Storing Chemicals under Nitrogen

[Brandon Draper]

I recall reading somewhere that you can use canned air instead of nitrogen to keep your chemicals longer. Is that true? Since trying to find the Tetenal protectant spray is impossible.
I want to mix smaller quantities of E-6 chemicals.

Thanks

[paulr]

A friend of mine had a great, simple solution to oxidation. he got it from 19th century chemists.

He kept his chemicals in glass bottles, and took up all the extra air space in the bottles by dropping glass marbles in. I have no idea why this hasn't caught on (I admit I never tried it myself ...).

Seems like it would be perfect for keeping half-finished bottles of wine, too. But you might want to keep the wine marbles and the developer marbles in different jars ...

[Stpephen Willlard]

I had tried using nitrogen, but for some reason I did not find it very effective. I used some made by Tetenal and came in a
spray can.

Since then I have resorted to using clear decorative marble. They work great! If you go to a toy store a buy clear marbles
they will cost you a fortune. The decorative ones at hobby stores are real cheap. Get the ones that are smaller in size so
you can use a funnel. I bought a funnel specifically for this and cut the tapered stem short so that the marbles could just barely
pass through. I also bought a stainless steal colander that is designed to hang in the sink. I dump the marbles into the
colander when I am though and rinse them out. I then store in a net bag so that air can circulate and dry them out.

I use the marbles for C41 film chemistry and RA4 print chemistry. Both developers I store in liter bottle, and they will oxidize real
easily if the bottles have any air. I fill the bottles just shy from the top and then squeeze the side to take out the remaining air be for I seal them with the cap. It is important that you use non-osmotic plastic bottles otherwise air will pass through the bottle walls in the same a balloon filled with helium will start to fall over time.

Hope this helps.

[Chris Gittins]

I use Dust-Off in my developer bottles (D-76, DD-X, and Dektol). It works like a charm.

[Pete Caluori]

Greetings,

Tetenal Protectan is either no longer being made, or no longer being imported into the US - I forget which. Nitrogen would work just fine if you could find a way of delivering it with low pressure and volume. Protectan was largely butane and you could probably substitute the refils for butane lighters. Needless to say butane is flamable as was Protectan.

Regards, Pete

[Steve Baggett]

I currently use nitrogen from two 80-cu-ft tanks to "top off" all my E6 and C41 chemistry, especially the partially full, unmixed bottles in the "kit". It works well for me. You have to flush each bottle for about 10-20 seconds depending on flow rate and the amount of "space" in the top of the bottle. The startup costs were heavy though (nearly $200 USD) for the tanks and regulator. Refill (exchange) for each tank is about $14 USD and each tank lasts about 3 months. I kept one Kodak E6 kit (about 1/2 used) under nitrogen for about 5 months and it was "good as new" when I finally used it again. Nitrogen is what is used to fill the space in the bottles when shipped from the manufacturer, so it's good enough for me.

[Michael S. Briggs]

From the MSDS, Tetenal Protectan was a mixture of propane and butane. The advantage of these chemicals is that they will condense into liquid under pressure and so more can be fitted into a can at a reasonable pressure. Its either no longer made or no longer shipped to the US -- my guess from a reassessement of the hazzards of shipping many cans.





Almost any gas without oxygen will can be used as a preservative. Wine stores sell products that are mixtures of nitrogen, carbon dioxide and argon. A very similar product, Bloxygen (http://www.bloxygen.com/), is sold for preserving wood finishes. These might be good choices for those who don't want to buy a cylinder of high pressure nitrogen. I suppose that the carbon dioxide might change the pH of a solution, but if the amount doesn't effect wine, it shouldn't effect any photographic solution with even a small amount of buffering.





Many plastic bottles, even some sold for photographic purposes, are permeable to oxygen. I find chemicals keep better in glass bottles.

[Mark Sampson]

Nitrogen "blanketing" is the basic principle behind the Wing-Lych processors. Interestingly enough, they use nitrogen under pressure to pump the chemistry into the processing trough too. It works quite well for both E6 and b/w.

[Steve Clark]

I`ve been using nitrogen as a replacement for "Dust Off' for several years now with excellant results. My initial reason for going to nitrogen was that I needed a burst of air large enough for 5X7 negs. , hadn`t really thought about preserving chems with it. A local welding supplier set me up with a used regulator, in as new condition, with a tank, for about $100.00 USD, It has more than paid for itself. Recently, I`ve started using it also for processing 120 film on spiral reels, so far it seems as though my edge density problems have been eliminated. Next project?, 4X5 and 5X7 films with nitrogen burst agitation. Rather than have a high pressure cylinder unsecured in the darkroom, the tank is secured in a central location with a long enough light weight hose to reach both wet and dry sides easily.