Raman and Infrared spectroscopy in the
field of Cultural Heritage.
Raman and Infrared Spectroscopy are widely employed in the field of Cultural Heritage since allow to identify both the
different components present in any artwork through their characteristic vibrational frequencies. Micro-Raman
spectroscopy, in particular, has assumed in recent years an important role in archaeometry, since very small samples
can be investigated with high spatial resolution (few microns), which is essential in the case of chemically
heterogeneous samples, as the artwork ones.
In the framework of a collaboration program with archeologists of ISCIMA-CNR and Universita’ di Napoli, we studied
Etruscan polychromes on terracotta from the Cerveteri area: the Ceri warrior, a large terracotta panel employed to adorn
internal spaces (now on display at the Cerveteri Etruscan Museum), two architectural terracotta panels (now on display
at the Villa Giulia Etruscan Museum in Rome), and fragments of potsherds decorated with the characteristic white-onred technique. The use of Raman and infrared analysis, combined with the XRD analysis made by our collaborators,
allowed an almost complete determination of the color palette employed by Etruscans in decorating terracotta objects.
Of particular interest is the identification of kaolin as white pigment. This result has been obtained by infrared
spectroscopy, by comparing samples of white color with samples collected from a kaolin quarry in the Cerveteri area.
Main publications in the field are:
- F.Bordignon, P.Postorino, P.Dore, G.F.Guidi, G.Trojsi, V.Bellelli, “In search for Etruscan colours: a
spectroscopic study of a painted terracotta slab from Ceri”, Archaeometry 49, 87 (2007).
- F.Bordignon, P.Postorino, P.Dore, G.Trojsi, “Raman identification of green and blue pigments in
Etruscan polychromes on architectural terracotta panels”, J. Raman Spectrosc. 38, 255 (2007).
- F.Bordignon, P.Postorino, A.Nucara, P.Dore, G.Trojsi, V.Bellelli, “The white colour in Etruscan
polychromes on terracotta: spectroscopic identification of kaolin”, J. Cultural Heritage 9, 23 (2008)
In the framework of a collaboration program with the Istituto Centrale per il Restauro (ICR, Rome), we performed
micro-Raman measurements on polished cross-sections of samples from the painted lunette of the portal of the Basilica
of San Zeno Maggiore in Verona. The high spatial resolution and chemical selectivity of the micro-Raman technique
allowed a detailed identification of the species present in the different layers. In particular, a significant occurrence of
large amounts of metal oxalates was observed. Obtained results, which contribute to an understanding of the origin of
metal oxalates in the polychrome and allow reliable hypotheses to be advanced concerning the ageing processes of the
painting materials, have been published in:
- F.Bordignon, P.Postorino, P.Dore, M.Laurenzi-Tabasso, “The formation of metal oxalates in the painted layers
of a medieval polychrome on stone, as revealed by micro-Ramanspectroscopy”,
Studies in Conservation 53, 158-169 (2008).
The Ceri warrior
510-500 a.C.
53,3 x 84,3 cm
Identification of red and blue pigments in the Ceri warrior