D-512 compensating developer (Silom Horwitz)

D-512 compensating developer (Silom Horwitz)

  1. michael_r

    michael_r Subscriber

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    Michael R 1974 submitted a new resource:

    D-512 compensating developer (Silom Horwitz) - D-512 compensating developer (Silom Horwitz)

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    Last edited by a moderator: Feb 6, 2016
  2. Rudeofus

    Rudeofus Subscriber

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    I have not tried this one but mixed several other low contrast developers (POTA, Delagi 8) which need similar amounts (1-2 g/l) of Phenidone in solution. Common sources recommend using hot water to start, this is why Calgon + hot tap water is better than DI water which you need to heat separately. I was able to dissolve 50 g/l Phenidone in Propyleneglycol (or supposedly even better: Diethyleneglycol) and use this stock solution to put the required amount of Phenidone into cold water quickly. It's not cheap but worth the effort, and I don't use such a dev on a daily basis anyway.

    For all those who care: low contrast devs give amazing results with night time exposures on Delta 3200 if they include strong highlights. The low contrast aspect of these devs compensates nicely for the usually high contrast of these scenes (which is even more increased by the Scharzschild effect) and thereby in combination creates beautiful and very realistic looking images that can be easily printed with grades 2-4.
     
  3. Ian Grant

    Ian Grant Subscriber

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    Ilford published a Phenidone - Pyrogallol variation of their ID-4 developer formulae in the original 1941 Kendall Phenidone Patent:

    Example 3


    Part A
    Phenidone 0.4 gm.
    Potassium Metabisulphite 12 gm.
    Pyrogallol 12 gm.
    Water to make 1 litre


    Part B
    Sodium carbonate (anhyd.) 75 gm.
    Water to make 1 litre


    To use 1 Part A + 1 Part B
    Similar in use to a Developer containing 4 gms of Metol



    Obviously quite different to D-512 which has a far higher proportion of Phenidone needed for a balanced Super-Additive effect, Pyrogallol was also used in developers as an oxygen scavenger.

    Ian
     
  4. Rudeofus

    Rudeofus Subscriber

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    The biggest difference between ID-4 and D-512 is not so much the different amount of Phenidone but the extra Carbonate that ID-4 adds. That extra Carbonate brings pH way up and likely changes the overall properties of this dev quite a bit. D-512 is very close to POTA ...
     
  5. michael_r

    michael_r Subscriber

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    Indeed it seems to be a more "stabilized" version of POTA. In Anchell/Troop the addition of Pyro, HQ or Catechol are discussed as potential ways of stabilizing the Phenidone enough (by superadditivity) to make POTA easier to use. Even Metol is considered (not sure why but it seems to follow Crawley's thoughts) and also Glycin - presumably for its apparent ability to make other agents more resistant to oxidation. But the suggested formulas in FDC use small amounts of these additional agents, less sulfite and sometimes additional alkali. D-512 seems quite different in its Pyro concentration.

    On the other hand the formulas in FDC are intended primarily for document/microfilms. D-512 is mentioned in Haist in the context of compensating developers for general purpose films, while POTA is discussed in the context of microfilm development.
     
  6. Alan Johnson

    Alan Johnson Subscriber

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    Here is the working solution of H&W Control (microfilm developer):
    Sodium Sulfite......................4.28g
    Hydroquinone.......................0.076g
    Phenidone............................0.52g
    Sodium Carbonate.................2.19g
    Water to...............................1L

    So D-512 does have a much higher concentration of the secondary developer that regenerates Phenidone.
    Perhaps this is to remove more of the oxidized phenidone that would otherwise give a flat image with ordinary film:
    http://www.jackspcs.com/wondphen.htm
     
  7. michael_r

    michael_r Subscriber

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    H&W Control is another one I've always wanted to try with general purpose film (not microfilm) to see if decent speed can be maintained with extreme low contrast.

    Alan, is this the actual formula or an approximation from a patent?

    It would clearly operate at a much higher pH than D-512, and with its lower sulfite content and very small concentration of secondary agent, it resembles the various experimental formulas propsed in FDC as modifications to POTA where the addition of a small amount of a secondary superadditive agent allows for a lower concentration of Phenidone (and less sulfite).

    What I always find funny are formulas in which weight quantities are given with precision to hundredths (or even thousandths!?) of a gram. :laugh:
     
  8. Alan Johnson

    Alan Johnson Subscriber

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    I have only used H&W Control developer with microfilms,by reducing the time even the contrasty Adox CMS 20 could be developed in it.
    The EI obtained is good, but not up to that obtained using the dedicated developers from Spur.For conventional film one could try developing for a long time to see if it would build contrast.
    The formula I gave above derives from that given for 2.1L of working solution here:
    http://www.frugalphotographer.com/info-formulary-general.htm
    The phenidone is easy to dissolve in 70% isopropyl alcohol from a pharmacy.
     
  9. michael_r

    michael_r Subscriber

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    Ah... I should have remembered H&W Control is made as a 132ml concentrate diluted to 2.1L - hence the decimals everywhere when converted to a per-liter basis.

    I'm adding it to my list of things to try. Thanks.
     
  10. Regular Rod

    Regular Rod Member

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    Is the Calgon not there to provide an alkali? How long does the stock solution keep for?

    RR
     
  11. Ian Grant

    Ian Grant Subscriber

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    No Calgon is has no effect on the alkalinity. It's just there to help if you have hard water.

    Ian
     
  12. michael_r

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    As Ian said, the Calgon is in there as a sequestering agent, which is why I think it is safe to omit it if using distilled water. The Sodium Sulfite in this formula provides the alkalinity. As for keeping properties, I wouldn't expect it to keep very well without modifications. This is essentially a Phenidone-Sulfite developer - similar to POTA (with Pyro added to stabilize/regenerate the Phenidone) so I would not expect it to have a shelf life. I'm hoping to try it out this weekend (assuming my Pyro is still workable).
     
  13. Athiril

    Athiril Subscriber

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    Possibly to prevent the terrible highlights you can get with phenidone alone, or phenidone in high amounts.
     
  14. Gerald C Koch

    Gerald C Koch Member

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    Phenidone is unstable in solution. It can be stabilized with the addition of another developing agent. The phenidone is regenerated at the expense of the other developing agent.

    The H&W developer was optimized for use with microfilm. A better choice for general purpose use might be Perfection XR-1.
     
    Last edited by a moderator: Dec 9, 2013