Kodak Hardening Fixer Usage

Discussion in 'Black and White' started by cenelsonfoto, Feb 10, 2005.

  1. Hello.

    New at developing, so far so good, did second roll this afternoon. I
    have a question about fixing:

    I use Kodak fixer which I purchased in powder form - I bag to a
    gallon of water. Not a lot of instructions on the bag, really
    nothing more than "mix this way" and "dont be an idiot and drink
    this stuff". I am using it full strength, works fine - can I pour
    the fixer back into the main stock and reuse? So far I have been
    dumping it, and at this rate fixer will be expensive. I have a gut
    feeling that I should be reusing it until it is exhausted yes?

    Thanks in advance, O Sage Ones.

  2. You can extend the life of your fixer by using the two-step process.

    The link is here.

    Look on page 3, bottom right.

    - Randy
  3. Not using working bottles for chemistry is asking for a fatal work stoppage, usually at 1am Sunday, when an entire lot of something is contaminated. Used solutions are more easily monitored if kept segregated.
  4. You can pour it back, but that's not the best way to go. Mix up the gallon and separate it into smaller bottles and use them sequentially. You can reuse the fixer until it nears exhaustion.
  5. I hear ya, Stu. I actually have smaller working bottles, will halve my main stocks tomorrow and begin working from smaller bottles. I feel like a moron for tossing nearly 40 ounces of fixer....

    Thanks, guys.
  6. Dear Craig,

    Kodak suggests that film should be fixed for twice as long as it takes to clear, and that Kodak Fixer (powder) should be used for no more than 10 minutes. Therefore, if you check your film at 5 minutes and it hasn't cleared, you need new fixer. They also say that 1gal of Kodak fixer will fix 100 rolls of film, but I've never shot 100 rolls of film in the 2 months time limit.<g> http://www.kodak.com/global/en/professional/support/techPubs/e103cf/e103cf.pdf?id=
    Rather than use the powdered fixer that has to be mixed all at once, I use Kodafix/Polymax Fixer (a liquid) and keep a quart mixed at all times. After a couple of months, I mix a new quart. It works for me.

    BTW: I use non hardening rapid fixer for prints so that quart only has to support film development.

    Neal Wydra
  7. You may already know this but I'll put it up for those who can use it. To test your used fixer the easy way, soak a piece of exposed, UNdeveloped (junk) film in water for 30 seconds, then put it in the fixer with agitation. Note the time it takes for the film to become clear. Fixing time for your good film is at least twice the clearing time you noted in your test. Discard the fixer when clearing time exceeds 60 seconds. Save 35mm leader tongues for test pieces. Kodak fixer has a good use capacity before it's shot.
  8. Glen's suggestion is good. I do the same thing. Sixty seconds for rapid fixer is about right, but for the standard sodium thiosulfate stuff you're using, it's more like 3 minutes.
  9. The actual rule for clearing time tests is to note the clearing time with fresh fixer, and consider the fixer exhausted when the same film takes twice as long to clear. And there's no need to presoak the film for the test.

    Note that some films (like T-Max) will take longer to clear, while others (notably the microfilms I use in my Minolta 16 cameras) will clear very quickly -- so you need to test clearing with the same film stock every time to get usable results. But there's no set number of seconds, it's when the clearing time has doubled from fresh that the fixer is exhausted. With the film-strength Ilford Rapid Fixer that I use, clearing time for a Tri-X leader started out at around one minute, and after processing a couple dozen rolls in the same two liters of fixer, is now up to around a minute and a half (even though the fixer has been mixed and in its juice jug for almost six months).

    Expiration and everything else takes a back seat to film clearing -- that's testing the actual function of the fixer. If you don't do clearing tests, then follow the labeling concerning both capacity (typically 24 rolls per liter of film) and expiration (normally shown as 60 days from dilution or mixing).

    Oh, and CE, some people *do* one-shot their fixer, but most of them dilute it significantly from the working solution you have mixed -- I've used Ilford Rapid Fixer at 1:24 from concentrate, which is 1/5 the recommended film strength, and it still fully fixes film in under ten minutes, with plenty of reserve capacity; it's tempting to retry that experiment (using it in a monobath made from commercial developer and fixer) with half the amount of fixer to see if that would improve shadow detail by further slowing the fixing.
  10. Thanks for that 1/5 Dilution of fix idea, will have to play around with that idea.
  11. FYI:
    We make a powder fixer (sodium thiosulfate---HYPO) that will clear film in twenty seconds or less. CP POWDER FIXER askus@claytonchem.com
  12. I'm actually pondering the use of a highly diluted (1:9 or 10% of normal) first fixer bath after 5x 1 minute water rinses, then followed by one or two full strength fixers baths for two reasons:

    1. Reduce the sudden shock of going from a highly alkaline fixer to an acid fixer since that is reputed to cause grain clumping and possibly causing other negative effects on the emulsion.

    2. Reduce the risk of potassium entering the second fixer (especially when using Rodinal).

    I'm also plan to try the Formulary's Archival Fixer, again using the above technique but largely becaue of reason 2 since it precludes the shift from alkaline to acid environment (unles you have acid rainwater for a rinse).

    Does anyone have any input on this method?
  13. RH- I think you're thinking about the right stuff, and I've had similar thoughts about "the shock of...", but I can't say any of it matters in terms of results. Kodak powdered fixer works just fine with every material I've used, and so does TF-4. No difference in grain or anything else. I wouldn't dilute the fixer- it's designed to work best at the dilution specified, which for Kodak powdered fixer, is straight up. I keep three bottles. One is the gallon stock solution. The second is a 1 quart bottle for reusing paper fixer. The third is a 16 oz bottle for reusing film fixer. The 16 oz bottle is a plastic soda bottle, and I mark the number of usages on the side with a permanent marker. When capacity is reached, I start a new row of marks on the next ridge.
  14. The Formulary's TF-4 is an ALKALINE fixer, thus there would be no pH shock to begin with. Starting with a highly diluted ACID fix, which aqll of the remaining options are, would I suspect reduce the creation of any heat (which is at least part of the cause behind the "shock" effects) when using the acid fixers.

    The other issue according to the "Cookbook" is depletion of the active sodium fixer by conversion to the inactive potassium salt as a result of contamination by potassium bromide or iodide, with the KBr a very significant issue with Rodinal. Thus a rinse in a dilute
    acid fixer would tend to diminish this consequence at the same time you are gradually LOWERING the pH. This would help to conserve the remaining 2 full strength acid fixer baths.

    I have in the past used Rapid Fixers without the hardners but now intend to try TF-4 using the fixer conservation methods I've mentioned (although the pH issue is not inherent with TF-4).
  15. I should also note that developers using "carbonate" buffers are particularly prone to film damage when placed into acid baths due to the creation of carbon dioxide bubbles within the emulsion. This is the reason water rinses are highly recommended with many high acutance developers such as those based on Crawley's FX developers, including Photographer's Formulary's TFX-2. I have no doubt that misunderstandings of this has resulted in catastrophic issues with film treated in acid stop baths and acid fixers.
  16. There are several urban legends here:

    1. There is no thermal shock when going from an alkaline developer into an acidic solution. The high specific heat of water and the low chemical concentration buffers the film from any severe shock. The material presented in A&T was more as a hypothesis or a theory than presented as fact. I have verified this with EK experts and also with Bill Troop. It is an excellent idea, but has not been able to be proven by anyone.

    2. Modern films are not affected by CO2 bubbles formed when going from a carbonate developer to an acid stop or fix. The hardeners in the film itself prevent that. Now, I speak only of film from the major manufacturers such as EK, Agfa, Ilford and Fuji.

    It is true however, that swell is pH dependant. Swell is lower at pH 4.5 and climbs stadily as pH goes up to about 9 or 10. As swell increases, film and paper both become more sensitive to scratches and abrasion. Therefore, you have to be more careful with your processed wet materials if you use no stop and an alkaline fix.

    It is true that an acid fix, used for long times can dissolve or etch fine detail in silver images, so you have to be careful. It is also true that too much alkali used too long can begin to degrade gelatin. Both of these effects only occur in extreme cases, not in normal use. They are normally of no concern at all if you practice common sense in your darkroom.

    Ron Mowrey

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