Reading the Hidden Secrets of Parchment

James Harrison from the EPSRC explains how modern scanning techniques have allowed us to read parchment too delicate to unroll...
16 May 2013

Interview with 

Dr Graham Davis, Queen Mary, University of London; Professor Tim Wess, Cardiff University


Dr Graham Davis - Queen Mary, University of London - So I'm not sure of the exact age of this scroll - it is actually a rolled up parchment so it didn't start life as a scroll but once it's rolled up as far as we're concerned it is a scroll, as far as the machine is concerned and all the technology we need to unravel it. I'm Graham Davis, Reader in 3D X-ray imaging, Institute of Dentistry at Queen Mary, University of London. I'm actually standing here at our third generation of scanner that we have developed here and this whole system here, this is obviously a lead lined enclosure, so once this door is closed there is going to be no x-ray leakage anywhere it is completely safe to sit here. James Harrison - Nowadays X-ray technology used to look beyond what we can normally see with the naked eye is a familiar procedure in medical diagnosis. Modern X-ray machines are now capable of creating three dimensional scans using X-ray computed tomography better known as CT scanning. Just as CT scanning has helped improve medical diagnosis, scientists are now proving its capability in the field of cultural heritage especially in helping to reveal the content of parchment documents which for hundreds of years have remained too delicate to unroll. Professor Tim Wess is from Cardiff University. Professor Tim Wess - Cardiff University - Parchment is skin, its dried skin that has been salted and limed and stretched and beaten and had hot water poured over it trying to make a smooth writing surface and so understanding how molecules behave over hundreds of years is something that interests me and parchment has been a fantastic vehicle to be able to study that. So working in that vein I then got more and more involved with samples where the documents had effectively turned from the collagen into gelatine and actually glued themselves together. Dr Graham Davis - Jim gave me a number of parchment samples and these weren't actually scrolls but we just rolled up a small piece put it in a container put it in the X-ray system and sure enough we could see the ink on it. Now we didn't have any means of unravelling it then but what we did have was some rendering software created at the Australia National University which would actually allow us to slice it and actually we could at least see writing that was on the inside of the scroll or on the outside of it. And it looked so good that when we sent it to Tim he thought this was some kind of mock up and we had to say to him that it was actually reconstructed from X-ray views of it and he was quite impressed then as were most people who had seen it so that's what really got the ball rolling. James Harrison - Once the first pioneering 3d scans were completed the school of computer science at Cardiff University used computer modelling to present a flattened view of the documents allowing a researcher to read what was on them, an exciting prospect for all concerned. Professor Tim Wess - The first time that I saw that done there is definitely, and it's one of those moments in your scientific career that sends shivers down your spine for the right reasons and you don't get that many of those in your career and seeing a flattened out document and we could all read it. And then handing that to the palaeographer who can then go an interpret that and say what the impact of that is in terms of history is a wonderful opportunity to have and it is great to be part of that chain. James Harrison - The moment clearly proved to be a significant turning point for historians and archivists and their ability to access historical information with literally thousands of historical documents locked away in archives the world over now available to the research community. Professor Tim Wess - The support that we got from archivists who said if this can be done then it would actually revolutionise the way in which archives and difficult to access documents at archives, you know history could be recovered from in a way that we don't actually know what some documents, the information on some documents we can have a guess at what they contain but if we can actually reveal that it once again resets the priorities of how we might store them. James Harrison - With funding from the Engineering and Physical Sciences Research Council this innovative use of X-rays and three dimensional micro tomography gives us an unparallel glimpse into our hidden past. And it's not just about simply detecting iron particles contained in medieval inks. What makes the technique stand out from other methods is the unprecedented high contrast resolution it provides to clearly distinguish between ink and parchment, meaning text is much clearer and therefore readable? The discovery has also proved beneficial back in the departments that first developed the technology in relation to the human eye for example high contrast X-ray micro tomography has the potential to help ophthalmologists investigate problems related to glaucoma while for Graham Davis and his colleagues at Queen Mary's Institute of Dentistry this enhanced scanning technique is helping advance aspects of dental research. Dr Graham Davis - As well as developing the new scanner we have made a number of improvements to existing scanners using our technology that we have developed here and that's already, where we are using that in dental research, to see things in teeth that we hadn't seen before and in fact we have just got a paper that has just been accepted now talking about high contrast X-ray micro tomography in dental research. James Harrison - Back in the domain of cultural heritage there are aspects of the new technology that still need to be improved. While the archive community has been excited by the prospect of at last being able to read inaccessible documents there are still several developments required to make the machine practical. Dr Graham Davis - The detector that we are using at the moment the CCD detector isn't the most efficient one it's not the fastest but it gives us the most accurate results and that's why we have stuck with that. When we've got that, when we've shown feasibility that we can do this then we start to think can we make it faster, can we make it portable so that we can transport this thing to museums or archives, those are the sort of things that will come in future projects but at this level it was rarely while asking the question could this be done or can't it we are on that narrow line between possibility and impossibility and I hope we are on the right side of that line.


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