US2346095A - Chemical sensitizing of photographic emulsions - Google Patents

Chemical sensitizing of photographic emulsions Download PDF

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Publication number
US2346095A
US2346095A US435666A US43566642A US2346095A US 2346095 A US2346095 A US 2346095A US 435666 A US435666 A US 435666A US 43566642 A US43566642 A US 43566642A US 2346095 A US2346095 A US 2346095A
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United States
Prior art keywords
emulsion
sensitizing
emulsions
sensitivity
photographic
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US435666A
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English (en)
Inventor
Weissberger Arnold
Burt H Carroll
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
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Eastman Kodak Co
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Filing date
Publication date
Priority to FR956682D priority Critical patent/FR956682A/fr
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Priority to US435666A priority patent/US2346095A/en
Application granted granted Critical
Publication of US2346095A publication Critical patent/US2346095A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C1/10—Organic substances

Definitions

  • This invention relates to photographic emulsions and particularly to materials used in the preparation of such emulsions.
  • sensitizing of photographic emulsions is of two general types; chemical sensitizing, in which the sensitivity of the emulsion is increased in the spectral region to which the silver halide is originally sensitive, and optical sensitizing, in
  • the present invention relates to the former type of sensitizing.
  • a further object is to provide a method in which such materials are used to improve photographic emulsions, especially developing out emulsions, with respect to light sensitivity, by which term we include their ability to give the earliest visible impression or image with the minimum exposure or their ability to produce the maximum density after a given exposure or both.
  • a still further object is to provide colloid products such as gelatins, the usefulness of which for forming light-sensitive photographic emulsions is'greatly increased and controlled by the use of our sensitizing materials.
  • a still further object is to provide a method for enhancing the light sensitivity of photographic emulsions immediately after the addition of the sensitizing compounds.
  • Other objects are to increase the general light sensitivity of such photographic emulsions throughout the spectral ranges to which they are normally sensitive and to obtain more stable emulsions through the use of our sensitizingagents. Other objects will appear from the following description of our invention.
  • Our sensitizing material may be used in many Ways. It may be incorporated in emulsions or in colloids used in the preparation of the emulsions. It can also enter the emulsion mixed with other ingredients, organic or inorganic. It increases the light-sensitivity of various emulsions having different speeds or other distinctive characteristics. While it may be added at different stages of emulsion manufacture, nevertheless it can be very conveniently mixed with the emulsion when the latter is otherwise complete and ready for coating. Since its action is immediate when incorporated, the coating need be delayed only long enough to mix the sensitizing material with it.
  • alkoxymethylene-fi-diketones which we have found suitable for the purpose of sensitizing and stabilizing photographic emulsions include ethoxymethyleneacetyl acetone and butoxymethyleneacetyl acetone as well a other compounds of this general class.
  • the proportion of sensitizing material added to the emulsions will vary according to the concentrations of the sensitizing material and according to the increase in light sensitivity desired.
  • the addition of the alkoxymethylene-c-diketones to photographic emulsions in amounts to the order of 10 mg. to 50 mg. Per liter of emulsion tends to increase the threshold speed by .as much as in some cases. Larger amounts of sensitizing agent can be used and smaller amounts can also be used if only slight increase in sensitivity is desired.
  • sensitivity canreadily be brought up to standard by mixing our sensitizing material with them, the proportion varying with the increase necessary to produce a uniform product.
  • the increase in sensitivity can be effected in one step by thoroughly stirring all of the sensitizing material into the emulsion at one time or it may be incorporated in successive steps.
  • the emulsion With its light sensitivity increased by the use of our material, the emulsion is melted to the desired degree and is coated on the support, such as suitably subbed glass, film or paper, in the usual way.
  • gelatin used for photographic emulsion making may be used in the example above, hard ones being very useful.
  • the temperatures given are, of course, readjusted if the particular gelatin employed has melting and setting point which deviate considerably from the usual ones, this adjustment being a matter of routine control.
  • Our sensitizers can be used to increase the general light-sensitivity of ordinary blue-sensitive photographic emulsions or they can be used for increasing the sensitivity of orthochromatic, panchromatic, X-ray and other pecial emulsions. It is evident, therefore, that they can be used in conjunction with optical sensitizers although they do not act as optical sensitizers for the emulsion.
  • Our sensitizers act to increase the light sensitivity independently of ripening.
  • ot er colloids may be used in the preparation of the photographic emulsion such as collodion, agar, synthetic resins and cellulose esters.
  • the principle of the invention is applicable to silver chloride and chlorobromide emulsions as well as to silver bromide and silver bromoiodide emulsions and to mixtures of any two or more of them.
  • a photographic emulsion comprising a colloidal material having particles of silver halide dispersed therein, and an added sensitizing compound upon which at least a part of the light sensitivity of the emulsion depends, the sensitizing compound being an alkoxy methylene-fi-diketone.
  • a photographic developing-out gelatino-si'lver halide emulsion of high light sensitivity containing as a sensitizing compound from about 10 milligrams to about 50 milligrams per liter of emulsion of an alkoxy methylene acetyl acetone.
  • a photographic developing-out gelatino-silver halide emulsion of high light sensitivity containing as a salsitizing compound from about 10 milligrams to about 50 milligrams per liter of emulsion of ethoxymethylene acetyl acetone.
  • a photographic developing-out gelatino-silver halide emulsion of high light sensitivity containing as a sensitizing compound from about 10 milligrams to about 50 milligrams per liter of emulsion of butoxymethylene acetyl acetone.
  • the method of increasing the light sensitivity of said emulsion by incorporating in it from about 10 milligrams to about 50 milligrams per liter of emulsion of ethoxymethylene acetyl acetone.
  • the method of increasing the light-sensitivity which comprises incorporating therein from about 10 milligrams to about 50 milligrams per liter of emul- 45 sion of butoxymethylene acetyl acetone.

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
US435666A 1942-03-21 1942-03-21 Chemical sensitizing of photographic emulsions Expired - Lifetime US2346095A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
FR956682D FR956682A (enrdf_load_stackoverflow) 1942-03-21
US435666A US2346095A (en) 1942-03-21 1942-03-21 Chemical sensitizing of photographic emulsions

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US435666A US2346095A (en) 1942-03-21 1942-03-21 Chemical sensitizing of photographic emulsions

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US2346095A true US2346095A (en) 1944-04-04

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FR (1) FR956682A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939789A (en) * 1958-06-06 1960-06-07 Gen Aniline & Film Corp Fog reduction in photographic silver halide emulsions
US3078163A (en) * 1959-12-02 1963-02-19 Gevaert Photo Prod Nv Spot prevention in light-sensitive silver halide emulsion layers
US3201253A (en) * 1961-05-29 1965-08-17 Eastman Kodak Co Photographic emulsions containing delta-polycarbonyl sensitizers

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939789A (en) * 1958-06-06 1960-06-07 Gen Aniline & Film Corp Fog reduction in photographic silver halide emulsions
US3078163A (en) * 1959-12-02 1963-02-19 Gevaert Photo Prod Nv Spot prevention in light-sensitive silver halide emulsion layers
US3201253A (en) * 1961-05-29 1965-08-17 Eastman Kodak Co Photographic emulsions containing delta-polycarbonyl sensitizers

Also Published As

Publication number Publication date
FR956682A (enrdf_load_stackoverflow) 1950-02-02

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