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30 April 2020

Seeing the past: Caskets under X-Ray

Written by Graham Lampard, edited by Victoria Green

 

We’ve been talking a lot about secrets and discoveries recently as part of our #SecretsInLeather online exhibition, which has been serialised on social media for the last month. In February our Collections Assistant, Graham Lampard, began researching into our collections of caskets to see if they had any secrets to share. These caskets were used to store items of value, and would often be highly decorative with intricate ironwork and incised designs. The museum’s collection spans the 13th – 17th Centuries, with examples in varying conditions from all over Europe. Some remain locked and unexplored, the keys long lost. Some have received historic conservation treatments.

In partnership with Cranfield University, we were given the opportunity to take a closer look at these caskets, in order to better understand them. It was hoped that by using x-ray we would we able to see how the caskets were put together, whether all the components are original, and whether there was anything stored inside.

The object is scanned using the X-Ray.

An image is captured by the computer.

An image of the object can be viewed.

On the 6th February we drove to Cranfield University’s campus at the Defence Academy, Shrivenham, with eight of our caskets carefully packed in boxes. Dr. Fiona Brock had agreed that we could x-ray them to discover how they were constructed. The hope is to identify different construction methods and structures in caskets from different countries and periods. The portable x-ray machine is used by Cranfield in many areas of research including archaeology, medicine and dentistry. The same process as used in hospitals for broken bones, the x-ray scans the object and the image is captured by the computer.

One of the oldest items we have in our museum collection is a German love token casket from the 12/13th century. It is only the casket lid, however, that dates from that time. It is clear that there are two figures on each side of the lid, perhaps Adam and Eve or Tristan and Isolde (read more about this here). This casket came from the Benario Collection upon its dispersal in Berlin, 1927. We have not been able to find out much about the Benario Collection, or indeed about the casket itself. Figures aside, the decoration is otherwise very simplistic compared to other examples in our collection. Would an x-ray reveal any secrets? Well yes, actually! Images produced by the x-ray showed the internal structure of the lid, and it can clearly be seen that within the lid there some kind of padding under the embossed figures and a kind of honeycomb pattern, which may be the wood structure. Further investigation is needed to determine what this might be, or what this can tell us about the casket.

Another casket which we x-rayed was a rectangular forcer or strong box covered with tooled leather and elaborate protective ironwork. This casket is probably French, dating to the 15th Century. The x-rays clearly show the ironwork including the frilly edges and the nails within the wood, holding the iron to the box. We had been surprised to see that all the nails were bent inwards. It seems clear that this was a technique deliberately employed. The nails may have been put through, and then bent over with the inside subsequently covered in the thin leather to ‘hide’ the ironwork.

In addition to the x-ray, we were also lucky enough to have access to XRF analysis that day. This is a non-destructive technique which shows you the elemental composition of a material – in short, it tells you what something is made from. Having used this technology to examine our most decorative casket, we were in for another surprise. Our ‘Charles V’ casket can be dated to 1532 and likely belonged to Charles V, Holy Roman Emperor, or his wife, Isabella of Portugal (read more about this here and here). The casket itself is covered with vellum, overlaid with gold leaf, ornamented with incised designs and overlaid with tempera in red, blue and green. Analysis of the painted surface determined that what we had assumed was gold was, in fact, iron. Well mostly iron, with copper, lead, and traces of mercury. These ingredients must produce a ‘fool’s gold’ effect, to mimic real gilt. Why this might have been the case, we don’t know. Cost, perhaps? More research is needed to fully understand.

These discoveries may seem small, but understanding how our objects are put together satisfies more than just curiosity. These images will help to inform our handling and care of these objects and will be an aid to future conservation work. Exploration and analysis often raise more questions than answers and it is our role to search for the answers and share our knowledge with the public, one object at a time.

Museum of Leathercraft
Grosvenor Shopping Centre
Union Street
Northampton
NN1 2EW

01604 745681

info@museumofleathercraft.org