Keyframe

A keyframe marks a specific point in time where you define a particular value for a property, with the software automatically calculating intermediate values between keyframes through interpolation. In video editing, keyframes control animated effects like position, scale, opacity, and color changes over time. In 3D animation, keyframes define character poses at important moments. The computer generates the in-between frames, a process called tweening, creating smooth transitions from one keyframe state to the next.

Animating a title card in After Effects uses keyframes to control motion. At frame 0, you set a keyframe for Position off-screen to the left and Opacity at 0%. At frame 30, you add keyframes for Position at center-screen and Opacity at 100%. The software interpolates all frames between, creating a smooth slide-in with fade. Adding Easy Ease to keyframes changes the interpolation curve so movement starts slow, accelerates, then slows to a stop, feeling more natural than linear motion.