Analysis of Fe valence states in iron-gall inks from XVIth century manuscripts by 57Fe Mossbauer spectroscopy

The charge state of Fe in iron-gall inks was studied by 57 Fe Mossbauer spectroscopy. Three ancient manuscripts from the 16th century and a set of model samples were characterized. The chemical fingerprint was found to be well defined for the ancient manuscripts whereas the model samples show a larger spread of chemical states. Two different modes of Mossbauer spectroscopy were used in this work: (1) the detection of gamma-quanta in the usual transmission mode and (2) the detection of conversion electrons in backscattering geometry in a special parallel plate avalanche counter. The use of these two measuring modes allowed to reveal differences between the chemical features of the core and the surface of the iron-gall ink structures. (C) 2004 Elsevier B.V. All rights reserved.