For Art's Sake

     

Preserving the world's masterpieces with science.

Art and Science
 
Something was wrong with the painting. The face was discoloured; the shadows slightly misplaced. Beneath the surface, a century-old secret was hiding. Painted in 1876, Edgar Degas’ Portrait of a Woman is a striking example of French Impressionism. It’s also an intriguing success story for science.
 
Observers first noticed that something wasn’t quite right with the shadowy, black-clothed subject of Degas’ painting back in the 1920s, but it wasn’t until 2016 that intrepid scientists finally solved the mystery.
 
To work out what was going on with the Degas portrait, scientists needed to explore beneath the surface layer of paint. And so they brought the artwork to the Australian synchrotron, where X-ray beams were used to penetrate through the material. Using a non-invasive technique known as X-ray Fluorescence Microscopy, they were able to identify the elemental make-up of the painting and thus reconstruct what lay beneath.

Emma Dobigny hidden by a new painting
It revealed that the mysterious presence behind Portrait of a Woman was Emma Dobigny, a 19th century model and one of Degas’ favourite subjects. The painter clearly hadn’t been satisfied with this particular rendition of Dobigny, for he had painted over the draft and created a new work of art with an entirely different woman as its subject – the likeness of whom remains forever preserved in the portrait we now see today.
 
Degas may have thought that his decision to paint over Dobigny was the end of things and that no-one would ever know of his abandoned portrait. But as the years went by, the oil paint on his canvas thinned, once again revealing the nebulous outline of Dobigny in the form of a stain on the other woman’s right check. For years, the original subject remained hidden, and she would have to wait until the 21st century to reappear again with the help of pioneering science.
 
As technology advances, we’re able to learn more about and better conserve the masterpieces of years past. Time is not a natural friend to art. The cumulative effect of environment and wear can erode the materials on which masterpieces are produced, threatening the existence of these cultural treasures. Degas was not alone in choosing to paint over his failed attempts. Many others used this practice to save money on costly materials. Then as now, new canvas rarely came cheap.
 
 
Paint and Science
 
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.

 

Read more about cutting edge research in Diamond's popular science magazine:

 

 

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