Photographing the sky posed a special challenge to early photographers because photographic emulsions were not equally sensitive to all colors of the spectrum. Most photographers calculated the exposure for the landscape, which often left the sky overexposed, producing areas of low density on the negative that appeared gray or mottled on the print. Clouds were especially difficult to capture. To overcome this defect, many photographers painted out the sky on the negative, which resulted in a bright, blank sky on the print. Occasionally, they enlivened these blank skies by painting clouds on the negative. Other photographers made two negatives—one exposed for landscape and another, faster exposure for the sky—that were printed as a single image.
In the mid-1850s Marville undertook a series of experiments to photograph the sky, resulting in some of the earliest successful sky and cloud studies. In certain photographs, Parisian landmarks—the dome of the Church of the Invalides, for example—anchor the composition and orient the viewer, while in others Marville abandoned any reference to the city, filling the entire frame with wispy and streaky formations that verge on pure abstraction. In 1857, he exhibited several sky studies—including one printed on silk—to copious praise at the French Society for Photography.