A researcher at McMaster University in Hamilton is using nuclear technology to show what the eye cannot see in great artworks.

Brandi Lee MacDonald, a research associate at the university, and an international team of scientists, engineers, conservators and art historians are going below the surface of paintings using new technologies. They're looking at artists such as Van Gogh and Van der Neer, analyzing the composition to find what the human eye can't see.

"For me, the goal of the project was to explore the material history of paintings using a suite of different techniques in radiation physics," MacDonald said.

The painting called Portrait of a Man by an unknown Venetian artist as seen in (from left) visible light, X-radiograph, UV light and IRR imaging. (McMaster University)

Using nine paintings donated by the McMaster Museum of Art, the team is examining the art using non-invasive technologies. Those machines include X-ray fluorescence, infrared and neutron radiography.

So far, they've gotten better understandings of the paint's pigments, the grains of wood, and the painters' techniques.

Their most significant finding was underneath Van Gogh's Untitled, Still Life: Ginger Pot with Onions. MacDonald's team found what might be an abandoned painting underneath the work. Van Gogh was famously known to have recycled canvases for financial reasons, and this discovery furthers those thoughts, a news release said.

"Some of these paintings are more than 300 years old and we are untangling some fascinating information," said Carol Podedworny, director and curator at the museum. "Every time Brandi would come close to a painting with her mobile XRF machine we would freak out."

One of the nine paintings donated by the McMaster Museum of Art is analyzed using microscopy. (McMaster University)

They weren't alone.

"It was nerve-wracking," MacDonald said. "Putting a Van Gogh in the core of a nuclear reactor is not something that is taken very lightly."

This idea stretches all the way back to 2010 when MacDonald, who specializes in pigment analysis, saw the potential in using sophisticated, non-invasive techniques in analyzing art.

Now, her team's findings are being shown to the public. An exhibit has been opened at the museum titled The Unvarnished Truth highlighting the discoveries.