 It marks a major stylistic advance in contemporary portraiture; the girl is set in an airy, three-dimensional, realistic setting, and stares out at the viewer with a complicated expression that is reserved, yet intelligent and alert.It is widely regarded as one of the most exquisite portraits of the Northern Renaissance.Art historian Joel Upton described the sitter as resembling "a polished pearl, almost opalescent, lying on a cushion of black velvet."