Editing – The 180-degree rule (Part 1)

The 180-degree rule is another very important film editing guideline that ensures spatial consistency on screen. By disallowing the camera to cross the action plane, the shots of a scene look consistent regardless of the way they are edited, which makes it much easier for the audience to position themselves in space. But what is that ‘180-degree’ thing? And what is an action plane anyway?

 

Establishing spatial consistency

Single subject – Whenever a character is seen to look or move to the left or to the right of the screen, there is an imaginary vertical plane — let’s call it the action plane — passing through him, which represents his line of sight or moving direction. Keeping the camera on the same side of this plane (i.e. within a 180° arc of that plane, as seen from above) ensures that the character will always be looking or moving in the same direction on screen, regardless of the camera angle. This trick — known as the 180-degree rule — establishes spatial consistency across the shots of a scene. Note: This vertical plane is often referred to as a ‘line’, simply because it looks like a line viewed from above.

180-degree rule - directional action plane

Here is an example from Terminator 2 – Judgment Day (J. Cameron, 1991). A character rides a motorbike away from the camera and to the right. This deliberate move to the right establishes a screen direction, which is maintained in the second shot. It doesn’t matter whether the camera looks forwards or backwards, as long as it stays on the same side of the action plane, the character will be facing the same screen direction and the action will look consistent throughout the shots.

In Birdy (A. Parker, 1984), we see Al exit the frame to the left, which establishes an imaginary vertical plane passing through the character (i.e. the action plane). It only feels natural that the same character is shown walking to the left again in the second shot, as the camera has remained on the same side of that plane. In Underworld (L. Wiseman, 2003), Selena — initially moving screen-right — establishes a new action plane as she turns away from the camera and to the left. In the second shot, the camera is positioned accordingly (i.e. on the same side of the plane) so that the character appears to move to the left in continuity.

Multiple subjects – The same applies to multiple characters in relation with each other (e.g. a dialog). There is an imaginary vertical plane (i.e. the action plane) passing through these characters that establishes spatial consistency on screen. If the camera is kept on the same side of that plane (i.e. within a 180° arc of that plane, as seen from above), a character initially looking to the right will always be seen looking to the right, and the other one will always be seen looking to the left accordingly, whatever the camera’s orientation.

180-degree rule - relational action plane

In Pulp Fiction (Q. Tarantino, 1994), two characters — ‘Honey Bunny’ and ‘Pumpkin’ — are talking to each other in a restaurant. The first shot establishes the action plane (i.e. passing through both characters). As long as the camera doesn’t cross that plane, ‘Honey Bunny’ will always be seen looking to the right and ‘Pumpkin’ will always be facing her to the left. It doesn’t matter who the camera is looking at, or if one character appears on one side of the screen or the other. Spatial consistency will be maintained and so will be the directions of the characters’ gazes on screen.

 

Maintaining spatial consistency

Once spatial consistency has been established, the audience get their bearings, and the action looks continuous on screen even though it is divided into dozens of unrelated shots, consecutive or not. The beauty of the 180-degree rule is that there is no ambiguity over who goes where or who faces who. In this excerpt from Young Sherlock Holmes (B. Levinson, 1985), the camera is kept on the same side of the action plane in every shot, even though the action is split over two different places. The outcome is that the action looks continuous on screen, even though many shots show completely different subjects.

In keeping with the 180-degree rule, a director has got a safety net to help maintaining continuity throughout entire scenes, if not movies. For example, Star Wars: Episode I – The Phantom Menace (G. Lucas, 1999) features a long race sequence where vehicles are always shown to move screen-right from beginning to end, even though they actually go round in circles. The following excerpt form The Lord of the Rings – The Fellowship of the Ring (P. Jackson, 2001) is a small compilation of shots occurring at different times in the film. Frodo is always shown to move screen-right from his home to Mount Doom during the entire movie — the entire trilogy indeed. Check it out.

 

What’s up?

The 180-degree rule is a powerful, tried and trusted tool to ensure spatial consistency of the action across the shots of a scene. As long as the camera stays on the same side of the action plane, the characters’ movements and gazes look consistent on screen, which alleviates the audience’s need to find their bearings and allow them to focus on the action.

In part 2, we will see that the 180-degree rule has a number of side effects that can be taken advantage of to enhance storytelling.

 

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