p-aminophenol in Rodinal staining negs?

Discussion in 'B&W: Film, Paper, Chemistry' started by fotoobscura, Nov 17, 2008.

  1. fotoobscura

    fotoobscura Subscriber

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    Quick question here.

    After very long stand developments (8h, 1:300) with Rodinal I've noticed a purple cast on the negatives. My only guess that this is the phenol in Rodinal. Out of curiosity I scanned a negative in RGB and the resulting output was a very ethereal extremely subtle blue/purple hue to the grays...

    Thanks
     
  2. df cardwell

    df cardwell Subscriber

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    umm, what kind of film ?
     
  3. fotoobscura

    fotoobscura Subscriber

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    Sorry APX 100, although I'm not sure the film type has to do with the cast.
     
  4. df cardwell

    df cardwell Subscriber

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    because many of today's films have a purple cast regardless of the developer ?
     
  5. Alexander Ghaffari

    Alexander Ghaffari Member

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    35mm APX has a blue-gray cast, while 120 APX has a clear base (120 Rollei Retro has a blue-gray cast because it is cut from 35mm master rolls).

    What color is your Rodinal after development when you pour it out?
     
  6. fotoobscura

    fotoobscura Subscriber

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    Hi Alexander,

    The Rodinal is dark purple.
    Thanks.
     
  7. alanrockwood

    alanrockwood Member

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    I thought that rodinal was a non-staining developer.
     
  8. df cardwell

    df cardwell Subscriber

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    8 hours changes everything
     
  9. fotoobscura

    fotoobscura Subscriber

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    Rodinal doesn't stain in regular development (1:25,50,100) but the sheer length of time sitting idle in the soup may cause this to occur. I've seen this with other long-term developments including yellow-cast negatives using Gigabit film.

    What validated this possibility (which is highly questionable) is that reading the detailed properties of p-anminphenol hcl it indicated the characteristics as "Purplish crystalline platelets."

    FWIW I shot the APX @ 25.

    I actually quite like the cast and so would like to figure it out to accurately reproduce in the future.

    Thanks
     
  10. Alexander Ghaffari

    Alexander Ghaffari Member

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    My Rodinal also turns dark purple when used with APX, although I do not use stand or semi-stand development, so my development times are much shorter than yours.

    Let us know if you find anything out from experimenting, fotoobscura. Thanks.
     
  11. fotoobscura

    fotoobscura Subscriber

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    Ok I mixed that up a bit. Perhaps too many experiments lately. That was in fact Tmax 100 @ 100, stand 8.5HR 1:333 Rodinal

    Enclosing output. A few people I sent this to noticed a purple cast to it but my primary monitor (calibrated, etc) doesn't see it.

    [​IMG]
     
  12. gainer

    gainer Subscriber

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    Although the HCl comes into Rodinal when it is made, it does not survive the contact with KOH or NaOH. The end product is sodium or potassium aminophenolate and KCl or NaCL, not p-aminophenol.HCl. I don't know if this bit of trivia has anything to do with the phenomenon at hand. With 8 hours development in a developer that is almost potable, who knows what might have come in with the water of dilution?
     
  13. gainer

    gainer Subscriber

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    Ah HA! Purple or pink cast on TMX negatives! Try a sulfite bath, or add some sulfite to the diluted developer. Rodinal diluted 1:333 has only about 1/3 gram of sulfite/liter, which is probably not enough to bleach the anti-halation or sensitizing dyes out of the TMX. That is my guess, anyway.
     
  14. fotoobscura

    fotoobscura Subscriber

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    Wow hey Patrick still kickin' around I see...I remember your posts on rec.photo.darkroom (or was that photo.net) way back in the day...Long ago acquaintance of Richard Knoppow who taught me everything I ever needed to know about Kodak :smile:

    How's your Vitamin C level doing these days :smile:

    Anyhow, thanks for the chemistry breakdown.

    So the color output (purple'ish) even on a regular rodinal development is not that p-aminophenol.

    The resulting negatives from such long development come out beautiful, printable, and rich in tone. I cannot easily replicate this tone and richness with short developing. OTOH, I can easily duplicate my efforts by long non-agitated stands (contrary to some thoughts).

    One thing is for sure- any film from tmax to apx to plusx will all stain a light purple if I stand develop them for more than one hour. I suppose all I'm really doing is toning and developing at the same time :smile:

    P.S. I'm using purified water for development which who really knows what it's filtering and not filtering..talk is cheap.

    Thanks Patrick.

     
  15. fotoobscura

    fotoobscura Subscriber

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    Oh that's a good call! I'll throw in some sod. sul in next batch! Lets see 1/3 gr sulfite liter add 5 gr sod sul as a starting point. I've been meaning to tinker with long stand and pulled film (apx 100 @ 12!)
     
  16. p3200TMZ

    p3200TMZ Member

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    I am not a chemist, but my stand method of development is 1 hour in Rodinal 1:100 with times increasing to 2 hours depending what I want from the negatives. I have found the I need to pre-soak and pre-wash my film till the rinse runs clear when dumping the tank before developing. My thought was that the extended development time actually allows the anti-halation layer to stain the negatives. I do not have this trouble with Efke emulsions or Rollei Pan 25, but Rollei Retro was the worst followed by Plus-X.

    Just my 2ยข
     
  17. df cardwell

    df cardwell Subscriber

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    How long have you washed the film after fixing ? Either a 10 minutes in a film washer, or, even better, an overnight soak clears the base for me. But, to be honest, I'm not letting the film stand for 1 to 8 hrs.