Sometimes it’s hard to key out a background without messing up the colors of the foreground subject that you’re trying to isolate. Rather than trying to get everything keyed out and looking good on a single layer, try this: Duplicate the layer (Command-D [PC: Ctrl-D]), apply the keying effect to the top layer, and use the top layer as a track matte for the underlying layer. (Note: To apply a track matte, click the Toggle Switches/Modes button at the very bottom of the Timeline until you see the TrkMat column, and then select one of the transparency options from the drop-down menu.) You can use the Levels effect (Effect>Color Correction>Levels) to exaggerate color differences in the top layer before applying the keying effect.

written by Michael Coleman
“These tips originally appeared in the March/April 2009 issue of Layers: The How-To Magazine for Everything Adobe.”

Tags: Adobe after effects, background, colors, effect, foreground, isolate, key, key out, matte, single layer, track, transparency