This is topic Light bulb changes in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Jan Hackett (Member # 1231) on 05-14-2002, 08:12 PM:
Changing bulbbs in my 5 story high auditorium is almost impossible.
The lamps all have lenses on them, Do I give up and put side lighting on the walls?------------------
Jan Hackett
Theater Operations Manager
Extreme Screen Dynatheater
NM Museum of Natural History Foundation
Posted by Adam Martin (Member # 641) on 05-14-2002, 08:48 PM:
Side wall lighting in large auditoriums is completely ineffective. I've been at two large format theaters with side lighting and one with ceiling and side lights. In order to get enough light to the center of the auditorium, lamp power must be very bright. Which, of course, makes dimmable "atmospheric" lighting pointless. The only effective way to light the middle of a large auditorium is ceiling lighting. This makes either scaffolding or catwalks a necessity. Of course, architects and lighting designers never think past the installation. 
Posted by Bob Brown (Member # 1205) on 05-14-2002, 09:13 PM:
Well you could use a Genie, right Adam? But you need to watch that first step 
Sorry Adam, I could not help that one 
Posted by Adam Martin (Member # 641) on 05-14-2002, 09:39 PM:
Oh, sure, Bob. Bring up the Genie lift story. They are much easier to pick up and move once they're laying on their side facing down the stairs. 
Don't you have four prints of Episide 2 to build?
Posted by Jan Hackett (Member # 1231) on 05-14-2002, 10:20 PM:
Hmm maybe I could rig some kind of a swing.... or is there a 5 story high step ladder scaffolding is to expensive to change a light bulb.....hmmm this is a problem,,,,HELPPPPPPPPPP------------------
Jan Hackett
Theater Operations Manager
Extreme Screen Dynatheater
NM Museum of Natural History Foundation
Posted by Steve Kraus (Member # 476) on 05-14-2002, 10:29 PM:
How did your predecessors change them?
Posted by Jerry Chase (Member # 660) on 05-14-2002, 11:05 PM:
A story is generally 10 ft, so you are talking about 50 feet. The normal MaGill light changing poles max out at about 30 feet. If there are lenses, then the problem is even worse.I think you may be in the ugly situation of finding a company that will give you a contract for changing ALL the lamps out once a year. Ouch.
Posted by Michael Barry (Member # 237) on 05-14-2002, 11:44 PM:
I can't see any other way around it either, unfortunately....but it begs the inevitable question - how many projectionists does it take to change a lightbulb? 
Posted by Frank Angel (Member # 248) on 05-15-2002, 03:55 AM:
Ah, what a difference a few decades makes. In our effort to save the Loew's Kings (Brooklyn NY) from the wrecking ball, we opened it for a special Save the Kings Show. In the course of getting it ready for this event, I had to literally go through every inch of that grand old palace; it became apparent that the designers took everything into consideration. EVERY light was accessable, even the hundreds of 25w bulbs in a double cove 6 stories above the orchestra -- catwalks and crawl spaces were all strategically placed so that every bulb was if not easily changed, certainly changeable with a little effort. The huge chandeliers all had hand winchs that lowered them down to the floor so the bulbs could be replaced and crystal could be cleaned -- image that -- CLEANING theater fixtures. Even the ornamental draperies that hung in the arches could be lowered to the orchestra floor to be vacuumed. It was an amazingly well designed building. Nothing was overlooked in 1929. On the other hand, our small 400 seat Cantor Theatre has no catwalk and every bulb is recessed at angles (making the clamping lamp pole useless). Scoops on the side walls that aim at the ceiling can only be reached by 30ft ladders which are difficult to secure on a sloped orchestra floor. The mask motor is positioned 15 ft on a wall requiring you to wedge a ladder in between two walls only 4 feet apart, making setting the stops a real acrobatic feat. Why this motor was not placed on the floor next to the screen is a mystery. But then again, why the ceiling and walls and columns in a cinema are painted semi-gloss WHITE, is a bigger mystery. This was designed and built in 1994. Nuff said.
Posted by Peter Kerchinsky (Member # 1098) on 05-15-2002, 04:21 AM:
Michael:
Answer to the question, how many projectionists does it takes to change a light bulb?
I've heard, one to hold the bulb and two to rotate the ladder.
Posted by John Anastasio (Member # 607) on 05-15-2002, 06:23 AM:
Make sure that when the lamps are replaced, it's done with the right type...there are long life special bulbs available that are much like the ones used in traffic lights, with heavy-duty filaments. If you never bring them all the way up to 100% (assuming they're dimmable) they should last you at least ten years. I've got lights in my house that were installed in 1985!
Posted by Bill Enos (Member # 440) on 05-15-2002, 08:46 AM:
Today's architects and engineers don't have a lock on stupid though they seem to work harder at it. Our theatre has lots om small bulbs in coves etc. with No access from other than a ladder. The difference is that Frank's Loews was designed by Rapp & Rapp who were master theatre designers and our Byrd was designed by a local architect who did a great job on the structural aspects and sight lines and most things but apparently thought light bulbs lasted forever because any bult that can't be seen directly is difficult to touch much less change. Example is the auditorium dome 80 x 40 ft ringed by colored lights in a cove intended to be reached from the attic. Trouble is the edge of the dome is too close to the ceiling to slide under and the fixtures are too far out to reach and have clipped on roundels so that a bulb stick is out too. The only way we have figured is to have a midget with no fear of heights go under and crawl around the 3 ft wide edge 68 ft above the floor changing bulbs as he goes. Yes I know midget is not p.c. The dimmers on these bulbs were long ago set not to go more that half way up. We believe these bulbs have not been changed in the 74 years the place has been open.
Posted by Geoffrey Weiss (Member # 882) on 05-15-2002, 09:21 AM:
The theatre where I worked was built in 1939, and the architect (a local guy) thoughtfully designed a crawlspace into the ceiling where we could change the auditorium bulbs from above.This is probably a stupid question, but is it possible that there's a forgotten entrance to an attic crawlspace? What vintage is this theatre--if it's five stories tall?
Posted by Jan Hackett (Member # 1231) on 05-15-2002, 10:01 AM:
Well I am glad to know I am not the only one to have this problem caused by poor design. The theatre is 2 1\2 years old. The long life bulbs were installed however many blew out at 6 months. I can reach the back row and the front row of lights but the stadium seating makes it impossible to attempt the middle rows. The question was asked why so high my ceiling? It is a large format auditorium that cost a million bucks to build. You would think one would have designed a way to change bulbs.....! I do not believe there is a catwalk..that would be too easy. The blue prints do not show one. Anyone know where I can get that buglar gear they always use in the movies...????????------------------
Jan Hackett
Theater Operations Manager
Extreme Screen Dynatheater
NM Museum of Natural History Foundation
Posted by Jan Hackett (Member # 1231) on 05-15-2002, 10:04 AM:
OH and I do have an estimate for sccaffolding 4000$ fotr the contractor to set up and change bulbs....OUCH maybe I will just let the all burn out.
Posted by Jon Bartow (Member # 241) on 05-15-2002, 05:31 PM:
The Genie lift people make a "spider" thing for some of their lifts so that you can use their lifts in a stadium seating enviroment. (four adjustable legs and a pltform that the lift sits on) I know they have some lifts at at least 40 feet. You should call around and do some research with different personal lift manufacturers. You might have to put out a few bucks initially, but the savings over say five or ten years could be considerable.
Jonathan
Posted by Gordon Bachlund (Member # 124) on 05-15-2002, 06:14 PM:
Another solution to lowering the voltage minimally to increase incandescent lamp filament life is to use a buck-boost transformer in buck mode. I have found that a 10% decrease in voltage increases lamp life remarkably.In the best of all lighting designs (or retrofits), a single panelboard would feed the lighting circuits only (assuming incandescent fixtures, not a mix of fluorescent or HID), and a properly-sized buck-boost transformer interposed ahead of the panel, wired for a 10% voltage decrease, would permanently limit lamp voltage irrespective of downstream dimmers on individual circuits or groups of circuits.
"Live better electrically?"
Posted by John Pytlak (Member # 331) on 05-16-2002, 07:04 AM:
I checked a General Electric Stage/Studio & Projection Lamp Characteristics Calculator. Here is an example for a tungsten lamp:A lamp rated for 120 volts, operating at 120 volts, will have 100% of its rated life, and 100% of its light output.
If the operating voltage is reduced to 110 volts, the life is 3 times longer, and the light output is reduced to about 70%.
At 100 volts, the life is 10X, and the light output is about 50%.
At 90 volts, the life is 50X, and the light is only 38%.
Boosting the voltage to 130 volts, the life is reduced to 35% of rated life, but light output is increased by a factor of 1.3X.
------------------
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
Web site: http://www.kodak.com/go/motion
Posted by Jerry Chase (Member # 660) on 05-16-2002, 09:09 AM:
The caveat to reducing voltage is that while AVERAGE life may be increased, the weak lamps in the lot will still burn out first, and instead of being replaced at one year they might wait five years for replacement. I'd be seriously inclined to go back to the architect and ask WTF he was smoking when he did the design. The threat of bad publicity, a letter to the A.I.A., and unhappy customers might make him find a solution for you.
Posted by Scott Norwood (Member # 30) on 05-16-2002, 10:03 AM:
As an alternative to reducing the lamp voltage, consider buying 130-volt bulbs for essentially the same result. The color temperature is slightly different, but they will definitely last longer and are cheaper than the traffic-signal bulbs with heavy-duty filaments.
Posted by Craig Hanham (Member # 1010) on 05-16-2002, 08:08 PM:
Look on your blueprints and see how much space between ceiling and roof, or is it one of those retarded architecturally designed barns where the roof is the ceiling?
Anyway back to the point, how much roof space? $4000 will go a fair way to making cat walks between roof trusses.Quote from Rowan Atkinson "If an Architect comes and asks if he can design your bulding, for gods sake be firm F--K OFF!!".
Beware RANT MODE ON
Architects should be left to doing the pretty drawings leave the building design work and construction supervision to the engineers and builders.
If you want a totally useless edifice to fill a city block which cant be used for any pratical purpose by all means call in the architects and their fellow idiots the accountants and .......
Rant Mode OFF
Nuff said