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Author Topic: REALLY high gain screen Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 02-15-2003 10:57 AM                     You will need the silver screen for the light gain but also to prevent the polarized images from becoming depolarized which will "ghost" up the images. Silver screens for cinema are usually 2.5 to 3 in gain. Vutec, a screen manufacturer for industrial and home markets; produces a solid 10 to 13 gain screen on a rigid parabolic shaped surface which we have used for trade shows. The surface size is limited to a six foot width. Richard Fowler Kinoton America Inc.  |  IP: Logged Thomas Procyk Phenomenal Film Handler Posts: 1842 From: Royal Palm Beach, FL, USA Registered: Feb 2002 posted 02-15-2003 11:54 AM                     I never quite understood the concept of Silver Screens. I've worked in two locations that had them (one was a former COBB, so their silver screen was 1.85 with no masking ) and in both cases, the results were much like a big-screen TV. Those sitting in the left or right sections would be treated to a dim picture on the opposite side. Those sitting in the middle would see a really bright center, and then a falloff to the sides. True, we never ran any 3D movies, but running regular shows on those screens seemed almost distracting. When that old COBB was taken over by another company following Regal, they removed the silver screen and replaced it with a matte white one. The location I work at now has a silver screen, and two lenses in the back of the storage cabinet that say "StereoVision" on them. Assuming these are for the 3D, how would you use them? Is this setup for 3D movies that use the red/blue halo or where there are 2 of the same picture slightly off of each other? =TMP=  |  IP: Logged Jeffry L. Johnson Jedi Master Film Handler Posts: 809 From: Cleveland, Ohio, USA Registered: Apr 2000 posted 02-15-2003 12:43 PM                        A silver screen is essential to maintain the polarization of the left and right images of a 3-D motion picture.  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 02-15-2003 02:45 PM                     Most Stereovision lenses where for projecting over and under widescreen images. The lens barrel has two set of lenses bisected in the center and angled ( actually camera lenses converted for projection use ) and built in polarizers...some StereoVision sets had a 20% magnifier add on optic to increase the image size. The spacing of the upper and lower images varied since there where more than one supplier of 3D optics for production and required that you use the matching projection lens and test film for that spacing ( such as .387 ).StereoVision also supplied an adapter for anamorphic prints with a 1:33 image such as used for House of Wax reissue. Richard Fowler Kinoton America Inc.  |  IP: Logged Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 02-15-2003 07:03 PM                        Ok Silver screen a must. I see Hurley sells a 2.5 gain silver screen with perfs. This particular film is a side by side anamorphic print. I wonder if the over under lens could just be rotated 90° and used for side by side? I guess I'll do the screen first and see where I stand  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 02-15-2003 08:09 PM                     No, the over and under lens is different. The image it is looking at is about 2 perforation high X width while the side by side is 4 perf high x 1/2 image width. Richard Fowler Kinoton America Inc.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 02-15-2003 09:04 PM                        The StereoVision manual: http://www.film-tech.com/manuals/STEREOVISION3DPRINCIPLES.pdf  |  IP: Logged Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 02-15-2003 11:25 PM                        Thanks all for the input  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 02-16-2003 03:53 AM                        High gain screens, especially silver screens do have off-axis problems as mentioned, but they do have their place in theatres where the seating does not exceed the screen width by any significant amount. Also, with a silver screen attention must be paid to its angle so hot spots are not created. But when they are installed correctly in spaces where seating placement is ideal, they can be very effective. I visited a theatre in Kingston NY where the picture was about 45ft wide with an image that looked much brighter than the SMPTE standard 16fl and it was uniform from edge-to-edge; I was struck by the intensity of the image. I was sure he must be burning a 4.5kw - 7kw lamp to get an image that bright and uniform. When the projectionist took me up to the booth, I was expecting to see a big lamphouse and was really amazed to find that he was burning a 1600w bulb in a small 2kw Xetron. I couldn't believe it; how could that picture look so bright? Then he told me that he had a silver screen. I went back into the house and walked to the far isle seats but the brightness remained even from all seats. Just a tad fall off at the very front seats, which you would only expect people to sit in with full houses, and even then this would probably not be noticeable to the average viewer. This was an example of how good a very high gain screen can work in the right situation. Whenever I hear people bad mouth silver screens, I just recount that experience in a theatre up in Kingston NY.  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 02-17-2003 10:05 AM                        Ideally, high gain screens should be properly curved and aimed by ray-tracing. The projector's light should be reflected to a point in the center of the audience seating area. Otherwise, SMPTE Recommended Practice RP95 specifies "Installation of Gain Screens". One way to check for the proper curvature and angle is to hold a small mirror at various points along the surface of the screen. Hold the mirror to reflect the projector's light to the center of the seating area ("prime seats"). The screen's surface should be parallel to that of the mirror. If not, hold the mirror parallel to the screen's surface -- the mirror reflects the light to the same place most of the screen's light is reflected (hopefully not onto the floor or walls!).  |  IP: Logged Andrew Lee Film Handler Posts: 99 From: Oakville, Ontario, Canada Registered: Jun 2002 posted 02-17-2003 01:51 PM                     Most of you are aware about the trade offs and the advantages of using a silver screen. I don't want to make this forum a base for advertising but I thought it may be of interest to explain our new product. MDI now has a micro-lenticular silver screen available to theatres. This new screen is not only an excellent 3D screen (maintains polarization better than any on the market), it can be utilized for 2D projection as well. The technology behind this product creates a gain distribution which is much flatter than a standard aluminized screen. Hotspotting, and fall-off is drastically reduced thereby allowing the exibitor to present either without worrying about these issues. This screen has undergone evaluation by some of the studios and other cinema technology personnel and has had excellent reviews to date. A lenticular silver screen has been attempted from time to time over the past seventy years, but no one has been successful until now. Some of you will be seeing this product in your theatres in the near future. If you are curious and attending Showest, stop by and I will be happy to show you a sample.  |  IP: Logged Greg Mueller Phenomenal Film Handler Posts: 1687 From: Port Gamble, WA Registered: Jun 99 posted 02-17-2003 02:53 PM                        Tell us more! What's MDI? Do you have a website? Are they "made to order" (size wize) according to customer's requirements? Are they perfed?  |  IP: Logged Andrew Lee Film Handler Posts: 99 From: Oakville, Ontario, Canada Registered: Jun 2002 posted 02-17-2003 04:35 PM                     MDI stands for Marcel Desrochers Inc. We are located in Joliette, Quebec. Over the past 5 years we have manufactured over 10,000 cinema screens, over 200 specialty venue screens (Imax,Megasystems,theme parks,screening rooms,etc), 2000 home cinema screens and 3000 masking motors. Screen frames and masking systems are also manufactured here. It's a small company which has been growing consistantly. MDI had a rough start in the early days but is now coming on strong with quality products and fast delivery. Business is so good right now we are adding another 15,000 square feet to our facility. The website is MDI Our website is a little behind as our webpage employee has had an unfortunate illness that has kept him away for some time, but we will be updating soon. MDI has 4 perforation patterns with 2 more to be added to our production line later this year. Regards, Andrew Lee VP, MDI  |  IP: Logged Fred Georges Master Film Handler Posts: 257 From: Lombard, IL, USA Registered: Jun 2000 posted 02-17-2003 07:34 PM                     Gregg, Yes, the mirror box attachments CAN be used for side by side 3D. You just have to rotate them 90 degrees and place in front of your anamorphic lens. It's reflection management that you'll find challenging. The mirror box polarizer that has the best range of adjustment would be the Paramount though the easiest to use is the StereoVision.  |  IP: Logged

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