Darkroom - prevent oxidation in chemistry

[Photoemulator]

A number of years ago, there was a thread about using an inert foam lid to prevent the chemistry from oxidizing too quickly in large reservoirs. I was thinking about water bags or even, if you have a tank with a lid on top, floating some foam there. Does anyone have experience or other suggestions???

 

[Petrochemist]

I believe the usual approach is to use concertina bottles & expel the excess air after use. It's the only approach I've used in the darkroom.

For more reactive compounds in the lab we would store them under nitrogen & extract reagent via a syringe without opening the bottle. I don't think that's necessary for photo reagents

 

[Old_Dick]

For those of us whose Bordeaux collection will outlive them, nitrogen spray in a can. When we cannot finish a bottle, which is always, use nitrogen in a spray.

À votre santé

 

[wiltw]

CO2 is heavier than air...you could blow that into the bottle before capping it. CO2 is cheaply available for making sparkling water!

 

[DREW WILEY]

I'm experimenting with pure argon canisters, sold for wine preservation purposes. I purchased the least expensive version, Airgone; but another conspicuous brand is Bloxygen.

 

[cliveh]

I just use empty plastic drink bottles (washed out) and scrunch them up as developer is used to keep the level of liquid at the top.

 

[mshchem]

Floating lids are used in large tanks. Kodak made 1/2 up to 3 1/2 gallon hard rubber tanks with floating lids. Doran/Premier make round storage tanks 2 to 5 gallon with a floating lid and a separate dust cover. These work great. Look at B&H for storage tanks etc.

 

[mshchem]

I just use empty plastic drink bottles (washed out) and scrunch them up as developer is used to keep the level of liquid at the top.

+1+1+1

 

[mshchem]

Greatest thing ever

https://www.bhphotovideo.com/c/product/43191-REG/Doran_PRPRT2_Chemical_Storage_Tank_2_Gallon.html

 

[cliveh]

Another good method is to buy a box of wine and when empty take the bag out of the box, remove the tap and wash it out. Then fill with chemical, replace tap. Cut the box to reverse it inside out and replace bag and mark box with contents. Hey presto, container with spring loaded tap to avoid wastage and bag collapses as used.

 

[Sirius Glass]

The solution that I use is StopLossBag™ with their funnel. I use the 1 liter bags. www.StopLossBags.com

 

[brian steinberger]

CO2 is heavier than air...you could blow that into the bottle before capping it. CO2 is cheaply available for making sparkling water!

+1.

I hold my breath and exhale into my amber glass bottles before capping. Been doing it for years.

 

[MattKing]

I believe the usual approach is to use concertina bottles

I recommend against these bottles as strongly as possible.
They are extremely difficult to remove residue from, and they often start leaking through the folds.

 

[jk0592]

I am another fan of StopLoss bags. They are efficient once the air has been expelled, which is easy to do.

 

[DREW WILEY]

Over the long run, all those thin plastic camera store style containers prove permeable to oxygen. Actual glass is way better, or at least thicker virgin plastics designed for serious chemical storage.

My no. 1 culprit is Part B of RA4 developer concentrate, which goes bad before the other components once it's opened. Being able to preserve this over a few months of color printing inactivity would save me a lot of money. They don't sell this specific component by itself anymore.

And I can't exhale into these kinds of solutions or even work in proximity to them without highly effective fume exhaust ports directly above the bottles themselves. They're not like ordinary B&W chem.

 

[Klaus Mähring]

Floating lids are great. Plus some anti-oxydation gas.

But another source of oxydation is often overlooked: Mixing and pouring the chemicals. When mixing I take care not to stir to hard, and without mixing in air. When pouring, I try to never pour chemicals from the top. Instead I use a funnel with a hose attached so the chemistry goes 'underneath' without a lot of bubbling....

 

[koraks]

another source of oxydation is often overlooked:

Because it almost certainly isn't very significant at all. You spend a relatively short period of time mixing the chemistry and there's only a very limited amount of oxygen that will manage to dissolve in the water during that time.

 

[gbroadbridge]

I just use empty plastic drink bottles (washed out) and scrunch them up as developer is used to keep the level of liquid at the top.

Exactly what I do.

Concertina bottles are impossible to clean properly.

 

[Alan Johnson]

Best Plastic for Chemical Storage

I recently discovered that some of my bottles were "Type 7" plastic, not suitable for storage. Everything that went in them went bad: Dektol, Fixer, it all turned brown. I finally caught a clue and dumped them in the trash. My wife was throwing away one of those large, liquid laundry...

www.photrio.com

 

[Don_ih]

I don't worry about it. I gave up having more than a litre of a developer hanging around. And I do what @cliveh said, above, squeezing air out of thinner plastic bottles.

 

[naaldvoerder]

+1.

I hold my breath and exhale into my amber glass bottles before capping. Been doing it for years.

Is this true? Or irony?

 

[Klaus Mähring]

Because it almost certainly isn't very significant at all. You spend a relatively short period of time mixing the chemistry and there's only a very limited amount of oxygen that will manage to dissolve in the water during that time.

It does play a role if you fill & empty your processor quite often....

 

[DREW WILEY]

Maybe it's garlic on the breath which is the actual preservative.

 

[halfaman]

I use amber glass bottles filled to the top. I have several sizes from 2,5 liters down to 25 ml to be sure that I can always store it that way. I am able to keep reasonable well C41 developer for close to three years.

 

[koraks]

It does play a role if you fill & empty your processor quite often....

That doesn't involve a lot of stirring, though, and it's unavoidable that there's some (limited) exposure to air.

I use RA4 color chemistry in a processor, replenished, never discarded. Works OK. Apparently it survives. Of course, it's formulated to tolerate considerable exposure to air in its intended application. Trying to use dilute Pyrocat HD or something like that similarly would of course end up being a massive disappointment. The morale is that as long as you do something that's sensible to begin with, it'll sensibly work out...

I'll leave the splitting of hairs to hairdressers; it's not my department.