Patents by Inventor William R. Pangratz

William R. Pangratz 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).

  • Process for rapid access development of silver halide films using pyridinium as development accelerators
    Patent number: 5384232
    Abstract: A process of developing exposed silver halide elements comprises developing said element in a developer in the presence of a development accelerator compound as defined. The development accelerator compounds include pyridinium, or pyridinium and and imidazolium compounds. The process is applicable to standard and hydrazine-containing films and to hydroquinone and/or ascorbic acid-based developers. The development accelerator may be incorporated into the developer or into the silver halide emulsion.
    Type: Grant
    Filed: March 30, 1993
    Date of Patent: January 24, 1995
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Julie C. Bishop, Dominic M. Chan, Dennis S. Donald, Ludovic Fodor, William R. Pangratz, Glenn M. Russo, John R. Shock
  • High contrast continuous tone developer and process of use
    Patent number: 4172728
    Abstract: A photographic developer containing hydroquinone, an auxiliary developer such as phenidone, and high sulfite is formulated using an organic base such as diethanolamine. This is useful for processing litho film in rapid access machine processors to produce high contrast line and half-tone dot images from films processed therein.
    Type: Grant
    Filed: December 16, 1977
    Date of Patent: October 30, 1979
    Assignee: E. I. Du Pont de Nemours and Company
    Inventors: Joseph A. Sincius, William R. Pangratz