Film-Tech Forum ARCHIVE: Filmus-Interuptus!

This is topic Filmus-Interuptus! in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=000840

Posted by Ian Price (Member # 14) on 04-08-2000, 04:45 PM:

Here was a baffling problem. Our new film, Mifune, was playing and it would stop at the beginning of the fourth scene, every time! Our lamp house has a few problems, one of which is, you can’t strike a hot lamp. You have to wait 5 minutes for it to cool down. So I would give the patrons passes and wait to start the film. On the last show last night I got a clue and left the lamp on. This morning I ran the film twice to that spot and there was no problem. Then I ran the film for an audience and it stopped! I had wanted it to stop so that I could identify the problem. So I gave out passes and went up and looked at the film for the third time. There was no damage, cues or other problems.

I have optical fail-safes and I thought that they might be the problem. While the film was stopped, one of our spastic ushers asked why the film was curled? It was cupped in and when it ran through the fail-safe it would curl away from the optical sensors. On the fail-safe was a pot labeled, “Bobble Delay.” I have no idea what Bobble is but I figured delay would be good. The pot is marked 0-4 and it was set at 0, I dialed up to four and took the film out. Four seconds later the fault light came on.

It’s now Show Time and we are going to see if this solved it. I can’t believe that curled film would cause me such problems. I don’t think I would have had this problem with a split, mechanical fail-safe.

Posted by Brad Miller (Member # 2) on 04-08-2000, 05:41 PM:

and the brand and model of the failsafes are???

Posted by Ian Price (Member # 14) on 04-08-2000, 05:48 PM:

Strong FP-350 Optical Failsafe and Proximity Cue Detector.

Posted by Gordon McLeod (Member # 33) on 04-08-2000, 06:57 PM:

The bobble delay sets the amount of time that the film can be slack under the sensor mainly to accomodate sloppy takeups at start up
Set it at max and the cupping of the print will get ignored

Posted by Ken Layton (Member # 133) on 04-08-2000, 07:13 PM:

The Strong FP-350 is not the greatest failsafe. It would be better to use the Component Engineering FM-35 cue detector/failsafe---it's much more reliable.

Posted by Ian Price (Member # 14) on 04-08-2000, 08:00 PM:

Fine, buy me five FM-35s, Ken.

I play the hand that I was dealt. I can live with these. I just find it strange that we went 12 weeks before we discovered this problem.

Mifune is one of two Triacetate films we are showing this week.

Posted by John Pytlak (Member # 331) on 04-08-2000, 08:38 PM:

Just as with polyester, abnormally high or low relative humidity can cause enough curl to be an issue with triacetate. Do what you can to keep the RH between 50 and 60 percent.
An old triacetate print may also suffer some shrinkage or warpage if stored improperly. One of the real advantages of polyester over triacetate is it's dimensional and chemical stability.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment 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 Ian Price (Member # 14) on 04-08-2000, 08:56 PM:

I don't believe in Humidity. But what do I know, you guys make the stuff. Santa Rosa has had 64% humidity for the past few days. That is in the ballpark, right? I know it changes with airconditioning, but ours isn't that good.

I suspect that it is an old print that was wound on the shipping reels improperly. This film has been around the block several times. I have print #5A.

Posted by John Pytlak (Member # 331) on 04-08-2000, 09:42 PM:

Ian:

It might be 64% RH outside, but the humidity in the projection room is what counts. Get a Radio Shack or Edmund Scientific digital humidity gauge, and then you'll know what it really is. Ocean breezes or desert Santa Anas can really cause wild fluctuations in California. Winter heating makes it really dry in cold climates. Having lamps rated in kilowatts and all that air being sucked out of the projection room to cool the lamps makes precise humidity control difficult, but do the best you can with HVAC adjustment, and humidifiers or dehumidifiers, as the case may be. Fifty to Sixty is Nifty.

But I agree with you, the likely cause is old triacetate film that may have been wound incorrectly, or has shrunken or warped a bit due to improper storage.

Posted by John Walsh (Member # 168) on 04-08-2000, 11:05 PM:

We use Xetron failsafe detectors- the regular microswitch kind. We actually had the optical failsafes, and they were such a pain we removed them.

Once we were running the same trailer in three of our houses, (I think it was "ID4") and all three projectors would 'failsafe' at the same location in that trailer. I could not see anything wrong with the film; it looked smooth and flat. After running out of ideas, I e-mailed John P., and he kindly looked up records for that film to see if there was a different kind of emulsion used, or something, but didn't find anything different about it.

Now, don't quote me or anything, but my understanding is that so many people complained about those Xetron optical failsafes that they agreed to replace them with the microswitch type. But, you had to specifically ask for it, as they were not too keen on changing every one, sepecally if it was working OK.

Posted by Bryan Redemske (Member # 354) on 04-11-2000, 12:43 PM:

We had a Component Engineering failsafe, pretty new...it kind of let a film go for a bit while not noticing that the takeup platter wasn't moving. Basically, the film stuck inbetween the rollers so the tension stayed there. there was a bit of film on the floor after that one, needless to say.

Posted by Alan Brandt (Member # 426) on 04-11-2000, 03:29 PM:

Darn-tootin not to strike a hot bulb, dumb things liable to crack and explode depending on how hard you decided to reef it. And 5 minutes cool-down time is about what my managers expect when it comes to removing xenon and replacing bulbs. Gosh forbid waiting until the END of the night!

Posted by Nicholas McRobert (Member # 205) on 04-11-2000, 05:53 PM:

In my experience of Component Engineering failsafes, I had the same batch of 4 or 5 trailers (Schindler's List comes to mind) play havoc and shut down in the same place. I also had severe problems when I tried running any feature printed on Black and white stock. Always ended up running manually without the automation. Something to do with the silver in the stock and its being different to colour stock, perhaps?

Posted by Aaron Sisemore (Member # 145) on 04-11-2000, 10:19 PM:

Nicholas Said:
"In my experience of Component Engineering failsafes, I had the same batch of 4 or 5 trailers (Schindler's List comes to mind) play havoc and shut down in the same place. I also had severe problems when I tried running any feature printed on Black and white stock. Always ended up running manually without the automation. Something to do with the silver in the stock and its being different to colour stock, perhaps?"

It was due to the original CE failsafe sensor design not reflecting the IR beam back to the detectors when running B/W film (and IB Tech receiver stock, and certain color film as well. Component Engineering has a very inexpensive retrofit kit (the sensor with the red dot and extra IC chip on it) that makes these failsafes almost bulletproof as far as detecting any type of film goes. Never had any stoppages related to failsafe/film stock combinations since. I am sure Bill Purdy will have more to say on this subject.

Aaron