Channel combiner effect, Compound arithmetic effect – Adobe After Effects CS4 User Manual
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USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
Preserve Transparency
Ensures that the alpha channel of the original layer isn’t modified.
More Help topics
Blending modes and layer styles
Channel Combiner effect
The Channel Combiner effect extracts, displays, and adjusts channel values for a layer.
Note: You can use this effect to view any channel as a grayscale image by choosing the channel from the From menu and
choosing Lightness Only from the To menu.
This effect works with 8-bpc color.
for using the Channel Combiner effect
with the Levels effect to affect only the luma (detail) information in an image—or, conversely, to only affect the color
information in an image.
Use 2nd Layer
Retrieve values from Source Layer, which can be any layer in the composition.
From
Which values to use as input; the first several items in the menu are multichannel combinations of input and
output options, so they don’t require you to set a To value.
•
Saturation Multiplied uses the saturation value multiplied by the lightness value, where lightness is the minimum
distance to black or white. For example, a dark or light blue pixel has a lower value than a bright or pure blue pixel.
This option represents the most common view of the saturation value of a pixel.
•
Min RGB uses the lowest value among the red, green, and blue channel values.
•
Max RGB uses the highest value among the red, green, and blue channel values.
To
The channels to which to apply the values. Choose Red Only, Green Only, and Blue Only to apply the value to one
channel only and set the other color channels to zero. Choose Alpha Only to apply the value to the alpha channel and
set the color channels to 1.0. When you select Hue Only, the applied hue value is combined with 50% lightness and
100% saturation. When you select Lightness Only, the applied lightness value is combined with 0% saturation, which
then gives the hue no influence. When you select Saturation Only, the applied saturation values are combined with 0%
hue and 50% lightness.
Invert
Inverts (subtracts from 1.0) the output channel values.
Solid Alpha
Makes the alpha channel value 1.0 (complete opacity) throughout the layer.
Compound Arithmetic effect
The Compound Arithmetic effect mathematically combines the layer to which it is applied with a control layer. The
Compound Arithmetic effect is intended only to provide compatibility with projects created in earlier versions of After
Effects that use the Compound Arithmetic effect. Using blending modes is usually more effective than using the
Compound Arithmetic effect.
This effect works with 8-bpc color.
Second Source Layer
The layer to use with the current layer in the given operation.
Operator
The operation to perform between the two layers.
Operate On Channels
The channels to which the effect is applied.