US3554758A

US3554758A - Photographic light-sensitive material

Info

Publication number: US3554758A
Application number: US688659A
Authority: US
Inventors: Jozef Frans Willems; Robrecht Julius Thiers
Original assignee: Agfa Gevaert NV
Current assignee: Agfa Gevaert NV
Priority date: 1967-03-06
Filing date: 1967-12-07
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12
Also published as: GB1189129A; BE709197A

Abstract

A LIGHT-SENSITIVE MATERIAL COMPRISING A SILVER HALIDE EMULSION LAYER CONTAINING AN IODONIUM COMPOUND CORRESPONDING TO ONE OF THE FOLLOWING FORMULAE:

(PHENYL)2-I(+) Y(-) . HGX2 AND

DIBENZIODOLIUM Y(-) . HGX2

WHEREIN Y- REPRESENTS AN ANION AND X REPRESENTS A HALOGEN ATOM HAVING AN ATOMIC NUMBER GREATER THAN 9 IS DESCRIBED. THE IODONIUM COMPOUND STABILIZES THE EMULSION AGAINST ANY INCREASE IN FOG WITHOUT SUBSTANTIAL DESENSITIZATION OF THE EMULSION.

Description

United States Patent 3,554,758 PHOTOGRAPHIC LIGHT-SENSITIVE MATERIAL Jozef Frans Willems, Wilrijk, Robrecht Julius Thiers, Brasschaat, Belgium, assignors to Gevaert-Agfa N.V., Mortsel, Belgium, a company of Belgium No Drawing. Filed Dec. 7, 1967, Ser. No. 688,659 Claims priority, application Great Britain, Mar. 6, 1967, 10,373/ 67 Int. Cl. G03c N34 US. Cl. 96109 6 Claims ABSTRACT OF THE DISCLOSURE A light-sensitive material comprising a silver halide emulsion layer containing an iodonium compound corresponding to one of the following general formulae:

and

wherein Y" represents an anion and X represents a halogen atom having an atomic number greater than 9 is described. The iodonium compound stabilizes the emulsion against any increase in fog without substantial desensitization of the emulsion. t

This invention relates to improved light-sensitive silver halide emulsions.

Light-scnsitive silver halide emulsions are in general silver halide emulsions against spontaneous formation and growth of fog known as chemical fog during prolonged storage or storage at high temperatures and humidities or during development to maximum contrast and speed. Indeed, the fog increases with the degree and temperature of development, and, in constant development circumstances, with the time the light-sensitive emulsion is stored and with the temperature and the relative humidity of the atmosphere wherein the emulsion is stored. It is evident that a light-sensitive emulsion should be obtained which is as stable as possible at high temperature and highrelative humidity for instance in view of its use in tropical countries.

It is known to protect light-sensitive silver halide emulsions against the growth of chemical fog during storage by addition of stabilizers of the triazolopyrimidine type (azaindolizines). Heterocyclic thioxo and mercapto compounds too have been proposed for this purpose but show the disadvantage of impairing the sensitivity'and gradation. The same disadvantageous influence on the sensitivity occurs with the known mercury compounds such as simple inorganic mercury salts, addition complexes of mercury with amines, organic mercury salts and heterocyclic mercury compounds. Indeed, these com pounds, when used in the concentration necessary for obtaining a suflicient antifogging action, have a considerable desensitizing efi'ect.

3,554,758 Patented Jan. 12, 1971 It is also known that emulsions stabilised with compounds of the triazolopyrimidine type still show a tendency to fog formation in extreme storage circumstances i.e. at very high temperatures and humidities and in extreme development circumstances e.g. rapid processing at elevated temperatures. The addition to these emulsions of the above known mercury compounds reduces the fogging tendency but, as mentioned above, at the cost of a reduction of the sensitivity.

It has now been found that when incorporating in a light-sensitive material comprising a silver halide emulsion layer double salts of mercury(II) compounds and iodonium compounds, corresponding to one of the following general formulae:

Y- represents an anion e.g. a halogen anion, a nitrate anion, a bisulphate anion, etc., and

X represents a halogen atom, and wherein the aromatic nuclei of said compounds include the substituted derivatives thereof e.g. substituted with an alkyl radical, a halogen atom, an alkoxy radical, a cyano radical, an acyl radical or an acylamino radical.

The compounds of use according to the present invention can be prepared by reaction of the iodonium compound with the mercury(II) halide as is illustrated by the following preparations.

PREPARATION I: COMPOUND 1 A 31.6 g. (0.1 mole) of diphenyl iodonium chloride are dissolved in 300 ml. of methanol by refluxing. To the and wherein:

boiling solution is added dropwise a solution of 27.1 g. (0.1 mole) of mercury(II) chloride in 100 ml. of methanol. A precipitate forms immediately. After the addition of the mercury(II) chloride solution refluxing of the mixture is continued for 1 hour. The precipitate formed does not dissolve anymore. Then the suspension is cooled and the solid product is filtered by suction and washed with ether. The yield before recrystallization is 57.5 g. The crude product is recrystallized from dimethylformamide/ ethanol (6:4). Yield: 38 g. Melting point: 208-210 C.

PREPARATION II: COMPOUND 3 15.8 g. (0.05 mole) of diphenyl iodonium chloride are dissolved in 150 ml. of methanol by refluxing. To the boiling solution is added dropwise a solution of 18 g. (0.05 mole) of mercury(II) bromide in 200 ml. of methanol. A white precipitate forms immediately. After the addition of the mercury(II) bromide solution refluxing is continued for 4 hours. The precipitate formed does not dissolve anymore. Then the suspension is cooled and the solid product is filtered by suction and washed with ether. The yield before recrystallization is 32 g. The crude product is recrystallized from dimethylformamide/methanol (3:7). Yield: 26 g. Melting point: 155 C.

As compared with the known mercury compounds used as stabilizers the mercury(II) compounds according to the present invention when used in the appropriate concentration do not cause or only to a slight extent a decrease in sensitivity.

The antifoggants according to the present invention are particularly suitable for use in combination with compounds which sensitize the emulsion by development acceleration for example compounds of the polyoxyalkylene type such as alkylene oxide condensation products as described among others in United States Pats. 2,531,832 and 2,533,990, in United Kingdom Pats. 920,637, 940,051, 945,340 and 991,608 and in Belgian Pat. 648,710 and onium derivatives of amino-N-oxides.

The stabilizers according to the inventions can also be used in combination with other known stabilizer for instance with heterocyclic nitrogen containing thioxo compounds such as benzothiazoline-Z-thione and 1-phenyl-2- tetrazoline-S-thione, with other mercury compounds, and, as said above, preferably with compounds of the hydroxytriazolopyrimidine type (azaindolizines).

The stabilizers according to the present invention may be incorporated into any type of light-sensitive material comprising a silver halide emulsion layer e.g. a spectrally sensitized or non-sensitized emulsion layer, an X-ray emulsion layer or an emulsion layer sensitive to infrared radiation. They may be incorporated into high-speed negative materials as well as into rather low speed positive materials. Various silver salts may be used as light-sensitive salt e.g. silver bromide, silver iodide, silver chloride, or mixed silver halides e.g. silver chloro-bromide or silver bromo-iodide.

The silver halides are dispersed in the common hydrophilic colloids such as gelatin, casein, zein, polyvinyl alcohol, carboxymethylcellulose, alginic acid, etc., gelatin however, being favoured.

The stabilizing agents are generally incorporated into the silver halide emulsion layer of the light-sensitive material; they may be added to the emulsion during no matter what step of emulsion preparation; however, they are preferably added to the photographic emulsion after the chemical ripening and just before coating of the emulsion. The addenda according to the present invention are incorporated into the photographic emulsions according to the methods well known in emulsion preparation. For instance they can be added to the emulsion in the form of a solution or of a dispersion according to the methods applied for incorporating colour couplers in the emulsion.

Instead of incorporating the compounds of the invention into the emulsion layer they can also be incorporated into a water-permeable layer e.g. a gelatin covering layer or an intermediate layer.

The amount of mercury(II) compound employed in the light-sensitive silver halide material depends on the particular type of emulsion and the desired effect and can vary within very wide limits. The optimum amount of mercury(II) compound to be added can be determined for each particular type of material in a very simple way by application of the usual tests. Usually said compounds are employed in a ratio of about 0.1 mg. to about 30 mg. per mole of silver halide, preferably from 0.5 mg. to 10 mg. per mole of silver halide.

The light-sensitive emulsions may be chemically as well as optically sensitized. They may be chemically sensitized by effecting the ripening in the presence of small amounts of sulphur containing compounds such as allylthiocyanate, allyl thiourea, sodium thiosulphate, etc. The emulsions may also be sensitized by means of reductors for instance tin compounds as described in our French patent specification 1,146,955 and in our Belgian patent specification 568,687, imino-amino methane sulphinic acid compounds as described in our British patent specification 789,823 and small amounts of noble metal compounds such as of gold, platinum, palladium, iridium, ruthenium and rhodium.

Other addcnda such as hardening agents, wetting agents, plasticizers, colour couplers, developing agents and optical sensitizers can be incorporated into the emulsion in the usual way.

The following examples illustrate the present invention.

Example 1 A high sensitive gelatino silver bromoiodide emulsion (i4.5 moles percent of iodide) is divided into four aliquot portions A, B, C and D.

To emulsion portion B is added per mole of silver halide 0.6 l0 millimole (1.5 mg.) of mercury(II) cyanide, to emulsion portion C 0.6 10 millimole (3.5 mg.) of compound 1 and to emulsion portion D 0.6 10 millimole (4.6 mg.) of compound 3. The four emulsions are then coated on a subbed cellulose triacetate support and dried whereupon the four materials thus obtained are stored for 5 days in an atmosphere of 57 C. and 34% of relative humidity.

The stored materials as well as four identical freshly prepared materials are exposed and developed for 5 minutes at 20 C. in a developing bath with the following composition:

Water-800 ccs. p-Monomethylaminophenol sulphate-4.5 g. Sodium sulphite (anhydrous)-50 g. Hydroquinone--6 g.

Sodium carbonate (anhydrous)32 g. Potassium bromide2 g.

Water up to 1000 ccs.

After the treatment in a stop bath, rinsing and fixing of the materials the following sensitometrie results are obtained.

TABLE Freshly prepared materials Stored materials Relative Relative Gradaspeed Gradaspeed Material Fog tion (percent) Fog tion (percent) The speed is given in relative values (i.e. in percent) In respect of the absolute speed of an emulsion to which no mercury(Il) compound was added.

conditioned in a moist atmosphere of about 100% of relative humidity. Thereupon the materials are packed in aluminium-laminated paper and stored for 1 week at 57 C.

5 The following sensitometric results are obtained.

TABLE Freshly prepared materials Fog produeed in Amount of stabilizer per Grada- Relative stored Material mole of silver halide Fog tion speed materials A None 0. 11 2. 32 100 0. 32 B 2.3 mg. of compound 1 0. 12 2. 12 100 0. 14 C 2.6 mg. of compound 3. 0. 12 2. 05 103 0. 14

Example 2 We claim:

ing to the formula:

wherein x has a value of about 135 and 2 g. of saponin as coating aid, is divided into 3 aliquot portions.

To two of these emulsion portions is added an amount of stabilizer according to the present invention as listed in the table below.

The three emulsions are coated on both sides of a cellulose triacetate support, which has been provided on both sides with a subbing layer, in such a way that per sq. m. an amount of silver halide equivalent to 36 g. of silver nitrate (both sides taken together) is present.

The emulsion layers are then overcoated with a gelatin antistress layer.

The three materials, A, B and C obtained are then exposed to X-rays with an X-ray radiation source of 80 kv. and developed for 8 min. at 26 C. in a common X- ray developer having the following composition:

Water800 ccs. p-Monomethylaminophenol hemisulphate--4 g. Hydroquinone g.

Anhydrous sodium sulphite65 g.

Anhydrous sodium carbonate--45 g.

Potassium bromide-5 g.

Water up to 1000 ccs.

The results obtained are listed in the following table.

A gelatino silver bromoiodide emulsion as described in Example 2 is divided into 3 aliquot portions.

To two of these emulsion portions is added an amount of mercury(II) compound as listed in the table below.

The three emulsions are then further treated as described in Example 2 and the resulting materials are 1. A photographic light-sensitive silver halide emulsion including at least one compound corresponding to one of the general formulae:

wherein Y- represents an anion and X represents a halogen atom having an atomic number greater than 9, said compound being present in an amount sufficient to stabilize said emulsion with regard to fogging.

2. A photographic emulsion according to claim 1, wherein Y represents a halogen anion, a bisulphate anion or a nitrate anion.

3. Photographic material according to claim 1, whereand in said compound is present in an amount of from 0.1

mg. to 30 mg. per mole of silver halide.

4. A photographic emulsion according to claim 1, wherein said emulsion additionally includes a stabilizer of the hydroxy-triazolopyrimidine type.

5. A photographic emulsion according to claim 1, wherein said emulsion additionally includes a development accelerator of the polyoxyalkylene type.

6. A photographic emulsion according to claim 1, wherein said emulsion is a gelatino silver halide emulsion.

References Cited UNITED STATES PATENTS WILLIAM D. MARTIN, Primary Examiner R. M. SPEER, Assistant Examiner US. Cl. X.R. 96l08 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 554, 758 Dated January 12, 1971 Inventor(s) JOZEF FRANS WILLEMS and ROBRECHT JULIUS THEIRE It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, claim 1, second formula set forth as Y'. HgY should read Y'. HgX

claim 3, line 1, "Photographic material" should read A photographit emulsion Signed and sealed this 7th day of March 1972.

(SEAL) Attest:

ROBERT GOTTSCHALK EDWARD M.FLETCHER ,JR.

Commissioner of Patents Attesting Officer