Roman silver plate from Constantinople

During the initial examination of a 6th century Roman silver object,
a series of blisters were noticed on the surface that were raised
and measure up to 1 cm in diameter. The plate is made in several
thin sections and so it is clear that the top layer has been raised
up, "blistered". Further examination revealed that a core plate,
possibly silver as well, may have been cast first and two thin
layers of silver were later pressed or clad to both the front and
back surfaces, encapsulating the interior plate that was
manufactured with a figural image in relief.

The outer surfaces also have a spotted or mottled appearance, which
varies from gray to a slight rose/copper color. This is not
intentional decoration. We believe this may be "fire staining" that
may have occurred during a previous heating of the object to reshape
a bent and damaged area close to the rim. There is minimal
documentation remaining about past treatments. We are in the first
phase of documentation and treatment and are curious if anyone has
seen these kinds of issues on silver objects of any period and what
they have concluded about the manufacturing technologies, surface
changes and possible corrosion products.

Eduardo P. Sanchez
Associate Conservation of Antiquities
The J. Paul Getty Museum
1200 Getty Center Drive, Suite 1000V
Los Angeles, CA 90049-1745
310-440-7051
Fax: 310-440-5128


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                  Conservation DistList Instance 25:5
                   Distributed: Tuesday, July 5, 2011
                        Message Id: cdl-25-5-018
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