US3565628A - Dye sensitized light sensitive systems incorporating an iodide - Google Patents

Abstract

A DYE SENSITIZED ORGANIC PHOTOSENSITIVE COMPOSITION WITH ITS SENSITIVITY EXTENDED BY THE INCORPORATION OF AN IODIDE.

Description

3,565,628 DYE SENSITIZED LIGHT SENSITIVE SYSTEMS INCORPORATING AN IODIDE Thomas Howard Garland, El Monte, and Yoshikazu Yamada, Sierra Madre, Califl, assignors to Bell & Howell Company, Chicago, 11]., a corporation of Illinois No Drawing. Filed July 11, 1967, Ser. No. 652,430

Int. Cl. G03c 1/72 US. C]. 96-90 23 Claims ABSTRACT OF THE DISCLOSURE A dye sensitized organic photosensitive composition with its sensitivity extended by the incorporation of an iodide.

CROSS-REFERENCE TO RELATED APPLICATIONS BACKGROUND OF THE INVENTION (1) Field of the invention The field of art to which the invention pertains includes the field of photographic chemistry, particularly light-sensitive compositions including those involving light-sensitive dyes.

(2) Description of the prior art A variety of organic photosensitive systems are known in the art. Generally they involve two or more organic materials which react under the influence of actinic light to produce a color. As early as 1921, Murray C. Beebe and his coworkers described numerous organic photographic systems (e.g., U.S. Pats. Nos. 1,574,357; 1,574,358;

1,574,359; 1,575,143; 1,583,519; 1,587,269; 1,587,270; 1,587,271; 1,587,272; 1,587,273; 1,587,274; 1,604,674; 1,618,505; 1,655,127; 1,658,510; and 1,820,593). Generally, these systems relate to the use of various halogen compounds (e.g., iodoform and others) in combination with a second ingredient, in which Beebe and subsequent workers have theorized that light effects the release of a radical from the halogen compound which carries out a color-forming reaction with the second compound. Subsequent workers such as Eugene Wainer (e.g., U.S. Pats. Nos, 3,042,515; 3,042,516; 3,042,517; 3,042,518; 3,042,519; 3,046,125; and 3,056,673) and Robert Sprague (U.S. Pat. No. 3,082,086), as well as a number of other workers since the time of Beebe, have continued the development of various photographic systems involving a photo-energized reaction of a combination of a halogen-containing compound and one or more other compounds. Other recent disclosures include British Pat. No. 917,919 and Belgian Pat. No. 596,094.

Wainer has suggested (U.S. Pat. No. 3,042,518) the addition of an inorganic iodine compound, such as inorganic iodide, iodate or periodate, as a method of increasing the photographic speed of some of the foregoing formulations. More recently, it has been discovered that incorporation of certain organic photochemical combinations as dispersions in a continuous phase in which the combinations are substantially insoluble, results in compositions of superior speed. This discovery is described United States Patent O Patented Feb. 23, 1971 in our noted copending application Ser. No. 481,759. The dispersion of the photochemical materials in the nonsolubilizing continuous phase provides in and of itself a marked increase in photographic speed and the addition of iodide, per se, has no significant effect on the speed of the photosensitive materials in such context.

Generally, the latter, non-solubilized, dispersions are sensitive to only a portion of the visible spectrum. Meth ods for extending the sensitivity are described in our copending application Ser. No. 523,705, and involve the addition of a dye (or dye base) sensitizer which, by intimate association with the dispersed chemicals, effectively extends the optical sensitivity of the system. Even here, however, it may be desired to obtain a wavelength response longer than that provided by a particular sensitizer. The only recourse has been to seek a substitute which sensitizes in the longer wavelength regions; but the change to another sensitizer may require sacrificing efficiency and desirable characteristics or properties peculiar to the sensitizer originally employed and with which the system as a whole has been optimized. For example, with our dispersed formulations, certain sensitizers favor a positive-mode reaction, while others favor a negativemode reaction. It is, therefore, advantageous to be able to extend the normal spectral response range obtained with a particular sensitizer by an additive that does not deleteriously affect other aspects of the photochemical composition.

SUMMARY OF THE INVENTION It has now been found that sensitized photosystems as just described can have their sensitivity extended even further by the incorporation of an iodide. Thus our invention contemplates a photosensitive composition comprising a dispersion of organic photochemical material in a continuous phase in which substantial amounts of such material are insoluble, a sensitizer for the material and an iodide.

Incorporation of an iodide extends the sensitivity of the composition and generally improves the overall performance of the sensitizer. In contrast to prior systems, the iodide has no significant effect upon the speed of the unsensitized composition. Wainer discloses (Pat. No. 3,042,518) that a sensitizer may optionally be present with his iodine additive. In contrast, iodide has no signifi cant effect on our dispersions in the absence of a sensitizer. Wainer also teaches the equivalency of iodates to iodides in increasing the speed of his emulsions. Again in contrast, we have found iodates are not operative with our dispersions.

In a preferred embodiment of our invention, the dispersion of photochemical material is capable of yielding color and non-color areas in response, respectively, to high and low levels of exposure. An initial low level exposure deactivates the exposed areas against subsequent color formation; a positive-mode process is therefore obtainable. Incorporating an iodide, as per our invention, is particularly effective in allowing the occurrence of the non-color reaction with extending portions of the spectrum. Accordingly, a process is provided which comprises: providing a sensitized dispersion of image-yielding material in a continuous phase in which substantial amounts of such material are insoluble, the dispersion being capable of yielding color and non-color areas in response, respectively, to high and low levels of exposure; incorporating an iodide; imagewise exposing the dispersion to the low level of exposure to deactivate the imagewise exposed areas against color formation; and then blanket exposing the composition to radiation at the high level of exposure to yield color in areas exclusive of the image-Wise exposed areas.

3 DESCRIPTION OF THE PREFERRED EMBODIMENTS The sensitized combinations that are improved by our invention are dispersed in the form of discrete globules in a continuous phase in which the combination is substantially insoluble. Such dispersions are discussed in detail in our above-noted application Ser. No. 481,759. Generally, the solid-film-forming component used to achieve a continuous phase may be any of a number of generally photographically inert materials, which are, in most cases, soluble in water or so finely dispersible therein in the concentrations of use that for practical purposes there is no distinction betvveen solution and dispersion for these materials in the continuous phase. Such materials include the starch and starch derivatives, proteins (i.e., casein, zein, gelatin, thiolated gelatin, etc.), alginates, gums, and the like materials which are generally considered to be natural derivatives of natural film-forming materials, any one of which in its conventional water-soluble form is used in the practice of the instant invention. In addition, synthetic water-soluble film-formers may also be used to particular advantage in the practice of the invention and such materials include polyvinyl alcohol, commercially available Water-soluble polyacrylics or acrylates (i.e., water-soluble polyacrylic acid salts having substantially the molecular weight and water compatibility of the polyvinyl alcohol), various commercially available amine or aminealdehyde resins, etc. Also, a number of cellulose derivative film-formers may be used, and these include the various water-soluble cellulose ethers, carboxymethylcellulose, hydroxypropylmethylcellulose, etc. Essentially these materials are photo-insensitive and their principal function is that of forming the desired film which will retain the dispersed phase in discrete particle form. Of the above materials, gelatin, casein, polyvinyl alcohol, gum arabic, starch, alkali metal carboxymethylcellulose (e.g., sodium carboxymethylcellulose) and hydroxyethylcellulose are particularly useful in this invention.

The iodide may be incorporated in the formulation during preparation thereof or may be added later by washing a coating of the formulation with a solution of 1od1de. When incorporated during preparation of the coating, 1t may be added to both the binder and photosens tive organic phase, or to the binder only, or to the organic phase only. The term iodide is meant to include both 1norganic and organic compounds yielding the monovalent 1 ion. The availability of the I ion is the lmportant aspect of the additive rather than the particular metal or organic group carrying the iodide. Binary inorganic compounds of iodine of the type MI, particularly Where M is an alkali metal or ammonium ion, are included, such as sodium iodide, potassium iodide and ammonium iodide. Tetrapropylammonium iodide is an example of a suitable organic iodide.

In general, any amount of iodide will improve sensitlzation; a practical upper limit is about three weight percent of the formulation and generally about 0.005 Weight percent wvill noticeably extend the spectral response of the formulation. A preferred range is from about 0.1 to about one Weight percent.

As noted, a sensitizer for the photosensitive material must be present; indeed, iodide has no appreciable effect on our formulation in the absence of a sensitizer. As a sensitizer, one can use any material that sensitizes the composition to which it is added to radiation in a region of the spectrum to Which the composition has otherwise low sensitivity. Generally, it is preferred that such materials have the optical properties of, or be, optical sensitizing dyes or dye bases. Reference can be made to our earlier application Ser. No. 523,705 and to a 1957 publication of Brooker and Vittum entitled A Century of Progress in the Synthesis of Dyes for Photography in The Journal of Photographic Science, vol. 5, 1957, pp. 71-88, the disclosure of such publication being incorporated herein by reference. All of these dyes tend to absorb actinic energy and all have exhibited their ability to transmit the absorbed energy by a physical molecular contact or by engagement to other molecules receptive of actinic energy for purposes of photo-response. Illustrative materials are: compounds having a characteristic rhodamine ring structure and nominal substitution at an amino group, such as the rhodamines (i.e., aminophthaleins); materials having simple (unsubstituted) carbon chains interconnecting fused heterocyclic and benzenoid ring structures, such as pinacyanole and related canbocy-anine, cyanine or isocyanine type dyes or dye bases, such as Ethyl Red; light absorbers containing heterocyclic rings fused with benzeuoid rings, such as eosin dyes; and light absorbers having a triphenylmethane structure such as Crystal Violet, Victoria Blue and Malachite Green, including leuco forms thereof and compounds having thiazine, alizarine, acridine and anthraquinonoid groups or structures, such as Methylene Blue and thionin. In general, light absorbers having a styryl substituent, such as the styryl and azastyryl dyes and dye basis, are particularly useful in our invention, comprising a preferred group of sensitizers. In general, it is preferred to use an optical dye or dye base. It is particularly preferred to use a dye base, such as the styryl dye bases and vinyl homologs thereof. Particularly effective dyes include:

2-( 2-aza-p-dimethylaminostyryl) -benzothiazole,

2- (p-dimethylaminostyryl) -3 ,3 -dimethylindole,

2- (p-dimethylaminostyryl) benzothiazole,

2- p-dimethylaminostyryl -quinoline,

2- (2-aza-p-dimethylaminostyryl)-benzimidazole,

2- (Z-aZa-p-dimethylaminostyryl -thiazole,

4- p-dimethylaminostyryl) uinoline,

2- (p-dimethylaminostyryl) -benzimidazole,

2-3 (3 -ethyl-2 3 -benzothiazolylidene) -propenylquinoline and 2- (p-dimethylaminostyryl) -pyridine,

and the dye bases of each of the above. Each of the above dyes and dye types can be used in their dye form or in their dye base form and reference to a dye is meant to include dye bases as well.

Although various dyes have been described as sensitizers for our invention, the ability of such dyes to form a color is not important to the invention except insofar as related to an ability to selectively absorb and/ or transfer electromagnetic radiation. Thus, a sensitizing amount of the sensitizer is used rather than a color-forming amount, which amounts may be different. In general, about 0.01 to about mg. of sensitizer per gram of image-yielding material is satisfactory.

In a preferred embodiment of the invention, the photosensitive combination comprises at least two starting agents, a color-yielding agent and a photoinitiator. Suitable photoinitiators include compounds which produce free radicals or ions upon exposure to light of a suitable wavelength, such as the haloalkanes, halomethylnaphthalenes, a-haloketones, halogenated acids, sulfonyl chlorides and aroyl peroxides. Such of these materials as are discussed by McCloskey and Bond in Industrial Engineering Chemistry, vol. 47, p. 2125 et seq. (1955) are of interest here, and such disclosure is incorporated herein by reference. Other materials include aromatic hydrocarbon photoinitiators such as found in US. 2,902,421, substituted benzoins described in US. 2,722,512, metal mercaptides as described in US. 2,738,319, benzene thiols as described in US. 2,861,934, ethylenic compounds as described in US. 2,716,633 and thiuram monosulfides as described in US. 2,861,933, the disclosures of the above patents being incorporated herein by reference.

In general, it is preferred that the photo-initiator be an organic halogen compound as these have been found to be the most effective. Such compounds are described in detail in our earlier filed application Ser. No. 481,759. In general, organic halogen compounds are preferred in which there is present at least one active halogen selected from the group consisting of chlorine, bromine and iodine, attached to a carbon atom having not more than one hydrogen atom attached thereto. Examples of such compounds include carbon tetrabromide, tribromochloromethane, dibromodichloromethane, pentabromoethane, hexachloroethane, hexabromoethane, bromotrichloromethane, bromoform, iodoform, l,2,3,4-tetrabromobutane, tribromoacetic acid, 2,2,2-tribromoethanol, tetrachlorotetrahydronaphthalene, 1,1,1 tribromo-2-methyl-2- propanol, carbon tetrachloride, p-dichlorobenzene, 4- bromobiphenyl, 1 chloro-4-nitrobenzene, p-bromoacetanilide, 2,4 dichlorophenol, 1,2,3,4 tetrachlorobenzene, 1,2,3,5 tetrachlorobenzene, brominated polystyrene, nchlorosuccinimide, n-bromosuccinimide, 2 chloroanthraquinone, tetrabromophenolphthalein, tetrabromoo-cresol, and the like. Other examples can be found in our noted earlier application and also in certain patents issued to Eugene Wainer and Robert Sprague such as US. Pats. Nos. 3,042,515, 3,042,516, 3,042,517, 3,042,518, 3,042,- 519, 3,046,125, 3,056,673, and 3,082,086, the disclosures of such patents being incorporated herein by reference.

In a particular embodiment of this invention, it is preferred to use as an initiator an organic halogen compound having the formula where X, X and X" are halogens, each Y is independently selected from the group consisting of halogen, hydrogen, hydroxy, methyl and methylol, and n is selected from and 1, such that when n is O, X and X are Br. These compounds are generally more compatible and more effective with optical dye sensitizers selected from the dye and dye base form, particularly the styryl dyes and dye bases, and are preferred in such combination. Examples of such compounds are carbon tetrabromide, bromotrichloromethane, dibromodichloromethane, pentabromoethane, 2,2,2 tribromoethane and 1,1,l-tribromo 2 methyl-Z-propanol. Other examples of such compounds and combinations with styryl dyes and dye bases can be found below and in the above-noted patents to Wainer and Sprague and prior applications. In general, a Weight ratio of color former to photo-initiator of from about 1:5 to about 50:1 is satisfactory.

The color-forming agent is preferably a nitrogen atomcontaining compound having certain structural characteristics. Particularly suitable are (a) compounds having a nitrogen atom that is a member of a heterocyclic ring of up to five atoms, (b) compounds having a benzene nucleus whereby the nitrogen atom is attached to a carbon atom of such benzene nucleus and (c) N-vinyl compounds. It will be appreciated that there may be substantial overlap between the above types of nitrogen atom-containing compounds and that our invention is useful with photosensitive combinations that are formulated with compounds falling within one, two or all three of the above terms; e.g., N- vinylcarbazole. It will also be appreciated that there is no generic term available in accepted chemical terminology that will effectively embrace all of the above types of compounds. It is merely important to note that photosensitive combinations containing a compound which has at least one of the above characteristics can be readily improved by our invention. Photosensitive combinations containing compounds having more than one of the above characteristics lend themselves even better to the process; e.g., compounds of type (a) in conjugation with a benzene nucleus so that the nitrogen atom is attached to a carbon atom thereof as per compound type (b). Illustrative examples of nitrogen atom-containing compounds include N-vinylcarbazole, N-ethylcarbazole and indole.

When an N-vinyl compound and organic halogen are dispersed in a non-solubilizing continuous phase, the combination is capable of undergoing two separate and distinct reactions on exposure to actinic light. In one reaction, in a negative-working mode, a colored material is formed in light-struck areas. In another reaction, in a positive-working mode, colorless polymer is thought to be first formed and subsequent blanket exposure to stronger light, forming a color in the initially non-light-struck areas, yields a positive-working image. These two reactions are competitive, the kinetics of which say that one or the other will predominate depending on the wavelength-intensityexposure, i.e., the level of light, with the colorless polymer-forming reaction occurring with weaker light. Addition of an iodide is particularly effective in allowing the occurrence of the positive mode, non-color, reaction with extended portions of the spectrum.

In the above description of the invention, the term image is used to refer to both color and non-color images. Thus, in one sense, the term includes images which in their developed form are discernible to the eye as a result of color formation. However, the term is also being used to include images which, even in their developed state, are not necessarily discernible to the eye but which are defined by a useful change in physical or chemical properties, such as photographic sensitivity, solubility, wettability, optical turbidity, hardness, surface smoothness, and the like. The term yielding an image is used to refer to images which develop-out immediately as well as those which are only present in latent form, i.e., they are capable of being later developed either by the passage of time or by subsequent treatment with light, heat and/ or chemicals.

The following examples will illustrate various aspects of our invention.

EXAMPLE 1 A sheet of baryta paper was coated to about 3 mil wet thickness with an emulsion having the following formulation:

20% gelatin-50 ml.

1.5% Tergitol 410 drops N-vinylcarbazole4.0 g.

Carbon tetrabromide3.2 g. 4-(pdimethylaminostyryl)-quinoline-2 mg.

Ethyl acetate (saturated with Nal, about 0.01 g.)2 ml. Sodium iodide0.1 g.

The foregoing emulsion was prepared by adding the Tergitol 4 (a wetting agent) and 1 g. of sodium iodide to the gelatin, adding the N-vinylcarbazole, the 4 (p-dimethylaminostyryl)-quinoline and the carbon tetrabromide to the sodium iodide-saturated ethyl acetate and then mixing the two solutions with high speed stirring for five minutes at 40 C.

The foregoing coated sheet and a control sheet (with the same coating but omitting the sodium iodide) were exposed for 30 seconds in a Bausch & Lomb spectrograph equipped with a Hanovia watt xenon lamp as a light source. The sheets were heated for about ten seconds with a rotating drum heater at about 70 C., flooded with a Sylvania Sun Gun 11 (Model 86-55) for about one second at about 14 inches and then heated again by passing through the rotating drum heater. Positive images of the exposure were obtained. The spectral response of the control was found to extend to about 5600 A. whereas the response of the formulation containing sodium iodide was found to extend to 6200 A. (the end of the spectrograph range).

EXAMPLE 2 Emulsions were prepared having the following formulation:

20% gelatin-50 ml.

1.5% Tergitol 410 drops 37% Formalin-2 drops 5% chrome alum5 drops N-vinylcarbazole--4.0 g. Carbon tetrabromide3.2 g. Acetone-2 ml.

Sodium iodideSee below Sensitizer-See below The emulsions were prepared by adding the Tergitol 4, hardening agents (formalin and chrome alum) and sodium iodide (where present) to the gelatin, adding the N-vinylcarbazole, the sensitizer (where present) and the carbon tetrabromide to the acetone and then mixing the two solutions with high speed stirring for about five minutes at 40 C. Test sheets were then coated with the emulsion to about 3 mil wet thickness. The test sheets were exposed for 30 seconds in a Bausch & Lomb spectrograph equipped with a Hanovia 150 watt xenon lamp and a light source. They were developed by flooding with light for about two seconds from a 275 watt General Electric sun lamp at about 10 inches. This was followed by passing the test sheets through a rotating drum heater for about 10 seconds at about 66 C. The spectral response of each sheet is given in the following table which also sets forth the amount of sodium iodide and type and amount of sensitizer in each emulsion.

SENSITIZER Sodium Ethyl iodide, g. 4SQ, gJ red, g. Spectral range, A.

1 4-(p-dimethylaminostyryl)-quinoline.

EXAMPLE 3 An emulsion was prepared having the following formulation:

20% gelatin-5O ml.

1.5% Tergitol 410 drops N-vinylcarbazole4.0 g.

Carbon tetrabromide-3.2 g.

4- (p-dimethylaminostyryl) -quinoline2 mg. Ethyl acetate2 ml.

Tetrapropylammonium iodide-1 mg.

The emulsion was prepared by adding the Tergitol 4 and iodide to the gelatin, adding the N-vinylcarbazole, the 4(p-dimethylaminostyryl)-quinoline, and the carbon tetrabromide to the ethyl acetate and then mixing the two solutions with high speed stirring for about five minutes at 40 C. Test sheets were then coated with the emulsion to about 1.5 mil wet thickness. The sheets were exposed and developed in a manner similar to that set forth in Example 2. The spectral response of the sheet was found to be about 2400-6200 A.

EXAMPLE 4 Emulsions were prepared having the following formulation:

20% gelatin50 ml.

1.5% Tergitol 410 drops N-vinylcarbazole4.0 g.

Carbon tetrabromide3.2 g.

4- (p-dimethylaminostyryl -quinoline-2 mg. Ethyl acetate2 ml.

Halogen compound (see below)0.1 g.

The emulsions were prepared by adding the Tergitol 4 and halogen compound to the gelatin, adding the N-vinylcarbazole, the 4-(p-dimethylaminostyryl)-quinoline, and

Spectral Halogen compound range, A.

Test sheet:

A Sodium iodate 2,400-5,000 B. Potassium bromide 2, 4005, 000 o Lithium chloride moo-5,400

It can be seen that no advantage is gained by using an iodate, bromide or chloride in combination with a senSi tizer, in contrast to the results demonstrated in Examples 1-3.

What is claimed is:

1. In a composition comprising (1) a photosensitive dispersed phase in the form of discrete globules of a combination of (a) an aryl amine free from nuclear substitution in the position para to nuclear attachment of said amine nitrogen atom, and (b) an organic halogen compound selected from the group of compounds which produce free radicals or ions upon exposure to light of a suitable wavelength and in which there is present at least one active halogen selected from the group consisting of chlorine, bromine and iodine, attached to a carbon atom having not more than one hydrogen atom attached thereto, in (2) an aqueous dispersion medium of a solidhydrophilic-film-forming vehicle in which said dispersed phase is substantially insoluble, said composition containing (3) a photographic spectral sensitizing dye material, separate and distinct from the components of said combination, having preferential attraction for said combination and effecting a photosensitive spectral response to said combination differing from the spectral response of each of the components thereof per se and said combination in the absence of said dye material, said dye material being in a form selected from the dye form and the dye base form, the combination therewith of an iodide.

2. The invention according to claim 1 in which said iodide is selected from alkali metal and ammonium iodides.

3. The invention according to claim 1 in which said iodide is sodium iodide.

4. The invention according to claim 1 in which said iodide is potassium iodide.

5. In a composition comprising (1) a photosensitive dispersed phase in the form of discrete globules of a combination of (a) an N-vinyl compound and (b) an organic halogen compound selected from the group of compounds which produce free radicals or ions upon exposure to light of a suitable wavelength and in which there is present at least one active halogen selected from the consisting of chlorine, bromine and iodine, attached to a carbon atom having not more than one hydrogen atom attached thereto in (2) an aqueous dispersion medium of a solid-hydrophilic-film-forming vehicle in which said dispersed phase is substantially insoluble, said composition containing (3) a photographic spectral sensitizing dye material, separate and distinct from the components or said combination, having preferential attraction for said combination and effecting a photosensitive spectral response to said combination differing from the spectral response of each of the components thereof per se and said combination in the absence of said dye material, said dye material being in a form selected from the dye form and the dye base form, the combination therewith of an iodide.

6. The invention according to claim 5 in which said dye material is selected from the rhodamines, the pinacyanoles, the eosins, the triphenylmethanes, the thiazines, the anthraquinoids and the styryl dyes and dye bases.

7. The invention according to claim 5 in which said dispersion medium is selected from the group consisting of gelatin, casein, polyvinyl alcohol, gum arabic, starch, sodium carboxymethylcellulose and hydroxyethylecellulose.

8. The invention according to claim 5 in which said N- vinyl compound is capable of undergoing two separate and distinct reactions on exposure to actinic light and in the presence of said organic halogen compound.

9. The invention according to claim 5 in which said iodide is selected from alkali metal and ammonium idides.

10. The invention according to claim in which said iodide is sodium iodide.

11. The invention according to claim 5 in which said iodide is potassium iodide.

12. In a composition comprising (1) a photosensitive dispersed phase in the form of discrete globules of a combination of (a) a nitrogen atom-containing compound selected from the group consisting of N-vinyl carbazole, N-ethyl carbazole, indole and diphenylamine, and (b) an organic halogen compound selected from the group of compounds which produce free radicals or ions upon exposure to light of a suitable wavelength and in which there is present at least one active halogen selected from the group consisting of chlorine, bromine and iodine, attached to a carbon atom having not more than one hydrogen atom attached thereto in an (2) aqueous dispersion medium of a solid-hydrophilic-film-forming vehicle in which said dispersed phase is substantially insoluble, said combination being responsive to actinic light to yield an image of selective light absorptivity distinct from that of said combination and said nitrogen atom-containing compound and organic halogen compound, said composition containing (3) a photographic spectral sensitizing dye material, separate and distinct from the components of said combination, having preferential attraction for said combination and effecting a photosensitive spectral response to said combination diifering from the spectral response of each of the components thereof per se and said combination in the absence of said dye material, said dye material being in a form selected from the dye form and the dye base form, the combination therewith of an iodide.

13. In a composition consisting essentially of (1) a photosensitive dispersed phase in the form of substantially fine spheroidal solid particles of N-vinylcarbazole and carbon tetrabromide fused into a mild yellow substantially homogenous combination in (2) an aqueous, substantially translucent continuous solid-hydrophilic-filmforming-phase in which the dispersed phase is substantially insoluble, said combination being selectively photoreactive to produce a coloring agent and to produce a photoinsensitive agent of substantially the same visible appearance as said photosensitive combination, said composition containing (3) a photographic spectral sensitizing dye material, separate and distinct from the components of said combination, having preferential attraction for said combination and effecting a photosensitive spectral response to said combination, differing from the spectral response of each of said components per se and said combination in the absence of said dye material, said dye material being in a form selected from the dye form and dye base form, the combination therewith of an iodide.

14. In a composition consisting essentially of (1) a photosensitive dispersed phase in the form of substantially fine spheroidal solid particles of N-vinylcarbazole and hexachloroethane fused into a substantially colorless homogeneous combination in (2) an aqueous, substantially translucent continuous solid-hydrophilic-film-forming phase in which the dispersed phase is substantially insoluble, said combination being selectively photo-reactive to produce a coloring agent and to produce a photo-insensitive agent of substantially the same visible appearance as said photosensitive combination, said composition containing (3) a photographic spectral sensitizing dye material, separate and distinct from the components of said combination, having preferential attraction for said combination and efiecting a photosensitive spectral response to said combination differing from the spectral response of each of the components thereof per se and said combination in the absence of said dye material, said dye material being in the form selected from the dye form and the dye base form, the combination therewith of an iodide.

15. In a combination which is photosensitive in a hydrophilic binder, comprising (1) an organic halogen compound having the formula wherein X, X and X are halogens, each Y is independently selected from the group consisting of halogen, hydrogen, hydroxy, methyl and methylol, and n is selected from O and 1, such that when n is O, X and X are Br, (2) an aromatic amine, and (3) a styryl dye material in a form selected from the dye form and dye base form, the combination therewith of an iodide.

16. The invention according to claim 15 in which said iodide is selected from alkali metal and ammonium iodides.

17. The invention according to claim 15 in which said iodide is sodium iodide.

18. The invention according to claim 15 in which said iodide is potassium iodide.

19. The invention according to claim 15 in which said styryl dye or dye base is 4-(p-dimethylaminostyryl)-quinoline dye or dye base.

20. The invention according to claim 15 in which said styryl dye material is in the dye base form.

21. The invention according to claim 20 in which said aromatic amine is an N-vinyl compound.

22. The invention according to claim 21 in which said N-vinyl compound is N-vinylcarbazole and said organic halogen is carbon tetrabromide.

23. The invention according to claim 22 in which said styryl dye or dye base is 4-(p-dimethylaminostyryl)- quinoline dye or dye base.

References Cited UNITED STATES PATENTS 2,099,297 11/1937 Clement 96-48 3,042,518 7/1962 Wainer 96--90X NORMAN G. TORCHIN, Primary Examiner R. E. FIGHTER, Assistant Examiner US. Cl. X.R. 9688