Micropia samples living bacteria on Rembrandt's Night Watch

Micropia, the microbe museum of Artis zoo in Amsterdam, is sampling the bacteria and fungi living on Rembrandt's Night Watch at the Rijksmuseum. Microbiologist Eline van Bloois is working on the scaffold with Rijksmuseum restorer Esther van Duijn.

Van Duijn presses cellulose filters, small paper discs, against ten spots on the canvas each time, including the nose of Frans Banninck Cocq and the little dog and drum at bottom right. The samples are grown in culture and identified. A control sample checks that the microbes come from the painting and not from the sampling.

The work runs alongside the restoration of the painting, part of the Rijksmuseum's Operatie Nachtwacht, which also includes scientific research. Visitors can follow the restoration behind glass.

A replica of the Night Watch is on show in Micropia, showing which species sits on which part of the canvas. The project is called "The Night Watch is alive" (The Night Watch lives). The visible colonies are to be exhibited there as well.

Van Bloois says she has so far found no species that could harm the painting, such as some fungi. Most are bacteria that also live in the human body, plus soil microbes.

Project leader Karlien Pijnenborg, head of the Artis museums, calls it partly a crazy experiment and a bit of a marketing stunt. The aim, she says, is to make invisible life visible. A single sample would have shown little, she says, because each part of the painting can have its own microbes.