Fig. 6

a FT-IR spectra obtained for the preparation layer of A Man from the Desert, Pedernal and the commercial pre-primed canvas roll; artist primed canvas grounds (Pink and Green and Storm Cloud, Lake George). b FT-IR spectra obtained for the ground layer of the commercial canvases. c Detail of the IR bands in the region of 1800–1700 cm⁻¹. d FT-IR spectra obtained for the soap protrusions from Pedernal and the commercial pre-primed canvas roll. All IR spectra were normalized to a single peak (2929 cm⁻¹) and plotted offset for clarity