Chemical Aspects of Degradation of Historical Documents with Iron Gall Inks

Iron gall inks (also known as iron gall nut ink or oak gall ink), are considered to be one of the most important inks in the history of Western civilization. Transition metals and the acids present in the inks induce degradation of paper, thus seriously damaging many historical artifacts. Properties of historical documents and drawings written with iron gall inks are presented. Composition, chemical properties, degradation mechanisms and stabilization of the inks are discussed.