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  1. #11
    bowzart's Avatar
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    Quote Originally Posted by tkamiya View Post
    I just found out, my less than half full bottle of Dektol and XTOL solutions have the appearance of air being sucked out. That is, the plastic bottles have significantly caved inward.
    I have used wine boxes emptied of wine and rinsed out very well. The mylar bag inside is supposed to collapse when fluid is drawn out. If filled completely full before restoring the cap, there is little or no air to begin with, and the material is so airtight that I've been able to store chemistry, even color developers, often for years. When I started doing this, I couldn't believe how effective those things are.

    It seems that the best boxes come with the cheapest and most horrible wine which I can't stand (Franzia had the good boxes), so I did some searching around and found this:

    http://www.survivalsolutions.com/store/product41.html

    These are very economical, and conveniently hold one gallon rather than five liters. They have the most useful caps, and have the right kind of bags - the silver mylar ones.

    I have sometimes had fixer go bad, but very rarely. When it does go bad, it has been commercial ammonium thiosulphate fixer, which is very concentrated. You don't have to open the container at all; if you wait long enough it will throw down a whole lot of white precipitate. I'm sure that sodium thiosulphate fixer will go bad eventually as well if mixed and stored, but essentially, it's nothing to worry about, within reason. It will last much longer and remain useful, in general, than the manufacturers say. At least, it has always done so for me. Just check it once in awhile. A good way to do that is to see if it will clear a small clipping of film. The leader that is cut off the 35mm roll when loading the tank is perfect for this; doesn't matter if it has been exposed. The test? Does it clear, or doesn't it?

    Developers contain reducing agents which are needed to reduce the silver halides to metallic silver. The reducing agents oxidize during the development process. They are supposed to oxidize, because reduction does not take place unless the other party to the reaction oxidizes. They oxidize quite readily with the oxygen in air as well as with silver bromide. Developers are much more susceptible to spoilage for that reason. Fixing doesn't involve that type of reaction; the fixer dissolves the unexposed halides, leaving nothing in the film that can be reduced, and clearing the film.

    I'm oversimplifying of course, but these methods have worked for me for almost fifty years.

  2. #12

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    Although Dancqu loves single shot fixers, I prefer using two-bath fixing. I prepare two 1 liter bottles of fix, and then I write Fix 1 on one bottle and Fix 2 on the other. I then fix the film for 1/2 the time needed to fix with each bottle. I use fixer test solution (a potassium iodide solution) and then I test the first bottle and then when it becomes exhausted, I dump it out, replace the contents with the contents from Fix 2, and then prepare a new liter of fixer for Fix 2. It really is the most efficient way to use your fixer. A lot more effience than single shot fixing from commercially prepared fixers.
    Kirk

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  3. #13

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    Thank you very much, everybody!

    I think I have my system worked out now... It's a combination of everybody's method.

    XTOL - mix 5 liter -> 1/2 gallon tank full, 1/4 gallon tank full, 1/4 gallon COLLAPSIBLE tank (rotate as necessary)
    DEKTOL - mix 1 liter -> 1/4 gallon COLLAPSIBLE tank
    FIXER - mix 1 liter -> 1/4 gallon tank (check as needed with film clipping)

    I don't need this much XTOL but it only comes in 5 liter bag or larger in US market.
    (I see in Japan, there is a two liter bag. In US, Kodak seem to have eliminated 1 liter bag when sudden failure of solution became an issue and improper packing of 1 liter bag was a suspect)

  4. #14
    Akki14's Avatar
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    Just to let you know, the chemicals didn't "suck" anything - there was a radical difference in air pressure between when you closed the bottle and now. Like, if you close the bottles when it's stormy out, when it's a bright sunny day they'll collapse inwards a bit due to the higher atmospheric pressure.

    Also this means your bottles are rather air tight, in my opinion.
    ~Heather
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  5. #15

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    When something oxidize, doesn't oxygen combine with whatever and therefore, there is less oxygen in the air in the tank reducing the total amount of air in the tank?

  6. #16
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    Quote Originally Posted by tkamiya View Post
    When something oxidize, doesn't oxygen combine with whatever and therefore, there is less oxygen in the air in the tank reducing the total amount of air in the tank?
    Net amount of materials still in bottle, though. There would be no change.

    Except if there was a pressure change containing the materials more tightly into the same space (like a vacuum does).
    ~Heather
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  7. #17
    Akki14's Avatar
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    Also realise that oxygen makes up a small percentage of the air we breathe so the amount used in oxidation is very small and would not cause a change as you describe.
    ~Heather
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    http://www.stargazy.org/

  8. #18
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    In a closed container, there is an equilibrium between the pressure of the gas in the bottle and the vapor pressure of the liquid. The vapor pressure of the liquid can change considerably with changes in ambient temp. Thus causing the plastic bottle to 'cave in' when it is cold and 'bulge' when it is hot.

  9. #19
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    The bottle "collaspes" because about 21% of the gases originally in bottle no longer exist as a gas (the air we breathe is 21% oxygen). The oxygen has been removed from the air and has combined to form new chemical compounds that are not in the form of a gas. This reduces the pressure inside the bottle (by about 20%), causing the greater atmopheric pressure outside the bottle to push in the sides of the bottle.

    Vaughn

    Assuming the bottle is at room temp when the cap was put on and the bottle is stored at room temp, there would be very little bulging or caving in due to changes in vapor pressure.
    Last edited by Vaughn; 10-17-2009 at 01:13 PM. Click to view previous post history.
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  10. #20

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    Quote Originally Posted by Akki14 View Post
    Net amount of materials still in bottle, though. There would be no change.

    Except if there was a pressure change containing the materials more tightly into the same space (like a vacuum does).
    It's true that the total mass of materials in the bottle is the same before and after. But the oxygen consumed in the reaction has gone from being in the air to being in the liquid, and it has changed volume. As Vaughn points out, you start with a not so small 21% oxygen in the air and it drops as the oxygen gets consumed by oxidizing the developer or sulfite in the solution. And that changes the number of molecules left in the "air", so it's volume decreases.

    By the way, I walked into a walk-in refridgerator at work a couple Mondays ago that someone had put several pounds of dry ice into on the previous Friday. The the room was full of "air" but it had about 17% oxygen instead of the 21% my body was expecting. I noticed the taste of the air was odd, and about a minute later, I was feeling a little tight in the chest. I found what I was looking for and left the room, and felt like I was going to pass out about 30 second later. Pretty odd sensation. Good think there was still some oxygen left... At least I now know what being at the top of Everest is like now!
    Kirk

    For up from the ashes, up from the ashes, grow the roses of success!

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