Research Summary

Red lake pigments based on dyes extracted from natural organic materials were widely used by artists since earliest antiquity for painting on different supports. Their identification in artworks can expand the comprehension of the objects, the artists’ working methods and the technological skills and other aspects of the past. Since they are light-sensitive materials and their fading causes undesirable changes in the visual appearance of the artworks, the study of their state of degradation can also provide information on how the objects’ appearance has changed over time. However, their identification is a challenging task that requires the existence of an adequate reference database, together with the development of an effective in situ analytical methodology. This project will be dedicated to the study of red lake pigments, their chromophores’ properties and their story of use and manufacture, and will be focused on the creation of a comprehensive luminescence and reflectance hyperspectral imaging in the UV-Vis-NIR reference database of well-characterised chromophores of red dyes and historically accurate reconstructions of red lakes and paints. The data obtained with the references will be compared with that from coloured artworks in Florentine museums, which will help to confirm the usefulness of the database and of the use of hyperspectral imaging as an in situ analytical approach for the study of these materials.

PhD Project Title: Red Lake Pigments: from the study of their chromophores and historically accurate references to a comprehensive hyperspectral imaging database.

Supervisors: Marcello Picollo (IFAC-CNR Italy), António Jorge Parola (DQ FCT-UNL), Vanessa Otero (DCR FCT-UNL)