Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 96

Convert a merged footage item into a composition
When you import a layered file, such as a Photoshop or Illustrator file, as footage, all of its layers are merged together.
If at any time you decide that you want access to the individual components of the footage item, you can convert it
to a composition.
• To convert all instances of a footage item, select it in the Project panel and choose File > Replace Footage > With
Layered Comp.
• To convert only one instance of the footage item, select the layer in the Timeline panel, and choose Layer >
Convert To Layered Comp.
Note: It may take a few moments to convert a merged footage item to a layered composition.
Preparing and importing Photoshop files
Because After Effects includes the Photoshop rendering engine, After Effects imports all attributes of Photoshop
files, including position, blending modes, opacity, visibility, transparency (alpha channel), layer masks, layer groups
(imported as nested compositions), adjustment layers, common layer styles, layer clipping paths, vector masks,
image guides, and clipping groups.
To see a video tutorial on importing Photoshop files, visit the Adobe website at www.adobe.com/go/vid0252.
A very convenient command within After Effects is Layer > New > Adobe Photoshop File, which adds a layer to a
composition and then opens the source of that layer in Photoshop for you to begin creating a visual element, such as
a background layer for your movie. The layer in Photoshop is created with the correct settings for your After Effects
composition. As with many of the Creative Suite applications, you can use the Edit Original command in After
Effects to open a PSD file in Photoshop, make and save changes, and have those changes appear immediately in the
movie that refers to the PSD source file. Even if you don't use Edit Original, you can use the Reload Footage
command to have After Effects refresh its layers to use the current version of the PSD file. (See "Create a layer and
new Photoshop footage item" on page 141 and "Edit footage in its original application" on page 69.)
Adobe Photoshop supports a transparent area and one optional layer mask (alpha channel) for each layer in a file.
You can use these layer masks to specify how different areas within a layer are hidden or revealed. If you import one
layer, After Effects combines the layer mask (if present) with the transparent area and imports the layer mask as a
straight alpha channel.
If you import a layered Photoshop file as a merged file, After Effects merges the transparent areas and layer masks of
all the layers into one alpha channel that is premultiplied with white.
If the layered Photoshop file contains clipping groups, After Effects imports each clipping group as a composition
nested within the main composition. After Effects automatically applies the Preserve Underlying Transparency
option to each layer in the clipping-group composition, maintaining transparency settings.
When you import a Photoshop file as a composition, vector masks are converted to After Effects masks. You can then
modify and animate these masks within After Effects.
After Effects also supports blending modes and layer styles applied to the file.
Photoshop files can even contain video and animation layers. After Effects can import these files just as any other
Photoshop files, either as a footage item with all layers merged together or as a composition with each Photoshop
layer separate and editable in After Effects. (Working with Photoshop video layers requires QuickTime 7.1 or later.)
Photoshop layer groups are imported as individual compositions.
AFTER EFFECTS CS3 90
User Guide