The enigma of ancient textile conservation deciphered
At first glance, the inexperienced eye passes without stopping. What could be the point of these more or less rigid and quite irregular crusts deposited on metal objects? Moreover, even the restorers of ancient objects have long eliminated them, too happy to restore copper to its former lustre. Yet, these pieces are real treasures, the last remains of textiles thousands of years old, saved from disappearance by mineralization. But what remains of the original fiber, its form, its composition? Has organic matter withstood the ravages of time? How, then, does what looks like fossilization take place? For a long time, these questions have mocked the curiosity of researchers, but after nearly ten years of research, a French team of archaeologists, art curators and chemists has lifted the veil on this mystery. The results have just been published in the Proceedings of the American Academy of Sciences (PNAS) of August 3.
As is often the case, this breakthrough was the result of a meeting between three scientists who share the same passion. Curator at the Louvre, archaeologist Ariane Thomas directs the collection s of Mesopotamian antiquities, a vast collection at the heart of which is hidden her secret garden: a few dozen small fragments of mineralized textiles.When I arrived at the Louvre ten years ago, no one had studied them,” she recalls. “I had done a thesis on Mesopotamian costume, based on cuneiform texts, and I had samples. They were degraded, but if you look closely, you can find valuable technical information on the manufacture and even the nature of the thread and its quality.
Ariane Thomas contacted her colleague Christophe Moulhérat, an art historian and archaeologist in charge of analysing the collections of the Musée du quai Branly, who also has an undisguised love of textiles. His thesis was devoted to Celtic samples, in particular wool remains from the first millennium BC.By combining scanning electron microscopy and metallographic cutting, he invented a method of identifying fabrics from their fossils. Cotton from Pakistan, domestic silk or wild silk from Mongolia, he multiplied his observations, creating a collection in the process. I wanted to understand how these fossils were made. But I didn’t have the scientific competence. I contacted Loïc Bertrand.”