Patents Examined by Won H. Loite, Jr.
  • Photographic negative material with at least one layer containing a desensitized silver halide emulsion
    Patent number: 4326021
    Abstract: Photographic negative material which has at least one layer which contains a desensitized silver halide emulsion, the desensitizer used being a trinuclear heptamethinecyanine or a halogenated trinuclear tetramethinecyanine which has three identical heterocyclic ring systems, which can have different substituents and are linked to one another by three identical methine systems, which can be mesomeric, is suitable for processing in subdued daylight but nevertheless has an adequate sensitivity on exposure to intense light.
    Type: Grant
    Filed: February 11, 1981
    Date of Patent: April 20, 1982
    Assignee: Ciba Geigy AG
    Inventors: Rolf Steiger, Jean-Francois Reber