Tea as a replacement for Pyro

Discussion in 'B&W: Film, Paper, Chemistry' started by David A. Goldfarb, Jul 19, 2003.

  1. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,980
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    I think we all know about experiments involving tea and coffee, which have natural tannins as developers, but the latest issue of _Photovision_ (July/August 2003) has a serious proposal for using the naturally occuring pyrogallol in brewed tea as a developing agent, and the results published in the magazine look pretty good. Two formulas are included, one similar to ABC and one a variant on PMK.

    Anyone try them yet?
     
  2. Donald Miller

    Donald Miller Member

    Messages:
    6,242
    Joined:
    Dec 21, 2002
    Shooter:
    Large Format
    David,
    I found the article interesting as well. I have found my results with Pyrocat to be all that I could hope for, at this point. I do agree with you that the results in the article do appear supportive of the benefit of using a readily available material.
     
  3. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,980
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    Another interesting sidenote about that article was that the version of PMK used a sodium metaborate presoak.

    I was wondering about precisely this thing because I once accidentally forgot to add the A solution to a batch of PMK before pouring it into the tank. My normal procedure is for tank development is to mix up the water and B solution (sodium metaborate), then add the A solution (pyro-metol) to the beaker, turn off the lights, open the top of the tank, and pour it all in (because the tank fills slowly through the daylight cap), replacing the lid and proceding normally with the lights on. After recognizing my mistake, I added the A solution to the tank, and everything came out fine, but I wasn't sure this was a good practice.

    Now that I know that a sodium metaborate presoak is not a bad thing, I think I might repeat this "mistake" regularly, because it means I can do everything with the lights on.
     
  4. Loose Gravel

    Loose Gravel Member

    Messages:
    921
    Joined:
    Feb 28, 2003
    Location:
    Santa Barbar
    I do the Kodalk presoak ever time. I put the stock 'B' in half the water and give 2 minutes of this. The I add the stock 'A' with its half of the water and start the clock. This has helped give even results although I use sheet film in a rolling tank.
     
  5. Ole

    Ole Moderator Staff Member Moderator

    Messages:
    9,281
    Joined:
    Sep 9, 2002
    Location:
    Bergen, Norw
    Shooter:
    Large Format
    Reversed divided developer? Now that's a novel idea!
    I did this by accident recently. Results were unconclusive as I develop by inspection: Fogged negatives...
     
  6. Ole

    Ole Moderator Staff Member Moderator

    Messages:
    9,281
    Joined:
    Sep 9, 2002
    Location:
    Bergen, Norw
    Shooter:
    Large Format
    Are you sure the article said that? If tea contained pyrogallol it would be banned, I think. It does, however, contain Gallic acid and lots of other tannins.
     
  7. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,980
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    More specifically, the claim was that gallo-tannic acid is inherent in ordinary green tea, and "upon sustained boiling, some of the gallic acid molecules in the tannin release and some may even change to pyrogallol."

    It's not a very precise description, but the prints look good!
     
  8. Ole

    Ole Moderator Staff Member Moderator

    Messages:
    9,281
    Joined:
    Sep 9, 2002
    Location:
    Bergen, Norw
    Shooter:
    Large Format
    Gallic acid was much used as a developer in the days of the wet plate, so it doesn't surprise me that it works.
    Conversion to pyrogallol should not be necessary, nor do I think you could do that by boiling (but I may be wrong).
     
  9. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,980
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    I suspect you're right, Ole. According to Gordon Hutchings, gallic acid needs to be heated to 210 degrees C. under pressure to drive off carbon dioxide and convert it to pyrogallol. This would require quite a tempest in a teapot.
     
  10. Robert

    Robert Member

    Messages:
    747
    Joined:
    Sep 10, 2002
    Why is it so hard? Doesn't CO2 like to come out of solution?
     
  11. Jorge

    Jorge Inactive

    Messages:
    4,532
    Joined:
    Sep 6, 2002
    Shooter:
    Large Format
    Co2 in gaseous form does tend to elute depending on pH. When it is bound to a benzene molecule you need energy to break the covalent bonds. Thus the heat and pressure.
     
  12. garryl

    garryl Member

    Messages:
    542
    Joined:
    Jul 19, 2003
    Location:
    Fort Worth,
    Shooter:
    35mm
  13. Donald Miller

    Donald Miller Member

    Messages:
    6,242
    Joined:
    Dec 21, 2002
    Shooter:
    Large Format
    The way I had it figured was why buy tea?...drink pyro.
     
  14. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,980
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    Dr. Johnson drank at least a pot a day, so it could also make you into a brilliant curmudgeon.
     
  15. Aggie

    Aggie Member

    Messages:
    4,925
    Joined:
    Jan 1, 2003
    Location:
    So. Utah
    Shooter:
    Multi Format
    ..
     
  16. fhovie

    fhovie Subscriber

    Messages:
    1,247
    Joined:
    Mar 20, 2003
    Location:
    Port Hueneme
    Shooter:
    Large Format
    You mean I could become a curmudgeon without all that bothersome study and practice?? Wow - sounds like you are on to something!
    -Frank
     
  17. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

    Messages:
    17,980
    Joined:
    Sep 7, 2002
    Location:
    Honolulu, Ha
    Shooter:
    Large Format
    Well, the thought was appealing to me in part because I have a tin of green tea that doesn't agree with me, but I'm too cheap to throw it away.
     
  18. jborden

    jborden Member

    Messages:
    3
    Joined:
    Apr 11, 2004
    Shooter:
    Multi Format
    I don't have access to this issue of PV. Would anyone be so kind as to post the formulae for the developers?