What Is Posterize Time in Adobe After Effects
The Posterize Time tool in Adobe After Effects is an effect and expression designed to alter the perceived frame rate of a layer or composition without changing the project's overall frame rate settings. By artificially limiting the number of frames displayed per second, it allows animators and video editors to create stylized motion effects, such as traditional hand-drawn animation on twos, stop-motion aesthetics, or retro video simulations. This guide covers how Posterize Time works, how it alters frame rates, and the primary ways to apply it to your projects.
How Posterize Time Works
In digital video, the frame rate determines how many still images are shown per second to create the illusion of fluid movement. A standard composition might run at 24, 30, or 60 frames per second (fps).
Posterize Time intercepts this playback by sampling the layer at a new, specified frame rate. If you have a composition running at 24 fps and apply Posterize Time set to 12 fps, the software holds each frame for twice as long, skipping the intermediary frames. The duration of the footage, audio, and timeline remains completely unchanged; only the visual update frequency is modified.
Posterize Time as an Effect
You can apply Posterize Time as a standard visual effect by navigating to Effect > Time > Posterize Time.
When added to a footage layer, solid, or pre-composition, the effect provides a single parameter: Frame Rate.
- Setting the value to 12 in a 24 fps composition mimics traditional 2D animation shot "on twos," where each drawing is held for two frames.
- Setting the value to 8 or 6 produces a choppy, retro, or stop-motion feel.
- Setting the value higher than the composition frame rate has no effect, as the layer cannot display more frames than the composition allows.
Applying this effect to an Adjustment Layer will force every layer underneath it to adopt the lower frame rate, making it an efficient way to stylize an entire scene instantly.
Posterize Time as an Expression
Posterize Time can also be written directly into property expressions
using the posterizeTime(framesPerSecond) syntax.
This approach targets individual properties rather than entire
layers. For instance, if you want an object to move across the screen at
a smooth 60 fps, but you want its rotation or a wiggle()
function to appear stepped and jerky, you can insert the expression at
the beginning of that property's code:
posterizeTime(8);
wiggle(3, 50);In this scenario, After Effects calculates the wiggle only 8 times per second, holding the value between updates, while any keyframed position coordinates on the same layer remain smooth.
Key Use Cases
- Mixed-Rate Animation: Animating graphic elements at 12 fps over live-action 24 fps or 30 fps background plates to integrate 2D character animation seamlessly.
- Stop-Motion Emulation: Giving clean 3D renders or digital vector illustrations the imperfect, tactile cadence of physical claymation or cut-out animation.
- Stylized Transitions: Temporarily dropping the frame rate during an action sequence, flash-forward, or impact frame to heighten dramatic tension.