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
  • G03C1/015—Apparatus or processes for the preparation of emulsions

Definitions

• This invention relates to methods of preparing photographic silver halide emulsions and more particularly to a process of forming photographic emulsions wherein ray-products are removed; for example, by means of vacuum.
• ammonium salts of organic and inorganic oxygen-containing acids such as ammonium nitrate, carbonate, sulfate, citrate, acetate or oxalate are incorporated into the reaction mixture, not only is the silver plating tendency of the system reduced but also the explosive characteristic of the system, particularly of dried residues therelessening the danger Another method disclosed of, is destroyed.
• ammonium carbonate is utilized as the inhibitor, we are able to employ appreciably less ammonia in the conversion of silver oxide to the ammono compound.
• ammoniacal silver oxide solution may be used for forming emulsions from which all reaction products may be separated from the silver halide by vaporization as well as by washing.
• One object of our invention therefore is to provide non-explosive ammoniaoal silver oxide systems of particular use in forming silver halide emulsions. Another object is to provide agents which inhibit the detonatin and plating tendarmies of ammoniacal silver oxide systems. A further object is to provide methods of making photographic emulsions utilizing the inhibitors of the invention. Other objects include using vaporization methods for the purification of such emulsions as will be apparent from the following description of our invention.
• the objects of our invention are accomplished in part by incorporating ammonium salts into ammoniacal silver oxide solutions, preferably before conversion of the silver oxide to the ammono compound.
• the inhibiting effect of the ammonium salts is due to a buffering effect. That is, it appears necessary, in order to prevent violent decomposition of the dried ammoniated silver oxide system, to decrease the pH below that of the unstable system, and this is accomplished according to our invention by the addition of water-soluble ammonium salts or" oxygen-containing acids such as ammonium nitrate, ammonium sulfate, ammonium carbonate, etc.
• Ammoniated silver carbonat systems are not explosive and a pH value of 12.0 was recorded for the system obtained, when 0.1 equivalent of silver carbonate was converted with 10% excess ammonia and diluted to
• the ammonium salt inhibitors are effective in a fairly wide range of concentration givin satisfactory protection in the majority of cases within a range of from about 0.5 to 1.0 equivalent of ammonium salt per equivalent of silver nitrate which had been converted to silver oxide although more salt can be used as shown in the table following, the starred values of which indicate preferred amounts.
• the various ammonium salt vary somewhat in their eiiioiency as inhibitors may be seen from the following table illustrating results obtained with typical ammonium salts.
• the above data were obtained by converting samples of 1.2 parts of silver nitrate in ten parts of water to silver oxide by treatment with 0.31 part of sodium hydroxide in five parts of water followed by washing and centrifuging the precipitates. Thereafter, varying amounts of 20 per cent solutions of the ammonium salts were added to the individual samples followed by the amount of concentrated. ammonium hydroxide required to dissolve the precipitated silver oxide and diluting to cc.
• the protection against detonation afforded by the treatments was ascertained by evaporation of portions of the samples to dryness and attempting to explode the dried residues. The degree of protection was calculated from the number of detonations obtained and the number of trials made.
• Example Silver oxide is prepared in the usual manner by treatin an aqueous solution of silver nitrate with an excess of aqueous sodium hydroxide solution. The precipitate is then washed several times and to 0.125 mol of moist silver oxide is added a solution or" 0.073 mol of ammonium carbonate monohydrate in 170 cc. of water. The mixture is then treated with 88 cc. of 28 per cent aqueous ammonia solution and then diluted to 380 cc. The solution of the complex silver compound obtained is added to a solution of 0.264
• one embodiment of our invention includes making photographic emulsions by reacting an aqueous ammonia solution of silver oxide in the presence of a lyophilic colloid such as gelatin and an ammonium salt of an oxygen-containing acid such as ammonium carbonate, with one or more alkali metal or alkaline earth metal halides such as sodium bromide or calcium bromide, with hydrogen halides such as hydrobromic or hydrochloric acids and amine halides such as pyridinium hydrobromide, ammonium bromide, chloride or iodide and other halides having the structure where X is a halogen atom and R, R1, R2, and R3 each represent a member selected from the group consisting of a hydrogen atom and an alkyl group having from 1-% carbon atoms, the sum total of the carbon atoms in the R groups being from 0-4, then removing volatile product from the resulting reaction mixture by means of washing or a vaporization method such as by
• ammonium carbonate ammonium acetate and ammonium sulfate as the protective agents against the detonating and plating efiects mentioned.
• ammonium carbonate we prefer ammonium carbonate because it is readily removable from emulsions by vacuum treatment as well as by washing in the conventional manner.
• Ammonium acetate ammonium sulfate are effective, as has been shown previously, but their use is limited to where it is not necessary to produce completely saltfree emulsions by vaporization methods, but of course they may be utilized if washing employed for purification of the emulsion. How ever, in these cases we may use evacuation for removal of excess ammonia, if desired, and the salt content of the emulsion can be kept to a minimum by use of the least amount of the salt which will furnish the desired protection against detonation.
• ammoniacal as used in reference to silver oxide solutions, we mean solutions in which silver oxide is converted to the ammono compound by means of ammonia or a lower aliphatic amine, and ammoniated as applied to silver oxide denotes silver oxide reacted with ammonia or amines to the extent that the silver compound is in the form useful for making silver halide emulsions and dried residues thereof can be detonated.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium acetate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the resulting reaction mixture,
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solu- 4 tion, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium acetate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the resulting reaction mixture by vaporization.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium acetate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing vola tile product from the resulting reaction mixture by vacuum.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving 1 moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium sulfate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the resulting reaction mixture.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aquous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium sulfate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the resulting reaction mixture by vaporization.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium sulfate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the resulting reaction mixture by vacuum.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium carbonate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide and removing volatile product from the resulting reaction mixture.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium carbonate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide and removing volatile product from the resulting reaction mixture by vaporization.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium carbonate, forming silver halide by reaction of the resulting solution in the presence Of a silver halide peptizing hydrophilic colloid with a water-soluble halide and removing volatile product from the resulting reaction mixture by vacuum.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of an 7 ammonium salt selected from the group consisting of ammonium carbonate, ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium citrate, and ammonium oxalate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the resulting reaction mixture.
• the method of making a photographic, silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of an ammonium salt selected from the group consisting of ammonium carbonate, ammonium nitrate, ammonium sulfate, ammonium acetate, am-
• monium citrate, and ammonium oxalate form- L ing silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the resulting reaction mixture by means of vaporization.
• the method of making a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of an ammonium salt selected from the group consisting of ammonium carbonate, ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium citrate, and ammonium oxalate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the resulting reaction mixture by means of vacuum evacuation.
• an ammonium salt selected from the group consisting of ammonium carbonate, ammonium nitrate, ammonium sulfate, ammonium acetate, ammonium citrate, and ammonium ox
• the method of preparing a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium nitrate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a water-soluble halide, and removing volatile product from the reaction mixture.
• the method of preparing a photographic silver halide emulsion which comprises preparing an ammoniacal solution of silver oxide by dissolving moist silver oxide in an aqueous ammonia solution, adding to the ammoniacal solution from about 0.5 to 1.0 molecular equivalent, based on the silver salt used in making the oxide, of ammonium citrate, forming silver halide by reaction of the resulting solution in the presence of a silver halide peptizing hydrophilic colloid with a Water-soluble halide, and removing volatile product from the reaction mixture.

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• 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)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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Citations (10)

• 0
  • BE BE503528D patent/BE503528A/xx unknown
• 1948
  • 1948-12-31 US US68753A patent/US2678883A/en not_active Expired - Lifetime
• 1949
  • 1949-02-25 GB GB5263/49A patent/GB676746A/en not_active Expired
• 1951
  • 1951-05-29 FR FR1055880D patent/FR1055880A/fr not_active Expired

Patent Citations (10)

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