Strobe, echo and posterise time effects in Video
Video by Zaweba's time effects, strobe, echo and posterise time, play with how frames follow each other. What they do and the shots they suit best.
Video is a series of still frames shown quickly enough that the eye sees movement. Time effects play with that sequence instead of with colour or shape. Video by Zaweba has three of them, strobe, echo and posterise time, and while the list is short, each one changes the feel of movement in a way no colour grade can.
Echo
Echo blends earlier frames into the current one, so anything moving leaves a trail of ghostly copies behind it. A dancer's arm becomes a fan of arms, car lights stretch into streaks, and a person walking past leaves a fading line of themselves. The look is strongly associated with music videos and dream sequences.
It works best with a clear subject moving against a still background. If the camera is moving too, everything echoes and the frame becomes a smear, which can still be the effect you want, but is harder to control.
Strobe
Strobe makes the picture flash, imitating a strobe light. It is energetic and abrupt, suited to club scenes, beat drops and moments of shock. Because it flashes, keep it short, and be considerate of viewers who are sensitive to flashing images. Long, fast strobing is uncomfortable for many people and can be harmful to some, so use it sparingly and keep warnings in mind if you publish widely.
Posterise time
Posterise time holds each frame for longer, so the motion becomes choppy, like a low frame rate. It can make live footage feel like stop motion or hand drawn animation, give a jittery nervous energy to a scene, or match footage to a stylised animated look. Combined with the cartoon or pencil sketch effects, it does a decent job of faking an animated sequence.
Where time effects sit in the app
In the Effects tab, effects that work across time carry a time badge, so you can find them and know what they will do before applying them. They are applied like any other effect: to a clip, to a whole track, to a source file wherever it is used, or to an adjustment layer above several clips.
They are different from speed changes. Changing a clip's speed, or ramping speed with keyframes in the Inspector, changes how quickly time passes. Time effects keep the clip's timing but change how its frames are shown. You can combine the two, for example slowing a clip down with optical flow and then adding echo, for a smooth, flowing trail.
Thinking about when to use them
Time effects grab attention, which is both their strength and their risk. They suit moments you want the audience to notice: a chorus, a fight, a memory, a drug haze in a drama, a title sequence. In the middle of a calm interview they feel like a mistake.
They are also good transitions in disguise. A burst of echo that peaks at a cut can carry the eye from one shot into the next. Keyframing the effect's strength up to the cut and down after it is an easy way to do that.
Getting a good result
Watch them at full speed. A time effect often looks odd on a paused frame and fine when playing, or the other way round. Preview the section in real time before you judge.
Choose footage carefully. Clips with clean, deliberate movement give the clearest echoes and the most interesting posterised motion. Shaky handheld footage makes all three effects messier, so stabilising first can help.
Lastly, think about the final frame rate. Posterise time in particular interacts with the timeline's rate, and testing a short export on the target platform is wise before you commit.
Time effects in Video by Zaweba are a small set, but they open up a way of thinking about footage that goes beyond colour and shape.
