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Topic: Contrast issues nec3240s

Frank Cox
Film God

Posts: 2234
From: Melville Saskatchewan Canada
Registered: Apr 2011

posted 06-04-2018 01:00 PM

I'm wondering what happened here. Does this chap have a vastly overpowered/oversized projector for his auditorium and screen size? That seems like a good way to spend a lot more money for equipment and electricity to run it, and end up with a lesser result in terms of the picture that people are watching on the screen.

You wouldn't use a John Deere tractor to tow a kids red wagon. Why would you do this either?

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Sascha F. Roll
Expert Film Handler

Posts: 140
From: Berlin, Berlin / Germany
Registered: Sep 2015

posted 06-04-2018 01:54 PM

Well as he stated in his first post they don't do 3D "any more" so I guess the projector initially was correctly spec'd for 3D on his 16m (52 ft) wide screen as they must have used shutter or Dolby 3D with less-than-stellar light efficiency.

I'm still a bit surprised about the numbers quoted earlier (hitting 20 fL with a 4,5 kW lamp on a 50 ft screen), especially if you consider that he already has the Iris in place and (probably?) a matte white screen.
I guess those numbers (20 fL Peak White) are for Flat only?

Taking into consideration that NEC is not the most light-efficient DLP projector out there a 4,5 KW lamp with the Iris seems like the right choice for the given screen dimensions to me. Next question would be which lamp is he using? Were the 20 fL Peak White measured with a brand new bulb? Talk about aging lamp, luminance dropoff...

Lots of variables here. We have a few NEC 3240 in Berlin (as well as Barco DP4K 32B and Kinoton DCP30 LX II 4K) and they _ALL_ have shitty picture with poor contrast - so nothing that is really surprising me. DoPs and / or directors are also constantly complaining about the poor image quality in some "premiere" venues - but usually the "other" choice for their event would be the multiplex across the street with a 2.4 gain silver screen...

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Fernando Caldeira
Film Handler

Posts: 45
From: Lisbon , Portugal
Registered: Mar 2010

posted 06-06-2018 07:05 AM

It´s a Matte white screen.

The bulb is 4.5Kw. The numbers are for flat only, yes.

We use Ushio DXL-45 lamps.

Cheers
Fernando

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Sean McKinnon
Phenomenal Film Handler

Posts: 1712
From: Peabody Massachusetts
Registered: Sep 2000

posted 06-06-2018 10:26 AM

Fwiw, I have found that they do help with contrast because you have less stray light being reflected.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 06-06-2018 04:36 PM

You find you have stray light reflected in a darkened theatre? (aside from the Exit sign, I suppose). Perhaps some ill designed step lights pointing at the screen?

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