Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D257/00—Heterocyclic compounds containing rings having four nitrogen atoms as the only ring hetero atoms
  • C07D257/02—Heterocyclic compounds containing rings having four nitrogen atoms as the only ring hetero atoms not condensed with other rings
  • C07D257/04—Five-membered rings
• • 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
  • G03C1/035—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein characterised by the crystal form or composition, e.g. mixed grain
• • 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
  • G03C1/34—Fog-inhibitors; Stabilisers; Agents inhibiting latent image regression
  • G03C1/346—Organic derivatives of bivalent sulfur, selenium or tellurium

Definitions

• This invention relates to photographic materials and their preparation.
• this invention relates to photographic emulsions comprising fogged internal image silver halide grains and unfogged surface latent image grains, which emulsions exhibit good resistance to fog on development.
• this invention relates to a photographic element comprising an emulsion layer in which there are fogged internal latent image grains and unfogged surface latent image grains.
• silver halide crystals of the type employed in photographic emulsions have both surface and internal Sensitivity to light, and that these types of sen: sitivity may vary considerably among dilferent emulsions.
• Silver halide grains having a high ratio of surface-to-internal sensitivity comprise the silver halide grains used in the majority of photographic emulsions.
• Silver halide grains having a high ratio of internal-tosurface sensitivity are also Well known but are less generally employed in practice. Emulsions containing such grains are described, for example, in Mees The Theory of the Photographic Process, p. 221 (Revised edition), 1954; in Journal of the Optical Society of America, 31 (1941), p. 382 and in Davey and Knott U.S. Patent 2,592,250, issued Apr. 8, 1952.
• Another object of this invention is to provide photographic silver halide emulsions which exhibit good sensitivity and contrast with very low fog.
• Still another object of this invention is to provide photographic silver halide emulsions which are very atent 3,397,987 Patented Aug. 20, 1968 highly sensitized with onium salts and/or alkylene oxide polymers, which emulsions still do not exhibit objectionable fog upon development.
• a method for inhibiting fog upon development of a photographic silver halide emulsion comprising fogged internal, image silver halide grains and unfogged surface latent image silver halide grains using a heterocyclic nitrogen compound containing a mercapto function, as described herein.
• a significant feature of this invention is that the heterocyclic compounds employed in the practice of this invention inhibit fog in the photographic silver halide emulsions upon development without substantially diminishing speed.
• other mercepto compounds which do not contain a heterocyclic ring do not'have the desired results with the photographic silver halide emulsions of U.S. Patents 2,996,382 and 3,178,282, as shown by Example 4, which follows.
• structurally closely related heterocyclic compounds which do not contain the required mercapto function cannot be used in the practice of this invention, as shown by Example 5
• the hetero-, cyclic nitrogen compound employed in the practice of this invention is adsorbed to the fogged internal image silver halide grains. If the surface latent image silver halide grains are treated with the heterocyclic nitrogen compound there is a substantial loss in speed, as illustrated by Example 1 which follows.
• the surface latent image emulsions used in the practice of this invention have a relatively high degree of sur face sensitivity and relatively low internal sensitivity while the internal image emulsions used have a high de-v gree of internal sensitivity but relatively low surface sen,
• the surface latent image emulsions contain silver halide grains that have substantial surface sensitivity and form latent images when exposed to light on the surface thereof. Unlike the fogged silver halide internal latent image grains described herein, the surface latent image silver halide grains are substantially unfogged. Any of the photographic silver halides can be used in the preparation of the surface latent image emulsions and include, for example, silver bromide, silver bromoiodide, silver chloroiodide, silver chlorobromoiodide, silver chloride, silver chlorobromide and the like, the preferred halide being 'bromoiodide.
• test portion of the emulsion when measured according to normal photographic testing techniques by coating a test portion of the emulsion on a transparent support, exposing the test portion to a light intensity scale for a fixed time between 0.01 and 1 second and development for 6 minutes at 68 F. in
• Developer A as hereinafter defined, have a sensitivity
• Developer A is the usual type of surface image developer and Developer B is an internal developer having high silver halide solvent activity.
• the degree of internal sensitivity of the surface latent image emulsions is subject to wide variation.
• the surface latent image emulsions can have relatively little internal sensitivity or they can have a fair amount of internal sensitivity, but preferably not greater than the surface activity.
• the surface latent image emulsions can have high or low contrast since useful effects can be obtained with both types of emulsions.
• the surface latent image emulsions can also be characterized as having a D greater than about 0.50 when coated at a coverage of about 540 mg. silver per square foot, exposed to a step wedge and processed for 12 minutes in Developer C as hereinafter de fined.
• surface image silver iodo-halide surface latent image emulsions such as silver bromoiodide emulsions.
• Such emulsions can contain varying concentrations of iodide although especially useful results are obtained with such iodohalide surface latent image emulsions containing from about 0.5 to about 99 mole percent iodide.
• the internal surface latent image photographic silver halide emulsions employed in the practice of this invention contain fogged internal latent image siliver grains. Any of the photographic silver halides can be used in the preparation of these internally fogged grains and inelude, for example, silver bromide, silver chlorobrornoiodide, silver chlorobrornide, silver chloride and the like.
• suitable emulsions that form latent images internal to the silver halide grains reference is made to Davey et al. U.S. Patent 2,592,250, issued Apr. 8, 1952, Luckey and Hoppe U.S. Patent 2,996,382, issued Aug. 15, 1961, and Luckey and Hoppe U.S. Patent 3,178,282, issued Apr. 13, 1965.
• such emulsions are those which, when measured according to normal photographic techniques in their unfogged state by coating a test portion of the emulsion on a transparent support, exposing to a light intensity scale having a fixed time between 0.1 and 1 second, bleaching 5 minutes in 0.3% potassium ferricyanide solution at 65 F. and developing for about 5 minutes at 65 F. in Developer B described hereinafter, have a sensitivity measured at a density of 0.1 above fog appreciably greater (for example, at least 1.4 log E greater) than the sensitivity of an identical test portion which has been exposed in the same way and developed for 6 minutes at 68 F. in Developer A described hereinafter.
• the internal image emulsions employed in the practice of this invention are fogged partly or completely before use.
• the fogging is generally sufiicient to give a density of at least 0.05 when one mole (AgX) of the fogged emulsion is coated in a blend with 3 moles of surface image emulsion at a total coverage of about 540 mg. of silver per square foot and processed for 5 minutes in Developer B hereinafter described.
• the surface D of the unfogged internal image emulsions is generally less than about 0.30 when the emulsions are exposed to D and processed for 8 minutes in Developer C identified hereinafter.
• the fogging of the internal image emulsions used in this invention can be elfected using any method suitable for this purpose. For example, such fogging can be accomplished by exposing the emulsion to light. Other methods such as chemical fogging methods can also be used.
• the photographic silver halide emulsions having high internal fog but low surface sensitivity can also be prepared by fogging an emulsion having both internal and surface sensitivity and then bleaching the surface image with a solution of potassium ferricyanide.
• Another means of obtaining the fogged internal image emulsion is by exposure of non-fogged internal image emulsions to high energy radiation, such as X-rays.
• the ratio of the surface latent image emulsion to the fogged internal image emulsion can be varied, depending upon the types of emulsions used, the contrast of the emulsions and other known variables. In general, quite useful results are obtained in those cases where the molar ratio of the surface image emulsion is at least equal to or greater than that of the fogged internal image emulsion. Useful results can be obtained even where the molar ratio, as explained above, is 42:1.
• the molar percent of the fogged internal image emulsion exceeds that of the surface image emulsion, such as a 1:3 ratio of surface to fogged internal image emulsion, there may be some loss of speed, although the contrast of the combination is considerably greater than that of the surface latent image emulsion. Accordingly, useful results can be obtained where the molar ratio of surface to fogged internal image emulsion varies from about 42:1 to 1:3.
• the photographic layers used in this invention can comprise blends or mixtures of surface image emulsions and fogged internal image emulsions, or these two types of emulsions can be coated in discrete layers which are in close proximity, i.e., in contiguous layers of the photographic element.
• either emulsion can be coated on top, since the fogged internal image emulsions have sufiicient transparency to enable the surface image emulsion to be placed closest to the support and still receive suificient transmitted radiation through the fogged internal latent image emulsions for exposure. Exposure of the emulsion closest to the support can also be made through the support where this is transparent.
• the surface image emulsion is preferably coated over the fogged internal emulsion.
• the two types of emulsions can be mixed as a blend and coated over an emulsion layer comprising a fogged internal image emulsion, which may be identical to or different from the fogged internal image emulsion in the blend.
• the development fog inhibitors employed in the practice of this invention are heterocyclic nitrogen compounds containing at least one mercapto function which is bonded to a carbon atom which is in the alpha position with respect to a nitrogen atom in a heterocyclic ring.
• the heterocyclic nucleus of such compounds contains one or more heterocyclic rings wherein the heterocyclic atoms (i.e., atoms other than carbon, including nitrogen, oxygen, sulfur, selenium and tellurium) are members of at least one heterocyclic ring.
• the heterocyclic atoms are members of a single heterocyclic ring which can be fused or condensed to one or more rings which do not contain heterocyclic atoms.
• diheterocyclic nitrogen compounds contain fused or condensed heterocyclic rings in which the heterocylic atoms are members of two heterocyclic rings.
• Suitable heterocyclic nitrogen compounds from which the heterocyclic nuclei, canbe derived include the azoles, oxazoles, selenazoles, triazoles (e.g., 1,2,4-triazoles, especially those containing an amino substituent in addition to the mercapto function), diazoles (e.g., imidazoles, benzimidazoles, imidazolines), pyrimidines, 1,2,4-triazines, s-triazines, monoazoles (e.g., benzoxazoles, benzothiazoles), azaindenes (e.g., tetrazaindenes) and the-like.
• N C-SX where Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6, preferably 5, atoms in a heterocyclic ring.
• SX is a mercapto function.
• the mercapto function or group can be in the free (SH) form or in the salt (SX) form.
• X is a cation, for example, hydrogen, an alkali metal such as sodium or potassium, ammonium or an organic amine residue of such amines as triethyl amine, triethanol amine, morpholine and the like.
• any of the heterocyclic compounds which contain at least one nitrogen atom and a mercapto function, as describedherein, willact as development foginhibitors in the practice of this invention.
• particularly good results are obtained with the mercapto azoles, especially the S-mercapto tetrazolesS-mercapto tetrazoles which can be employed in the practice of this invention include those having the formula: 1
• R is an aliphatic or aromatic radical containing up to 30 carbon atoms and 8X is as defined hereinbefore.
• R can be hydrocarbon or non-hydrocarbon and includes alkyl or aryl radicals which can contain atoms or groups other than carbon and hydrogen.
• Suitable atoms or groups which can be present in R together with carbon and hydrogen include, for example, alkoxy, phenoxy, halogen, cyano, nitro, amino, substituted amino, sulfo, sulfamyl, substituted'sulfamyl, sulfonylphenyl, sulfonylalkyl, fluosulfonyl, sulfonamidophenyl,”sul'fonamidoalkyl, carboxy, carboxylate, carbamyl, carbamylphenyl, carba'mylalkyl, carbonylalkyl, carbonylphenyl andsimilar groups.
• R is a hydrocarbyl radical containing up to 22 carbon atoms and SX is as defined hereinbefore.
• Suitable R groups include, for example, alkyl, aryl, alkaryl, aralkyl or alkaralkyl radicals, the preferred R groups being alkyl radicals containing 1-8-carbonatoms.
• the NHCOR' group on the 'phenyl ring can bein the ortho, meta or para -position.Such compounds can be prepared by the reaction of the l-(aminophenyl)-5-mercaptotetrazole hydrochloridewith an acid chloride having the formula R'COCl where R'has the above indicated meaning.
• the 1-(a minophenyl)-5-mercaptotetrazole is prepared'by reactionof an aminoacetanilide (ortho-, meta-, or,.para-),'. with thiophosgene to result in the formation of the corresponding acetamidophenyl i'sothiocyanate which is then reacted with an amide to form the mercaptotetrazole ring.
• This product is then hydrolyzed with concentrated hydrochloric acid to form the 1-(aminophenyl)-5-mercaptotetrazole hydrochloride.
• Acid chlorides which can be employed in the reaction with the mercaptotetrazole hydrochloride include the chlorides of the following acids: acetic, aceto-acetic, difluoroacetic, propionic, Valerie, iso-valeric, caproic, caprylic, undecanoic, stearic, benzoic, o-acetoxybenzoic, anthranilic, 3-amino-6-nitro-benzoic, p-tolyl acetic, 2,4- dinitrophenyl-acetic, methyl-sulfonic, o-toluene sulfonic, benzene sulfonic, p-bromobenzene sulfonic and o-formylbenzene sulfonic acid.
• heterocyclic nitrogen compounds which can be employed in the practice of this invention are, for example,
• the antifoggants employed in the practice of this invention are adsorbed to the fogged internal latent image silver halide grains. This can be accomplished by adding the antifoggant to the internal latent image emulsion prior to coating the emulsion.
• the antifoggants can be added to the emulsion in aqueous solution or in any convenient solvent not injurious to the emulsion, such as lower aliphatic alcohols, acetone, and the'like.
• the antifoggants are adsorbed to the fogged internal latent image silver halide grains and these grains can be blended with the surface latent image silver halide grains or coated in a separte layer. If, as preferred, the internal latent image emulsion and the surface latent image emulsions are coated in separate adjacent layers the antifoggants can simply be added to the internal image emulsion layer. The antifoggants cannot be added to blends of the internal image emulsions and surface image emulsions since this results in desensitization of the surface image emulsion. In general, the antifoggants are used in the fogged internal emulsion silver halide grains in concentrations of about 50 mg. to about grams, preferably about 100 mg. to about 2 grams per mole of silver halide.
• the surface image emulsions of our invention can be chemically sensitized by any of the accepted procedures.
• the emulsions can be digested with naturally active gelatin, or sulfur, selenium or tellurium compounds can be added such as those described in Sheppard U.S. Patent 1,574,944, issued Mar. 2, 1926, and Sheppard et al. U.S. Patent 1,623,499, issued Apr. 5, 1927 and Sheppard and Brigham U.S. Patent 2,410,689, issued Nov. 5, 1946.
• the surface image emulsions can also be treated with salts of the noble metals such as ruthenium, rhodium, palladium, iridium and platinum.
• Representative compounds are ammonium chloropalladate, potassium chloroplatinate and sodium chloropalladite, which are used for sensitizing in amounts below that which produces any substantial fog inhibition, as described in Smith and Trivelli U.S. Patent 2,448,060, issued Aug. 31, 1948, and as antifoggants in higher amounts, as described in Trivelli and Smith U.S. Patents 2,566,245, issued Aug. 28, 1951 and 2,566,263, issued Aug. 28, 1951.
• the surface image emulsions can also be chemically sensitized with gold salts as described in Waller et al. U.S. Patent 2,399,083 issued Apr. 23, 1946, or stabilized with gold salts as described in Damschroder U.S. Patent 2,597,856 issued May 27, 1952 and Yutzy and Leermakers U.S. Patent 2,597,915, issued May 27, 1952.
• Suitable compounds are potassium chloroaurite, aurite, potassium aurithiocyanate, potassium chloroaurate, auric trichloride and 2-aurosulfobenzo-thiazole methochloride.
• the surface image emulsions can also be chemically sensitized with reducing agents such as stannous salts (Carroll U.S. Patent 2,487,850, issued Nov. 15, 1949), polyamines such as diethylene triamine (Lowe and Jones U.S. Patent 2,518,698, issued Aug. 15, 1950), polyarnines, such as spermine (Lowe and Allen U.S. Patent 2,521,925, issued Sept. 12, 1950) or bis(;8-aminoethyl) sulfide and its water-soluble salts (Lowe and Jones U.S. Patent 2,521,926, issued Sept. 12, 1950).
• reducing agents such as stannous salts (Carroll U.S. Patent 2,487,850, issued Nov. 15, 1949), polyamines such as diethylene triamine (Lowe and Jones U.S. Patent 2,518,698, issued Aug. 15, 1950), polyarnines, such as spermine (Lowe and Allen U.S. Patent 2,521,925, issued Sept. 12, 1950) or bis(
• the photographic silver halide emulsion employed in the practice of this invention can be very highly sensitized and still exhibit very low fog upon development.
• the surface latent image emulsion can also contain silver halide emulsion sensitizers other than those described above which will substantially increase the speed of the emulsion.
• Suitable examples of such sensitizers include the alkylene oxide polymer sensitizers.
• the alkylene oxides from which the polymers are derived contain from 2 to 4 carbon atoms, e.g., ethylene oxide, propylene oxide and butylene oxide. The preparation of polymers from these compounds is described in Ellis, The Chemistry of Synthetic Resins (1935), pages 990 to 994.
• alkylene glycols These compounds are also referred to as polyalkylene glycols and their use as sensitizers for silver halide emulsions is described in U.S. Patents 2,423,549 and 2,441,389.
• Other alkylene oxide polymers which can be used to sensitize the photographic silver halide emulsions are prepared by condensing an organic compound containing an active hydrogen atom with an alkylene oxide polymer, .or by condensing the active hydrogen compound with the alkylene oxide during the polymerization of the latter material.
• alkylene oxide polymers can be used to sensitize the emulsions, e.g., condensation products of alkylene oxide with organic compounds containing an active hydrogen atom.
• active hydrogen organic compounds i.e., compounds in which a hydrogen atom can be replaced by reaction of the compound with metallic sodium, methylmagnesium iodide, etc.
• active hydrogen organic compounds include alcohols, amines, mercaptans, acids, amides, hydrocarbons such as acetylene, and compounds having the active hydrogen in a methylene group such as dibenzoylmethane.
• condensation products of alkylene oxide with glycols such as those having from 8 to 18 carbon atoms as described in U.S.
• Patent 2,240,472 and British Patent 443,559 as well as condensation products of alkylene oxides with aliphatic alcohols, condensation products of alkylene oxides with aliphatic acids, e.g., lauric acid and glycine, condensation products of alkylene oxides with aliphatic amines or amides, e.g., glycine and lauryl amide, and condensation products of alkylene oxides with phenols, e.g., phenol.
• the preparation of these condensation products is described in U.S. Patent 1,970,578. Condensation products of alkylene oxides with hexitol ring dehydration products as described in U.S. Patent 2,400,532 can also be employed.
• alkylene oxide polymers examples include polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foam, polystyrene, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene foams, polystyrene
• the polymers are condensation products of ethylene oxide with long chain compounds having a chain length of 12 or more carbon atoms or ethylene oxide polymers and have a molecular weight of 1500 to 4000 or more.
• alkylene oxide polymer sensitizers are generally employed in concentrations in the range of about .05 to about 5 grams, preferably .1 to about 2 grams per mole of silver halide.
• the surface latent image emulsions can also contain silver halide emulsion sensitizers containing at least one onium salt group.
• Such sensitizers generally contain one or more onium salt groups which are quaternary ammonium, quaternary phosphonium and/ or ternary sulfonium salt groups.
• the polyonium salts contain an .onium salt group, selected from the group consisting of quaternary ammonium, quaternary phosphonium and ternary sulfonium salt groups, linked through the onium atom by at least one bivalent organic radical to the onium group of another onium salt group selected from the group consisting of quaternary ammonium, quternary phosphonium and ternary sulfonium salt groups.
• onium salts examples include sulfonium lauryl triethyl ammonium perchlorate, nonyl dimethyl sulfonium-p-toluene sulfo nate, n-decyl triethyl phosphonium-p-toluene sulfonate, ethylene bis oxy methyl triethyl phosphonium chloride, ethylene bis oxy methyl-u-picolynium perchlorate, tetramethylene bis oxy methyl trimethyl phosphonium bromide, and the like.
• Suitable quaternary ammonium, quaternary phosphonium and ternary sulfonium salts are described in Carroll et al.
• the surface image emulsions can be spectrally sensitized, such as with cyanine or merocyanine dyes, if desired, and can contain antifoggants and stabilizers such as polyhydroxy benzenes, organic azoles, azaindenes, saccharides, metal salts such as cadmium, lead, mercury, gold or other noble metal salts.
• antifoggants and stabilizers such as polyhydroxy benzenes, organic azoles, azaindenes, saccharides, metal salts such as cadmium, lead, mercury, gold or other noble metal salts.
• gelatin In the preparation of the silver halide dispersions employed for preparing silver halide emulsions, there can be employed as the dispersing agent for the silver halide in its preparation, gelatin or some other colloidal material such as colloidal albumin, a cellulose derivative or a synthetic resin, for example, a polyvinyl compound, although gelatin is preferred.
• the photographic silver halide emulsion layers and other layers present in photographic elements made according to this invention can be hardened with any suitable hardener such as an aldehyde hardener, aziridine hardener, hardeners which are derivatives of dioxane, oxy- 9. polysaccharides such as oxystarch or oxy plant gums and other types of hardeners for gelatin and hydropholic colloids.
• any suitable hardener such as an aldehyde hardener, aziridine hardener, hardeners which are derivatives of dioxane, oxy- 9. polysaccharides such as oxystarch or oxy plant gums and other types of hardeners for gelatin and hydropholic colloids.
• the photographic silver halide emulsions can contain the sensitizing dyes, antifoggants and other ingredients used in emulsions of this type, as described in Luckey and Hoppe US. Patents 2,996,382, issued Aug 15, 1961 and 3,178,282, issued Apr. 13, 1965, and can be used in the various color and black-and-white systems described in those US. Patents.
• Typical supports include those generally employed for photographic elements, as exemplified by cellulose nitrate film, cellulose acetate film, polyvinyl acetal film, polystyrene film, polyethylene terephthalate film and related films of resinous materials as well as glass, paper, preferably paper coated with a polyolefin, e.g., polyethylene or ethylene butene copolymer.
• silver halide solvents which can be used in the developers comprise not only thiosulfate and sodium sulfite, but also water-soluble thiocyanates and water-soluble quaternary ammonium compounds, such as those illustrated in Welliver et al. US. Patent 2,648,604, issued Aug. 11, 1953.
• iodide ion can give unique effects.
• potassium iodide can be added to developers of the type described herein to enhance their effects, particularly in processing surface image emulsions having a low iodide content.
• the photographic silver halide emulsions of this invention exhibit very low fog upon development.
• a fogged internal image gelatino silver chlorobromide emulsion prepared as described in Example 4 of Luckey et al. US. Patent 2,996,382, issued Aug. 15, 1961, is mixed or blended with a high speed sulfur-gold sensitized gelatino bromoiodide emulsion having high surface sensitivity and low internal sensitivity.
• the sulfur and gold sensitized gelatino silver bromoiodide emulsion having high surface sensitivity and low internal sensitivity is of the type described in Example 1 of Luckey et al. US. Patent 2,996,382, issued Aug. 15, 1961.
• the surface image emulsion is coated on a conventional film support alone or in combination with the fogged internal image emulsion.
• An onium salt sensitizer and a mercapto azole are incorporated into certain of the coatings and omitted from others as shown in Table I which follows.
• the onium salt sensitizer employed is tetra-decamethylene-bis-(pyridinium perchlorate) and the mercapto azole is l-(3-capramido)-phenyl-5-mercaptotetrazole, the latter being added to the fogged internal image emulsion in a methanol solution.
• heterocyclic compounds described herein are effective anti foggants for the photographic emulsions comprising fogged internal image silver halide grains and unfogged surface latent image silver halide grains.
• the nitrogen compound is adsorbed to the fogged internal latent image silver halide grains and cannot be added to the surface latent image emulsion.
• the above procedure is repeated using a concentration of 4-16 mg. of the mercapto azole per mole of silver halide in the surface latent image emulsion. There is obtained a loss in sensitivity of up to 20%. Furthermore, when this procedure is repeated with a concentration of 0.5 gramof the mercapto azole/rnole silver halide in the surface latent image emulsion there is aspeed loss of 99%.
• Example 2 A series of coatings is prepared as described-in Example 1. The coatings are as follows:
• Example 3 As previously indicated, the photographic silver halide emulsions described herein can be sensitized with alkylene oxide polymers and still exhibit low fog upon development. To illustrate, the onium salt in Example 1 is replaced with the condensation product of oleyl alcohol with approximately 25 moles of ethylene oxide (polyethylene glycol oleyl ether).
• the coatings containing the mercapto heterocyclic nitrogen compounds in combination with the alkylene oxide polymer sensitizer exhibit lower fog for a given speed than the corresponding coatings containing the alkylene oxide polymer sensitizers alone.
• Suitable alkylene oxide 12 polymer sensitizers which can be used include the following polymers; the names of which are followed by a number indicating the average molecular weight of the polyethylene oxidechain:
• Alkylene oxide polymer sensitizers of this type are disclosed in Piper U.S. Patent 3,017,271, issued Jan. 16, 1962, Lundsted U.S. Patents 2,674,619, issued Apr. 6, 1954 and 3,022,335, issued Feb.'20, 1962.
• Example 4 Mercapto compounds which do not contain at least one heterocyclic ring do not give the desired results when used with the photographic silver halide emulsions described herein.
• a series of coatings is prepared as described in Example 2 except that the following mercapto compounds are employed:
• Example 5 The heterocyclic nitrogen compounds used in this invention must contain at least one mercapto group. To illustrate, a series of coatings is prepared as described in Example 2 using the following heterocyclic compounds which do not contain a mercapto group:
• Example 1 (1) Benzotriazole (2) 5-phenyl tetrazole (3) Z-methyl benzothiazole (4) 4-hydroxy-6-methyl-l,3,3a,7-tetrazaindene (5) S-aminoJ-hydroxy-1,2,3,4,6-pentazaindene (6) 2,5-dimeth'yl-7-hydroxy-1,4,7a-triazaindene
• the coatings are exposed and processed as described in Example 1.
• the fog values obtained are 50 to over 200% greater at a given speed level than are the corresponding coatings containing the heterocyclic nitrogen compounds described herein.
• emulsion blends or coatings described herein can be used in the same manner as those described in U.S. Patents 2,996,3 S2 and 3,178,282 and they will exhibit improved resistance to fog upon development.
• these emulsion blends or coatings can be used for recording and measuring very small amounts or dosages of gamma rays, such as might be encountered in dealing with the development of synthetic radio-isotopes.
• a photographic silver halide emulsion comprising fogged internal, latent image silver halide grains, un-
• a development fog inhibitor which is a heterocyclic nitrogen compound having the formula:
• a photographic silver halide emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a S-mercapto-tetrazole.
• a photographic sulfur-sensitized silver halide emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a heterocyclic nitrogen compound having the formula:
• I Z ha el-8X wher Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in a heterocyclic ring and SX is a mercapto function in which X is a cation.
• a photographic sulfur-sensitized silver halide emulsion additionally sensitized with a photographic silver halide emulsion sensitizer containing at least one onium salt group, said emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a heterocyclic, nitrogen compound having the formula:
• a photographic sulfur-sensitized silver halide emulsion additionally sensitized with a photographic silver halide emulsion sensitizer containing at least one onium salt group, said emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a S-mercapto tetrazole.
• a photographic sulfur-sensitized silver halide emulsion additionally sensitized with an alkylene oxide polymer sensitizer, said emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a heterocyclic nitrogen compound having the formula:
• Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in a heterocyclic ring and SX is a mercapto function in which X is a cation.
• a photographic sulfur-sensitized silver halide emulsion additionally sensitized with an alkylene oxide polymer sensitizer, said emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a S-mercapto tetrazole.
• a sulfur-sensitized photographic gelatino silver halide emulsion additionally sensitized with a photographic silver halide sensitizer containing at least one onium salt group, said emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a 1-(3-capramido)- phenyl-Smercapto-tetrazole.
• a sulfur-sensitized photographic gelatino silver halide emulsion additionally sensitized with an alkylene oxide polymer sensitizer, said emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a 1-( 3-capramido -phenyl-5-mercapto-tetrazole.
• a photographic element comprising a support, fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development fog inhibitor which is a heterocyclic, nitrogen compound having the formula:
• I 1 1 b-sx where Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in a heterocyclic ring and SX is a mercapto function in which X is a cation.
• a photographic element comprising a support, a first discrete silver halide emulsion layer of fogged internal latent image silver halide grains and, in close proximity to said first discrete silver halide emulsion layer, a second discrete silver halide emulsion layer of unfogged surface latent image silver halide grains; adsorbed to said fogged grains, a development fog inhibitor which is a heterocyclic nitrogen compound having the formula:
• Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5- to 6 atoms in a heterocyclic ring and SX is a mercapto function in which X is a cation.
• a photographic element comprising a support, a first discrete silver halide emulsion layer of fogged internal latent image silver halide grains and, in close proximity to said first discrete silver halide emulsion layer, a second discrete silver halide emulsion layer of unfogged surface latent image silver halide grains; adsorbed to said fogged grains, a development fog inhibitor which is a heterocyclic nitrogen compound having the formula:
• I 1' ( ]-SX
• Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in a heterocyclic ring
• SX is a mercapto function in which X is a cation.
• a photographic element comprising a support, a first discrete silver halide emulsion layer of fogged internal latent image silver halide grains and, in close proximity to said first discrete silver halide emulsion layer, a second discrete sulfur sensitized silver halide emulsion layer of unfogged surface latent image silver halide grains additionally sensitized with a photographic silver halide emulsion sensitizer containing at least one onium salt group; adsorbed to said fogged grains, a development fog inhibitor which is a heterocyclic nitrogen compound having the formula:
• 1 (
• Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5 to 6 atoms in a heterocyclic ring and SX is a mercapto function in which X is a cation.
• a photographic element comprising" a support, a first discrete silver halide emulsion l'ayerof fogged internal latent image silver halide grains and, in close proximity to said first discrete" silver halide emulsion layer, a second discrete sulfur-sensitized silver halide emulsion layer of unfogged surface latent image silver lialide grains-additionally sensitized'with an alkylerie oxide polymer sensitizer; adsorbed to said fogged grainsfa development fog inhibitor which is a heterocyclic; nitrogen compound having the formula; v v 4 V,'Z,- ⁇
• I-'I o-sX
• Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus containing from 5*to-6 atoms in a heterocyclic ring and SX is a mercapto function in whichXis'a cation.
• a photographic element comprising a support, a sulfur-sensitized photographic silver halide emulsion additionally sensitized with a photographic silver halide emulsion sensitizer containing at least one onium salt group, said emulsion comprising fogged internal latent image silver halide grains, unfogged surface latent image silver halide grains and; adsorbed to said fog'ged grains'f-a development fog'inhib'itor which is a S-mercapto tetrazole.
• lttf'A photographic element comprising" a support, a sulfur-sensitized photographic silver halide emulsion additionally sensitized with an alkylene oxide polymer sensitizer, said emulsion comprising fogged internal latent image silver halide grains, untogged surface latent image silver halide grains and, adsorbed to said fogged grains, a development foginhibitor which is a S-mercapto tetrazole. 19.
• a photographic element comprising a support,-a sulfur sensitized photographic silver.
• halide emulsion additionally sensitized withan alkylene oxide polymer serisitizer, said emulsion comprising fogged internal laten't image silver halide grains, unfogged surface latent image silver halide grains and, adsorbed to said fogged grains; a development fog inhibitor which is a l-phenyl-S-mrcapto tetrazole.

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Cited By (29)

• 1965
  • 1965-05-24 US US458400A patent/US3397987A/en not_active Expired - Lifetime
• 1966
  • 1966-05-19 GB GB22353/66A patent/GB1138758A/en not_active Expired
  • 1966-05-20 BE BE681359D patent/BE681359A/xx unknown

Non-Patent Citations (1)

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