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Thread: Facebook Discussion on Laser Safety...

  1. #1
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    Default Facebook Discussion on Laser Safety...

    Hi all

    I have just been involved in a discussion on Facebook (probably not a good thing i know ). This was on a DJ forum that I tend to frequent from time to time, I post below the transcript of the conversation for interest. I have changed the names (except mine) to preserve anonymity, note that 'DJ' is short for a DJ . I am not posting this to make fun of or belittle anyone, I merely post it to show that we have a lot of work to do to educate people. i'm trying to do my bit in that regard, are you?...

    Oh, and sorry about the naff formatting. Cutting and pasting from FB doesn't appear to be straightforward.



    
As a DJ I have never had lazers but a year back I invested in a small one. I want to use them but unsure on risk so for those of you in the know can you advise ��
    Like 4 hours ago

    


DJ… Theyre pretty safe today mate.


    SN… i have a small one and love it I aim it at the ceiling to be sure it doesn't get anyone in the eyes

    


CS… I just concerned on those that suffer fits etc. Personally they look ace

    DJ… Lazers wont cause a problem generally with photo sensitivity. As for eye damage, its the wrong part of the spectrum to do anything of substance. Youd need to he staring directly at the beam for a good few minutes to sustain any injury. So unless its a static one you'll be fine.


    CS… Arh ok so whats a good one that impresses but compact

    


DJ… Depends what you want to spend. As much as I hate their stuff KAM do seem to be the top seller


    


Jem… Keep the beams well above the audience and there's no problem. Ensure no beams can be bounced back into the audience from reflective items such a light fittings etc.
    If you want to shine beams into the audience (audience scanning) you must be able to work out maximum permissible exposure to ensure the beams are eye safe.


    CS… Would like to add one to my main set and use on weddings so somthing that wows both. Not sure on cost but not an issue as company expense lol ��


    Jem… DJ… you're information is incorrect. Lasers can and will cause eye damage, even if only exposed momentarily if the power is above safe limits. This applies to pretty much All lasers including those in the visible spectrum.


    RS… hi CS…, from a dj and also an epilepsy sufferer, I don't use lasers myself but I have been in venues who have them, I personally have not had fits from them although I have had to have a couple switched off cos I was getting pre fit warning, but my partner has ended up having fits 3 times because of lasers, but that was only when the lasers were being aimed at eye level, when aimed on ceiling or walls no problems hope that helps

    



CS… Thanks some great post there. Admin gonna ban me soon as I put too many post on here ��������

    JD… In America. Anything above 4.5 mw then u require a license. But in the UK it doesn't matter at all


    DJ… jem im not incorrect. its the wrong wavelength to cause the problems youre thinking of. youd need some serious power to inflict it at that band.


    Jem… JD… it does matter in the UK. Might be worth reading the HSG95 document for a start.
    Http://www.hse.gov.uk/pubns/books/hsg95.htm
    DJ… you are wrong on so many levels. You have been seriously misinformed and the information you believe to be correct is down right dangerous.
    
The radiation safety of lasers used for display purposes - HSG95 
www.hse.gov.ukFor employers and employees using lasers in entertainment, theatre and public exhibition work; also for equipment suppiers.






    CS… Lazers cost from 50 to a 1000 but buying the cheap ones there must be dangers here esp with the lower end. This is wat im trying to find out really...

    I guess the higher end could be dangerous too depending on how pwerful it is

    



DJ… i work with lasers on a daily basis covering multiple bandwidths and power levels, you sure you want to get into this?.

    


CS… Chillax guys ..... ��

    
Jem… Please, please, please guys. Read the HSG95 document I've linked to.
    Pay particular attention to Chapter 1 on laser hazards, see item 18.
    There is so much Mis information out there.
    All DJ's should read this document before using lasers.
4 hours ago Like

    


Jem… DJ… this is nothing personal. I know what I'm talking about and it would serve you well to become familiar with the contents of HSG95 as a starter.


    



DJ… indeed they should, but it would be more informative if the document contained the frequencies they are concerned about. modern disco lasers are too low to cause eye injury unless you are deliberately staring into them directly for several minutes or you manage to get more than about 200 watts out of them.

    


DJ… im very familiar with it.. i work with lasers.

    


JD… Ok lol. I was wrong. I guess it do matter. But I will say its like anything. Common sense.





    Jem…Wrong, wrong and wrong again. Please, read the document.
    I don't care whether or not you work with lasers. You are just wrong.


    Jem… DJ… please see Chapter 1, item 15. This gives details of visible wavelengths.


    Jem… Also note the keypoints in Chapter 1. I quote..."Display laser installations that use lasers with radiant powers greater than 5 Milliwatts are capable of damaging a persons sight if viewing is uncontrolled".


    



DJ… Out dated. We no longer use ruby and emerald exciters in their construction. Thats why they dont harm at lower spectrum ends. (Call it a cleaner radience if you like). And at best thats an abiguous statement which in standard h&s fashion errs very far on the side of caution.


    



DJ… Simple rule of thumb. If you can lift it on your own its not going to have enough power to hurt you..


    DJ… But I'll give you your dues. At least you arent arguing a dangerous point. Thats a very refreshing change in these forums 


    Jem… Sorry DJ… but you are sooooo wrong. I really think you need to attend a refresher course on laser safety.
    Your statement above relating to "if you can lift it on your own it's not going to have enough power to hurt you" is utterly ridiculous. Have you seen some of the latest projectors... 20+watts in the size of a shoebox!... And it doesn't need three phase!


    DJ… At what wavelength?

    Jem... RGB. Visible wavelengths between 400 and 700nm. Quite often using Coherent Taipan lasers. These days you can easily exceed 10 watts in a very small box using a mix of diode and DPSS lasers. Green still tends to be 532nm DPSS. However, new diodes are being released at 520nm and these will be a game changer, as were the 445nm diodes. A single 445nm diode has now broken the 2 watt threshold!


    


CS… ���������� to advance for me im outa here 


    



DJ… So we're still in nanometrics. Too low. Erring on the side of caution is fine. It will certainly keep you out of danger. But physics alone dictates that those wavelengths are too wide for rapid absorption without sustained high power. While they are not 100% safe (which I get the impression you think ive implied) accidental damage is not likely, you would still need to stare into the beam quite directly to come to any lasting harm.


    


Jem… Sorry, you're still wrong. Accidental damage IS likely from visible wavelength lasers.
    Let's try another route... http://www.nature.com/.../ncurrent/f...e2013315a.html.
    Sorry CS, but it's important that people realise that there is a real danger from shining lasers directly at people. I apologise to you directly for invading your thread.
    I will now bow out gracefully as it's quite clear that there are people here who don't wish to hear the harsh reality.
    DJ, I'm happy to continue this conversation by messaging if you so desire ��.

    
Eye - /`Toy/' laser macular burns in children 
www.nature.comEye is the official journal of the Royal College of Ophthalmologists. It aims to...See more





    DJ… Its no good blanket approaching all wavelengths. Be specific.

    Jem… Have you read the article I just posted? I think it's made pretty clear in there.
    However, let me turn your post around... Which wavelength(s) do you think aren't dangerous?


    DJ… I havent said any "arent dangerous". I'm simply pointing out that the level of risk from what you get in mobile disco laser units is overstated. The danger is there and is real. It just isnt as big as the H&S safety documents will imply...


    


Jem… Ahh... Now we're getting somewhere and it's nice to see you accept that the danger is there and is real.
    One step at a time, one step at a time...

    CS… �� and calmer returns

    
DJ… Think you've probably over read what im saying.

    



Jem… Err... No, I don't think I've over read it at all. Re-read this thread from the beginning and take note of some of your outrageous statements in the early dialogue.
    Anyway, I'm delighted that you've finally come around to appreciating my concerns. Well done to you I say

    



CS… Ding Ding round twoooooo


    



TD… DJ..., just take it that Jem has a fair idea what he is on about. Laser, any size or power are dangerous, ignorance will not save your sight. Jem is not trying to belittle you, but educate, trust me he has a lot of experiance with lasers.


    


DJ… Anyone got an egg?.

    CS ���������������� hows that ��


    



Jem…Lol, no worries DJ. If we ever meet I'll be happy to crack a beer with you and we can discuss the ins and outs of lasers till we're either too drunk or too tired ��
about an hour ago.
    Last edited by Jem; 02-07-2014 at 06:21.
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  2. #2
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    Sadly true, and unfortunately not just limited to DJ's.

    People who consider themselves professional lighting people exhibit similar levels of knowledge and mis-information.

    I think the big problem is that in some respects he is almost correct - a correctly scanning laser of moderate power IS quite safe. But we are not doing the calcs based on a properly scanning laser are we?

    We are doing them based on an intentionally or un-intentionally slow/static beam (the worst case scenario!) which so many people seem happy to disregard.
    http://www.facebook.com/SubsonicSystems
    http://www.frikkinlazors.co.uk

    You are using Bonetti's defense against me, ah?

    I thought it fitting, considering the rocky terrain.

  3. #3

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    Jem I vote you post fb group details and send the boys in
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  4. #4
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    That is scary, what some people think. Especially the part
    "if you can lift it on your own it's not going to have enough power to hurt you"
    .. wow.. and
    "modern disco lasers are too low to cause eye injury unless you are deliberately staring into them directly for several minutes or you manage to get more than about 200 watts out of them."
    200 WATTS ??? Really ??? DJ dude is clueless. Geez ..

  5. #5
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    wow this dj sure is as well informed as an 5 year old is on nuclear fusion. (aka not).
    Where do people like him find this information.

  6. #6
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    Give him a 2W laser pointer to play with. He will very rapidly become unable to blind punters with lasers

  7. #7
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    Keep an eye on this guy, as someday he just might be a candidate for a Darwin Award.

  8. #8
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    Brilliant! Although I think his knowledge (or complete lack of it) is limited to Maplin, Jaycar, Radio Shack or whatever 'toy' store style shops are local to you!

    Perhaps invite him to a local LEM for testing?

  9. #9
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    Where do people like him find this information.
    Probably from the muppet sales person he bought it from

    Give him a 2W laser pointer to play with. He will very rapidly become unable to blind punters with lasers
    I'm with you on that, I would have suggested he tested his theory with that 200W laser he has access to
    RTI Piko RGB 4 Projector
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  10. #10
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    I felt like reaching through my screen to strangle DJ, reading that... I feel very sorry for the public exposed to his shows....

    Anyone know the best way to melt lead? I feel the need to lead pot my projectors so they require a 2 man lift. Only then will we know they are not safe.
    This space for rent.

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