Color key effect, Key out a single color with the color key effect – Adobe After Effects CS4 User Manual
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USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
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Adjust transparency values for each partial matte and for the final matte by dragging one or more of the following
sliders in the Matte Controls section:
•
Black sliders adjust the transparency levels of each matte. You can adjust the same levels using the Black
eyedropper.
•
White sliders adjust the opaque levels of each matte. You can adjust the same levels using the White eyedropper.
•
Gamma sliders control how closely the transparency values follow a linear progression. At a value of 1 (the default),
the progression is linear. Other values produce nonlinear progressions for particular adjustments or visual effects.
10
When adjusting individual mattes, choose from the View menu to compare the mattes with and without
adjustments:
•
Choose Uncorrected to view a matte without adjustments.
•
Choose Corrected to view a matte with all adjustments.
11
Before closing the Effect Controls panel, select Final Output from the View menu. Final Output must be selected
for After Effects to render the transparency.
To remove traces of reflected key color from the image, apply Spill Suppressor using Better For Color Accuracy. If the
image still has a lot of color, apply the Simple Choker or Matte Choker effect.
Color Key effect
Note: Though the color keying effects built into After Effects can be useful for some purposes, you should try keying with
Keylight before attempting to use these built-in keying effects. Some keying effects have been superseded by more modern
effects like Keylight.
For information about keying in general, including links to tutorials and other resources, see “
The Color Key effect keys out all image pixels that are similar to a specified key color. This effect modifies only the
alpha channel of a layer.
This effect works with 8-bpc and 16-bpc color.
More Help topics
Keying introduction and resources
Key out a single color with the Color Key effect
1
Select the layer that you want to make partially transparent, and choose Effect > Keying > Color Key.
2
In the Effect Controls panel, specify a key color in one of two ways:
•
Click the Key Color swatch to open the Color dialog box and specify a color.
•
Click the eyedropper, and then click a color on the screen.
3
Drag the Color Tolerance slider to specify the range of color to key out. Lower values key out a smaller range of
colors near the key color. Higher values key out a wider range of color.
4
Drag the Edge Thin slider to adjust the width of the border of the keyed area. Positive values enlarge the mask,
increasing the transparent area. Negative values shrink the mask, decreasing the transparent area.