Painting by Numbers presents a groundbreaking blend of art historical and social scientific methods to chart, for the first time, the sheer scale of nineteenth-century artistic production. With new quantitative evidence for more than five hundred thousand works of art, Diana Seave Greenwald provides fresh insights into the nineteenth century, and the extent to which art historians have focused on a limited—and potentially biased—sample of artwork from that time. She addresses long-standing questions about the effects of industrialization, gender, and empire on the art world, and she models more expansive approaches for studying art history in the age of the digital humanities. Examining art in France, the United States, and the United Kingdom, Greenwald features datasets created from indices and exhibition catalogs that—to date—have been used primarily as finding aids. From this body of information, she reveals the importance of access to the countryside for painters showing images of nature at the Paris Salon, the ways in which time-consuming domestic responsibilities pushed women artists in the United States to work in lower-prestige genres, and how images of empire were largely absent from the walls of London’s Royal Academy at the height of British imperial power. Ultimately, Greenwald considers how many works may have been excluded from art historical inquiry and shows how data can help reintegrate them into the history of art, even after such pieces have disappeared or faded into obscurity.