RGB laser, help please!!

[White-Light]

Thanks for all your threads they have been really healpfull. My main problem with the 445nm is that in some clubs the color used to look more purple than normal.

Exactly my view on 445, it swings the bias of many of the mixed colours into the purple end of the spectrum and pulls the luminosity down as well. 445 is towards the bottom end of the blue spectrum so a purple tinge is entirely possible depending on exactly what wavelength the diode is actually outputting - remember there is a frequency range, your diode is not guranteed to be exactly 445. Maybe your diode is varying slightly in wavelength towards the lower end of its stated range or maybe extraneous lighting from other lights is affecting the visible balance.

Something similar also happen with the 650nm red, in some darker clubs you can see it that well, but yesterday when i use it on a club that was painted White, and i was able to see more red power than ever

Nothing mysterious here. Anything shows up better against a white background than of course white itself.

This picture is using a 300mw 447nm CNI diode, it does look quite purple, the photo i toke it from about 80ft

http://img256.imageshack.us/img256/821/img0814vz.jpg

447nm (?) is at the lower end of the blue spectrum so some purple is to be expected.

To check the problem with the red you can check this video, the first video i toke it from about 50ft away, the second is from about 120ft away (Laser is 800mw 650nm, 500mw 445nm and 300mw 532nm)

http://www.youtube.com/watch?v=uPtZX1lQsks

I'm not sure what we're looking for here as it all looks pretty normal to me. 650nm is not the brightest of red as its a deep red. 640nm shows considerable brightness gains whilst maintaining a deeper appearance than 635 which has an orangy appearance. Hence the reason 640 is so popular - deep red but much brighter than 650. The beam specs also mean you eliminate any in projector loss.

Two things that do stand out from that video for me that need commenting on are:

1. You have a lot of competing lighting in the form of moving heads and LCD screens. Simply blacking out the other lighting (not the screens as some low lighting level also helps with safety), when the laser is on will result in significant visibility gains. It also gives you the opportunity to give your audience's eyes "cooling breaks" when the other lighting is on and the laser is off.

2. I'm a little concerned about your safety here whilst not wanting to divert the thread off topic. The laser is mounted low down and accessible and also very close to the front audience members for something of that power. I hope you're taking readings!

Any idea why this happens, or if i go with diodes like 640nm and 457nm this wont happen that often (my theory is that is more bright for my eyes in a controled situation this will also help in a regular day)

Thanks for your time

As above, 445 is close to the lower end of the blue spectrum. Going for a wavelength higher up will increase the blueness of the beam and its visibility. 457nm is often commented on as still a deep blue (I haven't seen it myself). 473nm is the brightest blue but is regarded my most as cyan rather than blue.

On the 640nm subject, you'll significantly increase visibility with 640nm over 650nm for any given power level. eg around 700mw 640 has the same luminosity as 1 watt of 650nm on paper. I'm sure some will report in their experience it appears even brighter than that.

[Insanity]

Hmm, seem to remember having this conversation many, many times in the past...

Here's what I know from real world experience:

Most of the big manufacturers like Kvant, Medialas, HB, RGB Laser Systems and so on are using 532nm, 640nm and 445nm in their pro level projectors.

HB are using equal measures of each wavelength and the real high end stuff is using OPS Lasers at 530nm, 630nm and 460nm, and some with a 577nm line... I saw these lasers running and they all looked amazing.

Remember there is more to the visibility of lasers than just wavelength; beam diameter, divergence and modulation characteristics all come into play here. These lasers are being used because they are producing beams with similar characteristics...

The laser Whitelight is referring to at UKLEM was connected to a Pangolin board and the colour palette had not been tuned to the laser, which is why the colours were off. In one of the many other threads on this subject, Pelosh said he had not tuned the palette and he then uploaded a video of the laser with the palette tuned. But we all know you cannot judge a lasers real world colour from a video or photograph.

I have been using 445nm in my projector for 18 months now and I have no problems with it whatsoever.

The main critical thing is that you spend a serious amount of time tuning your colour palette. Do it in complete darkness and with a bit of ambient light. My projector is displaying colours that 'I' think are spot on, but of course another pair of eyes looking at those colours might see something completely different.

So, I would say go for 532, 445 and 640. You will have a nicely converged projector and if you spend time on your colour palette you will not be disappointed.

If you go out and spend thousands on a 457nm and you are not happy with it, you have lost thousands. If you are not happy with 445 you haven't lost much. Under show conditions I think you will be hard pushed to tell the difference and I doubt very much that your customers would either...

Mark

[Doc]

I'd have to agree about the colour palette. After installing 445 in my projector everything looked slightly purple, however once everything is adjusted to compensate it looks great. Try adding a little 532 to blue and it brightens it right up.

These are taken 150' back from the stage and though it is a darker colour and competing with realy bright led panels, who cares, just add another Watt or two!







These are taken from the stage





Of course that lovely purple is there if you want it

[norty303]

Remember there is more to the visibility of lasers than just wavelength; beam diameter, divergence and modulation characteristics all come into play here. These lasers are being used because they are producing beams with similar characteristics...

^^ This

I think power density is a key factor in relative brightness too, which is also why 640 seems to do so much more than it should, mW for mW

[p1t8ull]

The laser Whitelight is referring to at UKLEM was connected to a Pangolin board and the colour palette had not been tuned to the laser, which is why the colours were off

A perfectly reasonable explanation, but surely White-Light wouldn't form such a strong opinion on the use of 445nm lasers in RGB projectors and recommend more expensive alternatives based on only ever seeing one 445nm powered RGB that hadn't been palette tuned?

[White-Light]

@ Pitbul, I've seen a video that Martin posted of his Kvant afterwards fully tuned in response to my observations at the UK Lem that still didn't endeer me to the colour balance for the reasons I've stated. Like I said this isn't a go at Kvant lasers or Martin, they're fantastic gear, and he's a fantastic guy, its just I'm not keen on the way 445 seems to influence other colours in the mix on any 445 projector I've seen footage of.

This is the best comparison I can do off the top as I don't have Martin's video to hand (you probably need to watch both for quite some time as they both start off slowly):

Look at this Kvant display with 445nm especially from 1 min onwards: http://www.youtube.com/watch?gl=US&hl=uk&v=rKwW_EYvYqk

The compare to this Ministry display with 473: http://www.youtube.com/watch?v=uSmpGxIQcPk

OK so not a fair back to back comparison as I can't guarantee all the parameters are exactly the same. However, even in the relatively poor quality Ministry video (there's a much better one out there thats no longer on Youtube), the lighter colours to me have more punch in the presence of 473 in the mix instead of the 445 in the Kvant.

@Doc, I fully appreciate that adding some 532 into the 445nm might help alter the balance. After all you're effectively shifting the perceived wavelength upwards in much the same way that mixing red and green produces a wavelength thats perceived as yellow. I'd imagine adding a little green leakage into the 445 blue probably shifts it upwards to a preceived wavelength somewhere between 445 and 473 depending on the amount added.

[p1t8ull]

I'm trying really hard not to type what I'm thinking right now

[danielbriggs]

I'm trying really hard not to type what I'm thinking right now

I'll do it...

[Insanity]

@ Pitbul, I've seen a video that Martin posted of his Kvant afterwards fully tuned in response to my observations at the UK Lem that still didn't endeer me to the colour balance for the reasons I've stated. Like I said this isn't a go at Kvant lasers or Martin, they're fantastic gear, and he's a fantastic guy, its just I'm not keen on the way 445 seems to influence other colours in the mix on any 445 projector I've seen footage of.

This is the best comparison I can do off the top as I don't have Martin's video to hand (you probably need to watch both for quite some time as they both start off slowly):

Look at this Kvant display with 445nm especially from 1 min onwards: http://www.youtube.com/watch?gl=US&hl=uk&v=rKwW_EYvYqk

The compare to this Ministry display with 473: http://www.youtube.com/watch?v=uSmpGxIQcPk

OK so not a fair back to back comparison as I can't guarantee all the parameters are exactly the same. However, even in the relatively poor quality Ministry video (there's a much better one out there thats no longer on Youtube), the lighter colours to me have more punch in the presence of 473 in the mix instead of the 445 in the Kvant.

@Doc, I fully appreciate that adding some 532 into the 445nm might help alter the balance. After all you're effectively shifting the perceived wavelength upwards in much the same way that mixing red and green produces a wavelength thats perceived as yellow. I'd imagine adding a little green leakage into the 445 blue probably shifts it upwards to a preceived wavelength somewhere between 445 and 473 depending on the amount added.

How do you know that those lasers in either video are using 445, 473, 460, gas wavelengths or what? Remember Kvant make projectors with OPS Lasers as well...

How can you make any valid judgement based on two videos of two completely different systems filmed with different cameras in different settings?

You CANNOT make any kind of informed decision based on a video and when you are advising somebody to spend thousands on a piece of kit you have only seen on video, but can't be sure what you actually saw, how can you justify that?

Sorry but you are arguing with people that own 445nm projectors, have built 445nm modules and use these things on a regular basis, when you have only actually seen one badly tuned unit in the flesh and a whole bunch of videos.

I have videos of my lasers in the same venue on the same night taken with different cameras and the videos look completely different...

Mark

[White-Light]

I'm pretty sure at the time the Ministry video came out 445nm didn't exist and someone told me they were using 473 in there. In fact I was actually told the company that supposedly supplied them and I looked the lasers up on their site. I even went as far to email for the specs but never got a reply. I forget which company it was only that it was Eastern European from memory.

As for the Kvant video its fairly recent (2 years or so) and Kvant switched away from 473 several years ago to 445nm way before 445 diodes became available. The blue looks like 445 to me in several shots.

Like I said above, not perfect examples because of the variable but the best I can produce.

At the end of the day its for everyone to make their own minds up about 445, but personally I still don't rate it. Everything I've ever seen says to me that its a nice colour on its own but it pulls many of the other colours down in luminosity. If your beliefs are different then thats fair enough. What's not in dispute though is the fact that since Casio came on the scene, its by far the best value colour out there and if I was building I'd probably be forced by budget to use it. However, given the choice, I wouldn't.