Black and white film--reversal processing question

Discussion in 'B&W: Film, Paper, Chemistry' started by S.Frank, Jan 22, 2014.

  1. S.Frank

    S.Frank Member

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    I recently processed two rolls of Tmax 100 with a reversal kit from photographer's formulary, with less than optimal results. The film has an irregular splotchiness, sometimes looking like splatter. In some cases the top and bottom edges of the frames are darker in tone, like a stain. I did a continuous agitation with my bleaching step; I wonder if I need to do a better wash afterwards or perhaps a more rigorous agitation regime with the clearing bath solution.
    Any thoughts?
    Thanks

    --Sean
     
  2. Alessandro Serrao

    Alessandro Serrao Member

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    Maybe you should consider a chemical fogging
     
  3. johnielvis

    johnielvis Member

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    could be anything. Maybe not enough rinse after the development--residual developer reacting with the bleach to make it less active. Could be stuff in the water you used to mix it causing problems. Could be not enough solution in the tank--did you fill it to cover the film with all solutions? You can pull it out after the bleach step and check if it's ok or not before the clearing bath and do the clearing bath by inspection--this will also serve to give you the light re-exposure. Something mixed wrong? maybe post a color pic of a strip of the film?
     
  4. cliveh

    cliveh Subscriber

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    How did you reverse the image?
     
  5. S.Frank

    S.Frank Member

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    reversal

    Everything was done by the book--proper volumes of chemistry,temp accuracy. Re-exposure was done with a 150 watt bulb. I suspect the problem is either in the washing or clearing bath, so I will do these more thoroughly with my next two rolls and post the results.

    Thanks for the input

    Sean
     
  6. jochen

    jochen Member

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    Hello,
    I suggest that the bleaching bath is of the permanganate/sulfuric acid type. I read somewhere that this chemistry is not as reliable as the former dichromate/sulfuric acid type which is toxic and carcinogenic. It seems to make more problems.
     
  7. Gerald C Koch

    Gerald C Koch Member

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    The permanganate bleach can be less reliable since if the pH becomes alkaline manganese dioxide will precipitate. If this happens in a region of the film you will get a brown to black stain. The permanganate bleach can also cause softening of the emulsion. The dichromate bleach causes less problems and is safe if one is careful. Before disposing of the dichromate bleach add a bit of sodium sulfite to it. The color will change from orange to green showing that the chromium has been reduced to the less problematic Cr (III).
     
    Last edited by a moderator: Jan 25, 2014
  8. Alessandro Serrao

    Alessandro Serrao Member

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    I stand by my previous post: to me it's a light fogging issue. If the film is taken out of the reel, or it's on the reel but taken out of the tank (that is out of the water) the water droplets that form on the film itself cause that issue. A chemical fogging has many benefits: it will yield maximum DMax, it's reliable, it's more practical.
    It would be useful to see some scans.
     
  9. Gerald C Koch

    Gerald C Koch Member

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    Since light fogging is done to completion the presence of water droplets on the film during the process would have no effect.

    A simple fogging developer is sodium sulfide which produces sepia images.
     
  10. Alessandro Serrao

    Alessandro Serrao Member

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    Lemme disagree on this: a chemical fogging redeveloper is much more potent than light reversal. The Ag+1 are ALL reduced to Ag0, contrary to what happens in a light reversal exposure, where practically not all silver granules are exposed and then reduced by the following developer (as happens in the negative process).
    Infact all light-reversed and redeveloped methods call for a fixer at later stages, contrary to what happens when a sulfide fogging is used.

    I suggest the OP to use Super Iron Out as a fogging redeveloper.
     
  11. Gerald C Koch

    Gerald C Koch Member

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    I think that the difference in density produced by the two methods would be very small if it existed at all. An interesting experiment for anyone with access to a densitometer.