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Author Topic: Loose static clinging prints on Christie?
Tommie Evans
Expert Film Handler

Posts: 116
From: Birmingham, West Midlands, UK
Registered: Sep 2004


 - posted 09-28-2004 02:06 PM      Profile for Tommie Evans   Email Tommie Evans   Send New Private Message       Edit/Delete Post 
I am having problems with a Christie platter [Frown] . The film feeds on loosly (you can wobbly the layers of film in the roll) and when feeding out again is subject to static and forms an inward bump in the print.
I have re-timed the platters by following the instruction manual closely and all LED/LDR, Intensity and control cards have been re-newed. I believe the problem is the platter arm return springs. Do I replace them or cut them shorter so they are under more tension? The platter is over 7-years old now [bs] , would it be best to simply replace all three arm springs and also the springs for the feed control arms.

The problem occurs on all three decks, so is there adequate electrical grounding on the system - if not how and where do I check?

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99


 - posted 09-28-2004 03:06 PM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
What is the year date of manufacture? Also, have you tried running a different print on it?

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 09-28-2004 03:10 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
Your really loose rolls sounds more like a tensioning problem, but it may be making the payout very sensitive to slight static charges between the laps of film.

Before Kodak introduced KODAK VISION Color Print Film with its transparent conductive antistatic layer or Brad introduced FilmGuard, I wrote the following article to help theatres deal with "static cling":

Help for Static Cling

quote:
KODAK: Help for Static Cling - Print Friendly Version
Help for Static Cling
Question: Last winter, we had a lot of problems with static cling, where the
film tends to stick together as it goes into the "brain" of the platter. We had a
few jams, and even had the last reel of the print slide off the platter when the
speed got out of control. What can be done to control this problem?
Answer: First, use an accurate digital humidity gauge to measure the relative
humidity in the projection room. (Radio Shack and Edmund Scientific have
suitable digital hygrometers for less than $30). Adjust the HVAC or use
portable evaporative humidifiers to keep the humidity between 50 and 60
percent. Don't use humidifiers that actually spray water droplets into the air,
as they will leave behind a white dust from the minerals that are in tap water.
Be sure all equipment is properly grounded. Generally, platters and film
handling equipment with conductive surfaces are less prone to static buildup
(measure resistance to ground with an ohmmeter). Treat non-conductive
materials (painted or anodized platter surfaces, plastic rollers, etc.) with Static
GuardTM or other anti-static chemicals to increase conductivity. In extreme
cases, the print itself can be treated with Static Guard. Some projectionists
have found that active ionization units (e.g., Kinetronics StaticVac TM Film
Cleaner, Staticmaster TM brushes, or corona discharge ionizers from Simco or
Meech) are effective in controlling static build-up on the film. The best place to
use them is between the projector and the platter take-up, so static is
removed just prior to windup.
We have found that winding orientation can affect how easily the film pulls an
adjacent lap into the "brain" of the platter, depending upon the curl of the
film. If you normally wind the film on the platter with the soundtrack side up,
try winding it with the soundtrack side down (or vice-versa). Static cling is
usually most apparent during the later reels of longer pictures, since the film is
coming off the inside of the feed roll at a very shallow angle, allowing static to
attract adjacent convolutions of film. That is why long movies are most
affected.
Kodak has always recommended the use of a tension-sensing fail-safe that
shuts down the projector in the event of a platter jam or brainwrap. Always
use sufficient platter clips (suction cups) around the outside of the feed roll to
prevent it from getting off center or sliding off the platter due to "static fling."
Another device that helps prevent film jams and sliding film rolls is the Non-
Slip Platter Disk (patent applied for), sold by Projection Technology, Inc.
(phone: 516/576-0767). This unique invention by projectionists Stuart Boritz,
Edmund Nardone, and Andrew Fetherman fits on the platter surface, and
although it doesn't eliminate static cling, it helps separate the film laps if they
stick together, and provides a non-slip surface so the film roll doesn't slide.
The best news is that Kodak has just introduced two new color print films
which feature an anti-static backing layer. We are working with film
laboratories to incorporate an anti-static process additive in the final rinse of
the process. Testing shows that the combination of the new films and antistatic
process additive will almost com-pletely eliminate "static cling." The new
Kodak Vision print films also reduce static attraction of dirt to the film, so
prints should stay cleaner. Projectionists will also welcome the elimination of
annoying static "shocks" as they wind and handle film during inspection and
make-up onto the platter.


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Ramin Hashemi
Expert Film Handler

Posts: 129
From: Houston TX
Registered: Sep 2004


 - posted 09-28-2004 09:44 PM      Profile for Ramin Hashemi   Email Ramin Hashemi   Send New Private Message       Edit/Delete Post 
I used to can get rid of static using dryer sheets (with little success). But ever since I replaced the middle roller of the brain with a metal one, I have had no static issues.

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Dean Kollet
Jedi Master Film Handler

Posts: 591
From: Florida State University
Registered: Jul 2003


 - posted 09-28-2004 10:21 PM      Profile for Dean Kollet   Email Dean Kollet   Send New Private Message       Edit/Delete Post 
try another print....even a trailer pack or something

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Tommie Evans
Expert Film Handler

Posts: 116
From: Birmingham, West Midlands, UK
Registered: Sep 2004


 - posted 09-30-2004 07:19 AM      Profile for Tommie Evans   Email Tommie Evans   Send New Private Message       Edit/Delete Post 
The problem happens to every print placed in that screen and then the static problems continue when that print is moved to another platter system.
I have cut the top platter spring in half so it feeds on under more tension, which has helped - probably best if I replace all three arm springs!!
Where is the best place to check that the platter is properly grounded?

regards Tom...

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John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 10-01-2004 03:55 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
If your electrical code allows it, run a separate ground wire between the metal platter frame and a good ground like a metal cold water pipe. But normally, if the platter power cord has a ground terminal, that is adequate.

Keep metal surface platters clean and free of oxide and oily buildup. If in doubt, use a topical conductive antistat on the platter surfaces and plastic rollers -- e.g., "Static Guard", "Staticide", "Neutrostat", "No-Stat-X", etc.

Even though Kodak VISION Color Print film has a conductive backing layer, it is most effective when there is a path to ground.

But it still sounds like loose tension is causing most of your problems.

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