Special Studies: Application of Xeroradiography to the Study of Bronze Coins

Abstract

The present studies were carried out to determine whether xeroradiography could identify bronze coins with high lead content and record surface detail that might otherwise be lost during cleaning. From a collection of more than 2000 Greek, Judaean, Roman, Byzantine, and Islamic coins, selected studies were carried out that demonstrated that 1) image variation produced by penetration of x-rays through coins is the result of surface design and coin thickness as well as lead content, 2) details on corroded coins are detectable by radiography even when surface features were markedly worn, and 3) chemical and mechanical cleaning of coins commonly causes loss of diagnostic detail that can be recorded in xeroradiographs. From these findings it is concluded that xeroradiography is not helpful for recognizing bronze coins with high lead content, but is of use for identifying features in heavily corroded coins that may require special attention during conservation.