The Girl with a Pearl Earring, a famous painting by Johannes Vermeer, was object of research in March. Scientists from all over the world got the opportunity to try out their techniques on the ‘Mona Lisa of the North’.
For two weeks straight, day and night, a room in the Mauritshuis (The Hague) was turned into a real laboratory. Inside a heavily secured glass cage, researchers from several institutes including the National Gallery of Art Washington, the University of Antwerp and the Rijksmuseum in Amsterdam scanned ‘the Girl’. As the Girl was originally painted in Delft, TU Delft could not miss out on this unique opportunity.
TU researchers from three faculties scanned the painting: Mathijs van Hengstum (Mechanical Engineering) made a special scanner to map the cracks on the painting; Tom Callewaert (Applied Sciences) used optical coherence tomography to scan the translucent layers; and Willemijn Elkhuizen and Tessa Essers (Industrial Design) measured the gloss variations of the painting.
Has this ever been done before?
The last time ‘the Girl’ received this much attention was in 1994, when researchers used tools like X-ray and infrared light to scan the painting.
But why would anyone want to scan a painting so thoroughly? Not to discover what the painting’s origin was. No, the researchers had other reasons to examine the painting.
No lack of cracks
Mathijs van Hengstum made his scanner to map the craquelure of the painting. “This is useful because the craquelure of paint tells us a lot about the state of the painting,” he explains. “It allows us to measure how a painting degrades. For example, if we place a painting in a very light and very humid environment, we can determine the environment’s effects on the painting just by scanning the craquelure and seeing how it changes over time.”
Has this ever been done before? “This will be the first device that can actually measure the craquelure pattern of the entire painting,” he explains. “You have microscopes that can reach the required resolution but can’t scan the whole painting. This device can do both, so hopefully this will open a lot of doors in researching paintings’ environments.”
Not harmful for the painting
Using Optical Coherence Tomography (OCT), Tom Callewaert scanned the painting to find out more about the thickness and transparency of the glazes used. Using OCT, he created a 3D image of the structure of the painting. “There are several reasons why you need this information,” Callewaert says. “To my mind, the first and foremost is the fact that you can make well-informed decisions about conservation treatments. In the past, the best way to examine the condition of a painting was by taking real, physical cross sections. But this is undeniably harmful for the painting. OCT gives us a similar cross section, but is non-destructive.”
“Besides that, you can map much larger areas than the ones you could have mapped with the traditional cross section method. You get an image of the thicknesses, how they give the painting its appearance, and the origins of the materials used in those layers. For example, the background of the Girl is very dark, almost black. But, Vermeer intended it to be dark green.”
For sale: 3D replica of the painting
Callewaert scanned the painting over four nights when the museum was quiet as the vibrations of the visitors around the glass cage affected the measurements. On the last night, the Girl was also scanned by two other TU Delft researchers: Willemijn Elkhuizen and Tessa Essers. They scanned the colour, texture and gloss variations of the painting. They can now make a 3D replica of the painting with not only the picture, but also its structure and gloss.
“There are three main reasons why we do this,” explains Essers. “Good replicas mean that you can bring a collection together that would not have been possible with the real paintings because they may be scattered around the world in different museums, for example. Another reason is a more commercial one: you can finally have a realistic replica of the Girl with the Pearl Earring in your own house. And the last reason is that the museum stores all the data in its archive, so should anything happen to the painting, at least it still has a replica in the archive.”
After these two weeks, the famous painting might be the most examined portrait in the world. She’s now back in her own spot in the Mauritshuis. The results of the examinations will be published over the next few months and years.
- Read more about the Optical Coherence Tomography or the cracks on the blog of the Mauritshuis.
- The project was covered worldwide, for example by the New York Times and the BBC (video).
- See behind the scenes pictures of the TU researchers on the Instagram of the TU Delft.
Roos van Tongeren / Redacteur
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