Aqueous Solvent Example 4 Alternative Barrier Layer The barrier layer of Example 1 is replaced with a layer containing cellulose acetate butyrate, 17 percent butyryl. The layer is also modified by the inclusion of 10 percent triphenyl phosphate as a plasticizer. The coating level is approximately that of Example 1, about 12 mg per square decimeter. The film is exposed to light behind a step wedge and immersed in a 50percent solution of ethanolamine at 60C for 12 seconds. On

withdrawl, the solution drains from the barrier layer to leave a firm surface. The image has high density (2.15) and contrast (y 2.3) and is stable toward further exposure to light.

Example 5 Mixture of Amines The element of Example 1 contains both developing agents and a stabilizer precursor (3-S-thiuronium propane sulfonate). The stabilizer precursor may be freed by nuclear addition of even a weakly alkaline amine (e.g., 2-methylimidazole) whereas a more alkaline amine (e.g., hexamethyleneimine) amines to obtain a desired competitive effect between the developing and fixing reactions. The element of Example l is exposed to light and processed in the mixture of amines, as indicated in Table 111 for 5 seconds at 49C. The results obtained are indicated in Table III. The addition of methyl imidazole causes some loss in emulsion speed but produces higher maximum density and lower stain.

Example 6 Freedom from Tackiness Each strip (35 mm wide) is immersed in a 50-50 by weight water-ethanolamine solution for 15 seconds at 57C, withdrawn through squeegees, and pressed by rollers under 15 lb. pressure into contact with an unprocessed piece of the same film. After contact times of either (a) 20 seconds or (b) 50 minutes, they are stripped apart, using a spring gauge to measure the force needed for stripping. The results are entered in Table IV. The effectiveness of the overcoats in reducing tack is clearly shown.

TABLE IV overcoating Adhesion20 sec. After 50 min.

None H2 02. 1% oz. Cellulose Acetate 0 oz. 0 oz. Copolymer Silicone /a Oz. -Vs oz.

Solution A section of film similar to that used in Example 1,

TABLE II Stain Ethanolumine Time Temp Image Fog (to blue Percent (Sec) (C) Gamma Density (Gross) light) Example 8 An Overcoating Formed From a Terpolymer A terpolymer, 2.5 percent in acetone, is spread at 0.002 inch wet thickness over the hardened coating of Example 7 and dried. The overcoated material is held under a stream of water and removed from the stream.

The water rolls from the surface leaving a dry surface. 'Po|y[methyl methacrylate-co-2-( N,N-dimethylamino)ethyl methacrylate-co-acrylic acid] (wt. ratio 6461304150) The photographic layer is activated with methylamine gas, producing a black image on a clear background. The surface of the coating is tack free. The processed coating is placed under a stream of water and when removed, the water rolls off the surface leaving the surface dry.

Example 9 An Overcoating Formed With a Copolymer A Copolymer, percent in acetone, is used in place of the terpolymer of the preceeding example. The results of the water and photographic tests are similar to those given by the terpolymer. Polylmethyl methacrylate-co-Z-tN,N-dimethylamino) ethyl methyacrylateI (wt. ratio 50:50)

The concentration of the polymer solution can vary over a wide range. The limits are defined by the physical capability of forming a continuous film at the low level and by the amine penetration rate at the high level. Where the polymer has low penetrability to amine, a low level of polymer is indicated.

Example 10 A Polyvinyl Butyral Overcoat The emulsion of Example 8 is overcoated with a solution of 0.9 grams of Butvar (polyvinyl butyral) in 150 ml of isopropyl alcohol, at 0.002 inches wet thickness. After drying the layer is immersed in a 50-50 by weight ethanolamine-water solution for seconds at 59C. A dense image is produced. Using the adhesion test of Example 7, adhesion after seconds Contact time is zero ounces and after 3% hours is one-half ounce.

Photographic silver halide emulsions, preparations, a addenda, processing and systems may be used as disclosed in paragraphs I through XVIII and XXIll in Product Licensing Index, December 1971.

The invention has been described with particular reference to preferred embodiments therein but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. A process for obtaining an image in an exposed radiation-sensitive silver halide element comprising contacting said element with an alkaline fluid activator comprising an amine or ammonia, said element comprising a support substantially impermeable to said fluid, having thereon an exposed radiation-sensitive silver halide emulsion layer, said element containing a developing agent for said silver halide and having an outermost hydrophobic layer, said hydrophobic layer being permeable to an amine or ammonia and being substantially free from tackiness after being removed from contact withv said fluid.

2. A process of claim 1 for obtaining a silver image in a radiation-sensitive silver halide element comprising contacting said element with a solvent containing an alkaline material.

3. A process of claim 2 in which said element also contains a stabilizer precursor capable of activation in an alkaline material.

4. A process of claim 1 comprising contacting said element with an alkaline fluid comprising a liquid containing an alkaline material or an alkaline gas, in which said element comprises a hydrophobic overcoat permeable to said alkaline material or gas.

5. A process of claim 4 in which said element contains a stabilizer precursor capable of activation in an alkaline material under said overcoat.

6. A process of claim 5 in which:

a. said radiation-sensitive silver halide layer is contained in a hydrophilic binder,

b. said developing agent is contained in a hydrophilic binder,

c. maintaining said element in contact with said fluid for a time sufficient to develop a silver image but insufficient to render said element tacky, and

d. removing said developed element from contact with said fluid.

7. A process of claim 6 in which said fluid is an alkaline solution.

8. A process of claim 6 in which said fluid is ammonia or amine vapor.

9. A process of claim 1 in which said element comprises at least one exposed radiation-sensitive silver halide layer, and atleast one layer containing silver halide developing agent, the surface of said uppermost layer in said element being substantially free from tack after contacting with said fluid.

10. A process of claim 9 in which said element also comprises at least one layer containing a stabilizer precursor.

ll. A multilayer radiation-sensitive element comprising a water-impermeable support having thereon a radiation-sensitive silver halide emulsion layer, said element containing a silver halide developing agent and a stabilizer precursor and having an outermost hydrophobic layer said hydrophobic layer being permeable to ammonia or an amine.

12. An element of claim 11 in which said developing agent comprises methyl gallate.

13. An element of claim 11 in which said developing agent comprises 1-phenyl-3-pyrazolidone.

.14. An element of claim 11 in which said developing agent comprises ascorbic acid.

15. An element of claim 11 in which said developing agent comprises a 4,5,6-trihydroxy pyrimidine.

16. An element of claim 11 in which said stabilizer precursor comprises 3-S-thiuronium l-methyl-propane sulfonate.

17. An element of claim 11 in which said stabilizer precursor comprises 3-S-thiuronium propane sulfonate.

18. An element of claim 11 in which said overcoat comprises cellulose ester.

19. An element of claim 11 in which said overcoat comprises cellulose acetate.

20. An element of claim 11 in which said overcoat comprises cellulose acetate butyrate.

21. An element of claim 11 in which said overcoat comprises a cellulose ether.

22. An element of claim 11 in which said overcoat comprises ethyl cellulose.

23. An element of claim 11 in which said overcoat is a mixture of methylmethacrylate-butyl acrylate copolymer and a partial ester of a styrene-maleic acid copolypercursor is contained in the same layer with said silver halide.

Claims (25)

1. 2. A process of claim 1 for obtaining a silver image in a radiation-sensitive silver halide element comprising contacting said element with a solvent containing an alkaline material.
2. 3. A process of claim 2 in which said element also contains a stabilizer precursor capable of activation in an alkaline material.
3. 4. A process of claim 1 comprising contacting said element with an alkaline fluid comprising a liquid containing an alkaline material or an alkaline gas, in which said element comprises a hydrophobic overcoat permeable to said alkaline material or gas.
4. 5. A process of claim 4 in which said element contains a stabilizer precursor capable of activation in an alkaline material under said overcoat.
5. 6. A process of claim 5 in which: a. said radiation-sensitive silver halide layer is contained in a hydrophilic binder, b. said developing agent is contained in a hydrophilic binder, c. maintaining said element in contact with said fluid for a time sufficient to develop a silver image but insufficient to render said element tacky, and d. removing said developed element from contact with said fluid.
6. 7. A process of claim 6 in which said fluid is an alkaline solution.
7. 8. A process of claim 6 in which said fluid is ammonia or amine vapor.
8. 9. A process of claim 1 in which said element comprises at least one exposed radiation-sensitive silver halide layer, and at least one layer containing silver halide developing agent, the surface of said uppermost layer in said element being substantially free from tack after contacting with said fluid.
9. 10. A process of claim 9 in which said element also comprises at least one layer containing a stabilizer precursor.
10. 11. A multilayer radiation-sensitive element comprising a water-impermeable support having thereon a radiation-sensitive silver halide emulsion layer, said element containing a silver halide developing agent and a stabilizer precursor and having an outermost hydrophobic layer said hydrophobic layer being permeable to ammonia or an amine.
11. 12. An element of claim 11 in which said developing agent comprises methyl gallate.
12. 13. An element of claim 11 in which said developing agent comprises 1-phenyl-3-pyrazolidone.
13. 14. An element of claim 11 in which said developing agent comprises ascorbic acid.
14. 15. An element of claim 11 in which said developing agent comprises a 4,5,6-trihydroxy pyrimidine.
15. 16. An element of claim 11 in which said stabilizer precursor comprises 3-S-thiuronium 1-methyl-propane sulfonate.
16. 17. An element of claim 11 in which said stabilizer precursor comprises 3-S-thiuRonium propane sulfonate.
17. 18. An element of claim 11 in which said overcoat comprises cellulose ester.
18. 19. An element of claim 11 in which said overcoat comprises cellulose acetate.
19. 20. An element of claim 11 in which said overcoat comprises cellulose acetate butyrate.
20. 21. An element of claim 11 in which said overcoat comprises a cellulose ether.
21. 22. An element of claim 11 in which said overcoat comprises ethyl cellulose.
22. 23. An element of claim 11 in which said overcoat is a mixture of methylmethacrylate-butyl acrylate copolymer and a partial ester of a styrene-maleic acid copolymer.
23. 24. An element of claim 11 in which said overcoat comprises a polysiloxane.
24. 25. An element of claim 11 in which said developing agent is contained in the same layer with said silver halide.
25. 26. An element of claim 11 in which said stabilizer percursor is contained in the same layer with said silver halide.

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