Apple Motion 2 - Manual (Page 872)

872 Chapter 12 Using Shapes and Masks
Note: You may need to animate the holdout mask if the subject is moving.
4 On the newly duplicated layer, delete the original keying filters since they’re
unnecessary. If you’ve used a Spill Suppression filter, don’t delete it, since it’s probably
changing the color of the subject.
5 Feather the edge of the holdout mask you’ve just created, to make sure that it blends
in with the object you initially keyed.
6 As an optional step, you can nest the originally keyed object along with the holdout
matte you just created inside a dedicated layer so that you can manipulate the entire
subject as a single object.
Performing Multiple Keys on a Single Subject
In some instances, it may be difficult to key an entire subject with a single keying filter
while retaining fine details. For example, uneven lighting or background color might
mean that the best settings to key a subject’s hair may not work elsewhere.
If you attempt to key the entire subject with a single keying filter, chances are that you
need to use such extreme settings that a lot of edge detail is lost. In such cases, masks
can be used to isolate different parts of a subject, so that you can apply different
keying settings to each area.
To segment a subject into separate keying zones:
1 Create a new layer, and place the object you’re keying within the new layer.
2 Duplicate the object you’re keying until you have a separate duplicate for each part of
the image you want to separately key.
3 Use one of the mask tools to mask each part of the subject in each of the duplicate
objects. Make sure that all of the duplicate objects overlap, so that there are no gaps in
the foreground.
Note: You may need to animate the overlapping masks if the foreground subject is
moving.
Holdout mask combined with keyed object Holdout mask object
01112.book Page 872 Sunday, March 13, 2005 10:36 PM