Film-Tech Forum ARCHIVE: Xenon Bulbs for NEC NC2000C

This is topic Xenon Bulbs for NEC NC2000C in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Justin Hamaker (Member # 2165) on 09-25-2011, 09:29 PM:

Just curious to know what others are finding about bulb life and brightness for the NEC NC2000C projectors.

Our first two projectors, which both have MasterImage 3D, are currently using Ushio DXL-40SCN bulbs. The oldest projecoter (a little over 13 months) will need it's third bulb soon. The second projector which was installed at the end of June 2011 is still on it's first bulb. Both are running about about 95% for 3D and 85-90% for 2D.

All 8 of the projectors I installed in the last month are using Christie CXL-30SC bulbs running at about 85%. While none of these are running 3D, it was immediately noticeable how much brighter the picture is compared to the houses with the Ushio bulbs when those are also running 2D. Obviously it's far to soon to know how the Christies hold up over time.

In our 35mm projectors, we found we had much better performance from the Osram XBO 3k than the Christie 3K bulbs. I'm curious to see how this translates to the digital projectors.

Posted by Monte L Fullmer (Member # 2797) on 09-26-2011, 03:31 PM:

The Ushio is a digital bulb (why the "D" in front of the "XL") that has a shorter gap and more compressed xenon gas inside for starters than the other bulbs made for film use ... if that helps out some....

Posted by Gordon McLeod (Member # 33) on 09-26-2011, 03:43 PM:

Welcome to the digital world often a installation is done based on a specific lamps performance Always it seems the one that has the highest light output new so the sales pitch looks good) but then it does its usual digetal light loss at 300 or so hours and requires a massive boost in current and then it fails
Of the Serries 2 machines Barco has the highest output for light but again specd with d cinema lamps

Posted by Marcial Feliciano Ramos (Member # 1989) on 09-26-2011, 04:46 PM:

We use Phillips 3000-HEHS (1300 hrs) for 2D screens and Phillips XDC-4000N (700 hrs) for 3D screens on NEC's NC2000.

Posted by Steve Guttag (Member # 268) on 09-27-2011, 06:10 AM:

MUCH more information is required to draw any conclusions. Starting with, the screen sizes and gains.

The DXL-40SCN is more akin to a cinema lamp adapted to digital use. Its chief advantage is its life. Not many 4K lamps can go 1500 hours under warranty! However, its light output is VERY low for a 4K...about 11,900 Lumens in the NC2000. By going to the DXL-40SN2, you'll get a jump to 14,000 lumens for about the same price but only 1000-hours (more typical of a 4K lamp).

As for the Christie CXL-30SC...I have not made any tests of it in the NEC...my suspicion is that one is likely to only get 7000-9000 lumens, at the start from anybody's 3K lamp film lamp. The problem with film lamps, especially the Helios is that they have a much faster decay than the digitals. A film lamp looses 20% of its light in the first 100-hours. A digital lamp takes up to 300-hours before it hits that mark and it is a much longer decay. In the case of the NEC, they have a DXL-20SN3 that is a 9000-lumen lamp and has a warranty life of 2400-hours. That lamp will likely out perform, over its life any other 3K lamp you put in there and cost less/hour as well...including on electricity.

As for your power levels...something seems amiss. I've never found that 2D and 3D power levels to be anywhere near similar. it is possible, your tech kept them closer so the lamp didn't have to content with wide variances between 2D and 3D...once a lamp runs hard for 3D, it often has trouble when trying to run at lower current (hard striking and more flicker).

-Steve

Posted by Justin Hamaker (Member # 2165) on 09-27-2011, 08:37 AM:

Steve: I'm only going on visual assessment as I don't have a light meter.

Here's what I can tell you.
-7 screens all about 37' wide.
-4 screens using Ushio bulbs have silver screens for 3D
-3 screens using Christie bulbs have white screens
-The three non-3D screens are the newest installs.
Sorry, but I don't know the gain numbers for any of the screens.

It was immediately noticeable that the screens with the Christie 3K bulbs were brighter at a lower power setting than the screens with the Ushio 4K bulbs (when they were running 2D).

The Christie bulbs are all within their first 100 hours while the Ushios are all probably 500+. But the difference is the main reason I posed this question in the first place.

Posted by Monte L Fullmer (Member # 2797) on 09-27-2011, 01:47 PM:

I can see one small keynote here:

quote: Justin Hamaker
4 screens using Ushio bulbs have silver screens for 3D

Silver screens are more contrast laden (giving the image a metallic look, thus maybe a different reflective output, and ?, aren't silver screens the more of the light eating type than matt white screens-why the need for higher powered bulbs?) where matt white screens are more even with light distribution and has better reflective results.

Not so much a bulb issue, but a screen issue here.

-Monte

Posted by Dave Macaulay (Member # 813) on 09-27-2011, 06:10 PM:

Silver screen is required for 3D unless you have Dolby 3D with the comb filter glasses or XpanD or similar with active glasses.
A silver screen looks much brighter with a given light source than matte white, but it will have a serious hot spt related to the angles between you, the screen, and the projector. You need a bigger bulb for 3D, not for the silver screen. All digital 3D systems so far reduce the light level a lot. Usually a correctly sized lamp in a silver screen room will be over 16 ft-L in 2D at minimum lamp power and just make 6 ft-L in 3D at max power.

Posted by Mark Gulbrandsen (Member # 72) on 09-27-2011, 08:45 PM:

quote:
Not many 4K lamps can go 1500 hours under warranty!

Ushio, LTI, Osram and all make lamps that go that long under warranty. They are not necessarily on the the higher output side of the lamp spectrum though... The 3000 watt Helios goes for 1200 hours...

I do not believe you can use any threaded CXL type lamp in an NEC... Strictly pin type lamps and the lamps should be on the NEC approved list just to cover all possible warranty aspects...

quote: Steve Guttag
In the case of the NEC, they have a DXL-20SN3 that is a 9000-lumen lamp and has a warranty life of 2400-hours. That lamp will likely out perform, over its life any other 3K lamp you put in there and cost less/hour as well...including on electricity.

We are running a couple of these lamps, one even in 3-D mode with a Real-D X-L. It's a great lamp for the first thousand or so hours but the output declines quite a bit after the half way point. It's cheap to run though and would be fine for 2-D up to about 30' wide 1.4 gain. The one we are running on 3-D will be switched to a 3kw Helios... The Helios costs less than the 2kw Ushio does and puts out better light but they will be using twice the number of lamps. It'll still be less expensive than using a 4kw. That 3kw Helios lamp seems to hold it's light level very constant over it's entire 1200 hour life, throughout a dozen or so we have been running.

Another thing about the NEC... You can use it's internal light meter as a basic guide to aligning the lamp but doing a final touch up with white light on screen and a meter generally nets one better brightness results.

Mark

Posted by Monte L Fullmer (Member # 2797) on 09-27-2011, 08:53 PM:

quote: Dave Macaulay
All digital 3D systems so far reduce the light level a lot

..is that so one will not see the "ghosting" thing with 3D presentations, and RealD does the "ghostbusting" trick to eliminate that issue?

quote: Mark Gulbrandsen
internal light meter as a basic guide

..is that the peakhold section of bulb alignment after installation?

Posted by Mark Gulbrandsen (Member # 72) on 09-27-2011, 08:59 PM:

No, not the peak hold part but the general light level display along with it. The peak hold just makes it easier to grab the peak reading when you go through it so you know to stop and go back to it. And the general light level display is just that... a general light level indication not refrenced to anything in particuluar. Using a light meter and setting the level to 14-16 fl is still the right way to do it with any D-Cinema projector period.

Mark

Posted by Steve Guttag (Member # 268) on 09-27-2011, 11:02 PM:

Mark, your findings on the Helios 3K is inconsistent with my own.

I have not don't an exhaustive study on the DXL-20SN3 but I have used its kin in other brands of projectors...the results have been very impressive.

A 1.4 gain screen is often too high a gain for 2D since the sides/corners will fall out of spec unless it is curved properly. Remember the 14fL center reading is only based on the sides being 85% of center (or better). I believe they do allow "cinemas" to drop to 75% of center. I 1.4 may just barely hit that but it would likely depend highly on the room's geometry.

Which model 4K from Osram or LTI has a 1500 warranted life or better? Yes, the smaller lamps do but what about in the 4KW range? That was the lamp in question.

As to the pricing on the Helios...are they really going for under $500/each? If not, they are not cheaper to buy two than one Ushio DXL-20SN3