Film-Tech Forum ARCHIVE: IB going vinegar... Best to store wound tight or loose?

This is topic IB going vinegar... Best to store wound tight or loose? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Mark J. Marshall (Member # 1409) on 01-29-2005, 01:16 PM:

IB Tech film. Starting to turn. It gets pulled out and rewound back and forth a few times once every few months to air it out. It's stored with molecular sieves in vented plastic cans from Kodak. Is it best (from the vinegaring process' standpoint) to wind it tight or loose?

Thanks.

Posted by Leo Enticknap (Member # 534) on 01-29-2005, 01:48 PM:

AFAIK this doesn't make a significant difference to the deacetylation. Too tight and you risk pressing dirt and contaminants into the film underneath; too loose and you risk the film pack shifting and causing abrasion whenever it's moved.

Given that the container is vented and you're using molecular sieves (which to a certain extent will take care of humidity issues), keeping the film as cool as possible is the vital thing from here on in. It also wants to be wound base out.

Posted by Dan Lyons (Member # 1454) on 01-29-2005, 01:51 PM:

The sieves are meant to be used in a closed and sealed container.
2 options: open air on cores, or in sealed in cans with sieves and kept in the fridge [Smile]

Posted by Leo Enticknap (Member # 534) on 01-29-2005, 02:32 PM:

Agreed that sieves and vented cans are overkill, but I can't see that they'd do any harm. In fact, given the high humidity in a domestic fridge, the combination of all three (sieves, vented cans and stored in a fridge) may well be a way of getting the best of both worlds (low temperature and humidity plus evacuation of acetic gases) without spending serious money on state of the art air handling plant.

Posted by Mark J. Marshall (Member # 1409) on 01-29-2005, 03:33 PM:

I figured it might be overkill, but also figured it wouldn't hurt, and no amount of prevention is too great since there's no going back.

Guess I might have to get a bigger fridge! [Wink]

Thanks, gents.

Posted by Dan Lyons (Member # 1454) on 01-29-2005, 06:11 PM:

quote: Leo Enticknap
In fact, given the high humidity in a domestic fridge, the combination of all three (sieves, vented cans and stored in a fridge

Can't do that. Sieves need to be in an airtight container to work; exposing them to excess air, like in a vented can, would exhaust them quickly and turn them useless. Also look into getting the recommended plastic bags and moisture proof tape from FPC.
The instruction guide that comes with the can of sieves should have all this info on it; if you've lost it, full instructions are on the Kodak site here

Posted by Chris Trainor (Member # 9) on 01-29-2005, 06:13 PM:

Sieves in a vented can are useless. They do nothing for the film. They suck the moisture out of the ambient air, if you put them in open air (vented can) they'll just suck from the air in the room that the can is stored in.

The whole reason they work is because they absorb water and acid from the air in the container they are in.. if you use a vented can your container is the whole room.

--Chris

Posted by Mark J. Marshall (Member # 1409) on 01-29-2005, 08:09 PM:

I have the bags and the tape actually. I was using them, but the odor was pretty strong when I took the film out of the bag, so I decided to let it air out for a while.

By the way, is that normal? I guess I probably expected the seives to absorb the gas that smells and thus reduce some of the smell, but maybe that was an unrealistic expectation. Or maybe the seives also give off a bit of a smell.

Posted by Leo Enticknap (Member # 534) on 01-30-2005, 05:05 AM:

quote: Mark J. Marshall
I have the bags and the tape actually. I was using them, but the odor was pretty strong when I took the film out of the bag, so I decided to let it air out for a while.

If the element(s) have passed the autocatalytic point or are on the verge of doing so (have you tested them with a/d strips?), plus the atmosphere inside the bag was pretty humid when it was sealed, I can believe that.

quote: Chris Trainor
Sieves in a vented can are useless. They do nothing for the film. They suck the moisture out of the ambient air, if you put them in open air (vented can) they'll just suck from the air in the room that the can is stored in.

Inside a fridge is not in the open air. If it isn't opened too often, it's probably a 99% airtight environment. I'm not sure how efficient the door seals or the gaskets where the coolant pipes enter and exit the main storage compartment are. In fact, assuming the fridge is reasonably full, they might (I say might because I've never tried this myself) do a reasonably good job in creating a low temperature, low humidity environmnent in which to store small quantities of film in a situation where either the justification and/or the money isn't there for building a full-scale environmentally controlled vault.

Because of the condensing action of the coolant generating more moisture all the time, you'd need to replace the sieves quite regularly, I'd guess.

Posted by John Pytlak (Member # 331) on 01-30-2005, 09:44 PM:

Yes, Molecular Sieves should be used in a sealed, unvented container. If exposed to open air or used in a vented can, they will quickly load up with moisture adsorbed from the air.

You can put a fresh Molecular Sieve on a sensitive lab scale and actually watch them gain weight as they adsorb moisture from the open air. They can hold up to an additional 22 percent of their weight in material (acetic acid vapor, organic vapors, moisture) they adsorb. Then they need to be replaced.