Like many editing tricks, you've probably seen J-cuts and L-cuts before without actually realizing that you were seeing a J-cut or an L-cut.
In a J-cut, the sound of the next scene precedes the picture, and in an L-cut, the picture changes but the audio continues.
Imagine you have a scene of dialogue between Person A and Person B where the clips cut back and forth every time each person speaks. In other words, you have a clip of Person A talking, then you cut to a clip of Person B talking, then you cut back to Person A when they begin talking again, and so on and so forth. This is referred to as a "ping-pong" editing, which can be disorienting and kind of stylistically boring.
By using a J-cut, you could stay focused on Person A's face when Person B begins talking.
Conversely, you might want to focus on Person B's face before Person A is finished speaking. In this case you would use an L-cut.
In either scenario you allow yourself the opportunity to show the reaction of the person who is not speaking, which is a powerful tool provided by your actors that you should take advantage of.
Like any tactic or technique, J-cuts and L-cuts shouldn’t be overused as they would then lose their impact.
Image: an example of an L-cut
Think about the films we watch and the dialogue sequences within them. During these sequences, the editor isn’t constantly cutting back and forth to each character as they talk. Doing this would be very distracting. Instead, an L-cut is used.
This technique sees Character A speaking, but then the scene cuts to Character B as Character A continues their dialogue. By doing this, the editor is allowing viewers to hear the dialogue while also seeing the reaction of Character B, giving the audience a better overall understanding of the scene.
Image: an example of a J-cut
The J-cut is the opposite of the L-cut. With this technique, the viewer hears the dialogue of Character A — but only sees Character B on screen.
From this shot of Character B (which provides emotional information and context for the scene), the editor cuts back to Character A.
Another use of J & L cuts are ones that include B-Roll (footage with no spoken word which gives context to the edit) like the example below.
Using J & L cuts this way is an effective way of giving the b-roll context in a time efficient manner because we still hear the content of the interview being played underneath.
It's also a good way of transitioning between two speakers in a documentary style interview.
The L-cut and J-cut in this sequence make the transition between speakers feel natural, as opposed to a jarring jump cut from Speaker A to Speaker B.
Insert your videos into premiere and trim and place them as needed.
You can either unlink your audio and videos (Right-Click - Unlink) and use the Rolling Edit tool or you can just hold down ALT and use the rolling edit tool.
The Rolling Edit tool will trim just the audio or just the video.