Film-Tech Forum ARCHIVE: Screen Gains and contrast

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Topic: Screen Gains and contrast

Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007

posted 01-31-2014 07:10 PM

Yes Carsten,

I have replied today.

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Christopher Woollard
Film Handler

Posts: 40
From: Dovercourt, Harwich, England
Registered: May 2004

posted 02-08-2014 06:39 AM

The new NEC laser digital cinema projectors are about to launch. The prototype has vastly improved contrast over xenon illumination. Possibly wait until you can review this technology. The others will follow in short course. We had a demo of laser projection over here in the UK at Pinewood, stunning but likely to be very expensive. I have exactly the same problem with digital projectors. You could talk with Harkness regarding their high contrast grey screen. They do provide screen samples.

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Alan Gouger
Jedi Master Film Handler

Posts: 501
From: Bradenton, FL, USA
Registered: Jul 2000

posted 02-08-2014 10:57 AM

Christopher would that be the smaller unit similar to the NC900C or the full size projector. Thank you.

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Christopher Woollard
Film Handler

Posts: 40
From: Dovercourt, Harwich, England
Registered: May 2004

posted 02-08-2014 12:37 PM

Hello Alan
The projector we saw was a prototype. Very small producing superb quality images.
The projector was even smaller than the NC900C.
We were informed the first commercial laser projector from NEC would be the NC1100L, suitable for up to 11m screens (1.8 gain) with the same media block as the NC900C. No one mentioned a price but the launch is due for March. I hope the BKSTS can do an event for it as everyone will be interested.

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Bajsic Bojan
Expert Film Handler

Posts: 190
From: Ljubljana, Si, Eu
Registered: Aug 2008

posted 02-08-2014 06:08 PM

while on the topic of screen gain.

For 3D polarization purposes, should one look at the screen gain primarily or the extinction ratio? They seem to be correlated and the later is also lower, as apparently no silver screen is 100% polarization-proof. Does this play an effect on the measured brightness of the reflected light through passive (realD) glasses and how much.

Does it effect contrast also? I cannot find anything useful on this subject here or elsewhere on the net.

Thanks

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Carsten Kurz
Film God

Posts: 4340
From: Cologne, NRW, Germany
Registered: Aug 2009

posted 02-08-2014 07:44 PM

quote: Christopher Woollard
vastly improved contrast

If so, wondering why NEC is advertizing a mediocre 1600:1 for it?

http://www.necdisplay.com/documents/PressReleases/NC1100L_PressRelease.pdf

This is an S2k machine, and it seems the light engine is not optimized for laser illumination. As such, the S2k chipset seems to be the limiting factor.

- Carsten

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Dave Macaulay
Film God

Posts: 2321
From: Toronto, Canada
Registered: Apr 2001

posted 02-08-2014 08:41 PM

Screen gain on a silver screen for 3D is best decided with the auditorium and screen/projector geometry in mind. Higher gain means more directivity and more hotspotting. For a "shoebox" cinema with the projector close to the screen centre a higher gain screen is generally good. For a stadium cinema or larger conventional room, higher gain will result in a worse hotspot and poor image brightness outside a triangle with the point at front row centre. A curved screen will help in a wide house and tilting the screen appropriately helps where the projection point is far above screen centre. In my opinion lower gain looks better, but economically the brighter projector needed might kill that deal. The laser systems have been touted as brighter and potentially ideal for larger 3D venues; although the TCO difference is not clear as of yet you may want to think about laser. Although there are other issues (such as initial cost, glasses loss, and the need for a cleaning system + procedures), any non-polarized 3D system gives a superior image (again, just my opinion).
As far as extinction ratio - no system is perfect and I haven't seen a huge difference specified between systems. With polarized systems the screen deteriorates over time and specs will be for a best case screen. The Dolby and various shutter glass systems don't have that degradation of extinction ratio with screen aging. Every screen, 2D or 3D, loses brightness as it ages and gets dirty. Other than very careful dust removal I don't believe there is any way to clean a silver screen successfully. Matte screens can be cleaned but results are unpredictable and a new sheet is usually the better solution - and matte screens are much cheaper that silver to replace.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 02-10-2014 02:03 PM

I found out last week that the NC-1100 has a projected list price of around 45K USD.

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