US2860982A - Supersensitization of photographic silver halide emulsions - Google Patents

Supersensitization of photographic silver halide emulsions Download PDF

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US2860982A
US2860982A US586054A US58605456A US2860982A US 2860982 A US2860982 A US 2860982A US 586054 A US586054 A US 586054A US 58605456 A US58605456 A US 58605456A US 2860982 A US2860982 A US 2860982A
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emulsion
pyridine
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emulsions
silver
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Jean E Jones
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Eastman Kodak Co
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Eastman Kodak Co
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    • 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

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  • This invention relates to photographic #silver halide emulsions containing certain polymethine dyespand in supersensitizing combination therewith, pyridine bases.
  • the sensitization of va given emulsion by a given dye may lbe altered by varying the'conditions in the emulsion. For example, the sensitization may be increased by increasing the silver ion concentration Vor decreasing lthe hydrogen ion concentration (i.
  • -sensitization can be increased by bathing plates, coated with a spectrally sensitized emulsion, in water or in aqueous .solutions of ammonia.
  • Such a process of altering the sensitivity of a sensitized emulsion by increasing the silver Aion concentration and/or by Vdecreasing 'the hydrogen ⁇ ionr'concentration is commonly called -hypersensitization.
  • ⁇ Hypersensitized emulsions have generally poor ykeeping qualities.
  • polymethine dyes useful'in'practicing my invention can be represented by the following general formula:
  • R represents l an 'alkyl'.group, such as imethyl, ethyl, propyl, butyl, carbethoxymethyLbenzyl ,(phenylmethyl), etc. (e. g., an alkyl group containing from l to 4 carbon atoms)
  • Vn represents a positive integer of from l to 2
  • Q represents the non-metallic ⁇ atoms-necessary to complete a cyclohexene Aring
  • Z represents the non-metallic atoms necessary to complete al heterocyclic nucleus containing from 5 --to 6 atoms in the heterocyclic ring, such as those ⁇ selected from the group consisting of those of the benzothazole series ⁇ (e.
  • benzothiazole 4-chlorobenzothiazole, V5- chlorobenzothiazole, -chlorobenzothiazole, 7-chlorobenzothiazole, 4- methylbenzothiazole, 5methylbenzothiazole, y-methylbenzothiazole, 5-bromobenzothiazole, ebromobenzothiazole, 4-phenylbenzothiazole, ,Sfphenylbenzothiazole, y4- methoxybenzothiazole, 5-methoxybenzothiazole, ;6.methoxybenzothiazole, 5iodobenzothiazole, 6'.iodol:ienz'othia zone, 4-ethoxybenzothiazole, vS-ethoxybenz'othiazole, tetvrahydrobenzothiazole, 5,-dimethoxybenzothiazole, 25,6-
  • benzoxazole 5-chlorobenzoxazole, 5-methylbenzoxavzole, 5- phenylbenzoxazole, "-methylbenzoxazole, *i6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5-methoxybenzoxazole, 5ethoxybenzoxazole, 5-chlorobenzoxazole, 6- rnethoxybenzoxazole, v5-hydroxybenzoxazole, 6-hydroxy- .benzoxazole, etc.), those of the naphthoxazole series (e.
  • naphtho[1,2loxazole, naphtho[2,l]oxazole, etc. those of the benzoselenazole series (e. g., benzoselenazole, 5-chlorobenzoselenazolc, 5methoxybenzoselenazole, 5 hydroxybenzoselenazole, tetrahydrobenzoselenazole, etc.), those of the'naphthoselenazole series (e. g., naphtho[l,2]selenazole, naphtho[2,l]selenazole, etc.), lthose of the thiazoline series' (e.
  • thiazoline 4-methylthiazoline, etc.
  • those of the benzimidazole series e. g., 1,3-di; ethylbenzimidazole, l-ethyl-3-phenylbenzimidazole, etc.
  • the 3,3-dialkylindolenine series e. g., 3,3-dimethylindolenine, 3,3,5 trimethylindolenine, 3,3,7 trimethylindolenine, etc.
  • Especially useful polymethine dyes embraced by Formula I which can be used in my invention comprise the dyes represented by the following general formula:
  • R4 represents a hydrogen atom or a lower alkyl group, such as methyl, ethyl, etc.
  • Typical bases include pyridine, 1:-, 'and vfy-picoline, etc.
  • Polymethine dyes selected from those of Formula I which can be used in my invention comprise those represented by the following formulas:
  • My invention is particularly directed to the ordinarily employed gelatinosilver-halide emulsions.
  • my supersensitizing combinations can beemployed in silver halide emulsions in which the carrier is other than gelatin, e. g., a resinous substance or cellulosic material which has no deteriorating effect on thesilver halide.
  • My invention is primarily directed to the ordinarily employed gelatno-silver-halide developing-out emulsions, e. g., gelatino-silver-chloride, chlorobromide, -chloroiodide, chlorobromiodide, -bromide and bromiodide developing-out emulsions. While the results in the following examples were obtained using gelatino-silver-bromiodide emulsions, useful results have also been obtained using gelatino-silver-chlorobromide emulsions. Particularly improved sensitizing activity has been obtained in gelatino-silver-bromiodide emulsions of the developingout type. Emulsions which form the latent image mostly inside the silver halide grains, such as the emulsions set forth in U. S. Patent 2,456,956, dated December 2l, 1948, can also be employed in practicing my invention.
  • emulsions prepared in accordance with my invention can be coated in the usual manner on any suitable support, e. g., glass, cellulose nitrate lm, cellulose acetate lm, polyvinyl acetal resin film, glycol terephthalate film, polystyrene lm, paper, metal, etc.
  • suitable support e. g., glass, cellulose nitrate lm, cellulose acetate lm, polyvinyl acetal resin film, glycol terephthalate film, polystyrene lm, paper, metal, etc.
  • the polymethine sensitizing dyes of Formula I or la and pyridine bases of Formula II can be employed in various concentrations, depending upon the effects desired.
  • the sensitivity conferred upon an emulsion by a sensitizing dye does not increase proportionately to the concentration of the dye in the emulsion, but rather passes through an optimum as the concentration is increased.
  • the individual sensitizing dyes are advantageously employed at approximately their optimum concentration (i. e., the concentration at which the individual dyes give their greatest sensitivity).
  • the pyridine bases represented by Formula II above have little or no sensitizing action on the emulsions.
  • the optimum concentration of a sensitizing dye can be determined in amanner well known to those skilled in the art by measuring ⁇ the sensitivity of a series of test portions o f the same emulsion, each portion containing a different concentration of the sensitizing dye.
  • the optimum concentration of my supersensitizing combinations can, of course, be readily determined in the same manner, by measuring the sensitivity of a series of test portions of the same emulsion, each portion containing aditerent concentration of the sensitizing dye used in the combination. In determining the optimum concentration for" the supersensitizing combination, it is adtion.-l Thezconcentration. of the.
  • VE offsensitizingzdye and A ⁇ pyridinebase actuA combination is-determined.'. 5;. ally incorporated in the emu1sion ..will. vary somewhat 4 Ordinarily;.theoptimumorrneangoptiinunnconcentrafrom case to v case, according to lthe emulsion' employed, tionwof. ⁇ the@ dyes selected.;-from.;those; represented. byi particular sens itiz ingdyev and pyridine base.emp loyed,1 Formula AI oriIa vabove:which-:Izeruployfinpractising my and accordingto the ⁇ eiectdesired. The regiilation ⁇ and.
  • centrationsf-on.theaorderfofrom lOaOyto 5.0.,Ojgi1amsf.perr are to be -regarded only.as.illustratiyef
  • Clearlyfmy inmolaofsilverhalide in fthe.emulsione ⁇ vention is directed to any emulsion containing a com- ⁇ Generallysspeaking. the;.concentration-.of.thel dyeof l5- bination of the aforesaid ,sensitizing dyes.
  • the sensitizing dyes of Formula I Oria.. and a pyrldme base such aSthOSe renresentedby Forcan. be .dissolved in .arn appropriate solvent,- such vas ace- 25' Hilliad abOVe- N0 data 0n the ,COalDg Contalllillg the tone,.meth'ano1, etc., andzthese solutions added to the pyridine.
  • the ySUPPGITS aUdVeXPOSedIl invention are advantageously incorporated in the finished, the S1121 'manner 111 a Speetl'qgrapi? aan@ a.
  • SCHStOmeief washedemulsions and shouldA beuniformlyidistributed (Type Ib), through e flite.
  • 3S Jdel'flfedln the following throughout the emulsions. The following procedure is table..
  • the desired amounts of the stock solup N.mg/1151121111inophenol. ⁇ sulfate 2.0 tion of one or more of these sensitizing dyes is slowly Hydroquinone 8.0 added, while'stirring the. emulsion.4 Stir'ring is continued 45 Sodiumnsul' (mhy'dfws) r l 90 0 until thedye '(or dyes) is thoroughlyincorporated 1n the Sodium CarbonateV monohydrat 52,5 emulsion: Then, the Adesired amount ofthe pyridine base Potassium.
  • bromide A 5 0 is slowly' added to the-emulsion, while stirring.; If'de- Waterfomaka one liter. sired, the pyridine ,base can be addedv prior to the solu- L tion of sensitizing dye (or. dyes), or amixture. Ofthese 50 Wratten No.
  • IZlter transmits substantially no light two ingredients can be added" ina single operation; of Wavelength shonethan ab0uff-495 111111 andfwfatten
  • stirring NO- 215 ltef transmts 'Substantlally 110 hht 0f Wave is continued until all ingredientsl have been uniformly lellgihshoftef than-ab0ut-580 m11- dispersed throughout the emulsions.
  • the supersensitized The. i1ierS.-11Sed..1 i1 helexarnples. below were selected ⁇ emulsion can then be coated out on a suitable support, 55 SOthat they. ranSmitted. light..lrrtheegioninwhich the. such as glass, ce1lulose. nitrate lm, vcellulose acetate. film, sensitizing. dyes.had,thei r ⁇ maximum sensitivity.
  • the accompanying drawing illustrates the supersensitizing effect obtained with three of my new combinations of polymethine dyes and the pyridine bases in gelatinosilver-bromiodide emulsions.
  • ing is a diagrammatic reproduction of two spectrograms.
  • the sensitivity of the emulsion containing only the polymethine dye of Formulas I or Ia is represented by the solid curve.
  • the sensitivity of the emulsion containing both the polymethine dye of'Formulas I or Ia and the pyridine base of Formula II is represented by the curve consisting of short dashes. No curve showing the sensitivity of the emulsion containing the pyridine base of Formula Il is shown, since these compounds have no measurable effect on the emulsions employed.
  • curve A represents the sensitivity of an ordinary gelatino-silver-bromiodide emulsion sensitized with 2[ (3-dicyanomethylene-1cyclohexen1yl) methylenelf3-methylbenzothiazoline
  • curve B represents the sensitivity of the same emulsion sensitized with 2-[(3 dcyanomethylene- 1cyc1ohexen l-yl -methylenel -3 -methylbenzothiazoline and pyridine.
  • I ⁇ he sensitometric measurements for these .emulsions are given in Example 2 of the above table.
  • curve C represents the sensitivity of. an ordinary gelatino-silver-bromiodide emulsion sensitized with 2- (3-dicyanomethylene-l-cyclohexen-l-yl methylene]-S-methylbenzoxazoline
  • curve D represents the sensitivity of the same emulsion sensitized with 2-[.(3 dicyanomethylene-l-cyclohexen-l-yl)methylene]3meth ylbenzoxazolinc ⁇ and pyridine.
  • the sensitometric measurements for these emulsions are given in Example 7 of the above table.
  • curve E represents the sensitivity of an ordinary gelatino-silver-bromiodide emulsion sensitized with 2- l (6-carbethoxy-3-dicyanomethylene-1-cyclohexen- 1-yl)methylene]-3-methylbenzoxazoline
  • curve F Each figure of the draw-V Cir represents the sensitivity of the same emulsion sensitized g M with 2- 6-carbethoxy-3-dicyanomethylene-1 -cyclohexeni 1 yl)methylene] 3 methylbenzoxazoline and pyridine.4 fj.,
  • Photographic silver halide emulsions such as those n listed above, containing the supersensitizing combinations of my invention can also contain such addenda as chemical sensitizers, e. g., sulfur sensitizers (e. g., allyl thiocarbamide, thiourea, allylisothiocyanate, cystine, etc.), various gold compounds (e. g., potassium chloroaurate, auric trichloride, etc.) (see U. S. Patents 2,540,085;
  • chemical sensitizers e. g., sulfur sensitizers (e. g., allyl thiocarbamide, thiourea, allylisothiocyanate, cystine, etc.)
  • gold compounds e. g., potassium chloroaurate, auric trichloride, etc.
  • anti-foggants such as ammonium chloroplatinate (U. S. 2,566,245), ammonumchloroplatinite (U. S. 2,566,263), benzotriazole, nitrobenzimidazole, 5- nitroindazole, benzidinc, mercaptans, etc. (see Mees- The Theory of the Photographic Process, Macmillan Pub., page 460), or mixtures thereof; hardeners, such as i formaldehyde (U. S.
  • polymethine dyes represented by Formula I above which are useful in practicing my invention, can be prepared according to the method described in the copending application Serial No. 585,946, led on even date herewith in the names of L. G. S. Brooker and D. W. Heseltine.
  • lower alkyl as used in the foregoing specication and the following claims means an alkyl group containing from 1 to 2 carbon atoms.
  • R4 represents a member selected from the group consisting of a hydrogen atom and an alkyl group containing from 1 to 2 carbon atoms.
  • R1 and R2 each represents a member 9. selected from theY group consisting. of ahydrogenf atom and anvalkyl group. containingffron'i lrto 2tcarbon1atoms; R3 representsv armember selected fromV the-.group consisting of a hydrogen atom' and azcarbalkoxyl .groupacontaining from 2 to 3 carbonatorns, n represents apositive integer of fromfl to 2, and Zrepresents. the nonfmetallicv atoms necessary to complete a heterocyclic.
  • nucleus selected from the groupconsisting ofthose ofthefbenzothiazole series, those of the naphthothiazole series,.those" of the acenaphtholl1,2]thiazoleiseries,..those of-.the -benzoXazole series, those of the naphthoxazole series,v those of the benzoselenazole series, those of the naphthoselenazole series, thosevof the thiazoline series, those of the benzimidazole series, and those of the 3,3-dialkylindolenine series, and at least onepyridinebase ⁇ selectedflfrom those represented by the following general formula:
  • R4 represents a'member selected fromthezgroup consisting of a hydrogenatom andan alkyl-group. containing from 1 to 2 carbon atoms.
  • a photographic silver halide emulsion@y sensitized with a supersensitizing combination of atleast-'one dye selected from those representedby the following general formula:
  • R represents an alkyl group containing from l to 2 carbon atoms
  • R1 and ⁇ Rzeach represents a.member.s'ef lected from the group consisting; of ahydrogen atom..and an alkyl group containing from 1' to 2 carbon atoms
  • R3 represents a member selected from the group consisting of a hydrogen atom and a carbalkoxyl groupy containing 75A fromi 2 to; 3 carbon; atoms',t. and
  • Z1 represents the.' none metallici atoms necessaryztcrzcomplete :a heterocyclic nufiv cleus ofthe benzothiazole series, and zupyrirline.;baser selected from those represented.
  • a photographic gelatino-silverfhalide developing-.out emulsion sensitized with a supersensitizing combination of a dye selected from those represented by the following general formula:
  • -R represents an ⁇ alkyl groupcontaining from-1 to 2 carbon .atoms andZ represents. the non-metallic atoms necessaryto complete ⁇ a heterocyclic nucleus of the benzothiazole series, and pyridine.
  • R represents ⁇ an alkylgroup containing from 1 to 2 carbon atoms
  • R1 and R2 each represents a member selected from the group consi-sting of a hydrogen atom and an alkyl group containing from 1 to 2 carbon atoms
  • R3 represents a member selected from the group consisting of a hydrogen: atom andxa carbalkoxylrgroup
  • n representsv a .positive integer. of from 1, to 2
  • Z represents. thel non-metallic. atomsnecessary to complete .a heterocyclic.
  • R represents an alkyl group containing from 1 to 2 carbon atoms
  • R1 and R2 each represents a member selected from the group consisting of a hydrogen atom and an alkyl group containing from 1 to 2carbon atoms, ⁇
  • R3 represents a member selected from the group consisting of a hydrogen atom and a carbalkoxyl group con ⁇ taining from 2 to 3 carbon atoms
  • Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzoxazole series, and a pyridine base selected from those represented by the following general formula: i
  • R4 represents a member selected from the group consisting of a hydrogen atom and an alkyl group containing from ⁇ 1 to 2 carbon atoms.
  • a photographic gelatno-silver-halide developingout emulsion sensitized with a supersensitizing combination of -a dye selected from those represented by the following general formula:
  • R represents an alkyl group containing from 1 wherein R represents an alkyl group containing from 11 to 2 carbon atoms, R3 represents a carbalkoxyl group containing from 2 to 3 carbon atoms, and Z represents 12 the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzoxazole series and pyridine.
  • R represents an alkyl group containing from 1 to 2 carbon atoms
  • R1 and R2 each represents a member selected from the group consisting of a hydrogen atom and an alkyl group containing from 1 to 2 carbon atoms
  • R3 represents a member selected from the group consisting of a hydrogen atom and a carbalkoxyl group
  • n represents a positive integer of from 1 to 2
  • Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzimidazole series, and at least one pyridine base selected from those represented by the following general formula:
  • R4 represents ⁇ a member selected from the group consisting of a hydrogen atom and an alkyl group containing from 1 to 2 carbon atoms.
  • R represents an alkyl group containing from l to 2 carbon atoms
  • R1 and R2 each represents a member selected from the group consisting of a hydrogen atom and an alkyl group containing from 1 to 2 carbon atoms
  • R3 represents a member selected from the group consisting of a hydrogen atom and a carbalkoxyl group containing from 2 to 3 carbon atoms
  • Z represents the non-metallic atoms necessary to complete a heterocyclic nucleus of the benzimidazole series
  • a pyridine base selected from those represented by the following general formula:
  • R4 represents a member selected from the group consisting of a hydrogen atom and an alkyl group containing from I to 2 carbon atoms.
  • R represents an alkyl group containmg from 1 2,697,707 Kendall et a1, Dec, 21, 1954 to 2 carbon atoms
  • R3 represents a carbalkoxyl group containing from 2 to 3 carbon atoms
  • Z represents OTHER REFERENCES i the non-metallic atoms necessary to complete ka hetero- M6652
  • TheOfY 0f the PhOtOgFaPhlC PIOCGSS, re-

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3128185A (en) * 1960-01-25 1964-04-07 Eastman Kodak Co Antifoggants for formaldehydehardened photographic layers
US3128184A (en) * 1960-01-25 1964-04-07 Eastman Kodak Co Antifoggants for gold sensitized emulsions in the presence of reduction sensitizers
US3147118A (en) * 1961-03-14 1964-09-01 Gen Aniline & Film Corp Fog reduction in photographic silver halide emulsions
US4293626A (en) * 1977-07-25 1981-10-06 Eastman Kodak Company Electrophotosensitive materials for migration imaging processes

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2398778A (en) * 1942-11-24 1946-04-23 Eastman Kodak Co Sensitized photographic emulsion
US2478369A (en) * 1945-12-29 1949-08-09 Eastman Kodak Co Supersensitized silver halide photographic emulsion
US2697707A (en) * 1950-12-05 1954-12-21 Ilford Ltd Process of producing cyanine dyestuffs

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2398778A (en) * 1942-11-24 1946-04-23 Eastman Kodak Co Sensitized photographic emulsion
US2478369A (en) * 1945-12-29 1949-08-09 Eastman Kodak Co Supersensitized silver halide photographic emulsion
US2697707A (en) * 1950-12-05 1954-12-21 Ilford Ltd Process of producing cyanine dyestuffs

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3128185A (en) * 1960-01-25 1964-04-07 Eastman Kodak Co Antifoggants for formaldehydehardened photographic layers
US3128184A (en) * 1960-01-25 1964-04-07 Eastman Kodak Co Antifoggants for gold sensitized emulsions in the presence of reduction sensitizers
US3147118A (en) * 1961-03-14 1964-09-01 Gen Aniline & Film Corp Fog reduction in photographic silver halide emulsions
US4293626A (en) * 1977-07-25 1981-10-06 Eastman Kodak Company Electrophotosensitive materials for migration imaging processes

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