Setting Key Points (Apply Points Method); Single Key Point Method (One Color Pickup) - Adobe 25510629 - After Effects CS3 Professional User Manual

Setting Key Points (Apply Points Method)

Ultra provides two methods for setting the key using key points that you select. In general,
you should only need to use one of these methods if you do not have a reference frame that
shows only the color screen background with nothing in the foreground. If the background is
a consistent, saturated shade of green or blue, then you should use the Single Key Point
method. For more information, see
on page 79. If the color, brightness, and saturation of the background are not consistent
throughout the frame, then you should use the Multiple Key Points method. For more
information, see "Multiple Key Points Method (Color Spread)" on page

Single Key Point Method (One Color Pickup)

You should use this method if you do not have a reference frame for the input clip and the
keying background is well lit and consistent in color with no pronounced shadows or uneven
shading. For more information, see
session, see "Setting the key" on page 76
to set the key.
Unlike the other methods of setting the key, this method does not use a mathematical model.
Instead, this method samples a single color and subtracts that from the entire image, hence
the name One Color Pickup for the keying method.
To set the key
With the input clip as the active layer, click the Add Key Point tool
1.
Preview Monitor. If this tool's icon is not displayed, then the input clip is not the active
layer.
Click a single spot in the background to set the key point. Because the background should
2.
be a consistent color if you're using this method, it doesn't matter where you set the key
point. If there are minor irregularities in the background, don't set the key point near them.
Click the Apply Points button or press Ctrl+K.
3.
If necessary, fine-tune the key. For more information, see
4.
on page 84.
"Single Key Point Method (One Color Pickup)"
"Set Key" on page 78. If this is not the case for the current
to determine which of the other two methods to use
80.
below the Input
"Fine-tuning the Keyer settings"
Setting the key 79