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Topic: Lamp house On and Off every 20 minutes is bad?

Ted Wilby
Film Handler

Posts: 3
From: Spring City, PA, USA
Registered: Jan 2001

posted 10-30-2002 02:50 PM

So... I'm learning a lot here. I see something about not shutting the Xenon lamps off between reels. That's how I was taught, so your saying it's Bad? Why and how do I explain that to my Manager and the other projectionists? We show both one hour reels and 20 minute reels depending on if the show is here for a week or one day. We switch the lamp houses on Manually, right before the reel change and the other as soon as the reel is done. We have two Strong Lamp houses with about 2000watt bulbs I guess. I'm not up on the tech details. That's why I'm here. I'm learning.

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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999

posted 10-30-2002 02:56 PM

Hi, Ted! I ran two, two-projector booths this way for years. I don't know that there is enough of a difference in shutting them off between hour-long reels to matter much. I would be afraid of too much heat build up to leave them on that long with the dowser closed. Especially on Strong Lumexs and Super Lumexs, which is what I had.

However, when I ran dailies on movie shoots, with reels no longer than 10 minutes tops, I left them both on continuously. The screening room environment probably would be too much on/off cycling to turn them off between rolls. Also, I felt there was too much risk the incoming lamp wouldn't be there when I needed it.

Btw, if you haven't noticed, I'm playing the banjo in my picture at left. Now, all we need is a mandolin player and a guitarist, and we can form the Film-Tech Bluegrass Band!
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Better Projection Pays!

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Ted Wilby
Film Handler

Posts: 3
From: Spring City, PA, USA
Registered: Jan 2001

posted 10-30-2002 03:10 PM

Well, of course last night, we had one show, so shutting the hour reels on and off is a given, but if I had two evening shows...

Where is North Hampton, are you near by???

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Tim Reed
Better Projection Pays

Posts: 5246
From: Northampton, PA
Registered: Sep 1999

posted 10-30-2002 03:13 PM

Every installation I've ever seen with hour-long reels, shuts the lamps off between reels.

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Better Projection Pays!

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000

posted 10-30-2002 03:16 PM

Assuming your dowsers can take the heat, I agree that it's probably best to leave both lamps on if you are running < 20-minute reels. But for 1-hour reels, I'd turn off the lamp between reels, and ignite it a few minutes before changeover. (I assume your sound system is not picking up any noise from the xenon lamp ignition pulse, which would be very annoying to the audience).

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
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Joe Beres
Jedi Master Film Handler

Posts: 606
From: Minneapolis, MN, USA
Registered: Nov 2000

posted 10-30-2002 03:24 PM

I agree with John P. here as far as what to do with the 2000' and 6000' reels. If you need an explanation to take to the management, the theory is that having several lamp ignitions in an hour shortens the lamp life. I run 2000' reels and leave the lamps on for the duration of the show. I do that partly because the ignition sends a pop through our sound system, but hopefully our new lamphouses will not cause the same problem. Even if they don't, I will continue to leave the lamps on. In theory, the lamp will last a bit longer, and I won't have to worry about any ignition problems that could possibly (however unlikely) come up at a point in a show (right before a changeover) when I would have no time to fix or troubleshoot the problem.

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Bill Gabel
Film God

Posts: 3873
From: Technicolor / Postworks NY, USA
Registered: Jan 2002

posted 10-30-2002 03:27 PM

I run in a studio screening room environment. I leave them
on most of the time, during the day. Because by turning them off
it takes time for them to go back to the right color tempature.
Because I work with the editorial departments, I have to check
the lamps for different formats (Sup35,1.66, 1.85, 2.40). We handle
print checks, opticals, we are on call, all day. these lamps run all day sometimes. When we would go out on a premiere set-up, we would strike the lamps 20 minutes before the show.

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Steve Kraus
Film God

Posts: 4094
From: Chicago, IL, USA
Registered: May 2000

posted 10-30-2002 05:39 PM

Ditto what Bill said. At my screening room the lamps stay on unless I think the interval until one or the other is needed again is at least 45 minutes.

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Daryl C. W. O'Shea
Film God

Posts: 3977
From: Midland Ontario Canada (where Panavision & IMAX lenses come from)
Registered: Jun 2002

posted 10-30-2002 05:45 PM

In the last changeover house that I worked full time in I used to get about 3000-3500 hours out of 1600W Osram bulbs shutting them off between 6000' reels. I was amazed at how long those things lasted while still putting good even light on the screen. Also, I always turned them on about two minutes before the changeover to give them a bit of time to calm down, unless it was in a far booth... sometimes I ended up turning them on between motor queues.

I think the important thing, if you're going to be shutting the lamps off, is to ignite the bulb in time to find out whether it's going to ignite, or if it's going to die. Hopefully, in the event of a lamp failure, this will give you enough time to unload the incoming reel to have it ready to rethread on the outgoing projector so that you are only off of the screen for about 30 seconds.

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Bill Gabel
Film God

Posts: 3873
From: Technicolor / Postworks NY, USA
Registered: Jan 2002

posted 10-30-2002 06:29 PM

See that's in a regular theatre environment, you could get away with
striking your lamp 2 minutes before a change-over. But not in a Studio screening room environment. Because when your are working with the editor, director, director of photography and the rest of the crew. They are looking at the picture they just shot. They are looking for problems with focus , color, framing. So if you started your lamp 2 minutes before a change-over with them in the theatre.
The intercom would be ringing off the hook. To see why the picture
looks bad. It takes about 10-15 minutes for the lamp to be ready.
I have worked many screening rooms and had no trouble with any of the
crews about poor light on the screen. I had Godfrey Reggio the director said two months ago that we had better light on our screen.
We ran a screening of "Naqoyqatsi". The day before they ran it over
at Technicolor's screening room. Film Light Done Right

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 10-30-2002 07:11 PM

Depending on the type of ignitor Several manufactures state that between 40 min to 1 hour 10 min if taken off the life span of the lamp per ignition
So if a reel is less than 6000' the lamps stay lite

That is why some manufactures provided standbye mode to lengthen lamp light yet decreese heat and electrical consumption between reels

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Daryl C. W. O'Shea
Film God

Posts: 3977
From: Midland Ontario Canada (where Panavision & IMAX lenses come from)
Registered: Jun 2002

posted 10-30-2002 08:07 PM

Bill I understand the reason, I also agree with it. I was just letting Ted know what kind of results I've had with shutting the lamp off between 6000' reels. I know that in two minutes the lamp hasn't even heated up all the way and it still changing in colour temp.

My main reason for shutting the lamp off in the past has been projection booths that are already in excess of 30 degrees celsius (during the winter, hotter in the summer) and not being able to stand the extra heat.

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Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999

posted 10-30-2002 10:19 PM

I leave them on, even when playing 6000ft reels. That way you don't have to even think about color stabilization and in two of the three theatres that have xenons, two of them have an audible enough snap that's enough for me to forgo shutting them down. In a 20-plex booth that I visit regularly, they leave all the lamps burning all day long. Most are 2000w; the question of damage to the dowser doesn't seem to be an issue (they've been doing this for decades so I guess they are not having any burn-throughs).

There is one booth where I freelance that uses an Italian-made "portable" projector (yah, portable if you are the Hulk) and its igniter makes a sound louder than a Star Wars proton cannon -- it eliminates any choice about whether to leave it on or not!

Frank

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 10-31-2002 08:57 AM

For 2,000 foot reels I'd always leave them on except when running nitrate. In order to minimise heat build-up around the gate area I was taught to ignite the lamp on the incoming projector between the motor and the over cues. I did ask the chief who told me to do this whether it might not be better to strike the lamp before lacing up, but he advised against this on the grounds that (i) if the projector chassis is properly earthed then sparks aren't an issue, and (ii) a couple of minutes' residual heat build-up is a much greater risk than the possibility of a stray spark from the ignition. Similarly, we'd kill the lamp on the outgoing projector immediately after the changeover, while the tail was still running out.

There are three potential drawbacks with this: firstly, switching on the rectifier and striking the lamp during the 3-4 seconds between the two cues takes practice (though it's surprisingly easy after a few tries), secondly that the picture doesn't look great during the first 2-3 minutes of each reel (especially with nitrate dye-transfer prints), and thirdly that if the incoming lamp fails to ignite then of course you are totally and utterly screwed. But with me it never did, and in any case I'd much rather by screwed by an unscheduled intermission than a nitrate fire.

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 10-31-2002 10:55 AM

So why do Kinoton FP-30s (and possibly other models) use the motor switch to control the lamp as well? Striking the lamp every 20 minutes (and only 8 seconds before the first frame of the reel) seems like a really bad idea, based on everything that I've been told. It just seems very odd to see this sort of design flaw, considering the amount of engineering that has gone into other aspects of the Kinoton machines.

I do turn off lamps when running 6000' reels except for premieres and "special events" and any other "important" situation. I haven't run anything larger than 2kw lamps in changeover booths, though, and don't know about the heat issues with larger lamps.

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