In 1964, Rothko installed the murals on two facing walls of the penthouse dining room in Harvard’s Holyoke Center. He asked that special coverings be hung to shield the works from light from the floor-to-ceiling windows on the other two sides of the room. But the binder that Rothko mixed with his Lithol Red pigment, a color that was blended with Ultramarine Blue in all the backgrounds and that was also used in some of the color combinations of the vertical “figures,” made the paint highly unstable. The shades in the penthouse were rarely pulled because of the spectacular views of Boston, and excessive sunlight caused a radical and uneven fading of all the red. In 1979, the university removed the paintings, which have been exhibited only four times in the last 35 years.

“They had changed so significantly that in terms of art history they weren’t being discussed at all,” said Ms. Schneider Enriquez. “This exhibition hopes to bring them back to part of his whole career.”

The common conservation technique of “inpainting” — touching up areas of loss with new paint — was ruled out in the 1980s because of Rothko’s unconventional technique and the large expanses of damage. Narayan Khandekar, senior conservation scientist at Harvard’s Straus Center for Conservation and Technical Studies, described how Rothko created his translucent veils of color by mixing dry pigments with animal skin glue and whole egg that were absorbed into the unvarnished canvases. “Rothko created a very porous surface,” he said. “Typically when you restore a painting, you put a layer of isolation varnish on it to separate anything new from the original. But the moment you do that to a matte surface like this, you change the color values, you change the saturation.”