The Portland Vase, the best known piece of Roman cameo glass with art produced by etching, may have been wrongly classified for centuries.
A researcher at the Australian National University (ANU) believes archaeologists, historians and museum curators have for hundreds of years incorrectly classified Roman cameo glass from 30BC-50AD as blown glass – including the British Museum’s Portland Vase.
Instead, the research indicates that the Roman cameo glass was not blown glass, but was made by a cold-pressing process known as ‘patte verre.’
The Portland Vase (pictured), the best known piece of Roman cameo glass with glass art produced by etching, may have been wrongly classified for centuries. The vases, which has long been classified as blown glass, was actually made by grinding glass into a fine powder
WHAT IS PATTE VERRE?
Patte verre, or patte de verre, which is French for ‘glass paste,’ is a glass casting process.
The method involves grinding glass into a fine powder, with the addition of a binder to create a paste.
The pate is brushed or tamped into a mold, then dried and fused by firing.
After annealing, it is removed from the mold and finished.
Source: Corning Museum of Glass
Associate Professor Richard Whiteley from the ANU School of Art and Design will present his new evidence at a historical glassworks conference at the British Museum next week.
Professor Whiteley, who is known internationally for his glass artworks, said his research over the past decade indicated the Roman cameo glass was not blown glass.
‘There was a critical moment for me when I felt strongly that historians and archaeologists have been wrong for hundreds of years,’ Professor Whiteley said.
Whiteley’s research was based in part by examining a fragment of Roman cameo glass from the ANU Classics Department under a Computed Tomography scanner – an imaging technique in which a narrow beam of x-rays is aimed at the object, generating cross-sectional images of specific areas and allowing researchers to see inside the object without cutting it.
The images for the first time revealed the shape, direction and composition of air bubbles trapped between a blue and white layer of Roman glass.
‘I remember the moment I saw it, I said: Oh my god, this is extraordinary, because I also saw cold working marks in the surface which were inconsistent with the assumption that it was blown,’ Professor Whiteley said.
‘I carve and shape glass with my hands, and have done for decades.
A researcher at the Australian National University believes that archaeologists, historians and museum curators have for hundreds of years incorrectly classified Roman cameo glass from 30BC-50AD as blown class – including the British Museum’s Portland Vase (pictured)
‘The marks I saw were inconsistent with what I see in my work.
Whiteley said his team saw a bubble configuration within the glass that results from a pressing and turning motion.
‘I believe that cold granulated glass has been packed into a mould and then a blob of molten blue glass introduced and pressed against mould heating the white granules from behind.
‘You just would not get a bubble that size and flat-shaped from blowing.
The research was based in part by examining a fragment of Roman cameo glass under a Computed Tomography scanner – an imaging technique in which a narrow beam of x-rays is aimed at the object, allowing researchers to see inside the object without cutting it
‘The most striking thing about it, is not its size and its flatness, but we found a section where the blue glass has mixed with the granulated white specks of glass.’
Whiteley acknowledges a German artist, Rosemarie Lierke, came to a similar finding in the 1990s, but her writings have not been accepted due to a lack of evidence.
Whiteley hopes that his theory will gain acceptance and funding so that a team of international researchers can recreate the Portland Vase using the original patte de verre method.
‘It’s not about proving people wrong, it’s about correcting the historical record and reviving and restoring a technique lost for over 2,000 years.’