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Author Topic: 5/70? 8/70? 15/70? Brian Michael Weidemann Expert cat molester Posts: 944 From: Costa Mesa, CA United States Registered: Feb 2004 posted 03-16-2005 08:42 PM                        As the rolling loop is rolled across the aperture area, the cam catches the perfs and eases the frame across the registration pins. While the frame is projected on screen, the film frame is fully stationary. I'm not sure how much actual slowing down the "claw arm" does, but it must be a significant amount, seeing as it's the difference between damaged perfs after several passes, and none at all. As for the zig-zag tape splice ... it will vary from theatre to theatre, but the aperture can show pretty much up to the full frame; and the zig-zag cut WILL be visible on screen. This is why the tape splices need to be painted with an opaque photographic paint when they're made. The "lightning bolt" flash on the sides of the screen where the light seeps is more noticeable than a painted splice. Some theatres have narrower apertures and even an opaque tape could be used without showing on screen at all. an unpainted splice from Matrix Revolutions: The IMAX Experience A general slant splice wouldn't have an even enough hold. The zig-zag allows even distribution and maximum surface area for tape adhesion. You shouldn't get a situation where part of a different frame "pokes through". If you have to remove footage, it is replaced by black slug film. It cannot just be cut out, like 35mm can, because the sound synchs to framecount. And when assembling a film, there is no such thing as a "reference frame" to be left on the head/tail. You cut where it tells you! Or Spidey will come for you!  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-16-2005 08:59 PM                     Phil, Ya can't tell there's a septum there though..... why all the worry? Neil told me about the problems Imax had with supposed infringements on #4,114,996, the inlet giude. Told me he had to present his mathematical calculations to the courts for the design. Won that one as well as the inlet guide on the clones is completely different than Imax's. Phils Nightmare????? The cam unit is dead center in the photo. The curved input stator is to the left. The output stator is basically identical. The inlet guide(s-curve) is to the left of the input stator. Hope these photos help make things easier to understand for those that have not seen a 15/70 projector. Mark  |  IP: Logged Brian Michael Weidemann Expert cat molester Posts: 944 From: Costa Mesa, CA United States Registered: Feb 2004 posted 03-16-2005 09:23 PM                        What "clone" brand is that, Mark? I must admit ignorance, I've only become familiar with the IMAX GT. That looks remarkably like a clone of its basic layout, or possibly a very early model thereof?  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 03-16-2005 09:26 PM                     Must be annoying to need to to do lots of calculations after you BS your way into an Imax theatre and dismantle the projector to photograph and measure everything and copy a real engineer's design. Darn those patents, they do make for a lot of extra work when you steal someone's ideas Oh, Thomas: The "/" splicer is for magnetic sound film, this avoids the POP that a straight cut would produce as the steel (even some stainless) blade will always have a bit of magnetism. You could use it for striped release prints I suppose but I was told it was for the fullcoat or striped sprocketed recording tape used in sound recording and mixing (defore digital audio, there isn't much if any mag used these days)  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 03-16-2005 09:55 PM                     The zig-zag splice is to prevent the film from folding while in a loop shape. This would cause the film to jam in the projector.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-16-2005 10:37 PM                     Brian, Thats whats now called a Cinema Development Corp. projector or CDC. Same as the units that were installed by Iwerks and under a couple of other names. It dfinately has a far more sophisticated drive and control system than the Imax has for it's classics. Phil, that old coot, did alot of the developmental work on these projectors to get them into working-operational systems. There are a small but still growing number of them here in the U.S. and one dome system in Greece. The lastest install replaced an Omnimax system in Texas whose costs were killing the museum budget. Dave, Don't be ignorant! Patents do expire and then a design is in the public domain. I will admit that going in and making measurements did save them time, but thats about it. The first machine was produced but was not sold till after the patents expired. They still would have produced a machine without access to the other in perhaps just an extra 6 months or so. The input guide is 100% original design and Imax apparently agreed. Dude, remember, Imax didn't invent the rolling loop either, they just bought the design. I guess you can also call every other projector manufacturer on earth that uses the geneva movement a thief? Get a life or go bark up another tree! Mark  |  IP: Logged Brian Michael Weidemann Expert cat molester Posts: 944 From: Costa Mesa, CA United States Registered: Feb 2004 posted 03-17-2005 06:36 AM                        Yeah, I don't doubt that there are much better ideas out there for controlling the projector. The IMAX PLC is fairly intuitive, but I imagine that the possibilities with its software and hardware are endless. I mean, there must be infinite ways to arrange saving show lists, starting/stopping the projector and individual components thereof, monitoring systems readouts ...  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 03-17-2005 09:34 AM                     Actually Mark the original rolling loop couldn't handle the large film but chopped it quite nicely into 1 frame lengths (refered to as the autum leaves effect) that came spraying out the output side The rolling loop machine the use of the vacum and the use of air jets was the design work of a engineer named Bill Shaw and I doubt if the clones wouldn't hae happened at all if they adn't been there and created the market in the first place  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-17-2005 06:11 PM                     quote: Gordon McLeod The rolling loop machine the use of the vacum and the use of air jets was the design work of a engineer named Bill Shaw and I doubt if the clones wouldn't hae happened at all if they adn't been there and created the market in the first place Gord, I wouldn't argue that point at all, we can all thank those guys and give them the credit for perfecting it. My point is just that much of the Imax design is now in the public domain available to anyone that wants to persue it. Imax has repeatedly blown steam where steam can no longer legally be blown.... Mark Mark  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 03-17-2005 06:33 PM                        So how do 8/70 machines work? Are they basically the same as 5/70, or is it, too, a totally different format? I've run 5/70 (on JJs) and seen a couple of 15/70 installations, but I've never seen an 8/70 machine (except for the pictures on the Kinoton web site....  |  IP: Logged Adam Martin I'm not even gonna point out the irony. Posts: 3686 From: Dallas, TX Registered: Nov 2000 posted 03-17-2005 06:53 PM                     8/70 is a vertical pulldown format much like 5/70, but with 8 perfs per frame.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-17-2005 07:19 PM                     Have a look Here Mark  |  IP: Logged Richard Hamilton Phenomenal Film Handler Posts: 1341 From: Evansville, Indiana Registered: Jan 2000 posted 03-17-2005 09:32 PM                     Mark, What part of Greece? I did an install in Thessolinikki a couple of years ago. The complex had our 8/70. They also had a small digital 3d theater. They were just starting construction of the dome when I left the site. It was a pretty big complex, just wondering if its the same your talking about? Rick  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-17-2005 10:28 PM                     Hi Richard, Yes thats the place. Neil Johnson and company(CDC)did the 15/70 installation over there. We did a quote dorectly to them for the sound system. IN the end the sound system supplied was contracted out to some east coast company that specializes in Planetarium installations. We just don't have the manpower to handle that sort of thing in a foreign country. No problem here though. I would assume that all the other film exhibits are still running as well. Mark  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 03-18-2005 01:54 AM                  (NOT referring to Gordie)... So Dave, Hmmm...sounds like "some" IMAX employee has their nose up someone's ass and licking the corporate butthole. ...And has a bad taste in their mouth... and is crying sour grapes while "SMELLING" the roses. GET A LIFE! It's just showbiz! OH, AND BTW: GET the REAL facts before you spout off about stuff you ain't got NO clue about! GEEEZE! Background: I agree... Shaw was a great engineer and way back in the 70's brought the rolling loop projector into the real world. The BIGGEST real world IMAX contribution was when the deceleration cam and claw was incorporated into the original rolling loop projector design and helped to stop all that film-perf damage. OBTW: Neil's CAM design and IMAX designs are TOTALLY different! You're implication just points how stupid your statements really are since you have NO clue! The IMAX version is a 3-dimensional cam and Neil's is a single flat, 2D plane. BTW: I personally have designed and ran the CNC programs for more than 10 cam profiles all of which were a MUCH better design than IMAX and provided a more gentle handling of film than the IMAX design. You really are un-enlightened. Also, until the competition got involved, IMAX was WELL know in the industry for their shitty lenses with their lack of sharpness and resolution, and their projector's crappy handling of film. Not only did they have shitty film input curves to the rotor and control/safety/show-control logic, they were also know for fucking over the customers in their biz practices. They FINALLY "got it" because of the competition from a couple of companies and upgraded their product and stopped fucking their customers without a rubber. When they finally got "Religion" is when the competition drop out. END OF THAT STORY! However, I sincerely respect IMAX and have to hand it to them for digging themselves out of their greedy $ hole and re-defined themselves and moved on to more creative and inspiring things. They are finally being honest people rather than money-grabbing assholes. They will be THE film company long after 35mm exhibition has gone to TV (Video) Rick: I think Mark is referring to an Iwerks/CDC installation at the Athens 2004 Olympics that was plagued with many problems due to shitty theatre design. Even though Mark alluded to him, the "Know-It-All" loser project designer/manager was/is the Sky-Skan head himself that weaseled his way into that position and fucked up many things at that venue. Including stupid mistakes relating to patron's heads interfering with the projection and appearing on screen that Iwerks had to point out for correcting. A very costly mistake that had to be corrected during construction that was already underway. [ 03-18-2005, 04:03 AM: Message edited by: Phil Hill ]  |  IP: Logged

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