Joseph Padfield, David Saunders, John Cupitt and Robert Atkinson
Technical Bulletin Volume 23, 2002
Abstract
The history of x-radiography of paintings throughout the 20th century is summarised. Film type and exposure conditions used in recent years are detailed. Until recently, roughly A3-sized film was used, an internegative was made, and then the developed photographs were hand-assembled into a life-size X-ray mosaic. Now the processed films are scanned with a large flat-bed scanner and mosaicked with Virtual Instrument Presentation Software (VIPS). Plates have to be rotated, scaled, and translated by the software to correct for the finite thickness of a painting and the general unevenness of the paint film when X-ray plates are spread over it. The 'tie points' to match one plate to the next must be selected by a human operator, because of these geometrical distortions, as the mosaic is assembled. Software has been created to model the effect of a cradle on a panel and to give a mosaic uninterrupted by the secondary support. Other techniques for dealing with this are discussed.
Keywords
computer modelling, digitising, paintings, radiography, software
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Improvements in the Acquisition and Processing of X-ray Images of Paintings, Joseph Padfield, David Saunders, John Cupitt and Robert Atkinson (text-only RTF 0.15MB)
To cite this article we suggest using
Padfield, J., Saunders, D., Cupitt, J., Atkinson, R. 'Improvements in the Acquisition and Processing of X-ray Images of Paintings'. National Gallery Technical Bulletin Vol 23, pp 62–75.
http://www.nationalgallery.org.uk/technical-bulletin/padfield_saunders_cupitt_atkinson2002
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