I remember turning around in the Musée d’Orsay in Paris and unexpectedly coming face-to-profile with “Whistler’s Mother,” a painting I thought would be residing in the United States. But there it was amongst a wealth of French paintings, frame after frame of the greatest hits from the impressionist and post-impressionist periods. The museum is undergoing a renovation and selections from the collection are on two tours, both stopping in San Francisco.  Right now, the de Young Museum is hosting “Birth of Impressionism” through September 6th.  Soon after, the post-impressionists get their turn. It’s “a masterpiece everywhere you turn”, and Whistler’s mom gets to see her home country.