SELECTIVE DATING OF PAINT COMPONENTS: RADIOCARBON DATING OF LEAD WHITE PIGMENT

Lead white is a man-made white pigment commonly used in works of art. In this study, the possibility of radiocarbon dating lead white pigments alone and in oil paints was explored using well-dated lead white pigments and paints. Resulting C-14 ages on lead white pigments produced following the traditional stack process, where carbonate groups results from the incorporation of CO2 originating from fermentation, matched the production years, while radiocarbon dating of lead white made using other industrial processes indicate that C-14 depleted CO2 was used in their production. The method was applied to two case studies, where lead carbonate samples were dated in two oil paintings, one Baroque and one from the 20th century. We hereby show that the lead white pigment can be dated by C-14 and used as proxy for the time of creation of an artwork. Additionally, a two-step method was developed to allow C-14 analysis of both the lead white pigment and oil binder from the same sample. A single lead white paint sample can yield two distinct radiocarbon ages, one from the carbonate and one from the natural organic binder. This study thus proposes new strategies for C-14 dating of artworks.