How long can stop bath and hypo last if stored in a sealed bottle with no air leaks?

Discussion in 'B&W: Film, Paper, Chemistry' started by Sirius Glass, Jan 1, 2018.

  1. Sirius Glass

    Sirius Glass Subscriber

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    We know that developers even it sealed tightly still can oxidize and have a finite shelf life. For example, Kodak lists mixed XTOL in a sealed container as having a six months shelf life.

    How long can stock solution stop bath with indicator last if stored in a sealed bottle with no air leaks? Six months? A year? Longer? Is it still good as long as the indicator is still yellow? How can it be tested?

    How long can stock solution hypo [eg. Kodak Hypo, Rapid Hypo, TF4, TF5] last if stored in a sealed bottle with no air leaks? Six months? A year? Longer? How can it be tested?
     
  2. RattyMouse

    RattyMouse Member

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    pH paper would let you know if a stop bath was still worth using. If it's acidic then it can do the job intended.

    I would think that a stop bath would last years.
     
  3. MattKing

    MattKing Subscriber

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  4. Truzi

    Truzi Member

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    I think I'd mentioned in another thread about containers that I had stop in a PET bottle for at least 5 years until it finally started leaking. The bottle was about half-full and I never tried to purge the air. It was indicator stop, and mixing a bit with some developer made it change color - not that it is a definitive test.

    I had Ilford Rapid Fix last a year before eating a plastic bottle. Clip tests were fine until the end, but again, not a great test.
     
  5. OP
    OP
    Sirius Glass

    Sirius Glass Subscriber

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  6. mshchem

    mshchem Member

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    Hypo reminds me of the good old days. I've never called fixer Hypo, maybe it's time to start :smile: I have had fixer go bad (ppt. out sulfur) . I don't push capacity. I make my own paper fix. Kodak Rapid Fix for film. I usually toss indicator stop before it turns purple.
     
  7. George Nova Scotia

    George Nova Scotia Subscriber

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    I've had citric acid based stop bath (Ilford) go cloudy with a growth of some sort (bacteria, fungus) within a couple months. Still yellow but a cloudy mass floating in it. Guess it all depends on what's floating by in the air or water when mixed or used. Stop bath is pretty much a one time use for me.
     
  8. Larry the sailor

    Larry the sailor Subscriber

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    I'm using a bottle of Kodak Indicator Stop that I bought in early 1995. It got put away for a few decades but still seams to work just fine. Still smells just like the stuff in the new bottle I have.
     
  9. Neal

    Neal Subscriber

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    A recurring question. I find that my chemicals last far longer than I need and I usually replace them just because it makes me feel better. A 5 liter package of Xtol is only about 30-35 rolls of 35mm film (for me anyway). RA-4 chemicals seem to go off more quickly. I use a "Silver Magnet" (sold by one of the members here) on fixer and I only toss that after a couple of times through the silver removal process because I get nervous and it makes me feel better. Once the silver is removed film still clears in less than 30 seconds. Many years ago I had a bottle of store brand fixer (concentrate) end up with some yellowish precipitate when it was down to the last quart. Last fall I found a bottle of Clearfix at the back of the cabinet that was mixed (for prints) at least 3 years ago when I needed to use a community darkroom for a bit. Film cleared quickly so I used for a few proof printing sessions. Eco-Pro paper developer goes off faster than Dektol but I find that adding a bit of concentrate on occasion brings back the blacks without problem. If anyone cares, I always use distilled water and store in PETE gallon jugs that juice comes in.

    I do have one occasional issue. Once in a while, a dark precipitate will coat the wall of a bottle of well used fixer. When it happens, I put the fixer through a de-silvering and put it away until my next trip to the household chemical recycling center. If anyone knows how I can avoid this it would be great.
     
  10. paul ron

    paul ron Subscriber

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    ive never had any issues with stop going bad. i had a jug of it tucked in the back of my cabinet i discovered when cleaning. the date on the jug was 2001, and it looked in perfect condition. i dip sticked it for ph and it was as good as the day it was made.

    fixer, kodak 2 part, goes bad in less than a month. it percipitates white crud.

    dont use a hypo for fixer... hahahahaha
     
  11. Steve Goldstein

    Steve Goldstein Subscriber

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    Once I had a >six-month-old working-strength batch of Kodak Indicator Stop Bath start growing something. PE suggested adding 1 gm/liter of Benzooic acid to prevent this.
     
  12. Europan

    Europan Member

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    I shouldn’t keep a stop bath. On the contrary I deem it must be fresh every time. I use water with a shot of an acid, with the reversal process where I bleach with sulfuric acid to bring pH down the stop bath gets the same acid. On negatives I use acetic acid, sometimes boric acid because that acid does not disrupt the fixing bath. After the fix I want the fixing chemicals to become destroyed and soluble, so citric or glacial acid goes in the first wash water. Here formic acid would be best because it evaporates without a trace but it’s too expensive.

    A bath keeps well for months when stored in glass bottle(s), air sealed with vaseline. Take care to not let vaseline come in contact with the bath. Siphon effect and hose.
     
  13. trendland

    trendland Member

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    Well - thats indeed interisting - bugs often decided about the shell life of stop bath.
    With used final wash bath (several destilled water steps) it is quite clear
    that bugs make it unusable after weeks/month.
    But in a such acid enviroment - bugs may also feel fine ?....:unsure:
    But unused acid based stop should be usable for years - I never need to give it away.
    with regards
     
  14. darkroommike

    darkroommike Subscriber

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    Stop bath stock solutions will last for years, both citric acid and acetic acid are used as preservative I don't worry about the working solutions, since my usual session will just about always "use up" the acid in my tray. I have had both Kodak and Ilford rapid fixer stock go off and precipitate, I now try to buy in smaller quantities. Powdered fixer will last almost forever, mixed fixer I would discard in six months.
     
  15. WilmarcoImaging

    WilmarcoImaging Member

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    I am using a "years old" bottle of stop bath and it works as new. Yellow color, pungent acetic odor, neutralizes developer instantly as detected by fingertips.

    I was a gifted a "years and years old" bottle of stop bath which was mixed to 28% from glacial acetic. It is pungent and I expect it would work as new.

    I don't see a limit to the useful life of stop bath at 28% or glacial concentrations, except for evaporation. I use it one shot and mix on demand/as needed.
     
  16. R.Gould

    R.Gould Member

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    I buy fixer in 5 liter containers, and keep the fixer in those containers until used, at least 2 years, sometimes 3, and have yet to have it go bad, I use either Champion Amfix or Tetenal superfix, with indicator stopbath, last 1 liter bottle lasted 18months to 2 years, and no sign of going bad, with mixed stop I use until indicator changes color, with fix diluted I follow a simple rule 8 films then discard, for prints, useing 2 bath method I use the second fresh bath twice, then swap it to the first,used bath and mix fresh for first bath, I normally make between 8 and 10 prints in a session, fixing test.home made, shows that this method works fine
    Richard
     
  17. MattKing

    MattKing Subscriber

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    One thing that makes the question slightly confusing is the question: "What constitutes a stock solution?"
    For liquid chemicals, I take that to mean the solution as it comes from the manufacturer, no matter how concentrated that might be.
    In addition, in some cases questions of longevity may be more about the containers than their contents.
     
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