Definition article

During World War II, in August of 1943, the launched a massive bombing campaign on Milan and its outskirts. The explosions and the ensuing fires killed over 700 people and destroyed many of the city’s most important buildings and monuments, including a significant portion of Santa Maria delle Grazie. Miraculously, the wall with the painting survived, probably because it had been shored up with sandbags and mattresses, but the roof of the refectory was blown off and the other walls were decimated. The Last Supper remained exposed to the elements, covered only with a tarp, for several months, until the refectory (the dining room of the monastery where the Last Supper was painted), was rebuilt and a team of restorers began working to preserve and restore the painting.

But Leonardo’s work was already in sad condition well before the bombs threatened to destroy it completely. Soon after it was completed on February 9, 1498, it began to deteriorate. Because Leonardo sought greater detail and luminosity than could be achieved with traditional fresco, he covered the wall with a double layer of dried plaster. Then, borrowing from panel painting, he added an undercoat of lead white to enhance the brightness of the oil and tempera that was applied on top. This experimental technique allowed for chromatic brilliance and extraordinary precision but because the painting is on a thin exterior wall, the effects of humidity were felt more keenly, and the paint failed to properly adhere to the wall. Mold grew between the paint and the surface, and the presence of moisture caused constant peeling. By the second half of the sixteenth century, Giovanni Paulo Lomazzo stated that “the painting is all ruined.” The first restoration efforts took place beginning in 1726, and over the centuries they were followed by several more.

Over the past five hundred years the painting’s condition has been seriously compromised by these early restoration efforts, as well as its location (the church is in an area prone to severe flooding), the materials and techniques Leonardo used, occupation by Napoleon’s army (who stabled their horses in the refectory and reportedly lobbed bricks at the apostles’ heads), humidity, dust, air pollution and, most recently, the effects of crowding tourists.

After the destruction wrought by the bombing in World War II, restorers covered the painting with a thick layer of shellac (a kind of resin) in order to combat the moisture problems and keep the paint from peeling. They then began scraping away some of the layers of paint that had been applied over the years, uncovering what they believed to be Leonardo’s original brushstrokes. Finally, in 1977, the Italian government and private corporations cooperated to fund a massive project to fully uncover the original painting. It took head restorer Pinin Brambilla Barcilon over twenty years to complete the effort, meticulously scraping away at the painting’s surface centimeter by centimeter with surgical tools and microscope. In 1999, when the fully restored painting—in its new, climate-controlled environment—was officially unveiled, critics around the globe argued as to whether it is now true to the original, or irrevocably deformed, as only about 42.5% of the surface is Leonardo’s work, 17.5% is lost, and the remaining 40% are the additions of previous restorers. (Most of this repainting is found in the wall hangings and the ceiling of the painting).

The Last Supper is a prime example of how public and professional attitudes toward restoration efforts are not only often contentious, but change over time. Whereas in the nineteenth century and earlier, restorations focused on overpainting in order to present the illusion of a perfectly finished work, modern approaches tend to favor the exposure of missing pieces, and to make all additions visible and explicit. The current version of the Last Supper resembles little of what Leonardo created in 1498, but it makes visible the painting’s miraculous and tortured history.