But leaving them on full-bore doesn't seem like it would be the greatest idea in EVERY case.

For those who haven't read the first few posts...over in the "Misuse" thread...

I complained that a new projectionist had left a Xenon burning without rolling film. (Forget the fact that she was totally unaware that she had ignited the lamp by accident.)

Jan added that she left hers burning all the time...but she also added that she's running 10 shows a day.

I'm talking about a theatre that has three shows a day...and we were about 4 hours away from showtime when I noticed the lamp burning.

How does one decide when to leave xenons burning and when to extinguish them between shows?

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And, hey! Let's be careful out there.

Personally, I don't leave them on between shows. Runs the power bills up too high. That's the "Con". I discovered there was no real savings in the long run. It almost balances out.

There is also a possibility that if you leave them on and the operator forgets that the movie is over and does not close the hand douser, the flimsy shutter in some of today's machines could become warped or burned. I don't think anyone wants to blast a flimsy shutter with a 2.5kw or higher lamp, or any lamp for that matter.....

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I would think you would be risking heat damage to the print if the bulbs were left on continually, even with the little dowser plate or lamphouse shield blocking the light/heat wouldn't there be the matter of heat via conduction? I have trap cooled 3K's and the traps still get pretty hot while running because my ventilation is getting steadily worse. In fact, when the freon went out on the booth A/C we had a little heat damage to a print.

If you were to leave bulbs on all the time then you'd better have really good ventilation, trap coolers, and keep the booth really cold.

John made a good point, what if your dowser cue doesn't work and the lens gets wrecked because your operator was on the phone or dropping the kids off at the pool?

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Take a look at how many amps these zenons run. Calculate that into cost of leaving it on all the time all day versus the cost of POSSIBLY shortening its life by starting it an extra four or five times a day. It just doesnt add up, and besides you wont actually know if you are saving the bulb or not until you wear it out or burn it out. In my experience, I have had bulbs last four weeks and I have had bulbs last 18 months. So it really is up to so many variables, that there would be no need to leave them on all damn day because you MIGHT save a few hours on the bulb, at the cost of astronomical light bills and possible equipment damage.

My advice, turn it off!!!

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On the issue of leaving computers on 24/7, there is much discussion on this. If you do leave it on 24/7, you run a risk of total failure if you suffer a power outage. The reason is that with this practice the contacts on the board will expand so far that during a long power outage, the contraction of the contacts can cause a MB failure, which can also lead to other failures such as HD failure etc. If you leave it on 24/7, make sure you have a battery backup, as most power failures are short term.

Just a thought.

I agree with you...I don't think I've ever seen a household bulb expire while it's already turned on. Always when it's just turned on. So, I see your point.

But I think I'm going to go with shutting them down between shows...longer intermissions here.

BTW, I leave my computers on 24-7 too. I reboot once in a while out of superstition, though.

...and, yes, I have them all on UPS battery backups that offer about 10mins of power.

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And, hey! Let's be careful out there.

~Manny.

I do think that it depends on your particular booth and equipment.
In a change-over booth, leave em on, but let them shut off after a show with a multi-plex/platter operation.

Here are some scenarios you may cover:

Think of your lense probles should your change over fail! Also, the bulb heat can cause change-over blades to warp such as the Christie. But Christie has attempted to solve this problem.

I have also seen some small independant houses where the lamphouses were in delipated condition and the lamp house dousers did not do much good! I have also seen some independant houses running platters without any kind of changeover or failsafe assembly!

If you do opt to keep lamps lit, is your "projection" staff intelligent enough to properly look after them?

I guess that the bottom line is that bulb wear can be reduced by keeping them lit for at least 1/2 hr before shut down...that frequent striking will lead to excessive wear, and this is covered in many bulb and lamphouse manuals! But keeping them lit for extra time will also wear them down.

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