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Keying in After Effects CS3

Article Description

Does the idea of keying conjure up images of a meteorologist on the evening news, or a shooting technique used in motion pictures? With After Effects, even the simplest, least-expensive project can take advantage of keying. The Adobe Creative Team takes us through a step-by-step example of this technique.

Removing Spill

If you look closely at the actor's hair, you'll see green highlights. This is the result of green light bouncing off the background and onto the subject. You can remove this and any unwanted green fringes around the actor with the Spill Suppressor effect. Typically, the Spill Suppressor is used to remove key color spills from the edges of a matte. It's essentially a simple desaturation filter.

  1. Select the Talent_DV layer in the Timeline panel and choose Effect > Keying > Spill Suppressor.

    You may find it easier to select the spill color if you temporarily turn off the Color Difference Key effect.

  2. At the top of the Effect Controls panel, click the effect icon next to the Color Difference Key effect to turn it off.
  3. In the Spill Suppressor area at the bottom of the Effect Controls panel, select the Color To Suppress eyedropper and click a green region near the actor's hair (see Figure 14).
  4. Turn on the Color Difference Key effect. The subject is now keyed out and the unwanted green in and around her hair is gone (see Figure 15).
  5. Hide the Spill Suppressor properties.
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