I'll get to that soon but a number of Italian and several German manufacturers used Arco type celluloids. Of the type used by Omas, MontBlanc comes to mind. I don't think MB used the bronze arco pattern but they used the platinum arco on many of their pens as well as a red arco pattern.
When I get back tonight, I'll put up a new pen, one in platinum celluloid.
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