Using A Digital Light Projector To Restore Mark Rothko Paintings
One of the coolest talks I saw at the ICOM-CC conference in Lisbon last week came from Jens Stenger, a conservation scientist at the Harvard Art Museums in Boston. He had the tricky task of figuring out what to do about five paintings by Mark Rothko in the museum’s collection that were so damaged from sunlight exposure that crimson paint on the canvas had turned to blue.
If just a tiny corner of the paintings were light damaged, museum staff might have considered retouching the artwork with a little paint. But a massive fraction of the massive panels were seriously light-damaged.
And these days the trend in art conservation is to minimize interventions on art, especially contemporary art. So a team of curators, conservators and scientists decided that, “repainting was NOT the way to go,” Stenger said.
But everyone thought museum visitors would want to know how the artwork had looked before the light damage. So what to do?
The solution Stenger came up with is pretty cool: Figure out the exact coloration of the originals. Display the artwork as is, but set up a digital light projector that can cast an image on to the canvases. This projected image temporarily makes the paintings appear as they did when Rothko finished them in 1963. Switch off the projector and the paintings are returned to their current-day states. It’s effectively restoration with an undo button. (And as an aside, the amount of light delivered by the projector is not sufficient to continue to harm the painting.)
But like most things in life, this seemingly simple solution took a lot of work.
First off, Stenger wanted to know more about why the paintings had faded so dramatically. In 1988 Paul Whitmore reported that the fading crimson red paint in the Rothko paintings had been a synthetic pigment called Lithol red mixed in with a bit of ultramarine blue. Lithol red is a problematic pigment to begin with, Stenger said, but the fading due to the excessive sunlight exposure was probably exacerbated by the fact that Rothko mixed the red with ultramarine blue. It turns out ultramarine blue can also catalyze bleaching of Lithol red.
Next up, Stenger looked for photographs of the original paintings, so that the team knew exactly the colors in the painting before fading. This way they could project the right color of light on to the old canvases.
Luckily, color film ektachrome images of the Rothko canvases had been taken in 1963, Stenger said. The bad news is that some of the blue pigments in the ektachromes had faded, distorting the colors in the ektachrome image so that they appeared too red.
At this point I might have gone home, curled up and taken a very long nap.
Instead, Stenger got in touch with Rudolph Gschwind at the University of Basel. Gschwind has developed mathematical models for the fading of ektachrome images. From these models it's possible to work backwards to figure out the exact colors of the ektachrome images before they faded, and thus the correct coloring of the original Rothko paintings.
With the exact colors of the originals in hand, Stenger began working with the Camera Culture group at MIT's Media Lab to develop software that determines exactly what frequencies of light are needed to project onto the Rothko canvas so that they timewarp back to 1963. This is pretty tricky, as the software has to account for the color of the current canvas, as well as the color of the ambient light.
Anyway, it seems that the team has got the solution working. This new digital restoration will be on display at the Harvard Art Gallery within the next year or so. I can’t wait to check it out.
Different versions of the same painting. Left: the Rothko painting in its faded form. Middle: The ektachrome photo that had turned too red with time. Right: The painting color-corrected back to 1963. (Apologies for the distorted shot. I was sitting off-center from the PPT projection.)