limiting the pixels that are changed, the Chromakey effect applies the matte to the alpha
channel, selectively making pixels transparent.Working with the Opacity effect
You can adjust the overall opacity of a clip using keyframes on the Timeline panel or in the
Effect Controls panel.
1. If it’s not already open in the Timeline panel, open the sequence Desert Jacket. This
sequence has a foreground image of a man in a jacket, with a background image of a desert.
2. Increase the height of the Video 2 track a little. You can do this by dragging the dividing
line in the track header (at the far left of the Timeline panel) between Video 2 and Video 3.
You can also hover the pointer over the Video 3 track header, hold Option (macOS) or Alt
(Windows), and scroll your mouse wheel.
3. Open the Timeline panel Display Settings menu, and make sure Show Video Keyframes is
enabled.Now you can use the rubber band (the thin horizontal white line on clips) to adjust the
settings and keyframe effects. There is only ever one rubber band per clip.You can specify which control is adjusted with the rubber band by right-clicking the small
fx badge , which changes color if an effect is applied to the clip or if a fixed effect is
adjusted.By default, the rubber band on visual clips controls Opacity. As you learned earlier, the
default for audio clips is volume.
4. Try dragging the rubber band up and down using the Selection tool on the clip on Video 2.
Try to set it to exactly 50%.
Tip
When adjusting the rubber band, after you begin dragging, you can hold Command
(macOS) or Ctrl (Windows) for fine control. Be careful not to press the modifier key
before clicking or you’ll add a keyframe instead.