Today’s blogger is Dr. Gregory Dale Smith, the Otto N. Frenzel III Senior Conservation Scientist at the IMA. Dr. Smith is reporting through a series of blog posts on the IMA’s involvement in an exhibition at the Kelsey Museum of Archaeology in Ann Arbor, Discovery! Excavating the Ancient World.
A year ago this week, I boarded a plane for Egypt carrying a small “mobile lab” to take part in a collaborative fieldwork project studying ancient wooden funerary objects. As I reported earlier, the goal was to determine better conservation methods for stabilizing these beautiful, but fragile painted artifacts, which include decorated sarcophagi and statues. As the group’s chemist, my job was to use portable analytical instruments to identify the pigments, adhesives, and binding media used in the surface decoration of these deteriorated objects. On this one year anniversary, I wanted to wrap up my blog series by presenting some of our results from this exploratory season in the field at Abydos.
Our analyses showed that the ancient Egyptian artists used natural materials to decorate the tombs of their dead (Fig. 1). The binding agents for their paints included glue made from boiled animal skins and resinous gums exuded from plants. The colorants were also largely natural minerals including white chalk, yellow and red earths, soot black, and the poisonous arsenic containing yellow mineral orpiment. The primary blue pigment, however, was synthetic; Egyptian blue, a copper-containing glass frit was first made in Egypt as early as the 4th Dynasty around 3000 BC. Armed with this information about the paint composition, conservators are able to choose the most appropriate consolidants to stabilize these often disintegrating artifacts.
We also encountered other decorative elements including the inlaid eyes (Fig. 2) from wooden Ka sculptures found in the chapels associated with royal tombs. These are composite structures that include metal eyelids identified as pure copper sheet soldered together with lead and limestone whites of the eyes carved around a central black pupil of imported volcanic obsidian. The black gemstone was held in place with a plug of beeswax. Future work might include using chemical analysis to trace the foreign source of these luxury trade items.
One further outcome of this highly successful exploratory field season is the exhibit Discovery! Excavating the Ancient World at the Kelsey Museum of Archaeology at the University of Michigan. The work of the conservation team was included in the exhibition’s didactics to show the diversity of disciplines that contribute to our understanding and preservation of archaeological materials (Fig. 3). All of those who were part of this field season are extremely grateful to our home institutions for the latitude to come together to participate in this exciting project, and to the American Research Center in Egypt (ARCE) who along with the University of Michigan funded the expedition. Aside from being a fascinating study with components of ancient technology, complex biodeterioration, and delicate preservation interventions, our work in Egypt was a lot of fun (Fig.4)!