question regarding negative bleaching

Discussion in 'B&W: Film, Paper, Chemistry' started by dennisl, Nov 8, 2007.

  1. dennisl

    dennisl Subscriber

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    I have an 8x10 negative with an overexposed area that I would like to selectively bleach. I have done selective bleaching on prints but never tried it on a negative.

    Have accumulated the materials I need (ferrocyanide, brushes, etc.) and am ready to begin. The negative was originally processed in PMK pyro. My question is: should the negative be re-stained after the bleaching process?

    Any help or suggestions would be greatly appreciated.

    Thanks
     
  2. dancqu

    dancqu Member

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    Not ferro, ferri. Less density? Forget the stain. How about
    using the SLIMT? Use a minute amount of that ferricyanide
    on the print paper after exposure. Spare the negative. Dan
     
  3. eclarke

    eclarke Member

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    Make a mask. I agree with Dan, spare the negative. Bleaching can get out of hand pretty quickly on film...EC
     
  4. Doremus Scudder

    Doremus Scudder Member

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    SLIMTs maybe?

    Dennis,

    I would try other techniques before working on the negative too. I assume you are considering the selective bleaching because the areas in question are too difficult to simply burn in during printing.

    SLIMTs at the printing stage may or may not help you. The effect of highly-dilute ferricyanide bleach before developing the paper is to reduce paper contrast proportionally from the shadows up (i.e. more contrast reduction in the shadows, little in the highlights). This is appropriate for subjects that need highlight separation more than shadow separation (i.e. shadow separation suffers the most) and has somewhat the opposite effect of print flashing.

    If, however, you have just a couple bright areas that you wish to reduce and keep the contrast in the rest of the negative "as is," you could try flashing the paper first and see it that gives enough exposure in the highlights for you. This technique does, however, reduce contrast in the highlight areas a bit.

    That said, I see no reason why you cannot reduce your negative. However, with selective bleaching/reducing "haloing" can be a problem unless the areas to be reduced are surrounded by areas of much less density. A proportional cutting reducer used on the entire negative might reduce the highlights enough and still leave the shadows printable without this problem. There are dilutions of Farmer's Reducer that have this effect. Perhaps a combination of overall reduction and print flashing?

    If you feel you need to deal with only the small areas, then by all means try. Ferricyanide bleach will not remove the pyro stain (in fact, you can bleach all the silver out of a negative with ferri, leaving only the pyro stain image). The danger, as mentioned above, is that the bleach diffuses through the emulsion effecting the areas around the area you are bleaching and can cause a "haloing" of less density around the bleached area. This would end up being a dark ring around the area in the print. If you work carefully and with as dry a negative as possible, you can reduce this effect, or at least limit it. Once done, however, the bleaching cannot be undone.

    Good luck

    Doremus Scudder

    www.DoremusScudder.com
     
  5. gainer

    gainer Subscriber

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    Bleaching with ferri will not remove the pyro stain.
     
  6. dennisl

    dennisl Subscriber

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    Thanks to all for the information and advice (and spelling lesson). Sounds like some great suggestions. I think I will try the bleaching but first on a negative I have no intention of printing.

    Thanks again,
    dennisl