Film-Tech Forum ARCHIVE: Grip Tape on Platters?

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Posted by Jeff Akin (Member # 1198) on 05-01-2002, 07:13 PM:

I am helping with the integration of one of the UA theatres into the Regal Ent. Group. This particular theatre is an older, 40's style theatre...really nice.
They have older Christie platter systems. When I walked into the booth, I saw that the prints were sitting on grip tape that was on the platters. The projectionist said it was to keep the prints from sliding off of the platters.

Is this a good thing...or a bad thing?

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2 Time ICWF Champion

2 Time ICWF Hardcore Champion

Posted by Brad Miller (Member # 2) on 05-01-2002, 07:42 PM:

I can see where the theory lies and it probably does work, but oh boy how messy will that tape get over time???

The best solution is posted in a page on Christie platters in the "tips" section (of which I desperatly need to update). Just look for the part in there about "grooving" the platter decks.

For those people with decks that can not be grooved in this manner (say SPECO and Strong for example), Kelmar is now selling a blue rubber mat which looks interesting, but I have not personally tested it so I hesitate to definitely say it works well. There are also other solutions like the round sheet of hardwood with asphault strips on them, but I do not like those for they constantly bump the feed arm and I wouldn't want the edge of my prints dragging over what is essentially sandpaper. (Although in all fairness I have heard positive reports from the field.)

Posted by Darryl Spicer (Member # 711) on 05-01-2002, 09:54 PM:

Hold up on that. You say these are the older Christies. Are we talking about the ones with the formica counter top finishes on the decks. They like to throw prints just by looking at them. If these are the ones that is probably why they have that tape on there.

Brad, those boards with the asphalt strips I have at my theater. I used them once, then decided never to use them again, because on the speco platter systems I couldn't get the film to ride on them properly, and that was after adjusting the takeup roller as high as it would go.

Posted by Aaron Sisemore (Member # 145) on 05-01-2002, 10:18 PM:

Pacific Theatres routinely uses eight radial strips of electrical tape on their AW3 decks to keep the prints from sliding.

We bought several AW3's from them about a year ago and I spent the better part of a couple hours peeling tape from the decks and cleaning the decks (FilmGuard to remove the adhesive goo, followed with soap and water to clean the FG residue)...

-Aaron

Posted by Jeff Akin (Member # 1198) on 05-01-2002, 10:57 PM:

The old, metal Christies. I can see where the prints would slide like crazy. I'll look into 'grooving' the platters.

I screened their new print of Jason X, and it looked fine. Then, I screened a little bit of Clockstoppers that they have had for a little over a month. There were some pretty nasty scratches on the non-soundtrack side of the film--right side on the screen. So, I suppose those could be from the grip tape...but then they should have been on the Jason X print too.

Oh well, thanks for the advice. I'll pass it on to the GM there and we'll see what we can do.

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2 Time ICWF Champion

2 Time ICWF Hardcore Champion

Posted by Paul G. Thompson (Member # 655) on 05-02-2002, 01:05 AM:

Something strange here.

I have 5 each AW3's in Stanwood, and I never saw these machines come even close to throwing a print. Of course, these platters are badly scratched from previous operators that apparently did not care about taking care of the equipment.

However, I have 3 each A-3's in Anacortes that get a little tempremental, and the film does shift off center sometimes. Perhaps a re-time would take care of that problem. I use microswitch pay-out heads which are the absolute worst for stability, but the best for reliability. They do like to "whip" upon contact closures of the micro-switch.

I have 3 each CFS machines in Oak Harbor. These 20-year old machines are more forgiving about "whipping" since they had a ballast resistor (I think it is a 10 ohm 25 watt rating, and this resistor is physically inside the motor housing) across the micro-switch contacts. But they were much more critical in timing. As old as they are, they seem to run fine for the most part. I seldom have reports of the prints shifting off center, but I would guess that has something to do with the steep crown the platter decks have.

For years, I had ran a bunch of older Xetron platters (the XNR series) and never had a problem of any kind involving tossing or shifting prints.

As a note, many projectionists/operators blame the pay-out head for feed problems, such as they won't stay up with the demand or they overshoot and hunt excessively. With the A-3's, (Strong and Potts) the CFS and old Potts and Potts-built ORC's, the problem may not be with the pay-out head. It is more often the take-up causing the problem.

How could that be?

Simple....The take-up dancer controls the variac which in turn sets up the operating voltage for both the take-up and pay-out motor. If the dancer is riding high, the pay-out will probably fall behind and cannot stay up with the demand. If the dancer is riding too low, there may be excessive over-shooting and hunting. Now that will enhance the danger of the print leaving the platter dish and throwing itself on the floor, bashing the pay-out head to smithereens in the process.The only thing I can think of is when an AW3 tosses a print, it is because there was a control module failure that would allow full power to the drive motor.

AW2's or AW1's, are obsolete. I don't think Christie supports them anymore. If that be true, junk them out when they start giving you headaches.

So, what are there so many problems with platters throwing prints? Are people waxing their decks to make them look real pretty? If they are, they will definately toss the print on the floor.

Maybe the projectionists or operators are they using the wrong formula to keep the decks clean.

The light bulb is on.....Input, please.

Rant Mode off.....

Posted by Adam Wilbert (Member # 1184) on 05-02-2002, 01:52 AM:

Paul, I've been putting on two coats of wax every three months. Is this not right?

Seriously though, I've never had a problem with the CFS platters throwing a print. But they do have a lot slower "reaction time" than the Christie AW-3's i've used in the past. So much so, that we usually try and kick-start the platter by hand when starting the film, rather than just letting the film wrap around the brain before unwinding. Once its up and running though, there isn't much of a problem.

Paul, what did you mean by "I would guess that has something to do with the steep crown the platter decks have"?

-Adam

Posted by Paul G. Thompson (Member # 655) on 05-02-2002, 02:08 AM:

Adam, look at the outriggers under the dish. You will see the extreme end is bolted directly to the dish, and there are progressively higher cork spacers between the outriggers and the dish as you approach the hub of the platter.

If you use a straight-edge, you will observe a crown in the dish almost 3/8 of an inch difference form the center and the edges. If you use the "Ole Eyeball" method, you can still see the crown.

As far as helping the platter along on start-up, I have mixed feelings about that. The only thing I don't like about doing it that way is that it does not give enough time to insure the focus, mis-frames (lots of those in Oak Harbor), etc.

Have faith in those platters. They will take care of themselves, and just make sure things are looking correct on the screen.

Posted by Brad Miller (Member # 2) on 05-02-2002, 06:54 AM:

I would have to say that the original SPECO LP270 is probably the best platter on the market for never going out of adjustment and never throwing prints. The motor is so sluggish to get up to speed that while it does do a handy wrap around the backside of the brain and scratches the first 20 seconds of the first trailer, once it has finally gotten itself up to speed, it's virtually impossible for it to throw a print. I wish more platter manufacturers would understand the importance of sluggish response to the payout arm. I've had far too many problems with microswitch based platters that I don't have anything nice to say about them and I take great enjoyment in un-installing them every chance I get and putting a Christie or SPECO in it's place. SPECO's LP270 is the only platter to use an on/off type of design that actually works well.

And that right there is why the Christies if not properly timed will throw a print through the wall. All it takes is a tiny knick in the platter to grab at the film during payout (which is of course worse as you get toward the end of the movie) and the arm will swing violently from say the 20% speed it was running happily at and slam all the way over to 100%. Whip, slide, kachunk, oh shit! This is why I do not like the timing instructions in the Christie manual. The platters run too jerky when they are timed that way. If you time them my way and groove the decks, I think you will find that print tossing on a Christie will be a thing of the past.

P.S. the new "auto-timing" kit that Christie is putting out is crap. They WILL hurl prints on you! It is impossible to achieve the smoothness of the old graduated filter and led with this new infared/linear "upgrade". I know some people like them, but I find they make the problem worse.

Posted by Bob Maar (Member # 763) on 05-02-2002, 08:20 AM:

Their is a company on Long Island that makes a disc to fit onto your platter and ensure that your film will stay in place. Their is a link here on film-tech. Or you can call Stu Boritz at 1 516 972-5078. I used thier "Platter Disc's" when I was at Loews and they solved our problems. www.projectiontechnology.com These discs were invented by projectionist's for projectionists.

Posted by John Pytlak (Member # 331) on 05-02-2002, 09:43 AM:

Prior to Kodak's introduction of VISION Color Print Film (with conductive anti-static backing layer) and Kodak's development of an anti-static process additive for prints, I wrote an article that also noted the "platter disk" Bob Maar mentions:
http://www.kodak.com/country/US/en/motion/newsletters/reel/september98/pppp.shtml

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

Posted by Brad Miller (Member # 2) on 05-02-2002, 03:25 PM:

Yeah that's the discs I played with a couple of years ago. But $390 for one platter system??? I had no idea they were that costly. Anyway, for what it's worth, the gripe I got from them was that it was abrasive to the picture edge of the film and caused the payout to constantly speed up and slow down and increased print shedding. I only played with them for one day, so I can't confirm or deny those complaints 100%. Maybe someone will send in a loaner pair to review.

Posted by Matthew Bailey (Member # 601) on 05-02-2002, 06:09 PM:

I think the use of a platter deck mat made of sheet velvet or pool table fabric fastend to the deck with Velcro tape would put an end to scratches when disassembling or building up a print.

Posted by Ken Lackner (Member # 1002) on 05-02-2002, 08:09 PM:

Although I've only used them for one day now, it seem like the Big Sky platters have no trouble getting up to speed right away, and the film does not wrap for the first few seconds. I plan on doing a review once I get some more experience with them.

Paul, why do you say the microswitches are the worst for stability? I thought you liked them.

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This one time, at Projection Camp, I stuck a xenon bulb....

Posted by Paul G. Thompson (Member # 655) on 05-02-2002, 08:13 PM:

Ken, I do like them. Seldom do they fail.

Never tossed a print yet with them over a 20 year span....

Even if the micro-switch set-up tossed a print on me (0 times in 20 years), I would still prefer that record rather than all the shows lost over the same period of time due to some damned electronic-based linear pay-out control deciding it is time to go to lunch.

I wonder if the high failure rate of the linear controls might be due to under-design and surge current when switching the motors on and off with the dancer raised? Or, even worse, raising the dancer before turning off the motors....That should be looked into. That is one helluva surge if, for some reason, the pay-out arm is flopped to the full-on mode when the dancer is raised.

Engineers like Steve Guttag as well as others might be able to calculate the strength of the surge, and whether or not the triac or SCR (or whateverthehelltheyuse)in those whimpy pay-out controls can handle the hammering.

Maybe it is also due to the LED's losing their poop like some basement digital basement readers....

I find it sort of odd that those linear pay-out head controls have a relatively short life as compared to the micros.

Posted by David Favel (Member # 1125) on 05-02-2002, 11:53 PM:

Yea, I have an original LP 270

Never had any problems tossing a print & the only problem has been the one Brad mentioned.

My 1 question is can you buy the new rollers as seen on the review page?

Posted by Paul G. Thompson (Member # 655) on 05-03-2002, 12:43 AM:

The LP-270 is a fine machine.....but keep the WD-40 off the twist rod and its guide.