Mixing developer in high concentration for longer life

Hi all,
If I mix powder developers in a higher concentration, would I get longer shelf-life?
For example, mixing a can of Microdol-X (1 gallon) in a 1/4 gallon of water.
Of course I will make up that extra water when I dilute to make working solution.
I don't shoot B&W films much these days ... and I have a few cans of Microdol-X ... and a few packs of 5L Xtol ...

Cheers
Edward

The problem that you are likely going to encounter is the limited solubility of sodium sulfite. Assuming that microdol has 100g of sulfite per liter as does D-76 you will not be able to make up a 4x concentration, since the solubility of sulfite is about 125g per liter.

Jurgen

I'm guessing many company's just-add-water powdered developers won't tolerate mixing in very much more concentrated strength than manufacturer's directions, or they would have suggested just that.

I do it wherever possible.

A 2x concentration kept in full-to-the-cap glass bottles has an indefinite shelf life for most of the developers I've used over the past 50 years.

It's easy to mix 1 gallon of powder into 1/2 gallon of water if you're patient and use a bit (±90 degrees) of heat.
I have a little hot plate and a common stainless 6-quart cooking pot just for this purpose.

Reinhold

www.classicBWphoto.com

Thanks all.

Just after I posted, I tried mixing Mic-X in a 1/4 gallon of water.
Damn hard. Solids refused to disolve so I added another 1/4 gallon of water. Bingo

Reinhold said:

.. indefinite shelf life for most of the developers ...

Click to expand...

Thanks Reinhold, that's the answer I want to hear

I mix Selectol Soft near 2:1, basically mixing 2 1gal packets into 5L. I then generally dilute 1+2 or 1+3 when I use it. One could probably cram 3 1gal packets into 5L if they try hard enough.

Ilford ID-3 is the same as Kodak D165/Selectol Soft and Ilford gave two different dilutions the first as a single solution Developer, the second as a two part developer with a far longer shelf life, in use they are identical.

ian

Thanks for good info guys.

So, is it safe to assume that my recently mixed Microdol-X (2xconcentration) has longer shelf life?
Any idea how much longer?
12 month is good enough for me.

You may gain a slight increase in shelf life, but where developers are split to separate the alkali from the developing agent(s) you get the greatest improvement. That's not feasible with Microdol-X.

Ian

Keep the developer in smaller (one pint) clean, full-to-the-cap glass bottles. Top off the bottle with inert gas after each opening.
You'll get 12 months storage easily.

Guaranteed.
Double your money back.

Reinhold

www.classicBWphoto.com

I also wanted longer shelf life and my solution for solutions was to store the mixed stock in smaller bottles. I was first going to use plastic water bottles but, partly due to safety issues found a better way.

I purchased 250ml Amber Glass Large Mouth Bottles to be able to mix up Xtol (20 bottles) or D76 (16 bottles) and store in smaller bottles with no air so it would last longer. Then I could use one shot or 1:1.

I also think its a good idea as an added precaution to put a Saran wrap seal on before the screw top.

I ended up buying hundreds of bottles (long story) and have been selling the (there was a url link here which no longer exists). If your interested in trying some, let me know.

I have a past post about a weird experiment I ran with microdol x. I dissolved the 1 gal size in 1L of warmed to 28C propylene glycol, and then decanted the liquid off of the slush of the sulfite left in the 1 gallon stainless tub I was mixing it in, then let the remaining prop glycol drip though a coffee filter to capture as much of the liquid, and in turn the dissolved developing agents, from the wet sulfite slush. I then kept the prop glycol as the A, which had dissolved most of the developing agents. I added enough hot water to the sulfite slush until it was fully dissolved, and made that the B.

My Microdol X made this way is still viable 2.5 years after this experiment was begun. Once reconstituted as A+B plus a bit of water it lasts about 3 months.

It has a need for extra time to develop a film to the same CI as fresh mixed only with water Microdol X, even from when it was first mixed in the A+B stock solutions, so I have had to develop new time temperature charts for it used this way. It suits me though, because I really don't use Microdol very often, but know that it will give me the look I want when I want it.

Excellent information guys, much appreciated.

I have a few 1L accordion bottles that I am going to store the stock.
1/2 gallon of 2xconcentrated microdol-X filled 2 bottles. I can squeeze out the air until last 300mL.

Fotch, that's good idea to have it in small bottles. I will think about it and let you know if I want them.

Mike, interesting experiment. However, isn't sulfite a preservative that slow oxidising? If you separate majority of sulfites from the first solution wouldn't it oxidise quicker?
My knowledge on chemical composition and reactions of the developers is very shallow so I am quite happy to be corrected if I am wrong.
I also use Xtol a lot and as we know it comes in 2 packets. If I mix 2 packets separately as part A and part B, would I be able to use it longer?

eSFotos, I just checked, shipping to Australia would be big bucks. An alternative would be find similar size (250ml) plastic (PET 1) bottles or glass, just to be sure to label them. I use to use accordion bottles years ago but usually used up developer in 2 months or less. If anything was left in it for say 6 months, didn't look right when poured out so I would just dump it.

I think filled to the brim, small bottles is the way to go. JMHO

eSFotos said:

Mike, interesting experiment. However, isn't sulfite a preservative that slow oxidising? If you separate majority of sulfites from the first solution wouldn't it oxidise quicker?

I also use Xtol a lot and as we know it comes in 2 packets. If I mix 2 packets separately as part A and part B, would I be able to use it longer?

Click to expand...

Well the first dissolving solution, glycol. is water free, so no dissolved oxygen, if stirred carefully.

I'm not very used to xtol. No guarantee that A and B both have preservatives when mixed.

Those accordion bottles have a poor reputation.
They're a soft polyethylene which is a relatively ineffectual oxygen barrier.
I threw mine away years ago...

You'd be better off using a common PET water bottle and squeezing the sides in.
PET has far better oxygen barrier properties.
But that's a bit clumsy and ideal only as a temporary solution.

Glass is the far better long term storage solution.

Reinhold