Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D257/00—Heterocyclic compounds containing rings having four nitrogen atoms as the only ring hetero atoms
  • C07D257/02—Heterocyclic compounds containing rings having four nitrogen atoms as the only ring hetero atoms not condensed with other rings
  • C07D257/04—Five-membered rings
• • 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

• ABSTRACT OF THE DESCLOSURE Stabilizer and antifogging compounds for use in silver halide photography include dehydrodithizone and chloride, bromide and iodide salts for S-alkyl m.ercapto-2,3- diaryltetrazole, 5-alkyl-mercapto-2,3 dialkyltetrazole, 5-carboXyalkylmercapto-2,3-diaryltetrazole and 5-carboxyalkylmercapto-Z,3-dialkyltetrazole compounds.
• This invention relates in general tophotography and in particular to the provision of novel stabilizing compounds for use in connection with the preparation and/ or processing of photographic silver halide emulsions.
• fog As used in the photographic art connotes that portion of the density obtained upon development which arises by virtue of factors other than the photographic exposure.
• the fog may be attributable to a number of influences including for example, excessive ripening of the emulsion, prolonged storage of the film and especially under conditions of elevated temperature and/ or humidity, as well as by prolonged development of the exposed emulsion and the like.
• the fog may be of two types, namely, yellow fog and chemical (gray) fog.
• the yellow fog sometimes referred to as colored or dichroic fog, is essentially a colloidal deposit of silver, the color intensity and general appearance of which are determined by the minute particle size and degree of subdivision.
• the fog is chiefly yellow in color and is most apparent in the lighter portions of the negative. The color may vary, however, and the colloidal silver particles may, for example, appear green by reflected light and yellow or red by transmitted light.
• the so-called chemical fog or gray fog
• such fog may be caused by the nucleation of silver on or in the silver halide grains due to inadvertent exposure, excessive ripening of the emulsion, storage of the film under severe conditions of temperature and/or humidity, etc.
• Fog may also be caused by exposure to chemicals, for example, hydrogen sulfide and other reactive sulphur compounds, hydrogen peroxide vapors and strongly reducing materials such as those present in the developer solution.
• the fog will usually manifest itself as a spurious density extant over the entire area of the sensitive coating and typically, is substantially nonuniform.
• the antifogging and stabilization characteristics of light-sensitive silver halide emulsions can be synergistically modified to advantage by the utilization of a particular class of chemical compounds in connection with the preparation and/or processing of such emulsions.
• a primary object of the present invention resides in the provision of improved antifogging and stabilizer compounds in which the foregoing and related disadvantages are eliminated or at least mitigated to a substantial degree.
• Another object of the present invention resides in the provision of light-sensitive silver halide emulsions containing a compound which stabilizes the emulsion against fogging while exhibiting little, if any, tendency to reduce the speed or contrast of such emulsions.
• a further object of the present invention resides in the provision of light-sensitive silver halide emulsions and photographic elements prepared therewith containing an antifogging compound which is substantially devoid of any tendency to reduce the sensitivity of the emulsion to light of longer wave length due to the presence of one or more sensiizing dyes.
• a still further object of the present invention resides in the provision of a process for the treatment of an exposed photographic silver halide emulsion wherein at least one of the steps of pretreating or developing the emulsion is effected in the presence of a novel stabilizing compound to be more fully described hereinafter.
• a light-sensitive photographic element e.g., silver halide emulsion
• developing solution and/or pretreatment solution of a compound selected from the group consisting of (a) S-alkylmercapto-Z,3-diaryltetrazolium salts, (b) 5-alkylmercapto-Z,3-dialkyltetrazolium salts, (c) 5-carboxyalkylmercapto-Z,3-diaryltetrazolium salts, (d) S-carboxyalkylmercapto-Z,3-dialkyltetrazolium salts and (e) dehydrodithizone.
• R, R and R represent alkyl, e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, hexyl, undecyl, dodecyl, etc., and preferably lower alkyl of 1 to 4 carbon atoms; aryl, e.
• R represents lower alkylene, branch or straight chained, substituted or unsubstituted, e.g., methylene, ethylene, isobutylene, etc.
• X represents an anion such as a halide atom, e.g., chloride, bromide or iodide
• M represents hydrogen or a watersolubilizing cation such as alkali metal, e.g., sodium, potassium, etc.; ammonium, substituted ammonium, etc.
• dehydrodithizone as reported in the literature is capable of several formulistic definitions. In this connection specific reference is made to J.A.C.S., vol. 83, p. 5023. Despite the fact that several theories are postulated in explanation of the validity of a given structural representation, it is nevertheless manifest that the term dehydrodithizone connotes a specific species of tetrazolium salts.
• ripening finals are added during the ripening or sensitivity increasing stage of the emulsion making process. Such additions may be effected before, during or after the decomposition of the soluble silver salt such as silver nitrate by means of a soluble halide such as potassium bromide, sodium chloride or the like in the presence of a suitable colloid carrier such as gelatin, polyvinyl alcohol, solubilized casein albumen or the like.
• a suitable colloid carrier such as gelatin, polyvinyl alcohol, solubilized casein albumen or the like.
• Coating finals are added to the emulsion just prior to coating on a suitable support such as glass, paper or film at a time when the emulsion has nearly attained its maximum sensitivity.
• novel stabilizers of the present invention may be incorporated in a layer adjacent to the sensitized layer such as an anti-abrasion layer.
• the stabilizing compound may be utilized in concentrations varying over a relatively wide range; for example, when added to the light-sensitive silver halide emulsion layer as a ripening final, it is found that optimum realization of results provided herein are assured with stabilizer concentrations ranging from as low as .02 milligram up to about 500 milligrams per 0.6 mole of silver halide.
• the concentration selected within the aforestated range will depend to a large extent on the type of emulsion employed and thus it is advisable to determine the optimum concentration from case to case. If added during the emulsion preparation stage, stabilizer concentrations on the order of approximately one-tenth of those employed when adding the stabilizer as a coating final are found to be quite suitable.
• the stabilizer compounds contemplated herein can be applied in a variety of ways to impart stability to photographic elements. As previously mentioned, they may be included as a constituent of the emulsion layer, of a surface layer over the emulsion or alternatively, over the base or support.
• inventions of the present invention contemplate the addition of such compounds to at least one of the developing, fixing, washing, drying, etc. solutions utilized in the processing of the exposed emulsion.
• the stabilizer when utilized in the Washing step the stabilizer can be applied to the otherwise finished photographic element by immersing same in an alcohol, e.g., methanol or alcohol-water solution in the case of the free acid derivatives while the salt derivatives may be employed effectively as simple water solutions.
• the improvements provided by the present invention are particularly manifest according to procedures whereby development is effected in the presence of said stabilizer compounds.
• This would be the case should the stabilizer be included in the light-sensitive photographic element, the developing solution and/or suitable developer pre-bath.
• the stabilizers of the present invention are preferably employed in concentrations ranging from about 1 to about 50 milligrams per liter of solution, with a range of about 5 milligrams to about 20 milligrams per liter being particularly preferred.
• the stabilizers may also be used in non-sensitized emulsions, X-ray emulsions, paper emulsions, color emulsions and the like. If used with sensitizing dyes, they may be added'to the emulsion before or after dye addition. Moreover, the present stabilizers may also be employed in conjunction with other known antifoggants and stabilizers, reduction stabilizers, metal and noble metal sensitizers or in combination with other additive agents and the like.
• the stabilizer may also be employed in gelatin or other water-permeable colloids including polyamides or a mixture of gelatin with a polyamide as described in U.S. Patent 2,289,775; polyvinyl alcohol and gelling compound as described in U.S. Patent 2,249,537; polyvinyl acetaldehyde acetal resins and partially hydrolyzed acetate resins described in U.S. Patents 1,939,422 and 2,036,092; cellulose derivatives, e.g., cellulose nitrate, cellulose acetate, and the lower fatty acid esters of cellulose including sample and mixed esters and ethers of cellulose and the like.
• polyamides or a mixture of gelatin with a polyamide as described in U.S. Patent 2,289,775
• polyvinyl alcohol and gelling compound as described in U.S. Patent 2,249,537
• a solution of the stabilizer in a suitable solvent such as water, alcohol, dimethyl formamide or alcohol-water mixture adjusted to a neutral or slightly alkaline pH, i.e. about 7.5 to 10, is made up and the solution mixed with the emulsion at any convenient stage during its preparation, but preferably during ripening or just prior to coating.
• any of the aforedescribed compounds may be utilized to advantage in the practice of the present invention, particularly beneficial results are obtained and especially with regard to the suppression of fog which would otherwise result from film storage under severe conditions of humidity and temperature with the 1,3-diphenyl derivatives.
• such compounds there may be mentioned without limitation the following:
• a silver halide emulsion in gelatin containing 2% silver iodide and 98% silver bromide is prepared in conventional manner and brought up to its maximum light sensitivity. It is then readied for coating; finals are added such as sensitizing dyes and hardening agents. Approximately 6 cc. of a 0.01% solution of S-methylmercapto- 2,3-diphenyltetrazolium iodide was added to the emulsion as an antifoggant and stabilizer. The emulsion samples contained about 0.6 mole of silver halide. The so prepared emulsion samples were then coated on a suitable cellulose ester base and dried. Samples of these film coatings were then exposed in a Type IB sensitometer and developed in a developer of the following composition:
• the developer composition may be any of those conventionally employed in the development of exposed silver halide emulsions and accordingly, may be of the hydroquinone type, i.e., those which contain hydroquinone, potassium meta'bisulfite and potassium bromide, or they may be of the metol-hydroquinone type, i.e., those which contain p-methylaminophenol, sodium sulfite, sodium bisulfite, hydroquinone sodium carbonate, and potassium bromide.
• the developer composition may be of the so-called borax type, i.e., those which contain p-methylaminophenol, sodium sulfite, hydroquinone borax and potassium bromide.
• novel stabilizers of the present invention may be employed singly or in admixtures comprising two or more of such compounds. Again, optimum combinations thereof can be readily ascertained in a particular instance by routine laboratory experimentation.
• a process of treating an exposed silver halide emulsion which comprises developing said emulsion in the presence of an antifoggant and stabilizer comprising a compound selected from the group consisting of (a) dehydrodithizone, (b) 5-alkylmercapto-2,3-diaryltetrazoliurn chlorides, bromides and iodides, (c) S-alkylmercapto- 2,3-dialkyltetrazolium chlorides, bromides and iodides, (d) S-carboxyalkylmercapto-2,3-diaryltetrazolium chlorides, bromides and iodides, (e) S-carboxyalkylmercapto- 2,3-dialkyltetrazolium chlorides, bromides and iodides and (f) the alkali metal, ammonium and substituted ammonium salts of the carboxy compounds of (d) and (e).
• said antifoggant and stabilizer compound comprises S-methylmercapto-2,3-diphenyltetrazolium iodide.
• a process according to claim 1 wherein said antifoggant and stabilizer compound comprises dehydrodithizone.
• An aqueous developer solution containing a silver halide photographic developing agent and an antifoggant and stabilizer comprising a compound selected from the group consisting of (a) dehydrodithizone, (b) 5-alkylmercapto-2,3 -diaryltetrazolium chlorides, bromides and iodides, (c) 5-alkylrnercapto-2,3-dialky1tetrazolium chlorides, bromides and iodides, (d) S-carboxyalkylmercapto- 2,3-diaryltetrazolium chlorides, bromides and iodides, (e) 5-carboxyalkylmercapto-Z,3-dia1kyltetrazolium chlorides, bromides and iodides and (f) the alkali metal, ammonium and substituted ammonium salts of the carboxy compounds of (d) and (e).
• a light-sensitive silver halide emulsion containing an antifoggant and stabilizer comprising a compound selected from the group consisting of (a) dehydrodithizone, (b) 5-alkylmercapto-Z,3-diaryltetrazolium chlorides, bromides and iodides, (c) 5-alky1mercapto-2,3-dialkyltetrazolium chlorides, bromides and iodides, (d) S-carboxyalkylmercapto 2,3 diaryltetrazolium chlorides, bromides and iodides, (e) 5-carboxyalkylmercapt0-2,3-dialkyltetrazolium chlorides, bromides and iodides and (f) the alkali metal, ammonium and substituted ammonium salts of the carboxy compounds of (d) and (e).
• a light-sensitive photographic material comprising a base and a light-sensitive silver halide emulsion, said lightsensitive material containing an antifoggant and stabilizer comprising a compound selected from the group consisting of (a) dehydrodithizone, (b) 5-alkylmer capto-2,3-diaryltetrazolium chlorides, bromides and iodides, (c) 5-alkylmercapto-2,3-dialkyltetrazolium chlorides, bromides and iodides, (d) S-carboxyalkylrnercapto-2,3-diaryltetrazolium chlorides, bromides and iodides, (e) 5-carboXya1kylmercapto-2,3-dialkyltetrazolium chlorides, bromides and iodides and (f) the alkali metal, ammonium and substituted ammonium salts of the carboxy compounds of (d) and (e).

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
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• 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)
• Investigating Or Analysing Biological Materials (AREA)

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Cited By (7)

Citations (4)

• 1966
  • 1966-01-03 US US517976A patent/US3420664A/en not_active Expired - Lifetime
  • 1966-12-20 GB GB56895/66A patent/GB1174907A/en not_active Expired
  • 1966-12-21 DE DE19661547920 patent/DE1547920A1/de active Pending
  • 1966-12-29 BE BE691942D patent/BE691942A/xx unknown
  • 1966-12-30 FR FR89652A patent/FR1507069A/fr not_active Expired

Patent Citations (4)

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