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  1. #1

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    Black and white film--reversal processing question

    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. #2

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    Quote Originally Posted by S.Frank View Post
    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
    Maybe you should consider a chemical fogging

  3. #3
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    How did you reverse the image?

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

    Francis Bacon

  4. #4

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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

  5. #5

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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.

  6. #6

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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 Gerald C Koch; 01-25-2014 at 02:49 PM. Click to view previous post history.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

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  7. #7

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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.

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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.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

  9. #9

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    Quote Originally Posted by Gerald C Koch View Post
    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.
    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.

  10. #10

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    Lemme disagree on this: a chemical fogging redeveloper is much more potent than light reversal
    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.
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery



 

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