Restoring artworks in Valencia (Spain) with bacteria

I’m glad to see this follow up to a post (my June 7, 2011 posting) which featured research on using bacteria to benefit art restoration in Spain. Maria Mocerino’s September 30, 2024 article for Interesting Engineering provides the update,

A mother [Pilar Roig] and daughter have teamed up to restore frescos in Valencia’s Santos Juanes church using bacteria.

When her mother ran into trouble with a restoration project in Spain, Pilar Bosch, her daughter, a microbiologist, found an old paper on the application of bacteria in art restoration.

As a microbiologist, she was only searching for a subject for PhD, but her mother’s troubles restoring 18th-century paintings in Santos Juanes church made her take a closer look.

The restoration project in Valencia faced particular challenges. A botched effort in the 1960s damaged the priceless artwork even further, leaving behind a layer of glue made of animal collagen, according to the Beijing Times.

Having found a lead that could benefit her mother’s work and a historical and cultural landmark, science and art joined forces in a 4-million-euro initiative to apply this technique. And it worked.

Here’s more about the project along with some technical details, from my June 7, 2011 posting,

Here’s the background on the problem the art restorers were trying to fix (from the news item),

The project came about when the IRP [Institute of Heritage Restoration] was in the process of restoring the murals of the Church of Santos Juanes that were virtually destroyed after a fire in 1936 and were improperly restored in the 1960s. The researchers tested new techniques for filling with transferred printed digital images in spaces without painting, but had great difficulty dealing with salt efflorescence, the white scabs caused by the build up of crystallized salts and the enormous amount of gelatine glue remaining on the pulled-off murals.

With the problem defined, the researchers then investigated a technique developed in Italy that looked promising (from the news item),

Therefore, Rosa María Montes and Pilar Bosch travelled to Italy to learn from the authors about the pioneering studies that used bacteria to remove hardened glue that was very difficult to treat with conventional methods.

The restoration of the Campo Santo di Pisa wall paintings was performed under the direction of Gianluiggi Colalucci, restorer of the Sistine Chapel, and his colleagues Donatella Zari and Carlo Giantomassi who applied the technique developed by microbiologist Giancarlo Ranalli. The researcher had also been testing with black crusts that appear on sculptures and artistic monuments.

The team returned to Spain to practice the technique and add some refinements (from the news item),

Back in Valencia, the multidisciplinary team perfected this method and trained the most suitable strain of Pseudomonas bacteria to literally eat the saline efflorescence found in the lunettes of the vault behind which pigeons nest.

“By the action of gravity and evaporation, the salts of organic matter in decomposition migrate to the paintings and produce a white crust hiding the work of art and sometimes can also cause the loose of the painting layer” says Pilar Bosch.

These scientists have managed to reduce the application time, and have also innovated in the way of extending the bacteria. According to Dr. Bosch: “In Italy they use cotton wool to apply the micro-organisms. We, however, have developed a gel that acts on the surface, which prevents moisture from penetrating deep into the material and causing new problems.

“After an hour and a half, we remove the gel with the bacteria. The surface is then cleaned and dried.” Without a wet environment, the remaining bacteria die.

13 years! Brava to the two Pilars!

A Reuters article (September 27, 2024 by Horaci Garcia and Eva Manez) was the basis for most of the other articles about the two Pilars and their project that you’ll find on an internet search; you can find the Reuters article here.

You can find listings for (and possibly get access to) Pilar Bosch-Roig’s (also known as, Pilar Bosch) research publications on her ResearchGate profile page or on her Loop Frontiers profile page.

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