Bronzeguss des Barisanus von Trani – Neuer Artikel
This flowchart displays the principal steps of any mould making that uses lost moulds, resulting in one casting generation. It highlights those factors that contribute towards overall shrinkage and distortion of a cast object compared to its model. It is true for most casting operations in prehistoric and historical contexts and independent of the materials being used. Image: 2024 B. Asmus.
Zu den herausragendsten Meisterwerken mittelalterlicher Gießer gehören die massiven, aber auch die zusammengesetzten Bronzetüren in Italien, Deutschland, Polen und Russland. Zusammen mit dem Team vom Gates to Paradise Projekt, haben wir eine neue Untersuchung zur Gusstechnologie der drei Türen von Barisanus durchgeführt. Die Türen von Trani, Monreale und Ravello wurden hierfür neu und mit Hilfe der Photogrammetrie vermessen .
Da sich an allen drei Türen die gleichen Motive finden, wurde die Reihenfolge der Herstellung der Türen in der Kunstgeschichte kontrovers diskutiert. Um so erstaunlicher war es dabei für mich, das bisher noch kein einziger Kollege die Schwindung des Metalls herangezogen, geschweige denn systematisch untersucht hat. Durch den Einsatz der Photogrammetrie können die Messungen nun relativ einfach am Computer erfolgen.
Abstract:
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.
