Make a color transparent with color key, About mattes, Define transparent areas with image matte key – Adobe Premiere Pro CS4 User Manual
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USING ADOBE PREMIERE PRO CS4
Compositing
Last updated 11/6/2011
Make a color transparent with Color Key
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.
When you key out a color value in a clip, that color or range of colors becomes transparent for the entire clip. Control
the range of transparent colors by adjusting the tolerance level. You can also feather the edges of the transparent area
to create a smooth transition between the transparent and opaque areas.
1
Select a clip in a Timeline panel.
2
Apply the Color Key effect to the clip.
3
In the Effect Controls panel, click the triangle to expand the Color Key effect.
4
Do one of the following to specify the key color:
•
Click the Key Color swatch to open the Adobe Color Picker, select a color, and then click OK.
•
Click the Eyedropper icon, and then click a color on the computer screen.
5
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.
6
Drag the Edge Thin slider to adjust the width of the keyed area’s border. Positive values enlarge the mask, increasing
the transparent area. Negative values shrink the mask, decreasing the transparent area.
7
Drag the Edge Feather slider to specify the softness of the edge. Higher values create a softer edge but take longer
to render.
More Help topics
About mattes
A matte is a clip (or any of its channels) that defines the transparent areas of that clip or another clip. White defines
opaque areas, and black defines transparent areas. An alpha channel is often used as a matte, but you can use a matte
other than the alpha channel. For information on using the mattes, see the topic for a specific matte key.
Define transparent areas with Image Matte Key
The Image Matte Key determines transparent areas based on a matte image’s alpha channel or brightness values. To
get the most predictable results, choose a grayscale image for your image matte, unless you want to alter colors in the
clip. Any color in the image matte removes the same level of color from the clip you are keying. For example, white
areas in the clip that correspond to red areas in the image matte appear blue-green (since white in an RGB image is
composed of 100% red, 100% blue, and 100% green); because red also becomes transparent in the clip, only blue and
green colors remain at their original values.
Note: You can use the Titler to create shapes and text to use as mattes.