You can use the Degrain node to remove grain from any clip in the pipeline. For example, degrain the KeyIn clip by using a Degrain node at the beginning of the Matte branch to make it easier to extract the matte. Similarly, add the Regrain node to the pipeline to add grain to an image. Keep in mind the following when working with Degrain and Regrain nodes:
The Degrain and Regrain menus in the Modular Keyer contain the same set of controls as the Degrain and Regrain menus accessed from the A/V Tools menu on the EditDesk (only the menu layout is slightly different). See Adding and Removing Film Grain.