Two paintings named Saint Francis of Assisi Receiving the Stigmata in the Philadelphia Museum of Art and the Royal Museums of Turin have been re-examined by AI tests. The works are credited to the 15th-century artist Jan van Eyck. But Swiss company Art Recognition, working with Tilburg University, found no clear signs of Van Eyck's brushstrokes. The Philadelphia painting showed a "91% negative" result, and the Turin one "86% negative." Dr Till-Holger Borchert, a top Van Eyck scholar, said these findings back claims that both may be studio paintings made by Van Eyck's workshop, not the artist himself. Dr Carina Popovici, Art Recognition's CEO, said the negative results were surprising. She compared this to The Arnolfini Portrait, another Van Eyck work tested at "89% likely authentic." She added, "I’m guessing that the Philadelphia and Turin museums won’t be happy. It’s not good news on these paintings." Art historian Dr Noah Charney commented that such negative results are rare and led to more tests. He noted, "The negative results suggest that both of these pictures are studio works, which may mean that we have a lost original that was more fully by Van Eyck’s hand." Van Eyck is famed for perfecting oil painting with incredible detail. Yet fewer than 20 paintings are accepted as fully his. The National Gallery in London is planning a Van Eyck portrait exhibition this November. Art Recognition’s work also uncovered fake paintings on eBay and questioned the authenticity of other famous artworks, including a Rubens painting in the National Gallery.