“For a long time, the art world wanted black artists to do black subject matter,” the collector Pamela J. Joyner has said. “People were viewed as not part of the struggle if they were doing abstraction.” The landmark exhibition “Solidary & Solitary,” based on the collection built by Joyner and her husband Alfred J. Giuffrida, spotlights abstract work by black artists of the 1940s to the present day. When the exhibition arrives in Baltimore, it expands by 80 pieces and acquires a new title: “Generations: A History of Black Abstract Art.” —L.J.