Oppenheim produces experimental films and photograms (photographs made without a camera). In the series Smoke and related works she uses the techniques of documentary photography to call the premises of the genre into question. She begins with sources such as the Imperial War Museum archive in London and the photo-sharing site Flickr, as sources for images of fire caused by natural or industrial disasters or bombing attacks (such as those over occupied France during World War II), and outputs segments of these pictures to create digital negatives. She then exposes photographic paper through the negatives, using firelight instead of the typical darkroom enlarger as a light source, then develops the photographic paper in Solarol, a specially designed developer that creates a solarized effect, reversing lights and darks. The schism between the optical expressiveness of the pictures and the scientism of the titles (which are long, descriptive, and include the date and location of the event), shows that one’s understanding of the world is partial, that photography can only represent the world, and that the documentary genre is ultimately fraught with uncertainty.