Since the exposure could take as long as seven days, it was part of a process, rather than a single moment. The paper functioned as a projection surface, where each day a certain quantity of light was added to the photograph in the making. The result was a cross between a motion picture and a still photograph, although a definition is difficult, since both the location and the subject of the photograph were stationary. One thing is clear, however : whatever it was, it no longer had anything to do with the hunting movement of a photographer, while it had everything to do with the extension of a recording unit in time.