Micro-Raman and particle-induced X-ray emission spectroscopy for the study of pigments and degradation products present in 17th century coloured maps

Three different maps of the 17th century, two of them of Portugal and the third of the Iberian Peninsula, all of them hand colored and of Dutch manufacture (copper engraving).

Two techniques, PIXE giving elemental information and Raman providing information at a molecular level.

It was possible to identify the inorganic pigments used in the three maps, as well as some products of degradation whose causes are not completely understood yet.

This article contributes to a better knowledge of the techniques and palettes used for the coloring of maps of this period as well as the degradation of the pigments.

Particular attention is given to the presence of a copper oxalate found in two different maps, its presence being associated with green-colored areas and indicating degradation of a copper-based green pigment.