Deconstructing Barisanus' medieval casting technology based on digital twins

The Italian 12th-century copper alloy doors of Barisanus have long been the subject of art historical studies and have recently been fully documented photogrammetrically and archaeometrically. In addition, digital twins of the three Barisanus doors in Ravello, Trani and Monreale have been produced and made available in open access for further research. These digital twins, together with the orthophotos produced, allow precise and repeatable measurements of the different metal parts of the doors, such as panels and frieze elements. This, and by taking into account the solid shrinkage of metals during the casting process, allowed for the reconstruction of the production sequence for each of the 20 single motif panels present on all three doors, and, finally, also for the establishment of the production sequence of the three doors as a whole-heavily discussed in art history research-with rather astonishing results. Moreover, bronze casting techniques used and the use of moulds and models are discussed, painting a more detailed picture that goes beyond the often purported dichotomy of lost wax vs. sand casting.