Extract From 'The Painter and The Photograph' by Van Deren Coke

(p.5) 'Why should we want to know about a painter's use of photography? Most importantly, because the camera creates a new way of seeing and opens to an artist a repertory of pictorial imagery which is quite unlike that of direct experience. The photograph thus functions not as a crutch but as a means of expanding the painter's vision, permitting him to see aspects of a situation previously overlooked, or beyond the range of the human eye.
In the middle years of the nineteenth century..painters used photographs either as a short-cut to the imitation of nature or as a means to preserve data mechanically for future elaboration, as sketches traditionally had been used.
Regardless of intent, those who painted from photographs were subject to the special qualities of vision that characterize the camera. As these affected the painter's work, they led to new pictorial forms, which came in turn to be accepted without a clear awareness of their origins. Subsequently, as artists came to make conscious use of the differences between eyesight and camera-sight, the changes played their part in developing the idea that painting was far more than a process of recording that which meets the eye.
Through a comparison of paintings and their photographic sources, we can gain an intimate understanding of how the camera affects the artist's work. We can more intimately understand an artist's modus operandi and see how he uses the photograph: what he keeps, what he omits, what he modifies. We can see how, for purposes of clarity or expression, choices are exercised, and we become privy to the process whereby a physical inventory of fact yields to artistic sensibility. The disparities between the photograph and the painting can illuminate most directly the nature of the artist's contribution, thus shedding light on art itself.'