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Adobe After Effects CS4 User Manual

Page 396

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390

USING AFTER EFFECTS CS4

Effects and animation presets

Last updated 12/21/2009

Color depth
Many effects support processing of image color and alpha channel data at a depth of 16 or 32 bits per channel (bpc).
Using an 8-bpc effect in a 16-bpc or 32-bpc project can result in a loss of color detail. If an effect supports only 8 bpc,
and your project is set to 16 bpc or 32 bpc, the Effect Controls panel displays a warning icon

next to the effect name.

You can set the Effects & Presets panel to list only the effects that support the color depth of the current project. (See

Color depth and high dynamic range color

” on page 274.)

Render order
The order in which After Effects renders masks, effects, layer styles, and transform properties—called the render
order
—may affect the final result of an applied effect. By default, effects appear in the Timeline panel and Effect
Controls panel in the order in which they were applied. Effects are rendered in order from top to bottom in this list.
To change the order in which effects are rendered, drag the effect name to a new position in the list. (See “

Render order

and collapsing transformations

” on page 64.)

Adjustment layers
To apply an effect to only a specific portion of a layer, use an adjustment layer.

An effect applied to an adjustment layer affects all layers below it in the layer stacking order in the Timeline panel. (See

Adjustment layers

” on page 141.)

Andrew Kramer provides a video tutorial on his

Video Copilot website

in which he shows how to use an adjustment

layer to apply an effect to only a short duration and to only specific portions of a movie.

Expression Controls effects
Expression Controls effects do not modify existing layer properties; rather, these effects add layer properties that
expressions can refer to. (See

Expression Controls effects

” on page 653.)

Preventing edge clipping with the Grow Bounds effect
Because an effect is applied to a layer, the results of some effects are constrained to within the bounds of the layer,
which can make the effect appear to end abruptly. You can apply the Grow Bounds effect to a layer to temporarily
extend the layer for the purpose of calculating the results of other effects. This process is not necessary for newer
effects, which tend to be 32-bpc effects.

Managing effects and effect properties with scripts
Paul Tuersley provides a script on the

AE Enhancers forum

with which you can search compositions for effects and

turn them on or off.

Paul Tuersley provides a script on the

AE Enhancers forum

that makes synchronizing changes to effect properties on

multiple layers easier.

More Help topics

Plug-ins

” on page 641

Effects & Presets panel

” on page 392

Layer switches and columns in the Timeline panel

” on page 154

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