摘要:
A process for preparing an ultrathin high bromide {111} tabular grain silver halide emulsion in a reaction vessel comprising the steps of (a) forming in the presence of a dispersing medium a population of silver halide grain nuclei containing twin planes, and (b) growing the silver halide grain nuclei containing twin planes to form high bromide {111} tabular silver halide grains by the addition of silver and halide ions, WHEREIN the majority of the silver added during growth step (b) is added at a pBr of less than 2.6 and in the presence of a triaminopyrimidine grain growth modifier containing mutually independent 4, 5 and 6 ring position amino substituents, the 4 and 6 ring position substituents being hydroamino substituents. High bromide ultrathin {111} tabular grain emulsions prepared by the process of the invention provide thinner tabular grains than that obtained in the absence of the triaminopyrimidine grain growth modifier. Additionally, the double jet process of the invention is highly controllable and commercially scalable.
摘要:
The method for preparing high grade gelatin with a specific methionine content and with reduced methionine variability from batch to batch and within a single extraction includes controlling the amount of and variability of oxidant present during processing of bone stock into gelatin. Such controls include control of oxidant concentration and range in process water, control of volume of process water used in gelatin-making process and restriction of the range of gelatin extracts used in the product gelatin. Once the aim level of oxidant has been set, the total range of oxidant around the set point should be less than 220 meq per 100 kg dry bone.
摘要:
Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains containing greater than 50 mole percent chloride and less than 5 mole percent iodide, based on total silver, with any residual halide being bromide, said grains exhibiting a face centered cubic crystal lattice structure formed in the presence of a hexacoordination complex of rhenium, ruthenium, or osmium with at least four cyanide ligands. The emulsions exhibit increased sensitivity.
摘要:
A process for preparing a thin tabular grain silver halide emulsion comprised of silver halide grains which have a halide content of at least 50 mole percent bromide, wherein tabular grains of less than 0.15 micrometers in thickness and having an aspect ratio of greater than 8 account for greater than 50 percent of the total grain projected area, comprises the steps of nucleating the silver halide grains with a gelatino-peptizer or with the use of certain synthetic polymers that serve as effective nucleation peptizers and then growing the silver halide grains with the use of either a gelatino-peptizer or certain synthetic polymers that serve as effective growth peptizers.
摘要:
Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure internally containing a nitrosyl or thionitrosyl coordination ligand and a transition metal chosen from groups 5 to 10 inclusive of the periodic table of elements.
摘要:
A photographic element which comprises a support bearing: (i) a first radiation-sensitive silver halide emulsion image-forming layer comprising a high bromide tabular grain emulsion including tabular grains having {111} major faces, exhibiting an average thickness of at least 0.07 &mgr;m and an average aspect ratio of at least 2; and (ii) a second radiation-sensitive silver halide emulsion image-forming layer comprising an ultrathin tabular grain emulsion including tabular grains having {111} major faces, containing greater than 70 mole percent bromide and at least 0.25 mole percent iodide, exhibiting an average thickness of less than 0.07 &mgr;m and an average equivalent circular diameter of at least 0.7 &mgr;m, and having latent image forming chemical sensitization sites on the surfaces of the tabular grains; wherein the surface chemical sensitization sites include epitaxially deposited silver halide protrusions containing an actual chloride concentration of from 20-50 mole %, based on epitaxially deposited silver, the chloride concentration being at least 10 mole percent higher than that of the tabular grains, and containing an actual iodide concentration of from 1 to 7 mole %, based on epitaxially deposited silver.
摘要:
Certain synthetically prepared biopolymers are useful as peptizers in the preparation of photographic silver halide emulsions and elements. Such materials can be used as either nucleation or growth peptizers in place of common peptizing colloids, such as gelatins. The biopolymers can be prepared using recombinant or chemical synthetic methods and designed to have a particular affinity (either high or low) for silver ions. Thus, they can be used to control silver halide grain morphology in the emulsions.
摘要:
A process for preparing a thin tabular grain silver halide emulsion comprised of silver halide grains which have a halide content of at least 50 mole percent bromide, wherein tabular grains of less than 0.15 micrometers in thickness and having an aspect ratio of greater than 8 account for greater than 50 percent of the total grain projected area, comprises the steps of nucleating the silver halide grains with a gelatino-peptizer or with the use of certain synthetic polymers that serve as effective nucleation peptizers and then growing the silver halide grains with the use of either a gelatino-peptizer or certain synthetic polymers that serve as effective growth peptizers.