Investigation of Egyptian Blue on a Fragmentary Egyptian Head Using ER-FTIR Spectroscopy and VIL Imaging

Abstract

Non-invasive techniques are being increasingly used for the study of heritage objects. This article describes the results of pigment analysis on a fragmentary Egyptian sculpture using two non-invasive infrared methods: external reflectance Fourier-transform infrared (ER-FTIR) spectroscopy and visible-induced infrared luminescence (VIL) photography. ER-FTIR spectroscopy was used to identify certain of the pigments used on the sculpture, including Egyptian blue, in variously coloured areas. An optimized VIL photographic technique, using a high-resolution camera combined with focus-stacking, permitted detailed mapping of the location of Egyptian blue on the sculpture, including sub-millimeter grains of the pigment scattered across the object’s surface, which were not visible to the naked eye.

Keywords

• infrared luminescence
• VIL
• focus-stacking
• ER-FTIR
• FTIR reflectance