*Keying
with Premiere's Chroma or Luma Key Filter
Follow
these steps to key out the green color using the default Chroma Key
filter:
-
To start the process of
keying out the green background, select Window > Effects to open
the Effects panel. As you can see, there are a lot of effects
that come with Premiere.
2.
Navigate to Video
Effects > Keying > Chroma Key in the Effects panel (see Figure 8).
Drag the Chroma Key plug-in from the Effects panel to the thumbnail
in the Video 1 channel.
Figure 8.
Choosing the Chroma Key plug-in for keying video
3.
To adjust the Chroma Key
plug-in settings, select Window > Effect Controls. Changes you make
are reflected in the image in the Monitor window. The Effect
Controls dialog box contains three settings that you can adjust (see
Figure 9):
-
Color:
You can choose which color to remove by selecting it from
the Color Picker or using the eyedropper to sample the color
for removal.
-
Similarity:
Similar to the Magic Wand tool in Fireworks 8 or Photoshop
CS2, the Similarity value determines how wide a range of the
selected color to remove.
-
Blend:
This control blends the edges of the mask to smooth things
out. If you're thinking of this effect as feathering on the
edges of the mask, you are on the right track. In the case
of Premiere, you are blending the edges of the mask with an
underlying image placed under the video. Although this is
not necessary in this instance—because there is nothing
behind the talking head—it is a good habit to develop.
o
Smoothing:
This is the amount of anti-aliasing that is applied to the edge of
the mask: None makes the edge look ragged, Low applies a subtle
blend, and High (shown here) applies enough to ensure a smooth edge
and any content placed behind the video.
Figure 9.
Adjusting the Chroma Key plug-in settings to control the masked area
-
Drag the Eyedropper tool
in the Color setting onto the green area of the clip in the
Monitor window. As you drag the eyedropper, some of the green
area turns black. This indicates the color to be masked. Release
the mouse to sample the color.
-
Drag the Similarity
slider to the right. As the green disappears, the background
turns black behind the talking head. Pay particular attention to
the hair and shoulders of the talking head. Try to remove as
much green as possible. I found that a value of 54 turned out to
be just about right.
-
Drag the Blend slider to
a value of about 16. This slider adds some feathering to smooth
the edge.
7. To preview your efforts
so far, click the Mask Only button at the bottom of the Effect
Controls dialog box. This turns on the mask. What you are looking
for is a solid black background and a solid white talking head (see
Figure 10).
Tip:
You don't have to use the sliders to make these adjustments. You can
also click the values—the blue numbers—in the percentage area and
drag to change them. This is a neat trick but I would suggest using
the sliders until you are more comfortable with the interface. You
can also double-click the values and enter them manually.
Play around with these
values until the apperance looks best to you.
Figure 10.
By selecting Mask Only in the Effect Controls, you get a good look
at the mask you are creating
Keying with the Color Key
Filter
Follow
these steps to key out the green color using the extra Color Key
filter provided with the Adobe Video Collection:
-
To start the process of
keying out the green background, select Window > Effects to open
the Effects panel. As you can see, there are a lot of effects
that come with Premiere.
2. Navigate to Video
Effects > Keying > Color Key in the Effects panel (see Figure 11).
Drag the Color Key plug-in from the Effects panel to the thumbnail
in the Video 1 channel.
Figure 11.
Choosing the Color Key plug-in for keying video
3.
To adjust the Color Key
plug-in settings, select Window > Effect Controls. Changes you make
are reflected in the image in the Monitor window. The Effect
Controls dialog box contains four settings that you can adjust (see
Figure 12):
-
Key Color:
You can choose which color to remove by selecting it from
the Color Picker or using the eyedropper to sample the color
for removal.
-
Color Tolerance:
Similar to the Magic Wand tool in Fireworks 8 or Photoshop
CS2, the Color Tolerance value determines how wide a range
of the selected color to remove.
-
Edge Thin:
This control expands or contacts the mask.
o
Edge Feather:
This does exactly what it says. The transition between the edge of
the mask and the subject can be rather abrupt sometimes. This
control adds a small amount of feathering to the edges of the mask
to smooth things out.
Figure 12.
Adjusting the Color Key plug-in settings to control the masked area
-
Drag the Eyedropper tool
in the Key Color setting onto the green area of the clip in the
Monitor window. As you drag the eyedropper, some of the green
area turns black. This indicates the color to be masked. Release
the mouse to sample the color.
-
Drag the Color Tolerance
slider to the right. As you drag the slider, the black area
expands. Pay particular attention to the hair and shoulders of
the talking head. Try to remove as much green as possible. I
found that a value of 91 turned out to be just about right.
6.
Drag the Edge Feather
slider to a value of about 1.6 or 1.8. When you remove the green,
you will also notice that the edges of the talking head become
pixilated. This slider adds a bit of feather to smooth the edge.
Tip:
You don't have to use the sliders to make these adjustments. You can
also click the values—the blue numbers—in the percentage area and
drag to change them. This is a neat trick but I would suggest using
the sliders until you are more comfortable with the interface. You
can also double-click the values and enter them manually.
Play around with these
values until the appearance looks best to you (see Figure 13).
Figure 13.
Experiment with the settings to obtain the best results
