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 more particularly to photographic emulsions of the silver halide type.
• the speed of gelatino- -silver-halide emulsions can be enhanced by an extended digestion or ripening of the emulsion. It is also known that the speed of silver halide emulsions (spectrally sensitized or not) can vbe enhanced by incorporating in the emulsions compounds containing a divalent atom of the sulfur group directly joined by a double bond to a single metalloid atom to which is attached at least another group of atoms. Examples of such compounds are allyl isothiocyanate and allylthiourea. s
• the supersensitizing effect is confined more or less to a single spectral region, the supersensiti'zation attained in our new emulsions extends throughout the entire region in which the spectral sensitizer acts (and is fairly uniform in degree throughout the entire region), while at the same time the sensitivity in the violet and blue region (where the spectral sensitizer does not act) is also enhanced about to the same degree.
• a suitable solvent such as water or methyl alcohol.
• the surface-active substance should be thoroughly incorporated in the emulsion.
• surface active substance 'can be added to the I finished emulsion or at any stage of the preparation of the emulsion.
• the surface-active substance can be incorporated in the emulsion before, simultaneously with, or'
• sensitizing dye before incorporating the surface-active substance.
• the methods of incorporating sensitizing dyes in emulsions are, of course, well known to those skilled in the art. Ordinarily, it is advantageous to employ a solution of the sensitizing dye in a suitable solvent, e. g. methyl alcohol. Ethyl alcohol or acetone may be employed in cases where the ,solubility of the sensitizing dye in methyl alcohol is very low, or any other suitable solvent or other procedure may be used.
• a suitable solvent e. g. methyl alcohol.
• Ethyl alcohol or acetone may be employed in cases where the ,solubility of the sensitizing dye in methyl alcohol is very low, or any other suitable solvent or other procedure may be used.
• sensitizing dyes are ordinarily incorporated inthe washed, finished emulsions. and in accordance with our invention, the surface-active substances are advantageously also incorporated in q the washed, finished emulsions.
• the surface-active substances are advantageously also incorporated in q the washed, finished emulsions.
• surface-active substances can-be added to the emulsion during the preparation thereof, 1. e..
• the phosphonium cation should advantageously contain at least seven, eight or more members.
• such members are from the group consisting of carbon, oxygen, nitrogen and sulfur atoms.
• One or more aromatic rings such as a benzene ring, for example, can take the place of on or more of the weight or more atoms.
• a benzene ring can take the place of one atom, while a naphthalene ring (two benzene rings fused together) can take the place of two atoms.
• the atoms attached to the eight or more atoms in the chain can be hydrogen, oxygen, sulfur, carbon or halogen, for example. Any aromatic ring system in the chain can carry simple substituents.
• cationic phosphonium salt surface-active substances having a phosphonium cation containing a lipophylic organic group which contains a chain composed of from nine to twelve members selected from the group consisting of carbon atoms, oxygen atoms, sulfur atoms and aromatic ring system are advantageously employed.
• the quantity of surface-active substance which is most advantageously employed varies with the nature of the surface-active substance and with the nature of the emulsion. Ordinarily, the most advantageous concentration was found to be between about 20 mg. and about 200 mg. of the surface-active substance per gram-mole of silver halide in the emulsion, although greater or smaller concentrations. can be employed. We have found that excesses of the surface-active substance are advantageously avoided, since excesses'produce fog in the emulsions; For surface-active substances containing a lipophylic group containing a chain of eight to ten memben, we have found-thatas *much'asabout 400 mg. of surface-active substance per gram-mole of silver halide in the emulsion can ordinarily be employed without encountering excessive fog,
• the method of determining sensitivity of comprises coating the emulsion onto a glass plate to a suitable thickness and drying the coated emulsion and then testing the resulting photographic plate in a wedge spectrograph and a sensitometer, whereby spectral sensitivity and speed of the emulsion on the plate is determined.
• the spectral sensitizers are advantageously employed in about their optimum concentration, which ordinarily lies between about 3 mg. and mg. of spectral sensitizer'per liter of emulsion containing about 0.25 grammole of silver halide, although concentrations above or below the optimum concentration can be employed.
• the ratio of concentration of sensitizing dye to the. concentration of silver halide in the emulsion is advantageously larger than in the coarser grain emulsions where,
• non-acidic sensitizing dyes we include all the knownneutral and basic. sensitizing dyes: ii those sensitizing dyes which do notg'ive" colored anions. Some of these non-acidic sensitizingjjdyes,--such'as the cyanine dyes, give colored cations. "Exemplary of the non-acidic sensitizing dyes are the sensitizing cyanlne cl'yes (see, for example, United States I Patents 1,846,300, 1,846,301, 1,846,302,-1,846,303
• sensitizing dyes usually give optimum sensitization.
• concentration, as-above referred to, ofa sensitizing dye i. e. the concentration at which greatest sensitivity occurs
• concentration at which greatest sensitivity occurs can be readily determined inamanner well known to those skilled in the. art by measuring the sensitivity of a series of emulsions containing different concentrations of the sensitizing dye.
• Our invention is directed particularly to the silver halide developing-out emulsions customarily employed in the art, including the gelatinosilver-chloride, the gelatino-silver-bromide and 'the gelatino-silver-bromiodide' developing-out emulsions, for example.
• our invention can be employed with silver halide emulsions wherein the carrier is other than gelatin, for example, a resinous or cellulosic. derivative substance which has substantially no deleterious effect on the light-sensitive materials in the emulsions.
• sensitizing dyes such as Congored,whicl'1 disperse in water to give a colored anion, i. e. acidic sensitizing dyes
• a colored anion i. e. acidic sensitizing dyes
• Various other phosphonium compounds could f g con a g an l g' of be incorporated in a similar manner, as for exg 3 8 .f e ample n-lauryltriethylphosphonium perchlorate, oxyme y c or e and 6 mm um warme to n-decyltriethylphosphonium p-toluen'esulfonate remove etherand then heated under reflux for or tetramethylene bis phosphonium perchloram 3 hours at 120 By treating the product with In all instances, our novel treatment of photoacetone and ether there .was obtained.
• the photographic material may be added in var- It will be. observed from the disclosure in the ious ways, various amounts, in the presence of table that both sensitized and unsensitized photodye sensitizers, or otherwise. However, for a graphic emulsions were treated.
• a photographic silver halide emulsion sensitized with a cationic surface-active quaternary phosphonium salt is provided.
• a photographic silver halide developing-out emulsion sensitized with a cationic surface-active quaternary phosphonium salt 7.
• a photographic gelatino-silver-halide emulsion sensitized with a cationic surface-active quaternary phosphonium salt 8.
• a photographic gelatino-silver-halide developing-out emulsion sensitized with a cationic surface-active quaternary phosphonium salt 9.
• oxygen atoms oxygen atoms, nitrogen atoms and benzene nuclei.

Landscapes

• 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)
• Compositions Of Macromolecular Compounds (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23251219

Family Applications (1)

Country Status (3)

Cited By (12)

Families Citing this family (2)

• 1940
  • 1940-02-29 US US321593A patent/US2271622A/en not_active Expired - Lifetime
• 1942
  • 1942-01-07 GB GB270/42A patent/GB556458A/en not_active Expired
• 1945
  • 1945-08-11 FR FR949229D patent/FR949229A/fr not_active Expired

Also Published As

Similar Documents