Recent applications to the study of ancient inks with the Florence external-PIXE facility

In the first part of the paper, the specific advantages of external PIXE in the applications to the analysis of ancient inks are discussed together with some problems in the quantitative analysis of the X-ray spectra as far as low-Z elements are concerned, which however come out to be of minor relevance for a discrimination among different inks, which is the main purpose of these investigations. In the second part, a few examples of the results we have recently obtained are illustrated. By detecting the ink composition we have been able to support attributions of several manuscripts, produced in central Italy from the 12th to the 15th century, to the same or different writers and periods. Within this group of manuscripts, a substantial difference was detected between those of the 12th century and all the others, possibly showing a technological evolution in the ink-making procedures. Finally, we report on the latest results of our project for an ink-based chronological reconstruction of undated documents by Galileo. By these results, such a project has now proved to have good chances of casting some light on controversial dating problems of these documents.