Patents by Inventor Marcel Jan Libeer

Marcel Jan Libeer 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).

  • Method of preparing photographic silver halide emulsions
    Patent number: 3957490
    Abstract: Silver halide emulsions are prepared by silver halide precipitation in the presence of a reducing agent, physical ripening and, if desired, chemical ripening wherein subsequent to the addition of reducing agent and before the grains have reached their final size an oxidizing agent is added to the emulsion. By means of the reducing and oxidizing agents, the gradation and photosensitivity characteristics of the emulsion can be controlled at will.
    Type: Grant
    Filed: April 25, 1974
    Date of Patent: May 18, 1976
    Assignee: AGFA-GEVAERT N.V.
    Inventors: Marcel Jan Libeer, Frans Henri Claes
  • Methine dyes
    Patent number: 3931156
    Abstract: The invention relates to a new class of pyrrolobenzimidazole, benzimidazoloisoquinoline and dipyrodinobenzodiimidazole in cyanine sensitizing dyes derived therefrom and their use in silver halide emulsions, and to methods for preparation of such new dyes.
    Type: Grant
    Filed: April 30, 1973
    Date of Patent: January 6, 1976
    Assignee: Agfa-Gevaert N.V.
    Inventors: Marcel Jan Libeer, Henri Depoorter, Gerrit Godfried Van Mierlo, Raymond Gerard Lemahieu