Film-Tech Forum ARCHIVE: NC900c settings for max lumen output

This is topic NC900c settings for max lumen output in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Tom Wienholt (Member # 1510) on 01-12-2017, 04:08 PM:

How can the lumen output for an NC900c, or any other digital projector be maximized?

What color settings, etc. should be used?

Posted by Carsten Kurz (Member # 5396) on 01-12-2017, 05:08 PM:

You mean while maintaining DCI/SMPTE calibration specs, or neglecting them?

- Carsten

Posted by Stephan Shelley (Member # 8587) on 01-12-2017, 06:18 PM:

While keeping it in DCI specs you can use both lamps and turn them up to max. Beyond that you can remove the notch filter on the top. You will have to redo the color settings to get anything close to watchable. It will not meet DCI specs when you do this. You will get more light but color will not be so great. Make sure to install the dummy filter to fill the hole so dust and dirt do not get sucked into the projector. It comes with the projector.

Posted by Mike Babb (Member # 1379) on 01-12-2017, 07:51 PM:

film bleu instead of film noir

Posted by Mark Gulbrandsen (Member # 72) on 01-12-2017, 07:52 PM:

Even though the version 2 lamps are a little better then the originals, I really don't recommend running THOSE lamps at max wattage, ever. When I was installing these I tried to spec the systems for 85% maximum lamp current in scope to get some life out of the lamps. Run them at the top end like that and they'll go kaboom. NEC may not warrant them either, once they see the projector logs...

Mark

Posted by Marco Giustini (Member # 4544) on 01-13-2017, 03:19 AM:

why would they refuse to honour the warranty on NEC lamps on NEC machine running at a setting which is allowed by their own software???

Posted by Steve Guttag (Member # 268) on 01-13-2017, 06:17 AM:

Actually, as per NEC, for proper DCI color, one has to run them at a particular level (88%).

In truth, one needs to create MCGD settings for EACH level one wants to run the lamp(s) in order to maintain color.

The only way NEC will deny warranty is if you are running the projector out of its temperature range. This is why they want logs when you file for a warranty claim. If you ran the lamps hot (and you really have to ensure that the rear of the projector is not obstructed or it will suck in its own exhaust air).

You can't run with the notch filter out and the dummy not in, you'll have red tail lights (you've opened the optical path up). While you can color correct the primaries still, you'll never achieve a uniform color across the spectrum. The notch filter isn't there for the fun of it and the type of notch depends on the light source. Think of it as parametric EQ for light while your color correction is more like bass and treble shelving filters. You can nudge the end points around but you can't really do anything with the in between stuff.

Posted by Marco Giustini (Member # 4544) on 01-13-2017, 06:33 AM:

quote:
Actually, as per NEC, for proper DCI color, one has to run them at a particular level (88%).

and using both lamps, I understand.

Posted by Steve Guttag (Member # 268) on 01-13-2017, 09:34 AM:

Yes...both lamps are required (or you will not evenly illuminate your screen). My post above has a miss-type in that you CAN run with the notch out and the dummy in but you HAVE to put the dummy in to clear the red tail light alarm. Note, if you pull either the dummy or notch out while the projector is on, the lamps will go out immediately.

Posted by Tom Wienholt (Member # 1510) on 01-13-2017, 09:58 AM:

My understanding is that color correction reduced lumen output. So what settings will eliminate all color correction for the highest output?

Posted by Mark Gulbrandsen (Member # 72) on 01-13-2017, 11:39 AM:

That's true Steve, but you'd have to reset the colors on that machine literally about every other day to keep them constant. Theater owners only seem interested in how many hours they can get out of lamps... and IMHO, NEC made a big mistake by not going with the 450 watt version of these lamps in tis projector, or perhaps making the 350 and 450 work in the same machine. But it is what it is and the 900 has kept a lot of theaters from closing their doors permanently.

In my experience running these 350's at the top end right off the bat is almost sure to cause at least one to explode very prematurely, like within the first 30 or so hours. I have one that was put in on a 29 foot wide screen and those had to be run at the top end, it resulted in many, many blown lamps. The screen there was since replaced with a smaller gain screen and masked back to a size within the capability of the projector, and the lamps run a long time now. Most of the 900's that I installed are on 22' wide or smaller screens.

Mark

Posted by Steve Guttag (Member # 268) on 01-13-2017, 12:39 PM:

Oddly enough, I haven't found that the color drifts very much as the lamps age. Only if their power is varied. I do agree, run them as low as permitted for longer life. Temperature is their enemy.

Note, the NC1000 isn't 450W lamps but 400W lamps. I'm surprised they don't have an update kit for the NC900 since all that I think is different is the ballasts and lamps (the two things that like to fail a lot).

Posted by Mark Gulbrandsen (Member # 72) on 01-13-2017, 01:14 PM:

Exactly. I checked color on three machines that are close by and there was little change, just big changes in brightness. Bringing the light level back up then threw the colors slightly off again.

I agree on the larger lamps. Those would also have to be added to the lamp list in the firmware. They really need to do something so people aren't rnuning them at the top end all the time. There are lots of these 900's out there.

Mark

Posted by Steve Guttag (Member # 268) on 01-13-2017, 02:37 PM:

I fault the people that specified them. They were oversold for what they could do. With such BS as using 1.8 gain screens and ripping out the notch filter...etc. They are 4500 lumen machines, period.

NONE of the NC900s I put in were running anywhere near top of range.

I really wish NEC had a lamp alternating option such that it would strike the lamp with the least hours too.

I think people are going to be woefully upset that their laser-phosphor systems don't do so well later in life either. If you put in a system that is running at or near 100% when new will be down to 50% by 20,000 hours or so...which means that within 5 years, they will likely be below SMPTE specs with no choice but to change their laser. Conversely, if they were to size the projector for 1-size larger than needed when new...that laser would likely last the life of the projector...but people will undersell the projector because people want things cheap with no thought to longevity.

Posted by Mark Gulbrandsen (Member # 72) on 01-14-2017, 02:45 PM:

I think it's to early to tell what life span on the laser phosphor systems really is. I do know replacement laser cost for NEC 1201 is about 7K. You can buy a shit ton of 350 watt xenon lamps for that 7K dollars...

The NC-1201 is also way more power hungry than the NC-900 is by a factor of about 35%. Since they are still making the usual lineup of xenon projectors at present I see no reason to jump into laser yet unless a customer really wants it badly, or just wants to be first. By the time Series 2 projectors really need replacing they'll probably be beyond phosphor laser anyway.

Mark

Posted by Steve Guttag (Member # 268) on 01-14-2017, 07:21 PM:

The NC1100L is the literal laser version of the NC900 or NC1000. But just using manufacturer's rosey optimistic life expectancies, the math doesn't work...unless you go one size over. So yes, if you use a 1201 instead of the 900, then your life expectancy should be very long...again, stop using BS gain screens. You never hit SMPTE light uniformity with them if they are above 1.3 gain. Put in the proper screen and use the proper light and things will look...well...proper. That said, the S2K projectors will still have crap contrast ratios and the laser-phospher projectors do nothing to help that.

I suppose a saving grace of using a moderate gain screen on an S2K projector is to try and hide the crappy contrast in the light falloff.