Refridgerating chemicals: Does it make them last longer?

[Dave Krueger]

Hello, all. I'm new to this forum and have a question I hope someone can answer for me. I did a forum search, but didn't find this issue specifically addressed.

Everyone knows film maintains its design characteristics longer if refridgerated, but what about chemicals? Is the shelf life of a full bottle of Xtol stock longer if refridgerated? Will it last one year? Two years? More?

Since I'm planning to experiment with a few new developers, it's unlikely that I will use them all before the end of their published shelf life. I have enough using up one developer before it's too old to use.

Any thoughts?

-Dave

[paulr]

I think it would probably help. Though in some cases the cold might cause some chemicals to precipitate out of solution. Especially if you're working with any liquid concentrates or formulas with barely soluble components (like phenidone).

Think twice about using coke bottles, salad dressing bottles, etc. ;)

[Chris Strobel]

Well I read Ansel Adams Polaroid book, and He says Type 55's shelf life can be extended when in the fridge, and from what I understand is its the chemicals in those pods that go bad first.Just a thought fwiw


Hello, all. I'm new to this forum and have a question I hope someone can answer for me. I did a forum search, but didn't find this issue specifically addressed.

Everyone knows film maintains its design characteristics longer if refridgerated, but what about chemicals? Is the shelf life of a full bottle of Xtol stock longer if refridgerated? Will it last one year? Two years? More?

Since I'm planning to experiment with a few new developers, it's unlikely that I will use them all before the end of their published shelf life. I have enough using up one developer before it's too old to use.

Any thoughts?

-Dave

[robc]

if they are powdered chemicals then it shouldn't do any harm providing they are fully sealed and air tight. But if they air and light tight, they shouldn't need to be in the freezer anyway. With liquids there are two problems. Firstly expansion can explode bottles when freezing and secondly, precipitation and or crystalization of chemicals which may or may not go back into solution when you unfreeze the liquid.

[Ron Marshall]

I wouldn't put any chemicals in close proximity to food, no matter how well packaged and labelled.

[Dave Krueger]

I think it would probably help. Though in some cases the cold might cause some chemicals to precipitate out of solution. Especially if you're working with any liquid concentrates or formulas with barely soluble components (like phenidone).

Uh-oh... From what I've read, Xtol is a phenidone/ascorbic acid developer. Guess I could put a liter of it in the refer and see if anything precipitates out. It would be visible, wouldn't it?


Think twice about using coke bottles, salad dressing bottles, etc. ;)

Who knows. It might make for a nice Ceasar salad... :D

[Dave Krueger]

I wouldn't put any chemicals in close proximity to food, no matter how well packaged and labelled.

I have a dedicated refer for film. It has a lot of extra space for chemicals, though.

[Dave Krueger]

if they are powdered chemicals then it shouldn't do any harm providing they are fully sealed and air tight. But if they air and light tight, they shouldn't need to be in the freezer anyway. With liquids there are two problems. Firstly expansion can explode bottles when freezing and secondly, precipitation and or crystalization of chemicals which may or may not go back into solution when you unfreeze the liquid.


I'm talking about having to mix 5 liters of Xtol stock at a time and using it kinda slowly (I'm not a prolific shooter). The data sheet on xtol is a little ambiguous about shelf life, apparently because of complaints from customers. I'd just like to be confident that it would last for more than six months and I thought refridgerating it might help. I have no plans to freeze it.

[robc]

most mixed chemical stock lasts for upto six months if its kept in full and tightly sealed bottles. However, if you are using that little then I would buy smaller pack sizes. Don't they make a 1 litre pack?

If not then mix and decant to 5 one litre bottles and keeping them in the fridge will help to prolong the life. Make sure the bottles are full right to the very top so that there is no air in top of bottle. If there has to be air in top of bottle, then use some of the canned inert gas to top up the bottles and drive out oxygen. Its better to have them really full. Make sure the bottles you use are truly air tight. Glass is best.

[cyrus]

There are various techniques to keep chemicals fresh. The biggest threats are heat and light. Putting the stuff in the fridge helps slow the deterioration, but not too cold. Most of the plastic bottles sold by photo stores are permeable to air so they're not great for long term storage. Glass bottles are great but can break, and to make sure that they're always filled to the top, you can put marbles in them to keep the liquid level high. There's an easier way: pop or soda bottles. They're designed to be impermeable to gas, they're cheap as heck, they can be squeezed to keep excess air out. The only problem is light so keep them somehwere dark like the inside of a cool fridge...
But the best bet is to use up the stuff and mix a new batch!

[robc]

and let the bottles stand open a little while before putting caps on so that all air bubbles from the mixing can come out of solution before capping.

[paulr]

Uh-oh... From what I've read, Xtol is a phenidone/ascorbic acid developer. Guess I could put a liter of it in the refer and see if anything precipitates out. It would be visible, wouldn't it?


sure, you'd see crystals forming, probably on the bottom of the bottle. i don't know for sure it would be a problem; why not try with something smaller than a litre?

[paulr]

a friend of mine had the coolest method for protecting his photo chems from air. aparently it was popular with 19th century chemists and pharmacists.

he'd keep the solutions in glass bottles, and displace all the air by dropping in marbles. he had a bunch of clear glass ones i don't know if were made for this, or for fish tanks or gardens or what. every time he used a bit more of a solution, he'd drop in a few more marbles.

it's so simple and so perfect ... i even thought of using it to preserve half-drunk bottles of wine.

maybe for the wine use different marbles than the ones you used in the mercury intensifier or the uranium toner.

[Dave Krueger]

sure, you'd see crystals forming, probably on the bottom of the bottle. i don't know for sure it would be a problem; why not try with something smaller than a litre?

I could try something smaller. It's just that I plan to mix up five 1-liter bottles of the stock.

How long would it take for the crystals to form? Is it something that might take an extended period of time?

I noticed that pyrocat HD has phenidone in it, too. That was one of the other developers I was planning on trying, but since the stock is a glycol solution, I wasn't planning on refridgerating it.

[Dave Krueger]

a friend of mine had the coolest method for protecting his photo chems from air. aparently it was popular with 19th century chemists and pharmacists.

he'd keep the solutions in glass bottles, and displace all the air by dropping in marbles. he had a bunch of clear glass ones i don't know if were made for this, or for fish tanks or gardens or what. every time he used a bit more of a solution, he'd drop in a few more marbles.

it's so simple and so perfect ... i even thought of using it to preserve half-drunk bottles of wine.

maybe for the wine use different marbles than the ones you used in the mercury intensifier or the uranium toner.

I like the marble idea, even for plastic bottles. I noticed B&H only has the gallon size air-evac bottles in stock these days. You have to go elsewhere for the 1/2 gal and quart size.

I read a discussion somewhere about glass versus plastic (probably on here somewhere) and I plan to stick with plastic.

As for the wine, I completely agree that it's probably a good idea keeping the apocalyptic glow-in-the-dark photo chemicals away from it. LOL!

[Dave Krueger]

and let the bottles stand open a little while before putting caps on so that all air bubbles from the mixing can come out of solution before capping.

Good idea. You know, I've often wondered about letting the water I use for developers stand for a while before mixing it. I use filtered water, but I suspect it has a lot of tiny air bubbles it it just like tap water.

Maybe for some of these new developers (especially stuff like pyrocat) i shoud switch to distilled water...

[paulr]

How long would it take for the crystals to form? Is it something that might take an extended period of time?

They should form pretty quickly if they form at all. Give it overnight to be on the safe side. This is all just because the solubility of a solution goes down with temperature. If you're working with a concentrate that's close to the saturation point at room temperature, than putting it in the fridge will lead to oversaturation and to the chemical precipitating out.

I only bring up phenidone because it has very low solubility in developer solutions ... so concentrated stock solutions of phenidone-based developers can be close to the saturation point.

The formula i use starts with a concentrate that has 2g of phenidone per liter. The formula relies on diethylene glycol just to get this amount of phenidone to disolve at all. I find that i get some precipitation in the winter time without any refrigeration, so I assume the frige would not work so well with this formula. But with less phenidone, or a stronger solvent, you might be ok.

[Peter Galea]

There's an easier way: pop or soda bottles. They're designed to be impermeable to gas, they're cheap as heck, they can be squeezed to keep excess air out. The only problem is light so keep them somehwere dark like the inside of a cool fridge...

If you have kids, or someone elses kids might have access...NEVER put chemicals into a soda or drink container.

[Dave Krueger]

If you have kids, or someone elses kids might have access...NEVER put chemicals into a soda or drink container.


And I suppose you're next going to tell us that we shouldn't let our kids play with those plastic bags that come from the dry cleaners... ;-)

[Peter Galea]

And I suppose you're next going to tell us that we shouldn't let our kids play with those plastic bags that come from the dry cleaners... ;-)
No, those plastic bags are fine toys....for your kids.
I'm a pest control operator. People put stupid things in drink containers.
Children are poisoned.
If you don't have anything to add to the thread...don't.
Oh, I forgot, this is the internet.

[Dave Krueger]

No, those plastic bags are fine toys....for your kids.
I'm a pest control operator. People put stupid things in drink containers.
Children are poisoned.
If you don't have anything to add to the thread...don't.
Oh, I forgot, this is the internet.

I started the thread. It's about the effects of refridgerating chemicals. It's not about how to be a better parent. Your comment was not a subtle suggestion or a comment. It was preaching as if we're all a bunch of idiots. I, for one, didn't care for it.