How far can I dilute Dektol?

Discussion in 'B&W: Film, Paper, Chemistry' started by tkamiya, Mar 11, 2013.

  1. tkamiya

    tkamiya Member

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    I am going to make a big print tonight - 16x20.

    I typically dilute Dektol per Kodak's instructions - 1:2. How far can I dilute this and still get a max black? Since I am going to make ONLY ONE print, I'd rather not prepare a gallon of developer using the standard dilution.

    I'd appreciate if you can stick to the topic. Please - no discussion of how dilutions are expressed or if this is a false economy.
     
  2. Kevin Kehler

    Kevin Kehler Member

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    I think the worry you need to have is there enough developer in the tray to react properly - if you put 1oz of developer in 1 gallon of water and left it for a month, it would never turn completely black. How much developer solution do you need to cover 16x20? I personally wouldn't go more than 1:4 or 1:5 and still obtain an acceptable print - of course, a longer develop time will be required.
     
    Last edited by a moderator: Mar 11, 2013
  3. MattKing

    MattKing Subscriber

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    Dektol has a capacity of thirty-two 8 x 10 sheets per litre of working strength solution. So each litre of normally diluted (1:2) working strength developer has enough chemical capacity to develop eight 16 x 20 sheets.

    So theoretically you could mix up a litre of 1:2 solution, and then dilute it further so as to end up eventually with effectively a 1:8 solution, and still have enough capacity to develop eight 16 x 20 sheets.

    I would try a test. Most likely you will be doing some test strips anyways. Try developing a smaller strip in some 1:8 developer. You will probably need something like 8 minutes developing time - maybe longer.
     
  4. tkamiya

    tkamiya Member

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    I guess I'll have to try this myself. I was hoping someone has done this already.
     
  5. MattKing

    MattKing Subscriber

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    FWIW, I do use Polymax-T at 1+14 rather than the recommended 1 + 9 when I do 11 x 14 and larger, and with a 33% increase in standard developing time (90 - 120 seconds, RC paper) everything works well.
     
  6. Rick A

    Rick A Subscriber

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    You could theoretically use one liter at standard dilution if you processed in a drum, or a trough, instead of a tray. I used to use a canoe shaped tray to save chems for color prints, would work for B&W as well.
     
  7. MattKing

    MattKing Subscriber

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    A flat bottom tray with 2 litres of chemistry would probably work if you are diligent and careful.

    And you could probably use a slightly more dilute version of Dektol (1 + 3 or 1 + 4?) at the same time.
     
  8. tkamiya

    tkamiya Member

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    Holy cow! DRUM! I forgot I have one! Thanks. That solves my problem.
     
  9. Bill Burk

    Bill Burk Subscriber

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    Hi tkamiya,

    I recently had just 8 ounces of Dektol left and wanted a print. So I diluted 1:5 and developed for 6 minutes.

    Both prints same batch of Galerie 3 and same roll of 35mm film (so black border would match). Both lightly Selenium toned.

    The difference could be attributed to two differences I see: greater dilution - or the greater net exposure on the denser print.

    Black Border Density: 1.58
    Base exp: f/11 32 seconds

    The previous print done normally in Dektol 1:2 for 3 minutes:

    Black Border Density: 1.88
    Base exp: f/8 25 seconds
     
  10. Gerald C Koch

    Gerald C Koch Member

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    I read an article in one of the major photography magazines many years ago about using a sponge to put the developer on the print. From the example they gave the technique worked rather well.
     
  11. George Collier

    George Collier Member

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    Or use something for a trough of some kind, like wallpaper glue thingies, you can get at local building supply. A lot less chem, just see saw the print back and forth. You might be able to use your normal dilution with just a bit more time. Test a strip and compare to a small tray developed print that has the blacks and contrast you want.
     
  12. PhotoJim

    PhotoJim Member

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    Other options to diluting:

    1. Buy the one-litre pack.
    2. Buy the ingredients to make D-72 (very similar to Dektol) from scratch, and then you can mix up precisely what you want and no more.
    3. Mix a bull fatch and use it up. Print another shot too, or make contact sheets or other prints.

    The stock solution will keep for a few months. You can mix up the 3.8-litre pack, and only use part of it. Dilute the portion you need to do your prints, and save the rest for another batch of developing in a week or two or ten.
     
  13. tkamiya

    tkamiya Member

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    He, he, he..... spell checker strikes again!
     
  14. tkamiya

    tkamiya Member

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    Yes, Jim, I can mix my own D-72.... I have been doing that, actually. Sadly, at the quantity I purchase, it costs me more than double of buying a gallon bag of Dektol.

    But that really isn't the problem. I just wanted to make ONE print with minimum of stock solution. I'm going to try this tomorrow. I got side tracked today.
     
  15. Michael R 1974

    Michael R 1974 Subscriber

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    tkamiya. The drum option might be your best bet.

    Richard Henry did fairly extensive densitometric testing of Dektol at various dilutions, development times with factorial development etc. At dilutions greater than 1+2 dmax began to fall off even with increased development time and there was increasing compression of all densities > approx 1.5. Further, development times greater than 8 minutes tended to cause fogging problems. Granted, these tests were with Ilfobrom in the 80s, but still probably directionally useful.
     
  16. Athiril

    Athiril Subscriber

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    It depends on the paper you're using, many have a developer built in, which simply on it's own can develop to a deep grey, which just needs a little extra developer to get to full dMax.
     
  17. tkamiya

    tkamiya Member

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    It's an Adorama store brand RC paper. I have no idea who actually manufacturers these paper....

    I'm going to try drum for the first time.
     
  18. NedL

    NedL Subscriber

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    I use Adorama store brand a lot and my normal dilution for dektol is 1:4. I used to use 1:2, 2 minutes and could never see much difference between 1:30 and 2:00. Now with 1:4 I usually go about 2:15, but I can't see much difference after 2:00. I use a method similar to single tray, except it's "single container".
     
  19. PhotoJim

    PhotoJim Member

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    Nice typo I did there :smile:
     
  20. NedL

    NedL Subscriber

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    My bull fatch didn't last.
     
  21. tkamiya

    tkamiya Member

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    I ended up catching flu/cold and I am bored, tired, and unable to concentrate at the same time. I so much want to print!!!
     
  22. NedL

    NedL Subscriber

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    Bummer. I hope you feel better soon. I too have learned to stay out of the darkroom when I'm tired and unable to concentrate.
     
  23. Kilgallb

    Kilgallb Subscriber

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    I learned to stay out when I have had a few. Don't ask.