Adobe 12040118 - After Effects Standard Tutorial page 436

values in the thumbnail and the Composition panel are adjusted.
To produce the best possible key, make the black and white areas as different as you can so that the image retains as many shades of
gray as possible.
7. Select a matching accuracy from the Color Matching Accuracy menu. Choose Faster unless you use a screen that isn't a primary color (red,
blue, or yellow). For those screens, choose More Accurate, which increases rendering time but produces better results.
8. To further adjust transparency values, repeat steps 5 and 6 for one or both of the partial mattes. Click the Partial Matte B button or the
Partial Matte A button to select a partial matte, and then repeat the steps.
9. 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 Some keying effects have been superseded by more modern effects like Keylight.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 Keying introduction and resources.
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.
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.
5. Drag the Edge Feather slider to specify the softness of the edge. Higher values create a softer edge but take longer to render.
Color Range 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 Keying introduction and resources.
The Color Range effect creates transparency by keying out a specified range of colors in either the Lab, YUV, or RGB color space. You can use
this key on screens that consist of more than one color or on bluescreens or greenscreens that have been unevenly lit and contain different
shades of the same color.
This effect works with 8-bpc color.
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