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From electron microscopes to X-rays, high-tech tools expose low-tech art forgery


Icilio Federico Joni (1866-1946) was a masterful Italian artist of medieval paintings. Trained in the techniques of Middle Age artisans, Joni used his skills to legitimately restore 14th-century works. Then, he started forging them.

“As to beauty — they are lovely! But there are too many of them,” art historian Mary Berenson said of the fake medieval works of art cropping up in the early 1900s. (Nevertheless, her husband, Bernard, seemed to continue passing them off as genuine even after figuring out what Joni was up to.)

In 1951, donors gifted the Indianapolis Museum of Art with Madonna and Child, a 14th-century painting they’d purchased a few years earlier from an Italian art firm.

The gilded painting, depicting Mary in a blue robe holding a steady-gazed baby Jesus, hung in the museum until the 1990s. That’s when a curator, who’d recently attended a lecture about a prominent forger, noticed literal cracks in the painting’s facade.

After the painting had spent a few decades in storage, Greg Smith, the museum’s senior conservation scientist, decided to take a closer look at the suspected forgery.

“In our laboratory we have about one-and-a-half million dollars worth of scientific equipment and imaging systems, and so we threw all of that artwork in kind of a crescendoed approach,” he told Digital Trends. Glennis Rayermann, then a Ph.D student at the University of Washington, assisted with the project, attempting to figure out if the painting was indeed a fake and if Joni was responsible.

Mind the beeswax

In 2006, Kim Muir and Narayan Khandekar published a paper in the Journal of the American Institute for Conservation about the techniques they’d used to analyze a Joni painting. While the 20th-century artist was a restorer, anything he touched was suspect. As the researchers noted, the curator Gianni Mazzoni once said, “There was a time, around 1930, when the notoriety of Joni had grown to such a point that it conferred an air of uncertainty onto every gold ground painting that came from Sienese and Florentine antique shops.”

Greg Smith surveying painting
Dr. Gregory Smith, senior conservation scientist at the Indianapolis Museum of Art, uses a microscope to search for signs of forgery on a 17th century painting. Indianapolis Museum of Art

Using Muir and Khandekar’s paper as a template, Rayermann outlined a plan to analyze the Indianapolis museum painting from the ground up. “You do as much as you can at the beginning non-invasively, non-destructively,” she explained. That meant photography, X-rays, infrared, ultraviolet lights, and microscopes.

With the X-rays, she was “looking for the bones of the painting,” she said. Painted on wood panels, the Madonna and Child is made of two planks held together by four wooden joints. Other elements revealed by the X-ray, like the grain of the wood, the shape of the nails, and the placement of the fasteners, all appeared consistent with medieval manufacture. It’s not easy to assign those results to the “it’s not a fake” column, though. Joni learned these methods and would often use very old wood to make his forgeries look authentic.

“I have a couple inklings that what we’re seeing …. isn’t from the Middle Ages.”

One non-invasive method of aging wood is dendrochronology, like counting a tree’s rings. But the Joni painting is coated in beeswax, obscuring the telltale lines. It’s a centuries-old practice artists used to keep the wood from warping.  If only one side of the wood is painted, the back tends to swell over time, Smith explained.

“This could have been a trick that Joni did in order to try and prevent you from seeing the back of the wood, something that might give away the fact that this isn’t ancient,” Smith said, “Or he could have been doing it intentionally to try and mimic the technique.”

High(lighted) brow

The X-ray revealed details beyond just the painting’s construction. Rayermann describes the painting like a layer cake, and from the bottom up it’s stacked like this: the wood panels, the ground layer, the preparatory layer, the paint layers, and the surface. The x-ray didn’t skip over all of them and go straight to the wood. It showed the ghostly outlines of mother and child on the preparatory layer. The faces have no distinguishable features.