Crossing the Line
Crossing the line is an extension of screen direction and one of the most challenging shooting and editing concepts to remember. I like the idea of crossing the line metaphorically in terms of living one’s life. Visually crossing the line is becoming more acceptable and more frequently seen on screen and tube. So will I be writing more about it, but first let’s look at the rules so we know when and how to break them!
Definition
A car is traveling down a street and you shoot two angles, one from each side of the street. Perfectly valid angles but if cut together, the car appears to be going the opposite direction. Why? Because there is an invisible line in every camera set up that bisects the scene horizontally at 180 degrees.
The 180 Degree Rule: How to observe it
If two people – pawns in the diagram below – face each other, the 180 degree line runs across their heads. When editing, if you cut to the angle behind them, the person on the left now appears to jump to the right and your audience may become disoriented.
The Rule
When shooting and editing, Person A should be looking Left to Right and Person B should be looking Right to Left.
Example
Sports events are shot from one side of the field only. This way there is no chance to cut to the other side of the field and make the soccer players appear to be running toward the wrong goal.
To learn more about the rule and the line, read Chapter 1 of my book, Cut by Cut: Editing Your Film or Video.
For a superb dissection of a complex scene from Twelve Angry Men where director Sidney Lumet fastidiously observed 180 degree rule in order to avoid throwing off the audience and puncturing the drama, turn to Chapter 8, Knowing the Camera in NY writer-editor Bobbie’s Osteen’s 2009 book, The Invisible Cut: How Editors Make Movie Magic.
In the future…
…I will have more to say about crossing the line but for now, consider yourself introduced. And please report back here: How often do you notice a show crossing the line? Does it bother you? Does it have symbolic or metaphorical meaning? Why do you think the filmmaker crossed the line?
Andika Duncan, shooter-writer-preditor, Dallas, TX. 
Sandip Mahal, London, UK, working on a playout for the executives.
Sandip writes, "The person in the monitor's story is being trapped and isolated from civilisation... i can relate..." 
Susan B. Ades, Editor, NY, NY in front of her home editing suite. 
Vickie Sampson, Supervising Sound Editor, Director, Writer, Shadow Hills, CA, with dog Pinky.
Ed Abroms, Burbank, CA, on loc in Lowell, MI.
