Rory

I agree that most of us on Film-Tech really do care about presentation quality. Unfortunately, there are many theatres who don't seem to realize that poor presentation quality will drive audiences away. Audiences may not complain about poor presentation, but they won't come back again. "Film Done Right" is hard to beat. "Film Done Wrong" is a poor excuse for Digital Cinema or home theatre to take over (BTW, Digital Cinema will likely suffer from the same short-sighted cut-cost-to-the-bone mentality). It's penny-wise and pound-foolish to neglect maintenance.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

Let me tell you, once I get confident at changing bulbs, things are going to change around here.

You can certainly get more life out of a 4k than 1,000 hours. You don't stop using your car after the warranty expires do you?

In most instances you can safely run for around 2,000 hours on a 4k in a modern well ventilated lamphouse. Recent lamphouses are so much more efficient than a 30 year old unit.

Most lamps will give sure signs that they are nearing the end of their life: flicker becomes evident, envelope can blacken, ignition takes more than one strike, light fall off etc.

Our circuit is over 1,500 screens, if I advocated changes on 4k's at 1,000 hours we would be out of business! Let me balance that by saying we work closely with both major quality xenon manufacturers to ensure we achieve maximum light quality and life without compromising our aim of 16 flicker free footlamberts or risk of explosion.

For the record we have had 6 explosions in recent years and all occurred within the lamp warranty hours. The explosions were caused by manufacturing faults. We operate xenons from 1,600 watts to 7,000 watts in almost every type of lamphouse: Kinoton, Cinemeccanica, Strong, Christie, Xebex, Bauer etc.

If the average screen operates for 5,000 hours per year, you can see how incredible the xenon lamp costs would become if we swapped at 1,000 hours regardless of lamp condition. Of course there are many variables in operating conditions: airflow, cold strikes/hot strikes, continuous operation, angle of lamp operation, amount of ripple from power supply, poor installation and handling, fluctuating local supply etc.

Yes, I know I can get more than 1000 hours from a 4k (as I wrote, I've gone to 1200, and 1100 is not that uncommon), but I've had enough of Xenon bulb explosions and mishaps to just order new bulbs in time. The warranty time of the Osram 4k's is much shorter than 1000 hours, btw. I think it's around 250 or 300 hours. I'd never go to 2000 hours with either our present lamphouses or our present rectifiers. I know my predecessors did, but they had a lot more explosions than I have.

Our lamphouses are about 30 years old (Cinemeccanica Zenith 4000; not great but mostly they do what they're supposed to), and so cooling could probably be better. I know it could be better, btw; the aux mirrors are a bit too easily burned. I guess I could try to locate a newer model but from what I gather, most of the new 4k lamphouses available today hold horizontal bulbs, something I never much cared for. And I doubt management would give me the new lamphouses right now; we have other worries right now.

Also, we run the bulbs at around 130A which also adds up. They'd probably take another 200 hours at 120A, but we wouldn't get the kind of light we need.

When a bulb blows, replacing the main mirror is VERY costly. The aux mirror is not free, either, but it doesn't cause a heart attack when you tell the manager how much a new one will cost.

Another thing is that I've found that after a 1000 hours, the light is just not as good as it could or should be. If we're running 70mm it's almost unacceptable (another monetary question, really; we could by new 70mm lenses but they cost a LOT and we don't run 70mm that often so...) Around 1000 hours, Scope also begins to suffer, and that's a shame. Don't get me wrong; I check the light often enough, and adjust it as soon as there is any reason to, but the lamphouse is too small and the screen too big...

So would I continue using a car after its warranty's expired? Absolutely, and I do. But a period equalling four times that warranty period? Would I continue using the car for longer trips where I would have to really rely on it, really count on it, no matter how far I'd have to go or who'd ride with me? Would I continue using that car if I noticed new puddles of oil and water below it on the parking lot every time I had to leave for yet another journey?

Those precious few times I work at the local multiplex, I really couldn't care less about how long they've had a bulb in any given lamphouse. I know they often go past 10 000 hours using 1.6 k's. The 1 k's go...well, I don't even dare to guess.

Do I worry about an explosion? No, not really. There's an aluminum mirror that simply won't break, and there aren't any aux mirrors you should worry about. It takes five or ten minutes, tops, to replace a bulb and get the show running again. A 1 or 1.6k bulb costs a fraction of what a 4k costs, and I don't have to think about their budget. Why should I worry? Most of the time, a bulb will blacken to the point of being unusable before exploding anyway, so why should I worry?

I know the Cinemeccanica Zenith lamphouses well. They were probably one of the most efficient verticle lamphouses around but cannot compare to the efficiency for light and cooling of a moderm horizontal unit.

You know your xenon environment better than I do and the rectifier has a lot to do with it. We ran 5,000watts in our Zenith lamphouses and always got around 2,000 hours. You will find the warranty for a 4k or 5k for most manufacturers is above 500 hours.

We run 4k and 5 k lamps in Kinoton and Cinemmeccanica Vic 5 lamphouses with no problems of quality flicker free light at well over 2,500 hours in most instances. If you are really concerned at running lamps over 1,000 hours have an air-flow check of the Zenith and check how much AC your rectifier is not correcting. If you can find just 500 more hours you will have big savings on your theatres number one consumable cost.

I have never known a steel mirror to withstand more than one or two explosions without the mirrored surface being effected to the point where it drastically restricts screen brightness. An efficent cold light mirror may dissappear in a bang but lets much more heat pass through it instead of forwards onto your film and gate.