XRD and FTIR characterisation of historical green pigments and their lead-based glazes

Abstract

In this study, the applicability of X-ray powder diffraction (XRD) analysis and Fourier transform infrared (FTIR) spectroscopy to investigate historical green pigments and their glazes was evaluated. In order to verify the ability to detect pigments in their glazes of the above techniques, the XRD and FTIR analyses were performed on the model samples. The investigation was pursued on nine pigments (Kremer Pigmente): malachite, verdigris, cobalt green, cobalt bottle green, chrome oxide green, Egyptian green, Victorian green, Florentine green and green jasper. The same pigments together with lead oxide and silica were used to prepare lead-based glazes. The results revealed that the XRD analysis is a useful tool for qualitative determination of the composition of glazes, although in some cases other analytical techniques should be involved. However, FTIR spectroscopy in the high wavenumber range (4 000–600 cm–1) does not give reliable results in the determination of green pigments in glazes.