Analysis of Pigment Palettes as Evidence for Room Status in Nero's Golden House

The British Museum houses a group of twelve Roman wall paintings from the emperor Nero’s palace in Rome, the Domus Aurea or “Golden House”. They were discovered around 1850 by the owner of a vineyard whose land sat atop the ruins, then primarily known as the decorated caves that inspired the grotesques painted by Raphael and other Renaissance artists. Brief analysis in the 1980s verified the presence of high-quality gold leaf and the expensive red pigment, cinnabar. When one was selected for display in the UK touring exhibition Roman Empire: Power & People (2013-2015), it prompted conservation and further research of the entire group. The paintings display rich use of shade and texture through stucco modelling and impasto paint. Optical microscopy, x-ray fluorescence spectroscopy (XRF) and visible-induced luminescence imaging (VIL) enabled closer investigation of the materials used to decorate the original surface. These revealed additional remnants of gold leaf and extensive application of cinnabar and Egyptian blue. The findings enhance understanding of the historical context of the paintings: they confirm visual distinctions already made between styles of paintings from different rooms and demonstrate that the hierarchy between rooms dictated selection of materials.