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Author Topic: NEC 2000C Moire Pattern - Possible Causes? Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 01-06-2015 07:58 PM                     I guess they could use laser cutting for the perforations nowadays, but it would probably be more expensive than ordinary mechanical perforating. The random pattern should be not such a big problem. There is a lot of 'classic' theory available, e.g. http://en.wikipedia.org/wiki/Dither - Carsten  |  IP: Logged Marcel Birgelen Film God Posts: 3357 From: Maastricht, Limburg, Netherlands Registered: Feb 2012 posted 01-07-2015 04:11 AM                     Laser cutting sounds like a plausible solution, but wouldn't laser cutting create burned edges around the perforations?  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 01-07-2015 04:30 AM                     No, laser cutting can produce very clean edges, surprisingly clean. BTW - we have a wall covering in our old cinema made from PVC in the fifties. It has about the same perforation pattern as our screen. They could do these perfs perfectly even back then. I guess all 'roller-type' perforaters would produce visible bands when using random patterns. Heck, the best way to do it is to hang an unperforated screen, then switch on your laser projector and play a 4k dither_perf DCP ;-) - Carsten  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 01-07-2015 01:29 PM                     Some screen manufacturers have already modified their perf pattern for DLPee. Severtson is one of them. I have always had way less moire on a Severtson screen then on any other surface. Mark  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 01-08-2015 10:12 AM                     Any info in how far their perforation differs? Is it more random, or applied at an angle? Wondering wether you could actually hang any 'straight' perf screen slightly angled and then let the masking take care of it? You loose some screen estate, but then this standard screen material is far less costly than those optimized versions. Wondering how much of an angle is needed to reduce moire noticeably? - Carsten  |  IP: Logged

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