You are probably wondering why this woman is about to spread her legs. Is she?
The image is strange enough. A large table. To the left, lying on the table, a woman, nude except for a cloth which covers her right shoulder and arm and her loins. To the right, a man with a moustache, peering at the woman through a wooden frame covered with a rectangular grid of threads. In his hand a pen, resting on a blank piece of paper, blank except for the same rectangular grid as in the wooden frame. We, the specator, are standing, looking down at the table and the two protagonists.
Under her head are two pillows, her eyes are closed, her full breasts are nude. Her left arm seems to be moving. Is it covering her genitalia? Or possibly removing the cloth from her groin so that he can start drawing her most intimate parts? Why is she folding her legs and lying so close to the wooden frame? Will she open them in a minute?
The man looks very serious. He concentrates. He seems unaware that there is eroticism in her gesture.
It’s a mystery why the German artist Albrecht Durer included her in his otherwise dead serious Painter’s Manual. In any case, she is not present in the first edition. I’ve managed to track her down in the edition of 1538.
The print is commonly known as Artist and Model in the Studio but more exactly called Der Netzzeichner, the net draughtsman. The net refers to the wooden frame, commonly referred to as an Albertian grid, a mechanical aid to draw perspective, sometimes called a perspectograph.
The image of this model and her draughtsman is one of my favourite pieces of Renaissance erotica. Not only is it a commentary on the invention of the graphical perspective, essential to the development of the Renaissance visual arts, but secondly, it is a most perverse work in the sense that the lack of contact — both people being separated by a mechanical device — illustrates the development from one-to-one erotica to the mechanical diffusion of mass-produced pornography.
The version shown above  is the largest digital version I could find.