The Luma Keyer computes the luminance of the image and removes pixels based on a threshold value, affecting the alpha channel. The softness value can be added to set some fall-off for the key. When the softness is 0, only the pixels that fall within the tolerance range are keyed out. The luminance keyer can either output a matte or a pixel selection.
The Luma Keyer UI has four controls.
| Use: | To: |
|---|---|
| Channel | Select the luma or the color channel luminance that will be used to pull a key. |
| Key | Set the range of pixels to key based on the threshold range. |
| Threshold | Set the range of the pixels to key. Increasing the threshold removes less prevalent pixels from the composition. |
| Softness | Soften the edge of the key. |
