Yet another Newie looking for Laser Advice

[Stiffler]

One last (I hope) bit of advice, what is the best way to work out the configuration of each colour the laser? Take the Pluto II RGB4000, this is 1000R, 1000G, 2000B, why is there such a different between the R+G and the B?
I have worked out that is has to do with the aperture size and how is combines the beams but how do you work it out what to buy?



Brian

There is no standard for white balance, and everyone does it different. The human eye is most sensitive to wavelengths around 555 nm (green), and least sensitive to blue when there is ambient light present (in the dark the human eye becomes more sensitive to blue light), so if you want the 3 colors to appear equal in brightness you typically want more red & blue. Personally I think the red should be the most powerful of the 3, especially for beam shows as the longer wavelengths scatter less. All that being said, blue is the cheapest so that's why they are using so much of it.

-Eric

[Bradfo69]

Here is a good example of "perception"



On the left is a Kvant Spectrum 1.6 watt, ( I "think" 800mW blue, 500mW red and 300wm green) the one on the right is a Pluto II 2.5 watt (1 green, 1 blue, 500mw red) Pluto looks pretty good right?

Now:



The one on the left is a 3 watt (1.2 of 640 red, 900mW blue and 800mW green) and the Pluto is still on the right. Pluto doesn't look so good right?

To look at any of these on their own - they'd look "white". Both projectors were a lot more money than the Pluto.

[norty303]

Here is a graphical demonstration why there is a power mismatch between colours, and it concerns the human eye's sensitivity to certain wavelengths of light.



Green is right up the top of the sensitivity scale, so we need less of it, whilst red and blue at the far ends of the visible spectrum need a lot more of them to be perceived as the same brightness as the green

This is similar to the way we hear low frequencies, requiring a lot more power in the sub region to presetn a balanced sound, and relatively tiny amounts of high frequency content.

[UKEventLighting]

Once again you guys are a fountain of knowledge

Speed during an emergency situation is critical. Slamming that big red button is quicker than hitting the power switch or stopping the output via software. That last option wouldn't address several dangerous situations, of course, so don't depend on software alone for saving anybody's eyes. Also note that you should never leave the projector in a situation where plugging it back in is enough for it to resume output as someone else could plug it back in without your supervision.

Sorry I should have made that a bit clearer, there will be a BIG red button to slam (big buttons are always good), but this will kill the power to the laser, no power, no problem.

The questions, lets say I’m doing an event, I run the laser for 30mins, then have a break, I would tell the software to blackout and then hit the big red button, this kills the power to the laser and I walk off with the key so nobody can turn it back on.
What the question is when I come back, put the key restoring the power the laser will go through a power up cycle, what does the laser do during the power up apart from resetting mirrors etc, at any point would it allow a single beam out or just stay in standby until the software tells it to do something? Second to that, is this going to damage the laser by killing the power?
Found this video that talk about just this, it says that the QuickShow powers up in safe mode, trouble is it was connected to the PC???

http://www.youtube.com/watch?v=pohPy...7Dsv2w&index=4

Physical barriers securely affixed to the projector allows you to block unwanted beams on the sides and above (think balconies). A lens like Safetyscan lenses are half circles and therefor more appropriate for diverging beams below a certain level as opposed to blocking them altogether.

I have just watched a SafetyScan lens video on YouTube, http://www.youtube.com/watch?v=ooZ1C...1cS7PHgs7Dsv2w
This is great so scanning, no good for graphics, are you saying you can buy a unit that fixes to the front with barriers with thumb screws you can wind in blockers (like shutter blades on theatre spots), if not I feel a visit to a local engineering company come on….
While watching the first video it talked about Beam attenuation, I have now found I have now found this, this was covered in the online tutorial, this also give me a lot more fleability.

I think I am going to order the a unit from Lightspace, these are the offers he has suggested within my budget, which would you have?



Pluto II RGB 2watt
Red638nm 500mw, G532nm 500mw, B445nm 1000mw, ILDA-30kpps, with Pangolin Quick Show package, 40k scanner extra $100

Pluto II RGB2.5watt
Red638nm 500mw, G532nm 1000mw, B445nm 1000mw, ILDA-40kpps, with Pangolin Quick Show package

Pluto II RGB2watt
Red637nm 480mw, G532nm 500mw, B445nm 1000mw, ILDA-40kpps, with Pangolin Quick Show package

Once again thanks for all your help guys

Brian

[norty303]

The questions, lets say I’m doing an event, I run the laser for 30mins, then have a break, I would tell the software to blackout and then hit the big red button, this kills the power to the laser and I walk off with the key so nobody can turn it back on.
What the question is when I come back, put the key restoring the power the laser will go through a power up cycle, what does the laser do during the power up apart from resetting mirrors etc, at any point would it allow a single beam out or just stay in standby until the software tells it to do something? Second to that, is this going to damage the laser by killing the power?

Depends on how you implement your estop to be honest. Killing power is not the best or quickest way to shut a laser projector off.
It can also mean that you actually create dangerous static beams because the scanners stop moving before the lasers stop lasing due to residual current in the supplies.

My safety boards have the keyswitch feeding one of the interlock circuits, as is the estop button feeding another. Unless all interlock loops are closed, the modulation for the lasers is disconnected. If you hit the stop, the lasers stop, but the scanners keep on running which is safest in my opinion.

The Safetyscan lens is fine for graphics, because you don't scan graphics down into the crowd generally, you scan them onto a screen/scrim/wall over the top of the crowd. The lens is only a half lens, so only the lower part of the scan window is affected.

[Bradfo69]

Hi Brian,

Based on what I know about Lightspace, I would go with the third option - the Pluto II RGB2watt. My main reason for that is the 637nm red versus the 638nm red in the first two. The beam characteristics on the 637 should be much better than the 638. Take the 637 red from the third projector and put it in the middle projector and that's what I, and a large number of others here have. If you want some pics, and good info, see this thread.

http://www.photonlexicon.com/forums/...ee-(Lightspace)

In answer to your question, when powered on, good projectors should just stand there and wait for instructions from the software. Cheap projectors are notorious for firing out a quick beam sometimes either on powering on or powering off. It's one of the big things here in the US that needs to be prevented to get a projector variance. It shouldn't hurt a projector to have power yanked off but, ideally you should try no to turn them on or off with a live signal going to them. Stop the signal, then turn off the power. It allows your galvos to get back to a home position and such.

[UKEventLighting]

Well I’ve only gone and done it…….. New toy on it’s way !!!