Argon gas to preserve developers

David Brown · Nov 20, 2017

I've seen a product called "Bloxygen" mentioned here to use in prolonging the shelf life of photochemicals. The product's website specifically mentions "photo chemicals" although it is primarily marketed for wood finishes.

Anyone use this? Experiences? Tips?

I have not (in almost 50 years) had any real problems with developers going bad, but I am doing less darkroom work these days, and would like my track record to continue.

Thanks.

http://www.bloxygen.com

AgX · Nov 20, 2017

Basically you can use any inert gas. Benefitial though would be if it is not toxic, non flamable, heavier than air and cheap.

Look through what your local industrial gas supplier offers and make up your mind. But you won't find a gas that yields all features..

bdial · Nov 20, 2017

I used bloxygen until I found a cylinder of nitrogen on craigslist.
It seems to work, but I never tried any controlled tests, but no issues with chemistry going bad that I could pin on its use.
The biggest problem I had with the bloxygen is that it's hard to tell when it's empty. I think using mail order suppliers would be a good idea, vs bricks-and-mortor retailers, so that there is no potential issue with people "sampling" it.

WilmarcoImaging · Nov 20, 2017

An easier solution in my view is to use PET bottles for storage, if not already using them or glass. PET bottles are highly oxygen resistant, and when the developer is stored at brimful, offers excellent shelf life. PET bottles are available in several sizes which can be tailored to the volume of liquid to be stored.

AgX · Nov 20, 2017

PET is not stable against all alkaline solutions. We had here at Apug repeated reports of cracking.

WilmarcoImaging · Nov 20, 2017

Interesting AgX, I wasn’t aware of that. Will have to read the posts to learn more.

Tony-S · Nov 20, 2017

I just use a bladder from an old 5 liter wine box. Keeps my XTOL good for more than a year.

pthornto · Nov 20, 2017

Argon is in many ways the ideal lab gas, as it is inert and its density allows you to blanket your solution with the gas and it won't immediately disperse up and away. It is expensive though so unless you absolutely need it, nitrogen is much more economical. I've never found purging a headspace in a bottle to be neccessary for developers though...minimizing the headspace and using glass or PET are best strategies.

Patrick Robert James · Nov 21, 2017

I tried a spurt of Butane in a half full glass bottle with Ian's Ilford version of Neutol WA. After a few months it was still clear. Usually at that point it is a darker color. Curious to know what others think of that.

mshchem · Nov 21, 2017

Patrick Robert James said:
I tried a spurt of Butane in a half full glass bottle with Ian's Ilford version of Neutol WA. After a few months it was still clear. Usually at that point it is a darker color. Curious to know what others think of that.

I've used butane with excellent results, purely empirical, no controls. The Tetenal material is, I believe a blend of propane and butane. Butane is denser than air so that helps.

mshchem · Nov 21, 2017

WilmarcoImaging said:
Interesting AgX, I wasn’t aware of that. Will have to read the posts to learn more.

Yes, I use a lot of brown PET bottles for dilute solutions. I split some 3 bath Tetenal E6, the color developer destroyed my cute little PET bottles. From now on all I buy are HDPE. I still use my 1L, 500, 250, and 125ml PET bottles for dividing XTOL and Bromophen stock no problem. I found a bottle of XTOL stock that I had misplaced, over 10 years old! Still worked perfectly fine. It was stored in a PET soda bottle with the air squeezed out.
Best Regards Mike

Gerald C Koch · Nov 21, 2017

For what you might save by using an inert gas you could just as well dump the oxidized developer. The only one that would profit from this idea is the guy selling the gas. Developer is cheap even if you have to toss some.

AgX · Nov 21, 2017

If it gets to colour processing for quite some of us obtaining the processing baths is expensive and troublesome in relation to b&w.

David Brown · Nov 22, 2017

Gerald C Koch said:
For what you might save by using an inert gas you could just as well dump the oxidized developer. The only one that would profit from this idea is the guy selling the gas. Developer is cheap even if you have to toss some.

You may be right. Hence, why I was making for others' experience.

lantau · Nov 22, 2017

Maybe someone will have a better scientific argument to disprove me, but by covering the head space with inert gas,such as butane, you will reduce the partial pressure of oxygen. Essentially you should drive some dissolved oxygen into the head space. So this should be much better than glass beads, which will not change partial pressure.

Gerald C Koch · Nov 22, 2017

If you calculate the amount of air in the bottle and the amount of oxygen in it and the amount of developer that will be oxidized you will find that why bother. You will pay more for the gas than the the effected developer. Just toss it and feel good that you have made the best economic decision. Of course the very best decision is not to mix up more developer than can be used in a reasonable time.

AgX · Nov 22, 2017

There are various inert gases to chose from and various ways to handle them, each approach has its own economic balance, one should not generalize.

Kawaiithulhu · Nov 22, 2017

Gerald C Koch said:
pay more for the gas than the the effected developer

Which means nothing if your soup goes bad and you have to take extra time to make more when you find out, all of which could have been prevented.
How much is your time and frustration-free darkroom experience worth?

hoffy · Nov 23, 2017

Gerald C Koch said:
If you calculate the amount of air in the bottle and the amount of oxygen in it and the amount of developer that will be oxidized you will find that why bother. You will pay more for the gas than the the effected developer. Just toss it and feel good that you have made the best economic decision. Of course the very best decision is not to mix up more developer than can be used in a reasonable time.

BUT..... Would I be right in saying that there is no need to remove all the atmospheric air in a bottle? All you need to do is provide a blanket of inert gas to cover the surface area of the liquid, especially if the bottle is being stored upright and stationary?

BMbikerider · Nov 23, 2017

As a rider to storing developer in glass bottles,I have mentioned this before and that is to fill the glass bottles but before capping them heat them in a microwave which will expel a lot of the air as it expands. Cap securely when hot and as it cools the bottle will form a partial vacuum and a consequential reduction in oxygen, which is the real developer killer.C41 developer has lasted over 6 months and more when treated this way. This pretty well what happens when you boil a kettle, all free oxygen in the water is dispelled.

AgX · Nov 23, 2017

hoffy said:
BUT..... Would I be right in saying that there is no need to remove all the atmospheric air in a bottle? All you need to do is provide a blanket of inert gas to cover the surface area of the liquid, especially if the bottle is being stored upright and stationary?

No, over time gases diffuse into each other to form a homogeneous compound.

Gerald C Koch · Nov 23, 2017

hoffy said:
BUT..... Would I be right in saying that there is no need to remove all the atmospheric air in a bottle? All you need to do is provide a blanket of inert gas to cover the surface area of the liquid, especially if the bottle is being stored upright and stationary?

This is a popular msconception. Unless the gas is very heavy, which is usually not the case, it will briefly fall toward the bottom of the bottle. However thermal motion will quickly disperse any gas regardless of specific gravity throughout the available space. In addition the force with which the gas enters the bottle does a pretty good job of mixing things up.

Gerald C Koch · Nov 23, 2017

ALL OF THESE 'SOLUTIONS' ARE IN RESPONSE TO A NON-EXISTANT PROBLEM. Most developers are rather cheap and all the money and time spent trying to protect it is a waste. If you wish to save a bit of money then only mix or buy enough developer that can be used in a reasonable time that is within its expiration time.

Argon gas to preserve developers

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