Use of diffuse reflectance Fourier transform infrared spectroscopy in art and archaeological conservation

Abstract

The potential of Fourier transform infrared spectroscopy (FTIR) as an analytical technique for archaeological organic residues is being investigated. The application of diffuse reflectance spectroscopy to FTIR has made the analysis of small amounts of solid sample quick and reliable with minimal preparation. The FTIR spectrometer has computer facilities that are being used to compile a reference library of mineralogical specimens of bitumens, asphalts, resins, gum resins, shellacs, and waxes. The computer is also used to compare spectra of unknown residues with the reference library. Silicon carbide paper is being utilized to prepare the sample and as the sampling medium. The coating of a Gaudier Brzska sculpture and the residue from the linen attached to an Egyptian cartonnage have been identified using diffuse reflectance spectroscopy and computerized search of the reference library. Future work includes the use of an infrared microscope.