Time to order your acetic acid

[John Cook]

I once knew a cruise ship photographer in the days when those pictures were done in B&W. His lab was deep in the bowels of the ship against the hull below the waterline. He used to complain that in winter the cold ocean water would cool his lab sufficiently to freeze his acetic acid.

I see that the label on Ilfostop calls for storage above 40 degrees F. And my chemistry notes state that pure acetic acid freezes at 16.7C or 62.06 degrees F.

In this neck of the woods (according to their tracking website) UPS trucks are loaded before 3:00 AM, but don’t deliver here until around 6:00 PM. That’s fifteen hours bouncing around in an unheated truck.

Since there are no more stocking dealers nearby, I just laid in (mailorder) several months of stop bath before winter sets in. Just thought the rest of you Northerners might like to do the same.

[Tom Westbrook]

I usually buy stop bath locally so temp is not an issue, but I do make a point of ordering my winter's supply of Polaroid Type 55 before it gets to be below freezing. I wonder what the frezing point of Polaroid's developer goop is? I don't know if acetic acid is damaged by freezing, but I sure know Type 55 usually is.

[Jim Galli]

Oh great. Now you tell me. I've got Polaroid 55 dating from 1991 in the freezer keeping "fresh!"

[Michael S. Briggs]

Your friend would have a problem with acetic acid freezing in his darkroom because he couldn't use it in solid form. I'm not sure that this is a problem for shipping -- I would think the acetic acid would be unharmed by freeze/melt cycles and so could be used when it warmed up in your house. Presumedly the plastic containers used today wouldn't have any difficulty with slight volume changes from the solid/liquid transition. Perhaps someone more knowledgable about chemistry than me can explain why Ilfostop needs should be stored above 40 degrees F. Nearly pure acetic acid has the name "glacial" from its property of freezing in a cold room. Mixed with water the freezing point is reduced. Another approach would be to buy the other concentration that is common in photography, 28%, but I don't know what the freezing point is. This would have worked for your ship-board friend.

Jim, Polaroid says that their instant films should not be frozen. Refrigeration is fine. I have had bad results with even modestly past-dated Polaroid because the pod starts to dry out and causes uneven coating. My experience was with using films from an opened box -- some have said that the Polaoid instant films lasts longer if the foil seal isn't broken.

[Ole Tjugen]

Acetic acid (glacial) is NOT harmed by freezing. Indeed, even in a glass bottle it does no harm. This is because acetic acid, like nearly everything else EXCEPT water, contracts when solidifying.

My bottle of acetic acid freezes every winter (it's stored in the basement). Just warm it up gently, and no harm is done.

[Tom Westbrook]

Wow, Jim, you've had them since '91? Yikes! Have you tried any? I had two of the little pods leak after briefly freezing while I was out photographing in the cold last winter. Polaroid says not to freeze them, too, in this guide (1.2MB file) ,but not in the data sheet, oddly enough.

[RICHRRD ILOMAKI]

Why bother with ordereing Acetic Acid with all the handling hassles.

Just use water with a splash of plain white Food Grade vinegar, then dispose of it and use a fresh batch next time. It costs all of a dollar a gallon at the supermarket and that can be a year's supply.

Better living through chemistry!!

Cheers

[Pete Caluori]

Greetings,

In addition to using vinegar, if you don't like the smell, you could use citric acid. Citric acid is available as a dry powder from most health food stored.

Regards, Pete

[James Phillips]

This may come as a surprise to some... but I actually like the smell of acetic acid or should I say vinegar.

Kind Regards,