Why are two bronze casts made by Michelangelo are losing intricate detailing of original models?
Faculty from the Warwick Manufacturing Group (WMG) and the Warwick Medical School at the University of Warwick in the UK are working in collaboration with art historians from the University of Cambridge. Their goal: to determine the design and construction process of two curious Renaissance bronzes.
The team has been utilizing neutron imaging, x-ray fluorescence (XRF) analysis, 360-degree laser scanning, 3D printing and real-time x-ray videography to assess why the thick-walled casts are losing the intricate detailing and sophistication of the original models.
The two bronzes, held at the Fitzwilliam Museum in Cambridge, first came to the world’s attention in February of 2015, when a group of experts asserted they were actually cast models by Michelangelo.
The museum brought in sculptor and archaeometallurgy expert Andrew Lacey to help construct one full-size and two reduced-scale replicas of the bronzes. To do this, Lacey used the traditional method of spruing for one of the scale models while using a more unorthodox method for the second, which he believes was used for their creation.
Lacey will be assisted by the WMG researchers, who will be providing high-resolution 3D scans of the bronzes and by Warwick Medical School professor Peter Abrahams, who will comment on their anatomy.
“There are anatomical features on the bronzes that could only have been known by someone who had dissected the human body or who had attended dissections,” said Abrahams. “Dissections were very rare before 1543 and the publication of Vesalius’ Fabrica, which was the first accurate and seminal anatomical text in the world. In the art world, only Leonardo [da Vinci] and Michelangelo had the anatomical knowledge, gained through the regular dissection of corpses that would have been necessary to produce such anatomically accurate nude figures.
“There is no primary proof of other artists who dissected corpses on a regular basis in the first half of the 16th century,” Abrahams adds. “Some features of the anatomy on the two figures are not visible on observation alone and could only have been known through the practice of cutting open cadavers. I have also identified features of detailed anatomy of the two figures that are peculiar to the documented sculptures of Michelangelo and which could be characterized as signature details.”
Abrahams continued, “I looked at the sartorius groove, the triangle of auscultation and the wrongly contracted two heads of gastrocnemius, as well as the details found in other known works of Michelangelo: i.e. hallux with abducted elongated second toe, coiffured and ‘blow-dried’ Tanner grade 5 male pubic hair position and distribution, rectus abdominis with anomalous extra tendinous intersection for an ‘8-pack,’ as seen also on some of his Pieta drawings and statues, a hooded umbilicus, as well as a stunning accuracy for over thirty muscles and bony points with a slight ‘hyper-anatomized’ style as is seen in others of his expressive male body drawings and sculptures.”
WMG professor Mark Williams then created an exact 3D digital model of the original bronze in Cambridge. The scanner used was able to resolve features below 100 microns to guarantee accuracy of the digital model. The scan was then sent to Propshop at Pinewood film studios to create the full- and reduced-scale 3D models.
“It was fantastic to apply our technology to such an exciting project and help shed light on the origin of such beautiful statues,” said Williams. “Usually we are working on something engineering-related, so to be able to take our expertise and transfer that to something totally different and so historically significant was a really interesting opportunity.”
Lacey can now use the molds from the 3D models to create the replicas utilizing an historically-accurate alloy, furnace and construction methods that would have been used during Michelangelo’s time.
The team has also brought in William Griffiths from the University of Birmingham’s Metallurgy and Materials Department to take x-ray videos of the bronze pouring to assess the liquid metal flows around the mold in order to better understand the complicated casting process.
The goal of this research is to elucidate early 16th century bronze making and the artistic process of renaissance masters.
The keeper of applied arts at the Fitzwilliam Museum said, “It has been wonderful to spearhead further interdisciplinary research into the Rothschild bronzes to better understand how they were made and why they look the way they do.
“Thanks to this novel collaboration between art historians, conservation scientists, anatomists, engineers, prop-makers and artists and through harnessing state-of-the-art equipment and imaging technologies, we can now reveal that these enigmatic bronzes were manufactured using some rather idiosyncratic working practices, which lends further weight to the early date already suggested by visual and preliminary technical analysis.”
The collaboration between art historians from the University of Cambridge, conservation specialists at the Rijksmuseum in Amsterdam, an anatomist and 3D scanning experts at the University of Warwick, metallurgists from the University of Birmingham, and Andrew Lacy was displayed at the Michelangelo Discovery event on July 6 in Cambridge.