Film-Tech Forum ARCHIVE: Projection for large houses (70-80' w)?

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Posted by Bob Jones (Member # 1756) on 08-23-2004, 03:47 AM:

Larger screens opening everyday. Any of you who are operating on screens in the 70-80' width -- what types of projection systems (lamphouses, lenses) are you finding to be adequate? I'm seeing a lot of the Kinoton FP-50Es with the 7000 watt lamphouse. Is there anything larger that is working well with 35mm? Thanks. --Bob

Posted by John Pytlak (Member # 331) on 08-23-2004, 05:39 AM:

That's about as much power as I've heard being used for a 35mm print (I've heard rumors of up to 10K lamps being used). Of course, lamp power is only one factor on how much light you can get. Lamphouse efficiency, alignment, lens choice, port glass, and screen gain (and curvature) all enter into the equation. At those power levels, good heat (IR) filtration and water cooled gates are mandatory.

Posted by Mike Babb (Member # 1379) on 08-23-2004, 09:19 AM:

http://www.robertfilm.com/english.html

You might check out these guys. They specialize in light level efficiency and large screens. If you bounce around on Film Tech you'll find a topic about it. I haven't seen it myself but there's a Xetron/Technalight system for new installations now.

Posted by Jack Ondracek (Member # 1466) on 08-23-2004, 10:56 AM:

Thre are a couple of drive-ins down here that are using it now. The conditions probably don't make for a very good estimate how it would work in an indoor venue, but (so far) the drive-in people seem to be happy. However they rate it, they appear to like what they're getting out of a 4kW installation.

I'm waiting to see if time has an effect on performance of the Technalight system, since nobody's commented on the life of those 4200 watt reduced-gap bulbs. I also haven't seen any comparison regarding heat. The filters & reflector notwithstanding, if the light level hitting the film compares to that of a conventional 7kW install, is it likely that the infrared number would also be comparable?

Could you put those 4200 watt bulbs in your present lamphouses and get that same kind of performance increase?

Posted by Bob Jones (Member # 1756) on 08-24-2004, 02:08 AM:

I have heard rumors too of a 10K watt lamphouse -- but have not found anyone who is familiar with it -- or how the 35mm stock holds up.

Posted by Rick Hunter (Member # 1606) on 08-24-2004, 03:28 AM:

The below quote is from David Kilderry..

The picture & sound in this room are very good.
Good, bright steady picture with very clean sound.

Rick

quote:

Expert Film Handler

Posts: 210
From: Melbourne Australia
Registered: Sep 1999

posted 12-27-2002 06:12 PM CT (US) (11:12 AM Local)
--------------------------------------------------------------------------------
The new Village Knox Multiplex Cinema 1 in Melbourne Australia is called V-Max. It has a screen width of 28.5 meters on scope. It runs a new Cinemeccanica Victoria 8 projector and console and utilises a 10,000 watt xenon lamp. Twelve footlamberts is measured on scope with a slight fall with w/s. Current is at 195 amps and the head is water cooled with refrigerated cooling to be added. The theatre seats 750 and is 70mm equipped - bring on the prints.

To date there has been no evidence of dye migration or emulsion void. The jitter and weave measured is low considering the picture size and the Victoria 8 is quiet and smooth (especially when comparing to Vic 5's). The lamp is changed every 4 weeks to maintain safety, quality and light levels. It utilises a Cinemeccanica platter, but a back-up projector is in place. Sound is Dolby Digital with a CP 650; amps and monitor are QSC. Speakers are Krix with the screen from Harkness Hall. Automation is Pennywise CA 100 with CA link.

To date every session has been full since LOTR Two Towers commenced.

David Kilderry

Posted by Andrew Jefferson (Member # 2565) on 08-24-2004, 03:32 AM:

We have two 65' screens, both with 3600w Xenon, that's using a Xebex Supersol 6kw Lamphouse on the back of a Vic 5, using Gold Isco lenses, optical glass, and a hi-gain perlux II Harkness screen...

Posted by Steve Guttag (Member # 268) on 08-24-2004, 06:39 AM:

If curved properly with the appropriate gain screen, you can get 16fL with a 7KW (and possibly a 6KW) lamp on an 80-foot wide screen with even light that will meet SMPTE specs.

Note, Schneider and ISCO now offer lenses that dip down to f/1.7 (the more things change, the more they stay the same). For ISCO they are special order versions of the Ultra Star PLUS and for Schneider they are the Cinelux-Premiers with a variable iris to exactly match light levels between formats (they go up to f/4 for maximum depth of focus).

Steve