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Topic: filmguard and failsafes

Manny Knowles
"What are these things and WHY are they BLUE???"

Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002

posted 01-04-2004 10:19 PM

quote:
I gues my big beaf with the FM35 failsafes is that if it is film it better damn well detect it being there not be well maybe on sunday with a full moon we like this particular stock

Say what?

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 01-04-2004 10:25 PM

exactly what it says
I get so many calls of false shutdowns because ti didn't like B&W or Mag or something else
The Eprad Strong one has bever given any grief

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Aaron Sisemore
Flaming Ribs beat Reeses Peanut Butter Cups any day!

Posts: 3061
From: Rockwall TX USA
Registered: Sep 1999

posted 01-04-2004 10:44 PM

Gord, I used to have the exact same problems with FM35s (Especially the ones that (I swear!) ONLY would go bezerk on Steven Speilberg movies) [Eek!]

until the upgrade kits were installed and then I have NEVER had another problem with Speilberg titles, IB receiver, or B/W Stocks.

-Aaron

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 01-05-2004 11:54 AM

I've had problems with FM-35s regardless of vintage and upgrades...customers have now had me switching them out for something else. The Kelmar prox cue detectors with the mechanical drop arms seem to be the most reliable in picking up cues and not false triggering. Then again, they made it super easy to be careless and miss the first roller and drag the entire print over the faisafe bat (scratching the bejesus out of it).

Steve

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Don Olson
Film Handler

Posts: 20
From: Seattle WA
Registered: Jul 99

posted 01-05-2004 02:15 PM

The FM-35 is an optical sensor. It relies on the projectionist for an occasional cleaning and that the film be able to reflect light. 99.9% of the time both sensors will read properly. There are however rare pieces of film that won't reflect enough light to make one of the sensors work. But...I have yet to see film that will fail both of the sensors.

If you are using the FM-35 with a TA-10 automation you can bypass the function that is failing on a particular print and rely on the other. The TA-10 has bypass switches installed. If you are using it with another brand of automation it is a simple task to parallel the motion and/or presence outputs with a bypass switch.

The motion sensor will work on film that is almost invisible to the presence sensor. This is a function of how they detect. Motion looks for slight changes in the amount of reflected light as it either passes through the sprocket hole or is reflected off the film between the holes. Presence is looking for a minimum level of reflected light. We set this level after "real world" tests with all types and conditions of film stock. The testing included waxes, lubricants, and also film stripped of both. The usual culprits for a presence failure are…very worn, scratched leaders and odd mylars used for interlock leaders that have a very opaque side facing the sensor.

The next FM-35 that leaves home will be named 13774. That says it all.

The only advantage I can see to a drop arm failsafe is that you can used it covered with projector oil and film dust. So, for this kind of use it is ideal.

Don Olson
Component Engineering

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Carl Martin
Phenomenal Film Handler

Posts: 1424
From: Oakland, CA, USA
Registered: Feb 2002

posted 01-06-2004 08:52 AM

i've been running the old leaders and the results so far are inconclusive. actually, they are a mixed batch. some have color stock black leader, some b&w. some emulsion in. naturally i'm not 100% sure which ones came off the prints that were misbehaving [Mad]

.

the techs weren't ever able to get the motion detector to trip while they were testing it, but they weren't using these leaders.

one of the leaders i've been running would shut down consistently... when taking up on the bottom platter (?)... 2 nights ago, but not yesterday (??). the only differences were end-of-day vs. start-of-day and top feed vs. middle feed, but the feed platter is so far isolated from the problem i'd rather blame little fairies.

it's one of the leaders with b&w, emulsion in. however, the shutdown happens a foot or so before the b&w hits the failsafe. there are some sprocket indentations between the perfs here, but it's a long stretch of these (~6' maybe) that has mostly gone through already by the time it decides to shut down. before that there is some scrunching of the leader, which has just reached the bottom platter roller when the shutdown occurs.

we'll see how the equipment cooperates tomorrow. i need to try some more things to figure this out.

what exactly does the motion detector want to see? does it see light bouncing from the film alternating with no light as the perfs pass, or vice versa?

brad, i'll send those black samples tomorrow. i didn't want to cut up any leaders so i took some unused stock.

carl

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Brad Miller
Administrator

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

posted 01-06-2004 03:18 PM

You may have touched on another issue. You do know that if the platters aren't timed quite fast enough that there is a magic spot where when the motors are warm they will takeup fine (as in during testing), but when the motors are cold (such as first show in the morning or bottom platter in general which sees little use) that it could literally be nothing more than your takeup platter running out of speed.

Put something in the brain to hold the payout arm at full throttle and put a piece of tape on the edge of the platter. Now tell me how many revolutions per minute it does over the course of exactly 60 seconds.

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Carl Martin
Phenomenal Film Handler

Posts: 1424
From: Oakland, CA, USA
Registered: Feb 2002

posted 01-07-2004 07:31 AM

all 3 decks did about 28 rpm at full throttle at the start of the day. i let the bottom deck spin for 20-30 min then timed it again, and it did maybe 1/3 revolution more.

i ran the suspect leader a bunch more times and... nothing. no shutdowns.

carl

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Manny Knowles
"What are these things and WHY are they BLUE???"

Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002

posted 01-07-2004 08:20 PM

quote:
it's one of the leaders with b&w, emulsion in. however, the shutdown happens a foot or so before the b&w hits the failsafe. there are some sprocket indentations between the perfs here, but it's a long stretch of these (~6' maybe) that has mostly gone through already by the time it decides to shut down. before that there is some scrunching of the leader, which has just reached the bottom platter roller when the shutdown occurs.

Why not retire that fishy leader and use a different one in its place? See what happens.

Your failsafe doesn't care which platter deck you're using. If they're all timed exactly the same then it should either work or fail consistently depending on whether or not they're timed correctly.

BTW have you tried swapping the failsafe to see if the problem follows it (or stays with the original system)? That would tell you a whole lot right there!

quote:
i'd rather blame little fairies.

Oy!

Y'know...They really resent being called that. [Roll Eyes]

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Carl Martin
Phenomenal Film Handler

Posts: 1424
From: Oakland, CA, USA
Registered: Feb 2002

posted 01-08-2004 04:21 AM

i meant no disrespect to fairies!

that leader has been retired, but i was running it just to troubleshoot. to figure out why it (and others) was causing shutdowns, it is necessary for the shutdown to happen.

i can't switch failsafes as we only have one fm-37 and 2 fm-35's. i'm thinking the '37 is just plain more sensitive than the '35's.

everything's working fine now with new leaders and all, but i was hoping to confirm my view that using filmguard had nothing to do with the problem. we've been told not to use it now, at least for the time being.

well, i'm not a tech, and it's my ass if i mess anything up, so i think i'm going to let it be for now and hope this blows over.

carl

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Manny Knowles
"What are these things and WHY are they BLUE???"

Posts: 4247
From: Bloomington, IN, USA
Registered: Feb 2002

posted 01-08-2004 11:34 AM

Be sure and let us know what happens if/when you start using FilmGuard again.

Only, next time, you may want to retire the leaders when they start getting ratty.

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Brad Miller
Administrator

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

posted 01-14-2004 05:06 AM

I received clips of Carl's leader samples.

#1 A-50 NT-Audio/Visual "blue" frameline countdown leader.

#2 Generic B-100 black frameline leader (this is the newer type which appears to be on black and white stock with slightly grey framelines and edges)

#3 Generic B-100 black frameline leader (I am almost positive this is NT-Audio/Visual leader, but like I said "almost", not for certain. This stuff has been around since forever and is printed on color stock with light yellow colored framelines.)

For what it's worth...

I have never seen an issue with #1 on CE failsafes.
I have not used #2 with CE failsafes, but looking at the leader I cannot see where it would be an issue.
I have used #3 with CE failsafes before and had issues. Not very frequently, but occasionally it would stop "seeing" the leader.

So Carl, how do you like that indestructable opaque leader I sent? [Big Grin]

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Carl Martin
Phenomenal Film Handler

Posts: 1424
From: Oakland, CA, USA
Registered: Feb 2002

posted 01-15-2004 03:12 AM

brad, thanks for sending that. i was going to let you know i received it. i also dug up some fullcoat that i got on ebay a while back, different color. soon i'll be making up some more leaders, and i'll try it out.

interesting that the color stock b-100 is the less reliable. in any case, i spent several days running all the old leaders, but i couldn't get any of them to shut down after the first day. so it's all a mystery to me.

don olson did tip me off that the fm-35 has an ic on the board with the failsafe sensors which helps to square the signal picked up by the motion sensors. the fm-37 doesn't have this. so what works on the fm-35 might not work on the fm-37.

one thing i'm still wondering is if it's ever a problem for _too_ much light to bounce back between the perfs.

carl

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