Removing Unwanted Grays Using Patches

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

To remove unwanted grays using patches:

1. Set a Player view to Tool Output and, with the selection on Keyer super tool node, cycle to the alpha output—see Cycling Through Inputs and Outputs.
2. Select Patch from the Sample menu or press Shift + the number associated with the patch. For example, Shift + 1 for Patch 1.
   
3. Select Patch 1 or create a new patch from the Patch menu.
   
   Note

   You can create an arbitrary number of matte generator patches. The number of patches starts at one, and new patches can be created. Although, in theory, there is no limit to the number of patches, in practice, there are diminishing returns in terms of matte quality when adding new patches.

4. 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 Patch button is selected and the appropriate patch mode appears in the Patch box and is applied to 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.
   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 Softness slider.

5. To add more color to the patch, resample the image.
6. To use the same patch but start with a new sample, press Ctrl + Alt + drag the image.
7. To manually select a patch type, select it from the Patch box.
   Note

   If you want to reset the patch, so 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.

8. To improve the patch, use the Patch controls.

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

   Note

   To reset Patch parameters, click the Reset button under the Master Keyer UI.