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Highlights in Chemical Technology

Chemical technology news from across RSC Publishing.

Interview: Chemical conservation

18 September 2007

David Saunders explains to Joanne Thomson how chemistry can be used to preserve ancient artefacts:

David SaundersDavid Saunders is Keeper of the Department of Conservation, Documentation and Science at the British Museum, London. His research focuses on the scientific examination of artefacts, principally using non-destructive imaging and spectroscopic techniques.

What inspired you to develop a career in the analytical sciences?
I was inspired to specialise in chemistry by a teacher at school whose enthusiasm for the subject caught my imagination. I have also had a longstanding interest in museums since my father took me to them as a child.

When I was coming to the end of my postgraduate studies, I was very interested in the way that science is applied to the arts and archaeology. When I was doing post doctoral work, I saw a job opportunity at the National Gallery in London and that was really how I started in the field.

History and not chemistry springs to mind when most people think of museums. How big a role does chemistry play at the British Museum?
Chemistry is involved in two aspects of the museums activities. Firstly, it is used in the preservation and restoration of the collections. Secondly, through the chemical analysis of the objects, we bring another aspect into their interpretation that augments the history side. We can shed light on how objects were made, what they're made of and how cultures have changed, developed and traded. Increasingly we're finding the public are engaged by this type of information.

However, chemistry is obviously only one of the sciences that we use. At the beginning of the 20th century, many people involved in the study of museum objects were physicists. As the 20th century progressed, chemistry became more and more important, especially for the understanding of deterioration processes, but I think it has now broadened out again. We use many different scientific disciplines, including some of the newer ones like nanotechnology.

What techniques do you use to examine artefacts?
We begin by using simple microscopy to magnify an object. We then use scanning electron microscopy (SEM) to look at objects at much higher magnification. With this we have the potential to conduct energy dispersive X-ray analysis (SEM-EDX), which is an absolute workhorse for the department. This can give us some elemental information.

We also use other X-ray techniques like X-ray fluorescence and diffraction and X-radiography. X-radiography is very important - we use it routinely to look inside objects that we can't otherwise look in.

We use various spectroscopic techniques, including Raman spectroscopy. This has been the big new thing for museums in the last 10-15 years, particularly Raman microscopy, where the Raman is directed through the optics of a microscope. The fingerprinting of various materials by Raman has become of sufficient significance that the organisation that was putting together the infrared library of museum-related materials has extended it into Raman.

What is the most rewarding aspect of your work?
It's adding to the sum total of something that's known about an object. Preservation is, of course, enormously important but it is the intellectual enquiry that I find most rewarding. I enjoy using the documentary sources together with the knowledge of specialist art historians and archaeologists to piece together what the science is telling us about the object with what we know about the object from other sources.

Do you have a message for young scientists?
Don't get too narrow. Read around; look at what is happening in other fields. You can't be an expert in everything but you can have a broader knowledge and that's when you start to see the interconnections. Bringing in the best of other fields is a terribly important facet of how scientists can think within an organisation.

Which scientist do you most admire and why?
Michael Faraday, because he was heavily involved in the development of science in museums and galleries in Britain. Everyone knows Faraday for his very straight scientific work but he got involved in everything. He was involved in the commission that looked at relocating museums out of London in the mid-19th century because of fears about pollution damage to the collections. Although he was engaged in very serious study in a single area, it didn't stop him retaining that breadth.

If you weren't a scientist, what would you be?
I have always regretted giving up history at such an early stage. I would quite like to be a historian. If I couldn't give up the science completely, perhaps I'd end up doing history of science. Maybe I would go the whole way and become an art historian or an archaeologist, although the idea of being knee deep in mud in an archaeological site doesn't necessarily appeal!

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