Whereas Ingres was schooled in the old academic tradition, a tradition whose formal content was grounded in the geometric rigour of classical sculpture, Picasso's latter-day schooling was very different. This isn't just a matter of the increasingly pervasive naturalism that set in after the French Revolution. It is more specifically a matter of the influence of photography depriving the academic tradition of that formal rigour after it burst on to the scene around 1840. The old tradition's adulterated substitute retained conventions like narrative content and, as Picasso's Vollard portrait eloquently testifies, refined tonal technique in draughtsmanship. But the flesh and blood was gone.

This is abundantly evident in a drawing primer Picasso used as a student, the Cours de Dessin the French painter Charles Bargue produced in collaboration with his better-known colleague Jean-Léon Gérôme. Published as a set of 197 loose-leaf lithographs between 1868 and 1871, the Cours reappeared in book format in 2003. 

The plates in the three-part Cours include sculpture (anatomical parts and whole-figure classical masterpieces), contemporary renditions of Old Master drawings, and Bargue's own studies of male nudes from life. Apart from the life studies the Cours was mainly intended for commercial artists, and this might serve as justification for Bargue's simplistic, pseudo-classical pedagogy. But photography was a crucial factor in that pedagogy. It profoundly affected the way the world was seen by artists, including artists who considered themselves heirs to the academic tradition dating back to Louis XIV and Colbert.

By the time he was in his early teens, Picasso was copying Bargue plates including the Theseus from the Parthenon (one of the pedimental figures in the British Museum), the Belvedere Torso, and an unidentified male "Torse Antique" showing the torso's rear. In doing so Picasso internalised Bargue's treatment of the figure as the byproduct of reflected light. He won the approbation of his teachers, his artist father included, by producing tonal studies involving meticulous gradations from highlight to midtone to shadow in which the highly specific and complex shapes comprising the original sculptures — the Theseus and Belvedere Torso, at least — receive generic, simplistic treatment.

Bargue's Torse Antique, which Picasso copied very faithfully, is a particularly flagrant example of this degradation of classical form. The clearly outlined, extensively shadowed figure is reduced to a sort of diagrammatic, chiaroscuro collage — remarkably abstract and inorganic. Within a decade of making this copy, Picasso treated the dejected figures in a celebrated Blue Period work, Two Women Seated at a Bar, in a manner strikingly reminiscent of the Torse Antique plate. Here too the figures, seen from the rear, are clearly outlined while the bony structures of their backs are even more diagrammatically rendered, with a portion of the shoulder blades and the adjoining spinal channels sunk in Bargue-like shadow.