Paul Haner, paintings conservator at Saint Louis Art Museum, works to touch up a 15th century painting..

In this May 13, 2009 photo, Paul Haner, paintings conservator at Saint Louis Art Museum, works to touch up a 15th century painting by a follower of Rogier van der Weyden, in an area off limits to the public at the museum in St. Louis. The museum has decided to open a temporary exhibit beginning June 10 where a conservator will clean and touch up three 18th century Hubert Robert paintings. Museum patrons will be able to watch the work unfold and ask questions

In this May 13, 2009 photo, Paul Haner, paintings conservator at Saint Louis Art Museum, works to touch up a 15th century painting by a follower of Rogier van der Weyden, in an area off limits to the public at the museum in St. Louis. The museum has decided to open a temporary exhibit beginning June 10 where a conservator will clean and touch up three 18th century Hubert Robert paintings. Museum patrons will be able to watch the work unfold and ask questions