It's a treat to get the chance to compare the two greatest colorists of the 20th century: Henri Matisse and Pierre Bonnard. New York's Metropolitan Museum of Art is showing the scintillating exhibit "Pierre Bonnard: the Late Still Lifes and Interiors" and a nearby hanging of Matisse’s Nice-period paintings from its permanent collection. In Philadelphia (coinciding with the astonishing “Cezanne and Beyond” show that features so many great Matisses), the Philadelphia Museum of Art has “Henri Matisse and Modern Art on the French Riviera,” featuring works by Matisse, Bonnard, and contemporaries.