Every day at 4 p.m., visitors standing in the special exhibition gallery at the Harvard Art Museums in Cambridge, Mass., can watch as a suite of Mark Rothko murals age 50 years in an instant. In that moment, a digital light projector switches off and what was a cohesive series of painted panels, known collectively as the Harvard Murals, suddenly looks disjointed. A beautiful, plum-colored background fades to different hues and the ravages of light and time on a delicate painted surface stand out. In an impressive trompe-l’œil, the murals painted in the 1960s by the famed abstract expressionist suddenly lose their luster.
This trick of time is the result of an innovative conservation tool created by the Harvard Art Museums and the MIT Media Lab for a special exhibition called “Mark Rothko’s Harvard Murals,” on display through July. Rothko’s paintings had originally been commissioned for a penthouse dining room at Harvard’s Holyoke Center, designed by architect José Luis Sert from 1958 to 1965 (now the Richard A. and Susan F. Smith Campus Center). The murals hung there until they began to fade. In 1979, they were rolled, put into storage, and rarely seen by the public. That is, until now.
The paintings have been restored using a novel digital camera-projector system and customized software. Developed by a team of art historians, conservation scientists, and conservators, this use of light effectively erases the damage to the work. Jens Stenger, who worked on the project at Harvard but is now the associate conservation scientist for the Institute for the Preservation of Cultural Heritage at Yale University, says that using light as a conservation tool dates back to the 1980s. It is still considered rare, though, particularly as a color corrective technique in fine art. “This is the first project of its kind on paintings, as far as we know,” Stenger says.
When first considering how to conserve the murals, the curators and scientists had a challenge. Traditionally, paintings are restored using a painstaking reapplication of paint, among other things, but this was ruled out for the Rothko canvases. The artist blended his own paint using ingredients like animal glue, egg, and pigment in order to exact a specific impression. The different recipes created varied surface effects of matte and gloss and the artist never used a varnish, which could damage that subtlety. The beauty of a Rothko is in the painter’s mastery of surface: The delicate changes in color, texture, and paint stroke. Replicating that would be impossible. “Traditional conservation where you add paint would be irreversible,” Stenger says.
Five separate panels make up the Harvard Murals, and Rothko’s intent was that they work in tandem. (A sixth panel, which was never installed, resides in the Rothko family private collection.) “Rothko talked about creating an image,” Stenger explains. “The five paintings were meant to act as one unit.”
The damage to the paint over time destroyed that unifying effect, but since repainting the canvases was out of the question, the team considered a system that might recapture the original look without touching the surface. That’s what led them to using light.
The first step in conserving Rothko’s work was confirming how the paint on the original panels looked. This proved tricky. The team went to the archives at the Harvard Art Museums to examine 5-inch-by-7-inch Ektachrome images that had been taken in the early 1960s after the murals were installed. “Ironically, the images were faded as well,” Stenger says. “The reason is simply that the film at the time wasn’t stable. The cyan photographic die degrades in the dark. You can store it really well and it still degrades.”
The team took the images to Rudolf Gschwind, a professor and head of the Digital Humanities Lab at the University of Basel in Switzerland, who is a specialist in digitally restoring slide film. “He has a custom-made LED illumination scanner to measure dye concentrations in the photo emulsion of the film,” Stenger says. “We did a scan that resulted in dye concentrations pixel by pixel.”
After months of careful restoration to the slide film, the team felt certain that they had an accurate representation of the original color. Next, they had to find a way to create a compensation image that could be beamed onto the canvas so that the reflected light closely resembled the murals from 50 years ago. About a dozen photos were taken under different illumination conditions to generate that compensation image, according to Stenger. For each image, they analyzed, pixel by pixel, the calibration curves for each color channel—red, green, and blue. They then used a color-mixing matrix to characterize the interdependence of these channels. “We calculated the light for more than two million pixels that had to be put onto the canvas in order to create the appearance that we wanted,” Stenger says.
In addition to the digital light on the canvases, the team had to consider the ambient light in the gallery. Rothko hated the use of spotlights to illuminate his art and had very specific ideas of how he envisioned his work lit. In a letter written to a London gallery in 1961, Rothko explained his preference for gallery lighting: “The light, whether natural or artificial, should not be too strong: the pictures have their own inner light and if there is too much light, the color in the pictures washes out and a distortion of their look occurs. They should not be over-lit or romanticized by spots; this results in a distortion of their meaning. Above all, the entire picture should be evenly lighted and not too strongly.”
For the exhibition at the Harvard Art Museums, the curatorial team lit the walls and the room independently of the paintings at 50 lux. “We used light fixtures with two lenses and four shutters and a diffusing gel,” Stenger says. “We pieced together the light on the wall behind the murals and were able to illuminate rectangles that blend together,” without shining on the paintings themselves. The software that runs the digital projector takes the ambient light into consideration when calibrating how to shine light on the mural.
The decision to shut the lights off at 4 p.m. each day was one that the team debated for years, according to Stenger. “We constantly asked: How should we show the work? It was a hard decision. You want to respect the art. You don’t want this to be about a fancy conservation technique. It’s about the painting,” he says. “But on the other hand, we’re introducing this novel conservation tool. The projection and the way it’s installed now is so perfect that most people who come in the gallery can’t tell just by looking at the painting that the lights are on.”
Stenger visited the gallery recently to watch the 4 p.m. switch. “People are surprised because it’s so believable when the light is on. The change is dramatic.”
This special exhibition, with 38 works by Rothko including sketch studies of the Harvard Murals, remains on view through July 26.
Exhibition: Mark Rothko’s Harvard Murals, Harvard Art Museums, Cambridge, Mass.
Curatorial Team: Mary Schneider Enriquez, the Houghton associate curator of modern and contemporary art, Harvard Art Museums; in collaboration with Narayan Khandekar, senior conservation scientist, Straus Center for Conservation and Technical Studies, Harvard Art Museums; Carol Mancusi-Ungaro, director, Center for the Technical Study of Modern Art, Harvard Art Museums, and associate director for conservation and research, Whitney Museum of American Art
Research Coordinator: Christina Rosenberger, Center for the Technical Study of Modern Art, Harvard Art Museums
Conservation Scientist: Jens Stenger, Institute for the Preservation of Cultural Heritage, Yale University (formerly of the Straus Center for Conservation and Technical Studies, Harvard Art Museums)
Camera-Projector System and Software: Developed with Ramesh Raskar, associate professor of media arts and sciences, Massachusetts Institute of Technology (MIT), and head, MIT Media Lab’s Camera Culture Group
Digital Restoration of Ektachrome Transparencies: Rudolf Gschwind, professor and head, Digital Humanities Lab, University of Basel, Switzerland