US2153929A - Modifying the sensitivity of photographic emulsions - Google Patents

Modifying the sensitivity of photographic emulsions Download PDF

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Publication number
US2153929A
US2153929A US81782A US8178236A US2153929A US 2153929 A US2153929 A US 2153929A US 81782 A US81782 A US 81782A US 8178236 A US8178236 A US 8178236A US 2153929 A US2153929 A US 2153929A
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emulsion
sensitivity
solution
thione
group
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US81782A
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English (en)
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Kendall John David
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Ilford Imaging UK Ltd
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Ilford Ltd
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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
    • G03C1/09—Noble metals or mercury; Salts or compounds thereof; Sulfur, selenium or tellurium, or compounds thereof, e.g. for chemical sensitising

Definitions

  • n is a positive integer
  • f 'I'he present invention also includes 'a photographic silver halide emulsion in which one or .30 more of the above mentioned compounds is incorporated.
  • Examples of compounds which may be used according to the present invention are the a and 'y thiones and selenones of any of the hetero- 3 cyclic nitrogen compounds commonly used for the preparation of cyanine dyes, for example unsubstituted and substituted thiazoles, thiazolines, oxazoles, oxazolines, selenazoles, selenazolines, quinolines, indolenines, pyridines, their analogues and homologues including those of the benzene and naphthalene series, and alsoA diazoles such as pyrimidine, described in British ?atent No. 425,609.
  • a convenient method of preparing the thiones 45 and selenones of compounds containing a fivemembered heterocyclic nitrogen ring is 'as follows:
  • the correspondingniercaptan (or selenomercaptan) is alkylated, for example Vwith methyl sulphate in caustic soda solution, to form the thioether (or selenoether) which is then heated l at about. 13G-150 C.
  • reaction mixture is then boiled with a small 55 quantity oi pyridine for about' an hour or until complete solution eiected; on dilution the thione (or selenone) is precipitated and may be purified Yby crystallisation from an alcohol or benzene or by distillation at low pressures. In many cases the yields obtained are almost theoretical when calculated on the quantity .of thloether (or selenoether) employed.
  • the substances may be added at any convenient stage during ⁇ the preparation of the emulsion before coating it on a support, or the flnished coated material may be bathed in a solution of the substance.
  • the amount of substance added and the strength ofthe solution for bathing may vary over quite wide limits according to the substances and types of emulsions used. In general an addition of the order of 80 ccs. of a $6000 solution oi the substance per unit of l/gditres of emulsion equivalent to 250 gms. of silver nitrate will give useful results, but the amount added may be as little as 40 ccs. or as much as 400 ccs. or even more.
  • N-ethyl-dihydroquinoline2thione extends the sensitivity of a silver chloride gelatin emulsion to-about i 4400 with a maximum at about i 4100
  • Nin :Hx N -methyl-dihydroquinoline-i-thione extends the sensitivity of a silver chloride emulsion to about A 4600 with a maximum at about x 4300
  • CHS N-ethyl-dihydropyridine-Z-thione extends the sensitivity of a silver chloride emulsion to about A 4300 with a maximum effect at about i 3900 A.
  • N-methyl-dihydropyridine-Z-thione extends the sensitivity of a silver chloride emulsion to about 7i 4300 with a maximum effect atA about i 3900 A.
  • Fig. 1 is a spectrogram of a silver chloride emulsion containing N-ethyldihydroquinoline-2- thione.
  • Fig. 2 is a spectrogram of a similar emulsion containing N-methyldihydroquinoline-4 -thione.
  • Fig. 3 is a spectrogram of a. similar emulsion containing N-ethyldihydropyridine-Z-thione.
  • Fig. 4 is a spectrogram of a similar emulsion containing N-methyldihydripyridine-2thione.
  • Example I A normal unwashed silver chloride emulsion containing a small proportion, less than 1% together, of silver bromide and silver iodide, was prepared by adding a solution of silver nitrate to a solution of alkali halide in gelatin and ripening the mixture by maintaining it at F. for fifty minutes. The emulsion was then made up to bulk by the addition of gelatin solution, iinished in the normal manner, and then coated on table:
  • the relative exposure time is obtained by interpolation and is expressed as the number of candle meter seconds lexposure to light.
  • N-ethyl-dihydrobenzoxazole 1 'thione except that the speed increase was not quite so large.
  • Example II The experiments described below illustrate the effect of the vaddition of compounds such as described in Example I to an emulsion of low initial sensitivity prepared from inert gelatin.
  • a normal iodobromide emulsion was made up by adding a solution of silver nitrate to a solution of ammonium bromide, potas sium iodide and a gelatin known to yield emulsions of a slow type; the mixture was ripened by maintaining it at a temperature of F. for twenty minutes.' Further quantities of silver nitrate and .gelatin of the same kind were then added and the emulsion was set, shredded,
  • the emulsion was then cooled and coated upon glass plates.
  • a similar batch of emulsion was prepared with the addition of a quantity of a dilute solution of ⁇ N ethyldihydrobenzoxazole 1 thione.
  • the quantity was equivalent to 80 ccs. oi.' solution per unit of 61/2 litres of emulsion equivalent to 250 gms. of silver nitrate, the solution being added partly to the gelatin solution of the alkali halides and partly to the bulk gelatin added after the ripening stage, the quantities added to each being proportional to the quantity of gelatin added at each stage, the emulsion being further treated as above (i. e. washed, digested,.etc.)
  • a photographic silver halide emulsion Vof modiiied sensitivity in which is incorporated in sensitizing amounts N-ethyl-dihydrobenzoxazolel-thione.
  • a photographic silver halide emulsion of modified sensitivity in which is incorporated in sensitizing amounts N-ethyl-dihydrobenzthiazolel-thione.
  • a photographic silver halide emulsion of modified sensitivity in which is incorporated in sensitizing amounts N-ethyl-dihydroquinoline-2- thione.
  • a mono-nuclear heterocyclic mono-nitrogen compound selected from the group consisting of a thiones and sele- .nones of the N-alkyl substituted oxazoles selected v from the group consisting of oXazoles, benzoxaazoles taken from the group consisting of thi azoles, benzthiazoles and naphthathiazoles.
  • a photographic silver halide emulsion con-l taining in sensitizing amounts a mononuclear heterocyclic mono-nitrogen compound selected from the group consisting of the a thiones and Patent No 2,155-, 929.
  • selenones of the N-alkyl substituted thiazoles taken from the group consisting of thiazoles. benzthiazoles and naphthathiazoles.
  • a photographic silver halide emulsion in sensitizing amounts a mono-nuclear heterocyclic nitrogen compound selected from the group consisting of a thiones and selenones of N-alkyl substituted compounds selected from the group consisting of pyridine, quinoline and naphthaquinoline.

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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)
  • Plural Heterocyclic Compounds (AREA)
  • Heterocyclic Carbon Compounds Containing A Hetero Ring Having Nitrogen And Oxygen As The Only Ring Hetero Atoms (AREA)
  • Pyridine Compounds (AREA)
US81782A 1935-05-30 1936-05-25 Modifying the sensitivity of photographic emulsions Expired - Lifetime US2153929A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB15819/35A GB457527A (en) 1935-05-30 1935-05-30 An improved method of modifying the sensitivity of photographic emulsions

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US2153929A true US2153929A (en) 1939-04-11

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US (1) US2153929A (fr)
FR (1) FR806971A (fr)
GB (1) GB457527A (fr)

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Publication number Publication date
GB457527A (en) 1936-11-30
FR806971A (fr) 1936-12-30

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