Reading the Unreadable


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, and 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, at the Institute of Dentistry, Queen Mary, University of London. I’m actually
standing by our third generation scanner that we have developed 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. 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.
Parchment is skin, its dried skin that has been salted and limed and stretched and beaten
and had hot water poured over it 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. 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 and 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 Australian 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, as were most people who had seen it, so that’s
what really got the ball rolling. 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. The first time that I saw a flattened out document that
we could all read it was one of those moments in your scientific career that sends shivers
down your spine for the right reasons. And then handing it to the palaeographer who can
then go and interpret it and say what the impact is in terms of history, is a wonderful
opportunity to have and it is great to be part of that chain. 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. 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 are stored. Sometimes we can only guess at
what documents contain but if we can actually reveal the contents it once again resets the
priorities of how we might store them. 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. 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. We are already using it in dental research,
to see things in teeth that we hadn’t seen before and in fact we have just got a paper
accepted about high contrast X-ray micro tomography in dental research. 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. 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 it. When we have the results, when we’ve shown feasibility
that we can do it, 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 really 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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