How to Use Chroma-Key on Adobe After Effects

Adobe After Effects a has plug-in called the Keylight which has made Chroma-keying footage shot on a green or blue screen a very quick and simple process. Assuming you already have a basic understanding of After Effects and Compositing, here is a step by step on how to use the Keylight plug-in.

  1. Import your footage into After Effects and set up a project.
  2. Step 2

    With your clip containing the footage to be keyed selected, go to the Effects Menu and choose Keying and then Keylight.

  3. Step 3

    In the Keylight Effects control menu, select the eyedropper tool next to “Screen Color” and click on the green or blue color of the screen that you want to remove from your footage.

  4. Step 4

    While still in the Keylight Effects control menu, and under “About,” look for “View.” From the pull down menu next to “View” choose the “Screen Matte” option. You are now viewing the footage in two-tone black and white only. Here your goal is to make the color you want to key out completely black, and the rest of your footage completely white.

  5. Step 5

    While still in the Keylight Effects control menu, and under “About,” expand the “Screen Matte” options. Adjust “Clip Black” number from 0 up until all the white is removed from your key area, making it completely black. This will generally be no more than approximately 30.

  6. Step 6

    Adjust “Clip White” number from 100 down until all the black is removed from your foreground footage (the footage in front of the keyed background) and it is completely white. This will generally not be less than approximately 70.

  7. Step 7

    Under the “Screen Matte” options, look for “Screen Shrink/Grow.” Make that number negative 0.5.

  8. Step 8

    While still in the Keylight Effects control menu, but back under “About,” look for “Screen Pre-blur. Adjust that number to approximately 2.5.

  9. Step 9

    Go back to the Main Effect Menu, and choose “Matte”, then “Simple Choker.” In the Simple Choker effects control, look for “Choke Matte.” Make that number between 0.75 and 1.5, depending on the edge of your footage. The “Simple Choker Effect” helps remove some of the edge around your foreground footage.

  10. Step 10

    Finally, go back to the Keylight Effects control, and under “About,” go back to “View.” From the pull down menu next to “View” choose the “Final Result” option. Now your background is transparent and you are ready to composite your footage.