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...more signal, less noise!

One of the major challenges in filling a huge screen is getting enough light. A larger 70mm format allows "spreading out" the energy of the lamp, reducing heat-related problems. But even 35mm prints with "Film Done Right" can fill some pretty big screens. I recently went to a 35mm screening at a local IMAX theatre that was quite acceptable for sharpness and screen luminance. They were using a 6K Christie lamp (160 amperes), projecting onto the IMAX 3D (high gain) screen, with about a 70-foot wide scope image. I know that Gordon McLeod takes pride in the quality of the 35mm images he is able to project at the Toronto Ontario Place IMAX theatre.

You certainly won't be able to achieve 16 footlamberts on an 84-foot screen using a 35mm print --- that needs 70mm. But very acceptable results are achievable, and attracting audiences to these 35mm screenings on huge screens.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

What would you say would be the biggest screen possible to achieve 16 footlamberts on with 35mm? 70mm? I know that throw distance and ambient lighting play a role. I don't know what the average thow distance to screen size ratio would be, but I'd be curious as to what the limits may be. But let's assume "best possible" conditions here.

Lots depends upon the efficiency and alignment of the projector (lamphouse, shutter, lens, port glass), and the type of screen used. For 35mm prints, the Strong/Isco-Optic slide rule calculator shows that a 7K lamphouse should be able to light a 24 x 58 foot matte white (gain = 1) screen. Going to a properly curved 1.5 gain screen allows up to a 27 x 65 foot image.

I recall that the North Park in Dallas had plenty of light with 70mm and a much smaller lamp when they showed "Titanic". Brad can give the details. With 70mm having about three times the image area of 35mm scope, you can put much more light on the screen.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Usually a print "color timed" to look best at the 16 footlambert aim specified by SMPTE 196M will be the best choice for theatres that have lower light levels. Making the print less dense will change the tone scale, resulting in smoky shadows, pasty fleshtones, desaturated colors, and highlights without detail.

Taken to an extreme example, if you have a really dim projector, why not make the print so light that it is clear film without an image?

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Oh yes and for Mr.Guttag I might add that according to Paramount we were the only theater to run that film in 70mm that did not scratch it, replace at least one reel or have any damage whatsoever to it...and we did it on a platter! The theaters that ran it changeover damaged their prints to one degree or another.

For more useless history about Northpark, that print of Titanic in 70mm was also the only print ever to be interlocked there. Rather than break it down only to build it right back up or try to move it (which would have been basically impossible) I interlocked it from cinema 1 to cinema 2 after hours for the final week of it's run.

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I went to the downtown Toronto drive-in (the Docks) on a "poor light" call - they were showing "Panic Room" and "Resident Evil". They weren't kidding about the poor light. It was actually funny listening to the sound track and trying to guess what was happening. Occasionally a blob of light was visible on screen. (not kidding)
The light was obviously bad - but playing 2 films that are set almost entirely in the dark at a site plagued by stray light doesn't help.
Passes were given out, some embarrassment resulting from the staff coming to the cars to hand them out... Quite a few cars stayed through both invisible features.
I think I improved the light quite a bit after Panic Room - quite a bright light beam was visible in the fog that rolled in during intermission. None of it seemd to hit the screen though.

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I found out about the place only by accident when passing through Dallas during my move from Georgia to Oklahoma in 1993. I wanted to see "Jurassic Park" in THX-DTS, and Northpark 1-2 wasn't far out of the way. I was impressed when entering the #1 theater, finding it to be every bit as cavernous as the big premiere houses in New York City. The sound quality was the best I have ever heard in a commercial movie theater.

It really sucks out loud that this theater (Texas' Best) is gone.

65mm and 70mm films are still readily available from Kodak:
http://www.kodak.com/US/plugins/acrobat/en/motion/catalog/colorNeg.pdf
http://www.kodak.com/US/plugins/acrobat/en/motion/catalog/print.pdf
http://www.kodak.com/US/plugins/acrobat/en/motion/catalog/inter.pdf

DTS offers a viable 70mm digital sound system.

Labs offer 65mm / 70mm processing and printing.

State-of-the-art 65mm cameras are available.

There are thousands of 35mm/70mm projectors in theatres.

70mm...waiting in the wings to rise again?