Dirty Little Secrets

Extremophile molds are invading art museums and devouring their collections. Stigma and climate change have fueled their spread

- BY ELIZABETH ANNE BROWN | PHOTOGRAPHS BY TY STANGE

Rust-colored stains have been present on Leonardo da Vinci's most famous self-portrait, drawn in red chalk on paper, since at least the 1950s. Researchers have determined that the culprit is the xerophilic fungus Aspergillus halophilicus.

LAST SUMMER I POLLED THE GREAT ART HOUSES OF EUROPE with a seemingly straightforward question: Had they had any recent experiences with mold in their collections?Mold is a perennial scourge in museums that can disfigure and destroy art and artifacts.

To keep this microbial foe in check, institutions follow protocols designed to deter the familiar fungi that thrive in humid settings. But it seems a new front has opened in this long-standing battle. I'd recently heard rumblings that curators in my then home base of Denmark have been wrestling with perplexing infestations that seem to defy the normal rules of engagement. I wondered how pervasive the problem might be.

My survey did not make me popular. Some museums responded quickly—too quickly, perhaps, to have checked with their curators. Ten minutes after receiving my inquiry, the press office at the Uffizi Gallery in Florence assured me unequivocally that there was no mold at the Uffizi. The museum declined to connect me with the curatorial team or restoration department. Many institutions—the Louvre, the British Museum, the Musée d’Orsay—didn’t respond to my calls and emails at all. I eventually came to suspect the Vatican Museum had blocked my number.

Frustrating though it was, this is the reception I expected. Asking a curator if their museum has problems with mold is like asking if they have a sexually transmitted disease. It’s contagious, it’s taboo, and it carries the inevitable implication someone has done something naughty.