A University of Connecticut alumnus’s work using NASA technology to reveal the hidden brush strokes of Leonardo da Vinci’s Mona Lisa del Gioconda is still considered revolutionary 26 years later.

In 1986 Ralph Bernstein, an expert in digital imaging and a 1956 UConn graduate, worked on a team that used NASA’s technologies to unveil the painting and allow art historians to see its initial brushstrokes.

Essentially, the team digitally enhanced the image on a computer and removed layers of paint until they were down to the artist’s beginning sketches.

Under the leadership of John Asmus, research physicist at the Institute for Pure and Applied Physical Sciences at the University of California, San Diego, Bernstein used the newest, most evolved technology of his time to process the painting at the IBM Palo Alto Scientific Center. 

The techniques were based on X-ray examination as X-rays could reveal any lead-based white pigments hidden by layers of paint, according to a 1986 New York Times article.

Until Bernstein’s team got to work on the Mona Lisa, the only other examination method had been with X-rays, according to the article.

The next, ahead-of-its-time technique was infrared scanning. This called for a painting to be illuminated by infrared lamps so that a section of the painting could be scanned by a vidicon camera. The camera converted the intensity of infrared light from each section to a number. The light was absorbed by underlying carbon-containing materials and was reflected by the painting’s canvas. A computer program would then piece together the image.

The “new” computerized digital enhancement used by Bernstein filtered out colors and sharpened images, according to the article. It was the same technique NASA used to view clear, crisp images of pictures sent to Earth from the Voyager.

Over time the Mona Lisa “has suffered from pigment discoloration, repeated protective varnishing of the painting, small cracking of the pigment due to temperature effects, and previous attempts at restoration,” Bernstein said in a statement supplied by UConn.

Bernstein fixed the colors and spatially filtered the painting to minimize cracking effects, Heidi Douglas, director of engineering alumni relations in UConn’s School of Engineering, said.

Image enhancement operations used to sharpen blurry images of planetary features like the rings of Saturn were also used on the Mona Lisa so analysts could study the painting in greater detail, according to a press release.

Results showed indications that there were other attempts at restoration and that the Mona Lisa once wore a necklace, Bernstein said.

Art Historian and UConn Adjunct Professor of English Mary Gallucci said the significance of the no-longer-there necklace comes down to fashion; Da Vinci wanted his work to be timeless and fashion trends fade.

“Not adorning her with jewelry may have been a choice he favored in order to avoid hard edges and unwanted glints—he strove, in his ‘sfumato’ mode, to soften all edges and make the transitions very gentle,” Gallucci suggested.

“Leonardo was a master of invention whose chemical formulas are of such perfectly thin consistency,” Gallucci said. But even as art history resurfaces, the Mona Lisa may and should remain a mystery for years to come, she said.

Bernstein will be joined by Gallucci for a discussion about the technology that revealed the necklace 3 p.m. Friday, June 1 at the University of Connecticut’s Union Theatre on the Storrs campus. The event is part of UConn’s Alumni Celebration weekend.

Bernstein, now a science and engineering consultant, spent 36 years at IBM. For his demonstration of the feasibility and accuracy of digitally processing and correcting Landsat MSS and RBV data, he received the NASA Medal for Exceptional Scientific Achievement.