Patents by Inventor Raymond J. LeStrange

Raymond J. LeStrange 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 elements with improved speed and low fog
    Patent number: 5192655
    Abstract: Substituted diaminedithio-containing compounds useful for improving the speed of a silver halide emulsion are described. These compounds can be added in small amounts to the emulsion preferably after the emulsion has been chemically sensitized and just prior to coating. Fog levels are not greatly affected which is surprising since conventional sensitizers generally do increase the fog level.
    Type: Grant
    Filed: July 5, 1991
    Date of Patent: March 9, 1993
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Dominic M. Chan, Raymond J. LeStrange
  • Blue spectral sensitizers for non-tabular silver halide elements
    Patent number: 5102781
    Abstract: Zeromethine blue spectral sensitizing dyes have found utility in emulsions made without tabular grains. These emulsions are particularly useful for exposure to a light source rich in blue emission and are especially useful in radiographic elements designed for exposure to intensifying screens having such emission.
    Type: Grant
    Filed: July 9, 1990
    Date of Patent: April 7, 1992
    Assignee: E. I. du Pont de Nemours and Company
    Inventors: Dietrich M. Fabricius, Raymond J. LeStrange
  • Photographic film with improved speed to fog ratio
    Patent number: 5102782
    Abstract: Photographic, gelatino, silver halide emulsions exhibiting improved speed/fog ratio and good hardening are described. These emulsions are made by sensitizing with 1-naphthol-4-sulfonic acid and by adding an aliphatic polyol thereto.
    Type: Grant
    Filed: December 11, 1990
    Date of Patent: April 7, 1992
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Raymond J. LeStrange
  • Silver halide emulsions with improved speed
    Patent number: 4965184
    Abstract: Photographic, silver halide emulsions can be additionally sensitized without a deleterious increase in fog, by the addition of an alkali metal salt of 1-napthol-4-sulfonic acid. These emulsions are stable, and have good contrast and top density. The 1-napthol-4-sulfonic acid can be added conveniently from an aqueous solution and is totally compatible with conventional silver halide elements.
    Type: Grant
    Filed: February 23, 1989
    Date of Patent: October 23, 1990
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Raymond J. LeStrange
  • Elimination of defects in cysteine-sensitized emulsions
    Patent number: 4514492
    Abstract: Desensitization defects due to nonferrous metal contamination of a silver halide film sensitized by a cysteine-thiazolidine moiety are decreased by incorporating a chelating agent such as quinaldic or picolinic acid into one or more layers of the film.
    Type: Grant
    Filed: December 15, 1983
    Date of Patent: April 30, 1985
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Raymond J. LeStrange, John H. Bayless, Jr., Allan R. Schoenberg
  • Silver halide emulsion containing a purified cysteine-glutaraldehyde polymer fraction and process of making
    Patent number: 4481359
    Abstract: From the complex reaction mixture of cysteine and glutaraldehyde a low molecular weight polymer is recovered for use as an additive to silver halide emulsions and developers to increase speed. Iron and nickel complexes of the purified low molecular weight polymer are similarly useful for silver halide emulsions.
    Type: Grant
    Filed: January 4, 1982
    Date of Patent: November 6, 1984
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Jacob Beutel, Raymond J. LeStrange
  • Process for sensitizing photographic silver halide emulsions
    Patent number: 4175970
    Abstract: A process for sensitizing photographic gelatino-silver halide emulsions with glutaraldehyde bisulfite in combination with benzene sulfinic acid.
    Type: Grant
    Filed: July 24, 1978
    Date of Patent: November 27, 1979
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Raymond J. LeStrange