Bleach for B&W reversal

Discussion in 'Black and White' started by nils_eidvall, Feb 9, 2016.

  1. Hello, I plan to develop some kodak 16mm plus-x reversalfilm in my Lomo-tank but I find it impossible to find me some bleach necessary for the processing.
    Developers, fixers and wetting agents are easy to find but the bleach is really hard, were should I look?
    What I plan to use is
    D-76 for first developer
    ? for bleach
    Re-exposure
    D-76 for the second developer
    Kodak rapid fixer as (you know) fixer
    Should I also use the hypo clearing agent and the kodak photo flo as usual?
    I have also heard that the D-19 is suitable for reversal B&W but I dont know why.
    Is there something else I have missed and can any one help me please?
     
  2. Impossible? Bleach for B&W has been around since the 1900s.
    The Kodak publictaion for labs processing B/W reversal can be found here.
    http://www.kodak.com...ssing/H-661.pdf
    Try as I may I could not find anywhere on their website that gives the current formulae for B/W Reversal Processing. The current process uses permanganate bleach. The original formula:

    Kodak R21a Bleach Bath

    Water 750ml
    Potassium Dichromate 50g
    Sulphuric acid (conc) 50ml
    Water to 1 litre
     
  3. If you struggle to get the acid H2SO4 then look for 'battery
    acid'. I don't know about 16mm but for 35mm it calls for 2%
    strength in solution. If battery acid was, say, 25% strength
    and you needed 400ml of solution, then 2% of that should be
    pure H2SO4. That's 8ml. With the battery acid, you need ?
    *0.25 = 8. In this instance it's 32ml battery acid and 368ml
    water
     
  4. Different developers have different characteristics. That one
    probably improves the contrast.
    Fix after to remove any inactive silver halides and use hypo
    as usual at the last step.
    35mm has a clearing step to remove the bleach stain - I use
    sodium metabisulphite, 25g in 1L. Just don't sniff it!
     
  5. Check out Freestyle Photo.
     
  6. for bleach, I Mix up the bleach in 2 parts, 500ml each. keep em separate until time to use. I add them together at same time. it is not real stable but can be used up to 4 times once mixed if used within a few hours of being mixed together. Part A is 500 ml water with 3g of Potassium dichromate and part 2 is the acid, 500ml water with 12.5 grams Sodium Bisulphate. I got the Sodium Bisulphate at a pool supply company as pool acid. slow agitation for 10 minutes. Your leader (when complete) should be clear. if not, you have not bleached enough.
    just an FYI, I use a chemical reversal step and its much easier than re-exposure with a light source. Peter Cater should chime in. he is the one who gave me his recipe for the process and its great.
     
  7. There is a complete reverse kit available from Klaus Wehner in Paderborn, Germany. This kit is without the crappy materials like Potassiumdichromate.
     
  8. And not importable to the U.S.A. If I could mix these kits here I could sell them here.
     
  9. I would say: Take contact with Klaus Wehner. The same for his ATM-W B&W film developer an Agfa Atomal / May & Baker Promicrol type copy. I will (let) make the developer and reversal kit in Ukraine in the near future.
     

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