Conservation and Technology
Non Invasive Monitoring
Dr Christina Young
Using optical techniques it is possible to monitor the behaviour of paintings and measure their response to a variety of parameters without altering or damaging them. There are many related optical techniques that can be employed.
3D Electronic Speckle Pattern Interferometry is used at
The Courtauld because it is suitable for mapping the in-plane
and out-of-plane deformations of canvas and panel. Being
a non-contact, non-destructive technique ESPI enables better
use of the more rare examples of deteriorated paintings
that can be used for testing, and also offers the possibility
for monitoring paintings in the gallery.
The image on the right is a two dimensional strain contour plot of a canvas with tacks every 30mm.
A reference image is recorded, the painting deformed by tensioning and a second image recorded. The deformation of the surface is then calculated from the difference (auto correlation) between the two images. The deformation is then displayed as a 2D map in contours or pseudo-colour.