Classroom in a book

5
In the Effects panel, choose Video Effects > Keying, and then drag the Ultra Key 
effect to the clip in Video 2.
6
In the Effect Controls window, click the triangle next to the Ultra Key effect to 
expose its controls. Click the eyedropper icon next to the Key Color chip, and 
click the green background just over the hero’s left shoulder to choose the key 
color. Drag the current-time indicator to preview the Timeline. Most of the green 
is gone, but patches of white residue remain on the lower right and upper left.
Get an average color value 
to improve keying
The eyedropper selects a color from a single pixel. Frequently that single pixel 
does not represent the average color of the region you want to key out, leading 
to keying results that are less than satisfactory. When using the eyedropper to get 
a color sample for a key, Ctrl-click (Windows) or Command-click (Mac OS) to get a 
subsample—a 5x5-pixel area.

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282
LESSON 15 Exploring Compositing Techniques
7
In the Ultra Key Setting drop-down list, choose Aggressive. Drag though the 
Timeline again—the key is nearly perfect.
8
In the Ultra Key Output drop-down list, choose Alpha Channel to display this 
view, where the black represents the alpha channel being removed and the 
white the region that remains. You should see little black dots in the middle of 
the white, representing regions on the body that may become transparent. Let’s 
remove the dots.
9
In the Ultra Key effect, twirl the triangle next to Matte Cleanup to open those 
options. Increase the Contrast value to 40, which should remove the black dots.
10
The edge around the hero is a bit pixelated, especially at 100% zoom 
magnification. Fix that by increasing the Soften value to 40.
11
In the Ultra Key Output drop-down list, Choose Composite to return to that 
view. Drag the current-time indicator to view the finished key, which should be 
close to perfect.
If you produce a lot of videos with green- or blue-screen videos, you’ll find the 
Ultra Key effect to be a huge improvement over the Color Key and other older 
Adobe Premiere Pro effects. Even better, it’s GPU-accelerated, so if you have the 
right NVIDIA card, you can preview without rendering and quickly render your 
finished work.
#
 Note:
Adobe 
Premiere Pro Help 
contains an excellent 
description of the Ultra 
Key’s controls, so if you 
find yourself needing 
to customize your own 
keys to produce a good 
result, search for 
Ultra
in Adobe Premiere 
Pro Help.

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ADOBE PREMIERE PRO CS5 CLASSROOM IN A BOOK