Tunnel Effect
Tunnel effect for video and photos: each frame is pulled into the last, so bright parts stream outward like you're flying down a tunnel. Add spin for a spiral.
How does the tunnel effect work?
It's a feedback loop, the digital version of pointing a video camera at its own monitor. Every frame, the effect takes what it drew last time, enlarges it slightly about the center, fades it a little and lays the new frame over it, keeping whichever is brighter.
Repeated many times a second, that leaves a trail of older copies streaming out toward the edges. Bright parts leave the longest trails, and dark parts get covered by them, so a light on a dark background turns into a streak of light rushing past.
The settings
Zoom is how fast the trail falls outward. This page opens on the Fast preset, Zoom 0.8, and the effect's own default is 0.3. Spin turns the trail as it goes, up to 180 degrees a second either way, which bends the streaks into a spiral. Decay is how quickly older copies fade: low leaves a long trail, and high keeps only a short one.
Spiral sets Spin to 45 and Long trail drops Decay to 0.05. Tunnel, the gentlest, keeps Zoom at 0.3.
What footage works best?
High contrast footage with bright subjects on dark backgrounds: concert lights, neon, sparks, a dancer in a spotlight. A bright, busy picture fills the whole frame with trails and turns to a white wash, so raise Decay to shorten the trails, or darken the clip first.
On a still photo, the trail builds up over the first seconds and then holds steady, so save it as a clip rather than a single frame. Screen Shake Effect after it adds a jolt on the hits, for a music video that feels like a rush.
Does it loop?
Not by itself, because each frame depends on everything before it. For a GIF, let the trail build, then cut the clip where it has settled, so the start and end look alike.