CA1246923A - Self-fixing imaging film containing reductant precursor - Google Patents

Abstract

ABSTRACT

Improved imaging film-forming compositions and improved organo-tellurium imaging films are provided that require no separate fixing. Normal development of the film by application of heat re-sults in a fixed film.

Description

61~
~Z'~69~23 This application relates to improved imaging films and more particularly to improved imaging films containing reducible organo imaging com-pounds, such as organo-tellurium imaging com-pounds, and reductant precursors which are fixedas a result of development.
Various methods are known for producing im-ages or duplicates of images. The imaging materi-als used are, in certain cases, particular organic compounds. Some of these heretofore known methods employ mixtures of inorganic compounds such as silver halide with one or more particular types of organic compounds as sensitizers.
A new photographic process using telluriu~
compounds to provide the image is disclosed in U.S. Patent ~o. 4,142,896, issued March 6, 1979 to Chang and Ovshinsky. In accordance with U.S.
Patent No. 4,142,896, an emulsion is formed using certain reducible tellurium compounds in combina-tion wi.h a reductant precursor in a binder ormatrix suitable for forming a film-like coating on a substrate. The film prepared therefrom is ex-posed image-wise to activating energy and is thereafter developed as is known in the art here-inafter described. Heat development is preferred.

~6~3 Some tellurium compounds described for use in the photographic process of UOS. Patent No.
4,142,896 may be represented, for example, by the formula Rx-Te-Xy in which R is an organic radical containing at least one carbonyl group, X is halogen, preferably chlorine, and x is l, 2 or 3, and x -~ y = 4. The organic radical R may be either two independent radicals or may be joined together to form a cy-clic compound. Another group of compounds men-tioned in U.S. Patent No. 4,142,896 are organic tellurium compounds which may be considered or characterized as tellurium tetrahalide adducts of ethylenic or acetylenic hydrocarbons. Some of such compounds can be represented by the formulae X
I

X - R - Te - R1 - X

X

and (x-R)n-Te-xn wherein R and R1 are each the residue of an eth-ylenic hydrocarbon and X is a halogen, preferablychlorine.

6~3 Another category of photosensitive tellurium compounds which have been found useful are halo-genated tellurium compounds~ such as compounds of the formula TeClnBrm where n is an integer from 2 to ~, and n + m = 4.
The use of such halogenated tellurium compounds in imaging processes is disclosed in U.S. Patent 4,066,~60 issued January 3, 197~ to Chang et al.
Still another category of useful tellurium compounds are described in U.S. Patent 4,106,939 issued August 15, 197~ to Chang, Ovshinsky and Strand. These compounds are tellurium tetrahalide adducts of aromatic amines in which nitrogen at-tached directly or indirectly to the aromatic ring is substituted by alkyls of 1-4 carbon atoms, the adduct being free of diazo groups.
The tellurium compounds such as the foregoing may be employed in conjunction with a reductant-~recursor which serves as a sensitizer. The re-ductant-precursor i5 a compound which, under the influence of activating energy, will absorb radia-tion energy and abstract labile hydroyen from an appropriate hydrogen donor to become a strong re-ducing agent. The strong reducing agent reduces ~G~3~3 the tellurium compound to a divalent telluriumcompound or to elemental tellurium. In either event, a change in optical density occurs which results in an imaging suitable for recording in-formation. In general terms, the foregoing reac-tion may be represented by the following mechan-ism:

PQ hv1pQ ~ 3PQ

3pQ + 2RH ~ PQ-H2 + R-R

(R1)2~Te X2 -~ 2PQ H2 ~ 2PQ + 2RlH=Te ~ 2HX
wherein PQ is the reductant precursor sensitizing agent; lPQ is the first excited singlet state thereof; 3pQ is the triplet state thereof; RH is the hydrogen donor; PQ-:~2 is the reductant pre-cursor in its reduced state; and (R1)2 Te X2 is the reducible tellurium image-forming compound.
In this connection, it should be noted that the hydrogen donor need not be specifically pro-vided, although a variety of alcohols can be usediL desired. In the absence of a specially-provid-ed hydrogen donor, the labile hydrogen can some-times be abstracted from the organic resins used as binders. In other cases, the sensitizer can be its own hydrogen donor~ and this is known to be ::~Z'~6~3 ~, the case with at least one sensitizer~ namely, isoproxynaphthoquinone.
Desirable materials for the binder or matrix include, for example, polymers such as poly(vinyl alcohol),poly(acrylonitrile), poly(butadiene), poly(ethylene), poly(ethyleneglycol), polymers marketed by the ~onsanto Co. under the trade mark "FORMVAR" and polymers marketed by the Eastman Kodak Company under the trade mar.l; "CAB", especially "CAB-500-5".
A modification of the tellurium photographic process is described in Belgian Patent No.
854,193, wherein certain diols of the formula R10-cHOH--z-cHoH-R1 1 may be employed as the hydrogen donor for use in conjunction with the photosensitizer described above. In the foregoing formula, R10 and R11 rep-resent hydrogen and various organic substituents.
Z may be a direct carbon-carbon linkage between the two hydroxy substituted carbon atoms, or may be any of various linking groups. Reference is made to Belgian Patent No. 854,193 for a fuller description of the diols referred to. In the Belgian patent, these diols are said to serve as hydrogen donors. Subsequent research has sug-.~:
, -~

~Z46~3 gested that this is not completely accurate. In fact, a major portion of the diol appears to form a complex with the tellurium compound.
This finding has led to the discovery of diols of the general formula R-O-CH2CHOH-CH20~
which have improved characteristics when used in tellurium-based photographic films.
The radical R may be a simple aliphatic ~roup (for example, alkyl or alkenyl). Alternatively, the radical R may contain a carbonyl group (for example, an acyl radical). Preferably, however, the radical R is aromatic. Best results are ob-tained where the aromatic ring is separated from ~he ether oxygen by one methylene grouping. A
more complete description of these diols is con-tained in United States Patent No. 4,281,058, is-sued July 28, 1981 to Ovshinsky et al. and refer-ence is made thereto for additional descriptions thereof.
Still another modification in the use of tel-lurium compounds as photosensitive agents involves what is known as a "masked reducing agent". A
number of compounds are known, such as phenidone, which will reduce organo-tellurium compounds. The 6~3 reducing capacity of such compounds may be "masked" - i.e., inhibited - by appropriate sub-stitution. In such cases, if the substituent is one which can be cleaved by the reaction products liberated upon the photoreduction of the tellurium compound, the masked reducing agent can be used to amplify the photoresponse through the mechanism Light + Sensitizer ~ Photoactive Reducing Agent Photoactive Reducing Agent + Tellurium Compound Tellurium By-Products By-Products + Masked Reducing Agent -Demasked Reducing Agent Demasked Reducing Agent + Tellurium Compound ~
Tellurium By-Products Since the organo-tellurium compounds commonly used release hydrogen halides (particularly hydro-gen chlorides) as by-products of the red~ction re-action, and the reducing agents, such as pheni-done, are amino compounds, the masking agents most effectively employed are compounds which will con-vert the amino nitrogen into an amide. A typical masked reducing agent thus is the compound 1-phenyl-2-benzoylamido-3-pyrazolidinone:

~6~23 N~ O O
~ - C - NHC ~

A more complete description of masked reducing agents may be found in Belgian Patent 863,052 of July 19, 1978, and reference thereto is made for additional descriptions thereof.
As an alternative to the masked reducing agents described in Belgian Patent 863,052, a new class of masked reducing agents may be substitut-ed, represented by the general formulae Rl-~Y-NY2;

R2 ~o R3 _ ~ `N-'' \ ; or R4 y ~0 N

~4~3 wherein Y is hydrogen or CNHR5, said compound con-l taining at least one C-N~I-R5 group. In the fore-going formulae, R1 may be alkyl, alkanoyl, alkoxy-carbonyl, phenyl, ~enzyl, benzoyl, nitrophenyl, benzylcarbonyl, phenylmethyl, phenylethyl or phenylpropylcarbonyl, or aminocarbonyl. ~2~ R3 and R4 each, and independently, may be hydrogen, alkyl or phenyl and amino. R~ may be phenyl, ni-trophenyl, halophenyl, alkyl, mono-, di- or tri haloalkyl, benzoyl, alkylphenyl, or alkylcyano-phenyl. The masking group may be substituted at either one or both of the amino hydrogen sites of the reducing agent. The alkyl groups referred to above may contain up to seven carbon atoms. Such compounds are conveniently accessible through re-action of the parent hydrazine or pyrazoline with an isocyanate of the Eormula R5-N=C=o In practice, the foregoing ingredients, i.e., a tellurium derivative, a reductant precursor sensitizer, and additional ingredients such as the glycol and masked reducing agent, are combined in a suitable matrix to form an emulsion which may be spread into a film on àn appropriate carrier or ~2~69~3 substrate. A latent image in the film is formed by exposure to imaging energy, for example, a light irnage.
After formation of the latent image, a visi-ble image is developed, such as by heating the ex-posed film as described in Unlted States Patent ~o. 4,1~2,896. After development of the visible image, the film is desirably fixed to avoid dark-ening or other undesirable modification of the film resulting Erom exposure to light or the pas-sage of time. United ~tates Patent No. 4,1~2,896 also describes a method of fixing the tellurium imaging film by removing the sensitizer and inact-ivating unreacted imaging organo-tellurium materi-al. In accordance with the teaching of that pa-tent the film is fixed by contacting the film with a chloroform/toluene (20:80 by volume) solution saturated with ammonia or with organic amines.
However, this fixing is relatively slow, generally taking about thirty rninutes. Further, that fixing method requires the use of relatively toxic and hazardous compounds. The use of chloroform/
toluene is unsuitable for several types of desir-able matrix polymers, such as the CAB type, be-cause the chloroform/toluene mixture dissolves such polymers. Another type of fixing method ispossible in which the film is fixed by contacting the film with an alcohol, such as isopropanol, for example. A small amount of ketone such as ace-tone, for example, may also be included with thealcohol. Especially useful is a solution of 50 parts isopropanol/1 part acetone (by volume).
Thus, it would be desirable to provide an imaging film of the foregoing type which does not require separate fixing.
We have found that the above discussed disad-vantages in the use of imaging films have been overcome by the creation of self-fixing, dry pro-cess imaging films that are made by controlling the amount of reductant precursor present in the filmO The reductant precursor must be limited to an amount such that essentially all of the reduc-tant precusor is removed from the film as a result of heat development. Varying the amount of reduc-tant precursor for a particular composition willalso provide the desired film speed and optical density.
In accordance with the present invention, methods and dry process imaging films which uti-lize a reductant precursor and a reducible imaging ~2~69~3 compound are provided which are self-fixing. A
separate fixing step or fixing chemicals are not required and a fixed film is provided as a result of normal developing conditions, such as heating at from about 150-155C for about 30-90 seconds, for example. Thus, the above described imaging system containing a reducible imaging compound and a reductant precursor is improved.
More specifically, I have discovered that self-fixing dry process imaging films can be made by controlling the amount of reductant precursor present in the film. The amount of reductant pre-cursor present in the film is present in a limited amount such that under normal developing condi-tions, essentially all of the reductant precursoris extracted by heat development of the film. As used herein, the time of normal development is about five minutes or less. Preferably, the film is such that substantially all of the reductant precursor is removed from the film after less than about two minutes of development at about 150C.
It is the unreacted reductant precursor (i.e. that which is not changed to a reducing agent as a re-sult of exposure to imaging energy~ that must be removed. The type of reductant precursor utilized 6~ ~ 3 should be heat-extractable when combined with the other film components in a matrix. The actual physical phenomenon that takes place, which could be, for example, evaporation, sublimation or some other phenomenon, is not important to practicing the present invention. It is only necessary that essentially all of the reductant precursor be re-moved from the film as a result of heat develop-ment. Thus, in formulating imaging films in ac-cordance with the invention, the film-forming com-position, comprising an image-forming compound and a reductant precursor, contains a proper amount of reductant precursor so that when film made from the film-forming composition is developed by heat, essentially all of the reductant precursor is re-moved. As used herein, "essentially all of the reductant precursor" means that a sufficient amount such that the amount remaining does not cause the film to be significantly altered by the passage of time or exposure to light. The film-forming compositions may contain other components, as discussed.
The amount of reductant precursor present in the film-forming compositions is variable. Gener-ally, sufficient reductant precursor is present ~2~L~9~3 such that film made from the composition produces the desired change in optical density to allow formation of an image. The specific amount of re-ductant precursor will be dependent upon the type of reductant precursor and the other components present in the film-forming composition. However, the amount of reductant precursor should not be so great as to be present in the film after normal development in amounts which cause the film to darken significantly or produce significant unde-sirable modification of the film as a result of exposure to light or the passage of time. Other than this limitation, the amount of reductant pre-cursor can be as desired, and preferably is that amount for a particular composition which provides the desired film speed and optical density. The optimum amount of a particular reductant precursor for a particular formulation can easily be deter-mined simply by formulating film-forming composi-tions containing various amounts of reductant pre-cursor and testing the performance of the films made therefrom.
An emulsion formulated in accordance with the present invention contains a tellurium compound, a reductant precursor and an appropriate matrix.

12~

Optionally, other components may also be included in the emulsion. A diol may be included, prefer-ably a glyceryl compound of U.S. Patent No.
4,281,058. A masked reducing agent or water may be included in the emulsion. A base may also be included, preEerably when a masked reducing agent is included. Finally, an alcohol may also be in-cluded, preferably when a glyceryl compound of ~.S. Patent No. 4,281,058 is included.
It is anticipated that reducible organo-me-tallic imaging compounds and other reducible metal compounds, other than tellurium compounds, may be utilized in accordance with the invention. For example, other metals which can form organo-metal-lic imaging compounds, include copper, silver, nickel, mercury and cobalt. For example, cobalt imaging compounds are disclosed in U.S. Patent No. 4~201,588 to Adin et al. Specific organo-metallic compounds which may be used include, for example, copper-2,4-pentanedionate, nickel-2,4-pentanedionate, mercury acetate and silver behenate.
The image-forming tellurium: A number of image-forming tellurium compounds are described in the prior art and such compounds are generally ~Z~ 3 useful in the ~resent invention. rn general, the present invention contemplates using these and other tellurium compounds which undergo analogous reduction reactions in the presence of a reductant precursor as hereinafter described. Preferably, the image-forming tellurium compound is of the type that requires the presence of a reducing agent, such as a reducing agent formed from a re-ductant precursor upon exposure to imaging energy, to form a significant image. Thus, without the presence of a reducing agent, exposure oE the film to light does not result in the formation of a significant increase of optical density.
It has been found that many tellurium com-pounds possess certain properties which adapt them especially for use in imaging processes. In gen-eral, these are compounds from which, as a result of the imaging and developing steps generally re-ferred to above, elemental tellurium is deposited from the tellurium compounds. Tellurium is chain-forming in character, and it is generally deposited from the tellurium compounds useful Eor photographic purposes (preferably including thin needles), the compounds being capable of rapid nucleation and growth as crystallites, which ~2~

crystallites grow as chains and largely or mainly as needles. Such chains or needles are opaque and are characterized by excellent light scattering properties to produce good optical density ob-served after thermal or other development.
Effects which may involve oxide formation are substantially restricted to surface effects as distinguished from effects which cause degradation through the bodies of the needles or chains.
Preferably, the tellurium imaging compound is an organo-tellurium compound such as disclosed in U.S. Patent No. 4,142,89~ of Chang et al. These compounds are organic tellurium compounds which inherently possess sensitizer properties (and/or may be mixed with a separate sensitizer) in which the tellurium is linked directly to at least one carbon atom or the organic radical of the organo-tellurium material, the organic tellurium compound being of one structure and having a detectable characteristic which is capable of undergoing a change in response to the application of imaging energy in the form of particle or wave radiation to produce a material of different structure hav ing another detectable characteristic. The mate-rial having a different structure and different detectable characteristics resulting from the imaging step is sometimes referred to as the "image~forming compound".
The tellurium imaging compound may be an organo-metallic compound such as disclosed in U.S. Patent No. 4,062,6~5.
A particularly advantageous subgroup of the imaging organo-tellurium compounds utilized in the practice of the present invention comprises organ-ic compounds which contain an organo radical andhalogen attached directly to the tellurium atom, there being at least one carbonyl group in the or-gano radical. Certain of them are adducts of tel-lurium halides, notably tellurium tetrachloride, with organic compounds, notably ketones or similar chromophores, containing at least one carbonyl group in the organic compound. They may, thus, be considered or characterized as organo-tellurium compounds or adducts containing halogen, namely, chlorine, bromine, iodine, and fluorine, attached directly to the tellurium atom. ~ost of this par-ticular class or group of said imaging ~ompounds have two carbonyl-containing organo radicals.
Those which are especially useful in the practice of the ~resent invention have chlorine as the ~Z~6~3 , g halogen but, in certain cases, although generally less satisfactory, other halogens can be present.
The imaging compounds should be selected to be soluble or homogeneously dispersible in any par-ticular matrix material which may be utilized, asis described hereafter. Many of this group of im-aging organo-tellurium compounds may be represent-ed by the formula Rx~Te -lialy where R is an organo radical containing at least one carbonyl group, Hal is halogen, especially chlorine, x is 1, 2 or 3, and x ~ y = 4, subject to the proviso that Te is linked directly to car-bon in an organo radical. Preferably, x is 2 or 3.
Others can be represented by the formula R2-Te-Hal4 where R is a carbonyl-containing organic radical, and Hal is halogen.
The R radical can be aliphatic, cycloali-phatic or aromatic (mononuclear or dinuclear) or a combination thereof and may contain one or more hetero atoms in the chain or rings. It may be un-substituted or substituted by various organic or inorganic radicals~ which may assist in or at ~2~

least do not lnterfere with the desired imaging effect, illustrative of such radicals being C1-C6 alkyl, corresponding oxyalkyl radicalsr acetyl, nitro, C--N, Cl, sr, F, etc. Generally speaking, the aforesaid organo-tellurium imaging compounds which contain a trihalide group as, for instance, acetophenone tellurium trichloride, tend to have relatively low melting points (about 70-80C), and are more hygroscopic and less stable than those 1~ generally similar compounds containing two halogen atoms and, therefore, such trihalides are less desirable for use in the practice of the present invention.
~ more limited class of this particular sub-group oE imaging organo-tellurium compounds may be represented by the formula (Ar-CO-CH2) 2Te-Hal2 where Ar is an aromatic hydrocarbon radical, which may be substituted or unsubstituted, as indicated above, and Hal is halogen, especially chlorine.
This subgroup of compounds, particularly where Hal is chlorine, represents especially advantageous embodiments of the invention, with respect to the imaging organo-tellurium compounds which are used in the practice of the present invention.

~692~

Another subgroup of imaging organo-tellurium compounds, useful in the practice of and contem-~lated by the present inventionl which do not con-tain a carbonyl group in an organo radical but in wnich tellurium is linked directly to carbon are compounds which may be considered or characterized as tellurium tetrahalide adducts of ethylenic or of acetylenic hydrocarbons. These compounds are generally conveniently produced by reacting 1 to 2 moles, particularly 2 moles, of t'ne ethylenic or acetylenic hydrocarbon with 1 mole of tellurium tetrahalide, especially preferred for such use being TeC14. Certain of such compounds can be represented by the formulae:
Hal I

Hal - -- R7 Te - R6 Hal ; and I

Hal (Hal R7)x _ Te - Haly where R6 and R7 are each the residue of an ethyl-enic hydrocarbon, for instance, an alkene or a cycloalkene, Hal is chlorine, bromine or iodine, especially chlorine, x is 1 to 3, and x ~ y = 4.

~l2~323 ~22-Illustrative of the ethylenic and acetylenic hydrocarbons which can be adducted with tellurium tetrahalides to produce such imaging organo-tellu-rium compounds are propylene; butene-1; isobutyl-ene; butene-2; 2,3-dimethyl-2-butene; 3,3-di-methyl-1-butene; 2,4-dimethyl-1-pentene; 4,4-di-methyl-1-pentene; 2,5-dimethyl-3-hexene; dipent-ene; 1,1-diphenylethylene; 1-heptene; 1-hexene;

2-methyl-1-hexene; 3-methyl-1-hexene; 4-methyl-1-hexene; 2-ethyl-1-hexene; 2-isopropyl-1-hexene;
2-methyl-1-pentene; 2-methyl-2-pentene; 2-ethyl-2-pentene; 3-methyl-1-pentene; piperylene; vinyl-cyclohexene; vinylcyclopentene; 2-vinylnaphthal-ene; 1,2,4-trivinylcyclohexene; 4-methyl-1-cyclo-hexene; 3-methyl-1-cyclohexene; 1-methyl-1-cyclo-hexene; 1-methyl-1-cyclopentene; cycloheptene;
cyclopentene; cyclohexene; 4,4 dimethyl-1-cyclo-hexene; 2-methylbutene-1; 3-methylbutene-1; and 1-octene; lower alkyl and lower alkoxy derivatives of various of the alkenes such as cyclohexene; 1-pentyne; 2-pentyne; 1-hexyne; and 3-methyl-1-butyne.
rrhe preparation of the aforementioned organic tellurium compounds as well as many examples thereof are more fully set forth in U.S. ~atent ~,142,896.

As indicated above, tetrahalides of tellurium in which the halide is at least one member select-ed from the group consisting of chlorine and bro-mine are also useful as the image-forming material in the present invention. Such tellurium halides are fully described in U.S. Patent No. 4,066r460.
Certain of these imaging materials can be represented by the formula TeClnBrm where n is an integer from 1 to 4 and m + n - 4.
Typical tellurium tetrahalides which may be used are Tecl4; Tecl2Br2; and TeClBr3. TeCl4 is espe-cially useful. Reference is made to U.S. Patent 4,066,460 for a fuller description of these tellu-rium tetrahalides and their use as image-forming compounds.
Still another group of image-forming com-pounds are certain compounds derived from telluri-um tetrahalides which are described in U.S. Patent ~0 4,106,939 to Chang et al. These involved com-pounds are adducts of tellurium tetrahalide with aromatic amines exemplified by the tellurium tetrachloride adduct of dimethylaniline, which ad-duct is free of diazo groups. More specifically, these tellurium tetrahalide adducts are Eormed by ~6~3 combining a tellurium tetrahalide with an aromatic amine in which nitrogen attached directly or indi-rectly to the aromatic radical is substituted by alkyls containing from 1 to 4 carbon atoms, the imaging organo-tellurium material being free from diazo groups.
These aromatic amine adducts of the tellurium tetrahalides are fully described in U.S. Patent 4,106,93~ to Chang et al.
The active tellurium compounds may, if de-sired, be formed in situ, for example, by using bis(acetophenone) tellurium dichloride or a tellu-rium oxide or a tellurium salt in combination with a suitable organic compound. Sometimes the in situ formation is promoted by the presence of an acid. For example, tellurium oxide or alkali metal tellurates may be combined with one of the glycols described below to form a tellurium-organ ic compound complex which is active. It is be-lieved that the reaction is analogous to the reac-tion between organic tellurium compounds such as described above and a diol. Preliminary informa-tion suggests that the reaction is favored by an acidic medium. Small amounts of an acid such as anhydrous hydrogen chloride may be added. Alter-124~;9~

natively, halogen-containing tellurium compounds will provide the requisite acidity.
The reductant precursor: In addition to the tellurium image-forming compound, the imaging systems of the present invention include a reduc-tant precursor, or sensitizer, which, as described above, is a compound that, under the influence of activating energy, has the property of extracting labile hydrogen from a hydrogen donor to become a reducing agent with respect to the image-forming tellurium compound. The activated reducing agent then reduces the tellurium compound to produce the desired image. The hydrogen donor may be an ex-ternal source of hydrogen such as an alcohol spe-cifically provided for the purpose. However, thehydrogen donor may equally well be an appropriate group which is a part of the molecular structure of the reductant precursor.
Preferred reductant precursors useful in the present invention are quinones, particularly 2-isopropox~napthoquinone; 9,10-phenanthenequinone;
and 2-t-butylanthraquinone. Other specific reduc-tant precursors include: 3-chloro-2-isopropoxy-1, 4-naphthoquinone; 3-chloro-2-isopropoxy-1,~-anthraquinone; 3-chloro-2-isopropoxy-~,7-diphenyl-1,4-naphthoquinone; 3-chloro-2-(3'-Pentoxy)-1,4-naphthoquinone; 3-chloro-2-(2'-butoxy)-1,4-naphthoquinone; 3-chloro-2-(3',3'-di-methyl-2'-butoxy)-1,4-naphthoquinone; 2,3-diiso-propoxy-1,4-naphthoquinone; 3-chloro-2-methoxy-1, 4-naphthoquinone; 2,3-dimethoxy-1,4-naphthoqui-none; 3-chloro-2-(t-butoxy)-1,4-naphthoquinone;

3-chloro-2-ethoxy-1,4-naphthoquinone; 3-chloro-2-(n-butoxy)1,4-naphthoquinone; 3-chloro-2-(2'-methylpropoxy)-1,4-naphthoquinone; and 2-isopro-poxy-1~4-anthraquinone. Especially useful reduc-tant precursors from the aforementioned group in-clude 3-chloro-2-isopropoxy-1,4-naphthoquinone, 3-chloro-2-isopropoxy-1,4-anthraquinone and 2,3-diisopropoxy-1,4-naphthoquinone. These reductant precursors exhibit good sensitivity to electromag-netic radiation in the visible range, while allow-ing the ~ilm to have good speed.
Benzophenone/ although not a quinone, is also useful as a reductant precursor, as are a number of the simpler ketones.
A factor of importance in the selection of reductant precursors is the spectral range to 3: ~3 which the reductant precursors respond. For that reason, the simple ketones are not generally use-ful for recording visible light since their spec-tral sensitivity is in the far ultraviolet region.
The following are illustrative reductant pre-cursors which are sensitive in the range of up to about 400 nm and, therefore, are useful only in the ultraviolet range: Benzophenone; acetophe-none; 1,5-diphenyl-1,3,5-pentanetrione; ninhydrin;

4,4'-dibromobenzophenone; and 1,8-dichloroanthra-quinone.
Various other reductant precursors can be utilized, particularly those of the type of sub-stituted or unsubstituted polynuclear quinones, of which class some have been mentioned above, and others of which are 1,2-benzanthraquinone; 2-methylanthraquinone; 1-chloroanthraquinone;
7,8,9,10-tetrahydronaphthacenequinone; 9,10-anthraquinone; and 1,4-dimethylanthraquinone. rt will be understood that not all reductant precur-sors will be effective or equally effective, with each given imaging material, even taking into ac-count the utilization of imaging energy in the sensitlvity range of the reductant precursor em-ployed and that suitable selections of combina-3~

tions of particular imaging materials and partic-ular reductant precursors will be required to be ~-nade for achieving desirable or optimum results.
Further, various reductant precursors will require different amounts of heating during development in order to remove substantially all of the reductant precursor from the film. Such selections, how~
ever, can be made relatively readily.
In general, in connection with the foregoing matters, it may be noted that reductant precursors have n ~* states, both singlet and triplet, of lower energies than ~, ~* states and, at least in most cases, compounds which have their ~, ~*
states of lowest energy will not be photosensi-tively effective, although, in certain limitedcases, compounds which fulfill the test of having lower energy n ~ ~ * than ~ ~ ~ * transitions do not function as reductant precursors. However, the above consideration is, in the main, an eE-fective one for determining in advance whether agiven compound will function as a reductant pre-cursor for use in the practice of the present in-vention. In any event, a simple preliminary em-pirical test in any given instance can readily be carried out if necessary by preparing a test emul-~lZ~23 sion using the desired imaging compound and reduc-tant precursor.
Preparation of certain preferred reductant precursors in accordance with the invention is now described. Generally, to form the naphthoquinones or anthraquinones in accordance with the inven-tion, a suitable starting material is reacted with a suitable alkoxide to form the desired reductant precursor.
When it is desired to form a reductant pre-cursor of the general formula `Y, O
wherein Y1 is alkoxy and Y2 is alkoxy or chloro, 2,3-dichloro-1,4-naphthoquinone is reacted with a metal alkoxide, such as a sodium alkox.ide, the alkoxide corresponding with the desired alkoxy group. The metal alkoxide can be formed by react-ing an alcohol with an active metal, such as sodi-um. For example, the reaction of sodium with iso-propanol yields sodium isopropoxide. Irhus, tc prepare 2,3-diisopropoxy-1,4-naphthoquinone, sodi-um isopropoxide is reacted with 2,3-dichloro-1,4-naphthoquinone, preferably at room temperature, ;9~3 forming 2,3-diisopropoxy-1,4-naphthoquinone. 2-chloro-3-isopropoxy-1,4-naphthoquinone is prepared in a similar manner, except that the alkoxide is added slowly to a cooled (preferably 0-5C or about ice bath temperature) suspension o~ 2,3-di-chloro-1,4-naphthoquinone. In this manner, only one of the chloro groups is replaced by an isopro-poxy group. Other reductant precursors in accord-ance with the invention having one alkoxy group and one chloro group, such as 3-chloro-2-(2'-butoxy)-1,4-naphthoquinone, 2~chloro-3-isopro-poxy-1,4-anthraquinone and 2-chloro-3-isopropoxy-6,7-diphenyl-1,4-naphthoquinone, can be prepared in a similar manner. The latter two compounds would be prepared from 2,3-dichloro-1,4-naphtho-quinone and 2,3-dichloro-6,7-diphenyl~1,4-naphtho-quinone, respectively.
If Y1 and Y2 are different alkoxy, one alkox-ide is added slowly to replace one chloro and the product recovered and then the product is reacted in a similar manner with the other alkoxide.
Reductant precursors of the general ~ormula ~ ~ Y3 where Y1 is alkoxy and Y3 is hydrogen, chloro or alkoxy can be prepared by reacting 2-chloro-1,4-anthraquinone (if Y3 is to be hydrogen) or 2,3-di-chloro-1,4-anthraquinone (if Y3 is to be chloro or alkoxy) with a suitable metal alkoxide as previ-ously described with respect to the naphthoqui-nones.
Reductant precursors of the general formula ~ Y~

r~ ~ ~ Y4 where Y1 is alkoxy and Y4 is hydro~en, chloro or alkoxy can be prepared by reacting 2,3-diphenyl-butadiene with 2,3-dichlorobenzoquinone in acetic acid to give 2,3-dichloro-6,7-diphenyl-1,4-naph-thoquinone, which is then reacted with a metal alkoxide as previously described with respect to 2,3-dichloro-1,4-naphthoquinone. Alternatively, where ~4 is hydrogen, 2-chlorobenzoquinone is uti-lized in place of 2,3-dichlorobenzoquinone.
The Masked Xeducing Agent: In accordance with the invention, a masked reducing agent may be in-cluded. A typical masked reducing agent thus is the compound 1-phenyl-2 benzoylamido-3-pyrazolidi-none:

3~2~

[~
N O O
/ \ 11 11 Nl - C - NHC
- \\o A more complete description of masked reducing agents may be found in Belgian Patent 863,052 of July 19, 1978, and reference thereto is made for additional descriptions thereof.
As an alternative to the masked reducing agents described in Belgian Patent 863,052, a new class of masked reducing agents may be substitut-ed, represented by the general formulae R1-NY-NY2;

R2 o ~ 4 R3 ~ ~ ~ ; or 20~ /NY
o T

wherein Y is hydrogen or CNHR5, said compound con-O
taining at least one C-NH-R5 group. In the fore-~lZ~6~3 going formulae, R1 may be alkyl, alkanoyl, alkoxy-carbonyl, phenyl, benzyl, benzoyl, nitrophenyl, benzylcarbonyl, phenylmethyl, phenylethyl or phenylpropylcarbonyl, or aminocarbonyl. R2, R3 and R4 each, and independently, may be hydrogen, alkyl or phenyl and amino. R4 may be phenyll ni-trophenyl, halophenyl, alkyl, mono-, di- or tri-haloalkyl, benzoyl, alkylphenyl, or alkylcyano-phenyl. The masking group may be substituted at either one or both of the amino hydrogen sites of the reducing agent. The alkyl groups referred to above may contain up to seven carbon atoms. Such compounds are conveniently accessible through re-action of the parent hydrazine or pyrazoline with an isocyanate of the formula R5-N=C=o The Base: When a masked reducing agent is utilized, a base can be included. The inclusion of a base provides the unexpected result of im-proving the speed (light sensitivity) and/or im-proving the optical density of the exposed por-tions after development of imaging film made with such compositions. The inclusion of a base may also reduce the background fog or optical density of unexposed portions of the film. The composi-tions may contain other components, as discussed.

;23 The base may be organic or inorganic and should be sufficiently alkaline to ionize the masked reducing agent. In general, any base which improves the performance of the film, such as, for example, increased speed, increased optical densi-ty of exposed portions or decreased fog of unex-posed portions, can be utilized. Preferably, bases which produce unwanted deleterious effects will be avoided. Suitable inorganic bases in-clude, for example, metal hydroxides and ammoniumhydroxide. More specifically, alkali metal hy-droxides and alkaline earth metal hydroxides can be utilized. Useful alkali metal hydroxides in-clude those of lithium, sodium, potassium, rubidi-um and cesium. Lithium hydroxide is the preferredalkali metal hydroxide. Useful alkaline earth metal hydroxides include those of magnesium, cal-cium and barium. The hydrated form of the metal hydroxide can be used. It is anticipated that more than one base can be included in the imaging film composition.
Alternatively, the organic base may be an aliphatic amine compound or a nitrogen atom con-taining heterocyclic compound.

Suitable amines for use in accordance with the invention include primary, secondary and ter-tiary amines which may be aliphatic or aromatic.
i~ore particularly, suitable amines are those such as, for example, methylamine, di-methylamine, tri-methylamine, ethylamine, diethylamine, triethyl-amine, n-, di-n- and tri-n- propylamine, isopro-pylamine, n-butylamine, isobutylamine, sec-butyl-amine, tertbutylamine~ and n-tetradecylamine. In general, those amines o~ the following formula may be suitable:
R - N~2 where R is aliphatic (for example CH3, C2H5~ C3H7, etc.).
The R radical may be unsubstituted or substi-tuted by various organic or inorganic radicals, which do not interfere with the desired imaging effect~
Cyclic compounds, such as pyridine and piper-idine, are also suitable, and may be unsubstitutedor substituted by various organic or inorganic radicals, which do not interfere with the desired imaging effect.
While not wishing to be bound by theory, it is believed that the base ionizes the masked re-lZ~6~3 ducing agent facilitating the formation of a com-plex between the ionized masked reducing agent, positive tellurium ions and the latent image formed by the reductant precursor after exposure of the film to imaging energy. The complex is be-lieved to be very susceptible to electron trans-fer, facilitating formation of a visible image.
In general, alkaline earth or alkali metal hydroxides are preferred over organic bases. The metal ions from the base may form a beneficial complex with the reductant precursor which makes the reductant precursor more active.
The amount of base present in the film-form-ing composition is variable. Generally, there is no minimum amount of base required to provide an improved film~ However, the degree of improvement is related to the amount of base present, up to a certain amount, for each particuar film formula-tion and base. Beyond that amount, generally the photoresponse of the film diminishes. The optimum amount of a particular base for a particular for-mulation can easily be determined simply by formu-lating film-forming compositions containing vari-ous amounts of a particular base and testing the performance of the films made there~rom.

~24~3 The Diol: In accordance with the present in-vention, there may also be included a diol which reacts with the tellurium compound to form an ac-tive intermediate complex. While the chemistry of the complex is not well understood, we believe that, in general/ the complex requires approxi-mately 2 moles of diol for each mole of telluri-um. Preferably, the diol, when present, is used in excess of the minimum amount to form a complex since the diol will also function as a source of labile hydrogen to provide the source of hydrogen required in the reaction of the reductant precur-sor.
While the present invention can be practiced without the inclusion of a diol, the presence of a diol is preferred especially when a masked reduc-ing agent is present. The presence of a diol serves to marXedly reduce the optical density of unexposed areas (i.e., thus increasing the con-trast between the exposed and unexposed areas).Thus, while masked reducing agents can be used in the absence of a diol, tellurium film compositions containing masked reducing agents tend to have a relatively high optical density in the unexposed areas because the reducing capacity of the masked 6~

-3~-reducing agent is not fully inhibited by the mask-ing group.
One group of diols which may be used in for-mulating imaging compositions are diols of the formula H H

OH OH
wherein each of R8 and R9 independently represents hydrogen, a hydrocarbon group, including straight chain, branched chain and cyclic hydrocarbon groups~ hydroxyalkyl groups, alkoxycarbonyl groups, cycloalkyl groups or aryl groups; and 2 represents an arylene group (for example, phenylene), the group (-C_C-), the group (-CR10=CRll)n~ wherein n represents a whole num-ber, for example, 1 or 2, and each of R10 and R
represents hydrogen or an alkyl group or taken from part of a carbocyclic or heterocyclic ring.
Z also may be omitted - that is, the two hydroxy-substituted carbons are joined directly to each other. The following table illustrates a number of diols which may be used:

Boiling Point (BP) No. of the C or Melting Compound R8 z R9 Point (MP) C

2 ~3 H MP 67 4 ~3C- ~ -CH3 BP 183 6 H ~/ ~ H MP 112 7 HO(CH2)4 ~ H BP 178/5 mm Hg 8 C2E15fi- - C2H5O-CI- BP 280 O O
A fuller description of the foregoing diols may be found in the disclosure of Belgian Patent 854,193.
Preferably, however, the diol is of a more complex type than disclosed in the above-mentiond Belgian patent application. These more complex diols are the subject matter of U.S. Patent No.
4,281,058.
The preferred diols, as described in U.S.
Patent No. 4,281,058, are compounds of the formula In the foregoing compound, R12 may be alkyl, acyl, thiazolinyl, alkenyl, phenyl, alkylphenyl, alkenylphenyl, hydroxyalkylphenyl, benzyl, alkyl-benzyl, alkoxybenzyl, hydroxyalkylbenzyl, or halo-benzyl and similar radicals.
The "thio" analogs of the foregoing compounds can be used (i.e., compounds in which the radical 212 is joined to the glycerol residue by a thio linkage in place of the oxy linkage).
Preferred compounds of the Eoregoing struc-ture are those in which the radical R12 is benzyl or a substituted benzyl. The use of the diols of the foregoing structure has been found to be pre-ferred since they are more effective in reducing the optical density of the unexposed areas than are the diols described in Belgian Patent 854,193.
Ancillary Ingredient_: In addition to the foregoing principal ingredients of the present formulation, ancillary ingredients may be included for various purposes. Thus, for example, it has been found that certain materials enhance the shelf life o~ unexposed virgin dry film composi-tions of the present invention, and in certain in-stances, they also enhance the sensitivity of said film compositions. Illustrative embodiments of such additional or supplemental materials, which contain ether or polyether linkages in the mole-~24~;~3~2~

cules thereof, are such materials or polymers as polyethylene-20 sorbitan monolaurate, polyethyl-ene-20 sorbitan monooleate; Polyox-10; Polyox-80;
Polyox-750; polyethylene glycol-~00 distearate;
s polyethylene glycol-600 distearate; poly (1,3-di-oxolane); poly (tetrahydrofuran); poly (1,3-dioxe-pane); poly (1,3-dioxane); polyacetaldehydes;
polyoxymethylenes; fatty acid esters of polyoxy-methylenes; poly (cyclohexane methylene oxide);
poly (4-methyl-1,3-dioxane); polyoxetanes; poly-phenylene oxides; poly [3,3-bis (halomethyl) oxo-cyclobutane]; poly (oxypropylene) glycol epoxy resins; and copolymers of propylene oxides and styrene oxides. Such materials can be incorporat-ed in the imaging film compositions in varyingamounts, generally from 5 to 20% by weight of the solid imaging film compositions. In certain cases they enhance or prolong the shelf life or storage life, under given storage conditions, as much as 50~ or even very substantially more timewise, and, as indicated, they also, in various cases, effec-tively increase film sensitivity.
Again, the inclusion in the imaging films of reducing sugars has been found~ generally speak-ing, to bring about an enhancement in density of :~2~6~3 the image area (O.D. image - O.D. background), when the film is imaged as disclosed above and then developed, for instance, at about 120-150C
and for the order of about 15 seconds, especially where the imaging film is freshly prepared or not older than about a day after initial preparation.
Such films, when exposed to imaging energy and then developed resulted in the yroduction of a positive image (iOe., the optical density is greater in the nonexposed areas than in the ex-posed areas) in contrast to the negative working system which exists in the usual practice of the present invention. The inclusion of reducin~
sugars in the imaging compositions also enables development oE the image, after exposure to imag-ing energy, to take place at lower temperatures, even at room temperatures, in a period of several hours, for instance, commonly in 10, 12 or 15 hours. The reducing sugars which can be employed are many, illustrative of which are dextrose, glu-cose, arabinose, erythrose, fructose, galactose, fucose, mannose and ribose. Especially effective are dextrose, arabinose, galactose, fucose and ribose. The reducing sugars can be used in vari-able amounts, but generally in equivalent amounts, or somewhat smaller or greater, in relation to the amount of imaging organo-tellurium materials in the imaging compositions.
It may be desirable in many cases to include a small amount of silicone oil or similar material as is well known to aid in coating of smooth con-tinuous films.
Several other ancillary ingredients may be utili~ed, which can have the effect of increasing the sensitivity of the film and/or optical density after exposure. These ancillary ingredients in-clude: indoaniline dyes of the general formula 0~N~N\ R3 R4--~> R 1 where R1 _ R4 r may be, each and independent-ly by hydrogen or alkyl (N,N-(p-dimethylamino-phenyl)~1,4-naphthoquinone(indophenol blue) for example); indane-1,3-dione derivatives such as 2-phenylindane-1,3-dione; and cyanine dyes of the general formula ~ N' ~ CH (CH = CH~

where n=1, 2 or 3 and x is chloro or iodo (1,1'-diethyl-2,2'-carbocyamine chloride (pinacyanol chloride) for example).
The matrix material: A film composition in accordance with the present invention is completed by dissolving the ingredients and optional ingre-dients described above in a suitable matrix. The matrix should be as concentrated as is practicable in the active ingredients, i.e., the least amount of matrix is preferably used. The amount of ma-trix should be sufficient as to just retain the various active ingredients in a solid solution.
An additional quantity of matrix may be used, how-ever, that obviously tends to dilute the concen-tration of active ingredients, thereby slowingdown the photo-response of the film composition.
The selection of matrix materials, of course, must be related to the active ingredients used so as to provide the maximurn solubility for any particular composition.
The matrix materials, into which the imaging organo-tellurium materials, and the separate sen-sitizers when employed, are incorporated to pro-duce the imaging film or coating, are solids at room temperature, and they can be selected from a ~2~Z3 relatively large number of materials. Care should be taken to insure that the matrix mate~ial does not absorb undesired com~onents, such as excess water from the atmosphere. They should desirably be at least in part of amorphous character and it is especially desirable that they be glassy, polar amorphous materials naving a glass transition tem-perature, which desirably should not exceed about 200C and may be as low as about 50C, and, better still, should be within the ran~e of about 80-120 C. They are generally polymeric materi-als. Illustrative thereof are cyanoethylated starches, celluloses and amyloses having a degree of substitution of cyanoethylation of > 2; poly-vinylbenzophenone; polyvinylidene chloride; poly-ethylene terephthalate ( MYLAR*); cellulose esters and ethers such as cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, acetyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, poly-vinylcarbazole; polyvinyl chloride; polyvinyl methyl ketone; polyvinyl alcohol; polyvinylpyr-rolidone; polyvinyl methyl ether; copolymers of vinylidene chloride and acrylonitrile; polyvinyl acetate, polyvinyl butylral; polystyrene; poly-*trade mark , z~

methyl methacrylate; polyvinyl pyrrolidone; sty-renebutadiene copolymers; polyamides; polyacrylic and polymethacrylic alkyl esters such as poly-methyl methacrylate and polyethyl methacrylate;
copolymer of polyvinyl methyl ether and maleic an-hydride; various grades of polyvinyl formal resins such as so-called 12/85, 6/95E, 15/95S, 15/95E, B-79, B-98, and the like, sold under the trademark "FO~MVAR" - (Monsanto Company). Of special utili-ty is polyvinyl ~ormal 15/95~ which is a white,free flowing powder having a molecular weight in the range of 24,000-40,000 and a formal content expressed as percent polyvinyl formal of approxi mately 82%, possessing high thermal stability, ex-cellent mechanical durability, and resistance tosuch materials as aliphatic hydrocarbons, and min-eral, animal and vegetable oils. These polymeric materials or resins and their preparation are well known to the art. Also of special utility are various grades of cellulose acetate butyrate poly-mers sold by the Eastman Kodak Company under the trade designation "CAB", particularly "CA8 500-5".
In addition to their functioning as carriers for and holding together in a unitary composition the imaging organo-tellurium materials, sensitiz-~47-ers and any other ingredients which may be incor-porated into the imaging film or coating or layer and their functioning as dry or essentially dry film-forming materials to provide thin films and providing mechanical durability in the finished imaged film, at least many of them appear also to play a chemical or physical role in the imaging process by providing, importantly, a source of readily easily abstractable hydroyen and, thus, appear to play a significant role in the latent image formation mechanism, as discussed here-after. In certain instances, it may be desirable to decrease the viscosity of the matrix, which can be done, by way of illustration, by the addition of certain plasticizers, for instance, dibutylph-thalate or diphenylphthalate, wh.ich additions tend to result in the production of images desirably of higher optical densities but which, however, also tend to have the disadvantage of increasing back-ground fogging.
It rnay be noted that matrix materials of thetype which contain basic groups may complex with the imaging organo-tellurium materials and, there-fore, to the extent that such complexing may oc-cur, the use of such matrix materials should beavoided.

~2~9~

-~8-Alcohol: The compositions of the invention may include an alcohol. Preferably, the alcohol will be utilized when a diol as previously de-scribed is present in the composition. The alco-hol and diol may form a complex with the telluriumcompound, providing a film having enhanced speed and/or improved background fog. The alcohol may be primary, secondary Gr tertiary. Primary mono-hydric alcohols are preferred, such as n-butanol and n-propanol, for example.
Water: The composition may also include water. A small quantity of water, generally added to the matrix material, prior to combination with the other film-forming components, serves to im-prove the speed of the film. However, too muchwater may cause a tellurium oxide to be precipi-tated when the components of the film-forming com~
position are combined, and this should be avoided.
Formulation of Film Compositions: In the production of the films or thin layers of the im-aging material compositions, which are generally prepared in the form of solutions or homogeneous dispersions and coated or laid down on a sub-strate, it is especially desirable to dissolve or homogeneously disperse the ingredients in an or-~:Z4~2~

ganic solvent. Illustrative of suitable solvents are methyl ethyl ketone (MEK), dimethylformamide (DMF), chloroform, tetrahydrofuran (THF), di-methylacetamide (DMA), dioxane, dichloromethane and ethylene dichloride, or compatible mixtures of such organic solvents or with other organic sol-vents. A particularly useful solvent is a 50:50 mixture of dichloromethane and methyl ethyl ke-tone. After the solution or homogeneous disper-sion is formed on a substrate in any suitable man-ner, the major proportions of such organic solvent or solvents are evaporated off, preferably at a relatively low temperature and, sometimes desirab-ly, under subatmospheric pressures or in vacuo, until the film or coating is substantially dry to the touch, such dry-to-the-touch coating being es-pecially desirable for handling and processing purposes. Although such films or coatinqs rnay be, generally speaking, dry to the touch, it should be understood that this does not mean that the film is free from organic solvent. Indeed, it has been found that it is frequently very desirable that the finished films or coatings, prior to exposure to imaging energy, contain a small percentage, commonly of the general order of about 2 to 3~, by 6~23 weight of the film or coating, or organic solvent, for instance, dimethylformamide (DMF) since its presence appears to play a favorable role in the sensitivity of the system in relation to the latent image formation and/or ultimate image ob-tained after the development step. The elimina-tion of all or essentially all of the DMF, or other organic solvent or solvents, from the virgin film prior to the imaging and development fre-quently leads to a decrease in sensitivity. Inany event, in any given instance where drying of the virgin imaging film has been carried out to a point where essentially no organic solvent is present, and whereby sensitivity is unduly re-duced, sensitivity can be increased or restored by adding a small amount of organic solvent to the film prior to exposing it to imaging energy.
The imaging film or coating thickness are variable but will usually fall within the range of 20 about 1 to about 35 ~m with about 5 to 15 ~m gen-erally being a good average. Preferably, the thickness of the coating is about 20 ~m. General-ly, increases in the coating thickness make remov-al of the reductant precursor as a result of heat development more difficult.

The production of the imaging organo-telluri-um materials~ and the coating, handling and pro-cessing operations, to ti1e extent which may be re-quired, are carried out under appropriate light conditions, as those skilled in the art will read-ily understand. For instance, the formulation of the coating compositions and the coating and dry-ing operations are conveniently carried out under amberlite filtered light (weak transmission at 550 nm). The dry film prior to imaging, is desirably stored in the dark. In certain cases, avoidance oE contact of certain of the ingredients with cer-tain metals may be in order where undesired reac-tions, such as reductions, may occur. In general, the vessels or containers~ stirrers, etc., uti-lized should be made of glass or other vitreous materials or other materials inert to the coating ingredients to insure against contamination or possible undesired reactions. It is advantageous, in general, to prepare the imaging compositions shortly prior to coating them on the selected sub-strate. Under suitable storage conditions, which generally are conditions of darkness and reason-able avoidance of air or oxidizing atmospheres and humidity conditions, the stability of the imaging compositions is good.

~Z~ 3 In the imaging compositions, the proportions of the matrix, the imaging organo-tellurium mate-rial and the reductant precursor are variable. In any event, generally speaking, excluding the or-ganic solvent or solvents, where employed asdescribed below, at least in most cases the matrix ~aterial, which is a normally solid material, that is, solid at room temperature, will be employed in amounts in excess of any one of the other materi-als and will also usually be present in majoramount, that is more than 50% and broadly in the range up to 90~ by weight, of the total materials present in the imaging composition. The imaging organo-tellurium material, generally also a nor-mally solid material, will ordinarily constitutefrom about I to above 20 parts per 100 parts of matrix, usually about 5-1n parts per 100 parts of matrix. The reductant precursor, where it is a separate ingredient, which is usually a solid, will usually be employed in lesser proportions, commonly of the order of about 0.5 to 3%, usually about o.a to 2.0%, by weight, of the imaging com-position. With further regard to the proportions of the aforesaid ingredients, it may be stated that the area density of the reductant precursor is desirably selected so that up to about 7~-95%
of the photons falling on the film in the region of the absorption bands of the reductant precursor are absorbed. Considerably higher concentrations of reductant precursor would leave the dark side of the film unexposed and no advantage would thus be served. In general, for optimal results in many cases, the mole concentration of the imaging organo-tellurium material to that of the reductant precursor should be about 5:2. The concentration of the polymer matrix material should be suffici-ent to produce an essentially amorphous film with-out bringing about precipitation of the imaging organo-tellurium material, the sensitizer and other supplemental ingredients when utilized.
E~cess polymer matrix material also tends to de-crease the sensitivity of the film.
The amount of diol should be present in a concentration sufficient to provide at least 2 moles of diol for each mole of tellurium compound, and preferably to provide up to a ratio of 6:1 moles. As indicated above, our work has suggested that a complex is formed between the diol and the tellurium compound in a molar ratio of 2:1, and that excess diol above that is useful to provide a 1~6~3Z3 source of labile hydrogen for reaction with the reductant precursor. Larger amounts of the diol may be used if desired. To some extent, improved results are obtained when these larger amounts of

5 diol are used; however, there is a point of dimin-ishing returns above which increasing the amount of diol will not provide commensurate improvement in photoresponse of the finished film.
The masked reducing agent may be present in amounts of 1% up to 200~ by weight of the telluri-um compounds. Measurably improved sensitivity can be found in accordance with the present invention with even very small amounts of mas~ed reducing agent and within limitations the degree of im-provement is in proportion to the amount of maskedreducing agent which is incorporated in the film.
Again, howevex, a law of diminishing returns is observed, and while large amounts of the masked reducing agent will be incorporated, on the order of 2 to 4 times the amount of tellurium compound, beyond these large amounts the increase in photo-response obtained is not commensurate with the in-creased amount of masked reducing agent incorpo-rated.

~Z4~;~3;~

The film-forming compositions as described above will be applied to any suitable substrate.
Glass, porcelain, paper and various plastic sub-strates have been found suitable. For the pur-poses of forming film-like materials, transparency is obviously desirable. For this purpose, film of polyethylene terephthalate have been found par-ticularly suitable. Other substrates include, for example, polyimides, nylon and triacetyl cellu-lose.
Additional considerations which those skilledin the art in formulating and using tellurium-based film compositions may utilize are apparent from U.S. Patent No. 4,142,896.
This invention is further illustrated by the following examples:
Example 1 A tellurium imaging film in accordance with the invention was made and tested. 0.625 grams of bis(acetophenone) tellurium dichloride, 0.15 grams of isopropoxy-1,4-naphthoquinone (IPNQ), 0.625 grams of masked 1-phenyl-3-pyrazolidone of the formula:

3~

~ -56-,N\ O O
~ N ~ C -- NHC ~
-~0 2.4 grams of ortho-methoxy benzyl glyceryl ether, 10.42 grams of CAB-500-5, 3.0 milliliters of n-butanol and 160 milliliters of a 50:50 mixture (by volume) of methylene dichloride and methyl ethyl ketone were stirred together in complete darkness at room temperature until a homogeneous viscous solution was obtained. The solution was then coated on a polyester substrate at a thick-ness of 20~ and the resulting film heated in an oven at 50C for three hours.
The film was tested by exposing the film to imaging energy through a photographic step tablet having eleven steps and an optical density range of approximately 0.3 to 3.05. The step tablet was in contact with the film during exposure. A
Honeywell Strobonar Model No. 710 Xenon flash tube was utilized to provide irnaging energy, spaced ap-proximately nine inches from the film. After ex-posure, the film was developed by heating the film at a temperature of 150C for either 45 or 90 seconds. The developed film was tested to deter-mine how well the film was fixed by placing a frame of the film in a Bell & Howell Model SR-VIII
microfilm reader for one or more hours in the viewing position. The minimum and maximum optical density (OD) of the film was thereafter measured 5 with a MacBeth Model T-P 504 Densitometer using a red filter. The following results were obtained:
Time In Microfilm Reader Development 0 1 2 4 8 20 Time Hour _ourHoursHours HoursHours 1045 seconds OD Min 0.23 0.280.31 0.36 0.42 OD Max 1.79 1.781.78 1.77 1.78 g0 seconds OD Min 0.29 0.290.29 0.30 0.30 0c30 OD Max1.8810881.87 1.86 l.86 1.84 ~2~ 23 Example 2 The same procedure set Eorth in Example 1 was utilized to make and test film made as in Example 1 except that 0.190 grams of 3-chloro-1-isopro-poxy-1,4-naphthoquinone (CIPN~3 was utilized in place of IPNQ. The following results were ob-tained:
Time in Microfilm Reader __ _ Development 0 4 20 10Time Hour Hours Hours .
45 seconds OD Min 0.23 0.35 0.35 OD Max 1.94 1.95 1.91 90 seconds OD Min 0.35 0O31 0.26 OD Max 2.12 2.01 1.97 Example 3 The same procedure set forth in Example 1 was utilized to make and test film made as in Example 1 except that in place of IPNQ, 0.315 grams of 2,3-diisopropoxy-1,~-naphthoquinone was utilized.

The following results were obtained:

Time In Microfilm Reader Development 0 20 25Time H _ Hours 90 secondsOD Min 0.36 0.28 OD Max 1.65 1.65 Example 4 The same procedure set forth in Example 1 was utilized to test film made as in example 1, from the following composition: 0.625 grams of bis(acetophenone) tellurium dichloride, 0.15 grams of isopropoxy-1,4-naphthoquinone (IPNQ), 0.625 grams of masked 1-phenyl-3-pyrazolidone of the formula: ~

N O O
~ - C - NHC ~

2.4 grams of ortho-methoxy benzyl glyceryl ether, 10.42 grams of CAB-500-5, 3.0 milliliters of n-butanol, 0.3 grams of 2-phenylidone-1,3-dione (PID), 4 milligrams of pinacyanol chloride (QB), 3 milligrams of lithium hydroxide (LiOH-H2O), 3 milligrams of indophenol blue (IPB) and 1~0 milliliters of a 50:50 mixture (by volume) of methylene dichloride and methyl ethyl ketone. The following results were obtained:

~65~3 __ Time in Microfilm Reader Development 0 1 2 4 8 20 48 Time Hour Hour Hours Hours Hours Hours Hours 45 seconds 5OD Min 0.24 0.31 0.33 0.40 - - -OD Max 2.07 2.07 2.11 2.11 90 seconds OD Min 0.28 0.29 0.30 0.30 0.27 0.24 0.24 OD Max 1.95 1.95 1.95 1.94 1.95 1.93 1.91 Example 5 The same procedure set forth in Example 1 was utilized to make and test the film of Example 4 except that in place of IPNQ, 0.190 grams of CIPNQ
was utilized. The following results were ob-15 tained:
T_e In Microfilm Reader Development 0 20 Time H_ Hours 90 seconds OD Min 0.23 0.21 20 OD ilax 2.11 2.04 :~4~3~3 Example 6 The same procedure set Eorth in Example 1 was utilized to make and test the film of Example 4 except that in place oE IPNQ, 0.315 grams of DIPNQ
were utilized. The Eollowing results were ob-tained:
Time in MicroEilm Reader Develop- 0 1 2 4 8 20 48 ment Time Hour Bour Hours Hours Hours Hours Hours 90 seconds OD Min 0.27 0.27 0.27 0.27 0.27 0.24 0.24 OD Max 1.75 1.75 1.75 1.75 1.75 1.75 1.71 While the invention has been described with respect to specific embodiments, it is to be un-derstood that various changes and modificationswill be suggested to one skilled in the art, and it is intended to encompass such changes as fall within the scope of the appended claims.

Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for recording electromagnetic radi-ation in which a fixed image is provided wherein said method comprises imagewise impinging said radiation upon a photo-sensitive film to produce a change in at least one property thereof, said film being made from a film-forming com-position, which composition comprises:
(a) a reducible image forming compound;
(b) a reductant precursor which will abstract labile hydrogen from a labile hydrogen source under the in-fluence of imaging energy to become a reducing agent with respect to the image forming compound, said reductant pre-cursor present in an amount such that when the film is developed normally by heating, essentially all of the re-ductant precursor is removed from the film and the film is thereby fixed, said amount of reductant precursor being in the range of from about 0.5% to about 3.0% by weight of the total film-forming composition;
(c) a source of labile hydrogen for reaction with said reductant precursor; and (d) a matrix in which said reducible image form-ing compound, reductant precursor and source of labile hydro-gen are combined in amounts effective to form a composition which may be applied to a substrate;
said method further comprising subjecting the film after said impinging to normal development by heating for a period of time sufficient to develop and fix the film by removing essentially all of the reductant precursor.

2. The film as recited in claim 1, wherein said image forming compound is selected from the group consist-ing of ; and in the foregoing formulae, R being an organic radical con-taining at least 1 carbonyl group, R2 being the residue of an ethylenic hydrocarbon, Hal being halogen, x being 1, 2 or 3; and x + y = 4; n being an integer from 1 to 4 and m + n = 4.

3. The method as recited in claim 1 wherein the thickness of the film-forming composition is between about 1 and 35 micrometers.

4. The method as recited in claim 1 wherein the thickness of the film-forming composition is about 20 micrometers.

5. The method as recited in claim 1 wherein development at about 150°C for about two minutes or less causes substantially all of said reductant precursor to be removed from the film.

6. The method as recited in claim 1 wherein said image forming compound is an organo imaging compound selected from the group consisting of organo compounds of copper, silver, nickel, mercury, cobalt and tellurium.

7. A method for recording electromagnetic radia-tion in which a fixed image is provided wherein said method comprises imagewise impinging said radiation upon a photo-sensitive film to produce a change in at least one property thereof, said film being made from a film-forming com-position, which composition comprises:
(a) an image forming tellurium compound;
(b) a reductant precursor which will abstract labile hydrogen from a labile hydrogen source under the influence of imaging energy to become a reducing agent with respect to the image forming tellurium compound, said reduc-tant precursor present in an amount such that when the film is developed normally by heating, essentially all of the reductant precursor is removed from the film and the film is thereby fixed, said amount of reductant precursor being in the range of from about 0.5% to about 3.0% by weight of the total film-forming composition;
(c) a source of labile hydrogen for reaction with said reductant precursor; and (d) a matrix in which said tellurium compound, said reductant precursor and source of labile hydrogen are combined in amounts effective to form a composition which may be applied to a substrate;
the method further comprising subjecting the film after said impinging to normal development by heating for a period of time sufficient to develop and fix the film by removing essentially all of the reductant precursor.

8. The method as recited in claim 7 wherein there is additionally provided a diol of the formula wherein each of R4 and R5 independently represents hydro-gen, a hydrocarbon group, including straight chain, branched chain and cyclic hydrocarbon groups, hydroxyalkyl groups, alkoxycarbonyl groups, cycloalkyl groups or aryl groups;
and Z represents a direct C-C bond between the carbon atoms on either side of it, or an arylene group, the group (-C?C), the group (-CR6=CR7)n, wherein n represents 1 or 2, and each of R6 and R7 represents hydrogen or an alkyl group or taken from part of a carbocyelic or heterocyelic ring, said diol being provided in an amount equivalent to at least 2 moles thereof per 1 mole of said tellurium forming compound.

9. The method as recited in claim 7 wherein there is provided a diol of the formula wherein R7 is alkyl, alkanoyl, thiazolinyl, alkenyl, benzyl, alkylbenzyl, alkoxybenzyl, hydroxyalkyl-benzyl, and halobenzyl; the alkyl radical having from 1 to 7 carbon atoms; and X is oxygen or sulphur.

10. The method as recited in claim 7, wherein said tellurium compound is selected from the group consist-ing of Rx-Te Haly;
(Hal- R2)x - Te - Haly; and TeClnBrm in the foregoing formulae, R2 being an organic radical containing at least 1 carbonyl group, R2 being the residue of an ethylenic hydrocarbon, Hal being halogen, x being 1, 2 or 3; and x + y = 4; n being an integer from 1 to 4 and m + n = 4.

11. The method as recited in claim 9, said com-position further comprising a masked reducing agent.

12. The method as recited in claim 9 wherein said composition further comprises an alcohol.

13. The method as recited in claim 7 wherein the thickness of the film-forming composition is between about 1 and 35 micrometers.

14. The method as recited in claim 7 wherein he thickness of the film-forming composition is about 20 micrometers.

15. The method as recited in claim 7 wherein develop-ment at about 150°C for about two minutes or less causes substantially all of said reductant precursor to be removed from the film.

16. The method as recited in claim 7 wherein said composition further comprises water.