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Using a hold-out matte
A hold-out matte (also known as a hold-back matte) is a duplicate of the layer you have
keyed. The hold-out matte, however, is masked to include only the area of the image
containing the key color that you want to preserve as opaque. The hold-out matte is then
placed directly on top of the keyed layer; when rendered, the hold-out matte prevents the
area from becoming transparent.
Typically, you would create a hold-out matte for only one or two frames, when the subject
is in a particular position that makes the color visible. Hold-out mattes are not recom-
mended for preserving color for longer periods of time because the effect may become
more obviously visible.
A
C
A. Original bluescreen image. The number's background is also blue. B. After keying, the number's
background is also transparent. C. Hold-out matte containing the part of the image you want to
remain opaque D. When the hold-out matte is placed on top of the keyed image, the number's
background is now opaque.
To create a hold-out matte:
1 Apply any Transform property keyframes to the original layer containing the color
screen.
2 Duplicate the layer containing the color screen.
3 In the original, apply keys and matte tools to create transparency.
4 In the copy, find the frame that contains the area you want to preserve, and then use
the Mask Tool to mask out everything in the image except the area you want to preserve.
5 Make sure that the copy (the hold-out matte) is positioned directly on top of the keyed
layer and contains exactly the same keyframes with the same values. Then render the
movie.
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