“Landscape With Rainbow” (1859) by Robert Duncanson   SPEAKING TO BRIGHTER HORIZONS, a painting by Robert Duncanson played a special role in the Presidential Inauguration activities yesterday. “Landscape With Rainbow” (1859) was displayed in the U.S. Capitol Rotunda, on loan for one day from the Smithsonian American Art Museum (SAAM). Duncanson is the first Black...