Study of copper nitrate‐based patinas

Artificial patination is mostly based on empirical recipes for which the result is difficult to forecast. Little is known about the final corrosion compound formed on the patinated object. Therefore, different patinas based on copper nitrate—an ingredient recurrent in numerous references—were realized according to traditional recipes. Their characteristics of morphology and molecular composition were studied using various methods such as scanning electron microscopy (SEM)‐energy dispersive X‐ray analysis (EDX), X‐ray diffraction analysis (XRD) and Raman spectroscopy (RS). A better understanding of artificial patinas will not only allow developing appropriate methods of conservation and restoration, but also differentiating between natural and artificial patinas. An example of a patina present on an ancient artifact is discussed and compared with the studied artificial patinas. Copyright © 2006 John Wiley & Sons, Ltd.