X-ray equipment for oil paintings and paper

Theresa Fairbanks-Harris <theresa.fairbanks-harris [at] yale__edu>
writes

>I was wondering if anyone has successfully used the same x-ray unit
>for both oil paintings and works on paper. ...

It is quite possible to use the same equipment to image paper as
long as it works c 15 kV. At the higher kVs often used for paintings
(between 30 to 45 kV??) the beam will hardly be absorbed by the
paper and if you get an image of the paper at all it will be very
low contrast.  At 15kV the film is best used unenclosed so that the
envelope does not absorb the beam.  If you have to enclose the film,
because you cannot black out the room where you have the X-ray
machine, you could try using the film in a black plastic bag
(polythene).  Do not use flexible black plastic film cassettes for
this as they are usually quite thick PVC and the chlorine in the
polymer will greatly attenuate a low kV beam.

This will give you an image of the paper (its structure, watermarks
etc.) but the kV you require to image the components of a work of
art on the paper will depend on what the pigments etc. are made from
and may be in the same range as for paintings on canvas. I can guide
you more if you provide details.

Dr Sonia O'Connor
Post-doctoral Research Fellow
University of Bradford
Bradford BD7 1DP
UK


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                  Conservation DistList Instance 24:45
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