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Topic: Substitute Lamphouse

Al Chaney
Film Handler

Posts: 33
From: Madison, AL
Registered: Mar 2001

posted 03-15-2001 02:36 PM

Can some tell me is there a substitute
or replacement lamphouse (110 volt) I can use on my 35mm Century C projector. Can I use a slide projector or incandecent lamp as a replacament?

al wk:916-341-6233

Thank you forum members

John Pytlak
Film God

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

posted 03-15-2001 03:58 PM

The optics of a 35mm projector are designed to have the film illuminated by a cone of light formed by an eliptical reflector that focuses the light of a carbon or xenon arc lamp just in front of the aperture. Since you would have to design a reflector for a standard tungsten lamp, your idea of using a slide projector to focus light on the film at the aperture should work for a small screen. An integral halogen lamp / reflector (e.g., FXL lamp) used in some AV projectors might work, but you may have difficulty getting it close enough to the film plane due to the shutter.
Best advice is to look for a used arc lamphouse, since a 5400K source is specified by standard SMPTE 196M anyway.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Paul G. Thompson
The Weenie Man

Posts: 4718
From: Mount Vernon WA USA
Registered: Nov 2000

posted 03-15-2001 06:18 PM

Years ago, ORC 1000 integrated xenon lamphouse was built that works with 35mm applications. It was small, compact, and self-contained. It simply plugged into a 120 volt receptacle. I am sure you can still find some around somewhere. However, be prepared to pay a hefty price for them. Last I heard, they go for about $1,000 or so.

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 03-15-2001 09:09 PM

Hi Al,
Any relation to Dick? What type of setup is this home, or theatre? At home you can get away with murder if you want to but as JOhn says the correct color temperature also has allot to do with it.
Mark @ GTS

Jeff Stricker
Master Film Handler

Posts: 481
From: Calumet, Mi USA
Registered: Nov 1999

posted 03-16-2001 07:55 AM

I have built a homebrew lamphouse using ENX 360 watt quartz halogen lamp and a condenser lens liberated from a photo enlarger. I had to do a bit of experimenting to determine the distance between lamp and lens : lens and film plane, but when finished I got great results (of course this is a home set up and, yes, the color temp. is off, but....). Also you will need a muffin fan to cool the lamp. This who effort set me back about $20.

Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99

posted 03-16-2001 09:12 AM

Couldn't the color temperature be corrected with a gel on the port glass? Maybe John P. or someone else could post the exact number. I'm guessing that you want something like an 80A filter/gel, which is normally used on a camera when shooting film balanced for daylight indoors. You lose something like 2/3 of a stop, but it balances the light more toward the blue end of the spectrum (like xenon).

John Pytlak
Film God

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

posted 03-16-2001 11:08 AM

To convert 3200K to 5500K, you would use a Wratten 80A or equivalent filter. But the light loss is almost 2 stops, so it will much harder to get a bright image.

If you can't find an arc light source for home use, I'd just use the tungsten-halogen lamp and settle for 3200K on the screen. In a darkened theatre, the eyes adapt quickly, and a slightly yellow highlight is preferable to having a dim picture.

Al Chaney
Film Handler

Posts: 33
From: Madison, AL
Registered: Mar 2001

posted 03-16-2001 03:05 PM

Thank you Forum Member for your help. I am running a home screening room (20'x 40'), curently running video. I am a Newbie and don't want to invest a lot of money until l learn more about the equipment. I have looked into the ORC 1000 and they are priced at $1200.00 as Paul stated. However, as mark mentioned I do want to get away with murder on the less than perfect projector while I am learning. I do have an old Holmes 8, with a lamphouse on it. Can the Holmes lamp house be used with my Century C projector. I welcome your comments and sugesstions for a substitute lamphouse.

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