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Author Topic: 16mm Projector B&H Out of Sync Antonio Castles Film Handler Posts: 6 From: Bogota, D.E., Colombia Registered: May 2012 posted 06-07-2012 09:27 AM                     Hello, I'm an art student from Bogotá, Colombia. Recently, I started to work with 16mm film. I have 2 B&H Projectors (1693 and 2535), and I decided to do an installation. I cut a segment of film and made it run through both projectors at the same time. Both were set at 24 fps, but after a while it was evident that the 1693 projector was running a little bit slower, and the film started to stretch progressively. What can I do about it? there are no repair services here. It is an almost unnoticeable problem, but its a big problem for my installation. How can I make sure that both projectors run at the exact same speed? Also, I have considered to make loop projections, but I can't seem to find any projector loopers at an affordable price. Is there a free design out there? Can they be home made? Is it possible to find one design that works also with super 8? Thank you for your time.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 06-07-2012 10:17 AM                     There is no way to perfectly synchronize the two projectors without spending a lot of time and money. Standard electric motors just run at their own speed and that's that. You would need to change the projector's motor to a synchronous type which "locks" to the frequency of the electrical supply and runs at a specific speed all of the time. That's just WAY too involved for the average person to do. That assumes that you can even find synchronous motors that fit those projectors. There are other ways that you might synchronize two projectors but they are equally involved and expensive solutions. However, there is another way: Use a "film accumulator." Basically you are making a zigzag path for the film to travel between the two projectors which takes up some slack in the film. If one projector runs faster than the other, the zigzag loop grows or shrinks, allowing the film to keep moving without problems. See the thread here: http://www.film-tech.com/ubb/f1/t010147.html  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-08-2012 08:26 PM                     True, with B&H that uses induction motors along with being belt driven to the mechanisms, gonna be tough to sync.  |  IP: Logged Antonio Castles Film Handler Posts: 6 From: Bogota, D.E., Colombia Registered: May 2012 posted 06-09-2012 07:06 PM                     Thank you very much for your help. I have some questions though: can I do my own interlock accumulator? Isn't it possible that the film would eventually tighten because of the different speeds of the projectors? Is the principle behind accumulators the same as loops inside cameras? How does that work? Thank you again  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-09-2012 09:16 PM                     I've seen twin locations that used a homemade form of accumulation where the far (no.2) machine was slower. Thus, the film was set snug between the two at beginning and towards the end of the performance, the film would be almost half down between the two outside rollers with the weighted roller in the middle keeping the film taught. Thus, in your case, the one 16mm (1693) that runs slower should be your far machine. Good luck - Monte  |  IP: Logged Antonio Castles Film Handler Posts: 6 From: Bogota, D.E., Colombia Registered: May 2012 posted 06-09-2012 09:27 PM                     Thank you Monte. Sadly, I didn't get a word of what you said. Is there an article, or book or something for beginners that I could read? I would like to get used to some concepts before trying anything. I might as well be making you loose your time pointlessly since I don't understand what you say.  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 06-09-2012 10:19 PM                     Yes, you can make your own accumulator. You can make it out of parts you have on hand or buy from the hardware store. The most important thing to watch out for is to make the film path clear of things that can damage film. Use rollers at all places where film makes contact. Make sure nothing touches or drags on the film. Ensure that the path is as straight as possible to avoid kinking the film or causing it to "jump off the track." You could use empty spools of thread for rollers and you could use yard sticks (meter sticks) to hold things together. Just think. You'll come up with something. Be creative. You'll need to know which machine runs fastest and which machine runs slowest. Then you adjust your system to account for that. Assume "Projector #1" is the one where the film starts out and "Projector #2" is the one where the film ends up. If Projector #1 runs faster than Projector #2 then the zigzag loop of film will GROW as the presentation runs. If Projector #1 runs slower than Projector#2 then the loop will SHRINK. Keep this in mind when you build your system. If you have a situation where your film loop grows, set your accumulator at the top of its travel when the show starts so that it will get lower as the show goes on. If your loop shrinks, start the accumulator at the bottom when the show begins. If I had my choice, I'd arrange things so that Projector #1 is the fast projector and Projector #2 is the slow projector. That way the loop will grow and the accumulator will get lower during the show. This way, if things don't go as planned, you will not have a disaster on your hands. If your loop grows too big, the worst thing that could happen is that you end up with film all over the floor. This is not a good thing but it's not a "show stopper." If you do it the other way, in a "shrinking loop," you could run out of film. Your accumulator could end up going all the way to the top and there won't be any more slack. The two projectors will start a game of "Tug of War!" You could damage your film or damage your projectors but you will almost certainly stop the show. Whatever happens, nothing good will come of it. Okay! Now it's time to get out that box full of Legos that have been stashed in your bedroom closet since you were a kid!  |  IP: Logged Antonio Castles Film Handler Posts: 6 From: Bogota, D.E., Colombia Registered: May 2012 posted 06-10-2012 10:30 AM                     Thank you Randy! I seem to understand something now. However, I think I did not make myself clear from the beginning. By loop I mean that the film will never stop rolling, I'm planing to tape the beginning to the end. Impossible?  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 06-10-2012 01:15 PM                     How long is the presentation? Does it have to run continuously all day long or does it stop after a time? If you are running an endless loop system, you'll need two accumulators. One for the "outbound" leg and one for the "return" leg. If the projectors don't run at the same speed, one of your accumulators will eventually "bottom out" and the other will eventually "top out." The time it takes your system to reach its limits is dependant on the speed difference between both machines and how much slack you have built into your accumulators. If the speed difference is small and your accumulators are large, you might be able to run for hours without stopping. If the difference is to large and/or your accumulators don't hold enough film, you might only be able to run for a few minutes. This is something you're just going to have to experiment with and figure out. Some suggestions: Set your system up the best way you can then time out how long it takes to bottom out. Then, come back and stop the system and reset your loops before starting again. Try putting an electrical timer on the system so that it stops the projectors in time to prevent a disaster. Further, you could rig an "emergency switch" into your accumulators such that they will shut the system down when one of them "tops out." Regardless of what you do, you'll have to use Yankee Ingenuity to make this work. You might as well put both the stop switch and the timer in there just for double safety.  |  IP: Logged Antonio Castles Film Handler Posts: 6 From: Bogota, D.E., Colombia Registered: May 2012 posted 06-10-2012 09:00 PM                     I have another question. I saw some time ago in a couple of museums some projectors that had an accumulator (i guess) which was like a horizontal disk between the arms of the projector in which the film was placed. It spinned, winding the film on its outer side and sending it back to the mechanism from the inside of the circle. How is this device called? Is there any way to make one easily? could I do the setup I'm planning with both this system and the accumulator that you are suggesting me?  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 06-10-2012 09:47 PM                     I am guessing that you are talking about a platter system. Something like this? A platter system holds the film instead of the traditional reels. The idea is that you load the entire movie onto the platter then play it all the way through without stopping, sometimes as long as four hours or more. The main benefit is that you never have to rewind the film because it automatically rewinds while it plays. It is similar to the way the old "8-track" audio tapes used to work except they are not endless loops. On a film platter the show ends when the film runs out. Then you rethread the film and start the show. The platter system is what allowed the growth of the super "megaplex" theaters with 10 or 20 or more screens in one building. With good equipment and properly trained operators, it only takes two people to run 20 screens. There are such things as "endless loop" platter systems which never have to stop once you get them working. The active phrase here is, "Once you get them working." They are grouchy things. If everything isn't JUST right, they can go crazy on you and damage film. Even when they work they way they are supposed to, they often scratch film over time. Learn more about 16mm film transport mechanisms by clicking this link: http://www.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=007970#000000 While I suppose you could build or buy one of these devices, I could never hope to explain how to build and operate one over the internet. There are just too many crazy things that can go wrong that you can't write down in a text message.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 06-15-2012 05:30 AM                     Is that an LP and Assoc lamphouse that used a vertical bulb and glass reflector?  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 06-15-2012 06:56 AM                        LP, but horizontal and metal. I have one exactly like it. Louis  |  IP: Logged Randy Stankey Film God Posts: 6539 From: Erie, Pennsylvania Registered: Jun 99 posted 06-15-2012 07:53 AM                     L.P. Associates - Horizontal (2,000 W) - Metal Reflector.  |  IP: Logged

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