5

How to Use the Keyer Filter
Getting started with the Keyer filter is easy. Here’s an example.
To create a key
1 Import a background image into your project.
This example uses a high-resolution still image of an orange sky at sunset.
2 Import a foreground image or video clip of a subject positioned in front of a green screen
or blue screen.
This example uses video footage of an actor standing in front of a green screen. Make
sure the foreground (the actor and green screen) layer is above the background layer in
the Layers list.
3 Move the playhead to a frame where the green screen is visible in the Canvas, then apply
the Keyer filter to the foreground layer.
The Keyer filter analyzes the frame and guesses the color you are trying to remove, based
on the dominant color in the image (if blue or green). For the best results, apply the filter
to the frame with the greatest amount of the color to key.
If the automatic guess is incorrect (for example, if you want to key on red), you can set
the Strength parameter in the Filters Inspector to 0 to disable automatic color sampling,
then use the Sample Color tool to draw a selection box in the Canvas around the color
you want to key. (This workflow is covered in the next task.)
The background layer shows through as long as the View control in the Filters Inspector
is set to Composite.
Note: If the clip you add a Keyer filter to is not visible in the Canvas, the initial key is pulled
based on the first or last frame in which the subject appears, whichever is closest to the
playhead.
650 Chapter 13 Keying