Setting a Comp's Background Color
The default background color of compositions is black; however, you can change the background to any color you choose. Regardless of what color you make it, the background becomes the alpha channel when you output the composition as a still-image sequence or a movie with an alpha channel. Similarly, if you use the composition as a layer in another composition, the background of the nested composition becomes transparent (Figure 4.21) (see "Nesting Compositions," later in this chapter). And as with the Footage panel (see Chapter 3, "Managing Footage") and the Layer panel, you can also view the background as a checkerboard pattern, called a transparency grid.
Figure 4.21 The background of the comp (first image) becomes transparent when nested into another comp (second image). The result is the third image.
To choose a background color for your composition:
- Select a composition in the Project panel, or activate a composition in a Composition or Timeline panel.
- Choose Composition > Background Color (Figure 4.22), or press Shift-Command-B (Mac) or Shift-Ctrl-B (Windows).
Figure 4.22 Choose Composition > Background Color.
- In the Background Color dialog box, do one of the following (Figure 4.23):
- Click the color swatch to open the color picker.
- Click the eyedropper to choose a color from another window.
Figure 4.23 Click the eyedropper to pick a screen color, or click the swatch to open a color picker.
Click OK to close the Background Color dialog box.
The selected composition uses the background color you specified.