ARRI-SR II Mag Failure??

[Sam Goetz]

I ran into a huge production problem this weekend, and while the rental people are trying to figure out what happened, I thought I might post here and see if anyone has ever had such a similar problem:

 

BASICALLY, 2 weeks ago I started shooting on this 16mm short with an Arri SR II. Our stock was ORWO UN54 100D Black and White Negative. It's an uncommon German film stock, but it is definitely legitimate. Personally, I like the look better than any other black and white on the market.

 

Anyway, we shot for about 6 days (16 rolls) with almost no problems, but on the 6th day one of our mags started making an insane noise and when our ac opened it up in the changing bag the film spaghettied out like crazy. We hand rolled it and put it aside. The next day, after doing some high-speed stuff the same mag started to have problems again. It lost it's loop, it started to tear perfs and again it made a horrible loud noise. We switched it out for a new mag. The next day we started using our new mag and were doing some highspeed stuff again and both of our back-up mags died in exactly the same way: loud noise, lost loop, and torn perfs. It was saturday and no rental house was open and we were in Pennsylvania, we had to end the shoot 2 days early.

 

Since then, we have been trying to figure out what happened. Some people have told me that some Arri-SRs are callibrated for Kodak Color Negative and need to be re-calibrated for thin black and white stocks. Orwo is definitely a thin stock, but I didn't think that such a small problem could destroy 3 mags, especially since Orwo is supposed to have a callibrated short pitch. I've also heard that it could be a worn-out pull-down claw.

 

Has anyone had any similar problems trying to shoot a lot of black and white 16mm negative Ilford or Orwo or Fuji because of thinness or uncallibrated cameras? Any advice would help because I'm worried that the rental house is going to blame Orwo and that Orwo is going to blame the camera.

 

Thanks,

Sam

[Rik Andino]

Were you using High Speed Mags?

 

Sometime Arri SR's standard mags don't work in High Speed situations.

 

Personally I've never heard anything

About a camera being calibrated for certain films...

 

I've heard that Ilford stock sucks because it's sprokets break

And that's probably because it's thinner than the standard Kodak or Fuji stock

And on Hi-speed situations it might be the cause that the stock is too thin

 

Anyways I'm sure the rental house we'll have some explanation

If they're a reputable rental place they'll tell you the truth

If they're not they might try to put the blame on something other than themselves

If they're responsible for the problem...

[Sam Goetz]

I've also heard from others that Ilford's thinness caused a lot of problems back in the day. But we weren't going any faster than 38 fps and as far as I believe the mags we were using were supposed to be able to handle that speed under any condition.

 

It would make sense that the thinness of the film would cause problems at high-speed, but when our camera started to choke we re-loaded and ran at normal speed and it still didn't work. Something happened to the mechanisms within the camera that stopped it from being able to run our film.

 

Any ideas?

 

Sam

[Don Davis]

If the film was coming loose from the collapsable core on the feed side, the film would bunch up in the feed side until no more film could fit inside. The claw would continue to pull down the frames, but with the film frozen, you might get some torn perfs. It usually takes a little while in this situation for the feed side to fill up. And ultimately it does make a lot of noise.

 

If this is indeed happening on multimple magazines, it sounds to me like either the loader forgot to clamp shut that collapsable core, or the clamp came loose, something that is more likely to happen during high fps shooting. So much of the SR cameras are in the mags, that if there's a problem in mulyiple mags, I'm inclined to look at human error. Hope this helps.

 

Don Davis

2nd AC/novice DP

Los Angeles, CA