US2331678A - Differential fixing solution - Google Patents

Differential fixing solution Download PDF

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Publication number
US2331678A
US2331678A US373801A US37380141A US2331678A US 2331678 A US2331678 A US 2331678A US 373801 A US373801 A US 373801A US 37380141 A US37380141 A US 37380141A US 2331678 A US2331678 A US 2331678A
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US
United States
Prior art keywords
silver
solution
bromide
halide
halides
Prior art date
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
Application number
US373801A
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English (en)
Inventor
Jr Wesley T Hanson
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
Original Assignee
Eastman Kodak Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to FR956742D priority Critical patent/FR956742A/fr
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Priority to US373801A priority patent/US2331678A/en
Application granted granted Critical
Publication of US2331678A publication Critical patent/US2331678A/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
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
    • G03C5/38—Fixing; Developing-fixing; Hardening-fixing

Definitions

  • This invention relates to photographic fixing and more particularly to a method for difierentially fixing out silver halide.
  • One object of the present invention is to provide a method for differentially fixing out silver halides. Another object is to describe the application of the method to color photography and black-and-white photography. Other objects appear hereinafter.
  • the solutions which are used contain certain well-known solvents for silver halides such as ammonia, sodium chloride, sodium thiocyanate, sodium sulfite, sodium bisulfite and mixtures of these.
  • a halide such as potassium bromide or a silver halide is added to prevent the solution of one or more silver halides.
  • Some salts diflicultly soluble in water can be dissolved in certain salt solutions due to the formation of a complex ion composed of the cation of the difiicultly soluble salts and one of the constituents of the solvent solution.
  • silver bromide is soluble in a hypo solution due to the formation of the silver thiosulfate complex ion, or' in a thiocyanate solution due to the formation of silver thiocyanate complex.
  • the extent to which a diflicultly soluble salt can be dissolved in such a solution is dependent on the solubility product of the salt and on the dissociation constant for the complex.
  • the concentration of the silver ions in the equilibrium with the silver thiosulfate complex ions is muchsmaller than the silver ion concentration in equilibrium with bromide ion, and if the silver bromide is put into a thiosulfate ion solution, the silver thicsulfate complex ion is formed until the silver ion concentration is in equilibrium both with the bromide ion and the silver thiosulfate complex ion. If the solubility product is smaller than the dissociation constant of the complex, very little of the difilculty soluble salt will be dissolved by the solution containing the complex forming ion.
  • This method of differentially dissolving certain salts of the same cation has a wide application and can be specifically applied to photographic processes in which three different salts of silver are used, such as silver chloride, silverbromide,
  • silver iodide For example, if an ammonium hydroxide solution or a saturated sodlumchloride solution is saturated with silver bromide, this solution can be used for fixing out a silver chloride emulsion in the presence of a silver bromide emulsion without appreciable efiect on the latter. Or, by saturating a solution of hypo, potassium thiocyanate, or sulfite with silver iodide, the solution can be used for fixing out a silver bromide or silver chloride emulsion in the presence of a silver iodide emulsion.
  • solvent solutions can be generalized into any solution having an ion which forms a soluble complex with silver ion and from which the dissociation constant of the complex is of the same order of magnitude as the solubility product of silver chloride or silver bromide.
  • silver halide solvent solutions may contain halides of metals other than silver such as potassium bromide or potassium iodide, in an of potassium bromide; but this solution would not fix out silver bromide in the presence of silver iodide.
  • halides of metals other than silver such as potassium bromide or potassium iodide, in an of potassium bromide; but this solution would not fix out silver bromide in the presence of silver iodide.
  • a solvent solution containing sodium thiosulfate the correct amount of iodide is added, both silver chloride and silver bromide may be fixed out in the presence of silver iodide.
  • the silver images may be first bleached with a less powerful oxidizing solution to silver halide, preferably silver chloride or silver bromide, by well-known methods, and then treated with the differential fixing solutions of the invention whereby the silver halide corresponding to the silver of the negative image is removed without affecting the silver halide to be used for the development of the posi tive image in color.
  • a less powerful oxidizing solution to silver halide preferably silver chloride or silver bromide
  • a negative image is recorded upon a sensitive material and after negative development, according to my invention, the negative silver image may be bleached to silver halide different than that of the original emulsion and removed in the presence of the original emulsion by application of a difierential fixing solution of the invention.
  • the positive image may be then produced in the usual manner from the sensitive silver halide remaining in the positive image area.
  • Example 1 Silver chloridemay be fixed out in the presence of silver bromide by treatment with the following solution.
  • Example 2 Silver chloride may be fixed out in the presence of silver bromide or silver iodide by treatment with the following solution.
  • a method for differentially fixing out silver halides which comprises saturating an ammonia solution with silver bromide and then treating a photographic element containing silver bromide and silver chloride with said solution whereby silver chloride may be fixed out in the'presence of silver bromide.
  • a method for, differentially fixing out silver halides which comprises adding silver iodide to a thiosulfate solution in an amount sufilclent that a more soluble silver halide may be fixed out in the presence of silver iodide and then treating a photographic element containing a group of silver halides including silver iodide with said solution whereby a more soluble silver halide is fixed out in the presence of silver iodide.
  • a method for differentially fixing out silver halides which comprises adding silver iodide to a thiosulfate solution in an amount suilicient that silver bromide may be fixed out in the presence of silver iodide and then treating a photographic element containing silver bromide and silver iodide with said solution whereby silver bromide is fixed out in the presence of silver iodide.
  • a method for differentially fixing out silver halides which comprises saturating a thiosulfate solution with silver iodide and then treating a photographic element containing silver bromide and silver iodide with said solution whereby silver bromide may be fixed out in the presence of silver iodide.
  • a method for difierentially fixing out silver halides which comprises adding potassium bromide to an ammoniacal bisulfite solution in an amount sufiicient that silver chloride may be fixed out in the presence of silver bromide and then treating a photographic element containing silver chloride and silver bromide with said solution whereby silver chloride is fixed out in the presence of silver bromide.
  • a method for differentially fixing out silver halides which comprises adding to a silver halide solvent solution a halide having an anion in common with the less soluble of the group of silver halides in an amount sufiicient to render the less soluble silver halide insoluble in said solution, and then treating a photographic element containing said group of silver halides with said solution whereby a more soluble silver halide of anion other than in said solution is fixed out in the presence of a less soluble silver' halide of said group of silver halides.
  • a method for differentially fixing out silver halides which comprises adding a halide having an anion in common with the less soluble of a group of silver halides to an ammonia solution in an amount sufiicient to render the less soluble silver halide insoluble in said solution, and then treating a photographic element containing said group of silver halides with said solution whereby a more soluble silver halide of anion other than in said solution is fixed out in the presence of a less soluble silver halide of said group of silver halides.
  • a method for difierentially fixing out silver halides which comprises addinga halide having an anion in common with the less soluble of a group of silver halides to a thiosulfate solution in an amount sufiicient to render the less soluble silver halide insoluble in said solution, and then treating a photographic element containing said group of silver halides with said solution whereby a more solublesilver halide of anion other than in said solution is fixed out in the presence of a less soluble silver halide of said group of silver halides.
  • a method for differentially fixing out silver halides which comprises adding a halide having an anion in common with the less soluble of a.
  • a photographic element concontaining a group of silver halides with a solvent solution for silver halide containing a halide having an anion in common with the less soluble oi said group of silver halides in an amount sufficient to render the less soluble silver halide insoluble in said solution, and then treating said; photographic element with said solution whereby a more soluble silver halide of anion other than in said solution is fixed out in the presence of a less soluble silver halide of said group of silver halides.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Silver Salt Photography Or Processing Solution Therefor (AREA)
US373801A 1941-01-09 1941-01-09 Differential fixing solution Expired - Lifetime US2331678A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
FR956742D FR956742A (enrdf_load_stackoverflow) 1941-01-09
US373801A US2331678A (en) 1941-01-09 1941-01-09 Differential fixing solution

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US373801A US2331678A (en) 1941-01-09 1941-01-09 Differential fixing solution

Publications (1)

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US2331678A true US2331678A (en) 1943-10-12

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US373801A Expired - Lifetime US2331678A (en) 1941-01-09 1941-01-09 Differential fixing solution

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US (1) US2331678A (enrdf_load_stackoverflow)
FR (1) FR956742A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2748000A (en) * 1954-04-01 1956-05-29 Eastman Kodak Co Removing silver and silver halide from photographic elements

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2748000A (en) * 1954-04-01 1956-05-29 Eastman Kodak Co Removing silver and silver halide from photographic elements

Also Published As

Publication number Publication date
FR956742A (enrdf_load_stackoverflow) 1950-02-06

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