Out of the 41 niello formulas I have collected from written sources,
only 5 are without lead. Three are Pliny's---he burnishes warm
rather than fusing, so that may be a solution for you! The remaining
2 are: one from Braun-Feldwig and an almost identical one from Oppi
Untract's first book. I'm afraid my books are in storage til I move
to my new studio premises, but if you can get a hold of the first
Oppi book, perhaps he has some suggestions for you...
The formulas appear in my Orchid posting from Wed Nov 20, 2002.
Janet in Jerusalem