X-radiography of paintings
Technical examination of paintings can provide information about materials and techniques used by artists. It may also reveal the extent of old damages on the painting now concealed by past restoration. Information of this kind can be extremely valuable to conservators when carrying out research before undertaking treatments on paintings. It can also supply important art historical facts that can identify artists, assist in dating and help to uncover forgeries. X-radiography is one technique which can reveal useful information. This technique can show the different elements of a painting, from the canvas or panel it is painted on to the top paint layer
The Wood Sawyers by Jean-François Millet in 1857
X-radiography of Jean-François Millet's painting The Wood Sawyers from the Victoria and Albert Museum's collection has unveiled an extraordinary discovery.
An infra-red reflectograph exposed the shape of a head abovethe left shoulder of the foremost figure. It is at right angles tothe right shoulder of the same figure. This is barely visible tothe naked eye.
An X-radiograph of the painting was taken and when the image was turned 90° left, parts of an underlying figure could be seen. The figure of La Republique was discovered (see the image below). Alfred Sensier, Millet's biographer, recorded the existence of this painting which depicted a figure representing the French Republic and was painted for the 1848 State Competition.
Millet's entry to the competition was unsuccessful and because he was short of money he reused the same canvas, adding strips of canvas to enlarge the size of the support. He then used this canvas for The Wood Sawyers.
Additions to the canvas
These additions can be seen in the X-radiograph along the top, bottom and left edges. The right edge of the painting has the original edge of La Republique which has been folded out and painted over. The dark holes are clearly visible in the X-radiograph, as are the dark lines showing the tears along the fold line probably caused when the original canvas was attached to the original stretcher.
Twilight: Landscape with tall trees and a female figure
by John-Baptiste-Camille Corot
Corot painted this composition on a wooden panel onto which a cradle had been attached. A cradle consists of vertical battens stuck to the back of the panel, through which horizontal battens are slid. This reduces the risk of the panel warping and provides additional support.
When the painting was examined, unusual wrinkling in the paint surface and strange, prominent drying cracks were noticed.
Closer inspection of the paint surface using a microscope showed that an underlying paint layer of a different colour had oozed through cracks in the paint surface (see image on the right).
This, coupled with the strange wrinkling of the surface, suggested that something appeared to be hidden underneath the visible layer, possibly another painting. X-radiography was carried out to further investigate this. The criss-cross pattern is the battens of the cradle.
The secret revealed
As with the Millet's The Wood Sawyers, the X-radiograph did, indeed, unveil another painting underneath the visible paint layer. It shows a cottage, a river flowing under a bridge and a seated figure in the lower right corner (see the image on the right).
Corot appears to have painted over an existing composition which had not yet fully dried. This caused drying cracks and wrinkling to appear in the paint surface. The underlying paint which had not fully dried protruded through these cracks.