All the comments are "right on". Kodak's "Enhanced Theatrical Experience" (ETE) team has been doing some great work in quantifying the factors that degrade projection performance, and has shown some of the work publicly (e.g., last year's ITEA Seminar, this year's SMPTE Conference). Earlier Kodak research by Dr. Fred Kolb and Paul Preo, and work by Willie Borberg, Glenn Berggren, and others have been published in the SMPTE Journal.

The name of the game is getting as much light as possible on the screen, while keeping the film frame cool and stationary. As Pat notes, effective heat filters, gate design, and directed air flow are useful in doing this. Although water cooled gates are primarily for operator comfort, the cooler rails and trap may reduce sticking of the film to hot surfaces, improving steadiness and reducing buckle. Pat is also very correct in noting the effect of lens design, especially choice of f-stop, in compensating for the film flutter that does occur. IMHO, filling screens up to 20 x 48 feet with great 35mm film images is made easy by today's lamphouse, projector, lens and screen technology. Bigger images than this need more care to "do film right". AFAIC, any screen over 25 feet high deserves the quality only 70mm prints can provide. For more information:
http://www.kodak.com/US/en/motion/newsletters/reel/february97/pytlak.shtml (Scope 1.5X)
http://www.kodak.com/US/en/motion/newsletters/reel/fall97/pytlak.shtml (heat damage)
http://www.kodak.com/US/en/motion/newsletters/reel/spring98/pointers.shtml (screen luminance)
http://www.kodak.com/US/en/motion/newsletters/reel/december98/pppp.shtml (70mm part 1)
http://www.kodak.com/US/en/motion/newsletters/reel/march99/pytlak.shtml (70mm part 2)

 |  IP: Logged

How much could I expect to pay for both? (my orginal post for water cooled said $300) An extra $100?

Should I really go with both?

How about such a filter for the blower? Mark stated that the unit would fill with crud due to lack of filter. In a drive-in, I would be a little more concerned with this issue, than in a hardtop.

To John P: Has Kodak's Screencheck certified an outdoor screen? (I know there would be a whole new set of rules in regaurds to such) Would that be something to consider? We ozoners want a good projected image for our customers too.

--Chris

BTW, at the drive-in I worked at, we pulled 120 amperes using 11mm rotating positive HI carbons to light a 42 x 100 foot screen. Really appreciated those Century projectors having water cooled gates! The Ashcraft lamphouses had dichroic coated glass reflectors (Bal-Cor made by Bausch and Lomb?) to reduce the heat on the film. We never measured screen luminance, but my "calibrated eyeballs" estimate that we probably got about 4 footlamberts on a freshly painted screen. (Another area the ScreenCheck spec of 16 footlamberts would need to be modified).

------------------
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

 |  IP: Logged

 |  IP: Logged

I used several different kinds of water tanks/pumps that were supplied for our Simplexs. One was a blue plastic tank with a submersible pump. The other was a steel tank with a motor on the outside (on top) and a shaft down to a brass impeller below.

The blue plastic tank design sealed completely (the lid was locked down by a round steel ring.) This prevented water from evaporating. However, we went through *many* submersible pumps- they'd only last about a year; then die.

The steel tank (it's painted the same as the projector) does not have a sealed top. Also, there is a hole on the side to prevent overfilling it. Water evaporates out of it, so you have to keep filling it every month or so.

You probably know this, but don't forget to only use distilled water and add some kind of anti-freeze in case it gets too cold.

 |  IP: Logged

The best way though is filtered city water...always cold.

Steve

Heh. Never been to South Florida, eh?
Somedays I can p... colder than the water here.

We had Noreclos with water cooled gates at one theatre. We replaced the metal cans with plastic trash barrels when those rusted out, and when the circulator motor got noisy we junked the water cooling.

Yeah but do you Florida types clean the "chads" out of your splicers?

Steve

As far as antifreeze. Use the minimum amount. Actually, antifreeze isn't so much for the "antifreeze" qualities but more of a preservative. Keeps the water from getting scummy. (as quicly)

I've been using 1 gallon of antifreeze to 5 gallons of water. You could probably get away with 6 gallons or more. Just enough to make the water green. That's all.