Poisonous books: analyses of four sixteenth and seventeenth century book bindings covered with arsenic rich green paint

Efforts to read medieval manuscript waste recycled as bookbinding material in the sixteenth and seventeenth centuries have resulted in the chemical analysis of four books housed at the University Library of Southern Denmark and the Smithsonian Libraries in Washington DC. Four green coloured book bindings have been investigated by optical microscopy, micro X-ray fluorescence, X-ray diffraction, Raman spectroscopy, mass spectroscopy, and laser ablation inductively coupled plasma mass spectrometry. The results show that the green pigments used to obscure the manuscript waste in all four cases contain orpiment (As ₂S ₃) and indigo (C ₁₆H ₁₁N ₂O ₂). Although the books were printed in diverse places in Europe—Basel, Bologna, and Lübeck—the styles of their bindings indicate that they were likely bound in the same region in the same period. It is further likely that they acquired their arsenic-rich paint as part of the bookbinding process. Issues concerning the toxicity, health issues for library staff, conservators and researchers handling the books are also addressed.[Figure not available: see fulltext.].