In looking at photographs, making them, and then writing about them, it has never seemed quite enough to say that the medium’s distinctions are purely physical; that a light-sensitive emulsion, a lens, a shutter and a continuous-tone image are the only factors that make a photograph different from a drawing or painting. For example, our reactions to a photo-realist painting, say by Chuck Close, even though it is painstakingly copied from a photograph and looks like one (even incorporating such photographic phenomena as shallow depth-of-field), is quite different from our reaction to the photograph itself. And that reaction is different not just because the photograph might be small and the painting large. It is different because of how the images were made, the acts of observation and creation they imply