Composite
Description
Composites a foreground over a background using a matte. Either two or three inputs can be used.
• Two inputs: Foreground RGBA and Background
• Three inputs: Foreground, Background, Matte
Note: You can change Composite’s input order with the User Interface > Trees > Input Order preference. By default, FG, BG is selected, but you can change it to BG, FG if you’d like.
Silhouette is a straight, unmatted compositor and its composite nodes expect unpremultiplied images. In addition, it is best practice to unpremultiply before color correcting premultiplied images so as to avoid unexpected results. If you are working with premultiplied images, you have the following options:
• In the Source parameters, identify the alpha as Premultiplied. This will unpremultiply it.
• Unpremultiply the image within the Composite node.
• Use a Composite > Unpremultiply node before the premultiplied image hits the Composite node.
Node Group
Composite.
Controls
Amount
Sets the amount of the foreground.
Matte Input
Chooses which channel from the Matte input to use in the composite.
Red
The red channel is used for the matte in the composite.
Green
The green channel is used for the matte in the composite.
Blue
The blue channel is used for the matte in the composite.
Alpha
The alpha channel is used for the matte in the composite.
Luminance
The average luminance of the RGB channels is used for the matte in the composite.
Unpremulitply
Divides the RGB channels by the alpha channel.