Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 446

In the Effect Controls panel, specify a key color in one of two ways:
3
• 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.
4 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.
Drag the Edge Thin slider to adjust the width of the keyed area's border. Positive values enlarge the mask,
5
increasing the transparent area. Negative values shrink the mask, decreasing the transparent area.
6 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
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.
Poorly lit greenscreen (top left) and background layer (bottom left) are combined using Color Range Key (bottom right).
See also
"Keying overview" on page 268
"Matte Choker effect" on page 448
"Simple Choker effect" on page 448
Use the Color Range effect
Select the layer you want to make transparent, and then choose Effect > Keying > Color Range.
1
Choose Lab, YUV, or RGB from the Color Space menu. If you have trouble isolating the subject using one color
2
space, try using a different one.
3 Select the Key Color eyedropper, and then click in the matte thumbnail to select the area that corresponds to a
color in the Composition panel you want to make transparent. Typically, this first color is the one that covers the
largest area of the image.
Note: To use the eyedroppers in the Layer panel, choose Color Range from the View menu in the Layer panel.
AFTER EFFECTS CS3 440
User Guide