Does anyone know of an effect or plugin that will make pixels above a setable luminence threshold persist for a setable amount of time/frames?
Here's an example of this type of effect (go to 3 minute mark):
Simply search for "light painting" on the web. Tons of tutorials for that. Has nothing to do with plug-ins (well, mostly), but with how you shooot things and/or accumulate frames using effects like Echo or time-remapping in combination with channel effects. It's about technique and workflow methodology, not plug-ins
These Aharon Rabinowitz light writing tutorials are older but they should still be relatively valid for CS6. They may give you some ideas for ways of making artificial light writing.
Thanks, but that seems to be a way to fake the light painting effect. My plan is to film my subjects (clad in glo-sticks) with 360 degree shutter and trigger a flash occasionally. I'll duplicate the layer, add curves to isolate the bright points (glo-sticks), and use the echo effect to give the persistance. The hope is to get the light streaks along with frozen shapes when the flash fires. I'll have to be careful to only hit the subjects and not background with flash.
Yeah those tutorials are definitely for faking light painting. I'm all for the analog method whenever possible though, so that sounds like your best bet. Definitely do several tests with the flash first. All you gotta do is remember the inverse square law and be sure to leave enough space between your subject and the background so the light falls off before hitting it.
I would approach this project by filming your subjects moving light sticks around against a black background. Then I would experiment with echo to make the light trails.
I think that's your best option with real footage.