Apple Motion 2 Getting Started - Manual (Page 151)

Chapter 5 Extra Credit 151
Once the layers are positioned, a keying filter is applied to the blue screen element. The
keying filter you select depends on the type of element with which you are working, as
different filters yield better results on some types of shots than others. For more
information on the keying filters, see Chapter 9, “Using Filters,” in Motion Help.
Once the color key is pulled and refined, the composite is complete.
To key a blue screen image:
1 Import the blue screen image and the background image.
2 In the Layers tab, position the blue screen image above the background image.
Note: You can also use the Bring to Front/Send to Back and Bring Forward/Send
Backward commands in the Object menu.
3 In the Library, select Filters > Keying.
4 Select the Primatte RT keying filter and drag it to the blue screen image in the Canvas
or Layers tab.
The Primatte RT filter is added to the image and the blue color is automatically
removed, creating transparency in the formerly blue area (an alpha channel is created).
As a result, you can see the background on which the elephant is composited.
Final composite
2505.book Page 151 Wednesday, June 30, 2004 5:58 PM