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  1. #1
    Athiril's Avatar
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    E6 Bleach Bypass?

    Just wondering if a bleach bypass can be obtained by running the bleach step after reversal and before colour development, then only fixing after (or a partial bleach) like b&w reversals?

  2. #2
    Mike Wilde's Avatar
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    Think about what you are saying in relationship to what each step does. The steps are not magic.

    The bleach uses it's iron's free electrons (free to the silver, which has a stronger affinity to those electrons than the iron three to iron two step does) to take elemental silver that the developers have acted on and thus remove elemental silver, and return it to it's halogenated state, which the fixer then usually removes.

    If you even just partial bleach prior to colour developer, you will be taking part of the image that the colour developer normally would not be acting on (since the first develoiper has already reduced it to elemental silver) and making it a halogen again which would then be fair game for the colour developer to reduce, in adition to the halogens that have been exposed (either optically or chemically) in the reversal step.
    my real name, imagine that.

  3. #3
    Athiril's Avatar
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    If I mimic the b&w reversal process, I dont see why it should be any different.

    Though perhaps I got the order wrong.
    http://en.wikipedia.org/wiki/Reversa...lack_and_white

  4. #4
    Ian Grant's Avatar
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    The B&W process uses a bleach before the 2nd Developer to remove the processed silver, converting it to a very soluble silver salt. This doesn't affect the unexposed so undeveloped part of the film, which is chemically fogged and developed with a colour developer.

    So even if you did remove the first part of the processed silver you'd still need to bleach the redeveloped secondary image as that contains silver as well as the colour dyes formed during the color development stage.

    Ian

  5. #5
    hrst's Avatar
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    There are two kind of bleaches; rehalogenating and non-rehalogenating. BW reversal has to use one that removes silver without converting it to halides. Otherwise it wouldn't work. Color processes use bleaches that convert silver to halides that are then removed by the fixer.

  6. #6
    Athiril's Avatar
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    Why would I need to bleach the secondary image? With the first gone, it should be a positive silver image, hence bleach bypass.

    Okay so it should theoretically work with a potassium permanganate bleach? I have 500g of that stuff sitting here

  7. #7
    Ian Grant's Avatar
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    It is a positive silver image, on top of the negative image and very dense

    If you bleached the first developed image (negative). Why would you want a dense positive made \up of both the silver & dye image ?

    Ian

  8. #8
    Photo Engineer's Avatar
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    The E6 and C41 bleaches contain Ammonia and halide. As such they are weak fix baths as well, which destroy part of the image. Use of them will reduce the finest grains to near nothing leaving the heavy deposits as Silver Ammonium Halides for the fixer to remove.

    As such, if these are carried into any developer, they can redevelop. If it is a color developer, you get dyes along with the silver. In E6 then, you run the risk of having a totally black piece of film result. In negative color, you just get an odd effect from retained silver which is the extreme of using a faulty blix on color film.

    The bottom line is that bleach bypass works on color neg but not on color pos. However, use of a B&W pos bleach before color development, with proper clearing bath before color development, you can then run a bleach bypass and get some really strange results. It goes as follows:

    MQ
    wash or clear
    wash if clear used
    Dichromate-sulfuric acid bleach
    wash or clear
    wash if clear used
    reversal expose or reversal bath
    color developer
    wash
    fix
    wash
    stabilzer with formalin (as you omit the pre-bleach here)

    The results here, and only here will be somewhat akin to C41 bleach bypass if it works properly.

    PE

  9. #9
    Athiril's Avatar
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    Thanks for info PE

    I assume I can use a permanganate bleach too? Just a bit wary about dichromate
    Last edited by Athiril; 10-22-2009 at 08:37 PM. Click to view previous post history.

  10. #10
    Photo Engineer's Avatar
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    Yes.

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