Film-Tech Forum ARCHIVE: Larger hub or more tail?

This is topic Larger hub or more tail? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Thomas Jonsson (Member # 1902) on 04-18-2004, 10:26 AM:

I run change-over with 6000 ft reels with a 6 inch hub.
Sooner or later the end of the reels get "rainy", no
matter how much you keep the projector and booth clean.
What´s the best way to prevent this - add more tail at
the end of the reel or get reels with a larger hub?

Thomas

Posted by Gordon McLeod (Member # 33) on 04-18-2004, 10:32 AM:

Both are a good idea as well as controling rewind speed
highspeed rewinding can cause the film to slip against itself when the reel stops causing the cinch marks

Posted by Scott Norwood (Member # 30) on 04-18-2004, 10:36 AM:

Are you using fixed-hub or floating-hub reels? You shouldn't have problems with cinch marks if you use floating-hub reels (for both feed and takeup) and a rewind bench with an adjustable speed control that can be regulated to avoid fast starts and stops. Adding extra head and tail leader is, of course, a good idea regardless.

No doubt that Brad will post here soon to extol the virtues of Christie platters. [Smile]

Posted by John Walsh (Member # 168) on 04-18-2004, 11:13 AM:

You might try increasing the take up tension to reduce the film from sliding, but don't over-do it. Don't use rewind table shut-off arm rollers that ride on the film (like a Kelmar.) Wrap junk film around both the feed and take up reel hub to increase the diameter (the film can get really stretched as the projector tries to pull film off of a small diameter feed reel.) Go easy on rewind speed, and slow it gently down before it comes off the end.

Posted by Thomas Jonsson (Member # 1902) on 04-18-2004, 11:13 AM:

It´s wire spools with fixed hubs. The rewinder has variable speed, and rewinding is very slow. Friction on both projectors
and rewinder are as little as possible. Still this annoying
"rain" occour now and then.

I want to get rid of this - but what´s the best solution: a
larger hub or more tail. Or is the result the same?

Thomas

Posted by Floyd Justin Newton (Member # 1316) on 04-18-2004, 11:25 AM:

Thomas---

There is a product called 'Film Guard' that's available
throughout the world. Just 'click' the Product button to
the left.

fjn
Local 294 Ret.

Posted by Bruce Hansen (Member # 281) on 04-18-2004, 11:25 AM:

Do you happen to use film guard? It may help. (It works on water skis as well [Big Grin]

).
Be sure to keep the film clean, don't let the leaders hit the floor.

Posted by Steve Guttag (Member # 268) on 04-18-2004, 12:43 PM:

As to eliminating the "rain" that is almost exclusively the result of insufficient protective leader at both ends of the reel.

Going to larger and floating hubs will minimize potential damage on start ups and rewinds since only the hub must be broken from static friction rather than the whole reel (spool).

What I have done since the era of disposable previews (Trailers) is to recycle them into scrap leader...Be generous...add a minimum of 15' to both ends and ONLY handle the film by the scrap leader...splice it in frame and thread up on that...then wind the projector down to the count down...don't touch the film past the "ID" section. The dirt you keep off by following the above procedures will eliminate the streaks you see.

As to Film-Guard...it will keep the whole shebang clean...beginning to end. However, it is not subsitute for keeping your fingers off of the film. When you send that film out...pull off your scrap film and throw it away and put new scrap film on the next feature...one should not be able to tell you handled the film at all.

Steve

[ 04-18-2004, 05:23 PM: Message edited by: Steve Guttag ]

Posted by Brad Miller (Member # 2) on 04-18-2004, 02:12 PM:

I agree with Steve that the biggest problem here is insufficient head and tail leader. Steve recommends 15 feet extra at each end (that's in addition to the lab leader), but my minimum is 25. If you are threading on the actual lab leader and/or have not added extra junk leader on each end, you are creating those cinch marks (rain) because of it.

Posted by Thomas Jonsson (Member # 1902) on 04-18-2004, 02:42 PM:

Thanks for all replys. So larger hubs won´t do the trick, then?
It´s the added junk leader that does it. I will certainly try it.

As for FilmGuard - any dealer in Scandinavia?

Thomas

Posted by Bevan Wright (Member # 1884) on 04-18-2004, 10:05 PM:

Always go for 'more tail'..... sorry, obvious softball and no one was taking a swing at it. [Roll Eyes]

Posted by Phil Hill (Member # 371) on 04-18-2004, 10:38 PM:

Some always go for a 'larger hub'.... sorry, obvious hardball and no one was taking a swing at it. [Razz]

(With apologies to Bevan for twisting his words into mine...) [Big Grin]

>>> Phil

Posted by Peter Kerchinsky (Member # 1098) on 04-19-2004, 05:02 AM:

To avoid "rain" on prints.....
dump the 6000 foot reels and
get Christie platter.
All those ideas suggested in earlier threads have been tried here to no avail. The prints still have the "rain" or whatever at both the start of the film, the reel change, and the end.
Expect it with reel to reel, especially when you run many showings.
Sorry Brad that I may have beat you to the punch on how good Christies are on film handling. No worries here, mate!

Posted by Stephen Furley (Member # 1277) on 04-19-2004, 05:46 AM:

Shouldn't have this problem running reel to reel, even after very long runs. Correct tension, neither too high nor too low is important, both when projecting and rewinding. don't let the end touch the floor.

Rewind slowly, I generally do it at about 2-3 times running speed if using a powered rewind bench, slightly faster on hand ones to avoid spending most of my time rewinding film.

I like a long enough tail on the film that I can spend a couple of seconds to check, and if necessary adjust, the picture after a changeover, then walk to the other machine while the film is still running through. I press the stop button just before the end, so that it comes through, as the speed runs down, and I can grab the end, to prevet it dropping on the floor. If the spool is still turning, it's important not to hold the end still, so you are pulling on the film, but to follow round the rotation of the spool with it. If the machine stops before the film has completely run through I just inch the last bit through by hand.

I find the most wear/damage to prints is cause by making up/breaking down, rather than by projection or rewinding. If you've got a print that's been made up and broken twenty, thirty or more times, and only run a few times at each location tends to be in much worse shape than one that's been run hundreds of times, without repeated making up and breaking down.

Posted by Gordon McLeod (Member # 33) on 04-19-2004, 09:27 AM:

Rewind tension and speed are very important
For years in our old 3d theatre at ontario place we used drypur rollers on the rewind bench to clean and also maintain even drag on the print during rewind and we would typicall run 2000' passes during a summer on asingle print with no rain

Posted by John Pytlak (Member # 331) on 04-19-2004, 10:48 AM:

I agree with Gordon that keeping the film clean, and avoiding any cinching from loose rolls or uneven acceleration will prevent any "rain" or cinch marks. Before "loop" and bi-directional printing, labs could get many hundreds of prints from a printing negative that was rewound each time it was printed.