Apple Color 1.5 - Manual (Page 354)

• Constant: Constant keyframes perform no interpolation whatsoever. All effects change
abruptly to the next keyframed state when the playhead reaches the next constant
keyframe. Constant keyframes are useful when you want an effect to change
immediately to another state, such as increasing the contrast to simulate a sudden
lightning strike flashing through a window.
By default, all new keyframes that you create are smooth, although you can change a
keyframe's interpolation at any time. Changing a keyframe's interpolation affects only
the way values are animated between it and the next keyframe to the right.
To change a keyframe's interpolation
1 Move the playhead to the keyframe you want to change.
2 Choose Timeline > Change Keyframe (or press Control-8).
354 Chapter 14 Keyframing