ADOBE PREMIERE PRO 2.0
User Guide
364
See also
“About keying” on page 355
Creating transparency and solid colors with mattes
About mattes
A
matte
is a still image that determines where to apply an effect to a clip. You can use matte keys to create superim-
positions, including traveling mattes. For information on using the mattes, see the topic for a specific matte key.
See also
“About alpha channels and mattes” on page 354
Using the 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.
A still image used as a matte (left) defines transparent areas in the superimposed clip (center), revealing background clip (right).
To composite clips using alpha channels or brightness values
1
Add the clip (used as a background) to a video track in the Timeline panel.
2
Add the clip you want to superimpose to any track higher than the track containing the background clip. This is
the clip revealed by the track matte.
Be sure the superimposed clip overlaps the background clip in the Timeline panel.
3
In the Effects panel, click the triangle to expand the Video Effects bin and then click the triangle to expand the
Keying bin.
4
Drag the Image Matte Key to the superimposed clip in the Timeline panel.
5
In the Timeline panel, select the superimposed clip.
6
In the Effect Controls panel, click the triangle to expand the Image Matte Key settings.
7
Click the Setup button
, browse to the image being used as the matte, and then click Open to select the image.
8
(Optional) If you’re animating the Image Matte Key over time, make sure that the current-time indicator is in the
position you want. Click the Toggle Animation icons for the settings you adjust.