If you have unwanted grey areas in the matte, you can use up to three patches to isolate a range of colours to be included in, or excluded from, the key.

To remove unwanted greys:

1. In the Master Keyer menu, select Patch1, Patch2, or Patch3 from the Sampling box (or press 1, 2, or 3).

   
   

2. Set the view to Matte view or Result view.

   
   

3. Sample the image where you want to apply the patch. To sample a single pixel, click the image. To sample an area of the image, Ctrl-drag a selection box.

   When you Ctrl-drag to sample, the sample is outlined in red. In the Master Keyer menu, the Patch button is enabled and the appropriate patch appears in the Patch box and is applied to the image.

   NoteA Patch button is either enabled or disabled for the entire clip—you cannot turn it on and off for different frames in the clip.

   
   

   (a) Patch buttons  (b) Patch controls  (c) Patch boxes  

   Selected patch:	Is applied to:
   Black	Areas of the image to be included in the black part of the matte.
   White	Areas of the image to be included in the white part of the matte.
   Edge Analysis	Areas of the image that are along the edge of the key. Edge Analysis is useful when there is a specific edge you want to erode but cannot do so with the Matte parameters. You can then increase or decrease the softness of this patch using the Soft field.

4. To add more colour to the patch, resample the image.
5. To use the same patch but start with a new sample, Ctrl+Alt-drag the image.

   The sample is outlined in green, indicating that you are resampling the current patch.

6. To manually select a patch type, select it from the Patch box.
   NoteIf you want to reset the patch so that you can automatically select the patch type, you must disable the patch and set the patch type to Off. You can then resample an area in the image and generate a patch type.
7. To improve the patch, use the Patch controls.

   Drag:	To:
   Range	Increase or decrease the colour range that is included in the patch.
   Soft	Soften the edge.