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Topic: 7000 Watt Lamphouse for DI, good idea?

Laurence Hammett
Film Handler

Posts: 16
From: Los Angeles, CA, USA
Registered: Feb 2002

posted 02-10-2005 08:52 PM

I do believe that the SMPTE spec was probably written back in the days of carbon arcs and Glass reflectors when manufacturers knew Optics, Physics etc. They used bases that had some chance of being able to be aligned and they were aligned. Time has passed. Zenon and Metal reflectors took over.

What are these "hidden" expenses you talk about??? It would seem that a high speed interemittent isn't a cheap date. Roberts system doesn't require it though I am sure he could take advantage of it.

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Gordon McLeod
Film God

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

posted 02-10-2005 09:21 PM

"I do believe that the SMPTE spec was probably written back in the days of carbon arcs and Glass reflectors when manufacturers knew Optics, Physics etc. They used bases that had some chance of being able to be aligned and they were aligned. Time has passed. Zenon and Metal reflectors took over."
Carbon or xenon light levels are light levels
I seriously doubt if those are reflectors designed for each throw if so then the purchaser is stupid as the replacment cost will be astonomical And I have yet to see a technolite installation that didn't buy new lens that alone would acount for the difference
Snake oil is snake oil as mark said getting good light isn't really rocket science

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 02-10-2005 09:45 PM

There is something seriously wrong with 5.5fl whether it is at a drive-in or not.

What is the size of the screen that has this "amazing achievement" of 5.5fl?

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 02-10-2005 10:14 PM

The main hidden expense he doesn't mention is the short life span of the short gap arc lamps. Then there is the possibility of a lamp explosion(due to the shorter life span) and the probability of loosing the reflector completely. If Roberts reflectors are made for EACH installation as you say they are then the cost would be rediculous. Then you also have to put up with Osrams STUPID warranty claims system which rarely ever works in the customers favor. All in all it amounts to higher exhibitor operating costs! On the other hand high speed movements in excellent shape can be had for the same price as a good regular speed movement and sometimes much less because few are familiar with them. Yes, they are a bit more scarce but worth searching out. Its a simple improvement that typically yields at least 30% more light on the screen and an improvement that anyone can make without major surgery or lamphouse replacement. Lenses also matter but in some cases older 4" diameter lenses will actually yield more on screen light(with a bit lower contrast)than the newest lens designs will. BTW: Carbon lamps were much more forgiving of slight misalignments and good bases that allow excellent lamphouse alignment are still very plentiful for anyone that takes a few minuites to seek them out. What is fewer and farther between are good Xenon lamphouses that posess decent alignmant controls! The Kneisley is one of the worst in that regard. Don't count on the dowsers working for very long either.....

You talk about the industry moving away from glass reflectors and over to metal reflectors and such. According to the President of Optiform it was a move that was made due to lamp explosions and metal being more durable than glass. A customer may have a damaged reflector and a bit less light level after an explosion but he is not off the screen except for a lamp change. In many cases with small xenon lamps it does such little damage and light levels are still just fine. Lets see you TELL HIM that they can't design reflectors any more.... in fact at last years ShoWest he told me that he could easily produce a metal reflector that would give the EXACT same results as Roberts glass reflector. Don't believe me.... then call him and have a chat with him for your self!!

Above all don't think that I doubt there is improvement with Roberts stuff, I'm sure there is improvement but there are other more practical routes one can go and reap major improvements and still keep a customers operating expenses in line.

Mark @ CLACO

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Laurence Hammett
Film Handler

Posts: 16
From: Los Angeles, CA, USA
Registered: Feb 2002

posted 02-10-2005 10:54 PM

The number one house is 565foot throw 40x80 Screen
Scope primary cinelux outdoor f 1.8 4.75 inch Anamorphic Schneider 1/2 reverse ka298r Japanese
Flat Kollmorgen F1.7 4.5 inch cinelux outdoor with Isco Magnacom 65

Don't have the other throws or I would give you those stats as well.

AND we aren't done yet. The projectors need to be centered and plates recut. We might also get better lenses but not necessesarily. So light will go up even further.

I think for all 4 screens we only changed 2 lenses

As for what is amazing - 5 times the light. 500% beats 30% any day

I am no fan of osram either but Osram didn't design this bulb for one and Robert says he hasn't had a bulb explode and if it did the bulb maker pays for it under warranty.

As to other expenses, In drive-ins the grosses DO go up with better presentation. Since I started servicing these drive-ins and fixing the presentation even prior to technolight they are able to stay open 7 days and make a profit week days which wasn't so before. Improving picture can only improve the bottom line. As I understand it the reflector isn't that much more than a metal one and you probably shoud replace the metal ones every year to maintain the light especially with the short arc bulbs. That isn't necessary with glass necessarily.

and as to walk-ins I have seen Robert convert a Christie SLC which had a 4k lamp and max light was 10 fl scope and replace it with a 2k and peg my light meter. His was sitting at 39 before we brought it down. Let's see, Cheaper bulbs which last longer using less electricity with more light, better resolution. and more income due to better presentaion. WHAT Expense??? This was The Winnetka in California where they also have backed off 6k and 6.5k and gone to 4200 and tecnolight. Getting smpte spec, much better resolution and no longer heating up the gates.

As to hi-speed movements it is an extra expense and I can't see anyone getting a spare if they are that scarce. If you have to put in a standard one you have to replace the shutter or risk Ghosting.

Robert actually started out with metal but found that they loose light quickly as they degrade which is untrue of most glass.

We have had one house up for over 6 months with no degrade but in the same venue I replaced the Christie reflectors with good ones and within 6 months the centers had severely degraded Using the short arc LTIs. This isn't the bulb's fault.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 02-10-2005 11:07 PM

quote: Laurence Hammett

I am no fan of osram either but Osram didn't design this bulb for one and Robert says he hasn't had a bulb explode and if it did the bulb maker pays for it under warranty.

Many operator stretch lamp running hours and the risk of explosion is far greater. An exhibitor that is used to getting 3K hours may forget. I have had at least twenty brand new lamps explode within the first 500 operating hours. While they will pay up to a point they won't pay when an exhibitor stretches lamp life.

quote: Laurence Hammett
500% beats 30% any day

When 30% can get you to spec you don't need 500%. The other roughly 400% Roberts may gain is going to waste. Or in theory my customner could light up his screen with a 1600 watt lamp... but those are not made as short gaps.

quote: Laurence Hammett
As to hi-speed movements it is an extra expense and I can't see anyone getting a spare if they are that scarce. If you have to put in a standard one you have to replace the shutter or risk Ghosting.

Actually the high speeds are typically had for about 500.00 which is about the cost of an average 2kw lamp. Thats a really inexpensive improvement. One can also install an electronic pull down projector and get the same 30% results. the customer also still has his regular speed movement and shutter and they can be installed in between reels of film. That customer in Indiana had about 8 fl before the HS movements which is still decent for a "stock" drive in.

quote: Laurence Hammett
Robert actually started out with metal but found that they loose light quickly as they degrade which is untrue of most glass.

Like I said... you call Optiform and have a chat with him. Doubt him in person not on the forum. They make some pretty incredible reflectors......

quote: Laurence Hammett
We have had one house up for over 6 months with no degrade but in the same venue I replaced the Christie reflectors with good ones and within 6 months the centers had severely degraded Using the short arc LTIs. This isn't the bulb's fault.

No, it was probably your exhaust systems fault. INadaquate air flow is the largest cause of premature reflector and lamp failure.

It seems to me that at 5.5 fl you have quite a ways to go. You may also need HS movements a better maintained screen and or new electronic projectors..... And thats 5.5fl with a new lamp....remember, xenon lamps have a decline in output after the first quarter life. That would resonably put you back around 4.7 fl.

Mark @ CLACO

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John Pytlak
Film God

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

posted 02-11-2005 11:05 AM

Perforation wear was one disadvantage of the high speed (5:1) intermittents. With durable modern polyester (Kodak ESTAR) base print film, this is no longer an issue.

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John Hawkinson
Film God

Posts: 2273
From: Cambridge, MA, USA
Registered: Feb 2002

posted 02-11-2005 01:39 PM

Is it possible there is some sort of measurement error going on here? 5.5 fL is pretty dim. But some meters can measure in candela/meter^2 as well. If you have the meter set wrong and misread the decimal point, 55 candela/meter^2 is 16 fL, which is entirely reasonable.

12-16fL is definitely not outdated. It is the standard for Xenon lamps in indoor theatres, and if you go below that, it definitely produces an undesirable image.

--jhawk

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Laurence Hammett
Film Handler

Posts: 16
From: Los Angeles, CA, USA
Registered: Feb 2002

posted 02-11-2005 01:47 PM

The Longer the throw the bigger the picture the less foot lamberts. Look at my earlier post for one of the screens stats. Just looking at footlamberts is a generality. You must take into account the above.

You are not going to get 16 footlamberts aiming at the moon! See what i am getting at.

If you have a smaller screen and shorter throw you will get more light (per square foot). More footlamberts. isn't that obvious?

A lamphouse will put out only so much light. Put the screen closer and smaller and the light is reading more footlamberts. Make the screen bigger and farther away and it reads less foot lamberts.

HOWEVER

ALL the light hits the screen. So 5 or more times the light is still 5 or more times the light.

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John Hawkinson
Film God

Posts: 2273
From: Cambridge, MA, USA
Registered: Feb 2002

posted 02-11-2005 01:52 PM

Actually, the throw has nothing to do with luminance, for any reasonable distance (ignoring atmospheric issues, which can come
up for DI). It's merely a function of the light output and the size of the projected image.

--jhawk

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Richard Fowler
Film God

Posts: 2392
From: Ft. Lauderdale, FL, USA
Registered: Jun 2001

posted 02-11-2005 02:04 PM

Physics 101 [Roll Eyes]

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Mike Babb
Master Film Handler

Posts: 250
From: Norwich UK
Registered: Jul 2002

posted 02-11-2005 03:59 PM

Almost every Technalight install we've been involved with is using Osram 2K W/H and 3K W/H bulbs, basically the same as the theatres had been using before but in many cases we lowered the bulb size for a house. In all cases we increased light.

I'm not aware of any bulb life issues and also am not aware of any differences in reflectors targeted to specific houses. There are two that I've seen, both the same size and shape, one had an extra reflective coating.

You do have to deal with certain cooling issues depending on the lamphouse.

I am not here to sell Robert's product but I will say you should talk to him and check out an install if possible including light readings before and after before dismissing him.

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Chris Hipp
Phenomenal Film Handler

Posts: 1462
From: Mesquite, Tx (east of Dallas)
Registered: Jul 2003

posted 02-11-2005 06:09 PM

quote: Laurence Hammett
If you have a smaller screen and shorter throw you will get more light (per square foot). More footlamberts. isn't that obvious?

A lamphouse will put out only so much light. Put the screen closer and smaller and the light is reading more footlamberts. Make the screen bigger and farther away and it reads less foot lamberts.

I could be wrong here, but isn't a footLambert the measurement of how much light is being reflected off of an object?

5fl on a 10 foot screen is the same as 5fl on a 60 foot screen.

When the screen is bigger and/or farther away, you use a more powerful light source to get the proper amount of light reflecting off of the screen. I am by no means an expert but this is just common sense. In any case, if I could only get a 5 on any size screen, I would cancel the show.

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99

posted 02-11-2005 06:20 PM

quote: Mike Babb
Almost every Technalight install we've been involved with is using Osram 2K W/H and 3K W/H bulbs, basically the same as the theatres had been using before but in many cases we lowered the bulb size for a house. In all cases we increased light.

Was ANYTHING else changed, other than the reflector and xenon? Are you using the SAME lenses as before? The SAME screen as before? Did you change out the port window glass?

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Mike Babb
Master Film Handler

Posts: 250
From: Norwich UK
Registered: Jul 2002

posted 02-11-2005 06:38 PM

All of the installs have involved the reflector kit and an alignment using a special tool. The reflector kit is the reflector, the frame/mounting hardware, and bulb adapters as necessary because the reflector is not always the same distance as the original one. No port glass, no lenses. Same screen. As someone previously said, it is a "system" that includes the reflector and the knowledge of how to install and align it and the lamphouse, head and lenses.

There are additional improvements to be had using lenses (which we haven't done) and adjustable shutter blades which we have experimented on a couple of the installs.

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