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Author Topic: Modifying Aperature plates Don Bruechert Mmmmmmmmm, bird! Posts: 340 From: Manitowoc, WI, USA Registered: Jan 2003 posted 03-26-2003 01:15 PM                        Another screen related question. In one of our houses when we show scope movies the picture rides way up at the top of the screen, and of course we don't have any decent masking to cover the 3 feet of unused screen at the bottom. I was wondering if it was possible to try and order a special aperature plate that was set up so we could run the picture lower on the screen. My theory on this is that if you run the movie out of frame it would be lower on the screen, and you only see the top frame line and lose the bottom because of the cut of the aperature plate. If the aperature was cut lower in the plate would it not then be possible to run the image lower on the screen?? I know these questions may appear stupid, but one has to learn someplace!!! It is not as simple as moving the projector because it is perfectly aligned for flat - I try to run flat in there whenever I can, but next week will be one of those cases where I will have to run a scope film in there, and we always get customers coming out and telling us the movie is out of frame. We are working on masking for that screen, by the way, but things like that in our place move about as fast as molasses in December....  |  IP: Logged Thomas Procyk Phenomenal Film Handler Posts: 1842 From: Royal Palm Beach, FL, USA Registered: Feb 2002 posted 03-26-2003 01:20 PM                     Sounds like your scope lens may be out of alignment. Are you using turrets or manually changing the lenses? =TMP=  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 03-26-2003 01:36 PM                     Run some RP 40 and make sure you have the right ratio for Cinemascope. It could be that you have the wrong size lens, a mis-cut aperature plate, or the plate might even be upside down. Don, as a teen-ager in 1958, I was orginally from Manitowoc. As a kid, I only remember this about the theatres: The Capitol.....it is running now as a Performing Arts Center. The Strand......it is now a six-plex and is still running. The Empire......long gone, now home of TEAM Electronics. The Mikado......long gone, now a home of a church. The Lake-Vue Drive-in...long gone, was next to WCUB. I understand there is a multi-plex in a mall, I think it is between Manitowoc and Two Rivers. Which theatre is yours? I would suspect the one in the mall is, or maybe the Strand. Is it equipped with Century? If it is a Century, it could be the aperature plate is in upside down or someone might have played switcharoo with aperature plates from adjacent houses. Seen that happen many times, and it'll drive the projectionist nuts! In any event, find out what the problem actually is before you start sawing on aperature plates. New aperature plates are tailored to the screen. Very seldom have I seen a perfect fit of a new aperature.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-26-2003 02:23 PM                        You would probably lose a lot of light by projecting out of the bottom of the aperature, not to mention the wear on the mech caused by always reframing. You'd be better to shim the lens instead.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 03-26-2003 02:26 PM                     A stupid question: Are you sure that you are using the correct aperture plate for that lens/screen?  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 03-26-2003 02:43 PM                        http://www.kodak.com/US/en/motion/newsletters/pytlak/spring2001.shtml Always use a test film like SMPTE 35-PA (RP40) to verify you are showing the correct image area. If the image position was correct before, something has changed. Filing the plates may just be putting a "band-aid" on the problem. Normally, both scope and flat should use the same optical centerline, so reframing is not necessary.  |  IP: Logged Don Bruechert Mmmmmmmmm, bird! Posts: 340 From: Manitowoc, WI, USA Registered: Jan 2003 posted 03-26-2003 06:11 PM                        Paul (and others), The image fills the entire width of the screen and doesn't look distorted, it just rides really high on the screen. I've only been into this for 6 months, but I am told it has always been this way and that when the house was built the guy told the owner the vast majority of movies were flat, so he believed it and they somehow optimized the setup for flat and didn't pay much attention to scope. Several of us had a discussion last night when I was grumbling because I had to run a scope movie in that house, and they suggested I post something here to see what possibilities exist to lessen the suckiness! How would the aperature plate be upside down? It only goes in one way, unless you put it in backwards, which I suppose might be upside down, but I never tried it the other way.... Maybe I'll mess with that once and see what happens just for kicks. I know the plates and lenses are all for their specific booths, and they are all labelled so the old switcharoo would be difficult to do. Paul, just FYI.... The Capitol is a Performing Arts Center now. I live here The Strand is where I work, yes a 6-plex The Empire is now a culligan man store and a mattress vendor (Team moved) The Mikado, saved from being a church, is now Lakeshore Cinema (a buck house) The Lake-view I am just old enough to remember a few movies there, but is a hayfield now... it's for sale if you want to buy it!! There are also building a 4-plex on 35th and Dewey called Family Cinema, which will also be a buck house.... There's nothing at the mall (literally!). There... now you are caught up! (and I know how old you are!) Have no intention of hacking the aperature plate - was thinking more along the lines of paying someone to determine if it is the right one.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-26-2003 07:43 PM                     If they are still running those old Brenkerts I installed when they went to 4 screens, then the plates can't be in upside down. Hopefully those were junked a long time ago. If its the Brenkerts they always had lens barrel problems with maintaining screen alignment when changing scope/flat lenses. You have to open the dowser and align it on screen...then lock the screw to tighten them down. I remember installing one X-L in Theatre 5 there...don't remember whats in #6...probably another XL I rebuilt. Mark  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 03-26-2003 07:59 PM                     Don, shim your lens barrel or lens. It may help the problem. Also, rotate the scope lens 180 degrees and see if the image shifts. It could also be that the primary and scope lens could be crossthreaded, causing it to cock a little, but I doubt it. I don't know for sure what kind of proectors you have, but if they are Centurys, the aperature plates can be installed upside down. It is impossible for this to happen with Simplex XL's and Brenkerts. Is that old Motiograph AA still in the orginal house? I think Mark might have changed it....but I am not sure. Thanks for the update of the old home-town theatres. Appreciate it.  |  IP: Logged Don Bruechert Mmmmmmmmm, bird! Posts: 340 From: Manitowoc, WI, USA Registered: Jan 2003 posted 03-26-2003 09:11 PM                        Mark, I am not that up to date on all our equipment yet - they have been after me to do the booth inventory for a while, but we have had staff shortages. I am proud to say I have figured out how to do oil changes now and we have half of those done. I didn't know how much oil a projector holds, so I have enough oil around now to last the rest of our lives!! #4 and #6 have Kniesley consoles. I am under the impression that all of our projectors are simplexes, but these two have different gates - they have a curved front and a thin stainless area behind that is a real pain to use the toothbrush on. All our other projectors have flat gates on them. The aperatures (which look the same everywhere) have a black plastic handle, about a 60 degree bend -\___ and then the flat area that has the aperature in them. The actual aperature has an indent around it on one side. They really only go in one way so they lock. You can kid of tell if you have it in backwards. I'm pretty sure the lenes are schneiders, and I know the one in #6 for sure has the converter gizmo on it (sorry, my memory sucks). I don't think it is a regular scope lens, I think it is the modified deal I have read about on here. #1 and #2 are the blue Xetron 2000's, #5 is another console, but I just can't remember the name, and #3 is a really old lamphouse but it still has a simplex head on it. We have mostly kelmar automation, and as far as I know all of the soundheads are RCA and they have been outfitted with the ??reverse scan? LED system except for #2 which has some kind of LED lamp that goes in place of the exciter lamp and hums like a mother when you turn on the lights in the booth. That's about all I know about our stuff at the moment.  |  IP: Logged Kenneth Wuepper Phenomenal Film Handler Posts: 1026 From: Saginaw, MI, USA Registered: Feb 2002 posted 03-26-2003 10:06 PM                     Hello Don, Welcome to the wonderful world of Cinema. You may have determined that your images are correct and just don't realize it. The condition you describe is perfectly normal for a CONSTANT WIDTH screen image. Both the flat and scope images fill the screen from SIDE to SIDE, Right? Then there will be a blank space above and below the scope image which, along with the flat image, is centered vertically on the screen. It is necessary to have MOVING MASKING to cover the blank space at both the top and bottom of the screen. This masking can be manually or mechanically positioned but it is required for your type of image. If you are disturbed by the blank space at the bottom of the screen, you might tilt the projector. Then all of the blank screen will be at the top. If the images filled the screen from top to bottom, CONSTANT HEIGHT, then the flat image would be narrower than the scope image making it necessary to have masking at the sides to cover the unlighted area of the screen. You might like to try the Schneider lens program in your computer as it will show you the way these images inter-relate. I do not believe that you have aperture plate problems. KEN  |  IP: Logged Don Bruechert Mmmmmmmmm, bird! Posts: 340 From: Manitowoc, WI, USA Registered: Jan 2003 posted 03-26-2003 10:23 PM                        Yes, I have a constant width. My issue is that there is not space above and below the image, but only space below. If the image was centered vertically on the screen it would not look like it is out of frame. With the image constantly sitting on the top of the screen people constantly complain that we have it framed wrong - we do not, that's just where it lives. The masking (or lack thereof) is a whole other issue! Changing the projector angle is probably not a good idea because that would affect the flat image as well, which is perfectly centered in all directions on the screen.  |  IP: Logged Daryl C. W. O'Shea Film God Posts: 3977 From: Midland Ontario Canada (where Panavision & IMAX lenses come from) Registered: Jun 2002 posted 03-26-2003 10:35 PM                        By the way... exactly how far off is the screen image? A foot, a yard...? And... it wouldn't be the first setup that I've seen that a few pumps on the jack handle was part of the flat to scope procedure.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 03-26-2003 11:06 PM                     Hi Don, Yea....now I remember I moved the Xetron console out of 4 into theatre 5, and I put the Kneisley consoles in 4 & 6. Sounds like da boys got rid of all the Brenkerts at last!! I seem to remember that you have a 1:85 screen in # 4 or 5, or perhaps both, and that we went for the whole scope image shrunk down so you would have constant width and preserve the entire image. Da Boys didn't want scope screens as they would have been just a narrow band across the front walls so I put in 1:85 screens! That was a long time ago....... You will need a loop of RP-40 to run and check lens alignment on screen....view the two formats without aperature plates in the machine. Start with 1:85 and frame the target so its at the appropriate marks on the target at the top, bottom, and left and right. Then, with out touching the framing at all(!!!) switch to your scope lens. The image should still be centered on the screen left to right fairly closely...keeping in mind that anamorphics do generally cause a little image shift either left or right. Then check top and botton to see if you're still centered. With a little luck it should be. Then slip the scope plate in the machine and see what happens. If the apreature masks off more to the top than the bottom and the target is out of frame then you need to cut a new plate, This is just the basics of doing this...to do things correctly you want to be sure that a number of other things I couldn't fit in here are also in line properly, but this should give you an easy, simplified way to check it out. Another thing I seem to remember is that da boys wanted it cut that way for some reason or other. I remember that they didn't even want manual turretts, which would have made aligning things on screen for you alot easier. Those old pot metal Simplex 4" barrel adaptors are pretty crappy sometimes, the present 4" adapters are much, much nicer. I almost always cut plates from pinhole type apreature plates as I only had to stock one size. A nibbling tool from radio shack speeds up opening it up, but don't go at it too fast...take very small nibbles....and with a a LaVezzi apreature file open it out and clean up the edges. Ideally the edges should also be beveled so they focus as sharply as possible...you need a fine file with no serrations along the edges!! Cutting plates is an art and it takes patience and time. I suggest you get at least three plates and a couple of files to start with the first time. Mark @ CLACO P.S. Tell da boys I said hi!!  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 03-26-2003 11:28 PM                     ....and remember that when you cut the aperature, everything is bass ackwards on the aperature plate because of pic inversion through the lens. As Mark said, position the lens for the best center vertically and horizontally, then lock it down and start your aperature work. It is going to be a compromise when you take your file and start filing. Be advised you should make sure the projector is set for the correct angle. Otherwise, you might have some "goofy racking" when you thread until you get used to where the frameline is supposed to fall in the framing aperature. If you are skiddish about cutting a plate, In August I might be back in Manitowoc for a class reunion. If so, put on the coffee pot and I'll come over there and rip one out for you.  |  IP: Logged

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