Creating a Key by Setting the Luminance
You can create a key using only the Luminance channel. The softness and tolerance values are expressed as percentages.
This technique is useful for clips with high contrast or filmed against a black background. You can also use the Luminance channel to adjust a matte that has already been rendered. Load the matte as the key-in clip, and then adjust it in the Luminance menu.
To create a key by setting the luminance:
From the Start Mode dropdown list, select Reset to Luminance and click Confirm.
The Luminance Keyer processing pipeline is displayed in the schematic view.
Double-click the Luminance Keyer node.
The Luminance controls appear.
(a) Master Tolerance field (b) Master Softness field
Set the softness in the Master Softness field.
Set the tolerance in the Master Tolerance field.
A value of 100 for the tolerance creates an entirely opaque matte.