With Robert J. Flaherty's Nanook of the North in 1922, documentary film embraced romanticism; Flaherty went on to film a number of heavily staged romantic films, usually showing how his subjects would have lived 100 years earlier and not how they lived right then (for instance, in Nanook of the North Flaherty does not allow his subjects to shoot a walrus with a nearby shotgun, but has them use a harpoon instead, putting themselves in considerable danger).
Some of Flaherty's staging, such as building a roofless igloo for interior shots, was done to accommodate the filming technology of the time. In later years, attempts to steer the action in this way, without informing the audience, have come to be considered both unethical and contradictory to the nature of documentary film. On the other hand, both the story line and content of any documentary are imposed by the filmmaker.
In a notorious instance, for the documentary White Wilderness in 1958, Disney technicians built a snow-covered turntable to create the impression of madly leaping migrating lemmings and then herded the lemmings over a cliff into the sea. This fakery distorts the popular understanding of lemmings to this day. While lemmings do swarm in some years, they do not commit mass suicide.
The newsreel tradition is an important tradition in documentary film; newsreels were also sometimes staged but were usually reenactments of events that had already happened, not attempts to steer events as they were in the process of happening. For instance, much of the battle footage from the early 20th century was staged -- the cameramen would usually arrive on site after a major battle and reenact scenes to film them. Dziga Vertov was involved with the Russian Kino-Pravda newsreel series ("Kino-Pravda" means literally, "film-truth," a term that was later translated literally into the French cinema verite). Frank Capra's Why We Fight series was a newsreel series in the United States, commissioned by the government to convince the U.S. public that it was time to go to war.
The continental, or realist, tradition focused on man within man-made environments, and included the so-called "city symphony" films such as Berlin, Symphony of a City, Rien Que Les Heurs, and Man with the Movie Camera. These films tended to feature people as products of their environment, and leaned towards the impersonal or avant-garde.
The propagandist tradition consisted of films made with the explicit purpose of persuading an audience of a point. One of the most notorious propaganda films is Triumph of the Will. Frank Capra's Why We Fight newsreel series was explicitly contracted as a propaganda series, in response to Leni Riefenstahl's film Triumph of the Will; the series covered different aspects of World War II and had the daunting task of persuading the United States public to go to war. The series has been selected for preservation in the United States' National Film Registry.
In the 1930s, documentarian and film critic John Grierson argued in his essay First Principles of Documentary that Robert Flaherty's film Moana had "documentary value," and put forward a number of principles of documentary. These principles were that cinema's potential for observing life could be exploited in a new art form; that the "original" actor and "original" scene are better guides than their fiction counterparts to interpreting the modern world; and that materials "thus taken from the raw" can be more real than the acted article. In this regard, Grierson's views align with Dziga Vertov's contempt for dramatic fiction as "bourgeois excess," though with considerably more subtlety. Grierson's definition of documentary as "creative treatment of actuality" has gained some acceptance, though it presents philosophical questions about documentaries containing stagings and reenactments.
In his essays, Vertov argued for presenting "life as it is" (that is, life filmed surreptitiously) and "life caught unawares" (life provoked or surprised by the camera). Cinema verite borrows from both Italian neorealism's penchant for shooting non-actors on location, and the French New Wave's use of largely unscripted action and improvised dialogue; the filmmakers took advantage of advances in technology allowing smaller, handheld cameras and synchronized sound to film events on location as they unfold. The films Harlan County, U.S.A (directed by Barbara Kopple), Don't Look Back (D. A. Pennebaker), Lonely Boy (Wolf Koenig and Roman Kroitor) and Chronicle of a Summer (Jean Rouch) are all considered cinema verite. The genre has different names in different countries; "cinema verite" is perhaps the most common now, but in the United Kingdom the same movement was called "free cinema" and in the United States, "direct cinema." The directors of the movement also take different viewpoints on their degree of involvement, Kopple and Pennebaker, for instance, choosing non-involvement, and Rouch, Koenig, and Kroitor favoring direct involvement or even provocation when they deem it necessary.
Another recent development in the field of documentary is the creation of compilation films: for instance, The Atomic Cafe is made entirely out of found footage which various agencies of the U.S. government made about the safety of nuclear radiation (e.g., telling troops at one point that it's safe to be irradiated as long as they keep their eyes and mouths shut). Meanwhile The Last Cigarette combines the testimony of various tobacco company executives before the U.S. Congress with archival propaganda extolling the virtues of smoking.
Modern documentaries have a substantial overlap with other forms of television, with the development of so-called reality television that occasionally verges on the documentary but more often veers to the fictional.1927-1950s