In the 1980s, the art conservator Raymond Lafontaine developed a new way to preserve paintings: He used light from slide projects to augment works that had faded. The technique came from “thinking about color perception,” Jens Stenger, a former conservation scientist in Harvard’s Straus Center for Conservation and Technical Studies, explains. “In human color perception you have a light source, a surface, and a viewer, and the three interact. If you can’t change the surface, you can change the light source to change the color.”
It was preservation, essentially, by way of optical illusion.
Since then, Lafontaine's method has been accomplished with digital projectors, which have been used to restore items like a tapestry of Henry VIII in England’s Hampton Court and a piece of Native American pottery housed at Purdue University. And Stenger has been using it to restore, pixel by pixel, a collection housed at Harvard: six murals by Mark Rothko, faded by time. A team at the university, with help from preservation scientists at MIT, shined light onto the murals, doing a pixel-by-pixel restoration of them.
So how do you do this kind of Rothko restoration? First, the team of conservators determined the materials Rothko had used in his murals—to understand, in turn, how they had faded. Then, they employed insights gleaned in the 1980s by Paul Whitmore, another Harvard conservation scientist, who had discovered that Rothko's crimson murals came from the artist's reliance on the light-sensitive pigment lithol red. Given his use of that pigment, and the conservators' desire to preserve his delicate brushwork, the team ruled out conventional restoration techniques. They needed, they realized, a solution that would preserve the painting without touching the painting. They needed something digital.