http://www.kunsthaus.ch/en/the-collection/conservation/examples-from-the-world-of-art-conservation/auguste-rodin/stage-2/initial-tests/initial-tests-copper-test-plates/?redirect_url=title%3Dthe%20%20%2F%2F%3Fcontent%3D

Kunsthaus Zürich

Initial tests

Copper test plates for protective covering agents (Photo:  G. Pegurri)
Copper test plates for protective covering agents
(Photo: G. Pegurri)