Did you know what artwork that detail is from? You can see the
answer here below: Rembrandt, Self-Portrait, Drawing at a Window, 1648 (The Rembrandt House Museum, Amsterdam).
In this last etched self-portrait Rembrandt made we see the artist
sitting at the window in his working clothes. From the slope of the
working surface and the way in which he grasps the tool it would seem
that he is in the process of etching. Rembrandt observed himself in a
mirror as he drew this etching. He then retouched the plate several
times, always making small changes, and pulled various impressions on
western and oriental paper.