In situ analysis of ancient glass: 17^th century painted glass from Christ Church Cathedral, Oxford and Roman glass vessels

Handheld x-ray fluorescence spectrometry (HH-XRF) was successfully used to distinguish panes of 17^th century, high lime, low alkali (HLLA) glass from later restoration pieces within an in situ window in Christ Church Cathedral, Oxford. In addition the non-destructive analysis was able to differentiate between the work of two 17^th century artists within the same window. The varying compositions of glass present in the window represent the turbulent history of the cathedral glass, and the changing attitudes towards painted glass windows. Following the success of this work, a second study was undertaken to attempt to calibrate the HH-XRF for the analysis of Roman glass from museum and private collections. The results of the second study were disappointing; while the HH-XRF results of the standards compared well with the chemistry, the results of Roman glasses did not. This paper compares the two studies and addresses some of the reasons why the analyses of 17^th century HLLA glass was so successful, yet the analyses of Roman glass was unsuccessful. There is much potential for the use of HH-XRF within the correct research framework, but more work needs to be completed before this non-destructive technique can reliably replace destructive analyses.