Conservation treatment represents an important moment in the life of an object, and this is particularly true for the Berthouville Treasure, an extraordinary group of Gallo-Roman silver that arrived at the Getty Villa two years ago. In collaboration with the Cabinet des médailles of the Bibilothèque nationale de France, this collection has come to the Getty for research, conservation, and eventually, exhibition. It is vital to document each stage of the conservation treatment so that future researchers and conservators can reconstruct exactly what was done, when, where, and by whom. This information is frequently missing from restoration interventions that objects underwent in the past, leaving it up to today’s conservators to try to reconstruct what has happened to an object, and whether changes occurred in ancient times or more recently. These discoveries inform our knowledge of art history and the materials and techniques used to create and care for works of art throughout time.
After their careful unpacking, each of the 93 objects was photographed in order to record its condition prior to the conservation treatment. We assess each object’s condition through these and other methods before beginning a treatment program. We are x-radiographing many of the objects to better understand their current state of preservation and how they were originally manufactured, and a collaborative metallurgical study of the silver vessels has begun with our Getty Conservation Institute scientific team. Studying the objects scientifically in this way will hopefully shed light on how the hoard fits into the larger context of silver production and distribution in the wider Roman Empire
The physical evidence provides many clues to the original manufacturing methods of the objects as well as evidence of past restoration practices. In addition, we are able to compare our findings to several archival literary sources from the 19th and 20th centuries. We have been able to work from an original 1916 copy of the Tresor d’argenterie de Berthouville by Ernest Babelon in the Research Library; the text and images contained within this reference book have been instrumental in reconstructing the history of each object.
After months of assessing each silver object’s condition, we started a light surface cleaning of two of the Berthouville objects, a plate depicting portrait busts of the god Mercury and his mother Maia (pictured at the top of the post before conservation treatment), and a wine vessel depicting Omphale with Eros figures laying on Herakles’ lion skin and club.
The silver surfaces were very dark and uneven in appearance when we began lightly cleaning them with dampened cotton swabs, which removed some of the accumulation of dust and grime. Even this initial cleaning revealed the gold gilded surfaces, details of inscriptions, and the figural work as well as how heavily scratched the bowls are from numerous cleaning campaigns both in antiquity and since their discovery in 1830.
After the initial cleaning with water to remove the grime, we used a combination of mild cleaning agents and solvents, such as acetone and ethanol, to remove additional grime, waxes, and tarnish. Chemically speaking, tarnish is silver sulfide. Whenever silver comes in contact with a sulfide (most commonly hydrogen sulfide in the air), it begins to darken. On the Berthouville silver, we carefully removed layers of tarnish until we achieved an overall unified appearance.
After the objects are cleaned, we store them with tarnish-inhibiting materials. Finally, we apply a layer of lacquer, which will protect the silver for years to come.
We will be working with the staff of the Bibliothèque nationale de France to establish materials for safe storage and display of the objects upon their eventual return to France. We are also developing protocols for optimum environmental conditions in order to protect the objects as they travel to additional exhibition venues and eventually back to their permanent home at the Cabinet des médailles.