Skip to content

AST: Hidden by Time: Terahertz Imaging Reveals Inscription on a Corroded Lead Funerary Cross

Dr. David S. Citrin, September 24th, 2022

In the Middle Ages to early modern times in Northern Europe, some elite burials included a lead cross placed on the deceased’s chest to facilitate (one hopes) the passage to the next world.  These funerary crosses typically had an inscribed prayer and sometimes the name of the deceased.  Over the centuries, the lead corroded in the damp earth which continued once exposed in air despite the fact that lead is often thought of as a corrosion-resistant metal.  That corrosion layer can obscure a reading of what is written on the cross.  

In a collaboration between Georgia Tech, a conservation lab, and a museum in France, Dr. Citrin used a novel imaging approach using terahertz electromagnetic waves to peer below the corrosion without removing it.  Terahertz waves are similar to microwaves, but with somewhat shorter wavelength.  Using a combination of clever data analysis approaches (not my idea, but those of a talented PhD student!), we were able to read the hidden inscription.  There are many other types of lead artifacts in museums, including sarcophagi, cups and plates, decorative items, and sewer and water pipes where this technique might be used.  This approach is of interest to art historians, conservators, and archeologists.

Speaker and Title-

David S. Citrin, PhD, Professor of Electrical and Computer Engineering, Georgia Institute of Technology

David S. Citrin received the B.A. degree in physics from Williams College, Williamstown, MA and the M.S. and Ph.D. degrees in physics from the University of Illinois, Urbana. He was a postdoctoral researcher at the Max Planck Institute für Festkörperforschung, Stuttgart, Germany and then at the University of Michigan, following which he was an Assistant Professor of Physics at Washington State University, Pullman. In 2001, he joined the Georgia Institute of Technology where he is a Professor of Electrical and Computer Engineering. In addition, he is a coordinator of research on nondestructive evaluation with the international research laboratory Georgia Tech-CNRS IRL2958, Georgia Tech Lorraine, Metz, France.

He has long been interested in art history, and finds using his technical background to work on art and archeological objects his most rewarding activity.  Citrin was a recipient of an award under the Young Investigator Program of the Office of Naval Research, of a Presidential Early Career Award for Scientists and Engineers, and of a Friedrich Bessel Prize from the Alexander von Humboldt Stiftung.


September 24th, 2022

Manuel’s Tavern, 602 North Highland Avenue Northeast, Atlanta, GA 30307

6:30pm – Doors Open

7:00pm – Gather at Manuel’s

7:20pm – Talk start

8:00pm – Q & A

Was this article helpful?


Ask A Scientist

Just your first name is alright. So we can write you back in our response article (think "Dear Sally" style)
In case we have any follow-up questions so we can properly answer yours

Science for Georgia is a 501(c)(3). We work to build a bridge between scientists and the public and advocate for the responsible use of science in public policy.

Back To Top