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Publication numberUS3245790 A
Publication typeGrant
Publication dateApr 12, 1966
Filing dateNov 13, 1961
Priority dateNov 13, 1961
Publication numberUS 3245790 A, US 3245790A, US-A-3245790, US3245790 A, US3245790A
InventorsJohn F Downey, Myron S Simon
Original AssigneePolaroid Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Novel photographic products, processes and compositions
US 3245790 A
Images(5)
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Description  (OCR text may contain errors)

United States Patent 3,245,790 NOVEL PHOTOGRAPHIC PRODUCTS, PROCESSES AND COMPOSITIONS John F. Downey, Burlington, and Myron S. Simon, Newton Center, Mass., assignors to Polaroid Corporation, Cambridge, Mass, a corporation of Delaware No Drawing. Filed Nov. 13, 1961, Ser. No. 152,014 13 Claims. (Cl. 96-29) This invention relates to photography and more particularly to products, compositions and processes for the development of photosensitive silver halide elements.

lit is one object of the present invention to provide novel processes and compositions for the development of silver halide emulsions, in which novel colored developing agents are used.

Another object is to provide novel processes and compositions for the development of silver halide emulsions, in which the novel developing agent is capable of developing an exposed silver halide emulsion and imparting a reversed or positive colored image of the developed image to a superposed image-receiving material.

A further object is to provide novel products, processes and compositions suitable for use in preparing monochromatic and multichromatic photographic images.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the processes involving the several steps and the relation and order of one or more of such steps with respect to each of the others, and the products and compositions possessing the features, properties and the relation of elements which are exemplified in the following detailed disclosure, and the scope of the application of which Will be indicated in the claims.

The objects of this invention may be accomplished by the use of certain novel dyes which have the ability to develop images present in an exposed silver halide emulsion; thus they may be referred to as dye developers. These novel dyes or dye developers will be further described hereinafter.

The photographic processes and compositions disclosed herein are particularly useful in the treatment of a latent image present in a photosensitive element, such as an exposed silver halide emulsion, whereby a positive dye image thereof may be imparted to another element, herein referred to as an image-carrying or image-receiving element.

US. Patent No. 2,983,606, issued May 9, 1961, to Howard 6-. Rogers, discloses diffusion transfer reversal processes wherein a photographic negative material, such as a photographic element comprising an exposed silver halide emulsion, is developed in the presence of a dye developer to impart to an image-receiving layer a reversed or positive dye image of the developed image by permeating into said emulsion a suitable liquid processing composition and bringing said emulsion into superposed relationship with an appropriate image-receiving layer. The inventive concepts herein set forth provide novel dye developers for use in such processes.

In carrying out the process of this invention, a photosensitive element containing a silver halide emulsion is exposed and wetted with a liquid processing composition, for example, by immersing, coating, spraying, flowing, etc., in the dark, and the photosensitive element superposed, prior to, during or after Wetting, on an imagereceiving element. In a preferred embodiment, the photosensitive element contains a layer of dye developer, and the liquid processing composition is applied to the photosensitive elem-ent in a uniform layer as the photosensitive element is brought into superposed position with an imagereceiving element. The liquid processing composition permeates the emulsion to provide a solution of dye developer substantially uniformly distributed therein. As the exposed silver halide emulsion is developed, the oxidation product of the dye developer is immobilized or precipitated in situ with the developed silver, thereby providing an imagewise distribution of unoxidized dye developer dissolved in the liquid processing composition. This immobilization is apparently due, at least in part, to a change in the solubility characteristics of the dye developer upon oxidation, and especially as regards its solubility in alkaline solutions. It may also be due, in part, to a tanning effect on the emulsion by the oxidized developing agent. At least part of this imagewise distribution of unoxidized dye developer is transferred, by imbibition, to a superposed image-receiving layer, said transfer substantially excluding silver or oxidized dye developer. The image-receiving layer receives a depthwise diffusion, from the emulsion, of unoxidized dye developer, without appreciably disturbing the imagewise distribution thereof, to provide a reversed or positive, colored image of the developed or negative image. The image-receiving element may contain agents adapted to mordant or otherwise fix the diffused, unoxidized dye developer. Imbibition periods of approximately one minute have been found to give good results, but this contact period may be adjusted where necessary to compensate for variations in temperature or other conditions. The desired positive image is revealed by separating the image-receiving layer from the photosensitive element at the end of the imbibition period.

The dye developers of this invention may be utilized in the photosensitive element, for example in, on or behind the silver halide emulsion, or they may be utilized in the image-receiving element or in the liquid processing composition. In a preferred embodiment, a coating or layer of the dye developer is placed behind the silver halide emulsion, i.e., on the side of the emulsion adapted to be located most distant from the photographed subject when the emulsion is exposed and preferably also adapted to be most distant from the image-receiving layer when in superposed relationship therewith. Placing the dye developer behind the emulsion layer, as in the preferred embodiment, has the advantage of providing increased contrast in the positive image, and also minimizes any lightfiltering action by the colored dye developer. In this preferred embodiment, the layer of dye developer may be applied by using a coating solution containing, e.g., about 0.5 to 8%, by weight, of the dye developer. Similar concentrations may be used if the dye developer is utilized as a component of the liquid processing composition. In an especially useful mode of disposing the dye developers in the photosensitive elements, the dye developer is dissolved in a water-immiscible solvent and then dispersed in a gelatin coating solution.

The liquid processing composition which is used in the processes herein disclosed comprises at least an aqueous solution of an alkaline compound, for example, diethylamine, sodium hydroxide or sodium carbonate, and may contain the dye developer. In some instances, it may contain an additional silver halide developing agent. If the liquid processing composition is to be applied to the emulsion by being spread thereon, preferably in a relatively thin, uniform layer, it may also include a viscosity-increasing compound constituting film-forming material of the type which, when spread over a water-absorbent base, will form a relatively firm and relatively stable film. A preferred film-forming material is a high molecular weight polymer such as a polymeric, water-soluble ether inert to an alkali solution, as, for example, a hydroxyethyl cellulose or sodium carboxymethyl cellulose. Other filmforming materials or thickening agents whose ability to 3 increase viscosity is substantially unaffected when left in solution for a long period of time may also be used.

The novel dye developers of this invention are anthraquinone dyes having the formula wherein R is an alkylene or alkoxy group, R is an alkylene group and Z is an orthoor para-dihydroxyphenyl radical.

As examples of alkylene radicals comprehended by R and R mention may be made of radicals such. as 2, 2 2, 2)s 2)4, z-)5,

Y a 02115 C H2C Hand-Hr-CH When R is an alkylene group, it is intended that alkylene include an intralinear cyclic component, e.g.,

In a preferred embodiment, R is an alkylene group containing between 2 and 10 carbons, and more preferably 3 to 7 carbons. R is preferably an alkylene group comprising l to 4 carbons and more preferably a methylene or ethylene group. It should be understood that R may be an alkylene group comprising 10 or more carbons, and R may be an alkylene group comprising 4 or more carbons, providing that the resulting dye developer is capable of being dissolved in the liquid processing composition described herein and its oxidation product rendered immobile. Z is preferably a para-dihydroxyphenyl radical.

It should be understood that, when desired, the anthraquinone nucleus may be substituted by one or more other substituents such as amino, alkyl, aryl, halogen, alkylamino, aryloxy, alkoxy, hydroxyl, sulfonamido, alkylsulfonamido, arylsulfonamido, carboxamido, carboxyl or sulfo radicals. It will be understood that when the anthraquinone nucleus is substituted with a carboxyl, sulfo, or other solubilizing group, care should be taken in selecting other substituents and processing conditions so that the oxidized dye developer will be less mobile in the processing composition than the unoxidized dye developer.

The dye developer within Formula 1 may be prepared by condensing an anthraquinone of the formula:

( O ITIHz O NH:

wherein R has the same meaning as above, witha compound of the formula: I?

Z -R OC1 wherein R has the same meaning as above and Z is the protected derivative, preferably, the acyl derivative and, more preferably, the bis-acetoxy derivative of the orthoand para-dihydroxyphenyl radical, and removing the protective groups, as by hydrolysis. This method of preparation is particularly useful in preparing compounds within Formula 1 wherein R comprises more than 2 carbons.

When R is one or two carbons, the compounds within Formula 1 may be conveniently prepared by reacting one mole of a compound within Formula 2 with one mole of a compound of the formula:

O l I (0H2).

I OH

wherein n is an integer from 1 to 2.

In addition to the homogentisic acid lactones within Formula 4, the dye developers of this invention may also be prepared by reacting gentisic acid lactones and the substituted derivatives thereof with a compound within Formula 2.

Compounds within Formula 4 and the substituted derivatives thereof may be prepared according to the synthesis disclosed in the copending application of Samuel Dershowitz, Serial No. 147,761, filed October 26, 1961 (now abandoned).

Compounds within Formula 2 may be prepared by reacting 1,4 diamino 2 phenoxyanthraquinone with an amino-alcohol according to the method disclosed in US Patent No. 1,943,876, issued January 16, 1934, wherein an alcohol is reacted with l,4-diamino-Z-phenoxyanthraquinone.

As examples of amino-alcohols that are useful in this preparation to provide compounds wherein R is alkylene or alkoxy, mention may be made of:

no-cm-Qo Hz-NH2 no-or-r In particular, the dye developers of this invention provide highly useful magenta dye developers which have been found to possess outstanding light stability characteristics in a finished photographic print, and are substantially more light stable than many azo and other anthraquinone magenta dye developers. When utilized in the diffusion transfer process, the dye developers of this invention are found to possess good transfer characteristics and give high density images.

Although Z has been described as an orthoor paradihydroxyphenyl radical, it should be understood that in certain instances one may desire to use other silver halide developing radicals to provide the silver halide developing function in the dye developer, for example, a dih-ydroxysubstituted naphthalene radical. It should also be understood that the radical Z may contain swbstituents other than those which. supply the silver halide developing ability; such substituents include alkyl, alkoxy, hydroxy, halogen, etc., groups.

Where a compound of Formula 3 is used in the synthesis, it may be desirable to protect the hydroxyl groups, which supply the developing function possessed by Z, by acylation, for example, to avoid side reactions or oxidation. The protective groups are removed, as by hydrolysis, prior to photographic use.

As examples of dye developers within the scope of this invention, mention maybe made of 1,4-diamin0-2- fl-homogentisamido) -ethoxy-anthraquinone 11 o N112 OH II I (H) I 0 NHz orr 1,4-diamino-2-['y-(2,'5'dihydroxy) -hydrocinnamido] amoxy-anthraquinone 1,4-diamino-2- [B- ('y [2 -dihydr0xy] -hydrocinnamid0) propyl -eth0xy-anthraquinone O NH;

1,4-diarnino-2- ['y 2,5 -tlihydroxy) -hydrocinnamid0] propoxy-anthraquinone The following nonlimiting examples illustrate the preparation of dye developers within the scope of this invention.

Example I A liter flask was charged with 34.9 grams of 1,4- diaminc-2-(e-amino)-amoxy-anthraquinone, 29.4 grams of 2,S-dihydroxyhydrocinnamic acid lactone and 350 cc. of alcohol. The flask was fitted with a condenser and Bunsen valve, deaerated with nitrogen and the contents heated 16 hours on the steambath. The mixture was then cooled to 25 C., and a deaerated solution of 13.5 grams of sodium hydroxide was added to the flask. The flask was then filled with deaerated water and allowed to stand 30 minutes. Canbon dioxide was bubbled in until no further change of pH occurred. The mixture was then filtered and washed with 3% hydrochloric acid until the filtrate was colorless. The solid was then washed with water until acid-free. The solid was recrystallized from isopropyl alcohol. The resulting 1,4-diamino-2-[y-2,5-dihydroxy)- hydrocinnamido]-amoxy anthraquinone melted at 157- 158 C. and had a spectral absorption curve A at 577; e=16,000.

Example II 1,4-diarnino-2-(B-homogentisamido)-eth-oxy anthraquinone was prepared according to the procedure of Example I using 1,4-diamino-2-(fi-amino)-ethoxy anthraquinone 6 and 2,5-dihydroxyhydrocinnamic acid lactone. uct melted at 178-184 C.

Example III 1,4-diamino-2-[y-(2,5-.dihydroxy) -hydrocinnamido] propoxy anthraquinone was prepared according to the procedure of Example I using l,4-diamino-2-(ot-amino)- propo-xy anthraquinone and 2,5-dihydroxyhydrocinnamic acid lactone. The product melted at 141144 C.

Example IV 1,4-dia1nino-2-[fl-(2',5-dihydroxy) hydro'cinnamido B-ethyl]-ethoxy anthraquinone was prepared according to the procedure of Example I using 1,4-diamino-2-(/3- amino)-,8-ethyl-ethoxy anthraquinone and 2,5-dihydroxyhydrocinnamic acid lactone. The product melted at 124- 134 C.

The following examples of the photographic utilization of the dye developers of this invention are given for purposes of illustration only.

The prod- Example V A photosensitive element was prepared by coating a gelatin subcoated film base with a solution comprising 0.38 g. of 1,4-diarnir1o-2-[ y-(2,5'-dihydroxy)-hydrocinnamido]-amoxy-anthraquin0ne dissolved in 10 cc. of a solution of 2% cellulose acetate hydrogen phthalate in acetone. After this coating dried, a blue-sensitive silver iodo bromide emulsion was applied and allowed to dry. This photosensitive element was exposed, and brought into superposed relationship with an image-receiving element as an aqueous liquid composition comprising:

Water cc NaOI-I g 5.17 Hydroxyethyl cellulose (high viscosity) [commercially available from Hercules Powder Co., Wilmington 99, Delaware, under the trade name Natrosol 250] g 4.03 Sodium thiosulfate g 1.15 Benzotriazole g 2.3' N benzyl-a-picolinium bromide g 2.3

was spread between said elements. The image-receiving element comprised a 2:1 mixture, by weight, of polyvinyl alcohol and poly-4-vinylpyridine on a baryta paper support. After an imbibition period of approximately one minute, the image-receiving element was separated and contained a magenta positive image.

Example VI The procedure described in Example V was repeated, except that the dye developer was dispersed in a layer of gelatin. The coating solution from which the dye developer layer was coated was prepared by adding 0.57 g. of the dye developer dissolved in 1.5 cc. of N-n-butylacetanilide and 2 cc. of cyclohexanone to 5 g. of 10% gelatin solution, 1.3 cc. of water at 40 C., and 1 cc. of 5% Alkanol B. Emulsification was effected by high speed agitation in a Waring blendor. 5 cc. of the resulting dye dispersion was added to 10 cc. of water containing small amounts of saponin and succinaldehyde, and then coated on the gelatin subooated cellulose acetate film base.

Substitution of the other dye developers described above in the procedures described in Examples V and VI gave similar positive transfer images.

It has been found that if the dye developers of this invention contain some of the anthraquinone triamine intermediate dyes, desensitization of the silver halide emulsion may occur if the emulsion is in contact with a layer containing the dye developer. Accordingly, precautions should be taken to remove unreacted anthraquinone triamine prior to photographic use. Also, known procedures for handling dyes which exhibit a tendency to desensitize may be used.

The dye developers of this invention are also useful in integral multilayer photosensitive elements for use in multicolor diffusion transfer processes. As an example of such photosensitive elements, mention may be made of the photosensitive elements disclosed and claimed in the copending US. application of Edwin H. Land and Howard G. Rogers, Serial No. 565,135, filed February 13, 1956, wherein at least two selectively sensitized photosensitive strata are superposed on a single support and are processed, simultaneously and without separation, with a single common image-receiving element. A suitable arrangement of this type comprises a support carrying a red-sensitive silver halide emulsion stratum, a greensensitive silver halide emulsion stratum and a blue-sensitive silver halide emulsion stratum, said emulsions having associated therewith, respectively, a cyan dye developer, a magenta dye developer and a yellow dye developer. In one of the preferred embodiments of photosensitive elements of this type, the dye developers are disposed in separate alkali-permeable layers behind the photosensitive silver halide emulsion stratum with which they are associated.

The photosensitive elements within the scope of this invention may be used in roll film units which contain a plurality of photosensitive frames. The photosensitive elements of this invention are especially useful in composite roll film intended for use in a Polaroid Land Camera, sold by Polaroid Corporation, Cambridge 39, Massachusetts, or a similar camera structure such, for example, as the camera forming the subject matter of US. Patent No. 2,435,717, issued to Edwin H. Land on February 10, 1948. In general, such composite roll films comprise a photosensitive roll, a roll of image-receiving material and a plurality of pods containing an aqueous alkaline processing solution. The rolls and pods are so associated with each other that, upon processing, the photosensitive element may be superposed on the imagereceiving element and the pods may be ruptured to spread the aqueous alkaline processing solution between the superposed elements. The nature and construction of the pods used in such units are well known to the art. See, for example, US. Patents Nos. 2,543,181 and 2,634,886, issued to Edwin H. Land.

It will be noted that the liquid processing composition may contain one or more auxiliary or accelerating silver halide developing agents, such as p-methylaminophenol (Metol); 2,4-diaminophenol (Amidol); benzylaminophenyl; hydroquinone; a substituted hydroquinone such as tolnhydroquinone, phenylhydroquinone, or 4'-methylphenylhydroquinone; or a 3-pyrazolidone such as 1-phenyl-3- pyrazolidone. These auxiliary silver halide developing agents are substantially colorless, at least in their unoxidized form. It is possible that some of the dye developer oxidized in exposed areas may be oxidized by an energy transfer reaction with oxidized auxiliary silver halide developing agent.

In addition, development may be effected in the presence of an onium compound, particularly a quaternary ammonium compound, in accordance with the processes disclosed and claimed in the copending application of Milton Green and Howard G. Rogers, Serial No. 50,851, filed August 22, 1960 (now US. Patent No. 3,173,786, issued March 16, 1965.

The dye developers of this invention may be used also in conventional photograpihc processes, such as tray or tank development of conventional photosensitive films, plates or papers to obtain black and white, monochromatic or toned prints or negatives. By way of example, a developer composition suitable for such use may comprise an aqueous solution of approximately 12% of the dye developer, 1% sodium hydroxide, 2% sodium sulfite and 0.05% potassium bromide. After development is completed, any unreacted dye developer is washed out of the photosensitive element, preferably with an alkaline washing medium or other medium in which the unreacted dye developer is soluble. The expression toned is used to designate photographic images wherein the silver is retained with the precipitated dye, whereas monochromatic is intended todesignate dyeimages free of silver.

It should be noted that the dye developers of this medium are self-sufficient to provide the desired color image and do not depend upon coupling reactions to produce the desired color. .They thus provide a complete departure from conventional photographic color processes in which the color is produced by a coupling reaction between a color former or coupler and the oxidized developing agent, as well as so-called auto-coupling processes in which color is obtained by a reaction of the oxidized developing agent with unoxidized developing agent.

It will be apparent that, by appropriate selection of the image-receiving element from among suitable known opaque and transparent materials, it is possible to obtain either a colored positive reflection print or a colored positive transparency. Likewise, the inventive concepts herein set forth are adaptable for multicolor work by the use of special photographic materials, for example, film materials of the type containing two or more photosensitized elements associated With an appropriate number of image-receiving elements and adapted to be treated with one or more liquid processing compositions, appropriate dye developers suitable to impart the desired subtractive colors being incorporated in the photosensitive elements or in the liquid processing compositons. Examples of such photographic materials are disclosed in US. Patent No. 2,647,049 issued to Edwin H. Land on July 28, 1953.

As examples of useful image-receiving materials, mention may be made of nylon, e.g., N-methoxymethyl-polyhexamethylene adipamide, polyvinyl alcohol, and gelatin, particularly polyvinyl alcohol or gelatin containing a dye mordant such as poly-4-vinylpyridine.

The image-receiving elementalso may contain a development restrainer, e.g., 1-phenyl-5-mercaptotetrazole, as disclosed in the copending application of Howard G. Rogers and Harriet W. Lutes, Serial No. 50,849, filed August 22, 1960.

The inventive concepts herein set forth are also adaptable for the formation of colored images in accordance with the photographic products and processes described and claimed in US. Patent No. 2,968,554 issued to Edwin H. Land on January 17, 1961.

The novel compounds herein disclosed are also suitable for use as dyes for textile fibres, such as nylon.

In the preceding portions of the specification the expression color has been frequently used. This expresslon is intended to include the use of a plurality of colors to obtain black.

Since certain changes may be made in the above products, compositions and processes without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A process of forming a photographic image in color, comprising developing an exposed silver halide emulsion in the presence of an aqueous alkaline solution comprising a dye developer of the formula:

wherein R is selected from the group consisting of alkylene and alkoxy groups, R is an alkylene group and Z is selected from the group consisting of orthoand paradihydroxyphenyl radicals, to thereby provide an imagewise distribution of unoxidized dye developer, and transferring at least a part of said imagewise distribution of unoxidized dye developer by imbibition to an imagereceiving layer in superposed relationship with said silver halide emulsion to impart a dye image to said imagereceiving layer.

2. A process as defined in claim 1, wherein said dye developer is disposed, prior to exposure, in the photosensitive element comprising said exposed silver halide emulsion, and the solution containing said dye developer is formed by permeating said photosensitive element with an aqueous alkaline liquid capable of solubilizing said dye developer.

3. A process as defined in claim 2., wherein said liquid is introduced by being spread in a substantially uniform layer as said photosensitive element and image-receiving layer are brought into superposed relationship.

4. A process as defined in claim 2, wherein said liquid contains a thickener for increasing viscosity and for facilitating the spreading thereof between said photosensitive element and said image-receiving layer.

5. A process as defined in claim 2, wherein said aqueous alkaline solution contains a silver halide developing agent which is substantially colorless in at least its unoxidized form.

6. A process as defined in claim 1, wherein R and R are alkylene radicals and Z is a para-dihydroxyphenyl radical.

7. A process as defined in claim 1, wherein said dye developer is 1,4-diamino-2-(fi-homogentisamido)-ethoxy anthraquinone.

8. A process as defined in claim 1, wherein said dye developer is 1,4-diamino-2-['y-(2,5-dihydroxy)-hydrocinnamido]-amoxy anthraquinone.

9. A process as defined in claim 1, wherein said dye dveloper is 1,4-diamino-Z-['y-(2,5'-dihydroxy)-hydrocinnamido]-propoxy anthraquinone.

10. A process as defined in claim 1, wherein said dye developer is 1,4-diamino-2-[/3-(2',5-dihydroxy)-hydrocinnamido-B-ethyl] -ethoxy anthraquinone.

11. A photographic product comprising a support carrying on the same side thereof a layer containing a silver halide emulsion, and a layer containing a dye developer of the formula:

NHI

I l O wherein R is selected from the group consisting of alkylene and alkoxy groups, R is an alkylene group and Z is selected from the group consisting of orthoand para-dihydroxyphenyl radicals.

13. A photographic developer composition comprising an aqueous alkaline solution of a silver halide developing agent which is substantially colorless in at least its unoxidized form and a dye developer of the formula:

II @T/ wherein R is selected from the group consisting of alkylene and alkoxy groups, R is an alkylene group and Z is selected from the group consisting of orthoand para-dihydroxyphenyl radicals.

References Cited by the Examiner UNITED STATES PATENTS 1,943,876 1/ 1934 Nawiasky 260-380 1,964,971 7/1934 Albrecht 260380 2,983,605 5/1961 Corley 9629 2,983,606 5/ 1961 Rogers 9629 NORMAN G. TORCHIN, Primary Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1943876 *May 1, 1931Jan 16, 1934Gen Aniline Works IncProduction of anthraquinone derivatives
US1964971 *Nov 5, 1931Jul 3, 1934Gen Aniline Works IncAlkyl ethers of amino-betahydroxyanthraquinones
US2983605 *Jan 31, 1955May 9, 1961Polaroid CorpPhotographic products, processes, and compositions
US2983606 *Jul 14, 1958May 9, 1961Polaroid CorpProcesses and products for forming photographic images in color
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3963763 *Oct 9, 1974Jun 15, 1976Bayer AktiengesellschaftAnthraquinone dyestuffs
US4199354 *Dec 20, 1974Apr 22, 1980Eastman Kodak CompanyBallasted image-dye providing materials
US4199355 *Jun 24, 1975Apr 22, 1980Eastman Kodak CompanyPositive-working immobile photographic compounds and photographic elements containing same
US4278598 *Sep 1, 1976Jul 14, 1981Eastman Kodak CompanyPositive-working immobile intramolecular nucleophilic displacement compounds and photographic elements containing same
USRE29577 *Jan 4, 1977Mar 14, 1978Bayer AktiengesellschaftAnthraquinone dyestuffs
Classifications
U.S. Classification430/243, 430/225, 430/559, 430/390, 430/467
International ClassificationG03C8/18, C09B1/54
Cooperative ClassificationC09B1/545, G03C8/18
European ClassificationC09B1/54D, G03C8/18