Pink stain on the back of Azo prints

Discussion in 'B&W: Film, Paper, Chemistry' started by GregW, Mar 15, 2013.

  1. GregW

    GregW Member

    Messages:
    225
    Joined:
    Dec 10, 2012
    Location:
    East Coast
    Shooter:
    Multi Format
    I'm contact printing some 6 x 10 negs from my Kodak VP 3 on expired azo. The paper is really nice and doesn't have any fog, edge yellowing etc. Great contrast btw. I'm using super fix 1:9, Foma stop and Foma paper developer. Anyway, some of the prints have faint pink cloud stains on the back? Nothing on the front? Any ideas on what is causing this?
     
  2. kevs

    kevs Member

    Messages:
    544
    Joined:
    Aug 21, 2006
    Shooter:
    Medium Format
    Could it be stains from retained developer, not neutralised in the stop bath, reacting with the fixer? If so, you might need to a) use a stronger stop bath b) make sure your stop bath is fresh c) increase the time the print spends in the stop bath d) drain the print of developer before putting into the stop bath.

    Alternatively, you could be picking up chemical contamination on the backs of the prints from somewhere. I think selenium toner leaves pink stains IIRC.

    If you're drying prints flat on screens or otherwise, water can accumulate in dips and cause staining as it dries. Perhaps moisture is remaining trapped behind the prints as they dry face-up and marking the back. Some older-style papers are really vulnerable to these problems; I had tons of fun with water pools on dead matt Multigrade IVFB; it took me ages to work out why it was staining - that was on the emulsion but it's possible the same thing is happening to your prints.

    Just a few suggestions, and probably miles out. :-D

    Cheers,
    kevs
     
  3. GregW

    GregW Member

    Messages:
    225
    Joined:
    Dec 10, 2012
    Location:
    East Coast
    Shooter:
    Multi Format
    Thanks Kevs, It's appearing right out of the fix and I am sometimes a little to hurried when i print. I think your first suggestion is on the money, I bet i'm not leaving it in the stop long enough. I'll try and be more careful in the future, as you say, they are temperamental but when it works it really works! Thanks for the help!