Patents by Inventor Joseph D. Overman

Joseph D. Overman has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Silver halide antifoggants based on quinoxaline derivatives and related heterocycles
    Patent number: 4463088
    Abstract: A group of heterocyclic antifoggants based on quinoxaline is useful in very high speed gelatino-silver halide emulsions.
    Type: Grant
    Filed: July 5, 1983
    Date of Patent: July 31, 1984
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Joseph D. Overman
  • Benzothiazoline derivatives as silver halide antifoggants
    Patent number: 4416981
    Abstract: Substituted benzothiazolines are used as antifoggants in high speed silver halide emulsions.
    Type: Grant
    Filed: April 29, 1982
    Date of Patent: November 22, 1983
    Assignee: E. I. Du Pont de Nemours & Co.
    Inventor: Joseph D. Overman
  • Speed-increasing adjuvants for silver halide emulsions
    Patent number: 4396711
    Abstract: Derivatives of thiazolidine are used in photographic silver halide emulsions to increase their speed 40% or more with little or no increase in emulsion fog. Lower silver halide coating weights are thus possible.
    Type: Grant
    Filed: March 29, 1982
    Date of Patent: August 2, 1983
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Joseph D. Overman
  • Organic halogen compounds for negative-working silver halide emulsions
    Patent number: 4323645
    Abstract: Small amounts of specific organic halogen compounds added to medical X-ray emulsions (ex. 2-chloro-4-nitrobenzyl chloride, 2,2,2-trichloroethanol and m-nitrobenzyl chloride) give significantly reduced fog levels accompanied by little or no speed loss.
    Type: Grant
    Filed: August 1, 1980
    Date of Patent: April 6, 1982
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Laurence W. Hall, Joseph D. Overman
  • Silver halide development accelerators
    Patent number: 4292391
    Abstract: Pyrazolo [3,4-d] pyrimidine, and derivatives thereof, can be added to either a silver halide emulsion, or to a hydroquinone (litho) developer to accelerate development and reduce the induction period.
    Type: Grant
    Filed: February 6, 1980
    Date of Patent: September 29, 1981
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Joseph D. Overman
  • Formation of silver halide grains in the presence of thioureas
    Patent number: 4221863
    Abstract: A silver halide emulsion which is useful in photography is described. The silver halide grains are characterized by uniform and increased grain size and uniform crystal habit when a compound containing the .dbd.N--C(.dbd.S)--N.dbd. moiety is present during the formation of the grains in the precipitation and/or the ripening steps.
    Type: Grant
    Filed: March 31, 1978
    Date of Patent: September 9, 1980
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Joseph D. Overman, Joseph J. Sheeto, Jr.