Weston Diploma question

Discussion in 'Alternative Processes' started by deisenlord, Sep 17, 2007.

  1. deisenlord

    deisenlord Member

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    I've been using Weston Diploma and notice when my Potox is hotter than 120 degree is looks like it defeats the sizing in the sheet and completely saturates its. I haven't noticed any adverse effects other than the final dried surface may loose some of its smoothness and it doesn't dry as flat. Are there going to be any other long term adverse archival effects of this? Should I avoid this? I like very warm images so like my developer hot.
    Thanks,
    Ike
     
  2. wilsonneal

    wilsonneal Member

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    This is what I noticed as well, and ultimately it's why I stopped using it.
    n
     
  3. Robert Hall

    Robert Hall Subscriber

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    Same here.
     
  4. clay

    clay Subscriber

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    I use this paper for workshops because it is so forgiving. But the last thing I want is newbies slopping around hot developer, so I always use cold-bath developer, which will give you very nearly the same warmth as hot pot-ox even though you keep it in a tray at room temperature. The only downside to this developer is that it gets murky and black a lot more quickly than regular pot-ox, so I end up tossing it sooner. But if you make your own developer from potassium carbonate and oxalic acid, all you need in addition to make cold bath is some potassium phosphate monobasic. The cool temperature of the developer will keep your sizing from being fried.
     
  5. deisenlord

    deisenlord Member

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    Perfect Clay, will give this a try!
    Ike
     
  6. deisenlord

    deisenlord Member

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    Do you have a formula for the cold bath ?
     
  7. clay

    clay Subscriber

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    I will look this up tonight and confirm, but I am pretty sure that it is :

    150g potassium oxalate
    75g potassium phosphate monobasic
    and water to make 1 liter of developer

    Normally I just mix up all my potassium oxlate developer from scratch, so i have a lot of it in a gallon jug. Its nominal composition is 250g of potassium oxalate per liter. 150/250 = .6, so I add 600ml of regular pot-ox (already mixed) 75g of the potassium phosphate monobasic and then top off to 1 liter of solution.

    Will double check all this tonight at the house.

     
    Last edited by a moderator: Sep 17, 2007
  8. clay

    clay Subscriber

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    I was off slightly. I have edited the formula with the 'correct' proportions. Although you would be surprised at how insensitive this process is to things like developer dilution.
     
  9. bill schwab

    bill schwab Advertiser Advertiser

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    Thanks for this Clay!
     
  10. eggshell

    eggshell Member

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    Hi Clay,

    Does the PO formula with pot phosphate monobasic change the contrast & printing speed as compared to standard PO?

    Also, what is the formula to mixing my own PO from Potassium Carbon & Oxalic acid? Do they need to be lab grade? I remember a post not too long ago but couldn't seem to find it.

    Thanks a million.
     
  11. clay

    clay Subscriber

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    No, it doesn't have to be lab grade. Here is the recipe from Eric Nielsen on the alt list, which is the one I use:

    2 lbs of Pot Carb with 1.75 lbs to make 1 gallon of water. 1 lbs = 457
    g and 1 gallon = 3.8 l ( top of my head but close enough as it is just POT
    OX).

    Mix your Pot Card into cool distilled water; about 1/2 your total volume.
    SLOWLY add your Ox Acid as it WILL BUBBLE!!!!. Add to completion and top
    off with water to make final volume.

    Do this outside. It releases a lot of carbon dioxide. Not poisonous, but can displace all that nice oxygen filled air your lungs desire.

     
  12. eggshell

    eggshell Member

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    That does it! Thanks again Clay.