Patents by Inventor Roger Lok

Roger Lok 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).

  • Photographic recording material with improved raw stock keeping
    Patent number: 4957855
    Abstract: The raw stock keeping quality of photographic recording material is improved without loss of photographic speed. The improved keeping quality results from a combination of agents which cause speed losses when separately employed.
    Type: Grant
    Filed: September 21, 1989
    Date of Patent: September 18, 1990
    Assignee: Eastman Kodak Company
    Inventors: Gladys L. MacIntyre, Roger Lok
  • Photographic recording materials with enhanced latent image stability
    Patent number: 4948721
    Abstract: Latent image stability is enhanced in photographic recording materials using N-alkyl- or N-alkenylbenzothiazolium or -benzoselenazolium salts.
    Type: Grant
    Filed: July 26, 1989
    Date of Patent: August 14, 1990
    Assignee: Eastman Kodak Company
    Inventors: Roger Lok, Ronald E. Leone
  • Cyclic dichalcogenide fog inhibiting agents for silver halide photography
    Patent number: 4861703
    Abstract: Radiation-sensitive silver halide photographic elements are disclosed which are protected against fog by cyclic dichalcogenides. A new cyclic oxaspiro ditelluride is disclosed.
    Type: Grant
    Filed: August 15, 1988
    Date of Patent: August 29, 1989
    Assignee: Eastman Kodak Company
    Inventors: Roger Lok, Wolfgang H. H. Gunther, John P. Freeman
  • Quaternized 2,1,4-benzoxatellurazinium and 2,1,4-naphthoxatellurazinium salt derivitives
    Patent number: 4677202
    Abstract: Radiation sensitive silver halide photographic elements are disclosed which are protected from fog by quaternized aromatic oxatellurazinium salts. The aromatic oxatellurazinium salts can be initially incorporated in the photographic element as manufactured or during processing.
    Type: Grant
    Filed: August 25, 1986
    Date of Patent: June 30, 1987
    Assignee: Eastman Kodak Company
    Inventors: Rosemary Przyklek-Elling, Wolfgang H. H. Gunther, Roger Lok
  • Quaternized tellurium salt fog inhibiting agents for silver halide photography
    Patent number: 4661438
    Abstract: Radiation sensitive silver halide photographic elements are disclosed which are protected from fog by quaternized aromatic oxatellurazinium salts. The aromatic oxatellurazinium salts can be initially incorporated in the photographic element as manufactured or during processing.
    Type: Grant
    Filed: January 31, 1986
    Date of Patent: April 28, 1987
    Assignee: Eastman Kodak Company
    Inventors: Rosemary Przyklek-Elling, Wolfgang H. H. Gunther, Roger Lok
  • Divalent chalcogenide fog inhibiting agents for silver halide photography
    Patent number: 4607001
    Abstract: Radiation sensitive silver halide photographic elements are disclosed which are protected from fog by aromatic tellurochalcogenides. The aromatic tellurochalcogenides can be initially incorporated in the photographic element as manufactured or during processing.
    Type: Grant
    Filed: April 4, 1985
    Date of Patent: August 19, 1986
    Assignee: Eastman Kodak Company
    Inventors: Roger Lok, Wolfgang H. H. Gunther
  • Amido substituted divalent chalcogenide fog inhibiting agents for silver halide photography
    Patent number: 4607000
    Abstract: Radiation sensitive silver halide photographic elements are disclosed which are protected from fog by amido substituted aromatic tellurochalcogenides. The amido substituted aromatic tellurochalcogenides can be initially incorporated in the photographic element as manufactured or during processing.
    Type: Grant
    Filed: April 4, 1985
    Date of Patent: August 19, 1986
    Assignee: Eastman Kodak Company
    Inventors: Wolfgang H. H. Gunther, Roger Lok
  • Tellurium salt fog inhibiting agents for silver halide photography
    Patent number: 4581330
    Abstract: Radiation sensitive silver halide photographic elements are disclosed which are protected from fog by aromatic oxatellurazinium salts. The aromatic oxatellurazinium salts can be initially incorporated in the photographic element as manufactured or during processing.
    Type: Grant
    Filed: February 19, 1985
    Date of Patent: April 8, 1986
    Assignee: Eastman Kodak Company
    Inventors: Wolfgang H. H. Gunther, Roger Lok
  • Photographic speed increasing and latent image stabilizing compounds, silver halide emulsions, and photographic elements
    Patent number: 4451557
    Abstract: Photographic silver halide emulsions show increased speed and reduced latent image fading when a compound of the following structure is incorporated: ##STR1## wherein: X is --O--, --S--, --Se--, or ##STR2## Y.sup.1 and Y.sup.2 individually represent hydrogen or an aromatic nucleus or together represent the atoms completing a fused aromatic nucleus;Z is ##STR3## R is hydrogen or lower alkyl of from 1 to 5 carbon atoms; and R.sup.1 is hydrogen or methyl.
    Type: Grant
    Filed: February 14, 1983
    Date of Patent: May 29, 1984
    Assignee: Eastman Kodak Company
    Inventors: Roger Lok, John P. Freeman, William N. Baum
  • Photographic speed increasing and latent image stabilizing compounds, silver halide emulsions, and photographic elements
    Patent number: 4378426
    Abstract: Photographic silver halide emulsions show increased speed and reduced latent image fading when a compound of the following structure is incorporated: ##STR1## wherein: X is -O-, -S-, -Se-, or ##STR2## Y represents the atoms completing a fused aromatic nucleus; Z is ##STR3## R is hydrogen or lower alkyl of from 1 to 5 carbon atoms.
    Type: Grant
    Filed: November 12, 1981
    Date of Patent: March 29, 1983
    Assignee: Eastman Kodak Company
    Inventors: Roger Lok, John P. Freeman, William N. Baum
  • Photographic speed increasing and latent image stabilizing compounds, silver halide emulsions, and photographic elements
    Patent number: T103803
    Abstract: Photographic silver halide emulsions show increased speed and reduced latent image fading when a compound of the following structure is incorporated: ##STR1## wherein: X is --O--, --S--, --Se--, or ##STR2## Y represents the atoms completing a fused aromatic nucleus; Z is ##STR3## and R is hydrogen or lower alkyl of from 1 to 5 carbon atoms.
    Type: Grant
    Filed: August 16, 1982
    Date of Patent: January 3, 1984
    Inventors: Roger Lok, John P. Freeman, William N. Baum
  • Photographic speed increasing and latent image stabilizing compounds
    Patent number: T104903
    Abstract: Photographic silver halide emulsions show increased speed and reduced latent image fading when a compound of the following structure is incorporated: ##STR1## wherein: X is ##STR2## Y.sup.1 and Y.sup.2 individually represent hydrogen or an aromatic nucleus or together represent the atoms completing a fused aromatic nucleus;Z is ##STR3## R is hydrogen or lower alkyl of from 1 to 5 carbon atoms; and R.sup.1 is hydrogen or methyl.
    Type: Grant
    Filed: February 7, 1984
    Date of Patent: December 4, 1984
    Inventors: Roger Lok, John P. Freeman, William H. Baum