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:

1. In the Keyer, click Keyer, and then click Luminance.

   The Luminance controls appear.

   
   

   (a) Master Tolerance field  (b) Master Softness field  

2. Set the softness in the Master Softness field.
3. Set the tolerance in the Master Tolerance field.

   A value of 100 for the tolerance creates an entirely opaque matte.

   NoteYou can reset values in Master Softness and Tolerance fields by clicking the Reset button.

For floating-point images, you can use a node in Batch or the Modular Keyer to create a 16-bit key. See Keyer-Luma Node.