Photographic Element, Composition And Process

Abstract

Photographic elements, compositions and processes employing certain stable sources of metal for physical development, including certain metal-organic complexes, such as metal-thiazoline thione or metal-thiazolidine thione complexes or metal-alkyne complexes, provide good images. Silver-dye complexes are especially suitable as a photosensitive material for use with these metal-organic complexes, typically silver-organic complexes.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is directed to photographic elements, compositions and processes employing physical development in obtaining a desired image. In one of its aspects, it relates to photographic elements, compositions and processes employing certain stable sources of metal for physical development including certain metal-organic complexes, especially certain silver-organic complexes. In another of its aspects, it relates to photographic elements, compositions and processes employing a silver-dye complex which has the property of forming active sites for physical development upon exposure to radiation in combination with the described silver-organic complexes as stable sources of silver for physical development.

2. Description of the Prior Art

Radiation-sensitive coatings based on silver, especially photographic silver halides, and physical development of such coatings, are well known, as described, for example, in Mees, The Theory of the Photographic Process, Third Edition, (1966) and British Patent 936,609 issued Sept. 11, 1963. Spectral sensitization of photographic silver halides by addition thereto of a sensitizing dye is also well known. Further, a reaction product, identified as a silver-dye complex of a dye and a water-soluble silver salt, e.g., silver nitrate, which complex is photosensitive is described in French Patent 1,453,635 issued Aug. 16, 1966. A photographic silver halide emulsion which is mixed with such a silver-dye complex has its spectral sensitivity extended into the region of the absorption of the dye. Such silver-dye complexes can be a photosensitive medium in the absence of silver halide, so that energy absorbed by the dye upon exposure is used directly to form sites for physical development. This is disclosed, for example, in French Patent 1,453,635 issued Aug. 16, 1966.

However, the sources of metal, especially silver, for such physical development have not been entirely satisfactory. In many cases they have either been too unstable, releasing the metal at an undesired time, or caused undesired fog and stain. For example, while a silver-thiosulfate complex can be employed as a source of silver for physical development of an image in a photosensitive coating containing a silver-dye complex as the photosensitive material, as described, for example, in French Patent 1,453,635, a silver-thiosulfate complex can produce undesired fog and produce other undesired effects. A silver complex of 4,5-(2,3-D-fructopyrano)-2-oxazolidinethione also has these disadvantages. Accordingly, while sources of silver have been employed for physical development in the described photographic systems, they have not produced desired results in many cases.

Further, there has been a need for sources of silver for physical development which provide desired concentrations of silver ion in particular photographic systems, especially systems employing a silver-dye complex as a photographic component, i.e., desired pAg levels, while providing desired sensitometric properties.

It is accordingly an object of the present invention to provide a photographic element, composition and process, employing an improved stable source of metal, especially silver, for physical development providing desired sensitometric properties.

Another object is to provide a photographic element containing a silver-dye complex capable of forming sites for physical development upon exposure to radiation and containing an improved stable source of metal, especially silver, for physical development of such sites, which is a stable metal-organic complex providing desired sensitometric properties.

Another object is to provide a photographic process for physical development of a latent image in a radiation sensitive metal salt employing an improved stable source of metal for the described physical development.

A further object is to provide a photographic composition, such as a photographic emulsion or developer composition, containing an improved stable source of metal for physical development as described.

Additional objects and advantages will be apparent from the following description and claims.

SUMMARY OF THE INVENTION

According to the invention improved elements, especially photographic elements, processes and compositions are provided which are suitable for physical development, especially photographic elements, processes and compositions employing a photographic silver-dye complex and are resistant to undesired fog and/or stain by employing an improved stable source of metal for physical development which is a stable metal-organic complex of (a) a metal suitable for physical development with (b) a compound which is:

a. a thioamide, including

i. A thiazoline thione and/or thiazolidine thione,

ii. A thiopyrimidine,

iii. An oxazolidine-2-thione,

iv. A dithiocarbamate, and/or

v. A thiourea derivative, and/or

b. a guanyl compound, including

i. A pseudothiohydantoin,

ii. An imidazolidine,

iii. An imidazoline, and/or

iv. An isothiourea derivative, and/or

c. a mercapto acid, including

i. A mercaptocarboxylic acid, and/or

ii. A mercaptoaxetyl amide, and/or

d. an alkyne compound, and/or

e. a hydroxyalkyl carboxylic acid and/or a hydroxy heterocyclic carboxylic acid, and/or

f. a thiaalkyl compound, including a dithiaalkyl and/or oligothiaalkyl compound, and/or

g. oxalic acid, a phenylene dioxy dialkyl carboxylic acid, and/or succinic acid, and/or

h. a polymer containing a ligand atom having the property of complexing a metal suitable for physical development including

i. Polymers wherein the described ligand atom is sulfur, such as

1. Polymers containing thiaalkyl acrylamide units and/or methacrylamide units, and/or

2. Polymers containing thiaalkyl acrylate units and/or methacrylate units.

Also, a stable complex of silver with the described polymers according to the invention can provide other desired properties, such as eliminating part of the binder in a photographic emulsion.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The described metal-organic complexes are especially advantageous in photographic elements, processes and compositions wherein the metal for physical development is silver and the described stable metal-organic complex is a stable silver-organic complex.

The described stable metal-organic complexes can be employed in a wide range of elements, especially photographic elements, processes and compositions. They can be employed in any photographic element, process or composition where it is desirable to employ a stable metal complex as a stable source of metal, especially silver, for physical development. Various types of photographic elements, processes and compositions, where it is desirable to have a stable source of metal for physical development, are known.

These are described, for example in Mees, The Theory of the Photographic Process, Third Edition (1966), pages 324-331, in British Patent 936,609 issued Sept. 11, 1963 and in French Patent 1,453,635 issued Aug. 16, 1966. The described metal-organic complexes are especially suitable in a photographic element, process and/or composition employing, as a radiation sensitive component, a silver-dye complex which has the property of forming active sites for physical development upon exposure to radiation, as described in French Patent 1,453,635 issued Aug. 16, 1966. The following dyes are representative merocyanine dyes which can be used to form the described radiation sensitive silver-dye complexes:

a. 3-carboxymethyl-5[(3-methyl-2-thiazolidinylidene)-ethylidene]rhodanine 420-560 m.mu.;

b. 5-[(3-methyl-2-thiazolidinylidene)ethylidene]rhodanine 460-570 m.mu.;

c. 5-[(3-methyl-2-thiazolidinylidene)ethylidene]-2-thio-2,4-oxazolidinedione 400-560 m.mu.;

d. 3-ethyl-5-[(3-methyl-2-thiazolidinylidene)ethylidene]-2-thio-2,4-oxazolidi nedione 430-540 m.mu.;

e. 1-methyl-5[(3-methyl-2-thiazolidinylidene)ethylidene]-2-thiobarbituric acid 430-530 m.mu.;

f. 3-carboxymethyl-5-[(3-ethyl-2-benzoxazolinylidene)-ethylidene]rhodanine 420-580 m.mu.;

g. 5-(3-ethyl-2-benzoxazolinylidene 370-460 m.mu.;

h. 5-[(3-ethyl-2-benzoxazolinylidene)ethylidene]rhodanine 520-560 m.mu.;

i. 3-ethyl-5-[(3-ethyl-2-benzoxazolinylidene)ethylidene]-1-phenyl-2-thiohydan toin 520-560 m.mu.; and

j. 1-carboxymethyl-5-[(3-ethyl-2-benzoxazolinylidene)-ethylidene]-3-phenyl-2- thiohydantoin 520-560 m.mu..

Various dyes, other than merocyanine dyes can be employed as the dye moiety in the described silver-dye complex, including known silver halide sensitizing dyes, such as cyanines, oxonols, hemicyanines, styryls, hemioxonols, benzylidenes, and the like, examples of which are set out in the described Mees reference, pages 198-232.

These silver-dye complexes can be prepared typically by mixing the dyes with a water-soluble silver salt, such as silver nitrate, in a suitable solvent, e.g., water, or can be prepared in a radiation sensitive coating composition in situ without separation or recovery of the silver-dye complex from the coating composition, such as by mixing the desired components in the coating composition before application to a support using techniques well known in the photographic art.

One embodiment of the invention is an element, especially a photographic element comprising a photographic component which is the main photographic component of the desired element and a stable source of metal for physical development, especially a stable source of silver, which is a stable metal-organic complex, preferably a silver-organic complex as described.

An especially useful embodiment is a photographic element comprising a support having thereon a radiation-sensitive silver-dye complex, as described, which has the property of forming active sites for physical development upon exposure to radiation, and a stable source of metal for physical development which is a stable metal-organic complex as described.

The described stable source of metal for physical development according to the invention can be in any location in and/or on the photographic element and/or in a processing composition which provides the desired physical development activity without undesired fog and stain. It can be, for example, in a radiation-sensitive coating and/or an overcoat and/or a coating between the support and a radiation-sensitive coating or some other coating or combination of coatings. It can be in one or more coatings of a receiver sheet employed in a diffusion transfer process and/or in a photographic element and/or processing composition employed in a diffusion transfer process.

While silver is a preferred metal moiety of the described stable metal-organic complexes employed in the invention, other metals which are useful in physical development can be employed. Metals which are members of the electromotive scale below hydrogen are those most commonly employed for this purpose, such as copper, mercury, palladium, platinum, gold, silver, and the like.

A stable source of metal for physical development which is a stable metal-organic complex of (a) a metal suitable for physical development with (b) a thioamide according to the invention is represented by the following formula:

wherein M is a metal suitable for physical development, such as silver, copper, mercury, palladium, platinum, gold, and the like; R.sub.1 and R.sub.2 are the same or different and each is hydrogen, alkyl, alkylene, acyl, or aryl; R.sub.3 is alkyl, --S--R.sub.4, or --O--R.sub.4, or

, wherein R.sub.4 and R.sub.5 are hydrogen, alkyl, alkylene, acyl or aryl; and corresponding tautomeric compounds, such as wherein R.sub.1 is hydrogen:

any two R groups can, but need not, be joined to form a heterocyclic ring as represented by the broken lines in structure I.

Alkyl suitably contains one to about 20 carbon atoms, typically one to five carbon atoms, such as methyl, ethyl, propyl butyl, pentyl, decyl and eicosyl. Alkylene suitably contains one to about five carbon atoms, such as methylene, ethylene, propylene, butylene and pentylene. Acyl can be:

wherein alkyl is as described, especially alkyl containing one to five carbon atoms.

Aryl suitably contains six to about 30 carbon atoms, such as phenyl, tolyl, xylyl and naphthyl. The described alkyl, alkylene, acyl and aryl can contain various substituent groups which do not adversely affect the stability and availability of metal for physical development of the described complexes and compounds. Suitable substituent groups include for example, carboxyl, hydroxyl and sulfonic acid groups. Such groups can provide advantages in cases in which it is desirable that the described compound have increased solubility in aqueous compositions and/or increased compatibility with, for example, a binder, if one is used.

Examples of silver-thioamide complexes within Formula I which are stable sources of silver for physical development are silver complexes of the following compounds:

2-thiobarbituric acid,

1,3-diethyl-2-thiobarbituric acid,

2-thiouracil,

imidazolidine-2-thione,

1,3-bis(4-carboxyphenyl)-1,3-dimethylthiourea,

1,3-bis(2-carboxyethyl)-benzimidazole-2-thione, and

4-carboxybenzyl dimethyl dithiocarbamate:

5-carboxy-2-phenyl-4-thiopyrimidine:

5-carbethoxy-1-methyl-2-phenyl-4-thiopyrimidine:

5-methyloxazolidine-2-thione:

1-(3,5-dicarboxyphenyl)-5-mercaptotetrazole

A stable source of metal for physical development which is a stable metal-organic complex of a metal suitable for physical development with a thiazoline-thione or a thiazolidine thione is represented by the structure:

wherein R.sub.6 represents atoms completing a heterocyclic ring, such as

or

, wherein R.sub.8 and R.sub.9 are the same or different, and each is hydrogen, alkyl; especially alkyl containing one to five carbon atoms, such as methyl, ethyl, propyl, butyl and pentyl; aryl, as described; carboxyl; hydroxyl; sulfonic acid; and mercapto; R.sub.7 is hydrogen, alkyl, as described, typically alkyl containing one to five carbon atoms, aryl, especially containing six to 20 carbon atoms, carboxyl or sulfonic acid, as described. These are especially suitable sources of silver for physical development according to the invention.

Examples of suitable silver thiazoline thione complexes which are stable sources of silver for physical development are stable silver complexes of the following compounds:

3-carboxymethyl-4-methyl-thiazoline-2-thione, 3-(2-carboxyethyl)-4-methyl-thiazoline-2-thione,

3-(3-carboxypropyl)-4-methyl-thiazoline-2-thione,

3-(4-carboxybutyl)-4-methyl-thiazoline-2-thione,

3-(5-carboxypentyl)-4-methyl-thiazoline-2-thione,

3-carboxymethyl-4-methyl-5-carboxy-thiazoline-2-thione,

3-(2-carboxyethyl)-4-methyl-5-carboxy-thiazoline-2-thione,

3-(3-carboxypropyl)-4-methyl-5-carboxy-thiazoline-2-thione,

3-carboxymethyl-4-methyl-5-carbethoxy-thiazoline-2-thione,

3-(2-carboxyethyl)-4-methyl-5-carbethoxy-thiazoline-2-thione,

3-(3-carboxypropyl)-4-methyl-5-carbethoxy-thiazoline-2-thione,

3-carboxymethyl-4-carboxymethyl-thiazoline-2-thione,

3-(3-carboxypropyl)-4-carboxymethyl-thiazoline-2-thione,

3-carboxymethyl-4-methyl-5-acetyl-thiazoline-2-thione,

3-(2-carboxyethyl)-4-methyl-5-acetyl-thiazoline-2-thione,

3-sulfoethyl-4-methyl-thiazoline-2-thione,

3-(m-carboxyphenyl)-4-methyl-thiazoline-2-thione,

3-(1-carboxyethyl)-4-carboxy-thiazoline-2-thione,

3-(1-carboxyethyl)-4-carbethoxy-thiazoline-2-thione,

3-(1-carboxyethyl)-4-(carbethoxymethyl)-thiazoline-2-thione,

3-(2-carboxyethyl)-4-(carbethoxymethyl)-thiazoline-2-thione,

3-(2-carboxyethyl)-4-(n-butylsulfonymethyl)-thia-zoline-2-thione,

3-(1,2-dicarboxyethyl)-4-methyl-thiazoline-2-thione, or

4-carboxy-thiazoline-2-thione.

Examples of suitable silver-thiazolidine thione complexes which are stable sources of silver for physical development according to the invention are silver complexes of thiazolidine thione compounds corresponding to the described thiazoline thione compounds. For instance, suitable silver-thiazolidine thione complexes include silver complexes of:

3-carboxymethyl-thiazolidine-2-thione, and

3-carboxyethyl-thiazolidine-2-thione.

A stable source of metal for physical development which is a stable metal-organic complex of a metal suitable for physical development with a thiopyrimidine is represented by the formula:

wherein M is as described; R.sub.10 and R" are individually hydrogen, alkyl or aryl as described, especially phenyl; R.sub.11 is hydrogen, carboxy, alkyl or aryl, as described.

Examples of suitable silver-thiopyrimidine complexes which are stable sources of silver for physical development are stable silver complexes of:

5-carboxy-2-phenyl-4-thiopyrimidine, and

5-carbethoxy-1-methyl-2-phenyl-thiopyrimidine.

A stable source of metal for physical development which is a stable metal-organic complex of a metal suitable for physical development with an oxazolidine-2-thione is represented by the formula:

wherein M, R.sub.5, R.sub.6 and R.sub.7 are as described.

Examples of suitable silver-oxazolidine-2-thione complexes which are stable sources of silver for physical development are:

5-methyloxazolidine-2-thione,

5-carbethoxyoxazolidine-2-thione.

A stable source of metal for physical development which is a stable metal-organic complex of a metal suitable for physical development with a dithiocarbamate is represented by the formula:

wherein M, R.sub.1 and R.sub.2 are as described; and R.sub.12 is alkyl, aryl, as described, or carboxyaryl, or carboxyalkyl, e.g., containing six to 20 carbon atoms, such as carboxybenzyl, carboxyxylyl or carboxyphenyl.

Examples of suitable silver-dithiocarbamate complexes which are stable sources of silver for physical development are stable silver complexes of:

4-carboxybenzyl-dimethyl dithiocarbamate

4-carboxyphenyl-dimethyldithiocarbamate.

A further stable source of metal for physical development is a stable metal-organic complex of a metal suitable for physical development with a thiourea derivative represented by the formula:

wherein M, R.sub.1, R.sub.2, R.sub.4 and R.sub.5 are as described; and R.sub.2 and R.sub.5 can, but need not, be joined to form a heterocyclic ring, represented by the broken line in Structure VI. R.sub.2 and R.sub.5 when joined to form a heterocyclic ring can be, for example,

or

wherein R.sub.1 and R.sub.2 are as described.

Examples of suitable stable sources of silver for physical development are complexes of silver with:

2-thiouracil,

thiobarbituric acid,

imidazolidine-2-thione,

1,3-diethyl-2-thiobarbituric acid,

1,3-bis(2-carboxyphenyl)-1,3-dimethylthiourea.

A stable source of metal for physical development which is a stable metal-organic complex of a metal suitable for physical development with a guanyl-containing compound is represented by the formula:

wherein M, R.sub.1, R.sub.2 and R.sub.3 are as described; R is hydrogen, alkyl or alkylene as described; and any two of the described R groups can be, but need not be, joined to form a heterocyclic ring.

An example of a stable metal-organic complex of a metal suitable for physical development within structure VII is a stable metal-organic complex of a metal suitable for physical development with a pseudothiohydantoin represented by the formula:

wherein M is as described, especially silver.

A further source of metal for physical development is a stable metal-organic complex of a metal suitable for physical development with an imidazolidine, especially a 2-thioimidazolidine represented by the formula:

wherein M, R.sub.1, and R.sub.2 are as described; R' is hydrogen or atoms completing a hydrocarbon ring, e.g., alkylene containing four to eight carbon atoms completing a benzene or naphthylene ring, and their corresponding tautomers.

Examples of suitable stable silver-imidazolidine complexes as stable sources of silver for physical development are complexes of silver with:

imidazolidine-2-thione, or

1,3-bis(2-carboxyethyl)-benzimidazole-2-thione.

A source of metal for physical development is a stable metal-organic complex of a metal suitable for physical development with an imidazoline, especially a 2-thioimidazoline represented by the formula:

wherein M, R.sub.1, R.sub.2 and R' are as described, and their corresponding tautomers.

Examples of suitable stable silver-imidazoline complexes as stable sources of silver for physical development are complexes of silver with:

2(2-carboxyethylthio)-.DELTA..sup.2 -imidazoline

2(2-carboxypropylthio)-.DELTA..sup.2 -imidazoline.

A further source of metal for physical development is a stable metal-organic complex of a metal suitable for physical development with an isothiourea derivative represented by the formula:

wherein R.sub.1 and M are as described, with the exception that R.sub.1 is not hydrogen, R.sub.1 typically being carboxyalkyl or sulfoalkyl. This formula does not include thiourea.

Examples of suitable stable silver-isothiourea derivative complexes as stable sources of silver for physical development are complexes of silver with:

S-(carboxymethyl)isothiourea

S-(2-carboxyethyl)isothiourea

S-(3-carboxypropyl)isothiourea

S-(2-carboxyisopropyl)isothiourea

S-(3-sulfopropyl)isothiourea.

A stable source of metal for physical development is a stable metal-organic complex of a metal suitable for physical development with a mercapto acid, especially a mercapto carboxylic acid represented by the formula:

[HS--R"--COOH] M (XII)

wherein M is as described and R" is alkylene, such as alkylene containing one to 20 carbon atoms, typically alkylene containing one to five carbon atoms, such as methylene, ethylene, propylene, butylene, pentylene, decylene and eicosylene. R" can contain substituent groups which do not adversely affect developing action of the described compounds such as alkyl, e.g., alkyl containing one to 20 carbon atoms, typically alkyl containing one to five carbon atoms as described, carboxy, sulfonic acid, mercapto and amino.

Examples of stable silver mercapto acid complexes which are stable sources of silver for physical development according to the invention are silver complexes of:

mercaptoacetic acid,

mercaptopropionic acid,

mercaptoisobutyric acid,

mercaptosuccinic acid,

alpha-mercaptoadipic acid, and

L-cysteine.

A stable source of metal for physical development is a stable metal-organic complex of a metal suitable for physical development with a mercaptoacetyl amide represented by the formula:

wherein M and R" are as described; R.sub.13 and R.sub.14 are the same or different and each selected from hydrogen; lower alkyl, as described; mercapto; carboxyl; sulfonic acid; hydroxyl and phenyl; at least one of R.sub.13 and R.sub.14 being phenyl. The phenyl group can contain various substituent groups which do not adversely affect the stability and availability of metal for physical development, such as carboxyl, hydroxyl, sulfonic acid, and the like.

Examples of silver-mercaptoacetanilide complexes which are stable sources of silver for physical development include silver complexes of:

mercaptoacetanilide,

mercaptomethylacetanilide, and

mercapto aceto-p-toluidide.

A metal-alkyne complex which is a stable source of metal for physical development according to the invention is represented by the formula:

wherein M is a metal suitable for physical development, as described; R.sub.15 is hydrogen, aryl, as described, alkyl, as described, or alkylene, also as described, forming a ring with R.sub.16, as represented by the broken lines in Structure XIV; R.sub.16 is hydrogen, aryl, alkyl, as described, or alkylene, also as described, forming a ring with R.sub.15 ; R.sub.15 and R.sub.16 together may represent a keto oxygen; R.sub.17 is --O--R.sub.18, --S--R.sub.19,

or an alkylene oxide polymer adduct represented by the formula:

--O(CH.sub.2 CH.sub.2 O).sub.n H

wherein n is an integer, such as an integer from 1 to about 100 or more; R.sub.18, R.sub.19, R.sub.20 and R.sub.21 are the same or different and each selected from hydrogen, acyl or alkyl, as described, typically alkyl containing one to five carbon atoms.

Examples of silver-alkyne complexes suitable according to the invention are silver complexes of:

3-methyl-1-butyn-3-ol

ethylene oxide adduct of 3-methyl-1-butyn-3-ol

3-methyl-1-pentyn-3-ol

ethylene oxide adduct of 3-methyl-1-pentyn-3-ol

1-hexyn-3-ol

1-ethynylcyclopentanol

1-ethynylcyclohexanol

ethylene oxide adduct of 1-ethynyl-cyclohexanol

2-propynyl cyclohexylcarboxylate

4-t-butyl-1-ethynylcyclohexanol

3-(diethylamino)-1-butyne

methyl propiolate

3,5-dimethyl-1-hexyn-3-01

4-(1-hydroxy-2-propynyl)cyclohexene

3-cyclopropyl-1-butyne-3-ol

3-phenyl-1-propyn-3-ol

3-(p-chlorophenyl)-1-butyn-3-ol

ethylene oxide adduct of 3-methyl-1-nonyn-3-ol

A metal-hydroxyalkyl carboxylic acid complex or metal-hydroxy heterocyclic carboxylic acid complex which is a stable source of metal for physical development according to the invention is represented by the formula:

[HO--W--COOH] M (XV)

wherein M is as described and W is alkylene, as described, or a heterocyclic group, typically a five- or six-membered heterocyclic ring, e.g., a triazaindene or a tetraazaindene ring system. The described alkylene and heterocyclic groups can contain various substituent groups, such as alkyl or aryl as described, carboxyl, hydroxyl, sulfonic acid, and the like.

Examples of suitable silver-hydroxy alkyl carboxylic acid complexes according to the invention are silver complexes of:

benzilic acid

glycolic acid

lactic acid

methyl lactic acid

malic acid

tartaric acid

citric acid

tetrahydroxysuccinic acid

12-hydroxystearic acid

and

3,5-dihydroxybenzoic acid.

An example of suitable silver hydroxy heterocyclic carboxylic acid complexes according to the invention is a silver complex with:

6-carboxy-7-hydroxy-1,3a,4-triazaindene

A stable source of metal for physical development is a stable metal-organic complex of a metal suitable for physical development with a thiaalkyl compound of the formula:

[X--S--Z] M (XVI)

including a dithiaalkyl compound of the formula:

[X--S--S--Z] M (XVII)

and/or an oligothiaalkyl compound of the formula:

[X--S --Y--S --.sub.n Z'] M (XVIII)

wherein X and Z are the same or different and each is heterocyclic, aryl, alkyl or acyl, as described; Z' is Z or hydrogen; n is a number, e.g., 1 to 10 inclusive typically 1 to 5; Y is alkylene, as described; and M is a metal suitable for physical development, as described, especially silver.

Heterocyclic, as described herein, includes any heterocyclic group which does not cause undesirable fog or stain and does not adversely affect desired physical development, for example, heterocyclic groups represented by the formulas: ##SPC1##

Examples of other suitable silver-organic complexes which are stable sources of silver for physical development within the described formulas are silver complexes with the following compounds. Some of these can be classified in one or more of the described formulas.

1-(3,5-dicarboxyphenyl)-5mercaptotetrazole

D-xylose diethyl mercaptal

5,5'-dithiobis (1-phenyltetrazole)

11,14,17,20-tetrakis(hydroxymethyl)-13,16,19-trioxa-4,7,10-trithia-1,2,22-d ocosanetriol

2-hydroxyethylamino oligoethylene sulfide

HOCH.sub.2 CH.sub.2 NH(CH.sub.2 CH.sub.2 S).sub.1 6 H

4-(hydroxymethyl)cyclohexylmethyl-amino oligoethylenesulfide

2-(carboxymethylthio)-5-phenyl-1,3,4-oxadiazole

5,5'-thiodisalicylic acid

4-(1,2-dicarboxyethylthio)-5phenylcatechol

S-(o-carboxyphenyl)thioglycolic acid

4-(methylthio)phenol

phenylthioacetic acid

4-(carboxymethylthio)aniline

3-thiavaleric acid

CH.sub.3 CH.sub.2 SCH.sub.2 COOH

2-(2-furylthio)benzoic acid

(2-furylthio)acetic acid

2(2-furylthio)propionic acid

3-(2-furylthio)propionic acid

(2-furylthio)succinic acid

An especially useful stable source of metal for physical development is a stable metal-organic complex of a metal suitable for physical development with a polymer containing a ligand atom having the property of forming a complex with the described metal.

The described polymer includes any polymer which provides the desired complex, does not cause undesired fog or stain and releases the described metal for physical development. These include homopolymers and copolymers, which include interpolymers of various monomeric and polymeric units. These can contain one or more of the same ligand atom or different ligand atoms.

Any ligand atom is suitable which provides the desired complex. Ligand atoms are described in the book, "Organic Complexing Reagents" by D. D. Perrin, Interscience Publishers, Division of Wiley and Co., 1964, especially the first three chapters.

Suitable polymers containing ligand atoms are described, for example, in the book "Vinyl and Related Polymers" by C. D. Shildknecht, John Wiley and Sons, 1952. Especially suitable polymers are those which provide the advantage of serving as a stable source of silver for physical development as well as serving as a binder to partially or totally replace other binders, such as gelatin, which are used in coatings for photographic elements.

Properties of the desired polymers can vary over wide ranges depending on other components of the photographic element with which they can be used, processing conditions, desired image, and the like, which can be determined by those skilled in the art. For example, average molecular weight and viscosity can vary, but are typically sufficiently high that the desired polymer is slid when in the form of a coating, e.g., about 1,000 to 1,000,000 or more.

A suitable stable metal-organic complex of a metal suitable for physical development with a polymer containing a ligand atom is a metal-organic complex of a metal suitable for physical development, especially silver, with a polymer containing thiaalkylacrylamide units and/or thiaalkylmethacrylamide units, such as represented by the formula: ##SPC2##

wherein M is as described; R.sub.22 is methyl or hydrogen; n is a number especially 1 to about 10; m is 0 to about 10; and x is a number of 2 or more, e.g., usually sufficiently high to provide an average molecular weight of about 1,000 to about 1,000,000.

Another suitable stable metal-organic complex of a metal suitable for physical development with a polymer containing a ligand atom is a metal-organic complex of a metal suitable for physical development, especially silver, with a polymer containing thiaalkylacrylate units and/or thiaalkylmethacrylate units such as represented by the formula: ##SPC3##

wherein M, R.sub.22, n, m and x are as described.

Examples of suitable metal-organic complexes according to the invention wherein the organic moiety is a described polymer include silver complexes with:

a terpolymer of (a) 3-thiapentylacrylate, (b) acrylic acid, and (c) 3-acryloxypropane-1-sulfonic acid sodium salt;

a copolymer of (a) 3-thiapentylmethacrylate and (b) 3-acryloxy-propane-1-sulfonic acid sodium salt;

a terpolymer of (a) N-3-thiabutylacrylamide, (b) acrylamide, and (c) 2-methacryloxyethyl acetoacetate; and/or

a copolymer of (a) S-2-methacryloxyethylisothiuronium methane-sulfonate and (b) 3-acryloxypropane-1-sulfonic acid sodium salt.

These polymers have a wide range of average molecular weight, but usually have an average molecular weight of about 100,000 or more.

The described polymers can be prepared employing methods of polymerization known in the art, e.g., such as methods set out in the described Schildknecht reference.

The invention includes other equivalent suitable sources of silver for physical development such as stable silver-organic complexes which are complexes of silver with:

1,10-phenanthroline

1(4-carboxyphenyl)-3,5-dimethyl-4-phenylpyrazole

Sodium dicyanamide

NaN(CN).sub.2

8-hydroxyquinoline

8-hydroxyquinoline sulfate

saccharin

2,4-thiazolidihedione

Combinations of metal complexes can be employed according to the invention, such as combinations of silver complexes with gold, platinum or palladium complexes, or combinations of different organic complexing moieties, such as combinations of thiazoline thiones with alkynols or different thiazoline thiones with each other.

Metal and M as described herein with regard to metal-organic complexes refer to a metalic ion or the described metals in ionic form, such as a silver ion, mercury ion, platinum ion, gold ion, copper ion, and the like. In the described metal-organic complexes which are stable sources of metal for physical development according to the invention, it is believed the metal is in ionic form.

Whether a metal-organic complex employed according to the invention is suitably stable will depend on several factors, such as the specific organic moiety, the components of the photographic element used, the affinity of the metal used for physical development, especially silver, to the organic moiety, the processing conditions and the like. Suitable stability is also related to keeping characteristics of a photographic element containing a described metal organic complex. Usually, regarding this factor, compared to a control, if a photographic element does not show undesired loss in photographic speed and/or density after certain periods of time, such as after a few days, at about 50.degree. C. and about 50 percent relative humidity, a metal-organic complex in the element is considered as suitably stable.

The elements described employing a silver-dye complex as a radiation-sensitive component, for example, with the described silver complexes as stable sources of silver for physical development can produce good reflection densities and high resolving power, e.g., resolving power over 2,000 line pairs per millimeter and many of the described elements have good stability, e.g., do not lose photographic speed or density after two weeks at about 50.degree. C. and about 50 percent relative humidity.

Whether a metal-organic complex employed according to the invention is suitably stable depends heavily on the affinity for silver ion of the described organic moiety of the metal-organic complex used according to the invention. This can be measured as pAg. A suitable pAg range can vary.

A suitable pAg range in a radiation sensitive element according to the invention is about 2.0 to about 10 and a range of about 3 to about 7 is typically employed. If a pAg above about 10 is employed the risk of inhibition of desired development is great. But, if a pAg below about 2.0 is employed there is a risk of background fog formation. In the case of a photographic element containing a silver-dye complex as a radiation sensitive component, and a described silver-organic complex according to the invention as a stable source of silver for physical development, a concentration of about 0.01 mole to about 0.0001 mole of dye per mole of silver present and a concentration of about 0.2 mole to about 5.0 moles of organic moiety used to form the described silver-organic complexes of the invention per mole of silver in the element is suitable providing the desired pAg as described.

The concentration of described metal complexes suitable according to the invention can vary depending on the desired image, processing conditions, components of the photographic element, the affinity of the organic moiety of the described metal complexes for metal, especially silver, and the like, which can be determined by those skilled in the art. If the described silver complexes are incorporated in a photographic element containing a photographic silver salt, especially a described silver dye complex, a suitable ratio of (a) moles of organic moiety employed to form the desired silver complex as a stable source of silver for physical development to (b) moles of total silver in the photographic element is about 0.2 to about 7, depending upon the affinity of the organic moiety of the silver complex for silver. Especially suitable ratios of (a) moles or organic moiety employed to form the desired silver complex employed as a stable source for physical development to (b) moles of silver in an element containing the described silver complex are set out in the following examples. If the described silver complexes are employed in a processing composition, such as a physical developer composition, e.g., a physical developer solution with which a photographic element is contacted, higher concentrations of silver complex can be desirable, depending on the image desired, processing conditions and other factors described. A concentration of about 0.1 percent by weight to about 15 percent by weight of described metal complex of the total processing composition is usually suitable, but concentrations outside this range can be employed if desired.

While a wide range of ratios of concentration of described organic moiety to concentration of silver in a system according to the invention can be employed, a suitable concentration depends heavily on the affinity for silver ion of the described organic moiety, which can be measured as pAg. Availability of silver ion can be measured using a pAg electrode. A low value indicates high silver ion activity or availability and vice versa.

The suitable concentration of total silver in coatings of photographic elements employing a silver-dye complex as a radiation-sensitive component and a described silver complex as a stable source of silver for physical development can vary over a wide range, but typically about 30 mg. per square foot to about 200 mg. per square foot of silver is suitable. It will be appreciated that this is a significantly higher concentration than employed in a coating containing only a silver-dye complex.

The described silver complexing agents of the invention, especially the described thiazoline-2-thiones and thiazolidine-2-thiones, can provide toning for the developed image.

The various layers of the photographic elements described herein can be hardened with any suitable hardener, including, for example, aldehyde hardeners, aziridine hardeners, hardeners which are derivatives of dioxane, oxypolysaccharides, such as oxystarch, oxy plant gums, and the like. The layers of the photographic element can contain hardeners such as alkali soluble bisulfite-aldehyde addition products which harden hydrophilic colloids such as gelatin at a pH greater than about 7. Such hardeners can conveniently be incorporated into photographic silver halide emulsion layers or other layers of an element particularly gelatin having layers, since such layers are generally coated under acid conditions, i.e., at a pH which is generally less than about 6. Suitable alkali metal bisulfitealdehyde addition products include, for example, sodium formaldehyde bisulfite, glutaraldehyde bis(sodium bisulfite), betamethyl glutaraldehyde bis(sodium bisulfite), maleic dialdehyde bis(sodium bisulfite), and the like.

Various colloids can be used alone or in combination as vehicles or binding agents in the photographic emulsions and elements employed in the practice of this invention. Among such materials are the natural and/or synthetic binding materials generally employed for this purpose including, for example, gelatin, colloidal albumin, water-soluble vinyl polymers as exemplified by mono- and polysaccharides, cellulose derivatives, proteins, water-soluble polyacrylamides, polyvinyl pyrrolidone, and the like. In addition to the hydrophilic colloids, the vehicle or binding agents can contain dispersed polymerized vinyl compounds particularly those which increase the dimensional stability of photographic materials. Suitable synthetic polymers of this type include water-insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates and the like.

A wide range of photographic components can be employed as the described main photographic component used in a photographic element, composition and/or process of the invention. While some of the described stable metal-organic complexes used as a source of metal for physical development do have some photosensitivity they are used according to the invention as a source of metal for physical development and not as a radiation-sensitive component, i.e., a component which upon exposure to radiation forms latent image sites which can be physically developed. A preferred main photographic component is a silver-dye complex as described. If desired, silver halides can be employed in the photographic elements, processes and compositions of the invention, especially as the main photographic component, including any of the photographic silver halides as exemplified by silver bromide, silver iodide, silver chloride, mixed silver halides, such as silver chlorobromide, silver bromoiodide, and the like. The silver halides can be those which form latent images predominantly on the surface of the silver halide grains or those which form latent images inside the silver halide crystals, as exemplified by Davey and Knott, U.S. Pat. No. 2,592,250 issued Apr. 8, 1952, as well as direct positive emulsions, such as those described in Kendall and Hill, U.S. Pat. No. 2,541,472 issued Feb. 13, 1951. Other photographic silver salts can be employed, such as silver salts of sulfur-containing aliphatic carboxylic acids, as described in U.S. Pat. No. 3,330,663 of Weyde et al. issued July 11, 1967.

The photographic layers described herein can be coated on a wide variety of supports. Typical flexible supports include those generally employed for photographic elements, such as cellulose nitrate film, cellulose acetate film, polyvinylacetal film, polystyrene film, polyethylene terephthalate film, and related films or resinous materials as well as glass, paper, metal and the like. Supports such as papers which are partially acetylated or coated with baryta or an olefin polymer, particularly a polymer of an alpha-olefin containing two to 10 carbon atoms as exemplified by polyethylene, polypropylene, ethylene-butene copolymers, and the like, give good results.

The photographic emulsions and elements of this invention can also contain additional addenda, particularly those known to be beneficial in photographic materials of this nature. For example, they can contain stabilizers or antifoggants such as cadmium, lead, mercury, gold, or other noble metal salts, spectral sensitizers, such as the cyanines, merocyanines, complex (trinuclear) cyanines, complex (trinuclear) merocyanines, styryls, hemicyanines, speed-increasing materials, such as polyalkylene glycols, onium salts and thioethers, plasticizers, coating aids such as anionic, nonionic and amphoteric surface active compounds, and the like. The photographic silver halide emulsions disclosed herein can also be chemically sensitized with compounds of the sulfur group, such as sulfur, selenium and tellurium sensitizers, noble metal salts, such as gold, or reduction sensitized with reducing agents or combinations of such materials. The photographic elements can contain fluorescent brighteners such as stilbenes, coumarins, benzothiazoles, benzoxazoles, imidazoles, etc. Suitable fluorescent brighteners are described in McFall et al. U.S. Pat. No. 2,933,390, British Patent 786,235, U.S. Pat. No. 3,025,242 and German Patent 1,150,274.

A wide range of coating methods can be employed for preparing photographic elements according to the invention. In general, any of those methods commonly employed in preparing coatings for photographic elements are suitable.

A silver halide developing agent can be employed in providing physical development according to the invention. A wide range of silver halide developing agents are suitable. These include polyhydroxybenzene developing agents, such as hydroquinone developing agents, e.g., hydroquinone, alkyl substituted hydroquinone, such as t-butyl hydroquinone, methyl hydroquinone, dimethyl hydroquinone, catechol, and pyrogallol, chloro-substituted hydroquinones, such as chlorohydroquinone, alkoxy-substituted hydroquinones, such as methoxy or ethoxy hydroquinone, aminophenol developing agents, such as N-methyl-p-aminophenol and 2,4-diaminophenols, ascorbic acid developing agents, pyrazolidone developing agents, including those described in British Patent 958,678 and British Patent 930,572, acyl derivatives of p-aminophenol, and the like. Such developing agents can be used alone or in combination. It is usually desirable that the developing agent employed be soluble in water. The suitable concentration can vary over wide ranges depending on the desired image, the components of the photographic element, processing conditions, and the like.

The desired silver complexes are suitable in layers of photographic elements used for color photography, such as emulsions containing color-forming couplers or emulsions developed by solutions containing couplers or other color-generating materials; emulsions of the mixed packet type, such as described in U.S. Pat. No. 2,698,794 of Godowsky issued July 9, 1955; or emulsions of the mixed grain type, such as described in U.S. Pat. No. 2,592,243 of Carroll and Hanson.

The described silver complexes as stable sources of silver for physical development can be employed in photographic elements processes and compositions intended for use in diffusion transfer processes which utilize undeveloped silver salts in the nonimage areas of the negative to form a positive by dissolving the undeveloped silver salts or complexes and precipitating them on a receiving layer in close proximity to the original silver salt emulsion layer. Such processes are described, for example, in U.S. Pat. No. 3,020,155 to Yackel et al. issued Feb. 6, 1962, U.S. Pat. Nos. 2,584,029 issued Jan. 29, 1952; 2,698,236 issued Dec. 28, 1954; and 2,543,181 issued Feb. 27, 1951 of E. H. Land and U.S. Pat. No. 2,352,014 of Rott issued June 20, 1944. The invention can also be used in color transfer processes which utilize the diffusion transfer of developer, coupler or dye, from a light-sensitive layer to a second layer, such as described in U.S. Pat. No. 2,559,643 of Land, issued July 10, 1951; U.S. Pat. No. 2,698,798 issued Jan. 4, 1955; U.S. Pat. No. 2,756,142 of Yutzy issued July 14, 1956; U.S. Pat. No. 3,252,915 of Weyerts et al. issued May 31, 1966; and U.S. Pat. No. 3,227,550 of Whitman et al. issued Jan. 4, 1966. The described silver complexes are useful in other elements and processes designed for color photography, such as described in U.S. Pat. No. 3,242,294 of Barr et al. issued Mar. 29, 1966 and U.S. Pat. No. 2,252,718 of Mannes et al. issued Aug. 14, 1961.

The invention can be employed with photographic elements and processes designed for use in lithography, preparation of direct prints, or in colloid transfer processed, as well as in elements designed for processing in monobath processes, such as in monobath processes described in U.S. Pat. No. 2,875,048 of Haist et al. issued Feb. 24, 1959, and web-type processing such as described in U.S. Pat. No. 3,179,517 of Tregillus et al.

Another embodiment of the invention is a photographic process comprising physical development of a latent image in a radiation-sensitive metal salt employing a stable source of metal especially silver, for the described physical development which is a stable metal complex as described herein.

An especially suitable process, however, comprises physically developing a latent image in a photographic element containing (a) a silver-dye complex which has the property of forming active sites for physical development upon exposure to radiation and (b) a stable source of silver for physical development which is a stable metal complex, as described, wherein the metal is silver, with a silver halide developer solution.

A wide range of processing conditions can be employed depending on the desired image, photographic element processed, developer employed and the like. Processing is usually carried out under ambient conditions of temperature and pressure, e.g., a temperature of about 20.degree. C. to about 30.degree. C., but higher temperatures can be employed if desired, such as temperatures above about 50.degree. C., e.g., about 50.degree. to about 150.degree. C.

The time required for processing can vary widely, such as from about 1 second to several minutes or more depending on processing conditions and desired image. Employing an element containing a described silver-dye complex and a described stable source of silver for physical development, a good image can be produced in about 2 to about 60 seconds when a silver halide developer solution is employed for processing.

Development activators which can be used according to the invention include any of those which provide the desired activation of the described developing agents. These include alkaline activators such as inorganic alkalis, for example, sodium hydroxide, potassium hydroxide and lithium hydroxide, alkali metal carbonates, such as sodium carbonate and potassium carbonate, and organic alkaline development activators such as quaternary ammonium bases and salts and similar alkaline materials and/or alkali releasing materials, and the like.

Processing compositions, such as developer solutions and/or stabilizer solutions and/or activator solutions, can be applied to or otherwise contacted with the described photographic elements in any suitable manner, including for instance, dipping, spraying and/or suitable surface applications, such as with rollers or other mechanical means.

A useful process according to the invention of effecting development of a photographic element containing a silver-dye complex, as described, and a silver-organic complex, as described, which is a stable source of silver for physical development comprises contacting the photographic element with a silver halide developing agent in the presence of a development activator, such as contacting the photographic element with an aqueous alkaline developer solution. This silver halide developer can be a physical developer if desired, e.g., one containing a source of silver for physical development, such as a water-soluble silver salt, e.g., silver nitrate, and/or one of the described silver complexes.

A further embodiment of the invention is a photographic composition comprising (a) a stable source of metal for physical development which is a stable metal complex, as described herein, and (b) a silver-dye complex which has the property of forming active sites for physical development upon exposure to radiation. This photographic composition can be a photographic emulsion.

Another embodiment of the invention is a physical developer composition comprising:

A. a silver halide developing agent and/or other suitable reducing agent, and

B. a stable source of metal for physical development which is a stable metal complex as described. This physical developer is typically an alkaline solution, such as an alkaline solution containing a polar solvent including, for example, water, ethylene glycol, alcohol, and the like.

It is often desirable to include a suitable hardener, as described herein, in the physical developer. A wide range of concentrations can be employed, depending on the element processed, processing conditions, components of the physical developer, and the like. A concentration of about 0.1 to about 1.5 percent by weight of hardener of the total physical developer composition is usually sufficient.

One or more components of the described physical developer can be stored in separate containers, such as in separate packets or bottles as part of a kit before use. At the time of or shortly before use, the component or components can be mixed together and/or diluted with a suitable solvent, such as water, to the desired concentration.

It can be advantageous in some cases to have an antifoggant present in a processing composition according to the invention and/or in the photographic element processed. Suitable antifoggants include organic antifoggants, such as benzotriazole, benzimidazole, 2-mercaptobenzimidazole, and mercaptoazole antifoggants. An inorganic antifoggant, such as potassium bromide, potassium iodide and/or sodium bromide can be employed if desired. One of the advantages of the invention is that some of the organic complexing moieties can provide toning of the developed image. Some of the organic complexing moieties are also antifoggants.

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

EXAMPLE 1

A photographic element is prepared in Example 1 employing a coating of the following mixture on a film support:

Concentration Component in milliliters __________________________________________________________________________ a. 0.002 molar aqueous solution of 1-carboxymethyl-5-[(3-ethyl-2- benzoxazolinylidene)-ethylidene]- 3-phenyl-2-thiohydantoin (dye) 0.5 b. 0.2 molar aqueous solution of silver-p-toluene sulfonate 1.1 c. aqueous solution containing 10% by weight photographic gelatin 5.5 d. aqueous solution containing 15% by weight saponin 0.25 e. aqueous solution containing 10% by weight formaldehyde 0.06 __________________________________________________________________________

One milliliter of solution of the organic moiety set out in following Table I on column A is added to the resulting mixture before coating and the volume brought to about 12 ml. with water. This solution contains a concentration of described organic moiety sufficient to provide a preferred ratio of moles of organic moiety to moles of silver designated in column B thus forming the desired silver complex in situ. A plus sign (+) in column B indicates the useful range exceeds the designated value. The mixture is coated on a film support producing a coating containing 60 mg. of silver per square foot. After drying the element is exposed sensitometrically and the resulting latent image developed by immersing in the following solution:

Sodium sulfite 90.0 g. Hydroquinone 45.0 g. Sodium hydroxide 37.5 g. Potassium bromide 30.0 g. Water to 1 l.

and fixed by immersing for 2 minutes in the following solution:

Sodium thiosulfate 240.0 g. Sodium sulfite 15.0 g. Acetic acid (28%) 48.0 cc. Boric acid 7.5 g. Potassium alum 15.0 g. Water 1 l.

A high-resolution neutral image having high covering power (covering power=density/silver coverage in grams per square foot) and good reflection density is produced in each instance. --------------------------------------------------------------------------- TABLE I

Column A: Column B: moiety complexed ratio of moles with silver as of organic stable source of moiety to total silver for physical moles of silver Example development in coating __________________________________________________________________________ 1 Mercaptoacetic acid 0.35-0.50 2 Mercaptopropionic acid 0.25-0.35 3 Mercaptoisobutyric acid 0.35-0.50 4 Mercaptosuccinic acid 0.3-0.65 5 alpha-Mercaptoadipic acid 0.5-0.7 6 L-cysteine 0.2-0.5 7 Mercaptoacetanilide 0.6-0.9 8 Thiobarbituric acid 0.3-0.4 9 1,3-diethyl-2-thiobarbituric acid 1.5-3.0 10 2-Thiouracil 0.5-0.7 11 Imidazolidine-2-thione 0.6-0.9 12 1,3-bis(4-carboxyphenyl)- 1,3-dimethylthiourea 0.8-1.2 13 1,3-bis(2-carboxyethyl)- benzimidazole-2-thione 1.2-1.5 14 1-(3,5-dicarboxyphenyl)- 5-mercaptotetrazole 0.55-0.8 15 D-xylose diethyl mercaptal 1.2-2.0+ 16 5,5'-dithiobis(1-phenyltetra- zole) 0.6 17 4-carboxybenzyl dimethyl- dithio-carbamate 1.36 18 11,14,17,20-tetrakis(hydroxymethyl)- 13,16,19-trioxa-4,7,10-trithia- 1,2,22-docosanetriol 1.8-2.0+ 19 2-hydroxyethylamino-oligoethylene- sulfide 0.6-0.8 20 4-(hydroxymethyl)cyclohexylmethyl- aminooligoethylenesulfide 0.6-0.9 21 5-carboxy-2-phenyl-4-thiopyridine 4-0.7 22 5-carbethoxy-1-methyl-2-phenyl-4- thiopyrimidine 1.0-1.3 23 5-methyloxazolidine-2-thione 0.6-0.7 24 2-(carboxymethylthio)-5-phenyl- 1,3,4-oxadiazole 1.0-3.0+ 25 4-(1,2-dicarboxyethylthio)- 5-phenylcatechol 1.2-2.7 26 S-(o-carboxyphenyl)thioglycolic acid 1.5-3.0+ 27 4-(methylthio)phenol 4.0+ 28 Phenylthioacetic acid 1.0-3.0+ 29 4-(carboxymethylthio)aniline 1.0-3.0 30 3-thiavaleric acid 1.2-2.0+ 31 S-(carboxymethyl)isothiourea 0.8-2.1 32 S-(2-carboxymethyl)isothiourea 0.2-2.0 33 S-(3-carboxypropyl)isothiourea 0.4-1.2 34 S-(2-carboxyisopropyl)isothiourea 0.8-2.0+ 35 S-(3-sulfopropyl)isothiourea 1.4-2.0 36 2(2-carboxyethylthio)-.DELTA..sup.2 - imidazoline 0.8-2.0 37 2-(2-furylthio)benzoic acid 1.2-3.0+ 38 (2-furylthio)acetic acid 1.5-3.0+ 39 2(2-furylthio)propionic acid 1.4-3.0+ 40 3-(2-furylthio)propionic acid 1.2-3.0+ 41 (2-furylthio)succinic acid 0.3-3.0+ 42 3-thiaglutaric acid 0.4-2.0+ 43 3-thiaadipic acid 0.6-3.0+ 44 4-thiapimelic acid 0.2-1.8 45 4-carboxy-3-thiadipic acid 0.5-2.0+ 46 2,2,6,6-tetramethyl-4-thiapimelic acid 1.5-3.0+ 47 5,5-dicarbethoxy-2,2-dimethyl- 3-thiavaleric acid 0.5-2.0+ 48 4-oxo-3-thiavaleric acid 0.6-2.0+ 49 3,3'-dithiodipropionic acid 0.2-2.0+ 50 5-thioctic acid 1.0-4.0 51 2,2'-dithiodibenzoic acid 0.3-1.5+ 52 3,5-dithiapimelic acid 1.5-2.0+ 53 4-methyl-3,5-dithiapimelic acid 0.2-2.0+ 54 (Cyclohexylidenedithio)diacetic acid 0.2-2.0+ 55 Acetylenetetrathiotetraacetic acid 0.3-3.0+ 56 3,6-dithiasuberic acid 0.2-2.0+ 57 4,5-dimethyl-3,6-dithiasuberic acid 0.2-2.0+ 58 2,7-dimethyl-3,6-dithiasuberic acid 0.8-2.0+ 59 2,8-dimethyl-3,7-dithiasebacic acid 0.8-2.0+ 60 3,9-dithiahendecane-1,11-dioic acid 1.4-2.0+ 61 Copoly(N-3-thiabutylacrylamide) (3-acryloyloxypropane-1-sulfonic acid sodium salt) 1:1 or 1:3 mole ratio 1.0-3.0+ 62 3-methyl-1-butyn-3-o1 1.0-1.4+ 63 1,8 mole ethylene oxide adduct of 3-methyl-1-butyn-3-o1 1.0-3.0+ 64 5 mole ethylene oxide adduct of 3-methyl-1-butyn-3-o1 0.6-3.0+ 65 3-methyl-1-pentyn-3-o1 0.5-1.4+ 66 2.2 mole ethylene oxide adduct of 3-methyl-1-pentyn-3-o1 1.2-3.0+ 67 1-hexyn-3-o1 0.7-1.4+ 68 1-ethynylcyclopentanol 0.3-3.0+ 69 1-ethynylcyclohexanol 0.6-2.2+ 70 2.2 mole ethylene oxide adduct of 1-ethylnylcyclohexanol 1.2-3.0+ 71 2-propynyl cyclohexylcarboxylate 0.8-1.4+ 72 4-t-butyl-1-ethynylcyclohexanol 0.5-3.0+ 73 3-(diethylamino)-1-butyne 0.3-3.0+ 74 Methyl propiolate 2.7-3.0+ 75 3,5-dimethyl-1-hexyn-3-o1 0.6-1.4+ 76 4-(1-hydroxy-2-propynyl) cyclohexene 0.7-1.4+ 77 3-cyclopropyl-1-butyn-3-o1 1.8-3.0+ 78 3-phenyl-1-propyn3-o1 1.4-3.0+ 79 3-(p-chlorophenyl)-1-butyn-3-o1 0.3-3.0+ 80 3-methyl-1-nonyn-3-o1, 10 mole ethylene oxide adduct 0.9-3.0+ 81 1,10-phenanthroline 1.5 82 1-(4-carboxyphenyl)-3,5-dimethyl 4-phenylpyrazole 0.6 83 Sodium dicyanamide (NaN(CN).sub.2) 1.0-6.0+ 84 6-carboxy-7-hydroxy-1,3a,4- triazaindene 1.0-2.0 85 8-hydroxyquinoline 1.2-2.0+ 86 8-hydroxyquinoline sulfate 0.8-2.0+ 87 Saccharin 2.4-4.0+ 88 Pseudothiohydantoin 0.8-2.0+ 89 2,4-thiazolidinedione 0.6-3.0+ 90 5-sulfobenzotriazole up to 1.0 91 (m-phenylenedioxy)diacetic acid 1.5-4.0+ 92 Glycolic acid 3.0+ 93 Lactic acid 3.0+ 94 Methyllactic acid 2.7-3.0+ 95 Malic acid 0.3-3.0+ 96 Tartaric acid 0.6-3.0+ 97 Citric acid 0.3-3.0+ 98 Tetrahydroxysuccinic acid 0.6-1.8 99 12-hydroxystearic acid 1.5-3.0+ 100 Oxalic acid 0.7-4.0+ __________________________________________________________________________

EXAMPLE 101

The procedure set out in Example 1 is repeated with a silver-organic complex using organic moieties within the scope of the following formula in place of the designated organic moiety of Examples 1-100:

wherein R.sub.30, R.sub.31 and R.sub.32 are set out respectively in column A, B and C of Table II. The concentration of described 4-thiazoline-2-thione is sufficient to provide a preferred ratio of moles of organic moiety to total moles of silver in the element. This is designated in column D of Table II. The resulting photographic element is exposed sensitometrically and the resulting latent image developed and fixed as set out in Example 1. A high-resolution neutral image having covering power and good reflection density is produced in each instance. ##SPC4##

EXAMPLE 126

This illustrates a diffusion transfer process according to the invention.

A photographic element is prepared by coating the following mixture on a film support:

Component Milliliters __________________________________________________________________________ a. aqueous solution containing 15% by weight of saponin 1.9 b. 0.016 molar aqueous solution of 1-carboxymethyl-5-[(3-ethyl-2- benzoxazolinylidene)-ethylidene]- 3-phenyl-2-thiohydantoin (dye) 1.5 c. 0.2 molar aqueous solution of silver-p-toluene sulfonate 28.0 d. aqueous solution containing 15% by weight of photographic gelatin 95.0 e. 0.25 molar solution of 5-carboxy-3- (carboxymethyl)-4-methyl-4-thiazoline- 2-thione (forms silver complex in situ) in ethanol 28.0 f. 7 N Sulfuric acid 1.0 g. 0.16 molar aqueous ethanol solution of mucochloric acid 7.5 h. 0.1 N aqueous sodium hydroxide solution 4.5 __________________________________________________________________________

This is coated on a film support at the rate of 60 mg. per square foot of silver. After drying, it is exposed sensitometrically. A paper receiver sheet containing colloidal silver development nuclei is soaked for 2 minutes in a monobath having the following composition:

2-methylaminoethanol (17.2% SO.sub.2 adduct) 45 ml. Hydroquinone 11 g. Sodium thiosulfate pentahydrate 16 g. Sodium hydroxide 15 g. 4-methyl-1-phenyl-3-pyrazolidone 4.5 g.

The paper receiver sheet is then laminated to the exposed coating for 30 seconds. A positive image is formed on the receiver sheet and has a clean background. The positive image has a maximum density of 1.2.

EXAMPLE 127

This illustrates color processing according to the invention.

A photographic element is prepared as set out in Example 101. After drying, the resulting coating is exposed sensitometrically. It is then immersed in a color developer containing a cyan coupler as described in U.S. Pat. No. 2,252,718 of Mannes et al. It is then immersed successively in a stop-fix bath, a bleach bath, and a fix bath as described in this U.S. patent to provide the desired colored image. The resulting cyan image has good sharpness of detail over a range of densities.

Other color couplers which are suitable are set out in U.S. Pat. No. 3,113,864 of Yager et al.

EXAMPLE 128

Good results are obtained when an element and process is employed according to U.S. Pat. No. 2,113,329 of Mannes issued Apr. 5, 1938 employing a silver complex of 5-carbethoxy-3-carboxymethyl-4-methyl-4-thiazolidone-2-thione as a stable source of silver for physical development, as set out in Example 1, in the initial development step of this color process.

EXAMPLE 129

The procedure set out in the immediate preceding example is repeated employing 1-ethynylcyclopentanol in place of the described thiazoline-2-thione compound.

A good image is obtained.

EXAMPLE 130

A good color image is obtained employing an element and process described in U.S. Pat. No. 2,304,940 of Mannes et al. using a photographic element containing incorporated described magenta couplers and cyan couplers with a green sensitive silver dye complex as described in French Patent 1,453,635 of Gilman, Goffe and Jones issued Aug. 16, 1966. A silver complex with 5-carbethoxy-3-carboxymethyl-4-methyl-4-thiazolidine-2-thione as a stable source of silver for physical development is employed as set out in Example 1, in this element designed for color processing.

EXAMPLE 131

The procedure set out in the immediate preceding example is repeated employing 1-ethynylcyclopentanol in place of the described thiazoline-2-thione compound.

A good image is obtained.

EXAMPLE 132

A good color image is also obtained employing an element and process described in U.S. Pat. No. 2,304,940 of Mannes et al. using a blue sensitive silver-dye complex and a yellow coupler in a first layer, a green sensitive silver-dye complex and a magenta coupler in a second layer and a red sensitive silver-dye complex and a cyan coupler in a third layer. The red sensitive silver-dye complex, green sensitive silver-dye complex and blue sensitive silver-dye complex are as described in French Patent 1,453,635 of Gilman, Goffe and Jones issued Aug. 16, 1966, and the described couplers are set out in Mees, "The Theory of the Photographic Process," Third Edition, (1966), page 394. A complex of silver with 5-carbethoxy-3-carboxymethyl-4-methyl-4-thiazolidine-2-thione is employed in each layer of the photographic element, as set out in Example 1, as a stable source of silver for physical development in the initial development step of the process.

The results of the preceding examples indicate that coatings are obtained designed for color processing which are less turbid than photographic silver halide coatings, provide high resolution and sharpness, provide advantageous spectral sensitivity, eliminate the necessity of a yellow filter layer to account for inherent blue sensitivity of silver halide and eliminate many complicated ripening holding, noodling and/or washing steps necessary in the preparation of photographic silver halide coatings.

EXAMPLE 133

This is a comparative example illustrating certain advantages according to the invention.

Three photographic elements are prepared as in Example 1. Each one of the three, however, contains a different source of silver for physical development as follows:

A. silver-5-carbethoxy-3-carboxymethyl-4-methyl-4-thiazolidine-2-thione

B. silver thiosulfate (prior art)

C. silver-4,5-(2,3,D-fructopyrano)-2-oxazolidine-thione (prior art)

The coatings are exposed sensitometrically and developed as set out in Example 1. The following results are obtained:

Photographic Coating Dmax Dmin Speed Tone __________________________________________________________________________ A 2.1 0.20 1.0 Neutral Black B brown fog, no image C 1.4 0.25 0.4--0.5 Blue-gray __________________________________________________________________________

The results demonstrate that a combination of increased maximum density, better neutral black tone, and reduction of fog or stain, in addition to increased photographic speed can be obtained according to the invention as compared to use of related known sources of silver for physical development.

The elements, processes and compositions of the invention are useful in physical development of a latent image in an exposed radiation-sensitive titanium compound, such as titanium dioxide or a titanium dioxide dye complex, such as described in French Patent 1,437,765. Although the exact mechanism of reaction which takes place is not fully understood, it is believed that when a dye-sensitized titanium dioxide is employed with a described silver-dye complex in combination with a described silver-organic complex of the invention as a stable source of silver for physical development a bifunctional radiation-sensitive coating is provided. That is, two different types of radiation-sensitive compounds are provided which can be processed selectively to provide two different types of images. For example, employing a mixture of (a) silver-dye complex, as described herein, (b) a dye-sensitized titanium dioxide compound, as described in French Patent 1,437,765 and (c) a silver-organic complex, as described herein, as a stable source of silver for physical development, a radiation-sensitive element can be exposed with a high-intensity exposure. The resulting image is developed as described in Example 1 to provide only an image from the silver-dye complex. However, an exposure of about 10 to about 50 times less than the intense exposure followed by physical development after immersing in a solution containing a water-soluble silver salt, provides an image resulting from the titanium dioxide. This provides the advantage that a permanent silver image, which can be developed or not as desired, can be produced with the option of adding information later by means of the latent image in the titanium dioxide. Both the titanium dioxide and silver-dye complex, as described, provide sites for physical development using the stable sources of metal for physical development according to the invention.

EXAMPLE 134

This illustrates the invention employing titanium dioxide, which is dye sensitized as a radiation-sensitive component.

A photographic element is prepared by mixing and coating the following components at 40.degree. C. under red safe-light conditions:

Component Concentration __________________________________________________________________________ a. 0.2 molar aqueous methanol solution of 5-carbethoxy-3-carboxymethyl-4- methyl-4-thiazoline-2-thione 2 ml. b. 10% aqueous solution of photographic gelatin 10 ml. c. 0.2 N aqueous solution of silver-p- toluene sulfonic acid 2 ml. d. suspension formed from: 6 ml. i. 6 g. titanium dioxide ii. 30 ml. water iii. 12 mg. of a ligand dye, 1,2-dihydroxy- anthraquinone (alizarin) in 1 ml. dimethyl formamide, iv. 21 ml. of 10% aqueous solution of photographic grade gelatin e. 15% aqueous solution of saponin 0.4 ml. f. 10% aqueous solution of formaldehyde 0.4 ml. __________________________________________________________________________

This composition is coated on a paper support at a rate of 0.009 inch wet thickness. The coating is dried and exposed sensitometrically using a 100-watt tungsten light source. The resulting coating is developed as set out in Example 1. Only an image characteristic of the exposed silver-dye complex is visible. After 80 minutes storage in the dark, the element is exposed sensitometrically a second time, for 10 seconds, on a portion of the element which contains no developed image. The element is then immersed in a 1 percent aqueous silver nitrate solution for 10 seconds followed by rinsing in water for 10 seconds and developing as set out in Example 1. A second image, of lower density than the silver-dye image and characteristic of a titanium dioxide sensitized with dye image, is developed.

The metal-organic complexes, described herein, can be employed in a physical development process as set out in U.S. Pat. No. 2,735,773 of Dippel and Houtman issued Feb. 21, 1956 or U.S. Pat. No. 2,764,484 of Jonge et al. issued Sept. 25, 1956. For example, according to the invention a radiation-sensitive material, such as a photographic element containing a silver-dye complex, subsequent to exposure is contacted in a suitable manner with mercurous ions, for example, in 0.01 N mercurous nitrate or a mercurous salt of one of the described compounds of the invention, and then is contacted in a suitable manner with a physical developer containing a metal-organic complex according to the invention, such as a silver-thiazoline-2-thione or silverthiazolidine-2-thione complex.

The described 2-furyl thioethers, especially 2-furyl thioethers which contain a carboxyalkylthio or carboxyarylthio group in the 2 position of a furan ring, can be prepared by a one step method by reacting (a) an aliphatic or aromatic mono- or dithiol with (b) a 2,5-diloweracyloxy-2, 5-dihydrofuran; 2,5-dihydro-2,5-diloweralkoxyfuran; 2,5-dihydro-2,5-diloweralkoxy-2-methylfuran; or fumaric dialdehyde. This preparation is described in copending application Ser. No. 764,331 now U.S. Pat. No. 3,591,609, of R. A. Silverman filed concurrently herewith. For example (2-furylthio)-propionic acid can be prepared by refluxing thiopropionic acid with 2,5-dihydro-2,5-dimethoxyfuran in about stoichiometric concentrations in a suitable solvent such as acetonitrile or acetic acid.

The exact bonding in the reaction product of the described organic moieties and metal suitable for physical development as described, is not fully understood. These reaction products, such as the reaction product of a thiazoline-2-thione compound with a water-soluble silver salt, such as silver nitrate, are designated as metal-organic complexes. These can include bonding which is covalent, ionic, or some other type. For example, a described metal-organic complex can be a so-called metal-organic salt, e.g., a silver salt, containing bonding which is characteristic of metal salts.

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

Claims

I claim:

1. A photographic element comprising a support, a radiation-sensitive silver-dye complex which has the property of forming active sites for physical development upon exposure to radiation and a stable source of metal for physical development which is a stable metal-organic complex of a metal suitable for physical development with a compound which is:

a thiazoline thione, a thiazolidine thione, a thiopyrimidine,

a dithiocarbamate represented by the formula:

a thiourea derivative represented by the formula:

a pseudothiohydantoin represented by the formula:

a imidazolidine, an imidazoline, an isothiourea derivative represented by the formula:

a mercaptocarboxylic acid, a mercaptoacetyl amide, an alkyne compound represented by the formula:

a hydroxyalkyl carboxylic acid, a hydroxy heterocyclic carboxylic acid, a thiaalkyl compound represented by the formula:

[(XVI)] X -- S -- Z

a dithiaalkyl compound represented by the formula: [(XVII)] X -- S -- S -- Z

an oligothiaalkyl compound represented by the formula:

[(XVIII)]X -- S -- Y--S --.sub.n Z' oxalic acid, a phenylene dioxy dialkyl carboxylic acid, succinic acid, or a polymer containing a ligand atom having the property of complexing a metal suitable for physical development, wherein R.sub.1, R.sub.2, R.sub.4 and R.sub.5 are hydrogen, alkyl containing one to 20 carbon atoms, acyl containing one to five carbon atoms, aryl containing six to 30 carbon atoms, or atoms completing a five- or six-member heterocyclic ring; R.sub.15 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.16 ; R.sub.16 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.17 ; R.sub.17 is --P--R.sub.18, --S--R.sub.19,

or an alkylene oxide polymer adduct or atoms completing a ring with R.sub.16 wherein R.sub.18, R.sub.19, R.sub.20 and R.sub.21 are each hydrogen, acyl containing one to five carbon atoms, or alkyl containing one to 20 carbon atoms; wherein Z or X is a five- or six-member heterocyclic ring, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or acyl containing one to five carbon atoms; Z' is Z or hydrogen; Y is alkylene containing one to five carbon atoms; n is 1 to 10.

2. An element as in claim 1 wherein said metal is silver and said metal complex is a silver complex.

3. An element as in claim 1 wherein said stable metal-organic complex of a metal suitable for physical development is a stable complex of silver with a thiazoline-2-thione.

4. A photographic element as in claim 3 in which said metal-organic complex is a complex of silver with a 4-thiazoline-2-thione, and wherein said element has a pAg range of about 2.0 to about 10.

5. An element as in claim 1 wherein said metal-organic complex is a stable silver-5-carbethoxy-3-carboxymethyl-4-methyl-4-thiazoline-2-thione complex.

6. An element as in claim 1 wherein said metal-organic complex is a stable silver-organic complex of silver with a polymer containing sulfur as a ligand atom.

7. An element as in claim 1 which contains a layer sensitive to the red region of the spectrum, a layer sensitive to the green region of the spectrum and a layer sensitive to the blue region of the spectrum.

8. An element as in claim 1 which additionally contains a binder and a hardener for said binder.

9. An element as in claim 1 which additionally contains a photographic silver halide.

10. A photographic element as in claim 1 wherein said metal is silver and said element has a pAg range of about 2.0 to about 10.

11. A photographic element as in claim 1 wherein said metal is silver, said element has a pAg range of about 2.0 to about 10 and the molar ratio of the organic moiety to said metal in said metal-organic complex is about 0.2 to about 7.

12. In a photographic process comprising physical development of a latent image in a radiation-sensitive silver-dye complex which has the property of forming active sites for physical development upon exposure to radiation which has the property of forming active sites for physical development upon exposure to radiation, employing a source of metal for said physical development, the improvement comprising employing a stable source of metal for said physical development which is a stable metal complex of a metal suitable for physical development with a compound which is:

a thiazoline thione, a thiazolidine thione, a thiopyrimidine, a dithiocarbamate represented by the formula: [(V)]

a thiourea derivative represented by the formula: [(VI)]

a pseudothiohydantoin represented by the formula: (VIII)]

an imidazolidine, an imidazoline, an isothiourea derivative represented by the formula: [(XI)]

a mercaptocarboxylic acid, a mercaptoacetyl amide, an alkyne compound represented by the formula: [(XIV)]

a hydroxyalkyl carboxylic acid, hydroxy heterocyclic carboxylic acid, a thiaalkyl compound represented by the formula:

[(XVI)] X -- S -- Z

a dithiaalkyl compound represented by the formula:

[(XVII)] X -- S -- S -- Z

an oligothiaalkyl compound represented by the formula:

[(XVIII)] X -- S -- Y-S --.sub.n Z'

oxalic acid, a phenylene dioxy dialkyl carboxylic acid, succinic acid, or a polymer containing a ligand atom having the property of complexing a metal suitable for physical development, wherein R.sub.1, R.sub.2, R.sub.4 and R.sub.5 are hydrogen, alkyl containing one to 20 carbon atoms, acyl containing one to five carbon atoms, aryl containing six to 30 carbon atoms, or atoms completing a five- or six-member heterocyclic ring; R.sub.15 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.16 ; R.sub.16 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.16 ; R.sub.16 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.17 ; R.sub.17 is --O--R.sub.18, --S--R.sub.19,

or an alkylene oxide polymer adduct or atoms completing a ring with R.sub.16, wherein R.sub.18, R.sub.19, R.sub.20, and R.sub.21 are each hydrogen, acyl containing one to five carbon atoms, or alkyl containing one to 20 carbon atoms; wherein Z or Z is a five- or six-member heterocyclic ring, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or acyl containing one to five carbon atoms; Z' is Z or hydrogen; Y is alkylene containing one to five carbon atoms; n is 1 to 10.

13. A photographic process as in claim 12 comprising physical development of a latent image in an element which contains a layer sensitive to the red region of the spectrum, a layer sensitive to the green region of the spectrum, and a layer sensitive to the blue region of the spectrum.

14. A photographic process as in claim 12 wherein said metal is silver and said metal complex is a silver complex.

15. The process of claim 14 wherein the photographic process is a diffusion transfer process.

16. A photographic composition comprising a radiation-sensitive silver-dye complex and a stable source of metal for physical development of a latent image in said silver-dye complex, said stable source of metal being a stable metal-organic complex of a metal suitable for physical development with a compound which is:

a thiazoline thione, a thiazolidine thione, a thiopyrimidine, a dithiocarbamate represented by the formula: [(V)]

a thiourea derivative represented by the formula:

a pseudothiohydantoin represented by the formula: [(VIII)]

an imidazolidine, an imidazoline, an isothiourea derivative represented by the formula: [(XI)]

a mercaptocarboxylic acid, mercaptoacetyl amide, an alkyne compound represented by the formula: [(XIV)]

a hydroxyalkyl carboxylic acid, a hydroxy heterocyclic carboxylic acid, a thiaalkyl compound represented by the formula:

[(XVI) X -- S -- Z

a dithiaalkyl compound represented by the formula:

[(XVII) X-- S -- S -- Z

an oligothiaalkyl compound represented by the formula:

[(XVIII)] X -- S -- Y-S --.sub.n Z ' oxalic acid, a phenylene dioxy dialkyl carboxylic acid, succinic acid, or a polymer containing a ligand atom having the property of complexing a metal suitable for physical development, wherein R.sub.1, R.sub.2, R.sub.4 and R.sub.5 are hydrogen, alkyl containing one to 20 carbon atoms, acyl containing one to five carbon atoms, aryl containing six to 30 carbon atoms, or atoms completing a five- or six-member heterocyclic ring; R.sub.15 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.16 ; R.sub.16 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.17 ; R.sub.17 is --O--R.sub.18, --S--R.sub.19,

or an alkylene oxide polymer adduct or atoms completing a ring with R.sub.16 wherein R.sub.18, R.sub.19, R.sub.20 and R.sub.21 are each hydrogen, acyl containing one to five carbon atoms, or alkyl containing one to 20 carbon atoms; wherein Z or X is a five- or six-member heterocyclic ring, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or acyl containing one to five carbon atoms; Z' is Z or hydrogen, Y is alkylene containing one to five carbon atoms; n is 1 to 10.

17. A photographic composition as in claim 16 wherein said metal-organic complex is a silver complex.

18. A photographic composition as in claim 16 wherein said metal-organic complex is a complex of silver with a 4-thiazoline-2-thione.

19. A photographic composition as in claim 16 wherein said metal is silver and said composition has a pAg range of about 2.0 to about 10.

20. A photographic composition as in claim 16 which additionally contains a photographic silver halide.

21. A physical developer composition comprising (a) a silver halide developing agent, and (b) a stable source of metal for physical development which is a stable metal organic complex of a metal suitable for physical development with a compound which is:

a thiazoline thione, a thiazolidine thione, a thiopyrimidine, a dithiocarbamate represented by the formula: [(V)]

a thiourea derivative represented by the formula:[(VI)]

a pseudothiohydantoin represented by the formula: [(VIII)]

an imidazolidine, an imidazoline, an isothiourea derivative represented by the formula: [(XI)]

a mercaptocarboxylic acid, a mercaptoacetyl amide, an alkyne compound represented by the formula; [(XIV)]

a hydroxyalkyl carboxylic acid, a hydroxy heterocyclic carboxylic acid, a thiaalkyl compound represented by the formula:

[(XVI)] X -- S -- Z

a dithiaalkyl compound represented by the formula:

[(XVII)]X -- S -- S -- Z

an oligothiaalkyl compound represented by the formula:

[(XVIII)] X -- S-- Y-S --.sub.n Z' oxalic acid, a phenylene dioxy dialkyl carboxylic acid, succinic acid, or a polymer containing a ligand atom having the property of complexing a metal suitable for physical development, wherein R.sub.1, R.sub.2, R.sub.4 and R.sub.5 are hydrogen, alkyl containing one to 20 carbon atoms, acyl containing one to five carbon atoms, aryl containing six to 30 carbon atoms, or atoms completing a five- or six-member heterocyclic ring; R.sub.15 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.16 ; R.sub.16 is hydrogen, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or atoms completing a ring with R.sub.17 ; R.sub.17 is --O--R.sub.18, --S--R.sub.19,

or an alkylene oxide polymer adduct or atoms completing a ring with R.sub.16 wherein R.sub.18, R.sub.19, R.sub.20 and R.sub.21 are each hydrogen, acyl containing one to five carbon atoms, or alkyl containing one to 20 carbon atoms; wherein Z or X is a five- or six-member heterocyclic ring, aryl containing six to 30 carbon atoms, alkyl containing one to 20 carbon atoms, or acyl containing one to five carbon atoms; Z' is Z or hydrogen; Y is alkylene containing one to five carbon atoms; n is 1 to 10.

22. The physical developer composition of claim 21 wherein the composition is an alkaline solution.

23. A physical developer composition as in claim 21 wherein said metal complex is a silver complex.