A ‘pigment’ of the imagination: Color science and art

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Susan Stanger

Color scientist Roy Berns uses a spectrophotometer to measure pigment changes on Vincent van Gogh’s The Bedroom at the Van Gogh Museum in Amsterdam.

The Bedroom was a mess.

Layers of varnish had yellowed and patches of retouched pigment no longer matched; Vincent van Gogh’s famous painting needed a deep cleaning.

During 2010, the conservation staff at the Van Gogh Museum in Amsterdam began a yearlong restoration of the painting that would culminate in the 2011 exhibition “Bedroom Secrets.” Color scientist Roy Berns contributed to the project that restored van Gogh’s crisp, bright pigments.

Berns is the Richard S. Hunter Professor in Color Science, Appearance and Technology, and director of the Munsell Color Science Laboratory at RIT. His reputation for applying imaging and color science to art conservation has given him entrée into the back rooms of museums and among the community of professionals who labor like surgeons over famous artwork.

Conservators in Amsterdam gave Berns two tasks. First, to determine whether the retouched areas had faded or if the overall painting had continued to pale under the varnish. Berns traced the deterioration to the painting itself and determined the best set of restoration paints to ensure retouched areas would match under all lighting conditions.

Berns’ second challenge was to digitally simulate how the painting might have looked when the artist set down his brush in 1888.

“The color change was dramatic,” Berns says. “We brought back the colors that van Gogh described to Paul Gauguin as ‘walls of pale violet . . . the doors lilac.’

“The image processing included recovering the now colorless geranium red lake, darkened chrome yellow and testing recent models of varnish aging and its effect on the appearance of easel paintings,” Berns explains.

Sticking with van Gogh, Berns is applying his imaging techniques on Starry Night at the Museum of Modern Art. This spring, Berns will repeat color measurements he made in 2006, using a new spectral camera system.

In January, Berns’ research team measured the painting with a system they developed to analyze gloss and topography. A narrow beam of light travels horizontally, then vertically, as the camera takes pictures in a two-millimeter creep across the canvas. They use the hundreds of images captured to mathematically derive information about the painting’s gloss and topography. Compiling the properties of appearance gives depth to the two-dimensional surface and turns Starry Night into a three-dimensional image on a display screen.

Unlike The Bedroom, Starry Night is not a compromised painting in need of restoration; rather, it’s a favorite of Berns.

Berns has used his camera system to take the three-dimensional signatures of paintings by Pollack, Mondrian and Magritte that have happened to be sitting on easels in the studio during his visits to the museum.