When painters attempted to hide previous works using layers of lead-based paint, they could not have known the long term chemical reactions that they had initiated. As time has gone on, traces of lead within their masterpieces have reacted with oils and risen up to the surface, leaving the painting tarnished by white blisters.
And these blisters are remarkably stubborn – restorers have found them impossible to remove because they just grow back. This is known as lead migration. But the art world has an ally in their fight to preserve these vulnerable paintings: cutting-edge science.
If we can track the migration of lead within the painting and uncover more about how the process works, it might be possible to prevent it.
Experts in the techniques required for this analysis, Andy Beale from University College London in collaboration with researchers from Diamond and the Rijksmuseum in Amsterdam, the Netherlands are at work trying to preserve the paintings of the Dutch artist, Rembrandt van Rijn.
Working on one of Diamond’s spectroscopy beamlines, I18, the group uses chemical tomography to image the composition of the artists’ paintings. In other words, they’ve created a three dimensional map of a tiny fragment of the painting. Whilst this fragment is about the same thickness of a human hair, it contains information on the different layers of paint used from the canvas right through to the surface! The scientists hope to learn exactly how the white blisters form and whether some sort of chemical intervention could counteract the process, thus saving these masterpieces.
The research is still in its early stages and it remains to be seen what we can do for these works and others like them. But the strange cases of the ghostly Degas portrait and the mysterious lead blisters are demonstrative of the growing interactions between science and art. When these two disparate disciplines come together, they can unlock secrets, spark ideas and preserve precious art works for generations to come.