Granted Patent
Utility
US 4,496,432 · App. 06/508,382
Electrolytic methods for enhancing contrast between metallic surfaces
Inventor:
Delbert A. Nauman
Patented Case
View Patent ↗
Granted: Jan 29, 1985
Filed: Jun 27, 1983
Inventor
Delbert A. Nauman
Assignee (at issue)
AT&T Technologies Incorporated
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.