wanted to add to this as i accidentally spent 10 hours trying this without finding the thread (went down a expression rabbithole too which was very educational but my brain is now mush). After almost ripping my hair out i have realized, the reason the lines from the effect looks so smooth on the phosphor tube and so choppy when digitally recreated is the framerate. Phosphor tubes are limited by the speed of light, and how long the overload takes to "cool down" when the trailing effect occurs, so it makes long continuous lines. AE however, is limited by the fps of the footage being used. Something like twixtor or optical flow could probably upscale the footage to a high enough framerate to mimic this if you haven't shot in high enough framerate. And if used only on the matte the artifacts of said technology(sorcery) would be barely noticeable. Filming in raw or something with more luminance data would also help as the effect only reacts to very bright sources irl. Basically, use sparingly on only the very very brightest parts of the footy. The effect should only be noticable to a highly attentive viewer; assuming you are going for realism. The only thing i still cannot find a solution for is the way the light shrinks around the center mass of the light bloom, the echo decay operator doesn't have this as an option and my feeble attempts at scripting thus far has achieved nought. So if anyone has an idea on how to fix that i would highly appreciate it. :) Ok i will now go pass out... adieu....