Ellenor Alcorn, associate curator in the Department of European Sculpture and Decorative Arts at The Metropolitan Museum of Art, explains the nineteenth-century process of electrotyping and how it was
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used to create presentation copies of Tiffany and Company's famous silver Bryant Vase.
Related exhibition:
Victorian Electrotypes: Old Treasures, New Technology
On view November 22, 2011, through April 22, 2012
Transcript:
Ellenor Alcorn: The Bryant Vase was completed in 1876 by a team of skilled artists working for Tiffany and Company. They worked for more than a year meticulously chasing the sterling silver. Tiffany made a second vase for presentation using the electrotyping process.
To make an electrotype, molds are taken of each section of the vase. A flexible molding material is applied to the surface —in this case, gutta percha, the sap of an East Indian tree.
The mold hardens, leaving a precise impression. A coating of graphite makes the interior of the mold electrically conductive. Wires are attached to the inner surface. The mold is suspended in a copper-sulfite bath with a piece of copper and an electrical charge is applied.
The negatively charged graphite attracts the positively charged copper ions, eventually building up to form a thick copper wall. When the copper is thick enough, the mold is removed from the bath. The copper form is separated from the mold.
Additional copies can be made using this first example as a master pattern. The edges are trimmed and filed. The sections are soldered together. Then the copper is plated with silver, by immersing it in a bath of silver cyanide with a piece of silver. When the electrical charge is applied, a layer of silver is deposited on the surface.
In order to perfectly match the original, the copy is oxidized. On the surface, the two vases seem to be identical in every minute detail, though the copper vase was made in much less time.
Electrotyping had far-reaching uses, in the duplication of works of art, in manufacturing, and in the printing industry. This technology was one of many radical innovations made possible by the growth of electrical science.