Hine's photographs were important in the battle to change the child labour laws. The National Child Labour Committee wrote to him: "The work you did... for [us] was more responsible than any or all other efforts to bring the facts and conditions of child employment to public attention." He photographed under difficult conditions with heavy and awkward equipment, often encountering opposition from mill owners. Primarily concerned with working conditions, Hine was also interested in the theme of modern society's ambivalent relationship with industrialization and machinery - a theme that occurs in other art of the 1920s and 30s.