Behind the Light: Pink-lake Paints’ Characterization on a 16th Century Illuminated Antiphonary held by the Biblioteca Pública de Évora – a Spectroscopic Approach

Abstract

The complete characterization of illuminated paints (pigments, extendersin its full composition (pigments, extenders, binders and any other additives) is a challenging task. If for inorganic materials it is often performed using in-situ and non-invasive analysis, for lake-pigment-based paints it becomes difficult to identify them via a non-invasive approach. This work focuses on the characterization of pink-lake paints present in the illuminations of Manizola 116c codex, a large 16th century Antiphonary produced to be used as a Choir book at the female Cistercian Monastery of São Bento de Cástris, Évora (Portugal). For this, the pink-to-reddish paints of seven representative illuminated capital letters were analyzed by in-situ fiber optic reflectance spectroscopy (FORS), and the results compared with 48 FORS reference spectra of historical accurate reconstructions of pink-lake pigments produced from four late-medieval-to-renaissance treatises. PCA analysis was performed on the 48 reference spectra, and the historical spectra projected into the PCA model. With this approach it became possible to identify the use of cochineal lake-pigments for either the roses and the reddish-pink paints. To corroborate the results, two micro-samples representative of these reddish-to-pink-lake paints were analysed by LC/DAD/MS.