Sooooo, here goes.

This must begin with the story of a twin that had Cinemecchanica V8 projectors with the 13,000' reels and 1KW xenons -- VERTICAL -- with excellent ventilation. The lamphouses barely even got slightly warm to the touch.

The daily routine, which I had some influence in establishing as I was the projectionist there for about a year shortly after it opened, was to switch on both lamps only ONCE at the first show, then they stayed on the rest of the day. This minimized ignitions, and I have always had the belief that if you can run with minimal ignitions, your bulb will last longer. Naturally this also requires that one be in attendance to close the hand dowser as each show ends.... so maybe it wouldn't work the way things are done today.

The last time I checked, 1983? not one, but BOTH of these xenon bulbs were still going with about 28,000 hours on one and a smidge over 30,000 on the other.

The screen illumination gradually became weaker, of course, but it was my favorite theatre to see a movie in, with its fast lenses and razor-sharp screen image. Color quality was excellent.

This has helped to cement in place my personal preference for a smaller-sized screen with a razor-sharp picture over big-screen-itis with a xenon that's so bright it causes flicker. Oliver! was a movie that looked especially good, and my dvd copy that I enjoy today is similar as to color balance and sharpness.

Many of the folk here are probably familiar with the phenomenon that people won't know what is wrong precisely with a given house; just that every time they attend; go home with a headache. And might not want to go back.

A brand-new xenon bulb can be extremely bright and may need to be run with lower current for a while. This calls to mind another nice thing about the Cinemecchanica xenon power supplies: you just turned the large round wheel on top to adjust... sooooooo simple! The entire system was simply a delight to work with.

Thus, I offer for argument that Old Lamp is better, with a mellifluous light, not too bright, and easy on the eyes!

And you sure can't complain about 28,000 hours, either!

Will look forward to the consensus of opinion here.

Theatres should be nice places to see movies in, but we have no theatres here in Billings, thus it's going on 12 years now since I saw a movie in one. Occasionally I'll catch a show in Denver or another city when I'm there, but not often.

j.

Running a xenon lamp until it can't meet the SMPTE standard and is on the verge of explosion is "Penny wise and pound foolish".

------------------
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 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

My point is that this bulb, if it has not darkened and is in otherwise good condition, may be no more dangerous than an off-brand bulb that is approaching the end of the warantee period. Each bulb needs to be treated on its own merits. The early xenon lamps we ran in a vertical position usually began darkening at 1 1/2 to 2 times the warantee period and were only pulled when the condition of the lamp began to look bad or there were the telltale striking problems.

That said, I suspect the bulb in question is nearly black and has severely pitted electrodes. If that is the condition, I too would recommend immediate replacement.

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I thought there would be a general reaction along the feelings you guys have expressed. By the way, they were Osram bulbs, and no, I am not being paid anything for this endorsement!

Somewhere between 2-4,000 hours, we WERE starting to wonder a little, and most assuredly the question came up of: If the bulb explodes it will shatter the glass reflectors [there were 2, I think] and that will be expensive; so we checked into the cost of spare reflectors and then did some more figgerin'.

A calculated risk to be sure, but we were already well on the winning side of the equation. The decision was to order in one set of replacement glass reflectors and a second spare Osram bulb, all kept in the booth. Life went on, and the hour counters kept ticking... a little like a time bomb, but you couldn't hear the ticks while the projectors were running... so, "What? Me Worry?" Besides, I didn't have to stay in the booth anyway, so I felt my risks of a heart attack if/when the bulb blew up were minimal.

My memory is a little faded now, but I think somewhere around 7-8000 hours I did another calculation, and the cost per hour of xenon light was down to under 25 cents, and dropping steadily! About this time I moved on to another house. Years went by. The bulbs kept going until the little twin finally closed, unable to meet exorbitant demands for unreasonable rents. It was in a shopping center.

IMPORTANT =====> the picture on both screens was of excellent visual quality, still beautifully sharp and the theatres had a good reputation for their screen quality.

Mark, John and Jerry, I certainly agree as to the value of standards. They give us something to go by, surely, but should not become dictatorial in and of themselves in all situations, and I offer up this story as an example of something that didn't meet standards, to be sure, but certainly worked well! I've always had 20-20 vision and know a good sharp picture when I see it, and have "golden ears" from a lifetime of listening to classical music.

It is also possible to have a dolby system tuned up perfectly according to specs and the instruments, and in the house it sounds awful. From this point it becomes an "art."

For my next post, I think I'll tell the story of the porno house with the Altec A2 speaker system on stage, and what I did.

j.

SMPTE standards are voluntary, and not "dictatorial". But the artists who make movies decide on the "look" of their art in lab screening rooms that are carefully maintained to match the 16 footlambert aim specified in SMPTE 196M. Showing those same films in a theatre at much lower screen luminance MAY look acceptable, but it doesn't reflect what the director and cinematographer intended. Compared to proper screen luminance, a picture with flat highlights, dull colors and murky shadows isn't "working well".

I presented a demo "Brighter is Better" at ShoWest and SMPTE that clearly showed the loss of quality that occurs in underlit theatres:
http://www.kodak.com/US/en/motion/newsletters/reel/spring98/pointers.shtml
http://www.kodak.com/US/en/motion/newsletters/notes/march2000/pytlak.shtml

To evaluate proper light level, you must MEASURE it. The eye quickly accomodates to low light levels, so the images look "okay". But put up against an image projected at the proper light level, the difference in quality is obvious!

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30.000 hours????? Is it possible?
I think that after 30.000 hours (7.5 Xenon bulbs at 4000 hours) the money saved can cover the money for a new mirror and eventually others damages...
But If I have a 30.000 hours lamp into my lamphouse, I would not stay near that damn timer bomb...

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I have never been able to understand why, with these facts known... wouldn't lots of screens be equipped with vertical Osram bulbs? Probably because those corporate types at the top are all ----[CENSORED]---- and the unprintable words have been expressed many times in other posts here so I'll leave it at that.