Why is it that no photograph of a person has the depth a painted portrait can have? The two embody different quantities of time. A photograph is a "snapshot," whether or not it was posed; it shows one particular moment of time and what the person looked like right then, what his surface showed. During the extended hours a painting is sat for, though, its subject shows a range of traits, emotions, and thoughts, all revealed in differing lights. Combining different glimpses of the person, choosing an aspect here, a tightening of muscle there, a glint of light, a deepening of line, the painter interweaves these different portions of surface, never before simultaneously exhibited, to produce a fuller portrait and a deeper one. The portraitist can select one tiny aspect of everything shown at a moment to incorporate into the final painting.