Extending fixing times with reduced concentrations...?

Discussion in 'B&W: Film, Paper, Chemistry' started by Dr Croubie, Jun 13, 2013.

  1. Dr Croubie

    Dr Croubie Member

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    So, well, I'm an idiot. I had some pre-mixed fixer (Ilford Rapid-fix), it was a few weeks old and I couldn't remember how many films I'd put through it, so I tipped it out (probably for the best anyway).

    Now, I've just started developing (135-36 APX100 and a 12-shot hand-rolled Rollei Retro 100, 8+750ml rodinal 1-hour stand), mixed up the stop, went to mix up the fresh fixer. Oh crap, i'm out. Well, almost. Probably about 40-50ml left in the bottle.
    So in my Paterson 4 tank I need 700ml to just cover the two rolls. That makes it 40+640ml, a 1+16 ratio, whereas in the past I've used 1+9 for a few rolls before ditching it and making fresh.

    So, questions is, will it be enough? Having re-used fixer in the past, I'm hoping that there's enough active chemicals floating around to fix the bits that need fixing, and by leaving it in longer and agitating more I'll get those chemicals to where they need to be.
    It's 8pm and getting new fixer within 24 hours is out of the question, and developing's already started.
    I'm thinking if I hadn't tipped the old stuff out I probably could have at least topped it up and it (probably) would have been fine (for future reference, is it ok re-using weeks-old fixer and topping up a bit? or does it go bad?)

    Back in high-school, I remember leaving papers in the fixer tray until the end of the class, then we fished them all out and hung them up afterwards with the lights on, so I'm presuming there's no danger of 'over fixing', i'm more concerned about underfixing.
    Maybe if I just leave it overnight I should be fine? Any dangers of over-soaking the films or anything?
     
  2. wildbill

    wildbill Member

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  3. markbarendt

    markbarendt Subscriber

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    I save the leaders I cut off my films when loading them on to the developing tank reels.

    With some tweezers or similar I dunk the leader in the fix I'm about to use and time how long it takes to clear. The rule of thumb is twice that time for the real film, I go longer 3 to 6 times longer. Most of the time it clears for in well under a minute at normal dilution. If I'm over a minute I'm dumping the fix and using new.
     
  4. Gerald C Koch

    Gerald C Koch Member

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    Go out and buy some more fixer and use it at Ilford's recommended dilution. If money is a concern then go to a two bath system.
     
  5. Rudeofus

    Rudeofus Subscriber

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    In case it still matters: with this highly dilute fixer you should be able to fix your film to the point that it won't deteriorate immediately in room light. Make sure you don't leave your negs in direct sunlight or the like before you can refix them with new (and properly mixed) fixer.
     
  6. MattKing

    MattKing Subscriber

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    Put your regular dilution fix in your tank, turn it on its side and use your hands to rotate it continuously for your standard fixing time.

    If you have a rotary agitator, put the tank on it instead. A couple of heavy rubber bands will keep it in place.
     
  7. Dr Croubie

    Dr Croubie Member

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    Thanks, that's probably the way to go.

    I ended up leaving it in the fixer maybe half an hour to be sure, I was thinking I'd leave it in overnight until I read on another thread that extended fixing times can bleach silver from the emulsion (not sure whether it was the Kodak they were talking about, or if my Ilford Rapidfixer does it too). So just to be safe I washed it and hung it up overnight. Nothing seems to have decayed overnight too much.

    When I think about the maths a bit more, 30+320ml is perfectly normal for a single 135-36 roll, so adding in the extra 10+340ml for a 12-shot roll means there might have been just enough actual chemicals in the bath (except that I discovered it wasn't a 12-shot roll when I unwound it, it was actually a full 36-shot but my eos-3 decided to rewind after 12, I even re-loaded it while shooting and tried again, so it must have been too tight or something. Either way, I got 12 shots and 4 feet of blank).
    So with the extra lot of space in there (does fixer fix only the silver, or blank parts too?) it's probably worth re-fixing as you suggest, I'll hope to get some fresh tonight on the way home from (real) work. It's already washed and dried, but i've re-wound it onto a spool and put it in a box until tonight.
    Certainly not something I'd like to make a habit of, but it should get me out of this emergency for now (and I'll buy two bottles this time and have a spare).

    Thanks for the help.
     
  8. Rudeofus

    Rudeofus Subscriber

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    It's not just the amount of chemistry, it's actually quite a bit about their concentration, too. Fixing is not just about dissolving Silver ions, it's a balance between Silver Thiosulfate complex and Silver Halide. See this posting for some details. What this posting also tells us is that Doremus Scudder hasn't had problems with 1+19 diluted fixer so far, but unless you have the materials to test whether your film has been fixed archivally, I'd still suggest you refix when you get a chance to do it.

    When you develop film, the exposed parts are converted to (black) Silver while the unexposed parts remain (translucent) Silver Halide. This remaining Silver Halide would eventually turn black/brown if exposed to light for longer periods, therefore we use fixer to dissolve these Silver Halides and get them out of the film. As you can guess by now, fixer primarily acts on the blank parts on your film, whereas the black parts are mostly unaffected by it.
     
  9. Dr Croubie

    Dr Croubie Member

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    Thanks, that's what I needed to hear (even if it may not have been what I wanted to hear).
    With those 24 unexposed blank-frames on the Rollei Retro probably hogging all the fixer, it probably wasn't fixed the best.
    I managed to sneak out of work early yesterday and buy some more Rapidfixer, I threw the whole lot back in to a 1+4 mix and left it 10-15mins, that should do it.

    Actually, I cut the 24 blank frames off and didn't re-fix them. I think I'll do a bit of an experiment with them, I'll cut one strip and keep it in my neg-strip folder, hang one in my room, and maybe hang one outside in the sun, see how long each of them take to decay or whatever...


    (meanwhile, just scanning them now, at 3200dpi, 100% on a 27" monitor (about A3 print size), I can just start to make out the grain on the Rollei. Me likey Rodinal Stand Dev, some of these shots were definitely worth the effort re-fixing to keep)
     
  10. Doremus Scudder

    Doremus Scudder Member

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    Dr Croubie,

    I'd suggest reading the directions on your fixer. 10-15 minutes for film in a rapid fix 1+4 is WAY too long. You are likely bleaching away some of the image.

    The question of whether fixer works well at weaker dilutions than recommended is one that remains controversial. There is one contributor here that uses fixer one-shot at very weak dilutions. I have used Ilford Rapid Fix at 1+19, i.e., four times more dilute than recommended, for film and have had good results; no problems with the negatives till now. However, Rudeofus has aroused my skepticism about this procedure, and I no longer use it. When I did use it, it was only for small numbers of negatives; I made sure that the amount of stock fixer was more than adequate to fix the negatives, did a clip test to determine fixing time and exceeded that time by a safety margin. I also test for adequate fixing with the ST-1 test. I now try to use no weaker than 1+9 for film, do clip tests and often use the fixer two-bath for film.

    Furthermore, I am an art photographer. I make prints for display. My negatives are not intended to be archival in any sense of the word. I will likely destroy all of them at some point before I die just to ensure that no one else prints them. Therefore, I'm not so interested in optimum permanence for my negatives.

    For prints, it is another matter altogether. I use two-bath fixing, toss my first bath when 75% of capacity is reached and do regular testing for residual silver and hypo to ensure proper processing.

    Fixer is cheap. If you are interested in proper processing for your negatives and are not willing to learn the chemistry behind the entire process (which can be somewhat daunting) and are not prepared to do your own testing for residual silver, I suggest you use your fixer as recommended by the manufacturer. Read and follow the directions as to fixer capacity, lifespan, and fixing time (not 15 minutes!),

    Best,

    Doremus
     
  11. wildbill

    wildbill Member

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    What he said, read the directions. They don't write them based on theories.
     
  12. Rudeofus

    Rudeofus Subscriber

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    This used to be a problem with ancient acidic fixers, but should not be an issue with modern rapid fixers.

    As I said in that previous thread: a properly done fixer test says more than all my calculations and theories combined. My main recommendation is that one either follows manufacturer's instructions or is prepared to test ones fixer setup. These tests are simple, cheap, and easy to use.
     
  13. jnanian

    jnanian Advertiser Advertiser

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    hi doctor c

    buy some fresh fix and mix it up.
    do the leader test that was suggested
    but with the fresh fixer.
    and double the total clear time as recommended.
    chemistry is cheap don't waste your time and efforts you spent developing your film
    on hoping the extremely dilute fixer (at dilutions you don't even know ? )
    will be useful. who knows, it may look like it worked but just barely cleared your film

    if you are broke, you can use table salt in a super saturated solution
    and soak your film in there for a few days
    and it will make them stable for a little while until you can scrape up enough $$
    for fresh fixer ... you might also consider getting some old fashioned hypo ( sodium thiosulfate )
    it might be less expensive to mix your own by the teaspoon / table spoon ..
    http://www.apug.org/forums/forum37/61254-sodium-thiosulfate-fixer-2.html

    have fun !
    ( and good luck ! )

    john
     
  14. Rudeofus

    Rudeofus Subscriber

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    John, if you read his posting carefully, you will find out that he didn't dilute fixer for DOW (deficiency of wallet) reasons but for EBSC (empty bottle, stores closed) reasons. Even dilute fixer can keep negs stable for a while (read Haist's chapters on stabilizers) so there is good reason to think he chose the right venue to resolve his issue.
     
  15. jnanian

    jnanian Advertiser Advertiser

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    hi rudeofus

    many thanks for setting me straight :smile:

    i figured .. you know ...
    just in case he didn't know about table salt
    and just in case the stores wouldn't open for
    a good 48 - 96 hour period and just in case
    well, the OP decided not to use his dilute fix
    ( cause he was spooked by apug do-gooders :smile: !)
    i figured i would give him a mcgyver :smile:
    its probably easier to find a neighbor with
    a can of salt, than a photo store open, if they
    are closed for 4 days, for some random, unforeseen reason :smile:
    oh, this is all contingent that the OP had 48-96 hours to wait
    for his images to appear hopefully stable before
    fushing to an open store to buy fresh fix and
    wipe the sweat off his brow to re-fix+rewash his film :smile:

    i appreciate the reference to haist !

    john