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Adobe After Effects Help
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Channel effects
Use these effects to manipulate, extract, insert, and convert the channels of an image. The
channels themselves include the component color values (red, green, and blue), calcu-
lated color values (hue, saturation, and luminance), and transparency values (alpha
channel).
For more information, see the After Effects product section on Adobe's Web site.
Alpha Levels (PB only)
This effect increases or decreases the transparency of a matte. Use it to adjust pure black
or pure white areas of a matte to be semitransparent or to adjust grays (semitransparent
areas) to be pure black and white.
For more information, see the After Effects product section on Adobe's Web site.
Arithmetic
This effect performs various simple mathematical operations on an image's red, green, and
blue channels. The Operator option specifies the mathematical operation to perform
between the value you specify for each channel and the existing value of that channel for
each pixel in the image: And, Or, and Xor apply bitwise logical combinations of the
specified value; Add, Subtract, and Difference apply basic math functions using the
specified value; Max selects each pixel in the color channel that is less than the specified
value and sets it at the specified value; Min selects each pixel in the channel that is greater
than the specified value and sets it at the specified value. Block Above and Block Below turn
the channel off everywhere that it is respectively greater or less than the specified value;
Slice turns the channel off where it is below the value specified and turns it on where it is
above the specified value.
The Clip Result Values option prevents all functions from creating color values that exceed
the valid range. If this option is not selected, some color values may wrap around from on
to off, or vice versa.
Blend
This effect blends two layers using one of five modes. A crossfade is a standard transition
between two images: the original image fades out while the new image fades in. After you
blend layers using this effect, hide the layer you selected from the Blend with Layer menu
by clicking the video switch for that layer in the Timeline window.
Two images blended together to create a textured butterfly.
Note: You can create blends more easily and quickly using layer modes, but you can't
animate layer modes. The advantage of using the Blend effect is that you can animate it.
For more information on layer modes, see "Using layer modes" on page 166.
For more information, see the After Effects product section on Adobe's Web site.
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Applying Effects
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