Really Cool Property of Scrims


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For our production of Urinetown, we've hung a black scrim in front of the cyc to dull it down a bit. In doing this, we've discovered a really, really cool property of scrims. When heated, by lights, they move, giving the effect of an animated cyc. We have a tower center stage on the second level, so we have hidden a vertical boom behind it with S4 pars & scrollers behind that, so that we can shine light out from behind the tower of the UGC headquarters (for those of you who know the show, that's what the tower is in our set design). Whenever the cyc pars kick on, the scrim moves all over the place. It's subtle, but absolutely amazing, and fitting with the production concept. Also, whenever we shine the cloud gobos on it, it moves, which works in our favor, or the river gobos or the zip strips that are shooting up from below. It's pretty insanely cool.

Just sharing an accidental side effect that turned in to a very, very cool animation effect.


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Premium Member
hmmm I might try this tomorrow.... Gives me a chance to setup a few zip strips to light our scrim from bellow too.


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It's got the lightweight pipe in (plastic PVC instead of narrow steel) because it's hung approx 8' off the deck instead of almost touching the floor. I also think that it's because the S4 pars that are blasting it from behind this column are less than 3' away (aka pretty fine concentration of a 575W lamp (accounting for the enhanced aluminum reflector, we don't have MCM's) over abnormal areas because they aren't a full cyc wash).

Have you ever seen an application where S4 pars with MFL lenses were blasted almost straight at the scrim from less than 3' away? These are almost always n/c during the show, the scrollers are rarely used. I find it pretty weird myself, but that's a set design thing.


CB Mods
It is a great physics lesson. Heat up air, air rises. Cooler air is pulled in front of the heat source due to decreased pressure and the cycle starts again. If you were using ground cycs and running them very hot through the show with your scrim piped only with PVC you probably would have the problem where the lights would suck the scrim into them due to the thermodynamics.

In your situation where you have the lights between a set piece and the scrim, you have made a kind of chimney so the hot air accelerates up and the cooler air that gets pulled in ripples your scrim.


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Did you have the scrim piped? I have never seen a correctly piped scrim move.

I have never seen a correctly piped scrim move either, if you wanted the effect not to exist any more (IE theres a show that it dosen't work for) get some thin metal black pipe.

However, thats a very intersting effect, and I'm glad it works well for your show!

Its very common to put a cyc behind a black scrim, mainly because this way if you turn the cyc lights off, the cyc dissapears, as opposed to being a bright piece of white fabric bouncing all the light off of it.

You reminded me of a time that I hung a star field (made out of christmass lights, we were on a budget) behind a blue shark-tooth scrim. If you moved your head slightly while sitting in the audience the stars seemed to twinkle slightly. I assume if you got the scrim to move on its own as you talk about, the effect would have been even better.

I'd love to see a video of the effect. Very neet idea!
hmmm I might try this tomorrow.... Gives me a chance to setup a few zip strips to light our scrim from bellow too.
I don't think we have enough bulbs to set up even one of six Altman ZS-3 we have sitting around. What is it 30 bulbs into one light and we have only 12 bulbs, if we get 28 more bulbs you play around with it. But also I think the people that set up our auditorium set the scrim up right even thought that is a miracle for things to be done right in projects that are done by the 'lowest bidder'

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