Chroma Keying - After Effects

In this article, we will discuss how to chroma key out a background from your video. This works with any color, but a properly lit green or blue screen will yield the best results.

1. Bring in your footage to a new composition. In the effects panel search for the effect Keylight (1.2), which is under Keying.
2. Apply this effect to your footage by clicking, holding, and dragging this effect over the footage in the composition window.
3. Now, in the Effect Controls window on the left of your screen, where it says Screen Colour, click on the little eye dropper. Then click on the footage where the color you wish to key out is the most prominent.
4. Then click on the little box that says Final Result and choose Status. You will now see what is transparent and what is opaque in your footage. Black is transparent, white is opaque, and gray is in-between. We want the subject to be white and the background to be black.
5. Twirl the triangle next to Screen Matte and increase the Clip Black until your background is solid black. Decrease the Clip White until the subject is completely white. There will be a thin gray outline around your subject (which is okay).
6. Finally, from the drop down View box, select Final Result to see your final key.

To clean up rough edges, use the Refine Matte effect. To learn more about that, go to the Refine Matte page.