Fig. 1

a Visible light detail of the Girl’s face. René Gerritsen Art & Research Photography; b false-colour first derivative of the reflectance cube image (RGB: 600, 540, and 450 nm), inset shows first-derivative endmember spectra used to make the maps in c; c maps of the first derivative spectral endmembers, ‘red’ = mainly vermilion, ‘green’ = ochre with vermilion, and ‘blue’ = mainly ochre; d MA-XRF map of lead (Pb L) with intensity adjusted to emphasise presence of lead in the face rather than the background; e MA-XRF map of mercury (Hg L); f MA-XRF map of iron (Fe K)