Granted Patent
Utility
US 4,879,203 · App. 07/177,344
Process for producing masked positive color images by the silver dye bleach process
Inventor:
Urs Furholz
Patented Case
View Patent ↗
Granted: Nov 7, 1989
Filed: Apr 4, 1988
Inventor
Urs Furholz
Assignee (at issue)
Ciba-Geigy
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.