CONICET | Buscador de Institutos y Recursos Humanos

South American polychrome sculptures were manufactured in workshops during the so-called Colonial period (XVII-XVIII C.) by Spanish, indigenous and creoles people. These images show the diverse iconographic discourses that were necessary to develop the evangelization process. The purpose of the present study was to characterize the pigments and plaster of a wooden South American polychrome sculpture produced in the Jesuit Mission of Trinidad in Paraguay. The sculpture is currently housed at the Museum of Natural Sciences, La Plata, Buenos Aires province, Argentina. Its conservation condition is rather poor but, as it has never been restored, it is a good example to study from a chemical, biological and historical point of view. Based on the anatomy of transverse and longitudinal sections observed under the light microscope, the sculpture wood was corroborated to be Cedrela fissilis. This cedar also called ygarí, was the most used wood in the Missions. Observation of the wood by SEM showed secondary cell wall cavities that were typical of soft rot. The fungi isolated and causative of the wood degradation were identified as Chaetomium globosum and Nigrospora sphaerica. Four microsamples taken from representative areas of the sculpture were analyzed for pigments and plaster identification. Cross sections of the samples were examined by optical microscopy and SEM-EDX. Analysis by transmitted FT-IR spectroscopy revealed the presence of chalk, CaCO3, as the plaster. Green earth was identified in two of the samples by a band around 1014 cm-1 in the FTIR spectra and its characteristic elemental composition by SEM-EDX. Recently, we have identified this pigment in a stone sculpture [[1]] and a ciborium produced in the Jesuit Missions of Paraguay during the XVIII century. The identification of calcium carbonate as the plaster is very interesting because gypsum was the most frequent preparation layer detected in other sculptures produced in the same Mission [2]. This fact might be showing the influence of Austrian masters active in those missions. [1] B. A. Gómez, S. D. Parera, M. S. Maier, G. Siracusano. Characterization of painting materials in a stone South American polychromy. IMRC 2009. LASMAC & Archaeological & Art Issues in Materials Science, Cancún, México. [2] M.S. Maier, B. A. Gómez, S. D. Parera and G. Siracusano. Integrated analytical techniques for the characterization of painting materials in two South American polychrome sculptures. E-Preservation Science 7, 1-7 (2010).