5.5

1069Motion User Guide
Additional controls
• Preserve RGB: A checkbox that, when selected, preserves smooth graphics and text.
Some images may be rendered as if they have an alpha channel, even though they
don’t. A good example is white text on a black background. Rasterized text in most
images is anti-aliased properly, and further modification to the RGB channels by the
Luma Keyer can degrade the quality of the edges. Selecting the Preserve RGB checkbox
adds transparency to the image without modifying the RGB channels, leaving smoothly
aliased text or graphics visually intact.
• Mix: A slider to set the percentage of the original image to be blended with the keyed
image. 100% is the fully keyed image, while 0% is the original, unkeyed image.
Correct or refine an existing matte
Intro to refining mattes in Motion
Keying is rarely a one-step process. Although adding a keying filter is the first step,
additional work is often necessary to create a good key that retains detail around the edge
of your subject. You can use the mask tools and alpha channel filters to turn a decent key
into a great one:
• Create a garbage mask to crop unwanted background objects in the shot that can’t be
keyed, such as the edge of a blue screen stage, lighting rigs, or tape that appears in the
background.
• Create a holdout mask to restore part of a foreground image that has been removed by
the key.
• Add a Matte Magic filter to refine matte edges.
• Add a Spill Suppression filter to manually neutralize a key color.
• Use multiple keys to isolate difficult-to-key regions in your foreground subject.
Important: When using masks with keying, apply any masks after applying the keyer filter.
Additionally, be sure to apply the masks to the same image layer that you applied the keyer
filter to.