Patents by Inventor Oskar Riester

Oskar Riester 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).

  • Antihalation and filter dyes for photographic materials
    Patent number: 3984246
    Abstract: Photographic materials containing in at least one photographic layer as antihalation- or filter-dyes mono-, tri- or pentamethineoxonoles of 1-sulfolanyl pyrazolones, which dyes can be easily decolorized and washed out on treatment of the photographic material in photographic processing.
    Type: Grant
    Filed: November 4, 1975
    Date of Patent: October 5, 1976
    Assignee: AGFA-Gevaert, A.G.
    Inventors: Hans Ohlschlager, Oskar Riester, Franz Moll
  • Light-sensitive photographic material containing a supersensitized silver halide emulsion layer
    Patent number: 3954481
    Abstract: Sensitization of silver halide emulsions by merocyanines and cationic cyanines and the stability of this sensitization is improved by addition of heterocyclically substituted thioureas of the formula ##EQU1## wherein R.sup.1 is alkyl, alkenyl or arylR.sup.2 is alkyl, cycloalkyl or aryln is 0 or 1, andZ completes a 5- or 6-membered heterocyclic group, preferably one which also contains a sulfur atom.
    Type: Grant
    Filed: September 24, 1974
    Date of Patent: May 4, 1976
    Assignee: AGFA-Gevaert, A.G.
    Inventors: Hans Ohlschlager, Oskar Riester