Seamless matching. (movie JFK)

I sometimes think the media has dreamed our history up.

- Oliver Stone, Boston Globe, May 12, 1994

Though once a fresh insight, it is now a cliche to observe that in an image. obsessed world the boundaries between reality and the image have converged, that reality, as Susan Sontag put it, "has come to seem more and more like what we are shown on cameras." Yet even for Sontag, a critic with a preternatural sense for the next fashion curve, the photographic reproduction of reality still possessed an unbreakable link to the original. "The picture distorts," Sontag wrote in On Photography in 1977, "but there is always the presumption that something exists, or did exist, which is like what's in the picture."

That presumption no longer holds. Today the technology of photofabrication, in videotape and cinema as well as in the still picture, has outpaced the ability of the spectator to detect it. The telltale indicators of tampering by which a discerning eye could always perceive alterations in the photographic image - the differences in film grain, the visible lines in airbrushing, the mismatch of lighting and background - have been wiped clean by imaging technologies. In the age of seamless matching, "morphing," computer graphics, and digital-editing techniques, the integrity and veracity of any moving image, perhaps the whole notion of documentary cinema, has been called into question.

Whether as cause or consequence, a shift in philosophical outlook has abetted the technology revolution. Beginning in the late 1960s and blossoming full-blown by the mid-1970s, post-structuralism, reader-response theory, and the sundry Continental theories that came to dominate critical thought in the American university system set a relativist tone in which man (or method) became the measure of all things. In Visions of the Past: The Challenge of Film to Our Idea of the Past (1995), historian Robert A. Rosenstone expressed something of an academic consensus when he declared that "film changes the rules of the historical game, insisting on its own sort of truths, truths which arise ...