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Author Topic: Mirror Projection Michael Dolan Film Handler Posts: 77 From: Deerfield Beach, fl. Registered: May 2008 posted 06-22-2008 03:47 PM                        Ok so some guys were here again today going over stuff for our two Digital projectors we have coming in. My question is the two theaters that are getting the digital they are trying a side by side deal with the digital and 35mm but we don't really have the space. They were talking about putting the 35mm behind the digital facing to the side and using a series of mirrors to project the image to the screen. I have never seen this done and want to know what that even looks like. Does anyone have any pictures of something like this? and does it change the quality of the picture or the way it runs?  |  IP: Logged Mike Schindler Phenomenal Film Handler Posts: 1039 From: Oak Park, IL, USA Registered: Jun 2002 posted 06-22-2008 04:23 PM                     Check out the pictures of the Ogden 6. From what I understand, it eats a lot of light.  |  IP: Logged Joe Redifer You need a beating today Posts: 12859 From: Denver, Colorado Registered: May 99 posted 06-22-2008 05:37 PM                        Sounds like your guys are more interested in making some money from the sale and install than they are with the quality of the presentation.  |  IP: Logged Richard May Phenomenal Film Handler Posts: 1057 From: Floral Park, NY USA Registered: Aug 2004 posted 06-22-2008 06:16 PM                     It's also just another way for them to make look better than film. Mirrors suck.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 06-22-2008 08:39 PM                        Mirrors get dirty, mirrors get MOVED. There is a reason why 35mm projector heads are mounted on humongously heavy pedestals and consoles -- so they don't get jarred around. How are those mirrors going to be mounted and with what kind of rig that would allow fine adjustment of the mirrors so that all the corners on the screen are at perfect right angles without any distortion? What's going to stop that rig from being bumped and ALL the hours of alignment shot to hell? And believe me, it will take hours to get it right....or sort of right, which is about the best you can expect. I once participated in such a folly (it wasn't my idea) and it went down to a quick and ignominious defeat. Do yourself a favor...say NO THANK YOU.  |  IP: Logged Kenneth Wuepper Phenomenal Film Handler Posts: 1026 From: Saginaw, MI, USA Registered: Feb 2002 posted 06-22-2008 09:27 PM                     Years ago, 1960s, the Bush Film and Equipment Company here in Michigan manufactured an interesting classroom projection system. There was an RP screen on a slide out box at the front of the machine. Beneath the slid out screen were speakers for the sound. Inside was a Kodak Pageant projector mechanism and a custom built amplifier for the sound. The reels of 16mm film could stick out of the box through coverable slots. 1,600 feet of film MAX! The lens was very wide angle and projected to a front surfaced mirror and then to the back of the RP screen. The system worked pretty well as there was less need to darken the room and the mirror reversed the image for the rear projection to look right from out front. The mirrors were very costly and could be dulled by improper cleaning or scratched by wiping dust across the surface. I doubt that two such mirrors would produce satisfactory results for theatre use. KEN  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 06-23-2008 04:28 AM                        There was a theatre on Flabush Ave in Brooklyn of which I only have a vague recollection of the name, possibly the Avon? It closed soon after I got here, but what I do remember was that it was the only theatre I have ever heard of that used an RP screen instead of front projection. The presentation quality however is vividly etched into my memory as it was horrific. Evidently getting the image big enough required a severe wide-angle lens which gave barrel distortion and when combined with the RP screen caused a terrible hot spot in the middle of the screen. The multiple mirrors themselves added to the distortion. And of course the RP screen precluded putting speakers behind it. Plus, the sound of the projector could clearly be heard. Were there change-overs? How do you do change-overs with mirrors? Possibly place the projectors facing each other and project both beams into a prism? This was in the early 70s so I assume platters weren't common yet. Although I never saw the setup, I was told that in order to get the picture a descent size, they had to fold the image a few times due to the limited space behind the screen, with each mirror needing to be bigger and bigger, distorting and dulling the image more. They couldn't do CinemaScope with this setup as the fall-off on sides would be too extreme. I can't imagine how difficult it must have been to align multiple mirrors.  |  IP: Logged John Wilson Film God Posts: 5438 From: Sydney, Australia. Registered: Dec 1999 posted 06-23-2008 05:15 AM                     I ran mirrored projection in the old Penrith 1+2 in the late 80's. The original mirror had imperfections which looked very bad when magnified. They replaced the mirror and it looked OK...but it wasn't a very big screen so that may be why it looked OK. If they're going digital, why keep the 35mm? If there's no room, then there's no room.  |  IP: Logged Phillip Grace Expert Film Handler Posts: 164 From: ACMI. Melbourne. Australia. Registered: Mar 2004 posted 06-23-2008 05:19 AM                     Hi Michael. That proposed arrangement really sounds like doing it the hard way! It would make more sense to me to install the digital projector sideways near the front wall of the booth and use a single mirror at 45 degrees to turn the image and shoot it out through the projection port alongside the 35mm image. It should be possible to flop the image over electronically at the projector, as is done for rear projection. Only one reflecting surface to lose light etc. Diverting the light beam from the 35mm projector as described will be harder to do, require larger mirrors and projection ports, and degrade what should (still) be the better motion imaging system. How big is the digital projector? How small is the booth? Cheers. Phil.  |  IP: Logged Andy Frodsham Expert Film Handler Posts: 238 From: Stoke on Trent, Staffs, UK Registered: Nov 2006 posted 06-23-2008 06:24 AM                     In the early seventies when some of our larger old cinemas were divided-up to make smaller theatres, the installers always tried to contain all the projection equipment in a single booth. This often resulted in some of the theatres receiving the projected image via a periscope type system; some directly. Audience members in the know would always try to book seats in the theatres which had 'direct' projection - the picture via mirrors looked crap! I remember in the mid seventies seeing THE EXORCIST projected via mirrors into a small auditorium of a, once large, London cinema (A Warner theatre, I think). I also recall that the very wide beam of light emerging from a mirror in the rear wall was quite distracting! In a projection setup I would avoid any mirrors like the plague!  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 06-23-2008 07:20 AM                     Personally I would not use these guys for your install! What they have come up with is a joke. I recommend that you install a second port for the digital stuff, a port is far less expensive than the front surface mirrors you will need to go the mirror route. If you are lucky enough to get Christie gear all the operator controls are at the rear. Installing wheels on the base would allow you to retract the projector back to do a lamp change. Pretty simple really... although in all instances of having done this for our customers the film gear has never been used again... I recommend that you research what you are purchasing and the guys you've hired very thoroughly before you ever go to the next step... To me it sounds like you are getting digital gear that has to side mounted operating touch panels. Mark  |  IP: Logged Andy Frodsham Expert Film Handler Posts: 238 From: Stoke on Trent, Staffs, UK Registered: Nov 2006 posted 06-23-2008 08:04 AM                     I suppose it's a kind of back-handed compliment to 35mm! They know that 35mm will (to some extent) handle being projected via a mirror - although it will end-up looking crap. The digital stuff couldn't cope with mirrors - it looks crap to start with!  |  IP: Logged Mark Lensenmayer Phenomenal Film Handler Posts: 1605 From: Upper Arlington, OH Registered: Sep 1999 posted 06-23-2008 02:51 PM                     Some of the early (70's era) AMC installations used mirrors in every auditorium. The projection rooms and auditoriums were on the same floor, so they did not have to go to the expense of putting in a second floor. They used a mirror system (2 front sided mirrors) to "periscope" the image about 8' up so it cleared the heads of the patrons.  |  IP: Logged John Wilson Film God Posts: 5438 From: Sydney, Australia. Registered: Dec 1999 posted 06-23-2008 05:50 PM                     quote: The digital stuff couldn't cope with mirrors - it looks crap to start with! Not the digital shows I've seen.  |  IP: Logged John Walsh Film God Posts: 2490 From: Connecticut, USA, Earth, Milky Way Registered: Oct 1999 posted 06-23-2008 05:53 PM                     I agree with everyone above, especially Joe; only really crappy theaters would use mirrors. What about that 'image mover' system MIT makes to slide projectors left/right on tracks?  |  IP: Logged

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