WHAT it is…
A rule in continuity editing which dictates that a cut between two shots which inverts the spatial relationship between characters or objects should never be made. That is, if two characters occupy the left and right sides of the screen in one shot, a cut should not be made where they swap their positions because it disorients the audience and breaks their attention.
WHY
it is special...
Since, during the course of a scene, the viewer is acclimated to - among other things like costume and lighting - the spatial configuration of the scene, sticking to the 180 Degree Rule helps achieve a smooth transition between shots. This helps the audience to take the entire setup for granted and thus provides a better illusion of being present in the scene.
WHEN
it is deployed...
The 180 Degree Rule is one of the most religiously adhered-to rules of narrative film editing. Most television serials and commercial cinema are still edited with a keen consciousness of the rule. However, in the case of action scenes where handheld and moving cameras are the norm, the necessity for sticking to this rule is circumvented because the need for a cut itself is eliminated.
WHERE
to find it...
At a pivotal moment in Pedro Almodóvar's Tie Me Up! Tie Me Down! (1990), the director violates the 180 Degree Rule by cutting between two camera setups that are located on either side of the plane of interest, without re-establishing the scene. The transition is utterly disorienting and it presages the character switch – between captive and captor – that radically reconfigures the core idea of the film.
How it is used…
Conversations
The 180 Degree Rule finds its greatest use in scenes of conversation between two characters. Most conversations are edited in Shot-Reverse Shot format and are shot over the shoulder of the actors wherein we see the face of the speaker and the back of the listener in tandem. Here the camera nears the 180-degree line as much as possible from both directions, but never more than that.
Transgression
Certain unconventional filmmakers have transgressed this deeply embedded tenet of industrial filmmaking either as a means to distance the audience from the proceedings – hence prompting them to reflect on the happenings – or to make a conceptual point by the transgression. But such a disturbing transition could be ‘neutralised' by inserting an establishing shot of the scene in between.
