Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
  • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
  • G03C1/08—Sensitivity-increasing substances
  • G03C1/28—Sensitivity-increasing substances together with supersensitising substances

Definitions

• the invention relates to light sensitive photographic layers, in particular to silver halide emulsion layers, which are spectrally sensitized with a mixture of sauthylium dyes and acid mercapto compounds.
• sauthylium dyes are capable of speclrally sent-iitiring silver halide.
• the sensitization maximum of these dyes normally lies in the green region of the spectrum-
• the intensity of sensitization of these dyes is only very slight, and these dyes have therefore hitherto not been used in practice for the production of photographic film-s and papers.
• X is an oxygen, sulfur or selenium atom
• R, and R each is an amino group which may be monosubstituted or disubstituted, e.g. with alkyl groups containing up to 6 carbon atoms, cycloalltyl groups such as cyclohexyl, aralkyl groups such as benzyl, or aryl groups such as phenyl; two radicals attached to the same nitrogen atom may together with this nitrogen atom form a S-membered, tiruember ed or i-mem bered heterocyclic ring which may contain a further heteroatotn, such as pyrrolidine, piperidine, hettamethyleneintine or morpholine:
• the acid mereapto compounds which are used together with the xan-thyliunt dyes according to the invention may be represented by the following general formula:
• acid-Z-SH in which 2'. is an isocyclic aromatic group such as a benzene or naphthalene group or an unsubstituted or substituted heterocyclie group consisting of a fi -membered or o membered heterocyclic ring and, if desired, benzene or naphthalene rings attached thereto by condensation, e.g.
• acid is an acid group which is attached to 2 either directly or via one or more vinyl groups, e.g. -SO H, sSO T, C-OOH, -PO H --NHS O R or SOgNH R in which R denotes an alkyl or aryl group; the acid groups may also be present in the anionic form as metal salts, preferably as alkali metal or alkaline earth metal salts or as salts of organic nitrogen bases.
• the acid mercapto compounds are also known. The following compounds, for example, having been found to be suitable for the purpose of the present invention:
• the usual silver halide emulsions may be spectrally sensitized by means of the mixtures according to the invention.
• the silver halide contained in these emulsions is generally silver chloride, silver bromide or a mixture of these, if desired with a small silver iodide content of up to 10 mols percent.
• the binder used for the photographic layers is preferably gelatin although it may be partly or completely replaced by other natural or synthetic binders.
• Suitable natural binders are e.g. alginic acid and its derivatives such as salts, esters or amides, cellulose derivatives such as carboxymethylcellulose, alkyl cellulose such as hydroxyethyl cellulose, starch or derivatives thereof such as ethers or esters or carragheenates.
• Examples of synthetic binders are polyvinyl alcohol, partly saponified polyvinyl acetate and polyvinyl pyrrolidone.
• the sensitizing mixture of xanthylium dye and acid mercapto compound may be added to the emulsions at any stage of their production, e.g. during precipitation of the silver halide, before or after the chemical ripening and preferably before casting.
• the conventional methods used for this are well known in the art.
• Both the xanthylium dyes and the mercapto compounds are added to the emulsions in the form of solutions.
• the solvent must, of course, be compatible with gelatin and must not have any adverse influence on the photographic properties of the emulsion. Water and alcohol are particularly suitable for use as solvents.
• the quantity of sensitizing xanthylium dye added may vary within wide limits, e.g. between 2 and mg.
• the quantity of acid mercapto compound added may also vary within wide limits, e.g: between 10 and 2000 mg. and preferably between 50 and 500 mg./kg. of silver halide emulsion. Particularly good results are achieved when the quantity of acid mercapto compound is a multiple of the quantity of xanthylium dye, e.g. 2 to 50 times the quantity of dye.
• the advantageous efi'ect of the acid mercapto compounds is all the more astonishing in view of the high concentrations used since it is generally known that mercapto compounds act as stabilizers and when used in high concentrations severely impair the general sensitivity of silver halide emulsions.
• the two components of the sensitizing mixtures according to the invention may be added to the emulsions successively from separate solutions or they may be added simultaneously from a common solution.
• the emulsions may also be chemically sensitized, e.g. by adding compounds which contain sulfur at the stage of chemical ripening, for example allylisothiocyanate, allylthiourea, or sodium thiosulfate.
• Reducing agents e.g. the tin compounds described in Belgian patent specification Nos. 493,464 and 568,687 polyamines such as di ethylene triamine or aminomethanesulfinic acid derivatives, e.g. according to Belgian patent specification No. 547,323, may also be used as chemical sensitizers.
• Noble metals and compounds of noble metals such as gold, platinum, palladium, iridium, ruthenium or rhodium are also suitable as chemical sensitizers. This method of chemical sensitization has been described in the article by R. Koslowsky, Z. Wiss. Phot. 46, 65-72 (1951).
• the emulsions may also be sensitized with polyalkylene oxide derivatives, e.g. with polyethylene oxide having a molecular weight of between 1,000 and 20,000, or with condensation products of alkylene oxides and aliphatic alcohols, glycols, cyclic dehydration products of hexitols or with alkyl substituted phenols, aliphatic carboxylic acids, aliphatic amines, aliphatic diamines and amides.
• the condensation products have a molecular weight of at least 700 and preferably more then 1,000.
• the emulsions may contain the usual stabilizers, e.g. homopolar or salt-type compounds of mercury which have aromatic or heterocyclic rings such as mer captotriazoles, simple mercury salts, sulphonium mercury double salts and other mercury compounds.
• stabilizers e.g. homopolar or salt-type compounds of mercury which have aromatic or heterocyclic rings such as mer captotriazoles, simple mercury salts, sulphonium mercury double salts and other mercury compounds.
• Azaindenes especially tetraor penta-azaindenes and especially those which are substituted with hydroxyl or amino groups are also suitable for use as stabilizers. Compounds of this type have been described in the article by Birr. Z. Wiss. Phot. 47, 2-58 (1952).
• Other suitable stabilizers include heterocyclic mercapto compounds, e.g. phenylmercaptotetrazole, quaternary benzothiazole derivatives, or benzotriazole.
• a special advantage of the photographic material which has been senstized according to the invention consists in its insensitivity to the usual additives such as color forming couplers or dyes which can be bleached.
• the emulsions may be hardened in the usual manner, for example with formaldehyde or halosubstituted aldehydes which contain a carboxyl group, eg mucobromic acid, diketones, methanesnlfonic acid esters or dialdehydes.
• formaldehyde or halosubstituted aldehydes which contain a carboxyl group, eg mucobromic acid, diketones, methanesnlfonic acid esters or dialdehydes.
• EXAMPLE 1 A silver chloride emulsion (prepared according to Baker, Photogr. Em. Tech. American Photogr. Publishing (30., Boston, Mass, 1948, page 217) is cast on a layer support and exposed when dry behind a yellow filter GG 435 (made by the firm of Schott) (thickness of glass 3 mm. absorption edge 435 nm.) and a grey wedge with :5 steps and is then processed in the usual manner.
• GG 435 made by the firm of Schott
• a grey wedge with :5 steps is then processed in the usual manner.
• the sensitivity is considerably increased by the addition of 2 mercaptonaphtho-[1,8-de]-oxazine-8-sulfonic acid sodium (I), 2-mercapto-naphtho-[1,8-de1-oxazine-5- sulfonic acid sodium (H) or 2-mercapto-naphtho-[1,8-de1- oxazine-G-snlfonic acid sodium (III) (in each case as a 0.5% aqueous solution), as can be seen from Table I.
• the addition of the acid mercapto compound therefore results in an increase in sensitivity by up to 12 steps (this corresponds to 16 times the sensitivity) compared with an emulsion which has only been sensitized with Pyronin B, and in the case of storage under tropical conditions there is an increase by 16 steps (corresponding to 40 times the sensitivity).
• Rhodamine B shows, in 1 kg. of a silver chloride emulsion, a very slight sensitization at about 577 nm.
• the sensitivity achieved with it and that achieved after the addition of the following mercapto compounds are shown in Table II:
• non-acid mercapto compounds A, B and C used as stabilizers are used here for comparison.
• coupler l-(4-phenoXy-3'-sulfophenyl)-3'-heptodecylpyrazolone-(S) are as follows:
• EXAMPLE 11 in which 6 mg. of Pyronin B in methanolic solution (1:2000) X is an oxygen, sulphur or selenium atom, are added to 1 kg. of an ammonia emulsion as described R is a hydrogen atom or is an alkyl, aralkyl, cycloalkyl in Example 5.
• R is a hydrogen atom or is an alkyl, aralkyl, cycloalkyl in Example 5.
• the following sensitivities are obtained bcor aryl group, hind yellow filter L 489: R and R, which may be the same or different are an Steps V5 amino group, the nitrogen atom of which may be Dye alone 10 monoor (ii-substituted with alkyl groups containing Dye+200 mg.
• a photographic material which comprises at least acid Z SH one silver halide emulsion layer that contains both (1) a xanthylium dye of the formula: m whch Z is phenylene or a heterocyclic ring selected from the R group consisting of benzoxazole, naphthoxazole, I benzothiazole, naphthothiazole, benzoselenazole, R3 Q naphthoselenazole, benzirnidazole, naphthoimidazole,
• 1 1 1 2 acid is an acid group selected from the group consist- 5.
• a material as claimed in claim 4 which comprises ing of SO H, -SO H, COOH, -PO H 50 to 500 mg./kg. of acid mercapto compound.
• a material as clalmed in claim 1 WhlCh comprlses 1n 3 248 219 4/1965 Jacobs 96 120 the silver halide emulsion layer 2 to 100 mg. of xanthy- 7/1969 Riester 96 107 lium y P kilflgl'am 0f emulsion 3, 579 3 5 5 1971 Jones 9 107 3.
• a material as claimed in claim 2 which comprises 5 to a s of Xanthylium y J. TRAVIS BROWN, Primary Examiner 4.
• a material as claimed in claim 1 which comprises 10 to 2,000 mg. of acid mercapto compound per kg. of US. Cl. X.R.

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• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Cited By (9)

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  • BE BE756085D patent/BE756085A/de unknown
• 1969
  • 1969-09-12 DE DE19691946263 patent/DE1946263A1/de active Pending
• 1970
  • 1970-08-26 US US67256A patent/US3687678A/en not_active Expired - Lifetime
  • 1970-09-10 GB GB4329170A patent/GB1319967A/en not_active Expired
  • 1970-09-11 FR FR7033144A patent/FR2061349A5/fr not_active Expired

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