Using the Luma Keyer Filter
The Luma Keyer filter pulls a key from an image or clip based on a selected range of image
lightness. Although typically used to key out a white background behind a foreground
subject, the Luma Keyer filter can also be used to generate creative effects by turning a
narrow range of image brightness transparent. The Luma Keyer filter can also isolate
rasterized logo and text graphics from a black or white background.
Luma keys are most effective when you’re keying a subject with a range of lightness
different from the area you’re turning transparent. For example, if you’re keying a black
background, the foreground subject should not have have deep shadows or dark areas
that might get keyed with the background. Generally speaking, shadows and highlights
in the image usually make this a difficult filter for pulling a perfect key.