The Polychromatic Inscriptions on the Relief Sculpture Deposition from the Cross by Benedetto Antelami in Parma Cathedral, Italy

This paper reports on the studies carried out on engraved inscriptions of the Deposition from the Cross by Benedetto Antelami (1150–1230), a relief sculpture conserved in the Cathedral of Parma (Italy). The inscriptions between the characters show residues of colored material in alternating red- and dark-colored stripes. The purpose of this specific investigation was to identify the materials (pigments and organic binders) used for the polychromy that are still present on the relief sculpture. Seven microsamples were taken to carry out laboratory analyses. In red-colored letters, mercury, and sulfur, constituents of the cinnabar (or vermilion) pigment were easily identified by SEM-EDS. This result is confirmed by Raman spectroscopy and XRD measurements. In the dark letters, carbon, iron, and lead are observed. The presence of materials containing metals is compatible with a mastic encrustation technique. FT-IR, Raman, and XRD techniques clearly detect beeswax, which was probably used as a polishing material. Amino acids and lipids that are typical of eggs have been identified by means of GC-MS investigations, suggesting their use as organic components of the mastic encrustation.