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Thread: Determining PRINT fixing time.

  1. #11

    Join Date
    Jun 2013
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    Re: Determining PRINT fixing time.

    So, as far as I know there is no way to accurately determine fixing time for prints.
    See there (same page as mentioned by ic-racer) about halfway down,
    https://unblinkingeye.com/Articles/A.../archival.html
    the frame about "Testing for Residual Silver After Fixing". If you go that way, do not store the sodium sulfide anywhere near photo paper or film.

  2. #12

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    Re: Determining PRINT fixing time.

    Quote Originally Posted by Bernard_L View Post
    See there (same page as mentioned by ic-racer) about halfway down,
    https://unblinkingeye.com/Articles/A.../archival.html
    the frame about "Testing for Residual Silver After Fixing". If you go that way, do not store the sodium sulfide anywhere near photo paper or film.
    Yes... I guess that the page mentioned by you and by ic-racer contains really good advice. What I find remarkable from that is that an efficient fixing is key. In the two bath, the first bath removes almost all salts from paper, and the fresh second bath ensures a perfect fixing without extending time...

    To me this is the key: without extending time A priority is not alowing fixer penetrating much in the base !

    Well, this is for our loved FB, because RC has not that problem...

  3. #13

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    Re: Determining PRINT fixing time.

    True, determining fixing times and capacities for prints is not as cut-and-dried as with film.

    That said, there are a couple of standard, best practices for determining both that has been discussed at length here and over on Photrio (former APUG). I'll summarize here:

    First, there's a difference in approach if you're using RC or fiber-base paper. For the former, a one-bath fixing regime with full fixing times and a good determination of fixer capacity will do the job very well. "Archival" processing is less of an issue with RC paper since the fixer does not soak into the paper base like it does with fiber base paper. Fixing RC paper is a lot like fixing film.

    Whatever method you end up deciding on for your workflow, it will require that you determine a throughput capacity (with a sufficient safety margin) for your fixer and paper combination. This has largely been done for you by the manufacturers, so if you don't want to do a lot of testing, trust these recommendations. If you do want to test your workflow (like me), then you need to test your workflow for residual silver using either the ST-1 test (the one mentioned above from Photographers' Formulary) or by using the selenium toner test (which I'll detail below).

    Secondly, if you are using fiber-base paper and interested in archival or optimum permanence, and don't want to spend a lot of time (and money) replacing your fixer every 10 prints or so, two-bath fixing is (really!) the way to go.

    So, step one, decide on your method. For RC one-bath fixing is fine. For fiber-base paper, you'll need to decide a couple of things. Be aware that manufacturers' recommendations for fixing capacities for fiber-base paper are usually based on a less-than-optimum standard of "general-purpose" or "commercial" use. For this, a capacity of 35-40 8x10-inch prints per liter and a one-bath fixing regime is normal. If you are not interested in processing to "archival" or "optimum permanence" standards, this may be fine for you. If, on the other hand, you plan on exhibiting and selling your prints, you may want to consider more thorough processing.


    If you want optimum permanence, a one-bath regime will get you a throughput capacity of about 10 8x10-inch prints per liter of working-strength fixer before the fixer needs replacing. Yes, this is really low, but after about 10 8x10s through a liter, the dissolved silver content in the fixer is high enough to prevent optimum fixation (read the Ilford tech sheet on their fixers carefully if you want to confirm this).

    The cheaper and, IM-HO, more convenient and secure method is two-bath fixing. In this regime, you mix two fixing bath and divide the maximum recommended fixing time between the two fixers. The first bath will then have the capacity of the one-bath method above, i.e., 35-40 8x10s per liter and is where the bulk of the fixing occurs; the second bath then finishes off the mostly-fixed prints, bringing them to "optimum-permanence" standards. When the capacity of the first bath has been reached, it should be discarded and can be replaced by the (still really fresh) second bath. A new second bath is then mixed. According to Kodak, you can repeat this cycle 6-7 times before mixing both baths anew.

    Shortcut: The easy way to get optimum permanence for your fiber-base prints is to use two-bath fixing and the manufacturers' recommended throughput capacity.

    Ilford vs. Kodak approaches to archival fixing: Kodak bases their recommendations on years and years of (older) research and testing. They recommend a weaker fixer for fixing prints (i.e., "print-strength") and commensurately longer fixing and washing times. Ilford more recently found that a stronger fixer solution ("film-strength") and a shorter fixing time can prevent the fixer from absorbing all the way into the paper base of fiber-base papers. This can then allow shorter fixing and wash times. You need to inform yourself about the pros and cons of both methods and choose the one that fits your workflow. The Ilford sequence for optimum permanence is available from them as a tech sheet - just Google. Basically, you fix fiber-base prints for one minute in "film-strength" fixer, wash in water for 5 minutes, treat in wash aid for 10 minutes and give a short final wash. The Kodak regime comprises longer times, a treatment in HCA and then a longer final wash.

    FWIW, my preference is for the longer Kodak regime. I find it difficult to divide a 60-sec. fixing time between two baths, especially with larger prints and longer drain times (a 16x20 print needs a 15 sec. drain time...). I use Ilford Rapid Fixer or Hypam at the 1+9 dilution ("paper strength") at 1.5-2 minutes per bath, a treatment in wash-aid and a minimum 60-minute wash.

    Testing for residual silver:

    If you want to be really sure that your regime is doing the job of archival processing, you need to test for residual silver after the final wash. The most thorough way to do this is to push your regime past the point of fixer exhaustion to find the point where your regime fails and then scale back 30% or so of capacity to build in an adequate safety margin. I've done this for my workflow, but it's really time consuming. Better, I think now, is to use the manufacturers' recommendations and then test the last print through for residual silver (and for residual hypo to test your washing!). If this tests okay and you are not using inordinate amounts of chemicals, you should be good to go. If you really need to squeeze every last bit of capacity out of your fixer for whatever reason, then you'll have to do a lot of testing different batches at progressively larger capacities till you find the failing point. Not worth the time or expense IM-HO.

    At any rate, here are the tests for residual silver from the horse's (Kodak's) mouth:

    Kodak® Residual Silver Test Solution ST-1
    Distilled Water 125 ml
    Sodium Sulfide (anhydrous) 2 g
    (This solution keeps for 3 months in a small tightly-sealed bottle.)
    To use, dilute 1 part of the above stock solution with 9 parts distilled water. This working solution keeps less than a week. Squeegee your print or film and place one drop of the working solution on a border area. Let it sit for 3 minutes and blot with a clean cloth or tissue. Any discoloration other than a barely-visible cream tint indicates that your print or film still contains silver halides that require further fixing to remove.
    [Information taken from Processing Chemicals and Formulas for Black-and-White Photography, Kodak Publication No. J-1, Eastman Kodak Company, 1973.]

    Using Kodak Rapid Selenium Toner as a Residual-Silver Test
    Kodak Rapid Selenium Toner 1+9 with water (according to Tech Pub. J-1, 1973, p.41.)
    1. Place a drop of the diluted solution on a squeegeed, white margin of a print or a clear part of film.
    2. Wait two to three minutes; then wipe off the drop with a clean blotter or cloth. Any discoloration other than a slight cream tint indicates the presence of silver. Refix.

    Note on the above: Using undiluted KRST may be better. see http://www.apug.org/forums/forum37/8...er-test-2.html .

    Hope all this helps somewhat.

    Doremus

  4. #14

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    Re: Determining PRINT fixing time.

    Doremus, this a very good summary, I save it for reference.

  5. #15

    Join Date
    Jun 2013
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    89

    Re: Determining PRINT fixing time.

    Same as Pere Casals. Thank you for the information (documented, traceable) and for taking the time to write it up.

  6. #16

    Re: Determining PRINT fixing time.

    Great discussion. But I am curious, what about the claim on photographers formulary that TF5 needs no hypo clear? I’m pretty sure I read a post from Photo Engineer somewhere in the forums recently (1-2 months) that this was the case.

    What say you?
    Last edited by scheinfluger_77; 1-Dec-2018 at 12:54. Reason: I hate spell check
    --- Steve from Missouri ---

  7. #17
    Arca-Swiss
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    Re: Determining PRINT fixing time.

    One other point-If you use an acid stop bath the first bath or your only fixing bath will last much longer before depletion. The PH is opposite in developer from that of fixer and therefore will oxidise the fixer much faster with the residual developer on the print dragged into the fixer, even with a water bath. Use any indicator stop bath at about 1/2 strength as it can veil a print slightly and cause you to lose sparkle in the highlights of your prints.
    Rod Klukas
    US Representative
    Arca-Swiss International
    480-755-3364


    Digital Camera Solutions including R-series Technical Cameras, Large Format View Cameras and Ballheads. 480-755-3364

  8. #18

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    Re: Determining PRINT fixing time.

    Quote Originally Posted by Rod Klukas View Post
    One other point-If you use an acid stop bath the first bath or your only fixing bath will last much longer before depletion. The PH is opposite in developer from that of fixer and therefore will oxidise the fixer much faster with the residual developer on the print dragged into the fixer, even with a water bath. Use any indicator stop bath at about 1/2 strength as it can veil a print slightly and cause you to lose sparkle in the highlights of your prints.
    Rod, let me add to your comment that also there is an alternative if using water stop bath, from Ilford Rapid Fixed datasheet, page 3:

    Adjusting fixer pH
    If a stop bath is not used and the pH of the fixer
    bath is found to be to high when measured, i.e.
    more alkali than it should be, then a few drops of
    a 50% acetic acid solution may be added to
    lower the pH value. This addition should be done
    gradually and with thorough stirring. Do not lower
    the pH of the fixer bath too far, the limits are given
    above.

  9. #19

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    Re: Determining PRINT fixing time.

    Thank you everyone for taking the time to post your responses.

    Special thanks to Doremus Scudder for the excellent summation, very informative.
    Also special thanks to Pere Casals for your response.

    Everyone's contribution has provided us with a intelligent discussion on this topic.

    Bravo!
    "People take different roads seeking fulfillment and happiness. Just because they're not on your road doesn't mean they've gotten lost." - H. Jackson Brown

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