motion mask
Only what moves. A frame-difference pass lights up everything that changed and leaves the still parts dark — the effect lives entirely in the gesture.
What it’s for
A long-exposure photographer freezes the building and lets the passing crowd smear into light. The motion mask works the same nerve. It compares each frame to the last and wherever the image changed — a hand, a head turn, a passing car — the mask goes to 1. Whatever held still stays at 0.
low suppresses the noise floor so sensor grain
and faint flicker don’t register as movement.
high saturates large motion so a fast gesture
reads as fully selected rather than a faint ghost.
gamma shapes the response curve between a twitch
and a sweep.
Reach for this when: you want motion-trails locked to the moving subject; a smear that respects stillness; a glitch that only fires when something actually happens on screen.
Where it lives in the app
Add from the Masks panel. The mask appears as its own layer
on the timeline; assign it to one or more effects by setting
their target to point at this mask layer.
Parameters
| Key | Range | Default | Effect |
|---|---|---|---|
low | 0–1 | 0.05 | Suppress noise |
high | 0–1 | 0.5 | Saturate large motion |
gamma | 0.1–4 | 1 | Curve |
Pairs well with
- echo / trails — the smear lives only on what moves, so a still face stays sharp while a waving hand drags light behind it.
- chromatic aberration — colour separation that only blooms during movement. The frame stays clean until something stirs.
- text-glitch — type that breaks up only while it animates, then settles clean once it lands.
- phosphor CRT glow — bright trails that linger like burn-in along the path of a gesture.