Blues from Tikuna/Magüta Masks and a Still Unknown Blue Colorant in Technical Art History and Conservation Science

Blue is one of the most challenging colors for humans to produce and one of the most important colors in art history. Literature from the Tikuna/Magüta culture, from the Amazon Forest, suggests the use of chemical reactions between the juice of the naīcü fruit and iron to produce a blue colorant still unknown among technical art historians and conservation scientists. Additionally, the coloring materials from the Tikuna/Magüta people were never chemically investigated. Therefore, this manuscript presents the investigation of blue colorants from twenty-two Tikuna/Magüta masks and one stamp used to decorate similar items. Collections from four museums, from the USA and Brazil, were examined, and Raman spectra indicated the presence of Prussian blue, phthalocyanine blue, indigo, ultramarine, crystal violet, amorphous carbon, anatase, and barium sulfate (or lithopone). Although the unknown blue colorant was not detected in this campaign, the authors hypothesize the chemical composition and reactions involved in its production by considering the chemistry of naīcü and anthocyanins. The continuation of this work with community-based participatory research (CBPR) approaches is also discussed, justifying why reproduction was not considered in this work and supporting a more socially responsible and inclusive practice in technical art history and conservation science.