How does Frank Auerbach achieve a sense of three-dimensional depth in his drawing? If Auerbach's purpose is to capture something of the sitter's personality, what does his drawing suggest about his subject's (sitter's) temperament?

photography had emerged as an elite art pursued by a few creative individuals for a few wealthy patrons. but now, said bauldelaire, it was succumbing to "the great industrial madness of our times." it was becoming a mass production industry that catered to middle-class tastes, including a taste for gadgetry. the stereoscope, the first 3d imaging system, had turned looking at photographs into parlor entertainment. a "thousand hungry eyes were bending over the peepholes of the stereoscope as though they were the attic-windows of the infinite.