Kinoton FP25D threading question

[Steve Pike]

Hi

I have recently installed an FP25d in my home cinema after acquiring it from the cinema I work at as a projectionist.

Now, this projector works fine but the last time I used it fully was when we had our last 35mm film back in 2011! So I've become a little rusty with one aspect of the threading that always confused me back in the day regarding the loops above and below the gate.

The manual states that a film loop of about 4 frames (16 perferations) should be above and below the gate otherwise it could damage the film or warble the sound.

My query has always been, where do the loops start and end?

I've tried a number of combinations but it still produces quite a loud "clackerty" sound when projecting.

Image attached show the top loop that I have tried. The start of the loop (and first of the 4 frames) is when the film starts to bend away from the gate. With the end of the loop ending as the film meets the feed sprocket.

The bottom loop is also 4 frames commencing from the point it exits the intermittent and ending when the film enters the black guiders shown.

Questions I have; Do the loops need to be bigger or smaller? Where should the loops begin and end? Should the top loop 4 frames start from the point the film starts to curve or from when it's just about to exit out of the skate?

Should the 4th frame in the loop (on the top loop) be where the end of the shoe is on the top feed sprocket?

With the bottom one, is it 4 frames in the gap between the intermittent sprocket and those black guiders?

Sorry this may sound like such a draft set of questions, I just don't want to damage the film! And it's been a query in the back of my mind for almost 10 years!

Cheers

[Ed Gordon]

This might help. It is a 15 minute video on the Kinoton FP30D.

https://www.youtube.com/watch?v=yiK-vP946rQ

[Randy Stankey]

Except for sound offsets, loops aren't super critical.

Loops need to be large enough to allow slack for the film to move without tugging but small enough that they don't "flap" and damage film. The optimal loop size varies with the projector model but I have always made my upper loop as tall as the top of the feed sprocket as a starting point then adjusted by trial and error until I have it working the way I want it to.

The lower loop is different because you have to account for the 21-frame offset between the image at the gate and the sound scanning point. Get a piece of leader or scrap film that has an "X" marked on one frame then count down 21 frames and mark a star on the 21st frame. Thread that piece of film with the "X" in the gate and the "★" at the sound scanning point. That's your starting point for your lower loop.

You might want to advance or retard the film at the sound point by a couple-few sprocket holes to tweak your lip-sync.

If you have a large auditorium, the distance from the speakers and the listeners might make the sound seem a bit out of sync. Moving the scanning point forward or back one or sprocket holes will change the place in the house where the sound and picture appear to sync up.

Again, experiment until you have your loop and your sync working the way you want them to.

If you have a sound penthouse or a digital sound reader, the upper loop size will need to be determined the same way that you did the lower one. Yes, it's possible to change the sound offset on a digital sound system but, once set, you still have to thread the film the exact same way or else your presentation will look like a bad Chinese Kung-Fu flick!

You can use a Sharpie marker to make a small mark inside the projector housing to use as a reference point when threading. That way you can thread the projector, just the way you want, every time. After you thread the projector a few million times you'll just "know" how to thread and, eventually you might even be able to do it blindfolded.

I won a bet, once, when somebody dared me to thread a projector while my eyes were shut. I did it, platters and all, in 93 seconds!

[Leo Enticknap]

With the FPs, I was taught to form the top loop such that its apex was level with the top of the skates at its highest point (just before the pulldown).

As Randy said, the size of the intermittent loop is determined by the sound offset: a leader number in the gate, and its corresponding sync mark in the beam of the exciter.

The only exception is if you're running a really rough print - shrunk, with perf damage, and/or multiple suspect splices. In that scenario, I'd add a couple of extra perfs to the loop top and bottom, double check that the racking handle is as close as possible to the center of its travel, and bugger the sync: because if it jumps a perf while the reel is running, you might need the extra wriggle room to bring the picture back into rack. I'd far rather have the lip sync seem a tiny hair out for someone sitting right at the front or right at the back, than have the picture jump a perf or two out of rack and be unable to correct it (because of the risk of running out of loop) without stopping the projector.

The last time I worked in a cinema with FP-20s was from 1996 to '99 (I also worked with an FP-38E from 2014 to '17, but we only ever used it for 16mm), so I'm a little rusty, too. However, that was the period when polyester was replacing cellulose triacetate for release print stock, and my memory is that polyester always ran noisily through those things, no matter how much you faffed around with the gate pressure, replaced worn skates and runners, etc. etc. Polyester film base is thin, tough, abrasive, and noisy, and that projector was designed two generations before it existed.

[Randy Stankey]

The only exception is if you're running a really rough print...

You're supposed to make sure you time the intermittent at the bottom of the pulldown cycle. Right?

That way, the top loop is at the smallest it will be during the cycle and the bottom loop will be largest.
If your intermittent sprocket skips a sprocket hole at startup time, there's just a wee bit more slack in the loop before the sound sprocket tries to pull it away.

That's the way I've always done it, ever since I can remember.

[Emiel de Jong]

As I feel it, those loops in the photos are too big. In the older FP20's and FP30's there was a trip switch which even would make it impossible to make the upper loop that big. I would say the film should sort of follow the direction from where it comes out between feed sprocket and pad shoe. Big loops are noisy, and the lower loop in the photo looks like it can slap against the shutter housing. My "trick" was threading the film, intermittent sprocket just before pull down, around my index finger against the left side of the guide roller just below the intermittent sprocket. What I would do is try some smaller size loops and see where the loop is moving most quietly and "easily" without of course being so small that the film is moving tight against pad shoes and skate at entry and exit points.

FP20tripswitch.JPG

[Leo Enticknap]

You're supposed to make sure you time the intermittent at the bottom of the pulldown cycle. Right?

I have to confess that I've always done the exact opposite: inched the mechanism such that the intermittent is "in neutral," but with the pulldown just about to start. That leaves the top loop at its largest, which I'd thread to be level with the top of the skates (which were of a slightly different design, shorter, and with no trip switch than the ones in Emiel's picture), and the intermittent loop about to expand, to absorb any slightly delayed shock as film being dragged across the scanning drum causes it to start rotating. If you do it the other way, the intermittent loop will shrink as the drum starts to pull. I guess either way has its pros and cons.

I was never really worried about the film jumping during the initial motor ramp-up. Unless there is a mechanical fault with the projector (e.g. gate pressure way too low, worn sprocket clamp spring, or take-up reel pulling way too hard), that's very unlikely to happen. However, the place I worked from '96 to '99 was an arthouse that regularly showed rough old prints (all changeovers), it was very rare to show the same movie twice, and we were expected to prepare each print for presentation in 30 minutes. When confronted with a 1960s print containing 20 suspect splices in each reel, it was simply impossible to inspect, and if necessary remake, all of them in the time I had.

The good news is that the FP-20 and its derivatives is insanely gentle on film if set up correctly, and the most tolerant of bad prints of any projector that I've ever used. The one gotcha is that if you back the gate pressure off enough to prevent it from pulling an old and failing cement splice apart, you run the risk that a tape splice that has been taped over 3-4 times will cause it to jump a perf on the intermittent sprocket; hence needing some extra wriggle room on the racking in that situation.

[Steve Pike]

Hey all

Thanks for all your comments. Some really good tips and tricks, really appreciate them all.

I had a spare moment this afternoon and attempted it again using the trick Randy mentioned about placing an X and a Star on certain frames. This, with a tiny adjustment, seemed to do the trick and certainly provided a quieter operation than the other day. I also made the top loop the same height as the feed sprocket and this also operated a little quieter too! Picture and sound was stable.

Will keep persevering, it's slowly coming back!! I suppose it doesn't help that the test reel of film consists mainly of ads and trailers from 1990s so older film which may be a little more brittle.

Talking of threading with eyes shut, I was able to (and probably still could) thread up a Westar/Westrex 2001 (Century) projector this way! It's been nearly 15 years since we used it but always seemed a much more robust and easier machine to thread.

Thanks all again

[Randy Stankey]

Go ahead and experiment a little.

You have a luxury that others didn’t. In an operating theater, you don’t have time to fiddle.
At a home installation, there aren’t any customers waiting for a show and there aren’t any managers looking over your shoulder saying, “What the hell are you doing?!”

Adjusting your loops by one sprocket, timing your intermittent differently or turning your frame knob a smidgen, one way or the other, might make a difference.

Every projector is a little bit different, even if it’s the same model. Each one can seem like it has a different personality.

You have to fiddle and tweak to find out how to make your machine work the way you want it to.

[Stefan Scholz]

Not really that good, but hope it helps.
The loops are not that critical. If too small, you can't use the full range of the framing adjustment. But actually, a projectionist knows about the existence, but never has to touch that adjustment.

https://1drv.ms/v/s!AnBc1nDZ8AU3he1w...m5JFA?e=0FkuLV

[Frank Cox]

Of course a projectionist needs to know how to adjust the framing. Sometimes if it's set too high you'll see microphones, fuzzy edges, etc; set it too low and you're cutting everyone off at the eyebrows. I don't know about the prints that you guys got, but mine never seemed to be really consistent between movies with regard to framing.

My framing horror story: The movie Seven. I got a copy of it that was chopped up like you wouldn't believe. I spent a whole day, morning and afternoon, going over that movie and fixing splices, and after all of that when I finally tried to play it there was still one out-of-frame on the fourth reel.
Since the show was coming up in the next half hour I just said the hell with it and stood ready to crank the knob when that splice went through.

(And yes, I still remember that it was about five minutes into the fourth reel. Can't remember what the scene on the screen was, though; I just listened for the click.

[Phillip Grace]

Hello Steve. You mention that the machine makes a "loud clackerty sound" when it is running. It could be that the gate tension requires adjustment. There will be a control knob on the front of the projector to enable this. Different types of film stock require differing degrees of tension in the gate to achieve a steady image on screen. The loud noise is associated with too little tension on the film. The picture on the screen will be seen to be jumping up and down. The correct adjustment for gate tension is to set it to the minimum required to achieve a steady image. Most films will run properly without adjusting the gate tension from its normal setting but there are enough variations in print condition that there are occasions when the projectionist will need to intervene.

[David Ferguson]

That looks like a very nice lens you've got there Stefan! Can I ask what the focal length is?

[Don Furr]

Steve, Phillip mentioned the tension on the gate. I noticed from your second picture that the gate tension is set half way between plus and minus. My home theatre projector is a Kinoton PK60D. My gate tension for the most part sits on almost minus. I've adjusted it maybe three times in several years when the print I was running had movement up and down on the screen.
Example: my print of Jaws 3D requires the gate tension set half way between minus and the half way mark. If the gate tension gets too tight my Kinoton makes clacking noise. You might want to experiment with your gate tension control on the front of the projector. I would take it to the minus side and adjust more tension until the picture is steady.

[Randy Stankey]

I don't consider gate tension to be a "set it and forget it" kind of thing.

Gate tension is something that needs to be checked almost as much as focusing the image. Once set correctly for a particular film it should be pretty stable but it is important to be aware of the film tension setting and the operator should be prepared to tweak it whenever it needs to be.

Acetate film is thicker than polyester film. Each will require a different setting.
Different manufacturers may produce films at different thicknesses and even different products from the same manufacturer might be different.

Projector condition and cleanliness can affect the way film runs through the machine. A dirty film gate can easily cause your film to run badly, making it look like you have a gate tension issue when, in reality, your machine just needs a good cleaning.

When I was servicing theaters for Cinemark, I had a few theaters that I knew weren't taking care of their projectors very well. They would call me up, complaining that movies weren't running right and the first thing I would tell them is to clean the projector and call me back. Even then, I would go to the theater to see a dirty projector with the tension knob turned all the way to the end of its travel and the movie was running like crap. I would clean it, thread it up and reset the tension. The movie ran perfectly.

Invariably, the people at the theater would say, "Wow! That's great! How did you do that?"

I just said, "I cleaned the projector like I told you to do, yesterday!"

Also, lubricating the projector gate runners and/or the film will require the gate tension to be changed.
I have had a couple of instances where the projector was running badly during a show on a busy Saturday night.
Of course, you can't stop the projector to clean it so you have to do something fast.
I would get a little bit of film and projector cleaner/lube like XeKote on the end of a Q-Tip cotton swab and touch it to the top of the gate, right where the film is entering. This isn't the best thing but it will get you by in an emergency, long enough to finish the show. Then you can fix the problem correctly.

Point is that lubrication can change the way the projector runs and require changing the gate tension.

Bottom line: If you take care of your projector, you shouldn't have to mess with gate tension a whole lot but it IS something you need to be aware of and occasionally tweak.