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Topic: Horizontal Lines on Screen?
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Maurice Leakey
Film God
Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007
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posted February 02, 2008 09:38 AM
Steve
I worked all my life as a 35mm projectionist and latterly used cake-stands (platters) and never experienced horizontal scratching. Film on platters whilst moving sideways actually goes through rollers in a vertical position (sideways vertical - if you see what I mean.) Green prints are always a problem with build up of new emulsion often clogging the gate and causing vertical scratches. In the old days gates were cleaned after every 2000' change-over, now its 15000'!
Scatching as you describe could possibly happen in the UK and other countries which still ship 2000' rolls on cores, if a roll is loosely wound and hardly fits into its can, a projectionist (God help him) might force it to fit, thus causing vertical (i.e. horizontal on screen) scratches.
This, however, is unlikely to happen in the USA as films are still shipped on 2000' spools, three to a six-sided transit case. At least, they were last time I was in the USA, some ten years ago at the Hollywood Galaxy.
However, this doesn't really answer your question and it would be interesting to hear from a US projectionist used to platters and their possible problems.
Maurice
-------------------- Maurice
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Hugh McCullough
Expert Film Handler
Posts: 156
From: Old Coulsdon. Surrey. UK
Registered: Oct 2006
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posted February 06, 2008 11:28 AM
Yes Maurice, I know that all rewinders have a tension spring to supply a certain amount of "drag".
The only use of fingers is to not only to locate a splice, but also any damaged sprocket holes, and to help the film run onto the spool in an even manner.
What causes scratches is if the film is twisted by the fingers so that the emulsion rubs against the rim of the spool.
You state that you have been a 35mm projectionist all your life. How long is that?
I have been a professional projectionist for 49 years, did a four year apprenticeship, sadly these are no longer in existence. Have run 16mm, 17.5mm, 35mm, and 70mm, both married and unmarried prints.
-------------------- EIKI Ex 6100 xenon machine.
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Graham Ritchie
Film God
Posts: 4001
From: New Zealand
Registered: Feb 2006
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posted February 06, 2008 09:17 PM
Hugh Your web site is very good, sadly out here many cinemas like the Cinerama have all gone, what is worse there is no known photo record of many of them, your projectionist survival kit was interesting, a little bit different to the one Peter Sellers used in "The Smallest Show On Earth" here is a couple of photos of my version of a wrap-detector.
I made this one for the "Kinoton" this is the MK1 model more to follow the MK2 for the Bauer and Simplex having a wrap-detector on the platter in this cinema is not practical due to number of films coming and going in all directions, it protects the projector from damage that might occur using polyester film and is fitted right next to the projector, took half a day to make it in the garage.
In the event of the film coming under tension, it pulls the lower assy out of a spring loaded latch, at the same time the micro-switch on the left, which is wired to the computor shuts the projector down, most of this stuff was bought from a local hardware and aluminium supplier, except for the rollers and switch. allowing for a projector run down period this is were the film stops, with no strain to the film and most importantly no damage or excess load to the projector, I have tested it out and it works great, I wonder if I should go into business?.
Graham.
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Patrick Walsh
Jedi Master Film Handler
Posts: 723
From: Christchurch, New Zealand
Registered: Jul 2006
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posted February 07, 2008 02:30 AM
Graham's wrap dector is very good and yes would recomend making / selling more! speaking of platter scratches those new films at work 2 of the 3 have platter scratches, one (Priceless) so bad made up other copy to run, big green scratches down the centre and horizontal scratces all the way through comming almost half way across the screen, the other (death at a funeral) has minor markings all the way through on side of image. There must be many ways films can become scratched either using reel to reel of a platter system, no system is without its problems but if it has been installed and set up right and has been looked after and the machine cleaned every thread-up and the film path checked you should not have any problems. all films do get a bit knocked around about after a while especially 35mm, going from one theatre to the next, being run on platters , reel to reel, towers etc. Hugh your website is very good, nice to see some images of a Kalee 12, I used to have one of those here at home, using a very old NZ made "Realtone" soundhead that mounted out the front of the head just beneth the lower sprocket, looked like a piston head from a motor cycle engine, ran very well but had to sell as I was in short supply of the old $ Now have a Ernemann II machine from 1920s Germany a workhorse and some are stll in commercial use today, they were front shutter and when scope came out you could buy a conversion kit to change them to a drum shutter so a cinemascope lens could hang out the front.
Pat
-------------------- "Raise The Titanic!", It would of been cheaper to lower the Atlantic!
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Bill Brandenstein
Phenomenal Film Handler
Posts: 1632
From: California
Registered: Aug 2007
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posted February 09, 2008 11:00 AM
My vote goes to David's conjecture - mis-threading of a roller on the takeup platter. The markings were consistent on every part of the show - ads, trailers, feature - and ranged from light black to intermittantly slightly green. So not as likely to have occurred when building up the show, or from flange binding (too consistent, too frequent in this case). The print was first-run and about 2 weeks old.
Graham, I can't explain the lack of DTS backup. But this is part of what makes me so frustrated, is the apparent lack of care/concern. Perhaps competence too, but other times this place has been spectacular. Ratatouille was amazing (and loud -- you should have heard the thunder clap. We jaded moviegoers came out of our seats) with a picture quality that could send digital cinema packing at full speed down the street (flawless).
Maurice, Graham, Hugh, Patrick, and David (am I missing anyone else?): this has been a fascinating read. Thank you!
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