Spectral characterization of ancient wooden artefacts with the use of traditional IR techniques and ATR device: a methodological approach

This work presents a methodological approach to the study of ancient wooden artefacts by using FT-IR techniques. Sampling is one of the most important steps in investigating works of art. However, samples should be taken only when this operation does not appreciably modify any of the parts, or change the integrity, of the wooden artefacts in question. Although it was invasive, a low-destructive method of sampling was used on wood meal in order to obtain reproducible results. Moreover, two modes of operation were compared, namely the transmission mode (carried out on pellets of wood meal mixed with KBr) and the Attenuated Total Reflectance (ATR) mode (carried out directly on wood meal). For the former, the effect of the concentration of wood in KBr also was considered. The results evidenced a similar quality of spectra, although a different sensitivity between the two techniques in some spectral ranges was observed. The final focus of this research will be on validating the use of IR spectra to date wooden materials.