Dspite the small number of Leonardo da Vinci paintings there, they have never been studied with modern scientific instruments. So “the Universal Leonardo Project is being set up to coordinate the first scientific examination of all the artist’s paintings. Scholars are still unable to agree on which paintings should be attributed to Leonardo, with the number accepted by individual specialists varying from one dozen to two dozen. ‘Even the Mona Lisa has not been subjected to a sustained technical examination’.”