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Arri IIC and B&W 35mm film (why the problems?)


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#1 PKM

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Posted 18 May 2005 - 02:09 PM

Hey guys.

I originally began a thread on the issue of having problems with running Black and White 35mm film through my Arri IIC (it's, I believe, an Arri IIC/B)

http://www.cinematog...?showtopic=6689

In a nutshell, there seemed to be a problem where B&W film, which we had obtained through a short ends distributor, didn't run through the camera. The film would intermittently be torn between perfs, and the film would lose its loop in the camera. The roll we were running through was a 400 foot short end, incidentally. a short colour 35mm roll (about 200 feet long) ran through the camera no problem.

When we physically lined up the B & W short end with a length of colour film, there seemed to be a bit of perforation drift, by the equivalent of a full perforation over the course of a 6 foot strip of film. It seems, from the answers I received, that this shouldn't be the case. In any case, we wondered if that had something to do with the film not running properly.

UPDATE:

We bought a 400 foot new roll of B & W film, directly from Kodak. This film clearly does match up, perforation-wise, with our colour 35mm film. But, when we run through either the full B&W roll, or a shorter one (100-200 foot roll), the same thing happens. Perfs get torn, the film loses its loop. Yet when we go back to the colour 35mm stuff (which lines up exactly, same perfs, everything, same amount of feed footage in the mag) it runs fine. Arrghh... what gives?

Peter
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#2 David Mullen ASC

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Posted 18 May 2005 - 02:52 PM

B&W film is thinner but I can't imagine a warhorse like the Arri-2C having a problem with that, but clearly yours is...

I'm sure the problem is not the film, but with your camera dealing with the b&w emulsion -- I'd take it to a camera repair tech.

This is b&w camera negative stock, right? Not some sort of lab stock like hi-con?
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#3 Max Jacoby

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Posted 18 May 2005 - 02:54 PM

What black and white stock are you using? It's not Orwo, is it? Because that one is a real pain...
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#4 PKM

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Posted 18 May 2005 - 03:22 PM

B&W film is thinner but I can't imagine a warhorse like the Arri-2C having a problem with that, but clearly yours is...

I'm sure the problem is not the film, but with your camera dealing with the b&w emulsion -- I'd take it to a camera repair tech.

This is b&w camera negative stock, right? Not some sort of lab stock like hi-con?

<{POST_SNAPBACK}>


Hey David,

Yes, it is regular camera negative stock from Kodak. We were initially wondering if the problem related to the short end stock being mislabelled. But the same thing is clearly happening with new 5222 Kodak stock.

Peter
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#5 Sam Wells

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Posted 19 May 2005 - 10:01 AM

I'm sitting here speculating but I think pointlessly (stuff like well I've had B&W get sticky in very humid situations; or maybe there is a pressure plate issue where there's not quite enough on the thinner B&W stock - but really if the stroke is set right I can't imagine loosing the loop for that reason).

I mean you can sacrifice what 5222 neg you have left (or get some more recanned) and run it through with the door open and the mag cover off.... see when you loose the loop...

(I don't want to insult you but are you **sure** your preset loop is correct ?)
(why color neg wd be more tolerant even then I dunno)

But likely this camera needs a trip to the service shop, you can't go around trashing fresh 400' rolls of film just wondering. I suspect you may just be "barely getting away with it" when shooting the color neg.... you're not doing the claw any favor subjecting it to this...

I wish I had something more profound to say...

-Sam
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#6 Simon Wyss

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Posted 29 September 2008 - 09:23 AM

Wish I could have seen the stock.

Now, your Arriflex has a claw tip and magazine sprocket roller to fit the holes of Bell & Howell perforated film (ISO, type N). I have the impression that there is something with hole size, I mean perhaps Kodak Standard perforation (ISO, Type P). If your stock is P perforated it may slip on the magazine's feed roller. Naturally then one of the loops will disappear and the claw begin to hack. You don't see the trouble because it starts in the mag. Try once and pull on the film leaving/entering the mag. Will it slide over the sprockets ?

It's Eastman 5222. It's possible that they made a mistake in the perforation station or you simply overlooked the different perf type. It must be stated on the can label. One hole pitch more over 6 ft equals 2.6 permille shrinkage. This is certainly not the the problem.
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#7 Christian Appelt

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Posted 01 October 2008 - 03:34 PM

Since the camera body has just the transport claw and the actual transport action is done by the mag sprockets, I'd look for the mag.

Peter, have you tried another mag with your b&w stock, and if so, does the same problem arise?
I suspect that something in the mag is not adjusted correctly, just so much that thinner b&w stock can "slip through" while slightly thicker color neg will not.

Max, we discussed the problem of Orwo stocks in another thread, but IIRC you had these problems with a fairly new Arri, was it a 235 or 435? I did a lot of IIB and IIC shooting with both old Orwo and new Filmotec/Orwo stocks and nothing like the lost loop problem described here ever came up.

The IIC's movement is so simple that it will pull through almost anything the mag sprockets will transport. Years ago I ran shrunken 20 year old Ilford b&w stock through my Arri, and even a few cans of Svema neg that was really badly perforated. Never lost the loop or had a jammed mag.

Simon, if you look at the mag sprockets, you can see they do not fill the perf holes, so they will work with a larger hole as well. KS perfs are not a problem with the IIC because it has no register pin, just the transport claw. I have shot titles to replace damaged titles from a silent film by using b&w positive stock which has KS perfs, and they came out steady (well, as steady as a IIC can be).

Edited by Christian Appelt, 01 October 2008 - 03:38 PM.

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#8 Rolfe Klement

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Posted 01 October 2008 - 03:46 PM

run some 5222 filmstock through the 2C with the viewfinder door open and point a video camera at it - records what happens - load into fcp and slow down video footage - this will tell you if the damage is happening at the claw. the plate or the mag entry or exit points.

Nice and cheap way of checking - if that doesn't work go see someone at Otto Nemenez (if you are in LA)

thanks
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#9 Dan Goulder

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Posted 01 October 2008 - 05:09 PM

My guess is that the pressure plate needs to be recalibrated. However, my speculation is just as useless as everyone else's. You're not going to get the camera repaired online. Do the obvious, and give it to a qualified technician to spec it out.
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#10 Simon Wyss

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Posted 02 October 2008 - 06:07 AM

All the better. I was not assuming such heavy mechanical errors with the magazine(s). Something seems to be really bad with it.
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#11 K Borowski

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Posted 02 October 2008 - 09:55 AM

Guys, I think this problem was solved somewhen in 2005. . .

Simon, quit digging up the past! ;-)

BTW, when you say 2.6 per mille, do you mean 2.6/1000" tolerance, 2.6 perforations per mile, or what?

Customary units are inherently confusing, without your trying to make them so :P
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#12 Simon Wyss

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Posted 03 October 2008 - 04:43 AM

Guys, I think this problem was solved somewhen in 2005. . .

Simon, quit digging up the past! ;-)

BTW, when you say 2.6 per mille, do you mean 2.6/1000" tolerance, 2.6 perforations per mile, or what?

Customary units are inherently confusing, without your trying to make them so :P

Gee ! Per mill. The thousandth part of something. In stead of one-tenth of a percent.

I shall let it rest in peace. Promised
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