Chroma Keying and Working with Green Screens > Creating and Refining a Key in the Master Keyer >

# Removing Unwanted Greys

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

NotePatch parameters are animatable. Patch samples are also animatable and appear in the Channel Editor as a Matrix channel, located in the Patch folder.

There are three types of patches in the Master Keyer, that are applied to different areas of the image.

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.

To remove unwanted greys:

1. In the Master Keyer menu, select Patch1, Patch2, or Patch3 from the Sampling box.
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, Command-drag a selection box.

   When you Command-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

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

NoteTo reset Patch parameters, click the Reset button, next to the sampling box.

#### Related Information

- Creating and Refining a Key in the Master Keyer
- Chroma Keying and Working with Green Screens