yes, they have masterpieces that are not on display. They have a HUGE collection of Rembrandt etchings [[I think it is the largest in the country, and yes, they are contemporaneous and not later imprints) They regularly have Van Gogh's self portrait and Postman Roulin on display, but they have at least two others that are not, they have 7 Rodin's, of which only Eve and The Thinker are regulars
Bookmarks