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02.05 Green Screen Keylight After Effects

Keying out green screen footage in After Effects is a relatively straightforward process. This technique uses an “automatic” garbage matte with the “Simple Choker” effect to make green screen keying a bit easier even with less than perfect green screen footage.

After Effects Keylight Instructions

  1. Precompose your green screen footage into its own composition.
  2. Use the Pen Tool to select the area of the footage that you want to keep.
  3. Create a quick garbage matte around the figure using the Keylight plugin.
  4. Negatively choke the garbage matte using the Simple Choker effect.
  5. Precompose the garbage matte composition.
  6. On the garbage matte composition, add the Keylight, Key-Cleaner, and Advanced Spill Suppressor effects.
  7. Select the Combined Matte option.
  8. Clip the black and white levels of the screen matte until the unwanted areas are removed.
  9. Use the Key Cleaner effect to bring back the details in the hair.
  10. Increase the alpha contrast.
  11. Use the Advanced Spill Suppressor effect to remove the green tinge around the figure.
  12. Create a new solid layer and make it red.
  13. Drag the solid layer below the figure to check the key.


  • Use a good quality green screen. The better the green screen, the easier it will be to key out the footage.
  • Make sure the lighting is evenly distributed on the green screen. This will help to prevent any shadows or highlights from causing problems with the key.
  • Use a high shutter speed to avoid motion blur that can be harder to key out.
  • Use the Pen Tool to carefully select the area of the footage that you want to keep. The more accurate your selection, the better the key will be.
  • Experiment with the settings of the Keylight plugin until you get a good result.
  • Don’t forget to use the Key Cleaner and Advanced Spill Suppressor effects to remove any unwanted artifacts from the key.

Video Transcript:

It is very easy to key out green screen footage with After Effects. The first thing we need to do is take our green screen footage and drag it to the comp icon. This will precompose our green screen footage into its own composition.

This tutorial will show you how to use green screen footage from when you’re just starting out, where you don’t have a full studio setup and you have lots of extra background to get rid of. To get rid of the extra background we use the pen tool. Then we quickly select on the footage what we want to keep. Now, we need to make a quick garbage matte around the figure so we don’t have to key out all these areas with shadow. To do this, we type in key and we bring in one instance of the Keylight plugin. With the Keylight plugin we select a color very close to the figure. Then we go to screen matte, twirl out screen matte. And because we are not using this for the final key we can be very aggressive. Clip the black levels so there is no more black. Clip the white levels. The go back to Intermediate Result. Go back to Effects and Presets. Type in choker. Drag Simple Choker on. Negatively choke the matte. We can even type in negative 100. And this will bring out a garbage matte that follows our figure very fast. Right click in the timeline on our clip and precompose. Make sure you move all attributes into the new composition. We can call this composition Garbage Screen.

Now on Garbage Screen, go to Effects and Presets. Type in key. This time we want to drag in Keylight, Key-Cleaner and Advanced Spill Suppressor from the Animation Presets. Since we made a garbage matte around our figure we only have to deal with the pixels right here. Select the eye dropper. Click near the figure. So, that does a good job. What we want to do now is select Combined Matte. This way it combines both the mattes from different precomps. Then twirl out screen matte. We still have to get rid of this area down here. This grey section. So we will clip the black levels until that goes away. We want to use the clip black as little as possible. Here we still need to clip the whites just a little bit. We want to try to keep the clip black level and the clip white level as far apart as possible.

We can go back to Intermediate Result. And now we will use the Key Cleaner. The Key Cleaner brings back all these details in the hair. We can also bring up the alpha contrast just a bit. And then finally we need to get rid of this green tinge around the figure. That’s as simple as clicking Advanced Spill Suppressor. Now we have a very nice key. To check this, we can make a new solid layer. Make it red by clicking all the way up in the top right hand corner. Drag the solid below and that is a very nice key.

In the next video, I will show you how to integrate your video with a background.