Atget was a one-man archive. He made roughly 10,000 negatives from which he produced and sold an estimated 25,000 prints to individuals and institutions. He kept a reference set of all his images in his darkroom, which was located in his apartment.
Smaller, more nimble cameras transformed photographic practice during the first quarter of the 20th century, but Atget stubbornly stuck with basic, 19th-century equipment: an 18- x 24-centimeter (roughly 8- x 10-inch) view camera mounted on a wooden tripod. A view camera comprises two panels connected by a flexible, light-tight bellows. The front panel holds the lens. The rear panel is a frame that holds either a piece of ground glass (used for focusing and composing the image before exposure) or a glass-plate negative for exposure; the bellows enables the lens to be moved farther from or closer to the rear panel. Atget's camera and tripod together likely weighed 30 pounds.
After setting up his camera, which he covered with a black cloth, Atget would duck under the cloth to view the scene captured by the lens; the image would be reflected (upside down) onto the ground glass at rear of the camera. Once he had made adjustments for focus and composition, he would remove the ground glass and swap in a plate holder containing a glass negative; he evidently used clips to hold the negative in place, as they are frequently visible in his prints [see, for example, Poirier]. Atget would then take the picture by releasing the shutter, which allowed the light passing through the lens to register on the negative.
Many of Atget's architectural photographs have dark halos at the top, an effect known as vignetting [see, for example, Coin, rue du cimetière Saint-Benoît]. Vignetting was a consequence of Atget's decision to use a lens with a short focal length. The resulting wide angle of view enabled him to include the roofs of taller structures but at the expense of having the image completely cover the large glass negative. The frequency with which vignetting appears in Atget's work suggests that he found it acceptable, and perhaps even desirable—the former actor often used the halo like a proscenium arch to frame and draw attention to the subject.
Atget made contact prints using, most often, albumen silver photographic papers. He would place the negative in direct contact with light-sensitive photographic paper in a wooden printing frame, which he exposed to the sun until the image appeared. In contact printing the print is necessarily the same size as the negative (in Atget's case, 18 x 24 centimeters), although he would usually trim the print slightly.
The albumen process that Atget favored was standard for making prints in the 19th century, but it was becoming obsolete even at the start of Atget's career as more stable gelatin silver papers became available. Atget probably stayed with albumen because it enabled him to achieve great clarity, richness of detail, and nuanced tones. He occasionally made prints with matte albumen paper, which combines a starch compound such as arrowroot with light-sensitive materials, producing a velvety texture.
Atget had a complex and eccentric system for organizing his photographs that suggests the unprecedented ambition of his project. He classified his work not by date or place but by theme. He produced five major series: landscape documents, the art of Old Paris, picturesque Paris, environs, and topography (in which he documented Paris street by street, neighborhood by neighborhood). While he worked on the series for years—some over his entire career—he also assembled several more tightly focused series, including those on Parisian parks, interiors, Versailles, and the zone (an impoverished area that ringed Paris). Atget also assembled thematic albums that he sold to collectors and libraries. He would write an identifying number for the image in the emulsion of the negative; a portion of the number is often visible (in reverse) at the bottom right of his prints [see, for example, Pont Marie].
Atget often framed his subjects asymmetrically to avoid the regularity and frontality that were the standard of most architectural photographers. He was also able to capture in his photographs an almost tactile quality—so much so that the New York art dealer Julien Levy, who helped preserve Atget's work in the late 1920s and early 1930s, once confessed, "There is nothing I could ask for better than to roll myself between sheets of Atgets."
Atget's treatment of light and shadow was central to his style, especially in the expressive final phase of his career. In his early views of Paris, Atget the documentarian sought to illuminate his subject with an even clarity, the best to convey information. He usually made such images—see, for example, Environs, Amiens—in the middle of the day, when shadows were minimal. Atget's late photographs, however, are frequently marked by subjective light and deep shadows. Often made early in the morning, these pictures—such as Parc de Sceaux—use light and shadow to create a mood rather than to describe a place; they mark the apex of Atget's formal and expressive investigations of the medium.