X-ray tomography for manuscripts

Abstract

This review presents the studies and the results achieved in the framework of the “Virtual X-ray Reading – VXR” project devoted to X-ray tomography for manuscripts. 

The project started in 2014 at École Polytechnique Fédérale de Lausanne (EPFL, Switzerland) and was part of the ambitious “Venice Time Machine” project. VXR aimed to test the feasibility and develop an alternate digitization technique for ancient manuscripts based on X-ray tomography. Research and technology made considerable progress in increasing the speed and the safety of the traditional digitization process of ancient collections, but, despite this, imaging of ancient, fragile, or un-opened documents remains a formidable challenge. Thanks to the high penetration of X-rays, using X-ray tomography, the acquisition of a 3D – tomographic – volume is possible even without opening the document. The X-ray contrast necessary for the readability is linked to the chemical composition of the ancient inks, such as the high X-ray absorption of the iron gall inks mainly used for centuries in Europe. In this review, I present the studies conducted to develop this technology, from the investigations on the ink chemistry to the imaging feasibility tests performed using extensive centralized facilities such as synchrotrons and the imaging of a 200-pages manuscript book the tomography of a 14^th Venetian sealed last wills.