The 17th-century Dutch painter Rembrandt van Rijn is so exalted that his name, like those of Michelangelo, Shakespeare and Tolstoy, is synonymous with the idea of genius in Western culture. The Cleveland Museum of Art's new exhibition wants you to slow down, to look closely and to grapple with factors that separate the master from his many followers, with whom his output was often confused by American collectors eager to own a piece of a legend.