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Author Topic: How can I get the perfect screen brightness Yinghong Wu Film Handler Posts: 32 From: Suzhou Jiangsu China Registered: Apr 2012 posted 07-02-2012 09:20 PM                     HI,I am a projectionist who work in a digital cinema.Our cinema have five screen and our projector is Christie CP2000 ZX.I use lamp loc to calibrate the screen brightness.I find the screen brightness is dissatisfied,especially in 3d mode(our 3d mode is dolby 3d).Is there any way to increase our screen brightness.I know the screen brightness is the core in the digital cinema.But I have the limited knowledge about to calibrate the screen brightness.Thx. [/B] [B]Christie CP2000 ZX  |  IP: Logged Chris Slycord Film God Posts: 2986 From: 퍼항시, 경상푹도, South Korea Registered: Mar 2007 posted 07-02-2012 09:53 PM                     Too many unknowns like size of screen (and if it's silver or not; and I know Dolby can be used w/ white but we can't assume it's white), the size/manufacturer/model of the bulb, the brightness you're getting in 2D and 3D. There are probably others I'm forgetting.  |  IP: Logged Yinghong Wu Film Handler Posts: 32 From: Suzhou Jiangsu China Registered: Apr 2012 posted 07-02-2012 10:14 PM                     THX CHRIS，Our four screen is 7X5.25m,One is 12m wide.Our server is DOLBY DSS 100+DSP 100,Our screen is normal screen not silver screen，The bulb is CDXL30.And I don't know how to measure the screen brightness and how to calibrate it.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 07-02-2012 11:23 PM                     If my metric to US measure is correct, the first three screens are 22.75 ft wide and the fourth screen is 39 ft wide. The bigger screen could use a CDXL-40 for 3D.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 07-02-2012 11:25 PM                     No it can't Monte. The ZX cannot handle that bulb. About the only thing you can do is get a higher gain screen (I am assuming you have a standard 1.0 matte white)...or get a projector that is PROPERLY spec'd for that screen size.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 07-02-2012 11:39 PM                     Sorry on that. A BARCO DP2K-20C would definitely fit the bill for that wider screen.  |  IP: Logged Yinghong Wu Film Handler Posts: 32 From: Suzhou Jiangsu China Registered: Apr 2012 posted 07-02-2012 11:52 PM                     THX Monte and Brad,I forget to say the 12m wide's screen use the cp2000sb cdxl 60 bulb silver screen which the screen brightness is ok.Anthor four screen is cp2000zx cdxl30 normal screen which the screen brightness is poor.So I will adopt Brad's suggestion and suggest our boss to replace these four screen with silver screen. I also want to know the right way to measure the screen's brightness thus I can know our cinema's screen brightness is standard.（what tool and method)  |  IP: Logged Chris Slycord Film God Posts: 2986 From: 퍼항시, 경상푹도, South Korea Registered: Mar 2007 posted 07-03-2012 02:08 AM                     The tool is a light meter. It'll measure the luminance, which in the industry is measured in foot-lamberts although in other industries/applications a different unit might be used.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 07-03-2012 03:04 AM                     quote: Yinghong Wu our boss to replace these four screen with silver screen. No, you need a high gain matte WHITE screens for Dolby 3D. It's the other 3D systems that needs the silver screen.  |  IP: Logged Yinghong Wu Film Handler Posts: 32 From: Suzhou Jiangsu China Registered: Apr 2012 posted 07-03-2012 07:09 AM                     Thx Chris and Monte.I got it^-^  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 07-03-2012 10:20 PM                     quote"No, you need a high gain matte WHITE screens for Dolby 3D." there is no such thing as a high gain matte white screen matte is unity gain to a little above high gain non silver screen is pearlescent  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 07-04-2012 06:14 AM                     And certainly, unlike for RealD, a silver-screen is not needed for Dolby-3D, but can give you some extra kick on brightness if the owner or installer did a bad choice on the system layout. Plus, it offers you a choice to upgrade to a usually brighter-than-Dolby polarization 3D system later. - Carsten  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-04-2012 06:56 AM                     As Gord points out...there is no such thing as a "high-gain matte white"...that is like saying it is a large-small. Biggest misconception going around the industry...gain screens make your image brighter...in fact, they make them darker. But wait you say...when I measure a high-gain screen in the center it really does get brighter...well yes...there it gets brighter...everywhere else it gets DARKER and unless all of the action is constrained to the 10-degree area in the middle of the screen...the image will be darker. The only way to really mitigate that is to curve the screen and "accept" the geometric distortions that brings (particularly with the current DCinema lenses...except Schneider). Remember the spec is not just 14-fL in the middle (or 4.5fL for 3D)...it is the middle AND the sides, which need to be not less than 75% of the center (85% for screening rooms)...which can not be achieved on a flat screen with a gain greater than 1.3. Anyone putting in a flat gain screen of 1.4 or greater are out of DCI/SMPTE compliance.  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 07-04-2012 01:16 PM                     Silver screens are EVIL. I cannot understand how come polarized systems are so commonly adopted. Particularly flat silver screens in short throw auditoria are so incredibly bad. How is that possible that people do not realize that you have 14fl on center, but only 3fl on sides?  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 07-05-2012 04:28 PM                     @Marco Where is the Facebook stylee 'like' button?! I have tried this discussion so many times with customers hell bent on ruining their image with a silver screen, all I get is 'the glasses are 50p'  |  IP: Logged

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