Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5985509 | Photographic high contrast silver halide material | Roger H. Piggin | 1999-11-16 |
| 5736295 | Photographic high contrast silver halide material | Roger H. Piggin | 1998-04-07 |
| 5589318 | High contrast photographic silver halide material | Roger H. Piggin, Richard A. Hallett, Paul R. McIntyre | 1996-12-31 |
| 5512415 | High contrast photographic silver halide material | Roger H. Piggin, Michael B. Ledger, David Beaumond | 1996-04-30 |