Granted Patent
Utility
US 4,753,869 · App. 06/935,098
Photographic developing agents containing stable, soluble, pyrazolidinones
Inventors:
William E. Long, Malcolm D. Tirel, Monica H. Gent, Terence C. Webb
Patented Case
View Patent ↗
Granted: Jun 28, 1988
Filed: Nov 24, 1986
Inventors
William E. Long
Malcolm D. Tirel
Monica H. Gent
Terence C. Webb
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.