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» Film-Tech Forum   » Operations   » Large Format Forum   » MPX Field Flattener Question

   
Author Topic: MPX Field Flattener Question
Mark Lensenmayer
Phenomenal Film Handler

Posts: 1576
From: Upper Arlington, OH
Registered: Sep 1999


 - posted 06-28-2006 06:38 PM      Profile for Mark Lensenmayer   Email Mark Lensenmayer   Send New Private Message       Edit/Delete Post 
For the second time, my "Imax Experience" was plagued by a constant dirty spot on the field flattener. Same spot on the screen--20 seconds on, 20 seconds off.

Is it possible, on an MPX unit to do a better job of cleaning the field flattener during the running of a film, or once dirt gets stuck, it stays until it is cleaned.

I spoke to the management of the Columbus OH Easton AMC 30 about this, and they indicated that they cleaned it after each screening, but there wasn't anything they could do during the running of the picture.

Also to note is that there is not a dedicated operator in the booth with this machine.

Is embedded dirt a design flaw, or is there a solution? That spot on the screen drove me CRAZY during most of the picture.

Note: the dirty spot was even noticed by my wife, who is not nearly as picky about these things as I am!

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Brian Michael Weidemann
Expert cat molester

Posts: 944
From: Costa Mesa, CA United States
Registered: Feb 2004


 - posted 06-28-2006 07:44 PM      Profile for Brian Michael Weidemann   Author's Homepage   Email Brian Michael Weidemann   Send New Private Message       Edit/Delete Post 
I don't know specifically how the MPX field lens cycle is operated, but the specks of dust sticking and not wiping away isn't particularly a design flaw (unless it's actually a nick in the glass, which could appear the same as debris). This happens with the GT on occasion, with a stingy speck. The best we can do is set the auto-wipe to double, and manually set the non-specked part into the aperture. Or, just turn the wipe off. But then, any new specks that could be wiped, won't be.

If they say there's NOTHING they can do except clean it between shows, I'm under the impression the MPX system doesn't have an Adjust screen or a manual field flattener wipe button, then?

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Christopher Seo
Jedi Master Film Handler

Posts: 530
From: Los Angeles, CA
Registered: Jun 99


 - posted 07-01-2006 12:12 AM      Profile for Christopher Seo   Email Christopher Seo   Send New Private Message       Edit/Delete Post 
If the MPX system does not have a way to manually wipe the field flattener, it would be pretty lousy. I suspect the culprit is the lack of a dedicated IMAX projectionist. It's often the case that one half of the field flattener is dirtier than the other, but of course it takes a person actually looking at the screen to figure that out and judge whether to do a single or double wipe and when to do it so as to be minimally obtrusive. Auto-wipe has certainly ruined a few IMAX presentations for me.

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Mark Lensenmayer
Phenomenal Film Handler

Posts: 1576
From: Upper Arlington, OH
Registered: Sep 1999


 - posted 07-01-2006 09:38 AM      Profile for Mark Lensenmayer   Email Mark Lensenmayer   Send New Private Message       Edit/Delete Post 
Christopher, I agree that unattended operation is part of the problem. I believe they are selling the MPX system as being designed to just press the start button and walk away.

The MPX field flattener seems to cycle constantly during the film. The dirt spot is there, then not at about 20-second intervals.

According the the AMC management, once a dirt speck is stuck to the flattener, it can not be taken care of during the running of the film. Unfortunately, both times I've experienced this, the spots have been close to the center of the screen where most action is taking place. It is very hard to miss or ignore.

I'll go back out for ANT BULLY (if it plays there) and see what happens then.

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Gordon McLeod
Film God

Posts: 9435
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 07-01-2006 12:55 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
Sometimes even on a regular flatner a bit of dirt will stick that the wiper bars can't remove so it is there till the flatner can be pulled out at the end of the show and hand cleaned

Originally the field flatner was two seperate peices of glass that one pushed by hand down the apperture block and the old one popped out into a pan under the block and yiou cleaned it by hand. Not a pretty sight when the odd time both popped right through

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Dick Vaughan
Phenomenal Film Handler

Posts: 1032
From: Bradford, West Yorkshire, UK
Registered: Jul 2000


 - posted 07-02-2006 05:41 AM      Profile for Dick Vaughan   Author's Homepage   Email Dick Vaughan   Send New Private Message       Edit/Delete Post 
quote: Gordon McLeod
Originally the field flatner was two seperate peices of glass that one pushed by hand down the apperture block and the old one popped out into a pan under the block and yiou cleaned it by hand. Not a pretty sight when the odd time both popped right through



That used to keep us busy alright. I remember when we were going through a real bad time with a badly photoguarded print of To Fly which was shedding like crazy. We must have changed that field lens at lease 50 times a show! [scream]

The highly sophisticated piece of wood provide to knock the flattener through is now part of the National Cinematography collection here in the Museum. It still carries the inscription "This Side Towards Screen" to stop us getting confused [Big Grin]

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Brian Michael Weidemann
Expert cat molester

Posts: 944
From: Costa Mesa, CA United States
Registered: Feb 2004


 - posted 07-02-2006 06:10 AM      Profile for Brian Michael Weidemann   Author's Homepage   Email Brian Michael Weidemann   Send New Private Message       Edit/Delete Post 
Now how visible on screen was THAT set-up when pushing the new field lens into place?

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Gordon McLeod
Film God

Posts: 9435
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 07-02-2006 10:25 AM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
Actually it wasn't that bad and it did have the advantage that sticky ones could be eliminated as you hand cleaned each segment
It definetly wasn't as intrusive as the IWERKS CDC two peice with the metal seperator is that to get around a patent required

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