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
  • G03C1/34—Fog-inhibitors; Stabilisers; Agents inhibiting latent image regression
  • G03C1/346—Organic derivatives of bivalent sulfur, selenium or tellurium

Definitions

• This invention relates to a fog-inhibiting agent or stabilizer for photographic silver halide emulsions, and a method of preventing scum in photographic silver halide emulsions containing certain types of sensitizers.
• Fog depends both on the emulsion and the conditions of development; for a given emulsion it increases with the degree of development. With constant development conditions, it tends to increase with. time, temperature and relative humidity of storage conditions; it is common practice to make accelerated tests of the stability of photographic emulsions by storage at increased temperature or humidity, or both. It is, of course, desirable to have V.
• Fog usually appears over the whole area of the sensitive coating, but when severe, it frequently is non-uniform. Fog may also be caused by exposure to chemicals, for example, hydrogen sulfide and other reactive sulfur compounds, hydrogen peroxide vapor, and strongly reducing materials. While antifoggants and stabilizers may protect, to some extent, against such effects, it is normally understood that an antifoggant protects against spontaneous growth of fog during prolonged storage or storage at temperatures and humidities, or during development to maximum contrast and speed, or both.
• an object of our invention to provide a method of stabilizing photographic silver halide emulsions.
• a further object is to maintain the sensitivity and fog of silver halide emulsions at or close to initial optimum values under keeping conditions of high temperature and humidity.
• Another object is to provide a means of reducing or removing scum which forms during development of high-speed negative emulsions containing alkylene oxide polymers as emulsion sensitizers.
• Still another object is to provide photographic silver halide emulsions containing a stabilizer or fog-inhibiting agent.
• photographic silver halide emulsions can be stabilized against the formation of spontaneous fog by incorporating in the emulsions 5- thioctic acid.
• This compound can be illustrated by the following formula:
• the 5- thioctic acid can be added to the emulsion during the process of manufacture to avoid loss of sensitivity and to inhibit the growth of fog with passage of time under non-ideal conditions of storage.
• a solution of the S-thioctic acid of the invention when added in suitable concentration, before coating, to unsensitized, chemically sensitized, or optically sensitized photographic emulsions does not appreciably alfect the sensitometric values for sensitivity and fog when measurements are made soon after coating.
• sensitometric measurements are made at appreciable intervals of time, at elevated temperatures and dry or somewhat humid conditions, this compound does stabilize photographic speed and maintain fog at a low level.
• the preparation of silver halide emulsions involves three separate operations: (1) the emulsification and digestion or ripening of the silverihalide, (2) the freeing of the emulsion from excess soluble salts, usually by washing, and (3) the second digestion or after-ripening to obtain increased sensitivity. '(Mees, The Theory of the Photographic Process (1942).). We prefer to add the fog-inhibiting agents after the final digestion or afterripening, although they can advantageously be added prior to digestion. I I I
• the photographic emulsions used in practicing our invention are generally of the developing-out type; also, it is to be understood that photographic emulsions of varying halide content can advantageously be used.
• the 5-thioctic acid used in our invention has been found particularly useful when employed in conjunction with gelatino-silver-bromiodide emulsions, although it can also be advantageously employed in other silver halide emulsions, such as gelatinosilver-chloride, bromide, chlorobromide, chlorobromiodide, etc.
• the emulsions can also be chemically sensitized by any of the accepted procedures.
• the emulsions can be digested with naturally active gelatin, or sulfur compounds can be added such as those described in Sheppard US. Patent 1,574,944 and U.S. 1,623,499, and Sheppard and Brigham US. Patent 2,410,689.
• the emulsions can also be treated with salts of the noble metals such as ruthenium, rhodium, palladium, iridium and platinum, all of which belong to group VIII of the periodic table of elements and have an atomic weight greater than 100.
• Representative compounds are ammonium chloro-palladate, potassium chloroplatinate and sodium chloropalladite, which are used for sensitizing in amounts below that which produces any substantial fog inhibition, as described in Smith and Trivelli US. Patent 2,448,060, and as antifoggants in higher amounts, as described in Trivelli and Smith US. Patents. 2,566,245 and 2,566,263.
• the emulsions can also be chemically sensitized with gold salts as described in Waller and Dodd US. Patent 2,399,083, or stabilized with gold salts as described in Patented Aug.-9, 1960 3 Damschroder U.S. Patent 2,597,856 and Yutzy and Leermakers U.S. Patent 2,597,915.
• Suitable compounds are (potassium chloroaurite, potassium aurithiocyanate, potassium chloroaurate, auric trichloride and 2-aurosulfobenzothiazole methochloride.
• the emulsions can also be chemically sensitized with reducing agents such as stannous salts (Carroll U.S. Patent 2,487,850), polyamines such as diethylene triamine (Lowe and Jones U.S. Patent 2,518,698), polyarnines, such as spermine (Lowe and Allen U.S. Patent 2,521,925), or bis-(,B-aminoethyl) sulfide and its watersoluble salts (Lowe and Jones U.S. Patent 2,521,926).
• reducing agents such as stannous salts (Carroll U.S. Patent 2,487,850), polyamines such as diethylene triamine (Lowe and Jones U.S. Patent 2,518,698), polyarnines, such as spermine (Lowe and Allen U.S. Patent 2,521,925), or bis-(,B-aminoethyl) sulfide and its watersoluble salts (Lowe and Jones U.S. Patent 2,521,926).
• the emulsions can also be stabilized with the mercury compounds of Allen, Byers and Murray U.S. Patent 2,728,663, Carroll and Murray U.S. Patent 2,728,664, and Leubner and Murray.U.S. Patent 2,728,665.
• the S-thioctic acid is effective in the presence or absence of optical sensitizing dyes. Since optical sensitizing may affect stability of emulsions with respect to sensitivity, fog and latent image changes, the action of the S-thioctic acid of this invention is not completely independent of optical sensitizing or other emulsion variables. We have found, however, that both unsensitized emulsions and emulsions sensitized with cyanine and developed for 18 minutes at 68 F. in a developer (D-l9) having the following composition:
• S-thioctic acid useful in practicing our invention can be prepared as described in Jour. Am. Chem. Soc., vol. 76 (1954), page 1828.
• 6-thioctic acid does not have the desirable stabilizing properties of 5-thioctic acid, particularly when emulsions containing the same are subjected to forced development.
• a comparison of the properties of the two acids in this respect is given in Table I below. These data were obtained using an ordinary high speed bromiodide emulsion chemically sensitized with sulfur and gold compounds, and spectrally sensitized with a cyanine dye. A separate series of tests was run for an identical batch of emulsion which had been chemically sensitized with the oleyl ether of polyethylene glycol (PEG) (molecular weight about 1500) (0.75 g./mol. AgX). This particular chemical sensitizer provides useful speed increases, but also produces an increase in fog.
• PEG polyethylene glycol
• each series of emulsions which had been coated on a cellulose acetate support were exposed on a Kodak Ib sensitomer
• the same type of emulsion used in arriving at the data in Table I above was treated with S-thioctic acid in the amounts shown in the following table, and the treated emulsions compared with a similar batch containing no S-thioctic acid, both where the emulsions contained no chemical sensitizer (the same oleylether of polyethylene glycol used in Table l) and where the emulsions contained this sensitizer in the same amounts used in Table I.
• a portion of each emulsion was coated on a cellulose acetate support and incubated for one week at a temperature of F. and constant relative humidity (obtained by placing the coatings in closed containers, the ambient temperature being about 70 F. and relative humidity about 55% prior to sealing the containers).
• the efficiency of the S-thioctic acid was determined by measuring the speed, gamma and fog of the incubated emulsions containing 5-thioctic acid and comparing these measurements with those of the same batch of emulsion before incubation. Similar measurements were made with a photographic emulsion containing no S-thioctic acid both before'and after incubation. The coatings were then exposed on an intensity scale sensitometer (Eastman Type Ib) and developed for 5 minutes in a developer having the following composition:
• alkylene oxides with aliphatic acids e.g., lauric acid and glycine
• condensation products of alkylene oxides with aliphatic amines or amides e.g., glycine and lauryl amide
• condensation products of alkylene oxides with phe nols e.g., phenol.
• the preparation of these condensation products is described in U.S. Patent 1,970,578, Condensation products of alkylene oxides with hexitol ring Table Ia 5-Thioctic Oleyl Fresh Tests Incubation, 1 Week at cid, Ether, 120 F. Coating g./mol g./mol.
• the S-thioctic acid useful in practicing our invention dehydration products as described in U.S. Patent can be used in various kinds of photographic emulsions. In addition to being useful in ordinary non-sensitized emulsions, it can also be used in orthochromatic, panchromatic and X-ray emulsions. If used with sensitizing dyes, it can be added to the emulsion before or after the dyes are added. Suitable dispersing agents for the silver halide emulsions stabilized according to our invention comprise gelatin, or other colloids, such as collodion, albumen, cellulose organic derivatives, synthetic resins, etc.
• the optimum amount of S-thioctic acid as a fog-inhibiting agent can be determined by making the customary tests employed in emulsion making. Of course, the optimum amount for a given emulsion will vary depending on the presence of emulsion addenda, such as chemical sensitizers, optical sensitizers, etc. In general, we have found that from 0.25 to 4.0 g. of S-thioctic acid'per mole of silver halide is sufficient for the purposes of our invention.
• the S-thioctic acid of our invention is particularly useful in inhibiting or preventing the formation of scum during the development of high-speed negative emulsions which have been sensitized with an alkylene oxide polymer.
• the alkylene oxide polymers used .to sensitize the emulsions may be of various types. from which the polymers are derived contain from 2 to 4 carbon atoms, e.g., ethylene oxide, propylene oxide and butylene oxide. The preparation of polymers from these compounds is described in Ellis, The Chemistry of Synthetic Resins (1935), pages 990 to 994. These compounds are also referred to as polyalkylene glycols and their use as sensitizers for silver halide emulsions is described in U.S. Patents 2,423,549 and 2,441,389.
• the alkylene oxide derivatives may be prepared by condensing an organic compound containing an active hydrogen atom with an alkylene oxide polymer, or by condensing the active hydrogen compound with the alkylene oxide during the polymerization of the latter material.
• alkylene oxides may also be used to sensitize the emulsions, e.g., condensation products of alkylene oxide with organic compounds containing an active hydrogen atomf
• active hydrogen organic compounds i.e., compounds in which a hydrogen atom may be replaced by reaction of the compound with metallic sodium, methylmagnesium iodide, etc.
• active hydrogen organic compounds include alcohols, amines, mercaptans, acids, amides, hydrocarbons, such as acetylene, and compounds having The alkylene oxides the active hydrogen in a methylene group such as dibenzoylmethane.
• condensation products of alkylene oxide with glycols such as those having from 8 to 18 carbon atoms as described in U.S. Patent 2,240,472 and British Patent 443,559 as well as condensation products of alkylene oxides with aliphatic alcohols, condensation products of 2,400,532 may also be employed.
• the polyalkylene oxide or derivative of alkylene oxide should have :a molecular Weight of at least 300.
• Condensation products of ethylene oxide with long chain alcohols, acids, amines or amides should have a molecular weight of about 700.
• the best results are obtained with the condensation products of ethylene oxide with long chain compounds having a chain length of 12 or more carbon atoms and with ethylene oxide polymers having a molecular weight of 1500 to 4000 or more.
• alkylene oxide derivatives used to sensitize the emulsions may be illustrated by .the following specific examples, although our invention is in no way limited to the use of these specific compounds.
• velopers are used with emulsions sensitized with polyethylene glycols.
• Polyvinyl pyrrolidone may be incorpo rated in such emulsions in amounts up to about grams per mole of silver or in a gelatin overcoating for the emul.
• Polyvinyl pyrrolidone may be used in the developing solution in amounts of from about 0.05 gram to 0.5 gram per liter of developer.
• sensitizer 1 is the oleyl ether of polyethylene glycol having a molecular weight of about 1500
• sensitizer 2 is polyethylene glycol having a molecular weight of about 1540
• sensitizer 3 is polyethylene glycol-bis-carboglutamic acid sodium salt
• sensitizer 4 is 3,6,9,12,l5,18,2l,24-octaoxahexacosane-bispyridinium perchlorate.
• the speed, gamma and fog for At the lower concentrations the polyvinyl pyrrolidone not only lowers fog but changes the image tone from brown to black.
• a photographic silver halide emulsion containing (a) an alkylene oxide polymer selected from the group consisting of polyalkylene glycols and condensation products of alkylene oxide containing from 2 to 4 carbon atoms with an organic compound containing an active hydrogen atom selected from the class consisting of alc0-' hols, phenols, amines, mercaptans, acids, amides, and hydrocarbons, said alkylene oxide polymer having a molecthe coatings are indicated in the table, these data being 5 ular weight of at least 300, and (b) S-thioctic acid.
• Alkylene oxide polymers containing anionic and cationic groups can also be used in our invention, including quaternary ammonium, quaternary sulfonium and quaternary phosphoniurn derivatives.
• Sensitizer 3 in Table III is an example of an anionic alkylene oxide derivative.
• Sensitizer 4 in Table III is an example of a quaternary ammonium alkylene oxide polymer derivative.
• Other examples of anionic and cationic derivatives of alkylene oxide polymers which can be employed in our invention can be prepared as described in Carroll, Sagal and Beavers US. application Ser. No. 627,135, filed December 10, 1956. Such derivatives generally have a molecular weight of about 200 to 1500. Other examples of such polymers and their derivatives are shown in Carroll, Graham, Elins and Wilson US. application Serial No. 627,136, filed December 10, 1956.
• fog may be reduced and that scum on the surface of the film may be suppressed, by incorporating polyvinyl pyrrolidone in an emulsion which has been sensitized with polyethylene glycols as described above. Similar reduction of fog and suppression of scum may be accomplished in emulsions so sensitized by incorporating the polyvinyl pyrrolidone in a protective gelatin overcoat on the emulsion, or in the developer in which the emulsion is developed.
• Scum on the surface of the film is particularly promoted by developers containing the thiocyanate ion such as Kodak Developer DK 20, especially when such de- (a) an ethylene oxide polymer selected from the group consisting of polyethylene glycols and condensation products of ethylene oxide with organic compounds containing an active hydrogen atom selected from the class consisting of alcohols, phenols, amines, mercaptans, acids, amides, and hydrocarbons, said ethylene oxide polymer having a molecular weight of at least 300, and (b) 5- thioctic acid.
• developers containing the thiocyanate ion such as Kodak Developer DK 20
• an ethylene oxide polymer selected from the group consisting of polyethylene glycols and condensation products of ethylene oxide with organic compounds containing an active hydrogen atom selected from the class consisting of alcohols, phenols, amines, mercaptans, acids, amides, and hydrocarbons, said ethylene oxide polymer having a molecular weight of at least 300,
• a photographic gelatino-silver-halide developing-out emulsion containing (a) a condensation product of ethylene oxide and a monohydric aliphatic alcohol containing at least 12 carbon atoms, said condensation product having a molecular weight of at least 1500 and (b) 5 thioctic acid.
• a photographic gelatino-silver-halide developing-out emulsion containing (a) a condensation product of ethylene oxide with an organic compound containing an active hydrogen atom selected from the group consisting of alcohols, phenols, amines, mercaptans, acids, amides, and hydrocarbons, said condensation product having a molecular weight of at least 300, and (b) S-thioctic acid.
• a photographic silver halide emulsion containing (a) the oleyl ether of polyethylene glycol having a molecular weight of at least 700 and (b) 5-thioctic acid.
• a photographic silver halide developing-out emulsion containing (a) a polyethylene glycol having a.
• a photographic silver halide emulsion containing (a) polyethylene glycol-bis-carboglutamic acid alkali metal salt having a molecular Weight of at least 300 and (b) S-thioctic acid.
• a photographic silver halide developing-out emulsion containing (a) 3,6,9,12,15,18,21,24-octaoxahexacosane-bis-pyridinium perchlorate and (b) S-thioctic acid.
• a sensitizer selected from the group consisting of polyalkylene glycols and condensation products of an alkylene oxide containing from 2 to 4 carbon atoms with an organic compound containing an active hydrogen atom selected from the class consisting of alcohols, phenols, amines, mercaptans, acids, amides, and hydrocarbons, said alkylene oxide polymer having a mo
• a photographic element comprising a support and coated on said support at least 2 gelatin layers, at least one of said gelatin layers containing light-sensitive silver halide, sensitized with an alkylene oxide polymer selected from the group consisting of polyalkylene glycols and condensation products of an alkylene oxide containing from 2 to 4 carbon atoms with an organic compound containing a reactive hydrogen atom selected from the class consisting of alcohols, phenols, amines, mercaptans, acids, amides, and hydrocarbons, said alkylene oxide polymer having a molecular Weight of at least 300, and at least one of said gelatin layers containing S-thioctic acid.
• an alkylene oxide polymer selected from the group consisting of polyalkylene glycols and condensation products of an alkylene oxide containing from 2 to 4 carbon atoms with an organic compound containing a reactive hydrogen atom selected from the class consisting of alcohols, phenols, amines, mercaptans, acids, amides, and hydrocarbon

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  • BE BE569317D patent/BE569317A/xx unknown
• 1957
  • 1957-07-11 US US67112957 patent/US2948614A/en not_active Expired - Lifetime
• 1958
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