Question about screen type

[Ryan Gallagher]

So I spoke with MDI and we figured out that I have a northview screen with a 1.8 gain. They said that is too much again for my projector the NC1200C with the 2000watt bulb. I guess it’s reflecting too much light which is then causing me to be able to see the screen through the movie? I’m trying to learn what gain is on the Internet right now to try to understand better. He recommended either 1.0 or 1.3 gain based on my projector and the distance from the projector to the screen. He said it should not feel sticky and may have melted slightly under high heat in the theater maybe said that it’s probably due for swapping out. Can’t wait to find out the pricing of a new screen ?! Thanks again for everyone’s help I am getting a lot of value out of this group and am learning a lot about my theater.

Yeah 1.8 is considered a "high gain" screen (ie very reflective) surface. If it is actually sticky and not just shiny then yeah, something materially is starting to go. Other than heat like MDI suggested, if your room was ever a smoking permitted space, nicotine can actually break down a lot of those plastics and cause them to get sticky too. The other suggestion of perhaps someone having cleaned it improperly is also a possibility.

When you say "see the screen", are you meaning you see variations across the field caused by the screen, or are you actually seeing a brightness hotspot that moves relative to your location? (as Paul suggested). The former would indicate some kind of coating damage or uneven dust deposition, the other is just the normal behavior of high gain screens.

Personally, if it's not actually degrading (sticky) or damaged due to cleaning attempts, I'd wait and bundle your screen swap with a larger upgrade when you decide to move that room 4K. Xenon vs Laser will inform which screen fabric to invest in during the upgrade. There is also the factor that I wouldn't put a 15x21' screen back in unless you have motorized masking. I would lean towards a one of the standard scope or flat ratio screens, which may entail replacing more than just the fabric and add to the cost.

In the mean time you might want to actually meter your reflected brightness... maybe running the 1200C at something below full lamp power is actually better to hit the 14fL DCI spec?

I'd just hate to see you throw a bunch of money at an odd-sized screen for your existing 2K xenon, only to find out a couple years later you should have gotten a different screen fabric for 4K Laser.

[Mike Reed]

I'd just hate to see you throw a bunch of money at an odd-sized screen for your existing 2K xenon, only to find out a couple years later you should have gotten a different screen fabric for 4K Laser.

Thanks for the fast reply, I know the screen has been up there for just over nine years. It was replaced in October 2015. The theater has not been smoked in since the 90s. I didn’t realize 15 x 21 is an abnormal size for a theater. I don’t know the exact size of my other theater but I know it’s wider but the same height I believe. I don’t know if I can do more wide on the small side theater? Just the way the theater is set up right now. I know there is a jump to laser at some point in my future just don’t know when. MDI Said they can retrofit these NC unit units for laser which can save some money I guess.

As far as brightness goes there are no hotspots on the screen. All I can explain is it seems like you can see the screen sometimes through the movie. I only know how to adjust brightness on these NEC projectors with those XYZ access Allen wrench turn screws. Last I had was a peakhold of about 700 on that NC1200. When I first put in the new bulb in it in February it was around high 300s. I kept thinking it was not as bright as it should be So I’ve been able to get it up to about 700.

You are right about the screen and projector I don’t want to waste money I don’t have too.

[Ryan Gallagher]

Thanks for the fast reply, I know the screen has been up there for just over nine years. It was replaced in October 2015. The theater has not been smoked in since the 90s. I didn’t realize 15 x 21 is an abnormal size for a theater. I don’t know the exact size of my other theater but I know it’s wider but the same height I believe. I don’t know if I can do more wide on the small side theater? Just the way the theater is set up right now. I know there is a jump to laser at some point in my future just don’t know when. MDI Said they can retrofit these NC unit units for laser which can save some money I guess.

As far as brightness goes there are no hotspots on the screen. All I can explain is it seems like you can see the screen sometimes through the movie. I only know how to adjust brightness on these NEC projectors with those XYZ access Allen wrench turn screws. Last I had was a peakhold of about 700 on that NC1200. When I first put in the new bulb in it in February it was around high 300s. I kept thinking it was not as bright as it should be So I’ve been able to get it up to about 700.

You are right about the screen and projector I don’t want to waste money I don’t have too.

If you could find a test pattern or a trailer where you notice the effect, maybe a video would convey what you are seeing.

[Ioannis Syrogiannis]

As far as brightness goes there are no hotspots on the screen. All I can explain is it seems like you can see the screen sometimes through the movie. I only know how to adjust brightness on these NEC projectors with those XYZ access Allen wrench turn screws. Last I had was a peakhold of about 700 on that NC1200. When I first put in the new bulb in it in February it was around high 300s. I kept thinking it was not as bright as it should be So I’ve been able to get it up to about 700.

When changing the lamp, you need to focus the lamp to its highest output by using the three knobs for each axis of the three (X, Y, Z). If not, you may have great heat losses and higher than necessary temperatures.
The brightness of the lamp (and wattage) is set in a certain setting of the DCC, that you can have different, depending on whether you have a Flat or Scope preset.
What is the proper value, is a matter of setting in compliance with the measured output. A technician should have a meter with their tools, if asked to carry, but there are a couple for xenon lamps that are not nearly as expensive as colorimeters or spectroradiometers are.
What I want to rely: You focus the lamp as best you can through the Allen keys, after 10-15 minutes of having the lamp on and screening white test pattern.
You set the brightness through the DCC program and save the proper setting for Flat, Scope, or other.
There might be special occasions where you might need to get the lamp slightly out of focus (mostly by defocusing with the Z knob), but that is very rare and I wouldn't bother giving much thought to it, unless you can't bring the brightness down to proper levels through wattage.

[Stefan Scholz]

In my view, screens are due for replacement after 8, max 10 years. The base material degrades, coatings degrade,
softeners vanish, and what once was a white surface slowly becomes yellowish or brownish.
Screens are not really expensive, as long as you don't insist on one of those newer high tech 3 D surfaces, they offer
with benefits. These are costly. Matte white in standard digital perf (meaning unevenly distributed punched holes to avoid moire) is
pretty reasonable. Often the cost of shipping as a roll as special freight is higher than the screen price.

[Mike Reed]

When changing the lamp, you need to focus the lamp to its highest output by using the three knobs for each axis of the three (X, Y, Z). If not, you may have great heat losses and higher than necessary temperatures.
The brightness of the lamp (and wattage) is set in a certain setting of the DCC, that you can have different, depending on whether you have a Flat or Scope preset.
What is the proper value, is a matter of setting in compliance with the measured output. A technician should have a meter with their tools, if asked to carry, but there are a couple for xenon lamps that are not nearly as expensive as colorimeters or spectroradiometers are.

So my DCC has the lamp set at 71% 1410W output. I can adjust this manually to have more brightness. But would I have to manually do this before every show? Or can I save a new brightness setting to higher brightness like 90% output? Thanks!

[Leo Enticknap]

Yes, you can save the brightness setting. Go to lamp, adjust to the required setting, then memory list > entry, as so:

image.png

You can then link the lamp setting file you created to a "title" (NEC-ese for macro), as so:

image.png

For a xenon arc lamp, I would advise against running it at more than around 90%, though: it increases the odds that it'll start to flicker before it reaches warranty hours. Maxing out a 2kW lamp for the last 200-300 hours of its warranty life is likely no problem.

[Ryan Gallagher]

So my DCC has the lamp set at 71% 1410W output. I can adjust this manually to have more brightness. But would I have to manually do this before every show? Or can I save a new brightness setting to higher brightness like 90% output? Thanks!

If you don't have a proper meter, It would probably be safer to assume the last time these lamp memory values and associated presets were adjusted was by a visiting tech with a relatively new lamp?

Unless the wattage of the lamps being purchased (or perhaps brand) has changed since then, there is not "much" call to revisit them. But you never know, lots of cinemas ran lamps below DCI spec for longevity reasons, it would be good to learn where you stand after a lamp position calibration and properly metering the most common formats.

I'm spoiled by Christie's Lamp-LOC wizard, if I only had manual adjustments I'd be tempted to leave them alone unless I was fighting and obvious brightness or field issue on screen. We were also undersold on our projector originally... to get 14fL we have to be at 100% rated lamp power with a new lamp, and that might fall off towards the end of lamp life. I only know this cause SXSW occurs here annually and studios bring techs to meter and shoot colors. But we never get to the end of the warranty period, cause we pop in a new one annually for the festival.

[Leo Enticknap]

NEC has an equivalent to Christie's Lamp-LOC and Barco's CLO, but it's so unreliable as to be practically useless (IMHO). If you have one of these projectors and are trying to maintain DCI level, a light meter is an essential piece of equipment for the booth.

One of the theaters I worked at (the Aero in Santa Monica) had a particularly irritating throw and screen size combo, such that a 3kW lamp was too bright for flat at the start of its life (i.e. even at minimum amps it gave 17-18 ft-l and didn't get down into the1 14-16 range until it had done 500 hours or so), but not bright enough for scope after around 1,000 hours (below 12 ft-l with the current maxed out). This place regularly did studio rentals and festivals, and the studios' tech checkers were constantly complaining about it. We had to keep a separate 4kW bulb in the booth specifically for scope shows for fussy customers. Add to that the 7kW lamp that was needed for 3-D shows using the Dolby filter wheel system, and I've never had to swap out lamps as often as when I did at that theater! And of course the projector was not a Barco (it was an NC3240), so swapping lamps was not as easy as pulling and replacing a removable lamphouse module.

[Ryan Gallagher]

NEC has an equivalent to Christie's Lamp-LOC and Barco's CLO, but it's so unreliable as to be practically useless (IMHO). If you have one of these projectors and are trying to maintain DCI level, a light meter is an essential piece of equipment for the booth.

One of the theaters I worked at (the Aero in Santa Monica) had a particularly irritating throw and screen size combo, such that a 3kW lamp was too bright for flat at the start of its life (i.e. even at minimum amps it gave 17-18 ft-l and didn't get down into the1 14-16 range until it had done 500 hours or so), but not bright enough for scope after around 1,000 hours (below 12 ft-l with the current maxed out). This place regularly did studio rentals and festivals, and the studios' tech checkers were constantly complaining about it. We had to keep a separate 4kW bulb in the booth specifically for scope shows for fussy customers. Add to that the 7kW lamp that was needed for 3-D shows using the Dolby filter wheel system, and I've never had to swap out lamps as often as when I did at that theater! And of course the projector was not a Barco (it was an NC3240), so swapping lamps was not as easy as pulling and replacing a removable lamphouse module.

That sounds annoying (but necessary). As we are on the brightest supported lamp. our only festival headache tends to be a studio tech being aware of Christie's 120% power option, but we have to remind them that only is available with certain lamp models installed, not this one, then they usually live with what they got.

If we were really trying to manage lamp life we would have been having *new* installed for the big festival, but keep another low hours new one around for off schedule major premieres. Then at the year mark move that still serviceable lamp into our smaller theatre that only needs like 50% lamp power... but it only recently got an identical projector which presented that option. And it's only gonna use it for a handful more hours before closing for major reconstruction and projector upgrade.

Last time a festival did a digital 3D premiere here they rented in a different projector and placed it in the balcony. We certainly don't have the brightness for 3D, but i'd rather swap a lamp than haul a projector up 6 flights of stairs.

[Mike Reed]

Yes, you can save the brightness setting. Go to lamp, adjust to the required setting, then memory list > entry, as so:



You can then link the lamp setting file you created to a "title" (NEC-ese for macro), as so:



For a xenon arc lamp, I would advise against running it at more than around 90%, though: it increases the odds that it'll start to flicker before it reaches warranty hours. Maxing out a 2kW lamp for the last 200-300 hours of its warranty life is likely no problem.

Hey thanks for the instructions I appreciate it! WE have LTI lamps. In this case a 2000W lamp installed about 10 months ago with plenty of hours left on it. We show 8-9 shows a week on this projector. I think the increased brightness will make the viewing experience better overall.

[Mike Reed]

If you don't have a proper meter, It would probably be safer to assume the last time these lamp memory values and associated presets were adjusted was by a visiting tech with a relatively new lamp?

Unless the wattage of the lamps being purchased (or perhaps brand) has changed since then, there is not "much" call to revisit them. But you never know, lots of cinemas ran lamps below DCI spec for longevity reasons, it would be good to learn where you stand after a lamp position calibration and properly metering the most common formats.
l.

The previous owner of the movie theater installed the lamps himself over the last 10 years. So this setting has not been adjusted for a decade, probably. In fact, when I talked to the previous owner about what I felt was not. a bright enough picture, he said he didn't even know you could adjust brightness on the screen. Again, I'm doing a lot of self teaching here. And I've learned a lot, and I appreciate everyone's willingness to answer my questions and give me suggestions. Yes, I've had a tech in here once or twice.

[Ryan Gallagher]

The previous owner of the movie theater installed the lamps himself over the last 10 years. So this setting has not been adjusted for a decade, probably. In fact, when I talked to the previous owner about what I felt was not. a bright enough picture, he said he didn't even know you could adjust brightness on the screen. Again, I'm doing a lot of self teaching here. And I've learned a lot, and I appreciate everyone's willingness to answer my questions and give me suggestions. Yes, I've had a tech in here once or twice.

Adjust to what looks good to your eyes, and next opportunity get someone (or yourself) to meter brightness and do the fine-tuning. Would be good to do that towards the end of a lamp's life, and then again with a new lamp (perhaps in the same visit)... that at least would give you a upper and lower range on the lamp power to adjust through it's lifetime.

[Ryan Gallagher]

Hey thanks for the instructions I appreciate it! WE have LTI lamps. In this case a 2000W lamp installed about 10 months ago with plenty of hours left on it. We show 8-9 shows a week on this projector. I think the increased brightness will make the viewing experience better overall.

Speaking of metering, a good tool to nab that will get you in a ballpark, by no means a precision meter, but better than nothing. Hard to say no at 50$ price. I nabbed a couple previously at closer to 80$ each.

Harkness Digital Screen Checker Luminance Meter
https://www.ebay.com/itm/146280124563

These were originally intended for operators to facilitate "maintaining" a target brightness over the life of the lamp, or to quickly check screens for issues. How accurate they are for absolute fL measurements versus relative to a known good value is TBD depending on how well they have maintained their instrument calibrations.

[Mike Reed]

Speaking of metering, a good tool to nab that will get you in a ballpark, by no means a precision meter, but better than nothing. Hard to say no at 50$ price. I nabbed a couple previously at closer to 80$ each.

Harkness Digital Screen Checker Luminance Meter
https://www.ebay.com/itm/146280124563

These were originally intended for operators to facilitate "maintaining" a target brightness over the life of the lamp, or to quickly check screens for issues. How accurate they are for absolute fL measurements versus relative to a known good value is TBD depending on how well they have maintained their instrument calibrations.

Hey I will check that out thank you Ryan!