A single line. Not a break, not a crossing, not a second supporting stroke.
That is how Claude Mellan, a 17th-century French engraver, created one of the most astonishing faces in European art. In “The Sudarium of Saint Veronica”, he began engraving at the tip of the nose and unwound a continuous spiral across the entire surface, without lifting the burin even once. The secret lay in the pressure: he pressed harder where he needed shadow and lightened the stroke where he wanted light, until the line alone generated volume, depth, and expression.
Mellan lived between 1598 and 1688, and this piece is still studied today as a technical feat almost impossible to reproduce by hand. No cross-hatching, no stippling: just absolute control of one hand over a single endless curve.