Audience Scanning??

[Pangolin]

WOW, quite a bit of activity and discussions about Audience Scanning -- unfortunately, for the most part, by people who know nothing about it...

Allow me to respond to a few of the points brought up in this thread, if for no other reason, that I was mentioned by name.

The point I am making is that at some point the power of the laser entering the eye will be so little that it will not be able to do any damage. FACT
Jim

CORRECT!! There are international laser safety standards, including the IEC 60825-1 and ANSI Z136. These standards present tables and formulas for predicting the safe amount of laser light. The relative safety of a laser exposure depends on the wavelength, the power concentration (irradiance), the nature of the exposure (i.e. intraocular, scattered, skin exposures, etc.) and the exposure duration.

The standards are primarily based on experiments done by two biological physicists -- David Sliney and Myron Wobarsht. (I have met David Sliney on a number of occasions, and he and I have communicated several times about the topic of Audience Scanning). These guys did experiments on rhesus monkeys (subjects whose eyes are very close to those of humans), and also human eyeballs, to determine the safe levels of laser light. Since that time, the standards are periodically updated, based on real-world experiences in the field.

At present, each of the two standards I mentioned above take up about a half a rheum of paper each. So yes, there is a safe level of laser light, and this is well documented in the standards. It may be complex to understand, but there is a safe level...

There are also International Laser Safety Conferences that happen, typically every two years, where laser safety professionals from all around the world get together and present papers, and share their experiences.

A good friend of mine worked for a company called VISIX. They invented LASIK. Anyways he was an optical engineer on the project. Part of his duties was to do ablation testing on fresh pigs eyes. He would take the eyes and put them in a eye jig. He would then proceede to expose them to different levels of laser radiation. After exposure he would dissect them and document the damage.
He clinically concluded that any laser light entering the eye does SOME permanent damage no matter what.

Sorry, but this is not true. There is a safe level, otherwise the laser safety standards would be only one page, with a statement that says "Skipp's friend clinically concluded that any laser light entering the eye does SOME permanent damage no matter what". Also, there would be no need for International Laser Safety Conferences to happen every two years, because everyone would just intuitively know what Skipp's friend concluded.

Until you have done the clinical experiments and can prove to me that a laser in the eye is safe I will trust the VISIX optical engineer who did the tests.

Believe who you want. We will see who sees in 30 years.

Yes, well, I will believe David Sliney -- one of the two people who did all of the biological studies upon which the laser safety standards are based. I will also believe him when he has written to me in a private email that he doubts injuries from Audience Scanning are taking place. And I also believe John O'Hagan -- a close colleague, and someone who has done more research into the topic of Audience Scanning than probably anyone else in the world.

You are making a lot of really bold statements here Skipp, and frankly, your credibility is on the line.

Here on PL we name names. So with that said, I think it is only fair for you to provide the name of your buddy at VISIX, and also point us to papers he has written on the topic of laser safety. It would be even better of you get him to sign onto PL and make comments himself. Otherwise, it is easy for us to take your comments as "here-say", or at best, that you have misinterpreted what your buddy said in the first place.

After all, let me point out another fact. Lasers are used in supermarket scanners, and have been for the better part of 25 years. Actually that was one of the things that David Sliney talked to me about while we were discussing audience scanning. Laser safety professionals were concerned about the cumulative exposure that super market checkout clerks get after an EIGHT HOUR!! shift, each and every day. But after years of study, no eye damage has emerged.

Also, 10 years ago, my company commissioned a study to be done by a professional research organization in California (I would let you know the name, but I just don't have it off the top of my head and I am writing from home -- but the study and its results were presented at a previous International Laser Safety Conference, so it is public knowledge). The study looked at eye injuries that happened from audience scanning over, what was then the previous 20 years. The study looked at many sources, including government records from countries around the world, and also private and public information on the topic (for example, the database of laser accidents maintained by Rockwell). The study only discovered 5 injuries related to audience scanning over that time period, and, all of those injuries were caused by companies doing stupid things, like scanning the audience with a pulsed laser...

Now before you get all hoity toity on me. Know that I have done thousands of shows. All my friends are optical engineers and medical laser guys.

I always love it when people tell me how many years they have been doing something... My response is always the same: Just because you have been doing something for xxx number of years, doesn't mean you have been doing it RIGHT for that many years! It also doesn't mean that you have been doing it the only way possible for that many years.

Credibility must be earned -- it can't be bought by a simple statement of how many years someone has been doing something...

After all, I have been involved with lasers for over 22 years, and have numerous published papers (some on the topic of audience scanning) and numerous issued and pending patents. Does that NECESSARILY make me smarter than you? I would say probably but not necessarily...

I know a thing or two more than most about laser induced eye damage.

"A thing or two more than most" More than most of the people on PL? Exactly who are you including in this "most"?

Really this kind of statement has a flare of arrogance to it. From my perspective, the people who "know a thing or two more" than others are humble people, because they also know that there is always more to be known about any particular subject matter...

I have seen very large projectiles flying through the air at several events.
I found a half full coke can in one of my projectors after a show one night. It came in through the rail port.
I assume a large projectile might dislodge or ever break Bill's lens from his projector.

Well, the lens to which Buffo referred was a solid chunk of aluminum of glass that weighs (no kidding -- Buffo, back me up on this one) the better part of two pounds!! You can drive over it with a car and do nothing more than scuff the surface. In any event, the lens is more often placed inside the projector, before the scanners.

However, your anecdote brings up another few points:

First, any such blunt force trauma to the projector might very well change it's position. For example, the projectors used in your own shows that are pointing above the heads of the audience might be repositioned such that it is now projecting DOWNWARD into the audience. Don't forget that!!

Second, there is supposed to be an operator in control of the projector at all times, with a big, red, mushroom switch on a control panel. This is there so that the operator can respond to unforeseen events including "audience unruliness" (this wording appears in our variance application).

I am sure Bill did all of his home work.
IF everything works as calculated...
IF the electronics do not fail...
IF the diffusing lens stays in place....
IF the MPE levels are not met or exceeded....
IF the audiences pupils do not exceed 6mm dialation.
IF the show does not have to happen in the real world..
Then I would say audience scanning would be safe.

But those are a lot of ifs.

A lot of "ifs" indeed! I am glad you brought up this many "ifs", because I assure you, the CDRH also brought up all of these "ifs" and more!

Without getting into exactly how the system works, and how it is that we were able to accomplish a reliable response to all of these "ifs", lets just say that there are contingencies in place for all of these "ifs", and even some that are not on your list above .

Fore sure you probably will not PERMANENTLY injure any one with a 5mW laser.

LOL!! (where are those smiles from Aron when you need them)...

Well, I am glad that we can agree upon something.

And now the answer to why I am laughing so hard at your statement. The reason I am laughing is because we normally operate the system somewhere between 5mW and 10mW PER SQUARE CENTIMETER!! This is actually lower power PER UNIT AREA than a 5mW laser. The reason why our effects appear brighter than a 5mW laser is because of optical tricks that we do. These tricks make the show effective, while, at the same time, keeping the exposure level well below that of an ordinary 5mW laser.

An explanation of what is done is alluded to in the following two documents:
http://www.pangolin.com/resguide09a.htm
and
http://www.pangolin.com/resguide09b.htm

This has been public knowledge (on our web site and published in other written forms) literally for years, but hardly anyone really knows about, or practices the trick. Beyond what is written in those documents, what our system really does is make sure that the trick keeps working and that nothing goes wrong to disturb the trick.

What I am saying is...
Is it worth the risk?

Well, that's really the core question, and that is a question which each company will have to answer for itself.

Risk is an element of life. After all, getting out of bed involves an enormous amount of risk.

While researching the topic of audience scanning safety, we also looked into injuries from far more common things like telephones and sofas. You wouldn't believe how many THOUSANDS of emergency room visits are caused each year by fricken telephones...

From my perspective, Audience Scanning is a practice that has been performed outside of the USA for, what is now, the better part of 30 years, with relatively few injuries discovered, and those that have been discovered were caused by stupid practices of basically using inappropriate equipment (no scan-fail safeguards, pulsed lasers, poor projector mounting techniques, etc.). Also, as you noted in an early post, Audience Scanning is being done within the USA for years, mostly "underground" in raves and such, and being performed by laserists who know nothing about audience scanning or laser safety. And -- as John Tyrer (prominent laser safety professional) said in a previous International Laser Safety Conference presentation -- where are the body bags?

Basically, if we look at emergency room statistics, we can glean the fact that Audience Scanning, even when done incorrectly by people who know little or nothing about it, certainly appears to be safer than operating a telephone or sitting on a sofa <half joking here>.

Best regards,

William Benner

PS: Skipp, you appear to be the kind of person to try to rebut each and every point from someone who disagrees with you. I suggest that before you make your next post, you gather your facts and also be prepared to present the name of your buddy as well as all of the papers he has written on the topic of laser safety. While I certainly don't mind healthy debate, I will not participate in a discussion that does not present facts and other high quality and highly-qualified information.

[buffo]

Your statement here proves my statement true. You can take a higher dose of non coherent light than you can coherent light.

That wasn't your statement. Your statement was "any laser light entering the eye does SOME permanent damage no matter what", and that was the point I was refuting.

Most everyone here already knows about the diffraction limit and the dangers of coherent light. (It's covered in the very first section of the laser FAQ, and for good reason.) Not that it doesn't bear repeating, mind you - just that no one is disagreeing with you on that point.

It's your continued insistence that all laser energy, no matter how dim, is harmful and causes cumulative damage to the eye that is the problem.

Now before you get all hoity toity on me. Know that I have done thousands of shows.

I don't think quoting sources is out of place here. And despite your experience or the experience of your friends, that does not mean you are more qualified to judge eye injuries that an expert in the field, such as an opthamologist (or an engineer at the CDRH for that matter).

My first laser eye injury was caused by an audience scanning unsafe laser guy.

Again, I'm sorry this happened. But your status as a victim does not make you an expert. It's at best an anecdotal story that you are trying to use to support your claims of knowledge on the subject. For example, if I smash my finger with a hammer, does that make me a carpenter?

My second and most severe laser injury was self induced. The 20 watt laser I was working on was at waist level on a big cart.
It was at full power as I was cleaning and aligning it.

The fact that you were willing to align a 20 watt laser operating at full power WITHOUT GOGGLES makes me seriously question your "expert" status. Goggles are such a basic element of laser safety that it shocks me that you would consider working on such a laser without them.

The "tadpole" is not in my central field of view. <snip> It kinda swims around up there. <snip> Amazingly I still have 20/20 vision in that eye.

Then you did not burn your retina. Retinal burns do not move around. They're fixed in place in the field of vision. If you have a "tadpole" (ie floater), that *can* be the result of laser exposure, but if you have perfect vision in the area of the strike, then you did not permanently damage the retina. What did your opthamologist say about the injury? (Did you go to see one after the injury?)

This statement has a thread of truth. That thread is "light is focused to a very small spot". This is true it is focused into a very small spot on the portion of your retina that corresponds to the relative placement of the light source in space.

Which is a far cry from you statement that the light gets spread out all across the retina. I stand by my original statement.

As to the rest of the points of your post, in particular your comments about the FDA, I'll address them in my next post below.

Adam

[buffo]

Here is a little quote from that sight saying it took months to recover from a 5mW pointer injury.

The problem I have with that particular injury is that it's anecdotal. The laser exposure did not occur in a controlled environment, and the author of the report was relying on the testimony of the patients as to the accuracy of both the power level of the laser *and* the duration of the exposure. Since we all know that there are "5 mw" DPSS green pointers out there that both produce far more than 5 mw of visible output and also leak significant levels of IR, the power level claim of the laser is immediately suspect. (It wasn't measured.) Likewise, the duration of the exposure wasn't measured. The 19 year old patient essentially stared at the beam, intentionally fighting her blink reflex, noticed a problem with her eye later, and went to the doctor to complain. When asked how long she stared at the beam, she offered the answer of 10 seconds.

Also - just for the record, the study we're talking about was *NOT* part of Dr. Robert's work at the Mayo Clinic, it was a link in the works cited section to a report by Dr Zamir at the Department of Ophthalmology, Hadassah University Hospital, in Jerusalem, Israel. As such, this isn't a research study, but rather a report from a practicing physician on a patient that went to a hospital. There's a *huge* difference between anecdotal reports about patient treatment and actual, controlled research in a clinical environment.

I have seen more than a few people very high on drugs at almost ALL of the shows I have produced.
The drugs have obviously dialated their pupils to 8mm or so.
I ASSUME due to the dialation more light will enter the retina increasing the dose size.

You assume? Surely you are being facetious here. Of course more light will enter the eye. But CDRH variances already require you to use the worst case scenario for pupil diameter. In fact, in some cases (stadium shows, large outdoor venues) where it is possible that audience members might bring binoculars to enhance their view of the show on stage, the CDRH mandates that you use the larger diameter of a pair of standard opera glasses as your pupil diameter.

This I pulled from the ilda sight here http://www.laserist.org/Laserist/Safety_6.html

Those MPE levels are for shows outside of the UK. At the time the above document was created (1999), the CDRH had not yet issued a variance to *any* laser show company here in the US that allowed for audience scanning. Adhering to the requirements of that document alone would *not* be sufficient to perform a legal audience-scanning show here.

(from the ILDA Document) In summary, the MPE is a worst-case "safety factor". Exposure at the MPE level is already somewhat hazardous (statistically 3 out of 100 eyes would show signs of visible damage.) So additional factors such as a moving beam are assumed to further reduce the risk.

Those "additional factors" are the key portions of the Pangolin Audience Scanning Variance that you are leaving out of the discussion. And they involve much more than simply "moving the beam around".

All the quote above says is that, even in the event of a total failure of all your protection devices, sending a static beam out into the audience at the MPE level can be expected to cause, at worst, some signs of visible damage in 3 out of 100 eyes. It does not say those injuries are permanent, and indeed the changes may not even be detectable to the patron. (But would be visible upon a detailed inspection of the retina.) What is not immediately apparent from the article is that the vast body of clinical evidence suggests that these visible changes will heal completely with time.

And remember, we're not advocating sending a static beam into the audience anyway. And we're forgetting about all the other safety features that are designed to prevent this exact event from ever occurring.

So according to this IF I did a audience scanning show at MPE for an audience of 10,000 THAN 300 of those people would show signs of visible damage.

No. If you sent a static beam into the audience at the MPE level, you could expect to see visible changes in those people's eyes. That's not the same as performing a varianced audience scanning show using the Pangolin technology.

This states that the safety limits are all based on the blink reflex of 0.2 second.
So IF you do not blink these limits will be exceeded.

No. First, the limit above references the Class 3A limit for pointers; it's not related to the ILDA document we were just discussing. Also, you are consistently forgetting about other parts of a successful audience scanning system in your examples. It would be correct to say that "if you do not blink, *AND* the beam is stationary, then you will exceed the limit." But the beam is not stationary. (Pangolin's audience scanning variance does not rely solely on the human blink reflex. In fact, I'm not even sure it relies on it at all.)

Furthermore, remember that the limit is set at 10&#37; of the level where the majority of subjects would have some visible change to their retina. So you need to exceed it by a significant margin (an order of magnitude) before you have significant visible changes, and even at that level, 1) the changes are not permanent, and 2) there is no indication that the subject will be aware of those changes.

I mentioned the CDRH's class 3A limit only to put some perspective on the issue. If pointers can be sold to the general public at this power level, there must be some pretty hefty documentation of the effects on the retina at this level. (And indeed, there is.) The fact that you are claiming that this documentation is all wrong, and that all laser energy is harmful, is the thrust of this entire debate.

It is of my opinion that audience members will not continually blink when scanned with a laser. I also think the tendency to resist blinking in order to observe the laser effects increases the higher the audience member is on illicit drugs.

And if a variance only relied on the human blink reflex for protection, you would have a point. Since the variance we're talking about goes far beyond that, the blink reflex (or the state of intoxication) of the patrons is irrelevant.

Right the FDA.
They approved ALL of the following drugs too.

The examples you provided are lousy. Fen-Phen was not tested as a long-term diet aid combination. When it was discovered that doctors were prescribing it "off label", and heart valve damage was the result, the FDA pulled the drug as a precaution. Had the drugs been prescribed individually (rather than in combination), for short periods of time only (like they had been tested for and like the manufacturer recommended them for), the damage would not have occurred.

Vioxx was voluntarily recalled just 5 years after it was introduced by the manufacturer (Merck), after it was revealed that the initial report submitted to the FDA to substantiate the drug's safety contained deliberate errors and falsifications, and that other date had been withheld from the report. And what was the issue about? The famed VIGOR study, which found that the risk of heart attack in patients on Vioxx was .4% while only .1% for patients on naproxin. Whoop-de-do. Eating french fries at McDonald's will increase your risk of a heart attack by a lot more than that, yet no one is suggesting that they take fries off the menu. The issue with Vioxx was the cover-up, not the underlying risk.

Rezulin is actually a success story, not a failure. It was known to have higher liver toxicity, but was kept on the market because some diabetics responded better to it than other drugs. After 2 years of study, however, the FDA decided to pull the drug because they felt that the increased risk due to liver toxicity outweighed the benefits of treating diabetes without resorting to insulin therapy.

You want to talk about a screw up? Ok - I'll give you that Thalidomide was a disaster. But that happened in the late 1950's. We've come a long way since then.

These guys spent Billions on their PHD's who said their drugs were safe.

Wrong. Really wrong. Do you even understand how the FDA's approval process works? The FDA doesn't spend the billions. The drug companies do. The drug companies do the research. The FDA reviews the research afterwards, and decides if the body of evidence (previous research) is enough to justify putting the drug on the market. Essentially, to get a drug approved, you have to publish several peer-reviewed clinical trials that support your claim. Then those trials are reviewed by the entire medical community. And finally, the FDA does a final review before deciding to approve the drug, order more research, or reject it outright.

I think if you are scanning the audience you are blasting retinas period. If I am scanning a wall I am blasting said wall same difference.
I NEVER called Bill Benner "reckless".

No, you said that HE was blasting retinas. And blasting retinas is reckless. It doesn't matter if you think all audience scanning = blasting retinas. Without some proof that Bill is being unsafe you have no place accusing him.

I have seen very large projectiles flying through the air at several events. <snip> I assume a large projectile might dislodge or ever break Bill's lens from his projector. How would that effect the exposure levels?

You assume a lot. Be reasonable here; if a half-full can of coke thrown at a projector could knock the lens loose, do you really think the projector could survive the trip to the venue in the first place? Seriously, the lens is quite large, very heavy, and is actually part of the projector housing. To dislodge it would require enough force that I'd say the entire projector housing would fail at the same time.

Furthermore, how would the exposure levels be affected at your show if a "large projectile" dislodged one of your bounce mirrors?

I am sure Bill did all of his home work.

This is the first time you've said anything to that effect. Up to this point you were willing to dismiss him without a moments thought.

To say that audience scanning when done right is risk free is simply untrue. A truer statement would be, Audience scanning when done right is "safer".

At what point does "safer" become "Safe enough"? Do you own a car? Do you eat french fries? Do you drink alcohol? Do you have unprotected sex? Do you jump out of a plane? (Oh wait - yeah, you do don't you?) This is really starting to sound absurd...

OK - based on your line of thinking, I contend that your 20 watt lasers are a significant risk, even though you don't shine them at the crowd. What if an audience member throws a reflective surface into the beam? What if the mount on one of the truss-mounted projectors fails and it swings out of position? What if the mirror falls off the scanner shaft and lodges in position. What if the cover falls off the projector and the waste beam from the PCAOM gets out. What if, what if, what if... Life is all about managing risk, and there is no such thing as a no-risk activity. (Or to put it another way, life is a sexually transmitted, terminal disease.)

I find it incredibly hypocritical that you cite the dangers of bungee jumping as if they're incredibly serious (which, while the hazards do exist, they pale in comparison to an every day activity like driving), yet you gloss over the fact that people die from sky diving. And while you won't trust the government to regulate safety when it comes to lasers (the CDRH), you will trust them with your own life when sky diving (the FAA).

Don't get me wrong, I don't think sky diving is reckless... But it does carry *significant* risk. Risk far and away greater than laser shows. Yet you still sky dive...

What I am saying is even if it is "done right" in a safe(r) manor, there will be accidents.

There will always be accidents. You can perform a perfectly safe laser show and some drunk in the crowd will still manage to climb up the scaffolding, fall off, and break his arm when he lands.

Somebody will lose a eyeball.

No. The worst that would happen is that someone would have changes to his retina that could be detected by an opthamologist. No one is talking about "loosing an eyeball". In fact, you've admitted that even after taking a direct hit from a 20 watt laser, you still have 20/20 vision in that eye. So who's loosing an eyeball here?

I am not fearmongering I am looking at this with a little common sense.

No, you are fear mongering. You are taking the evidence of visible changes to the retina and equating that with "Loosing an eyeball". You claim to distrust the government, yet you rely on FAA regulation of another sport you participate in regularly. You propose several wildly improbably failure scenarios as if they're commonplace. That's not common sense, that's fear mongering.

Adam

PS: This is the first time I've run into the 15,000 character limit for a post. Whew! I think that qualifies as some sort of record...

[dave]

Interesting stuff! Keep the replies coming, interesting reading

[gottaluvlasers]

buffo, uv99, pangolin and DSLi-

all of you guys are HIGHLY respected and obviously know what youre talking about. my apologies if i started (with this topic) some sort of heated debate and got users here "blasting" each other. that was not my intentions WHAT SO EVER.

the replies, evidence, educated responses and detailed knowledgeable arguments are ALL (in my opinion) valid to some extent.

i dont think (again, i am IN NO WAY A PRO like any of you) that one person and their claims and their sources of of their knowledge should be discredited. whether its bill form pango, or UV99 (sorry uv- dont know your name. lol) you all obvioiusly know your shit. you ALL obviously have had personal and thought provoking encounters with various aspects of this whole "audience scan" topic. and you all have QUITE OBVIOUSLY done some sort of education wheter its through yourselvs, colleaugues, engineers or what have you.

80% of the information that has been brough to light here (pardon the pun) has been EXTREMELY educational to me. and im sure A LOT of the other people reading it. i just dont want to see valued and respected members here at each others throats.

i think the educational value and the safety value of this post speaks for itself especially when it is so well supported (to some extent) on BOTH sides of the debate.

i guess what im trying to say is sorry if i caused some sort of a members feud here. my intentions were NOT to try and discredit ANYONE or PROVE anyone wrong.

-Marc

[UV99LASER]

Hey I did not even know Bill's name until JimBo mentioned him by name.
I do not know Bill nor was it ever my intention to even to talk about him or his company.
I have no beefs or issues with Bill nor do I wish to.
I am stating my opinion interspersed with some facts.
Blame JimBo for dragging Bill from "pango" into this.

It is my opinion that Audience scanning is retina blasting.
Pure and simple you are terminating your laser onto someones retina.
It will be bright.

I have no beefs or issues with Buffo nor do I wish to.
With that said.

Buffo said
"The fact that you were willing to align a 20 watt laser operating at full power WITHOUT GOGGLES makes me seriously question your "expert" status. Goggles are such a basic element of laser safety that it shocks me that you would consider working on such a laser without them."

1. I never called myself "Expert" but thanks for the complement.
2. The beam came up under my safety glasses.
3. With safety glasses you can not see the beam. This leads to burning injuries.
4. Safety goggles for a whitelight laser? Would they be black? Could you see?
5. Brian from Cambridge Laser Laboratories works on high power ion lasers all day long with out safety glasses.
Brian IS an expert.

Buffo Said
"Furthermore, how would the exposure levels be affected at your show if a "large projectile" dislodged one of your bounce mirrors?"

I quit using bounce mirrors 10 years ago for that very reason.
I also only floor support my systems to prevent unintended projector re orientation.
All my projectors use hard lower apertures made from aluminum.
My rule of thumb has always been zero human laser contact.


Buffo said
"Then you did not burn your retina. Retinal burns do not move around. They're fixed in place in the field of vision. If you have a "tadpole" (ie floater), that *can* be the result of laser exposure, but if you have perfect vision in the area of the strike, then you did not permanently damage the retina. What did your opthamologist say about the injury? (Did you go to see one after the injury?)"

I saw doctor and I have a photo somewhere of the retinal burn.
No the spot does not move around. It is in the upper portion of my field of view. If I turn my head the dark spot will move across white walls. Thus giving the appearance of movement in my upper peripheral vision.
Brian from Cambridge says the hole in his eye is blue.
The doctor said he had never seen an injury like mine.
He called it permanent retinal scaring.

Most people who suffer a retinal injury will most likely never know. Unless the injury is so sever there is no ignoring it.
I believe this would explain the lack of emergency room statistics.

Again

IF everything works as calculated...
IF the electronics do not fail...
IF the diffusing lens stays in place....
IF the MPE levels are not met or exceeded....
IF the audiences pupils do not exceed 6mm dialation.
IF the show does not have to happen in the real world..
And IF al \the other IFs work as planned
Then I would say audience scanning would be safe.

Those are a lot of ifs.

I have seen a lot of large well established laser light companies doing public shows with out a basic lower limit aperture. I am sure you all have too.

We all have seen the best laid plans go horribly wrong.
I have serious reservations about trusting my eyesight to any laserist no matter how qualified.

I will ask the VISIX engineer if I can post his name. In fact I will forward him this thread. He is much more qualified than me. I hope he will post on this thread.

My point is audience scanning is NOT risk free.
I do not think you can argue with that statement.

And while a audience scanning show "done right" by someone like Bill might mitigate the risks to a reduced level. I do not think the risks are eliminated.

Furthermore it is my opinion that the bulk of people doing audience scanning will not have Bills level of expertise, safety or attention to detail required to "do it right".

And yes I have used the big red mushroom button due to "audience unruliness".

I am speaking from my real world experience.
What I am saying when it comes to audience scanning is CAUTION.
Old adages are old adages for a reason like it is better to be safe than sorry.

Skipp

[JimBo]

Hey I did not even know Bill's name until JimBo mentioned him by name.
I do not know Bill nor was it ever my intention to even to talk about him or his company.
I have no beefs or issues with Bill nor do I wish to.
I am stating my opinion interspersed with some facts.
Blame JimBo for dragging Bill from "pango" into this.

Proof of this is the varience that Bill from Pango has acheived.

That isn't exactly dragging Bill into it, it was a reference to back up my claims that it CAN be safe and without injury.

I also only floor support my systems to prevent unintended projector re orientation.

Can you just clarify that a little?
If the projector is on the floor where do you project the image? Surely by the nature of the beam it could only be projected onto the ceiling, if it is projected onto anything else there would need to be a massive distance between the projector and the audience to have the beam safetly 3m above the audience.

You are taking a sidestep now though, your original comment was that lasers entering the eye is ALWAYS harmful.

Jim

[UV99LASER]

"Floor support" such as tripod or truss support with hard mounting points such as bolts or ratchet straps at the least. I always put the projector at the minimum federally required height so that the lowest beam point is no lower than 3 meters or 9'6".
I do not hang or install projectors in any way as to allow movement by foot traffic or induced swing. So putting a projector on the floor is out.

I only mentioned you JimBo because Bill said he replied because he was mentioned by name. Prior tho this thread I did not even know Bill's name. I have heard it in passing in several conversations.
I am not a Pangolin guy I own five X-29 and X29-2 systems.
One day I will have a Pangolin it is inevitable resistance is futile.
Skipp

[JimBo]

One day I will have a Pangolin it is inevitable resistance is futile.
Skipp

No arguments with that one

Jim

[Pitts]

I'm with Dave... this thread is a most informative read.
Maybe as humans we sit up and take more notice (and learn more ?) when it gets a bit "soap opera" like. Drama is always attention grabbing.

The good thing here is that people that know their stuff are laying it out.
We can all learn from this.

What I would like to comment on though is that the subject of audience scanning is one to be taken very seriously indeed. I have started to study the various papers and information available (and there is quite a bit if you look for it)
[ Try Pangolin, ILDA, etc etc]

For me there is no way its going to happen until I understand all of the issues and implications. Knowledge is power. (and safety)

Careless and stupid actions can only result in more attention from the Feds no matter what country you live in and that cant be good for any laser operator or company. Feds love to make rules and regulations its in their nature.

Cheers

Ray
NZ