fog/haze without a fogging machine?

[Insanity]

Pictures with lots of detail hide the damage, but when you take a light coloured background, the damage becomes clear... Look inside the red rectangle...

Be warned, lasers can do the same damage to video projectors and more importantly eyes...

[Insanity]

Yes, assuming you are using Pangolin software for control... If you are, you can set a Beam Attenuation Map to mask out that area of the scanfield, then no laser will hit the lens... That's what we do at gigs to protect video projectors. Basically, stick the lens cap on, turn laser on at low power, draw a circle on the lens cap and then set the BAM to zero output for that area...

[colouredmirrorball]

In LSX, that feature is called "Safety Zones" in the DAC settings.

But for a DMX or SD card-based laser... don't put the camera in the beam path?

[AnAnonymousParty]

What not to do:

Circa 1976, bunch of teenagers in a band covering the the first few tracks from Dark Side of the Moon. Had a 'light show', a dangerous switch/dimmer contraption that managed four towers each with 8 150w flood lamps of different colors, switchable/dimmable by color, by tower front/back, left/right, etc. Needed fog effects for Pink Floyd tunes. Problem: Teenagers in 1977 can't afford fog machine. Can afford fog juice. One member of the group knows dad has propane fired bug fogger. Idea: put fog juice in bug fogger, problem solved. Kinda. New problem: when warming up the 'fog machine' prior to use it's too easy to to get it a little too hot and fog juice ignites. Solution, borrow fire extinguisher from same dad 'just in case'.

Now same band is playing in a big 'battle of the bands' and, fog is cued and everything seems to be going well ... until fogger being shot thru drum kit turns into flame thrower (band doesn't know this as it's going on behind them. Drummer does but, being a drummer, keeps playing as the show must go on). Fog operator somehow has presence of mind to kill the fogger and fire the (CO2) fire extinguisher thru the drum kit putting out the burning shag carpet on the homemade drum risers (I said it was the 70s). Set ends while crowd goes nuts.

Mark Klose from KSHE radio is ecstatic, "Guys, that was the coolest thing I've ever seen! How did you do that?" We'd no clue what he'd seen, which was described as at first a billowing cloud of smoke coming out of the drum set, which was then engulfed by a ball of flame followed by perfect dry ice fog that poured out over the stage for "Breathe reprise". As the band played on . . .

Ask me sometime how I know that if a little flash powder is good, then a lot is not better.

[Galvonaut]

Sometimes it seems that these often dangerous errors are the making of people or the beginning of new trends having inspired others (hopefully a bit safer)!

It sounds like you've been to the party, AnAnonymousParty

Keith

What not to do:

Circa 1976, bunch of teenagers in a band covering the the first few tracks from Dark Side of the Moon. Had a 'light show', a dangerous switch/dimmer contraption that managed four towers each with 8 150w flood lamps of different colors, switchable/dimmable by color, by tower front/back, left/right, etc. Needed fog effects for Pink Floyd tunes. Problem: Teenagers in 1977 can't afford fog machine. Can afford fog juice. One member of the group knows dad has propane fired bug fogger. Idea: put fog juice in bug fogger, problem solved. Kinda. New problem: when warming up the 'fog machine' prior to use it's too easy to to get it a little too hot and fog juice ignites. Solution, borrow fire extinguisher from same dad 'just in case'.

Now same band is playing in a big 'battle of the bands' and, fog is cued and everything seems to be going well ... until fogger being shot thru drum kit turns into flame thrower (band doesn't know this as it's going on behind them, drummer does but, being a drummer keeps playing as the show must go on). Fog operator somehow has presence of mind to kill the fogger and fire the (CO2) fire extinguisher thru the drum kit putting out the burning shag carpet on the homemade drum risers (I said it was the 70s). Set ends while crowd goes nuts.

Mark Klose from KSHE radio is ecstatic, "Guys, that was the coolest thing I've ever seen! How did you do that?" We'd no clue what he'd seen, which was described as at first a billowing cloud of smoke coming out of the drum set, which was then engulfed by a ball of flame followed by perfect dry ice fog that billowed out over the stage for "Breathe reprise". As the band played on . . .

Ask me sometime how I know that if a little flash powder is good, then a lot is not better.

[aricha]

Get a little piece of dry ice, put it in hot water and use a small fan to spread the clean safe haze.

[badger1666]

Please don't get tempted to use the fog in a can , you will regret it.
It's awfull stuff ,it will leave everything in the room oily and sticky , a noob mistake I made years ago

[Fearless]

Overheating glycerol in a frying pan can produce formaldehyde, which is quite toxic, especially to the eyes. Just my 2 cents.

[The_Doctor]

Overheating glycerol in a frying pan can produce formaldehyde, which is quite toxic, especially to the eyes. Just my 2 cents.

Fog fluids are usually polyethylene glycol solutions in water, not glycerine but I take your point. None of these fluids should be overheated. Formaldehyde has a 'characteristic pungent, irritating odor' as stated on Wikipedia. Think 'hospital smell' and you'll be ready the moment it becomes detectable at all, it's very familiar to nearly everyone.

Anyway, staying with glycol fluid is the way to go, and I described how hot to make the frying pan. Hot enough to make water droplets run across it as beads, instead of easily spreading and hissing to steam immediately, BUT NO HOTTER. Actually you get a bit of leeway but if it starts to smell like a soldering iron getting hot, it's too hot. If the glycol coming off makes clean white fog leaving no deposits, and the smell is that usual heavy sweet smell, you're in business. No matter what you do, there should be some room ventilation.

If it is done as I describe it, the result is extremely similar to a proper fog machine, the only thing lacking is a directional nozzle, and convenience, and safety (which is still no worse than any electric cooker). Some people might say that you get less fog per drop of fog fluid, but watch it happen, it all becomes fog. Any difference in efficiency is very marginal, as you'll find out very fast if you try to drop too much in the pan! The greatest risk is reducing visibility to zero while you're standing next to a hot cooker hob.

EDIT:
Nice page about fog fluids here:
http://www.bigclive.com/smoke.htm

[csg]

if you have access to a temperature probe / infra-red temperature gun, the typical optimal smoke machine vaporising temperature varies from 220 deg. Celsius for quick dispersing fluids through to around 325deg. Celsius for long hang fluids. both applicable to glycol only.