Ingres work and use of line is especially beautiful. The eye takes what it needs; but as artist I believe we can take what we want from reality and this is what he does here. The line is especially harsh and firm as it comes down her abdomen and further more as it comes down her right arm. How the line is slightly, delicately there as it draws the cushioning of her buttocks as well is a sign of ability.

Smith has a way of making minute lines work for him; not just in his shading but in the traces of the smallest lines on her face. It's effective and careful, calculating even how sharp the lines are.

Schiele has a fury of things working in his sketch; most prominently the wild curly dark lines that can be called hair. It swirls around her and is relatively uniform in thinkness and value. In the face however is where the real power can be seen. This is why I picked this particular piece of his. This sketch can show the distinction of the lines and their qualities but as one face, it still works.