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.

close-up of paint


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.

painting being photographed
Monitoring of Panel Movement


Detail of Joint After Repair


Interferogram of Joint Movement


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