Apple MA261Z/A User Manual - Page 811

IX Step 3: Eliminate fringing with the Matte Choker filter After keying out as much of the background as you can without touching the foreground subject, apply the Matte Choker filter to eliminate any faintly remaining blue or green fringing or pixels surrounding the edge of your foreground subject. Using the Matte Choker filter to eliminate this fringing works similarly to using the Thin/Spread slider in the Chroma Keyer. You may find that, for some clips, the Matte Choker filter works better than using more aggressive settings in the Chroma Keyer, giving you a better chance of preserving as much fine detail around the edges of your foreground subject as possible. Adjust the Edge Thin slider to the right to remove faint areas of the key color around your foreground subject and to smooth out the rough edges of your key. A second Matte Choker filter can also be applied to fill holes in the foreground subject that appear as a result of aggressive settings applied to key out the background. By adjusting the Edge Thin slider to the right, you can fill in semitranslucent areas in your foreground subject, without changing the background areas you've already keyed out. For more information about the Matte Choker filter controls, see "Matte Filters" on page 682. Step 4: Readjust the Chroma Keyer filter's settings When keying, additional filters you add usually affect the overall results of previously applied filters, so after applying the Matte Choker, you'll probably want to readjust the Chroma Keyer filter's settings to take into account the effect the Matte Choker is having. Changes you make to the Chroma Keyer filter's settings affect what the Matte Choker does, so go back and forth between the Chroma Keyer and Matte Choker filters until you find a balance of settings that effectively removes the background without eating into your foreground subject. Step 5: Desaturate the key with spill suppressor filters If you have some slight color spill from the background around the edge of your foreground subject, you can use the Enhance control of the Chroma Keyer to desaturate the color spill so that it's not noticeable. If you have other regions of color spill that appear within your foreground subject- showing through a sheer dress, for instance-you may want to use the Spill Suppressor - Blue or Spill Suppressor - Green filter to selectively desaturate just the key color so that it's not noticeable. The spill suppressor filters may affect the overall color of the foreground subject, however, so you may need to use a color correction filter to compensate for this effect. Chapter 55 Keying, Mattes, and Masks 811