The RTI Technique is a non-invasive multispectral diagnostic tool that allows the study of the surface morphology of any kind of artefact, obtaining fundamental information that cannot be perceived by visible light. The technique involves the application of photographic methods to characterise the surface. This information is translated into a digital image composition that describes, for each pixel, the chromaticity and surface morphology of the subject. The real innovative strength of the RTI diagnostic survey is to obtain a scientific and unequivocal and easy-to-read document describing the colour and the real three-dimensional morphology of the surfaces.
Mnemosyne Servizi applied RTI to a large number of artefacts including, for the first time in history, a page of the Gutenberg Bible (B42). The aim of the investigation was to analyse such an important object in an unusual and extraordinary way and to uncover any hidden data that might provide an indication of the use of the movable typeface. As is well known, the B42 is the first printed text produced using movable type.