Hi Julia. Precision Etchings and Findings in Warwick, RI.
401-738-5093 and Photofabrication Engineering in Milford, MA
508-478-2025 both used to do silver etching. I have worked with
Chemart, who used to be just base metals, but that was some time
ago. They’re at 401-333-9200.
My best resource for this sort of stuff was the Providence area
Yellow Pages. They may have it at the public library or on line.
If you have any questions about this, give me a call.