II: Eects Compositing Essentials
Figure 6.14 What looks like a good initial Combined Matte (left) turns out to have a lot of semi-transparent pixels where you ideally want full opacity or full transparency in Status view (right).
4. Still in Status view, you have the option to try Screen
Balance at settings of 5.0, the default 50.0, and 95.0, although Keylight will preselect it based on your background color selection. This setting controls the weighting between the primary matte color (blue, green, or red) and each of the secondaries. 5. If the background is not solid black, you can boost
Screen Gain until the gray mostly disappears in Status view, although the ideal is not to raise this value at all (the next section explains how). Use this setting as sparingly as possible. 6. Optionally, set the Despill Bias using the eyedropper.
Sample an area of the foreground that has no spill and should remain looking as is (typically a bright and saturated skin tone area). I very rarely do this (see Notes).
Keylight's built-in spill suppression can and will enhance the appearance of grainess, particularly with 4:2:2 or another compressed source. The workaround (detailed ahead) is to apply the keyed layer as a track matte instead.
The rare perfect footage is now completely keyed. If it isn’t perfect (Figure 6.15), this is a decision point; how can you best divide this matte into multiple passes? Figure 6.15 Not bad for a single pass, although just between you and me, this matte has some light foreground holes that need closing. A multi-pass approach will improve even a simple matte like this.
189