Film-Tech Forum ARCHIVE: Static!!!

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Posted by Sean Thompson (Member # 105) on 01-23-2000, 11:19 AM:

We have been having a problem with static in our booth and we were thinking it could be the humidity or the temp. It has been staying pretty warm and dry up there and i was wondering what the best humididty and temp should be?

Posted by Ken Layton (Member # 133) on 01-23-2000, 12:19 PM:

Get some Filmguard-----NOW!

Posted by Gordon McLeod (Member # 33) on 01-23-2000, 01:47 PM:

The tempertureshould be between 60-70 f and relative humidity of 65%

Posted by Mike Colley (Member # 327) on 01-23-2000, 01:50 PM:

Humidity in the booth should be between 50% and 60%. If you have doubts, get one or more hygrometers(depending on the size of the booth) from Radio Shack. They run about $20 each. If you do see the need for extra humidification, I've gotten pretty good results from the Emerson portable humidifiers. With regular maintenance, changing filters and using antibacteriostatic water treatment, they can last a pretty good while. I've found them at Grainger. If you can't locate the Emerson models, just make sure that it is the evaporative type of humidifier to minimize corrosion to your equipment. By the way, Filmguard does work as well as everyone claims. The theatres that I have tested have eliminated static problems in the prints treated. Good luck!

Posted by Bruce McGee (Member # 131) on 01-23-2000, 04:20 PM:

Ken said it best.

Get the FilmGuard. The static will be gone, your prints will look better, and your projector will run quieter.

And it smells good, too.

Posted by Dave Williams (Member # 299) on 01-23-2000, 05:18 PM:

Oh yeah, love that film-guard. Has that high school shop smell that I used to love.

------------------
"If it's not worth doing, I have allready been there and done it"

Posted by Masao Garcia (Member # 184) on 01-23-2000, 10:58 PM:

I've been told that Kodak prints are treated with some sort of anti-static spray type coating to help reduce static. Does this coat tend to wear off? Because the Green Mile at our theatre has mucho static at the last reel. The Hurricane also has developed a bit of static at the end and "brain" wrapped today. I know some people here don't like the term, "brain", but I use it cuz I didn't learn any better. At least I put it in quotes. And as for going out and buying Film Guard, I work for Cinemark, so we all know that story...

Posted by Randy Stankey (Member # 64) on 01-24-2000, 04:20 PM:

I agree. Get FilmGuard.

We used to have film interruptions almost DAILY!

Last winter, there were several films that had to be baby-sat almost all the time!

[i]Jackie Brown[\i] wrapped 3 times in a row! You'd fix the first one and restart the proj. and it'd wrap 2 minutes later!

S.W.Ep. 1 would wrap at the same place in every show. We'd actually set the timers on our watches and go to the platter when that spot went through.

We got FilmGuard and we have had ZERO wraps. Not one!

If your company doesn't have F.G. in stock, just use petty cash to get it. If the corporate monkeys try to nail you about it, just show them the rain check logs.

In July, we averaged 3-5 interruptions per month. That average was taken over the last two years. Now we have FilmGuard there have been 7 interruptions in since October. Four of them were becasue of mechanical breakdowns. One of them was because of a manager's mess-up.

Basiaclly, if you don't have FilmGuard, you ought to get it!

Posted by John Pytlak (Member # 331) on 01-25-2000, 08:58 AM:

Kodak refined the formulation of its proprietary anti-static backing technology when the company developed its new generation of Kodak Vision color print films in 1998. We also developed an anti-static process additive that labs can add to the final wash in the print film process. Kodak began providing this additive ("Staticide 3000G")at its own expense to film laboratories around the world in early 1999. It helps reduce "static cling" on all print films, even those not manufactured by Kodak. Further improvements are underway.

In the past year, reported incidents of "static cling" have decreased substantially because of these improvements. However, a few prints may still be prone to "static cling" under certain conditions (e.g., non-conductive platter surfaces, if there were variations in the amount of "Staticide" applied to the print, or changes in humidity).

As noted by other posters, proprietary film treatments may help reduce "static cling", either by increasing the conductivity of the film, or by "balancing" the static charge between the emulsion and base side of the processed film.

For help on reducing "static cling", see the article in the September 1998 "Film Notes for Reel People":
http://www.kodak.com/US/en/motion/newsletters/reel/september98/pppp.shtml

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Professional Motion Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com

Posted by John Pytlak (Member # 331) on 01-25-2000, 02:55 PM:

To: Masao Garcia
I note that in addition to your recent "static cling" incidents, you have had ongoing static problems in the past as well. I see that you are from Lancaster California, in the middle of the Mojave Desert. What is the typical relative humidity in your projection room? Does it get especially low in the winter? Any hope of using humidification to increase the humidity closer to the recommended range of 50-60 percent RH?

Posted by Tim Reed (Member # 137) on 01-27-2000, 01:00 PM:

Gentlemen and Ladies:

Wouldn't it be easier to simply return to acetate?

There's been thousands of dollars of equipment damaged by this Estar stock, because of its unsuitability for platter projection (to say nothing of the countless man-hours expended repairing these mishaps, the interruptions to business, and resultant ill-will generated among customers).

If theatres still ran on reels, there'd be no problems with implementing Estar, but the industry is several decades removed from that now. Dupont tried a polyester base film in the early 50s, after the demise of nitrate stock. Fortunately then, it could not be easily spliced, so it did not gain favor.

Everyone's been doing a lot of backpeddling, trying to make a dielectric material behave like it's not a dielectric. That's why they make capacitors out of polyester.

With all due respect to Mr. Pytlak, shouldn't Kodak just forget about Estar and concentrate on improving acetate, given that improvements are the objective? I know many people would agree that Estar is anything but an improvement. Besides, all good ideas aren't necessarily good ideas. Everyone is entitled to make a mistake from time to time. And Kodak, with all the good work and research they've done over the years, would be due for at least this one.

I'm sure the industry would forgive them if Estar was discontinued.

Posted by Brad Miller (Member # 2) on 01-27-2000, 01:15 PM:

Well said Tim! I wholeheartedly agree with the return of acetate. However, I don't see it happening. Perhaps our good friend John Pytlak can explain all the reasons the industry switched to polyester for us. I can think of no one better to do so.

Posted by Erich Loepke (Member # 166) on 01-27-2000, 01:54 PM:

Speaking of past mistakes, how about Eastmancolor?

Also, did Kodak produce regular Eastman stock and SP simultaneously? I have a 1981 print that's on Eastman film stock, and does not have SP on it anywhere.

Posted by John Pytlak (Member # 331) on 01-27-2000, 03:35 PM:

Kodak did NOT lead the charge to polyester film, and publicly urged caution regarding issues like its tremendous tensile strength, electro-static properties and potential for "flaking" when severely abraded (Report to Intersociety Committee at ShoWest in March 1994).

But distributors and exhibitors demanded it. The January 1991 NATO News reported: "The (NATO) board also resolved, at the (NATO Technical Advisory) committee's request, to approve and recommend the use of polyester film, which is thinner (allowing more film per reel) and less liable to break."

From 1991 to 1995, most polyester prints were printed on other manufacturer's film (e.g., "The Fugitive", "Free Willy", "The American President", etc. Kodak moved slowly and cautiously in converting from triacetate to polyester print film for theatrical prints, and began an intensive program to develop new technology to address the issues of polyester abrasion and static. This technology was used in the new Kodak VISION Color Print films, supported by a massive investment ($200 million) in a new machine to make base for the new film. Kodak VISION Color Print film has greatly improved performance and quality, and additional improvements are underway. Triacetate base is no longer being used for release prints.

Posted by Brad Miller (Member # 2) on 01-27-2000, 04:12 PM:

That's good to know Kodak wasn't behind this polyester mess. However, if the studios were worried about fitting more feet on a reel, why do I keep seeing 8 reel prints that should be on 5 reels? It's getting worse and worse lately. Also, whatever happened to the ELRs? (I'm still squirming at the idea of a Technicolor ELR.)

Posted by John Pytlak (Member # 331) on 01-27-2000, 04:14 PM:

Erich:

Kodak spent many years developing the new stable dyes that were introduced in 1979 with EASTMAN Color LF Print film (7378) and EASTMAN Color LFSP Print Film (7379) at a slightly higher price (the dyes were much more expensive to manufacture). The older 5381 and 5383 print films continued to be sold until 1982, when they were replaced with EASTMAN Color Print Film 5384, which used the more stable dyes without a premium price. When properly processed and stored, prints made on Kodak film since 1982 show much less fading than previously available incorporated-coupler print films.

The "SP" designation refers to films designed for the "short process", that is, the higher temperature ECP-2B process, which co-existed with the original lower temperature ECP process at that time.

See the "Chronology of Films" posted at:
http://www.kodak.com/US/en/motion/about/chrono4.shtml

Posted by George Roher (Member # 91) on 01-27-2000, 10:12 PM:

The exhibitors wanted polyester? I was surprised to read that. I guess because it doesn't break, they assumed it would be another tool to help them run without projectionists.

Posted by Erich Loepke (Member # 166) on 01-28-2000, 03:27 AM:

John,

When I said "Eastmancolor", I was referring to the older stock that has the color fade problem. I'm sure that as soon as the fading was noticed, Kodak went to work on solving that problem.

It seems from reading the description of "short process", it was intended for films meant for quick release, such as TV programs. I guess that explains why SP is seen quite often on 16mm TV prints. Any thoughts on why SP prints tend to turn brown instead of red?

Thanks for the link--it was very informative.

Posted by Joe Redifer (Member # 3) on 01-28-2000, 05:20 AM:

George:

It's all salesmanship. I'm sure the poly-pushers explained to the exhibitors (and others) that polyester film would indeed be less likely to break. That's where they stopped talking about that feature. They didn't go on to say "Oh by the way, since it does not break, it can and will damage your equipment, causing you many costly repairs. And let's not forget the static cling that will take several years to finally come up with a reasonable solution. Still want to convert to polyester? Hello? Where did ya all go?"

I wasn't there, but I'm sure that is fairly accurate.

Posted by John Pytlak (Member # 331) on 01-28-2000, 09:40 AM:

Erich:

The newer more stable dye couplers invented by Kodak were not available for use in print film until the late 1970's.

The ECP-2B process was introduced in the early 1970's. Its higher developer temperature allowed shorter processing times. The lower temperature ECP process co-existed for over a decade, and was phased out completely after 1982.

Posted by John Pytlak (Member # 331) on 01-28-2000, 10:48 AM:

Joe:

Kodak certainly was NOT a "poly-pusher". In the report presented at ShoWest on March 8, 1994, I said:

"Comments reveal some problems with static buildup, payout control on some platters (may be related to static), slipping of rolls on platters, and loose winding of the film. These static and friction-related concerns need attention. There were also some adverse comments about the quality of the ultrasonic splices used by the laboratory, indicating some work may be needed."

"Many projectionists have serious concerns about the strength of polyester, and the potential for equipment damage...Many projectionists see the need for tension-sensing failsafes to cut the film and quickly shut down the equipment in case of brain-wrap or film jam. There is a real need for this type of equipment before widescale use of polyester film is accepted."

"Projectionists were displeased with the dust buildup, static, scratching, ultrasonic splice quality, looseness of the roll, slipping on the platter, and the risk of equipment damage".

"Film-cleaning technology needs to find greater use in theatres."

Kodak recognized and publicly reported the concerns with polyester release prints, and has spent hundreds of millions of dollars since 1994 to address these issues, leading to today's VISION Color Print Film. And further improvements are underway.

Posted by Dave Williams (Member # 299) on 01-28-2000, 01:21 PM:

I just have to chime in about an experience I had with this polyester film.

I have SPECO platters. Six months ago as I was doing a routine check on the projectors as they ran, I saw a brain wrap in progress and attempted to shut it down before it got worse.

Instead when the tension got so tight it broke one of the rods that the rollers are on before I could shut it down. The damn metal rod broke to save the film.

That isn't the real problem. It came off with such force that the rod flew into my face, puncturing my lip and breaking three of my teeth. Plastic surgury was required, and although you cant even tell anymore, trust me I can still feel it.

Try explaining to a crowd of 200 that thier show is off because the projector broke and attacked you (all while holding your face together with a drenched bloody rag).

This polyester film is deadly I tell you. Someone is going to get killed and I am sure it will be me.

------------------
"If it's not worth doing, I have allready been there and done it"

Posted by John Pytlak (Member # 331) on 01-28-2000, 02:16 PM:

Dave:

Ouch!!! Kodak has always recommended tension-sensing failsafes for all equipment handling polyester film. They should be installed on the feed side of the projector, where the most tension is likely to build in case of a film jam. Most of the platter manufacturers, Kelmar, Avask, and others supply them. In most cases, if tension builds, a moving roller trips a microswitch, and cuts off power to the projector. A good design allows some slack, so the projector can coast to a stop. At one time, Kelmar made a failsafe called the "Film Chopper", which literally cut the film cleanly with a spring-loaded shielded scissor blade when the device sensed excess tension. When the jam was cleared, the film could be respliced with minimal loss of continuity.

The needed tension-sensing failsafe is NOT provided by the usual film break / automation cue detector located at the projector payout.

Posted by Joe Redifer (Member # 3) on 01-28-2000, 04:22 PM:

Upon re-reading my post, I do not believe I gave any indication that Kodak was a "poly-pusher". That would make me look like a dumbass since Kodak's position was explained above mine anyway. But there were "poly-pushers" in the industry, obviously.

Posted by Joe Redifer (Member # 3) on 01-28-2000, 04:27 PM:

Also -- I have heard bad things about those "tension sensing" failsafes. The kind that hook onto the platter. I hear they have the reliability factor of 1 on a scale of 1 to 30, 30 being completely reliable. And how many exhibitors are going to invest the money into something like this, anyway? They wanted poly so they could (theoretically) save money, not so they could spend more!

Posted by Randy Stankey (Member # 64) on 01-28-2000, 05:32 PM:

Question:

What about those FM-35 failsafes?
They have a "motion" sensor as well as a "presence" sensor. If logic serves me right, doesn't the lack of film comming OUT OF THE BOTTOM of the projector mean that there's no film going IN THE TOP? Even so, the "motion" sensor in 'failure' means that there's something wrong, doesn't it? (unless it't a type-2 failure)

If all this is true, how do you hook up those FM-35's? My CFS automation doesn't recognize the "motion", only the "presence".

Posted by Richard Hamilton (Member # 321) on 01-28-2000, 11:47 PM:

If you no longer use exciter bulbs, then the motion should be hooked up to the exciter circuit of your automation. After you hit the start button, by the time the exciter circuit turns on, it will sense motion. The theory of this motion/wrap detector works SOMETIMES. If the film wraps and the platter shuts down because of the wrap detector, then the film should start paying out of the projector and onto the floor. Thus loosing it's tension, and motion not being seen. The only problem is that if the platter stops and the film still feeds through the failsafe just right.....the motion detector still sees it and doesn't shut down. The only solution to that problem is to wire the wrap detector directly to the automation. If you do that, then the projector shuts down any time the wrap detector is touched and the microswitch bumped.

Posted by Aaron Sisemore (Member # 145) on 01-29-2000, 02:28 AM:

Randy:

Yes the MOTION sensor on the FM35 will shut down the system if the film quits feeding out of the projector, however by the time this happens, the damage above the failsafe has already been done, at least the system will shutdown and you won't risk burning a lens or having the audience look at a burned frame for umpteen minutes until someone complains..., and unless you custom-wire, the only automation that will shut down the system via the FM35 motion sensor 'out-of-the-box' is the Component Engineering TA-10...

To add the MOTION sensor to a CFS automation, all you do is find the wires that go to the normally open contacts of the motion relay and connect them in series with the existing presence relay. Most if not all CFS automations have a seven second delay upon pressing the START button before the failsafe is engaged, so the film not moving will not prevent a start or trigger a false motion failure as the film runs up to speed. Hope this helps!

Aaron

Posted by Robb Johnston (Member # 239) on 01-29-2000, 10:03 PM:

It is true that the tension failsafes have a low rate of working properly on static wraps. The main reason for this is that until recently all of the theatres I have worked at have had the failsafe wired not to the projector failsafe, but to the power supply of the platter. (Strong alpha or DMC platters in all cases) The idea is that a gradual wrap will cause it to trip at 10 wraps on a 10-12 foot hrow between the tree and the projector. when the switch is engaged, the platter ceases to take-up, the carriage drops setting off the projector failsafe, and you don't even have to pull new wire through the wiring trough and into the projector automation.

With static wraps, the stoppage is often immediate, and the carriage doesn't have a chance to drop out, hence the projector keeps trying to force film through. I allowed one of my more inventive projectionists rewire the failsafe into the automation when he came up with the idea, and boom, no more cases of massive damage due to static.

Of course, now we use film guard and no longer have static problems.

Posted by John Walsh (Member # 168) on 01-30-2000, 03:38 PM:

A big rant on the polyster release print issue:

I realize I'm going against the grain here, but I feel that it was poor practises by the exhibitor that lead to polyester. I don't think there was any 'chicken or egg' thing here; Theaters got too damn cheap first (with inexperinced operators and poorly maintained equipment) and wrecked prints that are needed at other theaters. As a result, the distriubtors introduced polyster.

On this forum, and at the newsgroup r.a.m.t., there are many horror stories of trashed prints. Scott noted that (he had heard) all of the (1990) 70mm re-released prints of "Sound of Music" were destroyed. Gordon got a damaged print 70mm of, "LoA." If this is what happens to 70mm prints, imagine the carelessness with 35mm prints. No wonder no one releases 70mm anymore, even after the huge cost reduction DTS offers.

I'm sure that the people here (at this forum) do a good job in their part of the motion picture industry (operator, tech, manager, etc.) But I know we here do not represent the exhibition end as a whole. Most of the theaters I've seen are staffed by young, inexperinced transients with no interest in a theater career. They are not stupid people: Exhibitors have degraded the job positions to the point where it's only for high school kids and they are just working to get through school, extra money, etc.

So, prints get damaged. And who pays? Not the theaters. When was the last time you heard of a theater actually paying for a damaged reel(s)? Sure, you've heard of it happening, but only when the reel is totally destroyed. If you can make it to the end of the run, it's put in the can and out the door, hopefully before anyone mentions it. I don't feel it's fair to blame film exchanges for not inspecting; with a 3000 print release, how could they? Besides, if everyone took care of prints, they could just go from theater to theater.

It's amusing to learn that NATO approved polyster back in 1991. They sent a questionaire around about a year ago that sort of implied that, 'they were going to get to the bottom of this problem.' Guess they forgot they helped start it. I also don't remember any notices from them (in 1991) saying; 'Here comes polyster, and watch out.' Although, I'm sure it was printed somewhere, probably underneath the notice about the annual picnic.

Lastly, (if you've read this far!) any theaters equipment should have safety shutoff devices installed by now. A polyster-caused problem should only result in a shutdown and maybe re-adjusting those 'any angle' rollers. There are plenty of add-on safety devices (for pre-polyster) equipment, and other options (humidifers, Film-Guard, etc.). While I do feel that it was unfair how quickly polyster was forced on the theaters, we've known about it for a long time now. If a theater does not have safety devices installed, or bought cheap, ineffective devices, that theater is poorly run and probably has other problems as well. These will be the same people who won't convert to silverless soundtracks, and will act all surprised when there's no sound.

While there are several reasons why there is a decline in the quality of theaters, I feel the number one reason is the owners themselves. Poor projection and auditourium design, on screen ads, high candy stand prices, coupled with home TV theater systems, DVD, large displays, etc. (did you ever think you could have 5.1 or DTS at home!?) This gives the public both a reason NOT to go to the theater, AND a reason to stay home.

Anyway, sorry for the rant. It's sad to see a once great industry go down.

Posted by Christopher A Kerr (Member # 151) on 01-30-2000, 06:15 PM:

On the subject of failsafes, I have had fairly good luck so far (Knock on wood)

. I am not sure of the make and model, but they work by sensing any tension at the top of the feed side of the platter tree which will move a roller and trip a microswitch. They are wired to shut down the takeup platter. The platter slowly comes to a stop and the rewind plate drops. Once the plate hits the bottom, it shuts off the projector motor and the lamp. Any tension more than about 2 wraps of brainwrap will trip the sensor. I do occasionally get accidental show stoppages if the tension peaks for a short time, but any time I have actually had a serious brainwrap, The projector has shut down before any serious equipment damage of film burnout.

Cheers
Chris

Posted by Randy Stankey (Member # 64) on 01-31-2000, 03:35 PM:

I've looked into wiring up the motion sensor in series with the presence sensor. The green "Ready" light won't come on. The proj. will run correctly, otherwise.

Some of the people I work with couldn't comprehend this and would just be walking around with their thumbs up their ass! I tried making a modification to the automation once before and I had to undo it.

I thought that there could be a device with a logic gate in it, or something... It's ON when the presence is on until the motion comes on them it's off when either one drops out. In other words an OR gate until motion, then AND. It'd have an indicator on it that'd tell you which one dropped out.

As for the film STILL getting damaged, yes, I agree but it's better than nothing!

Posted by Christopher Seo (Member # 7) on 02-01-2000, 05:48 PM:

I think the one thing polyester has going for it is its chemical stability. I find it interesting that everyone here probably has some interest in film preservation, yet no one has addressed the decomposition of acetate stock. Of course, I doubt that mainstream exhibitors would really care whether a print survives beyond its short initial release, so this cannot be why they pushed polyester.

Posted by Scott Norwood (Member # 30) on 02-01-2000, 07:03 PM:

Christopher makes a good point about polyester--it doesn't (as far as we know) turn to dust like nitrate or turn vinegar like acetate.

Personally, I'm pretty indifferent to polyester, if not slightly partial to it. This is probably because I've never had to deal with platters and "brain wraps" and other horrors. The only exception would be the godawful Eastman B&W ESTAR-base stock that, nine times out of ten, sheds white dust all over the place, even when running 20-minute reels. This may be a lab problem, though...I've seen some ESTAR-base B&W prints that were fine (Casablanca and Maltese Falcon - 1998 reprints - come to mind, but there are others).

Posted by John Pytlak (Member # 331) on 02-02-2000, 02:34 PM:

Polyester base DOES offer many advantages. It is much less subject to chemical attack or deterioration (that's why you can't make cement splices). It also has minimal aging shrinkage, is dimensionally stable with changes in temperature and humidity, and does not require the use of solvents during manufacturing. It can be recycled (it is basically the same plastic that is used for carbonated beverage containers: PETE 1). It's durability and strength are real advantages in reducing tearing and perforation damage, but proper equipment design (e.g., tension-sensing failsafes) is needed to reduce risk in case of a film jam.

Since the 1950's, polyester has been the base of choice for dimensionally critical applications like graphic arts films. The IMAX projection system was designed to take full advantage of its characteristics, and many "special venue" theatres (e.g. Disney World, iWERKS ride films, etc.) prefer polyester for its durability. Many "special venue" prints on Kodak ESTAR base film have lasted tens of thousands of showings.

Compared to previous polyester print films, Kodak's new VISION Color Print Film uses a transparent process-surviving conductive layer to help control static, and a polymeric backing layer to optimize friction and wear characteristics.

Posted by John Pytlak (Member # 331) on 02-02-2000, 03:02 PM:

Scott:

The B&W prints that had emulsion-side "flaking" were probably not properly lubricated. Kodak has recommended edge-waxing of 35mm prints since 1922! Kodak's processing recommendations (H-24.02) and SMPTE Recommended Practice RP151 specify edge-waxing for optimum print performance. For the same reason you would wax a floor or fine automobile, edge-waxing reduces abrasion of the film surface by the film-contacting components of the projector.

For more information, read: "Lubrication of 35-mm Release Prints for Extended Projection Life" by Edward Mino and Rodney Perry, published in the October 1983 SMPTE Journal.

Posted by William Hooper (Member # 71) on 02-03-2000, 03:00 AM:

quote:
The IMAX projection system was designed to take full advantage of its characteristics, and many "special venue" theatres (e.g. Disney World, iWERKS ride films, etc.) prefer polyester for its durability.

What has been the experience of the IMAX & other special venues regarding static, compared to mainstream exhibition?

Did they have horrible static teething periods, or, since designed for polyester, did they just do it all by the book (i.e., environmental control, etc.) & have few problems?

Posted by Christopher Seo (Member # 7) on 02-03-2000, 03:59 AM:

I saw a nearly-brand-new IMAX setup, and their film delivery system, a 5-deck platter, is analogous to conventional platters, except on steroids. I recall the projectionist saying that IMAX prints have been thrown in the past, perhaps due to problems with the older system (although I think their new system was put in just to upgrade to 3D capability), but I'm not sure if any have wrapped.

Posted by John Pytlak (Member # 331) on 02-03-2000, 08:00 AM:

AFAIK, "Static Cling" has not been an issue with IMAX theatres. They have specifications regarding temperature and humidity control, and all have "on-line" film cleaners, usually either PTRs or buffer brushes.

In addition to Gordon McLeod, I'm sure there are some other IMAX projectionists who either participate or "lurk" in Film-Tech Forum. What are your experiences regarding static?

"Fantasia 2000" was the first major IMAX feature printed on the Kodak VISION Color Print Film having the conductive anti-static layer.

Posted by Gordon McLeod (Member # 33) on 02-03-2000, 09:49 AM:

Until very recently all Imax/Iwerks theatres running 15perf 70 used reel to reel (sorry Brad) even though when one looks at booth pictures they are reels lying on there side with on side expossed. In fact they are usually reffered to as platters but they rewind just like reels So the only major static issue was dirt clinging to the field flatner lens. All the new IMAX theatres use a modified Kinotone platter and I have heard of one or two instances of problems but the cause was not mentioned.

The 8 peerf 70 industry has used christie and xetron platters for some time but are all equipped with antistat devices

In the case of 15perf rolling loop operation the use of polyester was mandated from day one mainly because of its dimensional stabability

Posted by John Walsh (Member # 168) on 02-05-2000, 10:51 AM:

I was looking for any SMPTE articles about Sensurround (didn't find any,) but I did find a survey done by Agfa in 1979 regarding the use of polyster film for regular 35mm projection. Some interesting statements:

1.) "... An additional concern is the greater mechanical strength of polyester film, which could make it more likely to damage equipment: this particular concern was suspected to have a psychological basis in that in many cases there were only unfounded rumours of damage."

2.) [About half of the labs surveyed said that;] "... the use of polyster base film will only grow [in the future] because their customers are pushing them to use it."

"Representing the opinion of the majority, who expect the use of polyster to grow [the lab execuitives surveyed said:] "I see more of it being used. Labs have an aversion to polyster, but the customer wants us to use it even if you tell them triacetate is better..." [another] "... I can see people asking for a longer lasting film, and we would be forced to service them..." [another] "...Eventually, it will be all polyster because of longer life and quality."

See SMPTE Journal: Feb. 1980 (v.89) pp. 106:
"The Use of Polyster Film Base in the Motion Picture Industry- a Market Survey"