CONICET | Buscador de Institutos y Recursos Humanos

A first approach to the walls of the church of Copacabana de Andamarca, in the Bolivian department of Oruro, led to the discovery of a mural underneath a layer of white painting and plaster. The paintings, dated from the early eighteenth century, depict the eschatological subjects of Death, Judgment, Glory and Hell. The pictures of the Last Four Things were vital for the Catholic believe, since they had as purpose to recall the believer the finitude of life and the eternal bliss that awaited those who pursued Gods path and the endless punishments reserved for sinners. Since the Council of Trent, this message was particularly promoted by the Jesuit order who spread this message by the mean of preach, texts and images. This is particularly clear in South American context, where the paintings of the Last Four Things that can be found in temples like Carabuco, Huaro and Caquiaviri among others were considered essential for the evangelization of natives. The walls of Copacabana de Andamarca portray Saint Michael with the balance, the opened mouth of Leviathan where reprobates fall and the road to Heaven, all recurrent topics of this iconography. Since the discovery of these paintings a team of specialist advanced in the study, restoration and conservation by means of cleaning and consolidation of the surface of the walls. As first step of the analysis, cross sections of the samples were examined by optical microscopy and SEM-EDX. Then, application of transmitted FT-IR spectroscopy and micro-Raman spectroscopy confirmed the presence of gypsum, Ca2SO4.2H2O as the plaster layer. Hematite, identified by micro-Raman spectroscopy by bands around 292 and 411 cm-1 was the pigment used to give the reddish color of the flames spilled out from the mouth of the Leviatan, and for the decoration on the flowers. Carbon black and indigo were clearly identified by bands in their Raman spectra at 1360 and 1590 cm-1, and 546, 599 and 1575 cm-1, respectively. Two green samples showed copper in its elemental composition by SEM-EDX. Further analysis by micro-Raman spectroscopy showed a band at 960 cm-1 characteristic of verdigris, a copper (II) acetate most frequently used as an artistic pigment.