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

• Thisinvention relates to photographic emulsions and more particularly to chemical sensitizers therefor.
• silver halide emulsions may be chemically sensitized with a variety of materials so as to increase the speed and generally the gamma of the emulsions as opposed to optical sensitizing in which the optical range of sensitivity is increased.
• chemical sensitization results in either the formation of silver sulfide on the surface of the silver halide crystal or results in the formation of small amounts of silver from the reduction of silver halide, which effect may be in addition to the former effect sometimes known as sulfur sensitizing.
• the present invention is concerned primarily with chemical sensitization apparently of the latter type.
• One object of our invention is to provide chemically sensitized silver halide emulsions of enhanced sensitivity. Another object is to provide novel chemical sensitizing agents for photographic emulsions. Another object is to provide hanced by means of both sulfur sensitizers and the novel sensitizers of our invention.
• a further sion layers of polyamine compounds such as diethylene triamine, triethylene tetramine or tetraethylene pentamine, tetrapropylene pentamine, and the like.
• the compounds have the general structure where n is a positive integer from'one to five, preferably one to three, and R is an alkylene chain of from two to four carbon atoms, preferably two carbon atoms.
• the three first-mentioned polyamines are particularly desirable not only because of the speed increases they eifect, but also because their synthesis is relatively simple compared to polyamines of higher molecular weight, therefore they are more readily available in a high degree of purity.
• the novel sensitizers are incorporated in the emulsions at any stage in their preparation but referably before digestion is complete. Generally, in order to obtain the optimum sensitizing effect, we heat the emulsion after addition of the sensitizing agent.
• the sensitizers may be used in conjunction with other chemical and optical sensitizers such as the well known sulfur sensitizin compounds such as disclosed in Sheppard U. S.'Patents 1,574,944, granted March 2, 1926, and 1,623,499, granted April 5, 1927.
• Our novel sensitizers may be employed before, after or simultaneously with sulfur sensitizing. Also our novel sensitizers are useful with a variety of emulsions, producing pronounced speed increases in either negative or positive types of emulsions.
• Example 1 Several cc. samples of a high speed bromoiodide positive type of emulsion, each containing silver halide obtained from 20 grams of silver nitrate andpeptized with a gelatin derivative by the process of the Lowe et a1.
• U. S. application Serial No. 768,478, filed August 13, 1947 were adjusted to a pH of 6.0 and heated for 30 minutes at 50 C. with four mg. respectively of the diethylene triamine, triethylene tetramine and tetraethylene pentamine added in aqueous solution adjusted to pH 6.0. After this, each sample was added to 400 cc. of a five per cent gelatin solution and coated on a support and dried in the usual manner.
• Example 3 depending upon the type of emulsion used, vary somewhat from the optimum amounts employed in the above examples, one-fifth to five times as much sensitizing agent producing emulsions of 40 useful sensitivity. As is apparent, less heating is usually required when the larger amounts are employed and conversely when using the smaller quantities of sensitizing agent.
• novel sensitizers since the novel sensitizers are so active, W ablbut 0? C), 500 further sensitization takes place even substan- D- y a op fll S grams tially below the neutral point when they are Sodium sulfite, desiccated, 96.0grams dd d to th l i l i grams
• the novel sensitizers may, in general, be em- Sodium car na e, de i a 4 ram ployed in .hydrophilic colloid emulsion vehicles;
• emulsions are suitn the Ina-111161 0f EXample 450 0
• Samples of 5 able to use in forniingsingle as well as multilayer the above negative type of emulsion containing film useful in color photography which custogelatin were first sulfur sensitized by heating marily include on a support two or more vemulwith a sulfur sensitizing agent at 59 C. for 20 sion layers sensitized to different regions of the minutes, then cooled to 40 C. and one or two visible spectrum .and may or may not contain mg. additions of the tetraethylene pentamine coupler compounds.
• a light-sensitive photographic emulsion comprising silver halide and a polyamine sensitizing agent having the general formula:
• R. is an alkylene chain having from 2-4 carbon atoms and n is a positive integer of from 1-5.
• a light-sensitive photographic emulsion comprising silver halide and a polyamine sensitizing agent selected from the group consisting of diethylene triamine, triethylene tetramine, tetraethylene pentamine, and their watersoluble salts of non-desensitizing acids.
• a light-sensitive photographic emulsion comprising silver halide and triethylene tetramine as a sensitizing agent.
• a light-sensitive photographic emulsion comprising silver halide and tetraethylene pentamine as a sensitizing agent.
• a light-sensitive photographic emulsion comprising silver halide and diethylene triamine as a sensitizing agent.
• a light-sensitive photographic emulsion comprising sulfur sensitized silver halide and triethylene tetramine as an additional sensitizing agent.
• a light-sensitive photographic emulsion comprising sulfur sensitized silver halide and tetraethylene pentamine as an additional sensitizing agent.
• a light-sensitive photographic emulsion comprising sulfur sensitized silver halide and diethylene triamine as an additional sensitizing agent.
• R is an alkylene chain having from 2-4 comprising sulfur-sensitized silver halide and as an additional sensitizing agent a polyamine having the general formula I-IzN (RNH) nRNHz wherein R is an alkylene chain having from 2 to 4 carbon atoms and n is a positive integer of from 1 to 5.
• R is an alkylene chain having from 2 to 4 carbon atoms and n is a positive integer of from 1 to 5.

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

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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Cited By (29)

Families Citing this family (1)

Citations (1)

• 0
  • BE BE492214D patent/BE492214A/xx unknown
• 1948
  • 1948-11-18 US US60818A patent/US2518698A/en not_active Expired - Lifetime
• 1949
  • 1949-11-17 FR FR1006813D patent/FR1006813A/fr not_active Expired
  • 1949-11-18 GB GB29569/49A patent/GB661645A/en not_active Expired

Patent Citations (1)

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