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Author Topic: Lamp too bright Phil Ranucci Expert Film Handler Posts: 236 From: Carpinteria,CA, United States Registered: May 2006 posted 01-27-2019 10:08 PM                     Barco DP19 with a 3000 watt lamp. Output is way too high >35 ftlamberts. I can turn the lamp down to the minimum but it's still too hot, over 20ftlm. Running at minimum also can cause flicker issued in the future, a smaller bulb isn't currently an option. Will defocusing the lamp do any damage to the mirror or lightpipe? Thanks  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 01-28-2019 06:16 AM                     (Duplicate, please delete)  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 01-28-2019 06:21 AM                     I recommend you align the lamp to max then pull the cathode back to defocus, counterclockwise on the Z adjuster. Maybe doesn't matter but I have seen damaged integrator parts apparently due to bad lamp alignment... expanding the beam spot rather than going through its minimum should avoid that. If the LSC file was calibrated, the brightness reported will be in the ballpark but far from accurate. If calibrated at 35 it won't be very accurate except close to 35, to get a trustworthy 14 it should be recalibrated at 14.. I have tried installing a lamp as a lower power lamp (4kW as 2kW for a new 20C) to allow lower minimum power and brightness. It worked ok, no flicker, but yours may not like that. Barco sends a max size lamp with new projectors and I didn't have a smaller on at hand. Defocus will shift color a bit, 99.999%+ of people won't notice... but probably out of DCI tolerance. Which no commercial cinema cares about.  |  IP: Logged Leo Enticknap Film God Posts: 7474 From: Loma Linda, CA Registered: Jul 2000 posted 01-28-2019 01:46 PM                        We sometimes encounter this problem installing laser projectors in high end home theaters (for which, obviously, you can't defocus the bulb). The only solution for that is an ND filter in front of the lens.  |  IP: Logged Sean McKinnon Phenomenal Film Handler Posts: 1712 From: Peabody Massachusetts Registered: Sep 2000 posted 01-28-2019 03:26 PM                        This probably wont help you today but there is a smaller aperture you can install on the integrator rod available.  |  IP: Logged Jarod Reddig Jedi Master Film Handler Posts: 513 From: Hays, Ks Registered: Jun 2011 posted 01-28-2019 03:34 PM                     Was going to recommend an ND filter but Leo beat me to it.  |  IP: Logged Peter Hall Master Film Handler Posts: 314 From: London, UK Registered: Dec 2000 posted 01-28-2019 11:53 PM                        Better to place the ND filter (or I agree, an aperture near the ND filter) in the light engine than after the lens. Contrast suffers horribly otherwise  |  IP: Logged German Marin Expert Film Handler Posts: 227 From: Verbania (VB), Italy Registered: Jul 2001 posted 01-29-2019 07:17 AM                     Install a 2000W lamp...  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 01-29-2019 01:33 PM                     Seen DP19 with 1200w lamps installed..  |  IP: Logged

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