Fog inversion layer

[logsquared]

Anyone ever run into this problem?....

I had a gig in a mid sized gymnasium with about 50' ceiling height. The image of the laser on the rear wall was very bright. The room was sufficiently dark. But the beam effects were very weak. I am thinking what the heck, so I pumped more fog into the room. Total pea soup... still weak beams. I figured the fog must not be getting up that high. But from the ground (where i was standing) it looked like the whole venue was full of fog, top to bottom. Went out to the trailer and brought in a fan. Within a few minutes the fog was stirred up and the beams looked great. I have seen fog stratify in rooms before but never completely stay below 10 feet.

[White-Light]

Could it be you just thinned the fog out with the fan?

There's a very fine line between too little and too much fog, and too much weakens the beams considerably. It can be just as bad if not worse than too little. A pea soup will give very very weak beam effects with all but the most powerful of lasers.

I'm not in anyway saying it can't happen, but I've never heard of a temperature inversion indoors. Therefore I'm guessing if you pea souped it you simply over smoked it and the fan dispersed and thinned the fog.

[VDX]

... yes, had the same with fog, fumes and very light dust too - it's mostly the weight difference between the clear air and the fog/fume/dust medium.

- with the fumes or the dust cloud: they wer lighter than air, so stayed roughly 3 meter above the floor
- with the heavier fog: this was the other way round ...

Viktor

[logsquared]

Could it be you just thinned the fog out with the fan?

There's a very fine line between too little and too much fog, and too much weakens the beams considerably. It can be just as bad if not worse than too little. A pea soup will give very very weak beam effects with all but the most powerful of lasers.

I'm not in anyway saying it can't happen, but I've never heard of a temperature inversion indoors. Therefore I'm guessing if you pea souped it you simply over smoked it and the fan dispersed and thinned the fog.

The beams looked extremely weak even directly in front of the projector ruling out too much fog.

[frostypaw]

I remember seeing this all the time in the days of smoking it up with friends, sometimes it does just stratify out and you stand up and through a layer to clear air above. OK not scientific, but seen so regularly it just registers as an amusing thing that happens now - I'd entirely expect it in any indoor space with enough still air.

[catalanjo]

@frostypaw ... I am pretty certain you were all extremely "stratified"
Cheers

[frostypaw]

Reach for the lasers

My once full-time lighting buddy likes big fans for haze, doesn't trust natural air flow. He's all for having a proper haze machine with big fan and a separate burst mode fazer type to use more straight at the beams to give the scrolling smoke curls effect - it does work very well but I need a more controllable fazer or a larger laser playspace.

[catalanjo]

Nice image !
I agree with your mate..except I like shooting out a huge roll of faze thru a big centrifugal fan from the laser emplacement like a tidal wave ... with a few short bursts of xenon strobe lights to heighten the effect ...specially when changing from graphics to beam work...if the sound is properly synced . punters often actually duck down when this happens!
Cheers