Flour paste. Wax resin. Synthetic adhesive. All have been used, over time, to attach an old canvas to a new one in order to conserve a painting.
There have been issues with all of those materials, so in recent years, University of Akron researchers worked to improve conservators’ bonding options. Their success has led to a new formulation of a synthetic adhesive that’s now the standard for conservators worldwide.
Why did they need to? Because flour paste dries out. Wax resin can penetrate artwork and change its color. The synthetic adhesive, created in the 1970s, wasn’t up to par after 2007 when one of the ingredients in Berger Ethylene Vinyl Acetate, or BEVA 371, stopped being produced, said Dean Yoder with the Cleveland Museum of Art. An alternative had to be found.
The art community adjusted. Instead of the BEVA 371 solution, which was activated on a hot table, conservators used a formulation that required warming canvases to a higher temperature in order to make the substance tacky enough to stick two canvases together. But they were never really happy about it. It was a risk for heat-sensitive paintings, which could be damaged in the effort to save them.
Now, the new concoction is getting raves from the art conservation community. BEVA 371 Akron, developed with the help of the university, is comparable to that first adhesive — and experts in the art community believe it improves upon it.
“I know there’s a sense of relief,” said Chris McGlinchey, a research scholar at the Conservation Center at the Institute of Fine Arts at New York University, who directed the project.
What were researchers looking for in art conservation material?
There were a lot of tricks to finding the right formulation for the new adhesive, said Ali Dhinojwala, the Polymer Science and Polymer Engineering professor at the University of Akron who led the research.
It had to be sticky but not completely melted. It couldn’t permeate a canvas. And it had to be reversible, so when the new canvas deteriorated, the painting could be saved again.
Plus, the ingredients for the new formulation had to be commercially available — a new material would be no good if its components couldn’t be found.
“It can be quite challenging,” Dhinojwala said.
“You can see why it is exciting for us.”
Dhinojwala said he started with about five potential formulations then narrowed the group down to three based on what temperature it was activated at. He started making test strips of canvas. Was it sticky? How did the peeling process work? Samples went to more than a half-dozen museums where conservators could try the substances and offer feedback.
When there was a preference, more extensive testing helped solidify the formulation. Work was also done to make it more sustainable — while the original BEVA 371 was shipped in solvents or film, BEVA 371 Akron can also be shipped as a pellet and even as a fluffy, nonwoven fabric that can be applied to a canvas.
The research was funded by the Getty Foundation, which guaranteed the new formula wouldn’t be patented and would be made available to conservation groups. The intent wasn’t profit; it was access for people who need BEVA 371 Akron to ensure precious artworks sustain.
Dhinojwala said this type of work usually takes decades, but this new formulation was completed in four years. It’s now the only adhesive made for this type of conservation.
“It’s a big thing,” Dhinojwala said.
Dharamdeep Jain, who worked in roofing adhesives, completed his post-doc on the project. He said seeing the behind-the-scenes conservation efforts changed his perspective on how museums work.
“It’s just rewarding to know that we can help the community on a large scale,” he said.
First painting using new formulation is relined in Cleveland
As far as he knows, Yoder, the Lapis senior conservator of paintings and head of paintings conservation for the Cleveland Museum of Art, lined the first painting in the world using BEVA 371 Akron.
It was “A Scientist Seated at a Desk by Candlelight,” a 1755 oil painting by German artist Anna Dorothea Therbusch. He said the choice of art was fitting.
“It’s something where all the stars aligned and it was really special to be part of the entire process,” Yoder said. “It’s hugely gratifying to be part of a project with international implications.”
The process will allow the painting to again be viewable to the public. A work that has to be relined can no longer support itself, so cannot be displayed, said McGlinchey, with NYU.
The Cleveland art museum doesn’t reline paintings every day, Yoder said. But tears, rotting, mold or other issues can require a secondary support structure to guarantee a work will last. The formulation has to be reversible, Yoder said, which this one is.
With war in Ukraine and bombings across the Middle East, it’s likely that a lot of art has sustained damage, McGlinchey said. He expects BEVA 371 Akron to help treat a lot of those works, making them viewable again.
For the Therbusch piece, Yoder said he applied the adhesive to the lining canvas, then put the painting face-up on that canvas on top of a heated suction table with a perforated top. The table warmed them to about 150 degrees. He then put a membrane over the top to exert vacuum pressure that would bond the two canvases together.
McGlinchey said conservators who had used the original formulation found the adjusted, higher-heat alternative to be “a real pain in the neck.” In comparison, he said, it’s clear how great the lower heat-set window is.
Yoder agreed, saying the BEVA 371 Akron formulation is equal to or better than the original. It has good bonds at a low temperature, and since the tackiness of the adhesive increases gradually as the temperature rises, conservators have more control to choose the strength of the bond depending on the painting.
Putting Akron in the name
The reformulation project started when McGlinchey, who now lives in Cleveland Heights, reached out to Dhinojwala. McGlinchey said he’d known about the University of Akron’s polymer programs for a while — “They’re just really respected,” he said — and knew researchers there would be able to handle the project.
The result, he said, went beyond the scope of the grant “even beyond my expectations.”
By creating a nonwoven fabric version of the adhesive, Dhinojwala expanded the materials BEVA 371 Akron could be used on, like textiles. And the gossamer-like, stretchy material is ideal for connecting two non-flat surfaces, McGlinchey said.
“None of us have seen anything like that before,” he said of conservators.
McGlinchey said he hopes the university’s contribution to the project helps the polymer program get more notice.
Dhinojwala said in addition to people knowing Akron for tires and a certain basketball star, he’s optimistic that, in certain communities, it will be BEVA 371 Akron that puts the city on the map. And that, he said, is the value of research.
“Without innovation, I don’t think we can be successful as a university, as a region, as a country,” he said. “It keeps the edge of innovation alive.”
When people use BEVA 371 Akron, Dhinojwala wants them to tie it to the place where it was made.
“I wanted to make sure there was some Akron name on it,” Dhinojwala said. “People becoming aware of the polymer program, aware of the university … that’s more valuable than how many dollars we get on every kilogram.”