my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Community   » Film-Yak   » Digital Projectors at ShoWest convention (Page 2)

This topic comprises 2 pages: 1  2

Author Topic: Digital Projectors at ShoWest convention Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-19-2007 08:09 AM                     quote: Darryl Spicer So basically you have cool light hitting the light engine and I would suspect that fading would not occur since the damaging light would not be there. Cool light.... Yea, thats why there is a closed loop cooling system with a water pump moving glycol though each 2K DC projector's light engine. Actually the fading of dhicroics even occurs in photographic printing machines over time. Now those machines DO USE a cool light source!! Mark  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 03-19-2007 09:02 AM                    Just quoting what the Christie people told me. I was wondering the same thing. If it's cool light why all the hoses going to the light engine. But all of the ultraviolet light is removed before the light hits the light engine so the damaging light is suposed to be gone hence the brighter picture. That's what Christie claims anyway.  |  IP: Logged Tristan Lane Master Film Handler Posts: 444 From: Nampa, Idaho Registered: Feb 2002 posted 03-19-2007 09:56 PM                     Mark - I think that the reason the chips are cooled they way they are is because they are a mechanical device, and to hopefully reduce further stress on the prism. I doubt that dichroics are as sensitive as DMD's, but fading may still happen over time, even with the reduced UV. It would be prudent to mention that you can run pure white light @ 20 FL through the lens all day long without cracking an element due to the reduced IR and UV. (not that this wouldn't affect the coatings over time) I still believe (and hope) that the dichroics will outlast the chip and asociated technology. Look at some of the quality cold reflectors that still look great after 10-15 years of abuse. Proper cooling goes a long way.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-19-2007 10:06 PM                     Tristian, It would be interesting to k now exactly how hot the light engine gets. A light engine failed here in SLC in a big hurry when the cooling system failed to pump. Sure the silicon on the imagers is MORE sensitive to heat but I've seen dichroic fade occur even in photo lab machines that are far more expensive to buy and that use relatively low light levels. Many of the filters in the DC Projectors are multi coated to create a specific light bandpass... not sure how the life of them will fare but it will be interesting to measure over years and see color space drifts much. Mark  |  IP: Logged Peter Castle Expert Film Handler Posts: 220 From: Wollongong University, NSW ,Australia Registered: Oct 2003 posted 03-20-2007 06:09 AM                     Did anyone see the Dolby 3D demo at Showest? I presume this was of the German 'sort of' anaglyph system.  |  IP: Logged Tristan Lane Master Film Handler Posts: 444 From: Nampa, Idaho Registered: Feb 2002 posted 03-20-2007 01:03 PM                     I don't think that the dolby system could be considered anaglyph, or "sort of". I didn't get to see the presentation, but only heard minimal complaints about the design of the glasses. It uses a rotating dichroic filter at the integrator rod to modify the light for each eye. From what I gather, the optics used in the glasses are much more expensive compared to cheap one-time-use polarized glasses, and therefore will be sanitized and re-used after each show. Color correction is performed in the dolby show player, and I was told there weren't any issues with the color on screen. I hoped to have a chance to see the presentation, but didn't make it. I think one benefit of this system is that rather than polarizing the projected image after the lens (like IMAX and RealD) you are "polarizing"[sic] the light source entering the light engine. I'm unsure if there is any benefit to this method, but it makes sense. Mark, I'll check on that for you. There's temp sensors on two of the DMD's as well as the prism. I'm sure it also depends on the size of lamp the projector is running.  |  IP: Logged Bobby Henderson "Ask me about Trajan." Posts: 10973 From: Lawton, OK, USA Registered: Apr 2001 posted 03-20-2007 01:17 PM                     quote: Tristan Lane It uses a rotating dichroic filter at the integrator rod to modify the light for each eye. From what I gather, the optics used in the glasses are much more expensive compared to cheap one-time-use polarized glasses, and therefore will be sanitized and re-used after each show. If this is true, that could be a bad knock against Dolby's 3D system. If the glasses are expensive, then they'll be a costly item to maintain and replace. Count on customers breaking lots of them. This is one reason why I rarely, if ever, see any IMAX 3D theaters using the laser controlled LCD 3D glasses and PSE headsets anymore. It's far cheaper to use cheap, plastic ones with basic polarized lenses. The other problem is the sanitation issue. The health departments in many states would probably mandate movie theaters have something along the lines of a heavy duty dish washing system similar to those used in restaurants to clean and sanitize the 3D glasses. Some theaters wouldn't have any space to install such equipment. That factor is the principal reason why RealD shows just give away the glasses to the customers.  |  IP: Logged David Stambaugh Film God Posts: 4021 From: Eugene, Oregon Registered: Jan 2002 posted 03-20-2007 01:51 PM                        quote: Bobby Henderson RealD shows just give away the glasses Cinemark here charges $1.50 premium, ostensibly to cover the cost of the glasses. However I've been told they don't give you a credit if you bring your own recycled glasses (haven't tried that myself yet). Will find out if the new Regal does the same thing on pricing for 3D shows when "Meet The Robinsons" opens (playing in 3D at both Cinemark and Regal).  |  IP: Logged Ron Curran Jedi Master Film Handler Posts: 504 From: Springwood NSW Australia Registered: Feb 2006 posted 03-20-2007 06:34 PM                        Bobby, we have a State-approved commercial dishwasher (not cheap) because we serve coffee and tea in china cups ans saucers. I can't see how it would handle 150+ pairs of glasses. Also, they wash at extremely high temperature so plastic glasses wouldn't stand up to too many treatments.  |  IP: Logged Bobby Henderson "Ask me about Trajan." Posts: 10973 From: Lawton, OK, USA Registered: Apr 2001 posted 03-20-2007 06:41 PM                     I assume the more advanced glasses Dolby sells would have to be dishwasher safe. I, too, kind of wondered if the price premium I've seen on RealD shows has been to cover the cost of those glasses. It could be that. Or it could be those royalty fees RealD charges. Or a bit of both.  |  IP: Logged Dustin Mitchell Phenomenal Film Handler Posts: 1865 From: Mondovi, WI, USA Registered: Mar 2000 posted 03-20-2007 08:22 PM                     For the Meet the Robinsons feature at least the customers are allowed to keep the glasses. In NATO's former magazine, 'In Focus' there was an article about the various 3D systems last years. One thing it mentioned was special washers for the glasses if they were to be kept by the cinema.  |  IP: Logged Paul Konen Jedi Master Film Handler Posts: 981 From: Frisco, TX. (North of Dallas) Registered: Jun 99 posted 03-20-2007 08:29 PM                     The DMD's get pretty hot. The TPC will show you the temps of each one.  |  IP: Logged Tristan Lane Master Film Handler Posts: 444 From: Nampa, Idaho Registered: Feb 2002 posted 03-22-2007 01:10 AM                     Not that hot, I checked on this today on houses running 2K to 4.5K lamps. The DMD temperatures ranged from 80 to 90 degrees F. The Prism was 85 - 90 degrees F. This is near the tail end of the shows. Believe it or not, the hottest part was not even in the light path, it was a module used to monitor temperature and interlocks, and to control fan speed. It seems the cooling system is pretty effective. There's also LAD cooling that runs filtered air across the face of the DMD of each chip.  |  IP: Logged

All times are Central (GMT -6:00)

This topic comprises 2 pages: 1  2

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.