Using Keyframes to Set Transparency

In order to vary the amount of transparency, whether it's just a simple dissolve-like effect from 0% to 100% or customizing each frame for some off-the-wall effect, you need to set these different variables using keyframes. If you want to vary a clip's transparency at different points in the clip's duration, you need to add keyframes at those particular points in the timeline.

To use keyframes to adjust individual transparency levels, do the following:

1. Layer two tracks of video, and expand the view of Track 2 as described in the section "Layering Multiple Effects on a Single Clip."

2. Click the Display Opacity Rubberbands button to view transparency levels, as shown in Figure 6.9.

   Figure 6.9. Click the Display Opacity Rubberbands button to view transparency levels. You can toggle between views using the Display Keyframes button and the Display Opacity Rubberbands button.

   

3. Click one of the little red boxes on the transparency line, or just click anywhere in that track to add a new one. The cursor should change to a finger icon.

4. Move the box up or down to change the level of transparency at that specific point in time.

tip

Hold down the Shift key while dragging the keyframe box to specify an amount as a percentage.

Notice the ramping effect that occurs when you lower the position of only the first keyframe (see Figure 6.10). Lowering the first keyframe all the way down gives you a nice smooth fade-in of the image on Track 2.

Figure 6.10. Lowering the first keyframe creates a smooth fade-in from completely trans parent to fully opaque.

note

All effects need a minimum of two keyframes one at the beginning and one at the end of the clip. You cannot delete these keyframes.

tip

You can go back and fine-tune the position of any keyframe at any point in your editing session.