[1] Univ Nova Lisboa, NOVA Sch Sci & Technol, LAQV REQUIMTE, P-2829516 Caparica, Portugal
[2] Univ NOVA Lisboa, NOVA Sch Sci & Technol, Dept Conservat & Restorat, P-2829516 Caparica, Portugal
[3] Tate Britain, Conservat Dept, Millbank, London SW1P 4RG, England
[4] Univ Glasgow, Kelvin Ctr Conservat & Cultural Heritage Res, Sch Culture & Creat Arts, Glasgow G12 8QH, Scotland
[5] Natl Museum Denmark, Environm Archaeol & Mat Sci, DK-2800 Kongens Lyngby, Denmark
[6] Univ NOVA Lisboa, NOVA Sch Sci & Technol, Dept Chem, P-2829516 Caparica, Portugal
[7] Univ Nova Lisboa, CIUHCT Interuniv Ctr Hist Sci & Technol, NOVA Sch Sci & Technol, P-2829516 Caparica, Portugal
[8] Univ NOVA Lisboa, NOVA Sch Sci & Technol, Dept Conservat & Restorat, P-2829516 Caparica, Portugal