In light of how his contemporaries envisioned the landscape, O'Sullivan's photographs appear original in their apparent simplicity and objectivity. Studies of O'Sullivan's photographs have revealed that he used an impressionist technique. This technique,too, reflects a rejection of preconceived perceptions and perspectives in favor of an empirical exploration and honest expression of the subject. Yet, for all its deference to the subject, O'Sullivan's technique also reflects the feeling which his photographs evoke in its embrace of subjectivity.
In the Civil War images, O'Sullivan used perspective and composition to maximize meaning through symbolic associations, the transference of visual power into the appearance of intrinsic significance and the transference of subtle artistry into the legitimacy of apparent objectivity and truth. Richard Dingus's work in the Rephotographic Survey Project, revisiting and photographing the frontier scenes that O'Sullivan captured, revealed that he often canted, or tilted, his camera quite intentionally in order to emphasize certain attributes of the landscape. This corroborates the idea that O'Sullivan's technique was essentially one of manipulating perspective and composition. He writes:
Bridal Veil Falls near Provo, Utah, was the first site I visited that showed O'Sullivan's unquestionable canting of the horizon. The matched view...dramatically isolated an immense rock face where faulting was evidenced by the curving, bent, and twisted strata...
When I first located O'Sullivan's position and set up my camera I thought something was wrong. I was using a 90mm wide-angle lens on a 4x5 camera and knew that my lens would probably provide just enough coverage to match O'Sullivan's. But when I looked on my ground glass I saw that my framing wasn't the same. Only when I tilted my camera so that the right side was higher than the left could I duplicate O'Sullivan's photograph. The substantial degree of his tilt can be estimated by looking at his waterfall and realizing that it is not cascading to one side, as it might seem, but plummeting vertically over the edge of an abrupt cliff...
That this tilt was intentional was corroborated when I found another photograph that O'Sullivan had taken from the same vantage point and at about the same time...For the second view he had simply shifted his camera to the left, without moving his tripod, and centered his framing on the waterfall. He corrected the angle in this view so that the waterfall is seen to drop straight down....
It seems clear that O'Sullivan oriented his frame to isolate the rock face's different attributes. The tilted view emphasized the drama of geologic forces. Although the frame was not level with the actual horizon, the composition within the frame was balanced formally by its nearly symmetrical repetition of shapes.1
O'Sullivan's canting of his frame is much like posing the body of the "rebel sharpshooter" at Gettysburg. It may not accurately convey the factual reality of the landscape, but it does convey the dramatic, visual, and geological reality of it. As in his first project, he uses formal compositional devices to portray the impression his subject evokes. Dingus also points out that a diary entry of geologist, Grove Karl Gilbert, who worked with O'Sullivan in Wheeler's expedition, notes O'Sullivan's "use of the camera to portray the way a place seemed rather than how it actually was:"
"O'Sullivan took photos at Camp Keg and again further up at a point where a side canyon gives the impression that the main canyon is narrower than it is...Here we found a large pool of water that we made use of for reflections. Took a glass picture."2
Even O'Sullivan's own words as quoted in Harper's Monthly Magazine, demonstrate his sensitivity to the impressions created appearances:
There is in the entire region of the falls such wildness of beauty that a feeling pervades the mind almost unconsciously that you are, if not the first white man who has ever trod that trail, certainly one of the very few who have ventured so far.3
O'Sullivan was one of the first white men to venture where he did. Yet, that is not what he says. He says that the beauty of the place makes him feel as though he were one of the first white men to discover it. Note his attention to the almost unconscious way in which this impression is created. The remark is too self-conscious and echoes critics' observations of his own work too perfectly to deny that he mimicked and drew upon this evocative property of nature.
Finally, Dingus also shows that O'Sullivan made multiple photographs of several scenes from different perspectives, each emphasizing different aspects of the scene. In one of his pictures of "Witches Rocks," O'Sullivan went so far as to mask out the sky to emphasize the monumentality of one of the rock structures. Another image from the series emphasizes the precarious positions of these structures by canting the picture to create the tension of opposing diagonal lines and the illusion that the structures sit on ground more inclined than it actually is .4
Dingus's discoveries are undeniable evidence of the calculation O'Sullivan put into his photographs, and corroborates that he was the artist the power of his photographs suggests he was.