The 3D Ultraviolet Fluorescence Imaging in Cultural Heritage: A Review of Applications to Multi‐Material Artworks

Ultraviolet fluorescence imaging represents a simple but powerful technique in cultural heritage studies. It is a relevant nondestructive and non-invasive imaging technique able to supply several useful information to define the state of conservation of an artefact. This also helps to establish the value of an artwork, by observing eventual inpainting, repaired areas, grouting, etc. Generally ultraviolet fluorescence imaging output is made of 2D photographs both in the case of paintings and sculptures. For this reason, a few years ago our idea was to develop a photogrammetric method to create 3D digital twins under ultraviolet fluorescence to address the requirements from restorers who need daily documentation tools for their work that would be simple to use and able to display in a single file the entire 3D object. The method was first applied on a reliquary bust made of papier-mâché and, due to the success of the result and to the positive feedback from the restorers, subsequently on various other 3D artworks. The photogrammetric methodology was based on a digital camera, two filters positioned in front of the lens, two ultraviolet led lamps filtered at 365 nm and processing software for obtaining the 3D models under ultraviolet fluorescence imaging. Ultraviolet 3D models were made available on Sketchfab, a platform for sharing 3D and AR on the web. The 3D models may be observed, rotated, enlarged by accessing Sketchfab through a computer, a tablet or a mobile allowing the restorers to use this tool even during their work in the field.