Inflating balloon to expel air from developer concentrate?

Allan Reade

Allan Reade

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I've recently begun developing BW films and use ID11 because it's cheap and readily available here. At 1:3 the litre of concentrate may last me a few months. I've tried squezing the bottles to eliminate air with limited success, then small marbles. How about inflating a balloon to expel almost all the air? Is the rubber liable to be attacked by the developer and so spoil the developer?
Thanks for any advice.
Allan
 
Leigh Youdale said:
. I think CJC's idea of "canned air" sounds better. From memory it's actually compressed nitrogen gas and displaces the the oxygen-rich air.
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When we exhale, that's mostly CO2, right? Anyone know if it's anywhere near pure CO2. Why couldn't we just exhale into the bottle?
 
wgerrard said:
When we exhale, that's mostly CO2, right? Anyone know if it's anywhere near pure CO2. Why couldn't we just exhale into the bottle?
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No. What you inhale is about 21% oxygen and 0.04% CO2. What you exhale is about 15% oxygen and 4-5% CO2. It's not enough difference to have an effect. When CO2 dissolves in water, it makes carbonic acid in equilibrium with other dissolved components, but this, if sufficiently strong, could change the pH of the alkali in the developer. What you need is pure nitrogen gas (like wine saver) or a noble gas like helium.

If you can get helium and actually fill the space with it (it's a lot lighter than air) it should work. But D76 or ID11 should be fine over a few months.

Marty
 
Freakscene said:
No. What you inhale is about 21% oxygen and 0.04% CO2. What you exhale is about 15% oxygen and 4-5% CO2. It's not enough difference to have an effect. When CO2 dissolves in water, it makes carbonic acid in equilibrium with other dissolved components, but this, if sufficiently strong, could change the pH of the alkali in the developer. What you need is pure nitrogen gas (like wine saver) or a noble gas like helium.

If you can get helium and actually fill the space with it (it's a lot lighter than air) it should work. But D76 or ID11 should be fine over a few months.

Marty
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What if you hold your breath until you nearly pass out ... how much oxygen would be left then?

If you don't know the answer here Marty I'll be disappointed! 😀
 
What is even more important is that most tops leak, if you have concerns, put Saran Wrap under the cap, it is denser than the others, and I find the chemistry lasts far longer.

I have a few glass stoppered bottles, those really work well, but are hard to find, the stoppers were ground to match the bottles.

Inert gases, --Argon is the third most common gas in the atmosphere, might be the cheapest, now if you can only get it out of the light bulbs. ;-)

Biggest hoax was the accordion bottles, they increased the surface area of the bottles.

I used to sell stoppers, the best leak, without Saran Wrap.

I used to use only glass bottles, but found the plastic chemistry bottles used for Kodak's chemistry (ask a one hour lab to save some for you, think they are 5L) were sold by BH and when properly sealed seemed to keep the soup fresh.

I have seen the bottles of wine preserving gases sold at Trader Joe's, seem to work for wine.

Most Balloons also pass air, so probably not worth the effort.

Regards, John
 
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Thank you all for your replies.

While it is true that holding my breath for long enough will make the problem go away, I will try to find a solution I can live with 🙂

More marbles are probably a good start.

Allan
 
Allan Reade said:
I've recently begun developing BW films and use ID11 because it's cheap and readily available here. At 1:3 the litre of concentrate may last me a few months. I've tried squezing the bottles to eliminate air with limited success, then small marbles. How about inflating a balloon to expel almost all the air? Is the rubber liable to be attacked by the developer and so spoil the developer?
Thanks for any advice.
Allan
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That's not a bad idea. But I think your best bet is to store the solution in smaller bottles (if you mix up a litre, store it in two half litre bottles) or use a bigger tank with a floating lid. When I worked in a pro lab we used to mix up 20+ gallons at a time and store it in tanks with small chemical-resistant plastic balls that floated and completely covered the surface. We stopped using the solid floating lids, because they always seemed to become submerged. Not sure where to get those floating balls, though.


/
 
visiondr said:
Marbles, my friends, marbles; cheap, easy, effective, environmentally responsible.
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Exactly. They're available in the big box discount stores, usually somewhere near the fish tanks or floral arranging supplies. Just wash them off well and, obviously, make sure they'll fit in the bottle you're using. No huffing, no puffing, and no trying to squirt canned air into a bottle. Ideal.
 
Keith said:
What if you hold your breath until you nearly pass out ... how much oxygen would be left then?

If you don't know the answer here Marty I'll be disappointed! 😀
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If you hold your breath longer, the amount of CO2 decreases due to diffusion back the other way.

Marty
 
I think Mr Free's balls might not have floated... Given that he was doing 150mph on a salt flat, the possible consequences of even the most minor of abrasions had he come off are eye-watering just to think about. No, I think Rollie had balls of steel!

Anyway, it's an excuse to post this...

http://www.youtube.com/watch?v=AxKTzwaEa2o

Adrian
(Hmm, I wonder how my fixer and stop bath are, given that I think I made them up in April... just to keep us on-topic!)
 
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