Bleaching print for toning and lith-redeveloping

Discussion in 'B&W: Film, Paper, Chemistry' started by wilfbiffherb, Oct 22, 2012.

  1. wilfbiffherb

    wilfbiffherb Member

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    hi all,

    once again i must call upon your collected wisdom to get me out of a fix. i was doing my first lith prints this weekend and decided to try out some bleach redeveloping. i was using fotospeed ld20 and some bleach from a speedibrews chestnut toner.

    i have two problems with 2 prints.

    first - i printed/dev/stop/fixed normally and put the print into the bleach. it was at this point i realised i didnt know how much to bleach. do i bleach until theres nothing left on the print or do i just bleach until the print looks flat and grey? after a while i put the print back into the lith and the print that resulted had very swirly patterns on it.

    second - again i printed/stopped/fixed as usual, bleached the print and washed it then put it into the toner. the print just kept getting lighter and no toning occurred.

    not really sure whats going on. I dont really know about bleaching. Does anyone have any bleaching tips/pointers on what bleach to get hold of?
     
  2. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    1. When you do 'second pass lith' as Tim Rudman calls it, you start with a print that has been printed about 1/2 stop too dark. The reason for this is that if you start with one that is perfect, bleach back, and redevelop fully, the print will look pretty much the same as the original. To get the crazy colors and the interesting effects, you must stop before the print is fully redeveloped, hence the 1/2 stop over-exposure in the enlarger required when you make the original silver gelatin print.

    2. For second pass lith you bleach the print back as far as you can, almost to paper white.

    3. For toning, it's a matter of preference how far you bleach back. The farther you bleach back, the stronger the toning will affect the print.

    4. For toning - try diluting the bleach like 1:50 from the stock solution, and get your bleach from the same source every time so that you don't have variations in the results, making it a guessing game how much to bleach.
     
  3. wilfbiffherb

    wilfbiffherb Member

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    I thought about getting some of the fotospeed variable lith bleach as it is the only one i have found where you can buy the bleach seperately form the toner. what bleach do you recommend?
     
  4. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    Most bleach products are potassium ferricyanide together with bromide. The ferri bleaches the image, and the bromide rehalogenizes the print so that it's sensitive to redevelopment again.

    The most common is for people to mix their own. I have found, however, that when I purchase Moersch toners I get way more bleach than I need, so I have never needed to mix my own...

    - Thomas
     
  5. wilfbiffherb

    wilfbiffherb Member

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    i see. ill look into moersch and maybe this fotospeed stuff.
     
  6. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    And, if you can get hold of it (it isn't easy because it involves sulfuric acid if I remember correctly), try some copper sulfate bleach. It makes for some really interesting results. I think you can get it from Photographers' Formulary, but you have to sign some sort of form to be able to buy it.
     
  7. paul_c5x4

    paul_c5x4 Subscriber

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    Copper bleach
    Copper sulphate 5g
    Sulphuric acid 30% (battery acid) 2ml
    Sodium chloride 5g
    Water to make 100ml

    Always add acid to water.

    I've just come across another formula that uses acetic acid in place of sulphuric - If I get time this week, I might just try it.. By far the easiest bleach to make & use is the potassium ferricyanide & potassium bromide mix. 5-10g of each in 100ml of water (ratio & quantities can be varied), and dilute by up to 1+9.

    The pot.ferri/bromide ingredients are available from Silverprint in the UK and are quite safe to post. Sulphuric acid is not so easy to find unless you have a specialist battery supplier close by (Halfords won't sell the stuff). You could also find it in a hardware store sold as drain cleaner (Back Swan is one brand of 97% sulphuric acid :pinch:)