Film-Tech Forum ARCHIVE: Christie Upgrade

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Posted by Robb Johnston (Member # 239) on 02-13-2002, 11:45 PM:

Okay, one of the theatres that I help out at is looking to seriously upgrade their presentation. A brief summary of the situation is this: Their 2 largest houses have throws in excess of 170 feet with large screens. Currently they are running 4000 watt lamps. They are planning on upgrading to 6K lamps. The issue at hand is that one house has a Christie P35C and the other is a Christie P35GP each on a Strong Super Highlight console. Is there any way to adapt the current projectors to handle the heat of 6K.

I have talked with one person who believes that adding a heat filter to the console and a squirrel cage fan monted on the bottom of the projector blowing up through the unit will get us through.

Does anyone have any experince with this sort of setup?

OR are we going to have to replace the projector with something with a water cooled gate?

Posted by Brad Miller (Member # 2) on 02-14-2002, 05:08 AM:

The blower that would normally sit underneath the "exciter" and blow air upwards will be fine. There are many Christie projectors sitting in front of 7000 watt lamphouses. Just do make sure your exhaust can pull enough air out of the lamphouse. In my experience, Strong's minimum CFM will make the lamphouse run a bit on the "toasty" side. I have gotten much better results by increasing the exhaust's air flow (lamphouse) just a bit, resulting in the equipment running cooler and the bulbs lasting longer. Just don't OVERDO it.

Posted by Don Sneed (Member # 955) on 02-14-2002, 05:23 AM:

BRAD....You are correct Sir !!!

Posted by John Pytlak (Member # 331) on 02-14-2002, 08:52 AM:

Here are some links about "Heat Damage":
http://www.kodak.com/US/en/motion/newsletters/reel/fall97/pytlak.shtml
http://www.kodak.com/US/en/motion/newsletters/reel/winter97/projection.shtml

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: 585-477-5325 Cell: 716-781-4036 Fax: 585-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Dave Macaulay (Member # 813) on 02-14-2002, 09:17 AM:

A 4K lamphouse should already have an IR heat filter installed, but if not the 6K will really need it. Without it you will have an extremely hot gate regardless of fans. The Strong one goes in a thin box attached to the front of the console and the snood fits into the box rather than the lamphouse.

Posted by Mark Gulbrandsen (Member # 72) on 02-14-2002, 10:09 AM:

Dave,
The heat filter is an option on all Strong lamphouses. The best heat filters you can get come from UltraFlat and they are also a bit less expensive. They are sold by the square inch.

Robb,
If these folks are really serious about presentation they should trash the P35's and get real projectors to hang on the front of the Super Highlites. I know Brad will back this up...... I'd reccommend a 35/70 JJ, or 35/70mm Simplex as they generally put out a much better 35mm image than either a straight 35mm Simplex or Century head will. Probably the mass of the machine itself contributes to this.
Mark @ GTS

Posted by Pat Moore (Member # 380) on 02-14-2002, 10:56 AM:

FYI -- all Strong Xenon Systems for 4000W and above come with Insertion type Heat Filters as standard equipment.

I have always believed, and have proven in many tests to my satisfaction, that water-cooling the film trap is far superior to air-cooling -- especially in wattage ranges like these.

On the good side, it sounds like your throw is long enough that your lenses are reasonable focal lengths with good depths of field. That will help.

And if I can play salesman a bit, take a good look at ISCO's Plus Lenses. I've seen some great light improvement from simply changing to this new lens technology. More light with better distribution, without increasing power and heat at the aperture using more expensive, shorter warranty lamps. Seems like a pretty good deal...

Pat

Posted by Robb Johnston (Member # 239) on 02-14-2002, 06:23 PM:

Pat, one of the houses does have the heat filter on it, but the other does not. What would the part number be for the heat filter assembly, and also, for the filter itself. IT would not suprise me if the exising filter needs some work. The head projectionist for the site didn't even notice that it was there.

If it is in bad taste to post part numbers, by all means email them to me

Posted by Dave Macaulay (Member # 813) on 02-14-2002, 06:35 PM:

Yes, Strong systems 4kW+ come with the heat filter. That doesn't guarantee that there is no Strong console running 4kW without the filter.
Used equipment gets upgraded. Lamps explode. People manage to break them other ways.
The film trap would be quite hot with no filter, but that might be accepted as normal in their booth. With 6kW it will be way too hot.
With 6kW I would want a water cooled gate in a Simplex (actually 4kW too), however I don't have much Christie experience and the aircooling may be better on them.
Our policy with Simplex is to have water cooling on 4kW and up.

Posted by Pat Moore (Member # 380) on 02-15-2002, 07:35 AM:

Hi Robb; There's a complete Heat Filter Kit (40938) that includes the mounting bracket and hardware that goes onto the front of the console's snood. If the bracket is already there (same as used with the 70mm Beam Spreader ass'ly), maybe you're missing the "Heat Filter & Ring Ass'ly" (40939). The heat filter glass is available as well, but I don't remember the number offhand.

Pat

Posted by Greg Pauley (Member # 503) on 02-15-2002, 09:17 AM:

Robb:
You may want to wait before making a decision on moving up to 6k bulb until after showwest. If you attend the show you'll want to stop by the NCS booth to see what's new. At the Keith Albee Theatre in Huntington, WV we are running a 3000wt on a 46' screen and we're getting 24'fl on scope and 18 fl on flat. I might be able to talk more later.

Posted by John Pytlak (Member # 331) on 02-15-2002, 11:43 AM:

Greg Pauley said: "we are running a 3000wt on a 46' screen and we're getting 24'fl on scope and 18 fl on flat."

Don't forget that Standard SMPTE 196M allows between 12 and 22 footlamberts for theatres, with an aim of 16 footlamberts.

I certainly prefer bright pictures to dim ones, but you may find the flicker is objectionable at 24 footlamberts, unless you are using a 3-blade shutter.

A 3000 watt lamp should certainly be able to achieve 16 footlamberts aim luminance on a 46 foot wide, moderate gain curved screen. But to get 24 footlamberts, you must have a few tricks up your sleeve --- do you care to share them here?

Posted by Greg Pauley (Member # 503) on 02-15-2002, 03:34 PM:

John:
My lens and picture slide computer show the bulb size for a 46 wide flat-matte screen to between a 4000 and 5000wt bulb. I was running a 4000wt before and had problems getting above 13fl. The 24fl reading was made running the bulb at around max at 100amp, but we didn't see any problem with flicker at 24fl. We ended up turning down the amperage to 90 to get below 22fl. Seems funny to talk about turning down the brightness on the screen using a 3000wt bulb on a flat-matte 46'screen. I'm not involved with any of the improvement of the light except for paying the bill. I might be able to give more details later. I hate to be a tease, but I really can't discuss any details at this time.

Posted by Gordon McLeod (Member # 33) on 02-15-2002, 04:22 PM:

To get that mcuh light on a matte screen usually indicates a bit of a hot spot
The only lamphouse"s I have scene that in the reel world are that efficient are the Ernamann and the Kinoton

Posted by Greg Pauley (Member # 503) on 02-15-2002, 04:48 PM:

Gordon:

The lamphouse at the Keith is a Xenex II and the light is evenly spread with about a 4 to 5fl drop on the sides. If I'm not given permission to give some details before Showwest, make sure you stop by the NCS booth and see for yourself.