Light Trails
Smear bright pixels along a direction for single-frame long-exposure streaks.
Add Light Trails
Open an image or build the source composition first. Put this effect after the content it should process in stack processing order. Choose Optics → Light → Light Trails in the effects picker, or search for Light Trails with Cmd/Ctrl + F. Select the new layer in Layers to open its Effect Panel.
Set the still-image streak
Set Threshold for the bright regions that streak, then Angle and Length for their direction and reach. This version constructs streaks from the current frame.
Shape the tail
Use Decay and Knee for the fade, Intensity for brightness and Samples for smoothness. For trails from actual movement across frames, use Temporal Motion Trails.
Compare and finish
Toggle the layer eye to compare with the incoming composition. Use the Effect Panel footer for opacity and blend mode, or add a mask to limit the affected area. In Video or Live, use the function menu on a supported control to add keyframes or a driver.
Control reference
Show individual controls
| Control | What it does | Values and animation |
|---|---|---|
| Angle | Rotates the axis along which source highlights are sampled into light trails. | 0° to 360° Default: 0° Continuous keyframes |
| Blend | Chooses how the generated light trails combine with the source, such as Screen or Add. | Screen / Add Default: Screen Not keyframeable |
| Decay | Brightness retained by successive light-trail samples. | 0 to 1 Default: 0.85 Continuous keyframes |
| Threshold | Minimum source brightness that contributes to a light trail. | 0% to 100% Default: 70% Continuous keyframes |
| Intensity | Scales the brightness of the generated light trails. | 0 to 4 Default: 1 Continuous keyframes |
| Knee | Width of the soft brightness transition around the light-trail highlight threshold. | 0 to 0.5 Default: 0.08 Continuous keyframes |
| Length | Maximum distance over which highlights are gathered into a trail, in the selected Length unit. | 0 to 20 %; 1 to 500 px (typed input: 1 to 2000) Default: 8 % Continuous keyframes |
| Samples | Number of source samples gathered along each spatial light trail; more samples make trails smoother at greater processing cost. | 1 to 256 Default: 64 Discrete keyframes |