Chemists in Verona, Italy, found out recently what’s been happening in a Butler University Chemistry lab, and they’re very grateful.
Butler University Junior Ben Dawson, working with Chemistry Professor Anne Wilson during the summer of 2017, has replicated a pigment that matched a color called Juliet blue that the Italian chemists had discovered on historical artifacts.
“I think they’ll be excited that somebody’s actually making these,” Wilson said. “People have been talking about these pigments but not making them.”
The Italian scientists’ discovery of Juliet blue goes back to 2010. They laid out the problem in a paper they published: Their museum had placed several ancient flints, used for making arrowheads, in storage. They had put the flints in a drawer, on rubber mats to keep them from breaking. When they opened the drawer, they found that a chemical reaction had occurred. The flints, which were gray, had turned blue—a color the chemists would later call Juliet blue.
The chemists thought the color on the flints was derived from a volatile organic component that was coming from the rubber mats, and that the culprit was a stabilizer that’s added to keep the rubber from falling apart over time.
Dr. Greg Smith, the Otto N. Frenzel III Senior Conservation Scientist at the Indianapolis Museum of Art, read the Italians’ paper and gave a copy to Wilson, asking if she thought someone at Butler might want to try to figure out a synthesis for Juliet blue. She thought that would be a great summer project for a student, so she had Dawson try to make the pigment. She paid him with an annual grant the Chemistry Department receives from Eli Lilly and Company to do synthetic chemistry work.
“Initially, we were not having a lot of success” trying to re-create the chemical reaction that caused the discoloration, Wilson said. “Then Ben left out some things over the weekend, and some of his indicator plates had turned blue.”
To be specific: Juliet blue.
“It was a very happy accident,” Wilson said.
Dawson confirmed that the way this blue pigment occurred on the surface of the flints was probably due to a combination of air oxidation, coupled with contamination from the compound in the rubber mats. And he was able to make additional quantities of the pigment.
“It’s a beautiful blue,” Wilson said. “It looks very Disney. It’s beautiful. It’s a great blue. It’s a lot of fun to be doing this and to see these great colors.”
Although reproducing Juliet blue is essentially an academic exercise, Wilson said, it could have practical applications. Butler Chemistry professors and students have done several projects with the Indianapolis Museum of Art on artworks that have faded over the centuries. Perhaps, Wilson said, this summer’s finding could be a step in figuring out how to treat, and possibly restore, artifacts that have been damaged.
“It’s exciting when you get scientists from different areas together and they start talking and trading ideas,” she said. “I think we’re very fortunate to be this close to the lab at the IMA. I think we’re very fortunate to be able to try things.”