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Author Topic: Screens of 80 foot width... Andrew McCrea Jedi Master Film Handler Posts: 645 From: Winnipeg, Manitoba, Canada Registered: Nov 2000 posted 04-19-2006 11:01 PM                        Hello everyone (I'm sort of back). Now, before you get on my back about "screen envy" or "you don't need a screen that big", just think of these questions as hypothetical. How is an 80' screen possible? We know multiplexes use the more sideways rectangle design. We know they like short throws and focal lengths. What kind of throw would you be looking at, and would 600 seats sound reasonable? What xenon wattage would be acceptable and what equipment would be best for the most heat reduction/brightest image, etc.  |  IP: Logged Bobby Henderson "Ask me about Trajan." Posts: 10973 From: Lawton, OK, USA Registered: Apr 2001 posted 04-20-2006 12:11 AM                     quote: Andrew McCrea How is an 80' screen possible? Build a big enough structure and it is possible. Such a screen size is getting into IMAX territory, but it is possible to build -at least from a structural standpoint. quote: Andrew McCrea What kind of throw would you be looking at, and would 600 seats sound reasonable? I couldn't tell you the numbers in terms of distance amount and angle from screen. But I have seen some IMAX theaters project what seemed like a very short throw only over maybe 20 rows of seats to a very oversized screen. 35mm projection is different, naturally. 600 seats is do-able. For a 80' wide screen you could triple that seat count. quote: Andrew McCrea What xenon wattage would be acceptable and what equipment would be best for the most heat reduction/brightest image, etc. This is the real "nut cutting" point. Opinions vary on how much real light ouput is capable from a 35mm lamphouse. Some say as little as 4000 watts. Others may push the total up to 6K or 7K. At either level, you're under budget for a 80' wide screen. You need something on the order of a 10,000 watt lamp to hit 16 foot lamberts at center and 12 foot lamberts at the edge on a 80' wide screen. 70mm projection is the only commercial projection format which can manage that.  |  IP: Logged Thomas Hauerslev Master Film Handler Posts: 451 From: Copenhagen, Denmark Registered: Aug 2000 posted 04-20-2006 01:03 AM                        The worlds largest screen in 1996 - 40 meters (131 feet)  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 04-20-2006 06:00 AM                        80 ft screens do not tolerate fools easily. There is an old letter from Strong showing that lumens above 4000 watts does not increase (with that reflector) unless you go to 70mm. A curved, gain screen is mandatory. Super 80 lamp/JJ projector/Schneider lens, new Hurley Superglo and a "3/4" radius curve on the screen. 16 fl/flat 22 fl/scope 28 fl/70mm Theatre was 950 rocking (big) seats, Cinerama design; angles were PERFECT. Louis  |  IP: Logged Steve Scott Phenomenal Film Handler Posts: 1300 From: Minneapolis, MN Registered: Sep 2000 posted 04-20-2006 10:40 AM                     In Minneapolis there are four 80 ft. (give or take) monsters. Carmike has two of them in their 15-plexes on the north & south sides of the metro, Marcus has their Ultrascreen on the northeast side of St. Paul, and Mullers just finished their "monster screen" at my old home Lakeville. The Carmike machines run 4.5 or 5K bulbs (I think) with basic Christie machines. The results are shaky, scratched & for years the digital sound wouldn't kick over. Sadly, these were the only THX houses too. I haven't seen Lakeville's new monster yet. I'd heard installers were trying to talk up a JJ/cinefocus setup on a 4.5K bulb, but Muller ended up going with an SA brought down from the White Bear Township theatre & some German 6K bulb. A QSC tri-amp crossover was also supposed to be installed behind the screen. The cinefocus setup also went by the wayside. I've heard good things, but I thought they'd drop the 'monster screen' billing from their ads. It's a circus in the suburbs. Marcus has a good setup with a Kinoton machine, not sure of the bulb. Some coworkers of mine saw Serenity there & only complained about the fader being set too low for such a setup. They are THX triamped. Most of these auditoria have a square design, rather than being long & narrow. I don't like these. It gives an IMAX, right up there effect, unless you're toward the back of the house, which just doesn't sit right with me for 35mm.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 04-20-2006 12:52 PM                        To give some idea of the challenge of lighting an 80-foot wide screen properly, with typical 35mm projection efficiencies, a matte white (gain=1) screen would need close to a 15,000 watt lamp to light a 80 X 33.5 foot screen --- of course, if there were such a lamphouse, the 0.825 X 0.690 inch frame of 35mm film would suffer severe heat damage. In practice, a 6K or 7K lamp with an efficient optical system and very efficient heat filter, a water cooled gate, high efficiency lens, and properly curved/tilted high gain screen may barely get you to the low end of the tolerance allowed by standard SMPTE 196M. This is really a job for 70mm film!!!  |  IP: Logged Scott Jentsch Phenomenal Film Handler Posts: 1061 From: New Berlin, WI, USA Registered: Apr 2003 posted 04-20-2006 04:57 PM                        Instead of trying for a single 80' screen, I wish theaters would install more screens that were in the 50'-55' range. There are far too many 26-footers, which are just too small to make the kind of impact going to the movies should provide. Unless that 26-footer is going to be in a nicely-appointed screening room type of environment, it's too small! If your theater is considering installing a monster screen, talk them out of it and tell them to take the money they would spend and upgrade all of their auditoriums. Having one huge one also makes the 26-footers in the other rooms look really tiny...  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 04-20-2006 07:22 PM                     Typical "warehouse" and shopping center building typically have 30 - 31 foot spans between roof support pads = 26 foot screen with an exit door  |  IP: Logged Andrew McCrea Jedi Master Film Handler Posts: 645 From: Winnipeg, Manitoba, Canada Registered: Nov 2000 posted 04-20-2006 09:37 PM                        quote: Scott Jentsch If your theater is considering installing a monster screen, talk them out of it and tell them to take the money they would spend and upgrade all of their auditoriums. This is just personal interest, and what I asked people not to say. I want to know how any theatre could do a 35mm screen in a width of 80'. Kind of with the short throw, etc. that's common in a multiplex. So, what I've gathered: -around 6 or 7kw. -very efficient optical system (what's this?). -very efficient heat filter. -water and air cooled gate. -high efficiency lens (Isco RED Ultra-Star HD PLUS?). -high gain screen (what kind of gain?). -screen properly curved and tilted. Is this a job for Kinoton? I've heard really good things about the steadiness of their projectors and the efficiency/output of their lamphouses. Then, I've also heard Christie mentioned as well, and someone even said something about it in this post.  |  IP: Logged Matthew Bailey Master Film Handler Posts: 461 From: Port Arthur,TX Registered: Sep 2000 posted 04-20-2006 10:19 PM                     A white laser type lamphouse would be ideal for an 80 foot scrren for 35mm but one of the limitations would be image grain. Lasers would produce little or no heat unlike xenon or carbon arcs.  |  IP: Logged Andrew McCrea Jedi Master Film Handler Posts: 645 From: Winnipeg, Manitoba, Canada Registered: Nov 2000 posted 04-20-2006 10:34 PM                        What's a laser type lamphouse?  |  IP: Logged Bobby Henderson "Ask me about Trajan." Posts: 10973 From: Lawton, OK, USA Registered: Apr 2001 posted 04-20-2006 11:10 PM                     Laser Lamphouse??? Is that like a new version of that mirror covered ball they used to put in discos? The big Cine Capris auditorium at Harkins Bricktown 16 in Oklahoma City puts out about as bright an image I've seen 35mm throw onto a giant sized screen. That screen measures 70' across and about 30' in height. A Kinoton projector is used in that booth (probably with a 7000 watt lamp, liquid cooled gate, custom reflector, etc.). I'm sure Harkins has tried hard to get as bright an image onto that screen as possible with 35mm gear. Yet it is just a tad dim for my liking. 5 perf 70mm would do a much better job.  |  IP: Logged Andrew McCrea Jedi Master Film Handler Posts: 645 From: Winnipeg, Manitoba, Canada Registered: Nov 2000 posted 04-20-2006 11:50 PM                        Do they actually make prints that are printed a tad lighter for very large screens, or is this just an industry myth? I'm glad I'm not the only one who doesn't know what that is.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 04-21-2006 12:50 AM                        There's a company called Technilite or something similar who claim to have developed a proprietary bulb/reflector system that increases light output by 1/3 more. It is being installed primarily in light-starved Drive-ins where an 80 foot screen is nothing out of the ordinary. Of course they don't get near the 16fl goal either; in fact, the SMPTE gave up that goal and only aims for 12ftl. Nor do DIs have the advantage of high gain screens (they paint corrigated steel or plywood with white paint -- gain of 1.0 at best). So seeminly if DIs can get viewable pictures on those mamouth screens with whatever new technology this Technilite uses, it is conceivable that an indoor with the advantages it has of controllable ambient light, high gain screen properly curved and tilted, an 80 footer should be do-able. But then again, at what cost in image degradation due to such extreme magnification, especially if you a pushing seats up right up to the screen at the same distances that those shoebox theatres do, in other words, way WAY to close. Theatre designers seem to put those first rows at the same insanely close distance with total disregard to the screen size, matter if it is a 25ft screen or a 60ft screen -- the first rows are almost never at the SMPTE recommended distance, which is supposed to be determined by the screen size, not how close they can get the first row and still let people pass across it. Knocking down the screen size in this hypothetical new build to 65 or 70 feet might move it enough away from the everything-is-super-critical-and-right-on-the-edge-of-scorching-the-film, and into the realm of reasonable. Wouldn't it be better to have a slightly smaller screen with a noticably superior image than a monster screen with a mediocre image?  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 04-21-2006 08:56 AM                        For screening rooms, standard SMPTE 196M specifies the preferred viewing distance is between 2 and 4 times the height of the image. So for a 20 X 48 foot screen, the preferred viewing distance is between 40 and 80 feet from the screen, along the centerline of the theatre. Of course, most theatres have additional seats closer than this distance, and farther than this distance. quote: Andrew McCrea Do they actually make prints that are printed a tad lighter for very large screens, or is this just an industry myth? Yes, in some cases, "Drive-In Prints" have been made for drive-ins or theatres with huge screens, with the print balance a few printer points lighter in density for theatres that are known to fall well below the SMPTE aim of 16 footlamberts. In actuality, you are compromising the image quality of the print --- a light print will have washed out highlights and more "milky" shadows. Fortunately, it is not done frequently, as "dual inventories" of different density prints is hard to manage.  |  IP: Logged

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