2011

Softness
Colors that fall within the softness range are partially transparent. These areas
appear gray (a dark gray to light gray range) in the matte. For example, softness
makes the transition between the foreground and background of a composition
more convincing by softening what would otherwise look like an abrupt
cutout. Softness can also be used to retain transparent key-in materials or
shadows that you want to appear in the result composition.
Tolerance or Threshold
The colors that fall within the tolerance or threshold range are transparent.
These areas appear black in the matte.
Computer Generated Imagery
Images created or generated with a computer are referred to as Computer
Generated (CG) images.
Keying Workflow
The procedures and tools used to pull a key depend on the source material
you are working with, and on the complexity of the task. For example, sources
shot under ideal lighting conditions with good contrast between the key-in
and key-out content can be done very quickly. Other sources, with varying
lighting conditions, fine detail at the edges of the key, dramatic camera
movement, and other problem areas can take much longer to produce a clean
result. Make sure you understand what keying task, or keying tasks, need to
be performed so you can select the keying tools and the order of the keying
tasks that will produce the best result.
This chapter provides some keying scenarios using different keying tools to
help you understand how to use the tools. When you pull a key, you may not
necessarily need to perform all the keying scenarios in the order presented.
Moreover, there will be instances where one tool may provide you with a
clean key, and other times where a combination of keying tools will be needed
to generate the desired keying result.
512 | Chapter 22 Pulling Keys and Creating Mattes