Intrigued by arsenical findings, NGV conservators examined our own Morris wallpapers using x-ray fluorescence (XRF), a non-destructive form of analysis that aids the identification of metals, minerals and pigments. XRF uses a beam of radiation to force changes in a sample at an atomic level. These changes result in the release of secondary x-rays, the energies of which are characteristic of individual elements. The results are expressed as spectra. While arsenic was not located in the NGV sample, what was detected was the presence of lead, a leading domestic interior poison of the twentieth century.