Partly in response to these accusations, the Musée d'Orsay, which holds the second version of the Gachet portrait as well as the other works originally owned by the doctor, held an exhibit in 1999 of his former collection. In addition to the paintings by Van Gogh and the other Post-Impressionist masters, the exhibition was accompanied by works of the elder and younger Gachet. Prior to the exhibition, the museum commissioned infrared, ultraviolet and chemical analysis of eight works each by Van Gogh, Cézanne, and the Gachets for comparison. The studies showed pigments on the Van Gogh paintings faded differently from the Gachet copies. It also emerged that the Gachet paintings were drawn with outlines and filled with paint, whereas the Van Gogh and Cézanne works were painted directly to canvas. Van Gogh also used the same rough canvas for all his paintings at Auvers, with the exception of "The Church at Auvers" (whose authenticity has never been questioned).