In addition to wrestling with the wind and battling flies, field photography in the frontier had many other practical and conceptual considerations, an understanding of which brings O'Sullivan's photographs into focus. Even more than in the Civil War, field photography in the frontier was extremely demanding physically. As in the war, O'Sullivan traveled with a wagon that served as both domicile and darkroom. Sometimes, he would pack his equipment on mules or carry some of it himself, as when he climbed a two-hundred-foot basalt ridge to gain a view of a the Colorado River.²⁶ On other occasions, he carried his equipment with him up and down the steep washes along the river rapids. In King's expedition they were forced to travel by night when the snow was frozen enough that they could travel over it without falling into too often. Even at night, men and mules would disappear into thirty or forty-foot snow drifts. "In one instance not less than thirteen hours were consumed in crossing a divide, and the whole distance traveled did not exceed 2 [and a half] miles."²⁷ Traveling in Wheeler's team, O'Sullivan led a foolhardy ascent up the Colorado River. When O'Sullivan's boat, the Picture was stuck in the rapids, he made a heroic swim to the shore and dislodged it. As in the war, this kind of physical endurance bespeaks a love of adventure and a commitment to his project. Even during the exhausting trip up the Colorado, O'Sullivan would make additional forays, often scaling steep rocks and ridges, to take his photographs. Again, this evinces great patience as well as endurance and commitment.

In survey work, O'Sullivan chose a project that, like the Civil War field photography, would require a first-hand, comprehensive experience with the subject of his images. Documenting the survey was a holistic project that united photography with both physical and conceptual investigation, exploration, and discovery. Again, questions of representation and reality were at the forefront of the project, as the photographer's role ranged from documenting the geological, topographical, and aesthetic aspects of the survey for the uses of scientific description, practical map-making, and fund-raising publicity in the East. Despite the many espoused uses of survey photography, the photographer's role must have been very much in the making. In a rephotographic project Richard Dingus found and photographed the sites that O'Sullivan had photographed and discovered that O'Sullivan's photographs "were not taken with topographers or geologists in mind. The areas that they depict are not ones that would have been of cartographic value."²⁸ Clearly, the photographs had some other geologic, historical, or purely visual value to both O'Sullivan and the survey.

Isolated from the funding authorities in the East, and faced with the immediate challenges of photography and even survival on the frontier, a western frontier photographer must have been most influenced by the landscape itself, and the challenge of portraying it. This is perhaps the most difficult issue to comprehend, but fellow landscape photographers, Robert Adams and Richard Dingus provide the perspective from which to understand it.

The landscape of the West was something entirely different, much larger and more rugged, from anything O'Sullivan would have been used to in the East. Adams suggests that the experience of traveling through and photographing this landscape demanded time and patience that would have made for an acute awareness of space and time distinctly different from our modern conception of them:

The first useful thing of which the nineteenth-century photographs remind us is, I think, that space is not simple....

Among the most compelling truths in some of the early photographs is their implication of silence. Western space was mostly quiet, a fact suggested metaphorically by the pictures' visual stillness (a matter of both of their subject and composition)....

Another quality of space of which I am reminded when I look at old photographs is the easy tempo of life in it-often space looks nearly unmoving-and by extension the tempo appropriate for anyone who hopes to experience space. The pin-sharp views (how long did the photographer have to wait out the wind?), made only after establishing what amounted to a little camp in order to prepare the plates, and then taken only by substantial time exposure, suggest through the photographer's patience an appropriately respectful acknowledgement of the geologic and botanic time it took to shape the space itself. How can we hope, after all, to see a tree or rock or clear north sky if we do not adopt a little of their mode of life, a little of their time?²⁹

If travelling through and photographing the western landscape made for an acute awareness of and respectful appreciation for time and space, the two-dimensional medium of photography made for a challenge in portraying them:

At their best the photographers accepted limitations and faced space as the antitheatrical puzzle it is-a stage without a center....

The photographer's experience was, it seems to me apparent from the pictures, finally not just of the scale but of the shape of space, and their achievement was to convey this graphically.

What they found was that by adjusting with fanatical, reverential care the camera's angle of view and distance from the subject, they could compose pictures so that the apparently vacant center was revealed as part of a cohesive totality. They showed space as itself an element in an overall structure, a landscape in which everything-mud, rocks, brush, and sky-was relevant to the picture, everything part of an exactly balanced form.

Art never, of course, explains or proves meaning-the picture is only a record of the artist's witness to it. He or she can, however, be a convincing witness....It is obviously easy to assert that life is coherent, but to work out the visual metaphor for that affirmation form within the limits of an almost antlike perspective is hard and remarkable.³⁰

Adams gives us an appreciation for the challenge of depicting so large a landscape in a photograph. Similarly, Richard Dingus discovered "the distorted translations that take place whenever the three-dimensional world is represented on a flat piece of paper. The scale becomes changed and ambiguous, the space distorted. The very act of framing removes the subject from its context."³¹ Field work on the frontier challenged O'Sullivan to portray the most complex aspects of physical reality. As we will see in the next section, O'Sullivan would need to develop his compositional techniques to do so.

Clearly, O'Sullivan faced many considerations and options in his survey projects. His photographs could be geological, picturesque, sublime, imperialistic, topographical, theological, or proselytizing as he and his superiors chose. As with the Civil War project, it seems that O'Sullivan was not as limited to conventions of realism or objectivity as it might at first appear. There were many aesthetic and theoretical ideas he could have adopted and employed in his work. Yet, the absence of any such ideas as articulated and portrayed by his contemporaries is not the sign of an acquiescence to realism and objectivity, but a rejection of these ideas for the expression of an original vision. The reflections of Adams and Dingus suggest that O'Sullivan was most influenced by the physical and visual reality of the landscape itself. As we shall see, his photographs and technique corroborate this suggestion and demonstrate that as with the Civil War photographs, O'Sullivan explores and portrays the essences of his subjects through interrogative perspectives. And, again, perspective and perception are as much the subject of his work as the landscape.