In “Toward a Poetics of Documentary,” Michael Renov outlines four tendencies of documentary. He places these tendencies within theories of poetics in order to show that they are products of historical, cultural, and technological contexts. As a result, these tendencies serve as a way to see how to widen the gap between the image and its representation, making more room for both aesthetic and political interpretation. The four tendencies are 

• To record, reveal, or preserve
• To persuade or promote
• To analyze or interrogate
• To express

To record, reveal, or preserve

Documentary possesses a strong desire to fix a moment and to hang on to it for posterity. This fixing prevents moments from being lost, and in effect it recreates history, a reality, within a medium outside that reality. By representing that reality in an image, the gap between that image and the reality it represents seems almost to collapse, when instead it should widen. There should be no promises between an image and its representation. In other words, what we see in the image might not be what is actually there now. For example, in Roger & Me, Michael Moore shows Autoworld, which was built in Flint, Michigan, to help attract tourists. Moore’s images of the amusement park are from the 1980s. By 2006 the park had now been demolished and replaced with a parking lot and buildings for the University of Michigan-Flint. Flaherty’s Nanook of the North is an example of this tendency.

To persuade or promote

For this tendency, Renov draws directly from John Grierson. He notes how for Grierson “the screen was a pulpit, the film a hammer to be used in shaping the destiny of nations.” Often, documentaries that serve as propaganda seem to be viewed as monolothic in their intentions and voices, but persuasion can appeal in a variety of ways, including interviews, evocative images, and statistical information. The overall important thing to remember here is that the propaganda is the product of a particular moment in history and was made with specific intention. Examples of this tendency include Leni Reifenstahl’s Triumph of the Will and Frank Capra’s Why We Fight series.

To analyze or interrogate

This tendency calls attention to the seemingly direct link between image and reality. It reminds that an image is an image, and in doing so pushes open a gap in that link between the representation and the reality it represents. Within that gap the audience finds a place to analyze and even act upon what it sees. One way to raise this awareness is to call attention to the complementary relationship between sound and image. Voiceover narration, for example, typically comments on or explains the image, connecting it with other images. In Land Without Bread, the voiceover comments on the life of Las Hurdes but instead of a detached tone or an informative tone, it adopts a more cynical and judgmental one, almost disdainful of the people in the film. Another example is Surname Viet Given Name Nam.

To express

Typical representations of reality are more functional than artistic because they appear more objective. This clinging to function negates the possibility for artistic interpretation, but Renov finds that these expressions and representations should not be mutually exclusive. By allowing more expressive techniques into representation, again a space is created for exposing the gap and denaturalizing the image. Potential examples here include Joris Ivens’s Rain and The Bridge, not to mention other city symphonies. Renov stresses throughout his piece that these tendencies do overlap and that each allows room for both political and aesthetic inquiry. Source: Renov, Michael. “Toward a Poetics of Documentary.” In Theorizing Documentary, ed. Michael Renov. New York: Routledge, 1993. 12-36.