rehalogenate b.w?

Discussion in 'B&W: Film, Paper, Chemistry' started by steveb533, Aug 23, 2012.

  1. steveb533

    steveb533 Member

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    I have a b.w negative that I really like except the top half is slightly underdeveloped. It looks like maybe another frame was stuck on top it. Can I bleach this and redevelop it? It was developed and fixed.

    Ive been googling rehalogenating bleach formula but dont see the exact proportions of potassium ferracyanide and sodium bromide...does anyone know this also?

    Thanks,

    Steve
     
  2. markbarendt

    markbarendt Subscriber

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    The silver you need to get more density is gone, it was washed away with the fix.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    You can use what is called an Intensifier. There are a few formulas for these in the literature.

    PE
     
  4. Gerald C Koch

    Gerald C Koch Member

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    If slightly underdeveloped your easiest choice is selenium toner. There are directions on the web as to strength usually 1+2 or 1+3. The negative should be fixed properly and washed well. Of all the other intensifiers I believe that only chromium intensifier is archival. Intensifiers are dangerous to use requring very poisonous chemicals like potassium dichromate or mercuric chloride.
     
    Last edited by a moderator: Aug 23, 2012
  5. tkamiya

    tkamiya Member

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    It may be FAR easier and safer to compensate for the problem at the printing time....

    Even though intensification is possible, it would be nearly impossible to do so in the right portion of the film only. Once you mess it up, the result is there forever....
     
  6. pentaxuser

    pentaxuser Subscriber

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    Of course we don't know how bad the top half of Steve's neg is but I have seen examples of intensifiers in books and they do seem to have an effect. If it's a problem across the whole of the top half of the neg, might it be possible to use maskoid as in toning and only intensify the top half?

    As insurance and if the neg contains important material Steve could try to make the best print possible then experiment with an intensifier. He has little to lose and a lot to gain even if it is only knowledge of what is or is not possible.

    pentaxuser