View Photo Gallery: Six contemporary artists use drawing, loosely defined, to expand the notion of portraiture at the National Portrait Gallery.

The National Portrait Gallery’s “Drawing on the Edge” asks the question, what is a drawing? The work of the six artists in the portraiture exhibition is disparate enough — including watercolor, mixed-media painting, digital video and charcoal on Mylar — to expand the notion of draftsmanship beyond the most traditional sense of lines on a piece of paper.

Drawing on the Edge: In fact, there’s fiction on display

But it also asks another question: What is a portrait? Although most of the artists in the show use photographs as reference points, the portraits subtly question the concept of likeness and identity. Are we what we look like, or something more?