The "Mask of Agamemnon" is one of the most famous gold artifacts from the Greek Bronze Age. Found at Mycenae in 1876 by the distinguished archaeologist Heinrich Schliemann, it was one of several gold funeral masks found laid over the faces of the dead buried in the shaft graves of a royal cemetery. The most detailed and stylistically distinct mask came to be known as the Mask of Agamemnon, named after the famous king of ancient Mycenae whose triumphs and tribulations are celebrated in Homer’s epic poems and in the tragic plays of Euripides. The Metropolitan Museum of Art’s replica of this mask molded by Emile Gilliéron père (manufactured and sold by the Würtemberg Electroplate Company) is an example of an electroformed reproduction, also commonly known as an electrotype—or by the historic term, "galvanoplastic"—reproduction.
Electrotype technique was developed in the nineteenth century and was used to reproduce many different kinds of historic metalworks. It became an important means of disseminating information about historic cultures throughout the world in a time before readily accessible color images and widespread travel. An electrotype reproduction was thought of as a precise replica, even though the method of manufacture and the materials were not the same as those of the original artwork. In A Brief Account of E. Gilliéron’s Beautiful Copies of Mycenaean Antiquities in Galvano-plastic, the sales catalogue for the replicas, they were described as "exact imitations of the objects in Galvano-Plastic, in which the forms, no less than the brilliancy and colours of the metals, are faithfully reproduced." Gisela M. A. Richter—the eminent Metropolitan Museum curator who was instrumental in the acquisition of many of these reproductions—wrote that the copies were "of sufficient accuracy to give us a vivid idea of the originals."
In antiquity, the original mask was most likely raised from a single sheet of gold, just thick enough to hold its form without any waste of the precious metal. An example of an object in the Metropolitan Museum's collection that was made using this technique is the Late Helladic (ca. 1550–1500 B.C.) gold kantharos.
Gilliéron’s mask replica, however, was made by a completely different process. A comparison of radiograph images of these two objects clearly shows that a different method of manufacture was used to form the metal. Although it is already known—both from documentary records and visual inspection of the surface—that the replica mask under discussion is an electrotype, a lesser known object might be deceptively similar to an original artwork; a radiograph can provide valuable information as part of a thorough technical examination.
Several steps are involved in the manufacture of an electrotype. First, a mold of one surface of the original object must be made. In the case of the mask, the mold was clearly taken of the front surface in order to record the fine details of this featured side. The molding material must be able to separate easily from the original artwork while preserving its surface detail and overall form, and must also be capable of withstanding immersion in an electroplating solution. Several molding materials have typically been used, including plaster, sulfur, stearin, wax, gelatin, and gutta-percha, the latter substance being derived from the latex sap of the Palaquium tree found in the Malay Archipelago. In an 1887 catalogue discussing techniques used to make electroformed reproductions of objects from the Musée des Arts Décoratifs in Paris, the author notes that in his experience gutta-percha yielded the best results. Although it is possible that this was the choice of Gilliéron, his exact methods are not known. It is also possible that an additional step was used to preserve the initial mold—while moving further from the original artwork and, in some cases, losing detail in the process—this would have allowed for more copies to be made. A master mold would have been taken off the surface of the original artwork and a secondary mold taken from the master.
Once a mold was successfully made, it was coated with a fine, electrically conductive material such as graphite. This coating allowed the mold to act as an electrode onto which copper or another base metal could be plated in an electrolyte bath. In the case of the Mask of Agamemnon and most of the other gilded electrotypes in the Gilliéron group, copper was used. When the copper plating was deemed sufficiently thick, the process was stopped and the metal replica was removed from the mold. The front of the resulting copper electroform would be smooth and would preserve the surface features of the original, while the back would have an irregular topography reflecting the columnar growth of adjacent grains of metal in the electroforming bath.
To complete the process, a layer of gold was added to the surface. Analysis of the Metropolitan Museum’s replica using nondestructive X-ray fluorescence spectrometry (XRF) shows traces of mercury to be present (XRF spectra on file in the Department of Scientific Research). Although this could indicate fire gilding—a process known since antiquity and widely used for more than fifteen hundred years—it is more likely in the case of a modern electroform that mercury was used as a so-called quicking agent in order to facilitate the adherence of electroplated gold to the copper substrate.
The electroform process was used to replicate many famous artworks through the end of the nineteenth and into the twentieth century, and the results were exhibited in museums all over the world. These copies allowed the public to view facsimiles of works of art when the originals were not available. Even now, in the case of three-dimensional artworks, electrotypes give a close physical representation of an original object’s form and size and allow one to experience comprehensive views of an artwork in the round. Today, the Gilliéron electrotypes also remind us of the collecting practices of the Metropolitan Museum during its formative years.
A Brief Account of E. Gilliéron’s Beautiful Copies of Mycenaean Antiquities in Galvano-plastic, Württemberg, Germany, ca. 1906, The Archives of the Onassis Library for Hellenic and Roman Art.
Catalogue des Reproductions Galvanoplastiques des Objets D’Art destines Au Musée des Arts Décoratifs, Premier Fascicule Salle D’Exposition et Burreau de Vente: Chez MM. Christofle et Cie, Union Centrale des Arts Décoratifs, 1887.
Dickinson, Oliver. “The Face of Agamemnon.” Hesperia Vol.74, No. 3 (Jul.–Sep., 2005), American School of Classical Studies at Athens, pp.299–308.
Larsen, Erling Benner. Electrotyping. Copenhagen, Denmark: School of Conservation, Royal Art Academy, 1984.
Lins, Andrew. “Gilding Techniques of the Renaissance and After,” in Gilded Metals, History, Technology and Conservation, edited by Terry Drayman-Weisser, pp. 241–265. London: Archetype Publications in association with The American Institute for Conservation of Historic and Artistic Works, 2000.
Lins, Andrew and Sally Malenka. “The Use of Mercury Salts in Gold Electroplating,” in Gilded Metals, History, Technology and Conservation, edited by Terry Drayman-Weisser, pp. 267–282. London: Archetype Publications in association with The American Institute for Conservation of Historic and Artistic Works, 2000.
McLeod, B., M. Campbell and O. Nouvel. “A Christofle Electrotype of the Medieval Maitre Alpais Ciborium,” in The Heritage of ‘Maitre Alpais’: An International and Interdisciplinary Examination of Medieval Limoges Enamel and Associated Objects, edited by Susan La Niece, Stefan Röhrs, Bet McLeod, pp. 33–39. London: British Museum Press, 2010.
Neilson, Mike. “Electroforming: The Replication of Ancient Objects by Electrodeposition,” in The Heritage of ‘Maitre Alpais’: An International and Interdisciplinary Examination of Medieval Limoges Enamel and Associated Objects, edited by Susan La Niece, Stefan Röhrs, Bet McLeod, pp. 40–41. London: British Museum Press, 2010.
Richter, Gisela M. A. “Cretan Reproductions.” The Metropolitan Museum of Art Bulletin, vol. 5, no. 5 (May 1910). New York: Metropolitan Museum of Art, pp. 113–117.
Selwyn, Lyndsie. Metals and Corrosion: A Handbook for the Conservation Professional. Ottawa: Canadian Conservation Institute, 2004.
Wahl, William H. Galvanoplastic Manipulations: A Practical Guide for the Gold and Silver Electroplater and the Galvanoplastic Operator, Philadelphia: Henry Cary Baird and Co, 1883.
I would like to thank the following colleagues at The Metropolitan Museum of Art: Chris Singh (Department of Scientific Research), Richard Stone and Linda Borsch (The Sherman Fairchild Center for Objects Conservation), and, especially, Seán Hemingway (Greek and Roman Art).