X

598Final Cut Pro User Guide
3. Click Matte Tools to reveal the following controls:
• Levels: Use this grayscale gradient to alter the contrast of the keyed matte, by
dragging three handles that set the black point, white point, and bias (distribution
of gray values between the black point and white point). Adjusting the contrast of a
matte can be useful for manipulating translucent areas of the key to make them more
solid (by lowering the white point) or more translucent (by raising the black point).
Dragging the Bias handle right erodes translucent regions of the key, and dragging
the Bias handle left makes translucent regions of the key more solid.
• Black, White, Bias: Click the Levels disclosure triangle to reveal sliders for the Black,
White, and Bias parameters. These sliders, which mirror the settings of the Levels
handles described above, allow you to keyframe the three Levels parameters (using
the Add Keyframe button to the right of each slider). Keyframing the Black, White,
and Bias parameters may yield a better key, one that adapts to changing blue-screen
or green-screen conditions.
• Shrink/Expand: Use this slider to manipulate the contrast of the matte to affect
matte translucence and matte size simultaneously. Drag the slider left to make
translucent regions more translucent while simultaneously shrinking the matte.
Drag the slider right to make translucent regions more solid while simultaneously
expanding the matte.
• Soften: Use this slider to blur the keyed matte, feathering the edges by a uniform
amount.
• Erode: Drag this slider right to gradually increase transparency from the edge of the
solid portion of the key inward.