Characterization of corrosion products on chalcographic copper plates after 200 years' exposure to indoor atmospheres

This work studies the characterization of corrosion products formed on six eighteenth century chalcographic copper plates preserved in the National Chalcography Collection in the San Fernando Royal Academy of Fine Arts in Madrid. The experimental methods used were X‐ray diffraction analysis (XRDA), Infrared spectroscopy (IRS), Auger electron spectroscopy (AES) and X‐ray photoelectron spectroscopy (XPS). The main compounds found were malachite CuCO 3 · Cu(OH) 2 , atacamite CuCl 2 · 3Cu(OH) 2 , nantokite CuCl, tenorite CuO, and cuprite Cu 2 O. Cuprite is the main compound found on the smooth areas of chalcographic plates, forming tarnish films. The thickness of the tarnish films is approximately 10–15 Å.