Classroom in a book

Using mattes that use graphics or other clips
Four keying effects fall into the matte category. You’ll work with the Track Matte 
Key effect, because it’s the most useful and works the best. Here’s a quick rundown 
on the others:
t
Difference Matte Key
: Making this effect work smoothly is very difficult. In 
theory, you use it to place in a single set multiple actors, animals, or objects that 
could not all be in a scene at the same time ordinarily. You have to create the 
various shots with the same lighting and camera angle, and you need to work 
with high-end video to have a chance of making it work. It’s best to stick with 
green/blue screens.
t
Image Matte Key
: This matte works like the image mask used in the Gradient 
Wide transition. You apply it and open a graphic or still image, and the effect 
makes dark areas transparent and makes light areas opaque. This is a static 
effect with limited usability.
t
Remove Matte Key
: The Remove Matte effect is designed specifically for 
graphics that, when used in keyed shots, have something akin to a thin halo 
around their edges. Apply the effect to remove it.

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ADOBE PREMIERE PRO CS5 CLASSROOM IN A BOOK
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Using Track Matte Key
Track Matte Key works like Image Matte Key, but it has several advantages and 
one obvious difference. What makes it different is that you place the matte—a still 
image, graphic, or something you created in the Titler—in a video track rather than 
applying it directly to the clip.
Track Matte Key uses the clip in a separate track to define areas of transparency in 
the selected clip and reveal whatever is below it on a sequence. Its huge advantage 
is that you can animate the matte. For example, you can use Motion’s Scale param-
eter to gradually reveal the matte or move it in the clip to follow some action. The 
latter application of Track Matte Key is called a 
traveling matte
.