Apple Final Cut Pro 7 User Manual
Page 1230
Stage 4:
Readjusting 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.
Stage 5:
Desaturating 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.
Stage 6:
Cropping Out Elements Using the Garbage Matte Filter
If there are “unkeyable elements” other than your foreground subject that you want to
eliminate from the frame, such as props, lighting fixtures, or other undesirable objects,
you can use one of the Garbage Matte filters to remove those elements. For more
information on using Garbage Matte filters, see
“Using Mattes to Add or Modify Alpha
Stage 7:
Color Correcting the Foreground and Background Clips to Match
Even if you shot your background and foreground clips to match one another, it’s unlikely
the lighting you used matches perfectly. For this reason, it’s usually necessary to color
correct either the foreground subject or the background to make sure the two match.
For more information on color correction in Final Cut Pro, see
Tip: When shooting video you intend to composite together using key filters, it’s important
to make sure that the direction of the lighting matches in both the foreground and
background shots. You can color correct for color temperature, relative brightness levels,
and contrast, but lighting direction cannot be altered.
1230
Chapter 72
Keying, Mattes, and Masks