Don’t tell Centre College graduate Greg Smith that art and science don’t mix, especially in his Conservation Science Laboratory at the Indianapolis Museum of Art (IMA), where he is the director and Otto N. Frenzel III Senior Conservation Scientist.

“Science and art have always shared a rich interface,” he says. “The restoration and safeguarding of our collections is just as much a question of chemistry as it is of art history or aesthetics.”

Jeff Fieberg, Centre College’s newly appointed John C. Walkup Professor of Chemistry, shares the same philosophy. Although a chemist by training, he discovered his love of art while studying in Europe his senior year.

“I had never studied painting until Centre humanities classes,” Fieberg says. “Under [music professor] Barbara Hall’s tutelage, I thought, ‘Wow I really like this.’ During winter term my senior year, I studied with Bob Weaver, the music professor, in Paris, Florence, Munich, and Amsterdam. He taught one course on music, the other on art and architecture. That experience was transformative.”

Now Fieberg blends his two passions, performing technical and historical investigations of modernist paintings and analyses of artists’ materials.

During his 2011-12 sabbatical, Fieberg was working in Smith’s lab, using spectroscopy (the study of the interaction between matter and light) to analyze paintings, when serendipity presented the scientists with Vincent van Gogh’s Undergrowth with Two Figures from the Cincinnati Art Museum. The 1890 post-Impressionist painting depicts a peaceful scene of a couple walking between two rows of trees and hundreds of flowers.

But all was not as it seemed.

A 1974 conservation treatment had left the painting coated with thin layers of wax and varnish which, over decades, had turned milky white and obscured Van Gogh’s signature brushwork and use of color.

During the museum conservator’s meticulous restoration process, he found minute, hot pink paint fragments embedded in the wax that didn’t match any portion of the painting. What pink features originally existed in the painting? What was the identity of this pigment?

Smith and Fieberg were called in to find the answers. Using x-ray and laser spectroscopy techniques, the team examined 387 of the white flowers. They discovered that Van Gogh had used the pink pigment “geranium lake,” one of the many new synthetic colorants that chemists were inventing toward the end of the 19th century.

The key to discovering the lost pink flowers was in the element bromine, an unusual addition to artists’ materials that occurred only in geranium lake pigment during Van Gogh’s time. Using non-destructive x-ray analysis to locate the residual bromine, the telltale pigment was found in 38 percent of the now-white flowers—which used to be pink—and also in some now-blue tree trunks that Van Gogh described in his day as “violet.”

The discovery was critical because with the original colors the viewer’s eye travels around the painting differently and creates different interpretations and emotions than in its current state.

“We consider Van Gogh to be a master of color, and yet we are learning that because of material choices he made, what we see today is not an accurate representation of his artwork,” says Smith.

So the two scientists set out to digitally reconstruct the color scheme that Van Gogh originally envisioned.

“We determined the correct color coordinates and then injected the pink color back into the flowers in the digital rendition. It looks more like it would have when Van Gogh painted it,” says Fieberg.

The new “painting” regularly receives accolades when Fieberg and Smith present their findings to both academic and public audiences in the U.S. and abroad.

“The reception is always the same—wonder and excitement about the interplay of high-tech science and beautiful artworks,” says Smith.

The journal Applied Spectroscopy made their article, ‘‘Paintings Fade Like Flowers’’ (written with co-authors Per Knutås of the Cleveland Museum of Art and Kurt Hostettler of the Indianapolis Museum of Art), its featured paper in April.

As two-time director of the Centre-in-Strasbourg program, Fieberg has used such publicity to secure unforgettable opportunities for Centre students to visit conservation labs at the Louvre, in Marseille, and in Avignon. And during the three-week CentreTerm, Fieberg teaches “Molecular Modernism: Manet to Matisse” as a travel course in Paris and southern France.

He credits Centre study-abroad opportunities as life-changing for both Smith (Strasbourg, London) and him.

“I take students to the town of Auvers-sur-Oise, where Van Gogh lived when he painted Undergrowth with Two Figures, to the wheat fields where he shot himself, and to his grave. Students then realize they are studying real people,” says Fieberg.

“It’s one of the most powerful parts of my program.”

The two plan to continue their collaboration when Fieberg returns to the IMA lab during his 2018 sabbatical. They are hoping to investigate another of Van Gogh’s works, as well as works by Gaugin and others from the same time period who could also have used the disappearing pink pigment.

Like his paintings, Van Gogh’s life faded too soon. Thankfully, through science, Fieberg and Smith can restore the bright colors of Van Gogh’s art.