Apple Final Cut Pro 7 - Manual (Page 1214)

For example: You have a title graphic that was created in Photoshop, so it has an alpha
channel already set up. When you import it into Final Cut Pro, the alpha channel is
recognized automatically. To create your title sequence, you edit the title graphic and a
background image into your sequence, so that the background image is on track V1 and
the title graphic is on track V2.
The alpha channel in the
graphics file makes the
areas around the text
transparent without
requiring you to change
any opacity settings.
The title graphic with the
alpha channel is in a
higher-numbered track.
Changing a Clip’s Alpha Channel Type
When you import a still image file, Final Cut Pro identifies the type of alpha channel and
sets the imported clip’s Alpha property appropriately. You should usually not change this
setting, except in rare circumstances where Final Cut Pro identifies an image alpha channel
as premultiplied black or premultiplied white and you are certain that the alpha channel
type is actually straight.
When you import a video file with an embedded alpha channel from third-party editing
and compositing applications, Final Cut Pro always sets the Alpha property to Straight.
In these cases, you can manually change or reverse the alpha channel setting if necessary.
To change a clip’s alpha channel type using the Item Properties window
1 Do one of the following:
• Select a clip in the Browser, then choose Edit > Item Properties > Format (or press
Command-9).
• Control-click a clip in the Browser, then choose Item Properties > Format from the
shortcut menu.
1214 Chapter 71 Compositing and Layering