Leonardo da Vinci’s “The Last Supper” has survived since the late 1400s on a wall in the Santa Maria delle Grazie Church in Milan, weathering centuries of change and intrigue, such as a World War II bombing. Worried about soiling from air pollution in the city, one of Western Europe’s most heavily polluted, curators installed a ventilation and filtration system to protect it in 2009. The system worked well at reducing levels of fine and coarse particulate matter within the church (according to a new study), which should save the painting from worst effects of air pollution.But a significant threat remains: fatty lipids and organic compounds, such as those emitted from the skin of the 1,000 people that visit the painting each day.
Researchers have decided to get personal with Mona Lisa–by irradiating her face. In a study recently published in Angewandte Chemie, researchers trucked around the Louvre to look at nine faces painted by Leonardo Da Vinci with a portable X-ray machine.
Their particular technique, as reported by the BBC, is called X-ray fluorescence (XRF) and is a way to uncover the layers of paint without damaging the paintings. By looking at this layering, they learned more about Da Vinci’s brush strokes and a technique called sfumato, which he used to hide transitions between dark and light areas and to create realistic shading.
The Da Vinci researchers aren’t the only X-ray art historians. Another recently published study looked at “Mayan blue”–a long lasting pigment made by the civilization that lived in Central American from 2500 BC to the 1600s.