Faster Grain in After Effects

The Grain (Film Grain) effect in After Effects can make your work look awesome, there's just one problem, it takes forever to render or preview. Here's a hacky workaround that works best for mograph art. It freezes the grain, so it doesn't have to render a new version on each frame.

1. Make a new solid. 50% gray.
2. Put your grain effect on it.
3. Posterize time down to 0 fps.
4. Choose mode: overlay