Patents by Inventor Heinrich Schaller

Heinrich Schaller 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 material for the silver dye bleach process
    Patent number: 4576885
    Abstract: A photographic silver dye bleach material which contains a compound of the formula ##STR1## in which R is a substituted alkyl, R.sub.1 is substituted or unsubstituted alkyl, p is 1 or 2, q is 0 or 1, p+q having to be 1 or 2, and n is 1 to 20, or a salt of this compound.The benzoquinones used deactivate bleach catalysts which diffuse beyond the silver image area produced by development of the exposed material. The silver dye bleach material containing these compounds is therefore distinguished by high contrast, high sharpness and good color reproduction.
    Type: Grant
    Filed: January 16, 1984
    Date of Patent: March 18, 1986
    Assignee: Ciba-Geigy AG
    Inventors: Mario Fryberg, Heinrich Schaller, Rolf Steiger, Heinz Peter