Viewing Transparency
In the Footage panel, transparency always appears as black, as shown in Figure 25. However, if the black background isn't convenient, you can toggle the transparent areas to appear as a checkerboard pattern, or transparency grid (see Figure 26). To toggle transparency, click the Toggle Transparency Grid button (shown in Figure 27) in the Footage, Composition, or Layer panel. When the Toggle Transparency Grid button is selected, transparent areas appear as a checkerboard pattern; when the button isn't selected, transparent areas appear black in a Footage panel. (In a Composition or Layer panel, you can set the background to any color.)
Figure 25 In the Footage panel, transparent areas of the image appear as black.
Figure 26 You can make transparent areas appear as a checkerboard pattern (transparency grid). This technique also works in the Composition and Layer panels.
Figure 27 Click the Toggle Transparency Grid button to toggle between showing transparent areas as black (in the Footage panel, or as the specified background color in the Composition panel) and showing them as a checkerboard pattern.