An XRF study on the pigments in wood carving of Jesuit missions of Argentina

Full text: The Jesuit organization in South America included Missions where doctrinal and cultural activities were done in order to civilize the native population. A series of Jesuitical ranches were built in the territories where the missions were located to complete the economical development of the Jesuit organization. There was no pomposity in the architectonic project of these farms because they used only local materials (rolling stones, algarroba wood, clay bricks and roof tile, lime, gypsum, melted metals, etc.). This work describes the use of X ray Fluorescence Spectrometry to study colonial Jesuitical art from the XVII century. A series of wooden painted carvings was analysed at CEPROCOR using a portable energy dispersive X ray fluorescence spectrometer. These pieces belong to the Jesuit missions placed in the centre or Argentina, recently categorized as cultural heritage of humanity. Pink and blue pigments of the smalt were studied because these colours are unexpected in colonial Jesuit art. The binder of enamel taking from the pieces where it was allowed to scrape was studied by IR spectroscopy. The thin gold layer was also studied, usually used in Jesuitical art to cover the wooden religious objects. This work is the beginning of a series of studies of Jesuit art pieces included in a restoration programme. The pieces analysed were chosen because the suspicions of restorers of an alteration in the colours of some parts of 'La Candelaria' altar. The Jesuits did not use the present colours observed in the carving. This is confirmed by the presence of Zn in blue, pink and white smalt, because the presence of ZnO pigment in the composition of smalt is later attributed to expulsion. This fact confirms the alteration of carving after the 3rd decade of century XIX. XRF studies do not reveal Au pigments in the layers conforming to the substrates of the smalt. (author)