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You may find that sampling the screen color is not enough to overcome some problems. Issues such as chattery edges, holes, or noise can sometimes be fixed using the Matte Finesse controls. These controls filter the output of the Keyer and are adjustments that are made to the matte itself, modifying the key using the frame’s content.
— Pre Filter: This slider attempts to clean up the image before colors are sampled. This adjustment can be useful when you have footage containing MPEG blocking artifacts.
— Clean Black: Clean Black is a specialized operation that eliminates noise seen as white speckling in the black area of a key. Raising Clean Black lets you “fill holes” in the background portion of a key and erode translucent edges.
— Clean White: Clean White is another specialized operation that eliminates noise (seen as black speckling when viewing a high-contrast highlight) in the white portion of a key that includes areas of the image you’re isolating and expands the key by making light parts of a key lighter the higher you raise this parameter, pushing light gray areas of the key toward white. The practical result is that raising Clean White lets you “fill holes” in the foreground portion of a key and grow translucent edges.
— Black Clip: Raising Black Clip applies a “lift” adjustment such that translucent areas of the matte (gray areas when viewing a high-contrast highlight) are pushed toward black. The range is 0 to 100, with 0 being the default setting.
— White Clip: Lowering White Clip applies a “gain” adjustment such that translucent areas of the matte (gray areas when viewing a high-contrast highlight) are pushed toward white. The range is 0 to 100, with 100 being the default setting.
— Blur Radius: In small amounts, blurring a key does well to take the edge off problem edges. However, blurring a key can also feather the edges of a key past the border of the subject you’re keying, with the result being a visible “halo” around your subject, depending on the adjustment you’re making. The range is 0 to 2000, with 0 being the default. With such a large maximum blur radius, combined with the capabilities that the In/Out Ratio provides in customizing the direction of spread, you can turn some pretty precarious mattes into surprisingly smooth and useful results.
— In/Out Ratio: Using In/Out Ratio can help eliminate fringing. Raising In/Out Ratio will fill in small black holes in the matte, while lowering In/Out Ratio below 0 will eliminate speckling by pushing small white bits of the matte toward black.
— Morph Operation: You can choose Shrink or Grow to dilate or erode the edges of the matte, or you can choose Opening or Closing to plug or expand holes to clean up a ragged matte.
— Morph Radius: Adjusts how much to shrink, grow, open, or close the key.
— Denoise: Provides a distinct way to post-process extracted keys to selectively reduce the noise in a key, getting rid of stray areas of qualification and softly filling holes in a matte.
— Shadow: Adjusts key strength based on the darker parts of the original image.
— Midtone: Adjusts key strength based on the midtones of the original image.
— Highlight: Adjusts key strength based on the brighter parts of the original image.
— Post Filter: Performs a final clean-up of the key, using the original image for reference; useful for bringing back some fine detail in sharp edges or hair.