WASHINGTON When people first filed into the courtyard of the Smithsonian National Portrait Gallery on Monday morning, the stage before them was empty, save for two massive, rectangular objects draped in plain brown fabric.

An hour later, Michelle Obama and Amy Sherald, the artist the former first lady carefully selected to paint her official portrait, took the stage. Together, they tugged on one of the fabric coverings until it fell to the ground. The crowd gasped audibly when the larger-than-life painting appeared before them and then broke into enthusiastic applause.