ANSA said Roberta Lapucci, conservation chief at Florence's SACI institute, has proposed in her article that the painter developed a firefly powder as a tool and converted his studio into something of a camera obscura.

The Italian news agency said that in studying Caravaggio's works, Lapucci discovered traces of photosensitive substances that react to light. She said the artist figured out how to use firefly powder to produce a short-lived, fluorescent image similar to a photograph, which he was then able to transform into a permanent sketch that eventually became a painting.