Club show in NY, audience scanning info

[dsli_jon]

...The post on ebay was saying that it was safe and ready for use...

..Now you know the truth...

..and i could never afford to rent a laser from a certified/professional/legal companies.

Friendly pro-tip: You should never price your services so-low, that you cannot afford to do this, and still make something for your effort.. If a promoter offers less, tell them to stick it.. they do not deserve your work - and you do not deserve the 'risk'.. (ie: What-happens if your Chino-box craps-out, and the promoter decides to sue you, because you were hired for lasers / didn't deliver / he claims his 'event was ruined by you', blah, blah... Even if total-bs, you'd still need to spend $$$ to *defend* yourself.. This might not be 'relevant', now, if You, only, are 'running the show', but.. Always think 'down the road'...)

.I just ask you to understand my point...

..and You, in-kind, ours (collectively.. Start here, http://www.photonlexicon.com/wiki/in...fety_Overviews ..ask lots of questions, stick to the 'high-road', and you'll have lots of success - long-term..

ciao..
j

[mixedgas]

Meanwhile, back at the ranch....

Attached picture should sum it up. That is a retinal picture from another forum where a member took a direct hit from a static beam from a 1 watt laser pointer. He lost 40% or so of his central vision. He describes it as feeling no pain, then he cannot see, then what he could see had a red-orange tint from the blood filling his eye.

Factoid, There really is not a good legal mechanism in place to find or report laser injuries.

Steve

[Photonbeam]

After many decades of working with high powered lasers I have a few suspicious lesions on one retina, but not on the fovea. I remember an incident in the '70's where a person took a hit from a pulsed laser. He was actually wearing safety glasses but they didn't seal all the way around. The laser pulse came from behind and reflected off the inside of the safety glasses back into his eye. He described it as a "pop" sound/sensation followed by what looked like someone dumping blood and ground black pepper into his field of vision. Then he went into shock.

[White-Light]

After many decades of working with high powered lasers I have a few suspicious lesions on one retina,

By lesions do you mean possible cancer? I've never heard of cancer of the retina but have heard of studies where lesions were mentioned but never fully understood exactly what they referring to, ie burnt cells or cancers.

[Stiffler]

After many decades of working with high powered lasers I have a few suspicious lesions on one retina, but not on the fovea. I remember an incident in the '70's where a person took a hit from a pulsed laser. He was actually wearing safety glasses but they didn't seal all the way around. The laser pulse came from behind and reflected off the inside of the safety glasses back into his eye. He described it as a "pop" sound/sensation followed by what looked like someone dumping blood and ground black pepper into his field of vision. Then he went into shock.

I got queasy reading this.

[Photonbeam]

By lesions do you mean possible cancer? I've never heard of cancer of the retina but have heard of studies where lesions were mentioned but never fully understood exactly what they referring to, ie burnt cells or cancers.

No eye cancer here. Just one or two tiny black dots that may or may not be laser burns. I don't see them in my vision - they showed up in retinal photographs.

[White-Light]

OK thanks for clearing that up, you had me a bit worried there. I'd never heard of cancer caused by visible light exposure only UV but when people mention lesions, you instantly think cancer as that's how its usually described. I was starting to almost question my own future laser usage if exposure could lead to retinal cancer as for me that's when the risks of beautiful light shows exceed the benefits.

[mixedgas]

405 and 445 worry me sometimes. Both wavelengths do not exist in great amounts in natural light. Shifting off the tungsten spectrum to the blue/yellow led spectrum for home lighting also worries me. There is a reason manufacturers are scrambling to emulate the solar/tungsten spectrum in LEDs. So far studies with 488 indicate that a shift in green vision acuity results.
Complete studies on 445 are a few years out.

As for safety, I worry more then most of you for a reason. The day job is pulsed tunable lasers at a few millijoules and 10 Hz, to Industrial at 16 joules per shot at 50 Hz or more. We also do a few picosecond lasers running at 80 MHZ with 20 watt average power. These ALL will start drilling a aluminum mount with a unfocused beam, with one pulse. I've already blown the anodizing off a mount while learning to adjust. Glasses are a last resort at those powers. If I can see green creeping around in my goggles, I've already set myself up for trouble. That is when I stop.

At work, we insert doubling crystals on sticks into our beampaths as a way to see what's going on. At these peak powers, we don't even need to tune the doubling angle much, hand held is enough. So the scary thing still is a repurposed lab laser being used for shows. I'm waiting to see a used modelocked fiber laser show up in a club. It is only a matter of time.

This is why you see me champion such a pro safety attitude, even if I'm loosing the game (well I've already lost) against the imports. I deal with the nasty stuff on a daily basis, week after week.

Powers are creeping up, and 4 watts, in a club, at zero distance is a retinal burn, likely to happen, not guaranteed. Luckily what is saving us is the poor beam quality and lousy divergence of diode sources.

Do what this Meebles guy does with a ion laser or OPSL and watch the lawsuits rack up. At some point powers will climb to levels where we see "events".

Steve

[White-Light]

I've been in a pub tonight where they were running a 445nm laser source right into the crowd, nearest person maybe 2 metres. I didn't see what type it was as I didn't want to get into the beams knowing it was probably 500mw minimum given the source. The beam looked fairly fat on the wall but there was no way I was getting into it.

[JasonB]

405 and 445 worry me sometimes.

Hi Steve,

Also thought I read here (maybe you posted it) that 445nm is more readily absorbed by the retina, which makes it even more dangerous. Is that correct ? On my personal hobby rig I added a switch to be able to shut off the 1 Watt of 445; I only use it under ideal conditions. When experimenting with writing shows, etc, I only enable the couple hundred milliwatts or red and green ....

Hopefully that will be safe enough (Oh, and I DO own and wear safety glasses for each wavelength when adjusting/aligning....).

A bit of fear I think is a good thing to remember to continually respect the lasers