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
  • G03C1/485—Direct positive emulsions
  • G03C1/48515—Direct positive emulsions prefogged

Definitions

• This invention relates to direct-positive photographic silver halide emulsions.
• this invention relates to the addition of gold complexes as an addendum after the fogging of a direct-positive silver halide emulsion to improve the photographic properties of said emulsion.
• this invention relates to directpositi-ve halide emulsions which have improved maximum image density upon incubation and aging.
• the photographic properties of a fogged direct-positive silver halide emulsion can be improved by the addition of gold complexes to the gelatin used to make up the coating emulsion or to the fully sensitized, fogged, direct-positive emulsion.
• the improvements are especially noticeable in direct-positive silver halide emulsions which have been reduction and gold fogged.
• the photographic speed of producing the positive image and the shape of the sensitometric curve is substantially the same as a fresh control emulsion without the gold addendum:
• the gold complex is a monovalent gold complex, i.e. where the gold is in the monovalent state.
• the gold complex is an alkali metal or ammonium aurous dithiosulfate.
• the gold complex addenda is added to a direct-positive emulsion which has been reduction and gold fogged.
• this invention relates to a process of making a photographic element comprising (1) fogging the silver halide emulsion, (2) adding a gold salt complex to the emulsion and (3) coating said emulsion on a support.
• the gold complex is added to a fogged, direct-positive silver halide emulsion wherein the grains of said silver halide emulsion contain sites for the formation of phottlytic silver.
• the gold salt complexes are added to reduction and gold fogged silver halide emulsions to provide very good improvements in photographic properties, especially when an alkali metal or ammonium aurous dithiosulfate is added to the emulsion.
• the gold complexes of this invention can be incorporated into the emulsion at any time after the fogging steps. Preferably, they are added to the fogged, direct-positive emulsion after all ripening, sensitizing and digestion steps are completed in a manner which will substantially avoid immediate reaction with the silver halide. Suitable concentrations of the gold complex are generally from about 1 mg. to about 200 mg. per mole of silver halide and preferably from about 20 to about 60 mg. per mole of silver halide.
• Typical useful gold complexes include alkali-metal aurous dithiosulfates, alkali-metal auric halide complexes, aurous sulfide, thiourea-auric halide complexes, auric chloride 3 ethyl-5-[ (3-ethyl-2(3H)-benzoxazolylidene) ethylidene]-rhodanine addition products, alkali-metal auric thiocyanates, 1',1'-diethyl-2,2'-cyanine auric tetrachloride and the like.
• the gold complex is an alkali-metal aurous dithiosulfate.
• the direct-positive silver halide compositions useful in this invention can be generally classified as blue-sensitivedirect-positive silver halide compositions. It is understood that blue-sensitive means that the direct-positive compositions will provide a reversal image when exposed with light in the 350- to 500-millimicron range of the electromagnetic spectrum and then developed.
• the silver halide compositions can also be spectrally sensitized so as to form reversal images when exposed in other regions of the spectrum such as in the green and red regions. However, they all have the property of being capable of forming a reversal image when exposed with light in the blue region of the visible spectrum.
• Typical direct-positive silver halide compositions useful in the present invention include:
• Emulsions containing fogged silver halide grains which have internal centers for the deposition of photolytic silver such as those generally disclosed in Berriman, U.S. Pat. 3,367,778 issued Feb. 6, 1968, including emulsions comprising grains which have centers which promote the deposition of silver which are either sufiiciently small or sufficiently buried within the crystal as to be not accessible to initiate surface development to a visible image.
• Silver halide grains of this latter type can be provided by '(a) using very low concentrations of sensitizing agent throughout the precipitation, (b) adding the sensitizing agent to the precipitation medium during the initial part of the precipitation, (c) reducing part of the silver nitrate used in the initial portion of the precipitation, etc.
• Emulsions which contain silver halide grains which are uniformly fogged to specific levels and contain electron-accepting compounds adjacent the grains, as described in lllingsworth, U.S. Ser. No. 619,948 filed Mar. 2, 1967, now U.S. Pat. 3,501,305 issued Mar. 17, 1970.
• Emulsions comprising fogged regular grains which contain an electron-accepting compound or desensitizer adjacent the grains, as described in lllingsworth, U.S. Ser. No. 619,909 filed Mar. 2, 1967, now U.S. Pat. 3,501,306 issued Mar. 17, 1970.
• Emulsions comprising monodispersed grains which have been reduction and gold fogged, as described in lllingsworth, U.S. Ser. No. 619,936 filed Mar. 2, 1967, now U.S. 'Pat. 3,501,307 issued Mar. 17, 1970.
• the silver halides employed in the preparation of the photographic compositions described herein include any of the photographic silver halides as exemplified by silver bromide, silver chloride, silver chlorobromide, silver bromoiodide, silver chlorobromide, and the like.
• Silver halide grains having a mean grain diameter i.e., an average grain size in the range of about .01 to about 2 microns, preferably about .02 to about 1 micron, give particularly good results in reversal systems.
• the silver halide grains can be any suitable shape such as cubic or octahedral, but they are preferably cubic, and more preferably cubic-regular.
• the preferred photographic silver halide emulsions comprise at least 50 mole percent bromide, the most preferred emulsions being silver bromoiodide emulsions, particularly those containing less than about 10 mole percent iodide.
• the photographic silver halides can be coated at silver coverages in the range of about 50 to about 500 milligrams of silver per square foot of support.
• the direct-positive photographic silver halide emulsions of this'invention contain silver halide grains which are fogged. Fogging can be effected by chemically or physically treating the photographic silver halides by methods previously described in the prior art. Such fogging can be accomplished by various techniques such as chemical sensitization to fog, particularly good results being obtained with techniques of the type described by Antoine Hautot and Henri Saubenier in Science et Industries Photographiques vol. XXVIII, January 1957, pages 57- 65..
• the silver halide grains can be fogged with the highintensity light, reduction fogged with a reducing agent such as thiourea dioxide or stannous chloride or fogged with gold or noble metal compounds.
• Combinations of reduction fogging agents with gold compounds or compounds of another metal more electropositive than silver, e.g., rhodium, platinum or iridium, can be used in fogging the silver halide grains.
• the fogged silver halide grains in the direct-positive photographic emulsions of this invention give a density of at least 0.5 when developed without exposure for minutes at 68 F. in Kodak DK-50 developer when a direct-positive emulsion containing such grains is coated at a coverage of 50 to about 5000 mg. of silver per square foot of support.
• the direct-positive photographic emulsions of this invention can comprise reduction and gold fogged silver halide grains, i.e., silver halide grains which are fogged with a combination of a reduction fogging agent and a gold fogging agent.
• reduction and gold fogging agents in such a combination give unique fogged silver halide grains which are characterized by a rapid loss of fog upon chemical bleaching. It is known that 1 equivalent weight of a reducing agent will reduce 1 equivalent weight of silver halide to silver. To obtain the fogged silver halide grains which are characterized by a rapid loss of fog upon bleaching, much less than 1 equivalent weight of reduction fogging agent is employed.
• reduction fogging agent per mole of silver halide
• about 0.0005 to about 0.06, preferably about 0.001 to about 0.03, milliequivalent of reduction fogging agent per mole of silver halide is employed in fogging the silver halide grains in the practice of this invention.
• concentrations of reduction fogging agent can result in a substantial loss in photographic speed.
• a preferred reduction fogging agent employed in combination with a gold fogging agent, or a compound of another metal more electropositive than silver is thiourea dioxide which is preferably employed in a concentration in the range of about 0.05 to about 3, most preferably about 0.1 to about 2 mg.
• Stannous chloride is another suitable reduction fogging agent which is used in practicing this invention and is preferably used in concentrations in the range of about 0.05 to about 3 mg. of stannouschloride per mole of silver halide.
• reduction and gold fogging agents in low concentration gives direct-positive photographic silver halide emulsions exhibiting outstanding photographic speed.
• polyamines such as spermine as disclosed in U.S.
• the gold fogging agents employed in practicing this invention can be any gold salt suitable for use in fogging photographic silver halide grains and includes the gold salts disclosed in U.S. Pats. 2,399,083 by Waller et al. issued Apr. 23, 1946, and 2,642,361 by Damschroder et al. issued June 16, 1953.
• Specific examples of gold fogging agents are potassium chloroaurite, potassium aurithio cyanate, potassium chloroaurate, auric trichloride, 2-aurosulfobenzothiazole metho chloride, and the like.
• the concentration of gold fogging agent employed in the practice of this invention is subject to variation, but is generally in the range of about 0.001 to about 0.01 millimole per mole of silver halide.
• Potassium chloroaurate is a preferred gold fogging agent and is often used at concentrations of less than about 5 mg. per mole of silver halide and preferably at concentrations in the range of about 0.5 to about 4 mg. per mole of silver halide.
• the direct-positive emulsion used in this invention contain electron-accepting compounds, often referred to as a desensitizers or electron traps, which are generally compounds having an anodic polarographic halfware potential and a cathodic polarographic potential which, when added together, give a positive sum.
• electron-accepting compounds often referred to as a desensitizers or electron traps, which are generally compounds having an anodic polarographic halfware potential and a cathodic polarographic potential which, when added together, give a positive sum.
• Typical useful electron-accepting compounds, along with methods of determining the polarographic potentials are disclosed in the above-mentioned applications on direct-positive emulsions, as well as in Illingsworth et al., U.S. Ser. No. 609,761 filed Jan. 17, 1967, now U.S. Pat. 3,- 501,310 issued Mar. 17, 1970.
• An especially useful class of electron acceptors which can be used in the directpositive photographic silver halide emulsions, and procasses of this invention are cyanine dyes such as the imidazo [4,5-b] quinoxaline dyes. Dyes of this class are described in Brooker and Van Lare, Belgian Pat. 660,253 issued Mar. 15, 1965. 'In these dyes, the imidazo[4,5-b] quinoxaline nucleus is attached, through the Z-carbon atom thereof, to the methine chain.
• the direct-positive emulsions of this invention also can contain compounds referred to as halogen-accepting or halogen-conducting compounds, especially if the halide of the emulsion is predominantly chloride.
• Useful compounds of this type are generally characterized by an anodic polarographic potential less than 0.85 and a cathodic polarographic potential which is more negative than 1.0.
• Highly preferred species of compounds of this type are merocyanine dyes having the above halfwave potentials.
• Typical compounds of this type, along with methods of determining the polarographic potential, are disclosed in the above-mentioned applications on direct-positive emulsions as well as in Wise, U.S. Ser. No. 615,360 filed Feb. 13, 1967, now U.S. Pat. 3,537,858 issued Nov. 3, 1970.
• the emulsions of this invention can also contain the hardeners, coating aids, surfactants, development modifiers, sensitizers, stabilizers, incorporated developer agents, binder vehicles and lubricants as disclosed in the art for direct-positive emulsions.
• the improved direct-positive emulsions of this invention Dyes which are used as electrons acceptors in emulsions can be processed by conventional photographic developof this type accelerate the density reduction as described mcnt processes, monobath processes, two-stage processes in Example 2. and the like as generally known in the art for blue-sensi- EXAMPLE 2 tive-direct-positive silver halide emulsions.
• Typical useful two-stage processes referred to above include those de- In thls example the emulslon 15 the Same as scribed in Bath Rapid Stabilization Processing, The ample 1 with a spectral-sensitizing dye added before the British Journal of Photography, July 21, 1967, pages 620- 3 2 3?2 z f k P fi f T 25; Broughton, U.S. Pat. 2,514,927; British Pat. 1,003,- P 8 dye 1s a v q -qg 436; and Barbier, US. Pat. 3,212,895 issued Oct. 19, 1965.
• EXAMPLE 1 Silver bTQmOiOdide gelatin m
• the emulsion and coating conditions are the same as in duction and gold fogged, 1s prepared as described in 'Berri- Example 2 With the exception that the man, US. 'Pat. 3,367,778, and used to illustrate the in- N [AMS 0 TH O vention.
• a water solution of gold complex, dd d h h f 3 2 d 2 h is a e to t e emu sion e ore a ding t e spectral-sensi- Naa [Au(s2o3)2] ZHZO tizing dye and make-up gelatin.
• Example 1 is the same as Example 1 except that tometer for 1 second to a 500 w. 3000 K. bulb modulated KAuCl -2H O is used in place of Na [Au(S O -2H O.
• EXAMPLE 6 Dyes I-VII are added with and without 20 mg. of the gold complex Na [Au(S O ),]-2H,O/Ag mole to portions of a reduction and gold fogged silver bromoiodide gelatin emulsion of the type described in Berriman, US. Pat. 3,367,778.
• the emulsion samples are held for 10 minutes at 40 C., coated on cellulose acetate film support at 100 mg. Ag/ftfi, chill-set and dried.
• the films are exposed on an Eastman 1B sensitometer to a 500 W. 3000 K. bulb modulated by a step wedge, developed 6 minutes in an Elon-hydroquinone developer, fixed, washed and dried.
• Norm-Dye I 1,3-dlallyl-6-ehloro-l-methyl-2-phenylimidazo[4,5-b]-quinoxa1ino-3-lndolocarbocyar1ine ptoluenesulionate.
• Dye II 1,1 dimethyl-2 2-diphenyl-3,3'-benz[g]indolocarhocyanine bromide.
• Dye IV 1,3-dlally1-1,3 ,3-t1'imethyl-6-nitroimidazo[4,5-b]-quinoxalinoindocarbo0yanine bromide.
• Dye V 2-[2-(1,B-diphenyl-Z-pyrrolyl) vinyll-l,3,3-trimethyl-fi-nitro-liH-indolium perchlorate.
• Dye VI 1,3,3-trimethyl-8,lO-diphenyl-SH-benz0[glimldaz0-[4,5-b]quinoxalinoindocarbocyapme iodide.
• Dye VII 1,3,3-trimethyl-6-nitro-1,3-diphenyllmidazo[4,5-b]quinoxallnoludocarboeyanine iodide.
• a direct-positive, fogged silver halide emulsion comprising at least about 1 mg. per mole of silver halide in said emulsion of a gold salt complex selected from the group consisting of alkali metal and ammonium aurous dithiosulfates, alkali metal auric halide complexes, thioureaauric halide complexes, auric chloride 3 ethyl--[(3-ethyl-2-(3H)-benzoxazolylidene) ethylidene1-rhodanine addition products, 1,1' diethyl- 2,2'-cyanine auric tetrachloride and alkali metal auric thiocyanates, said gold salt complex being added to said emulsion after fogging the emulsion.
• a gold salt complex selected from the group consisting of alkali metal and ammonium aurous dithiosulfates, alkali metal auric halide complexes, thiour
• An improved blue-sensitive-direct-positive silver halide emulsion comprising reduction and gold fogged silver halide grains and having internal sites for the deposition of photolytic silver and/or an electron-accepting compound adsorbed to the surface of said fogged grains, said electron-accepting compound having an anodic polarographic half-wave potential and a cathodic polarognaphic potential which, when added together, give a positive sum, the improvement comprising the addition of at least 1 mg.
• the gold salt complex is selected from the group consisting of alkali metal and ammonium aurous dithiosulfates, alkali metal auric halide complexes, thiourea-auric halide complexes, auric chloride 3 ethyl-5-[(3-ethyl-2 (3H)-benzoxazolylidene) ethylidene1-rhodanine addition products, l',1'-diethyl 2,2 cyanine auric tetrachloride and alkali metal auric thiocyanates.
• a process of making a fogged, direct-positive silver halide element comprising the steps of (1) reduction and gold fogging silver halide grains, (2) adding a gold salt complex selected from the group consisting of alkali metal and ammonium aurous dithiosulfates, alkali metal auric halide complexes, thiourea-auric halide complexes, auric chloride 3 ethyl-5-[(3-ethyl-2(3H)-benzoxazolylidene) ethylidene1-rhodanine addition products, l,1'-diethyl-2,2' cyanine auric tetrachloride and alkali metal auric thiocyanates as an addendum, in a concentration of about 1 mg. to about 200 mg. of said complex per mole of silver halide, to an emulsion comprising said fogged grains, and (3) coating the emulsion containing said gold salt complex on a support.
• a process of making a fogged, direct-positive photographic silver halide element comprising the steps of (1) reduction and gold fogging silver halide grains, (2) adding an ammonium or alkali metal aurous dithiosulfate as an addenum, in a concentration of about 20 to about 60 mg. per mole of silver halide to an emulsion comprising said fogged grains, and (3) coating the emulsion containing said ammonium or alkali metal aurous dithiosulfate on a support.
• a process of making a fogged, direct-positive, silver halide emulsion comprising the steps of (1) reduction and gold fogging silver halide grains, and (2) adding a gold salt complex selected from the group consisting of alkali metal and ammonium aurous dithiosulfates, alkali metal auric halide complexes, thiourea-auric halide complexes, auric chloride 3 ethyl-5-[(3-ethyl-2(3H)-benzoxazo1ylidene) ethylidene1-rhodanine addition products, 1',l-diethyl-2,2'-cyanine auric tetrachloride and alkali metal auric thiocyanates, as an addendum, in a concentration of about 1 mg. to about 200 mg. of said complex per mole of silver halide, to an emulsion comprising said fogged grams.
• a gold salt complex selected from the group consisting of alkali metal and
• a process of making a fogged, direct-positive, silver halide emulsion comprising the steps of (1) reduction and gold fogging silver halide grains and (2) adding an ammonium or alkali metal aurous dithiosulfate as an addendum, in a concentration of about 20 to about 60 mg. per mole of silver halide, to an emulsion comprising said fogged grains.
• a photographic element comprising a support having thereon a direct-positive, fogged silver halide emulsion
• the improvement comprising at least about 1 mg. per mole of silver halide in said emulsion of a gold salt complex selected from the group consisting of alkali metal and ammonium aurous dithiosulfates, alkali metal auric halide complexes, thiourea-auric halide complexes, auric chloride 3 ethyl-5-[(3-ethyl-2(3H)-benzoxazolylidene) ethylidene1-rhodanine addition products, 1',1'-diethyl-2, 2'-cyanine auric tetrachloride and alkali metal auric thiocyanates, said gold salt complex being added to said emulsion after fogging the emulsion.
• a gold salt complex selected from the group consisting of alkali metal and ammonium aurous dithiosul
• a photographic element comprising a support having thereon a direct-positive, fogged silver halide emulsion
• the improvement comprising about 20 mg. to about 60 mg. per mole of silver halide in said emulsion of an ammonium or alkali metal aurous dithiosulfate which is added to said emulsion after fogging the emulsion.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=21752187

Family Applications (1)

Country Status (10)

Cited By (6)

Family Cites Families (3)

• 1970
  • 1970-02-16 US US11837A patent/US3672903A/en not_active Expired - Lifetime
• 1971
  • 1971-01-11 CA CA102,330A patent/CA976023A/en not_active Expired
  • 1971-01-29 BR BR773/71A patent/BR7100773D0/pt unknown
  • 1971-02-13 JP JP46005988A patent/JPS5142488B1/ja active Pending
  • 1971-02-15 FR FR7104940A patent/FR2078584A5/fr not_active Expired
  • 1971-02-15 AU AU25448/71A patent/AU2544871A/en not_active Expired
  • 1971-02-15 CH CH215571A patent/CH527440A/fr not_active IP Right Cessation
  • 1971-02-15 DE DE2107119A patent/DE2107119C3/de not_active Expired
  • 1971-02-15 BE BE762988A patent/BE762988A/xx not_active IP Right Cessation
  • 1971-04-19 GB GB2102171A patent/GB1338433A/en not_active Expired

Also Published As

Similar Documents