Fomapan 100 reversal

Discussion in 'B&W: Film, Paper, Chemistry' started by Alessandro Serrao, Dec 14, 2012.

  1. Alessandro Serrao

    Alessandro Serrao Member

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    Hi there,
    I've just finished to reverse a roll of Fomapan 100 (not the R version).
    I've used:
    1) 1°st development: Rollei RPN 60ml concentrate + 240ml H2O
    2) wash
    3) bleaching: 50ml pt. A + 150ml pt. B + 100ml H20
    4) wash
    5) clearing: 300ml
    6) wash
    7) 2°nd exposure
    8) 2° development: same as 1)
    9) wash
    10) fix
    11) wetting agent
    12) h.t.d.

    bleach pt. A is 6g potassium permanganate in 1000ml (distilled water);
    bleach pt. B is 10ml concentrated sulfuric acid 98% in 1000ml (distilled water);
    clearing is 25g sodium (potassium) metabisulfite in 1000ml (distilled water).

    Some considerations:
    a) I've exposed a set of 4 frames at 25,50,100,200 iso. With this procedure only the 25 iso frame is of normal density, slightly on the thin side. Fomapan 100 yields low DMax, judging from the leader. Next step: less development time or higher developer diluition (one inversion every 5 second);
    b) Bleach doesn't damage the emulsion. I've not controlled the other baths' temperature but the first development. No emulsion frilling, no damage whatsoever;
    c) I've NOT used a silver halide solvent;
    d) the base is cristal clear (I've used a pre-wash).
     
    Last edited by a moderator: Dec 14, 2012
  2. Tofek

    Tofek Member

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    How did you achieve to get the crystal clear base, while it's blue when ordinary processed ?
     
  3. Alessandro Serrao

    Alessandro Serrao Member

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    Sorry, I don't know.
    All I know is that I'm using the 17.5 meter bulk rool of Fomapan 100 batch no. 014215-10.
     
    Last edited by a moderator: Dec 16, 2012
  4. polyglot

    polyglot Member

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    Maybe the bleach is killing the blue dye? Does the film from this bulk roll come out blue when you process normally, or is it clear then too?
     
  5. Alessandro Serrao

    Alessandro Serrao Member

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    To my knowledge there's no chemical treatment that can "bleach" a grey or blue colored base into a crystal clear one.
     
  6. NDP_2010

    NDP_2010 Member

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    I have a few questions if you dont mind answering them :tongue:

    How long was your second exposure and what was the light source/distance from the source?

    Ive just done a development trying Hp5+ with the same process (except different developer), and the emulsion is very soft after the permangenate bleach (ie, if you touch it while wet it just wipes off). Is foma emulsion significantly different to hp5+?
     
  7. Alessandro Serrao

    Alessandro Serrao Member

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    I just don't touch anything when it's wet. I don't unspool the film from the reel. I just expose both sides of the reel (a metal one) for 1 minute each at the glow of a 21w compact fluorescent cool white light. Almost at contact with the lamp.
    The softening of the emulsion depends also on the first developer. It's actually the high pH shift that causes damage.
    If you use a more diluited first developer you'll reduce that pH shift. You must also reduce the permanganate content (aim is 0,3g in 300ml) and the acid (I use 150ml of a 1% sulfuric acid solution).
    Important is keeping a relatively low temperature of 18°C (also lower) of the bleach.
    I don't think Fomapan 100 emulsion is more hardened than any Ilford counterpart. The opposite can be true.
     
  8. NDP_2010

    NDP_2010 Member

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    Thanks for the info. Just following up emulsion softening, i have read dichromate bleach does not soften the emulsion compared to permangenate however both use the same sulfuric acid content and thus wouldnt the pH shift be the same?
     
  9. Alessandro Serrao

    Alessandro Serrao Member

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    Manganese in permanganic acid does not soften anything, chrome in chromium acid crosses-link proteins in the emulsion and harden it. The softening is due to the high pH shift in both cases, the latter being "counteracted" by dichromate.
     
  10. NDP_2010

    NDP_2010 Member

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    thanks for the information :D

    another quick question; do you develop your first development as you normally would a negative, or do you add extra time for development?
     
  11. Alessandro Serrao

    Alessandro Serrao Member

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    I'm nailing the development times down using the paper developer Rollei RPN. I use milliliters versus the notation 1+n just because it's more scientific and practical to me.
    The last trial tonight was 40ml Rollei RPN plus 260ml water. All other parameters were left untouched. I agitate like this: 1 inversion every 15 seconds (except the bleach where I use 1 inversion every 5 seconds). The aim is 12 minutes in the first developer. With this configuration the frame exposed at 200 iso is just perfect.
    To get the frame exposed at 100 iso perfect too I guess I've to diluite more or less minutes.
     
  12. Oxleyroad

    Oxleyroad Subscriber

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    My Foma 100 from 35mm bulk rolls has a very faint grey coloured base. My 120 roll film on the other hand has a really really blue base. The Foma 100 120 while processes well for me as reversal, it views and projects poorly because of its base colour.
     
  13. dr5chrome

    dr5chrome Member

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    ..all foma film except fomaR, 200T 35mm & 800T [now discontinued] are poor films for reversal processing - reasons are too long to even post. Use the ILFORD or ROLLEI or ADOX-SILVERMAX films. Time is better spent elsewhere.
     
  14. Tofek

    Tofek Member

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    How does the Foma R100 compare with Adox Silvermax ? Both rich in silver, both on transparent support...
     
  15. Alessandro Serrao

    Alessandro Serrao Member

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    If Adox Silvermax is similar to Apx100 all I can say is that you'll get very good slides using it.
     
  16. Alessandro Serrao

    Alessandro Serrao Member

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    Some samples are available (Fomapan 100 classic). I'm against posting them on the net 'cause looking at a scan is not the proper way to appreciate or criticize a slide.
    Samples are available by traditional mail upon request (for free).
     
    Last edited by a moderator: Dec 26, 2012
  17. Alessandro Serrao

    Alessandro Serrao Member

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    A strange thing happens: around highlights, where there's a strong transition from white to black, there's a slight white halo. Is there anyone that can explain this?