Keyframe

In any animation tool, a property changes over time. A keyframe pins that property at a given moment: “at 0.5 s the title is 200 px to the left and invisible; at 1.0 s it is centered and fully opaque.” The software fills in every frame between the two keyframes, a step called tweening. Two keyframes make a move; three or more make a move with a change of direction or rhythm.

Keyframes are rarely spaced evenly. Animators cluster them where something important happens and add easing so the motion accelerates and settles instead of sliding at a constant speed. In traditional hand-drawn animation, “key” drawings played a similar role: the lead artist drew the important poses and assistants drew the in-betweens.

In a short explainer, timing is the message. A number that appears half a second before the narrator says it feels like a spoiler; one that appears half a second late feels sluggish. Keyframes are where that timing lives, so a well-keyed video lands each visual on the exact word it illustrates.

On a phone, viewers also need motion to be readable at a glance. Fewer, well-placed keyframes with clear start and end states usually read better than busy, constantly moving elements.

A narrator says: “Prices rose 12% in a year.” A clean keyframe plan could be: at the start of “Prices”, the bar chart sits at its old height (keyframe 1); on “rose”, the bar grows with an ease-out to its new height (keyframe 2); on “12%”, the label pops in with a small overshoot (keyframes 3 and 4). Four keyframes, one idea, perfectly synced to the voice.