The Ganoksin Project has announced that it will release of more than 40 digitized versions of rare antique metalsmithing and jewelry books. The books are available in PDF format for a minimal fee which will be used to support the project.
From the website:
These books cover special techniques in depth like chasing, repousse, engraving, niello making, Japanese chiseling, soldering, construction, patination and metal coloring, silversmithing and more. There are many recipes for alloys and metal surface treatments.