Analysis of Fe valence states in iron-gall inks from XVIth century manuscripts by 57Fe Mössbauer spectroscopy Original Research Article

The charge state of Fe in iron-gall inks was studied by 57Fe Mössbauer 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 Mössbauer spectroscopy were used in this work: (1) the detection of γ-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.