In 1927, the Library of Congress (LOC) started a comprehensive project of copying manuscripts related to the history of the United States and the Americas, stored in the libraries, archives and museums of several European countries. Internally referred to as "Project A", research assistants ventured out in order to select and superintend the systematic photographing of masses of documents preserved in institutional and private collections throughout Europe. Project A was financed through a substantial grant from the Rockefeller Foundation (RF) for an initial period of seven years and resulted in over three million still images. The LOC made ample use of microphotography, a photographic technique that was not new, but subject to major improvements starting in the 1920s. These improvements concerned the camera and projector technology as well as the development of fire-resistant celluloid acetate film as a purportedly stable image carrier. Compared to manual copying and earlier forms of reproduction photography, such as Photostat duplication, the storage of visual data on light-weight and flexible 16mm, 35mm and 70mm film rolls enabled the reproduction of entire books, journals, newspapers, individual documents or bits of information.