Simulating Lighting Changes
The first part of the animation involves lightening the dark room. You'll use Opacity keyframes to animate the light.
- In the Timeline panel, click the Solo switch for both the Background Lit and Background layers (see Figure 5). Soloing the layers isolates them to speed up animating, previewing, and rendering.
Currently, the lit background is on top of the regular (darker) background, obscuring it and making the initial frame of the animation light. However, we want the animation to start dark, and then lighten. To accomplish this, you'll make the Background Lit layer initially transparent, and have it "fade in" and appear to lighten the background over time.
- Go to 5:00.
- Select the Background Lit layer in the Timeline panel and press T to reveal its Opacity property.
- Click the stopwatch icon to set an Opacity keyframe (see Figure 6). Notice that the Opacity value is 100%.
- Press the Home key to go to 0:00, and then set the Opacity for the Background Lit layer to 0%. After Effects adds a keyframe. Now, when the animation begins, the Background Lit layer is transparent, which allows the dark Background layer to show through (see Figure 7).
- Click the Solo switches for the Background Lit and Background layers to restore the view of the other layers, including Window and Window Lit. Be sure to leave the Opacity property for the Background Lit layer visible.
- Expand the Window Pane layer's Transform properties. The Window Pane layer has a Photoshop layer style that creates a bevel on the window.
- Go to 2:00 and click the stopwatch next to the Opacity property for the Window Pane layer to create a keyframe at the current value, 30% (see Figure 8).
- Press the Home key to go to the beginning of the time ruler, and change the Opacity property to 0%.
- Hide the Window Pane properties.
- To preview the animation, click the Play/Pause button in the Time Controls panel, or press the spacebar. The interior of the room transitions gently from dimly to brightly lit.
- At any time after 5:00, press the spacebar to stop playback.
- Choose File > Save.