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  1. #21
    mts
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    Color stop baths contain sulfite usually as 1-2% bisulfite. The purpose is to prevent staining in the subsequent bleach. Otherwise it's the same stop bath as used for black and white imagery, so you can simply add some sulfite to your Ilfostop. It is good practice to include a stop bath following any color emulsion developer, RA-4, C-41, E-6, etc. with a wash following.

    Once you complete the stop, say a minute or two, then you can process the remainder of your steps including color developer in room light. You should not contaminate the lab's chemistry but notify them that you are cross-processing E-6 to C-41, and that they should expect positive images and not to print the film.

    Re-exposure in room light is about one minute per side of the reel. I re-expose film on stainless reels after a water rinse by holding the reel a foot or so in front of a 150W outdoor flood light that is mounted above my darkroom sink. Rotate the reel around in the light for a minute, then flip it over and rotate the other side and the job is done. It is a lot simpler and just as reliable in my experience as a reversal bath. Chemical reversal mostly facilitates automated processing machines. Obviously if you are going to dry the film following the first developer, stop, and wash then it will be reversed by hanging in room light while drying.

    You might want to cut the film into two pieces after drying and then complete processing one strip with E-6 and send the other to your lab for C-41 finishing. Images of course should be MacBeth charts intermixed with a colorful scene, for example a mixed flower bouquet.
    By denying the facts, any paradox can be sustained--Galileo

  2. #22

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    Thanks for your help. Now it's gonna take 2 weeks for my order of bisulfite to get here. No chance I could in the meantime try out the process without the appropriate stop bath?

    Oh and is it possible to over-expose during second exposure? Can I just hang the film to dry in a room that isn't dark and let it stay there overnight?

  3. #23
    mts
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    Try using sod. sulfite, also in 1-2%. You might find it at a shop that sells wine making supplies and it is also used as a preservative in some meat products, and of course in photo supply shops where it is almost every developer ever formulated.

    In E-6 and C-41 the bleach and fix processes go to completion, as does the reversal step. You cannot overexpose. Think about it; the image detail develops in the first developer to a negative silver image leaving unexposed silver halides in the various color layers according to the amount of light that was received. These remaining halides represent the positive complement to the already-developed image details. Hence, the halides must be exposed completely in order to be processed by the color developer that produces a positive silver image and also couples the emulsions' dye stubs forming the positive dye image. In the bleach and fix the processing removes all the silver image components leaving the positive dye image.

    You will notice that after the first developer there is not much evidence of the negative silver image owing to the opacity of the remaining halide. After reversal exposure and color developer, the film will appear almost black since it contains totally exposed silver negative and positive images as well as the coupled dyes. Once you bleach and fix, the film magically becomes transparent with a finished image, but it won't appear proper until the film has dried. For permanence it is important to go through the stabilizer bath. Modern C41 films contain the stabilizer in the emulsion so your lab may no longer use a formaldehyde containing stabilizer that is the last step in E-6.
    By denying the facts, any paradox can be sustained--Galileo

  4. #24
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    Sorry to rain on your parade, but it has already been mentioned here that C41 and E6 use a different color developer (CD4 vs. CD3). PE has not only explained that the wrong CD will yield poor colors, also the longevity of these colors is greatly diminished. Thread starter has two options to choose from in my opinion:
    • contact Tetenal Poland and see whether they deliver to Estonia. Poland is reasonably close to Estonia so shipping shouldn't be overly expensive
    • start completely home brewing E6. Recipes have been posted by stefan4u under the title chrome brew here on APUG, mts also has some formulas. Getting the chems may be a lot more difficult than getting an E6 kit, though.
    Trying to be the best of whatever I am, even if what I am is no good.

  5. #25

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    PE has also mentioned many times on APUG that the E-6 process requires a stabilizer containing formalin or formaldehyde in order to make the dyes stable, and that this stabilizer is not needed or used in modern C-41 processing. I don't know what will happen if you cross-process E-6 in C-41 chemistry, but when you get the Xpro film back from the lab, you may want to do a 1 or 2 minute wash in a solution containing formalin (don't wash them afterwards or you'll was the formaldehyde out!), then hang the strips to dry before continuing on with your use (mounting for projection?)

    ME Super, aka The Slide Curmudgeon
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  6. #26
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    ME, that formalin stabilizer will most likely be missing in a modern C41 process. But you can do it as final step, and as Tetenal's manuals state, you can do that later in time, i.e. long after the developed film has been returned to you. But what are you going to stabilize? Unstable dyes which have been incorrectly developed with the wrong chemical?
    Trying to be the best of whatever I am, even if what I am is no good.

  7. #27

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    Yeah, I'm aware of both of these issues. Since I'm planning on buying an E6 kit anyway then this process is more of an experiment for me.

  8. #28
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    I think it's a great experiment, I hope you treat us to a peek at it once you've done it.

    Your post is awfully timely too, considering the slide news from Kodak.

  9. #29

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    I just came across this thread searching for something else. Last year a lab processed an E6 film as B&W. I later found a Kodak document - "Printing Color Films Developed as Black and White" dates April1999 document ref: AE-31.

    In this they describe how to re-process to either get a BW negative
    OR
    re-process to get a color negative

    The colour process follows the OP's initial thoughts, which involves Bleaching in either C41 or E6 bleach; then re-exposure to light; then follow a full C-41 process.

    I have just done this with that film, trying colour processing for the first time to try and rescue this film and the negs are hanging up to dry. Look OK. So all you would need to do is get some E6 or C41 Bleach and then dry, re-spool and send the film for standard processing.

  10. #30
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    I've done it, it works, colour on actual E-6 films become much poorer a few years later using C-41 as a colour developer when I checked (about 2 iirc) - even with formaldehyde stabilisation at time of processing.

    The colour yield is good, it is poor when development is unsuitable, I can get great colour on either E-6 films or CD-4 films using CD-3, CD-4 and CD-2 based developers I've mixed, it can take some work to get there, but it's doable. I've gotten great colour out of C-41 films developed in Rodinal, and rehal processed for a colour negative with a green base using E-6 colour developer.

    Stability is a different issue, C-41 films seem to fare better in that regard with the wrong agent, then E-6 films do, from what I could tell anyway.

    Iirc, it took Xtol 1+1 I think it was 1+1 anyway about 40 minutes at 40 celsius to work, otherwise the slides were too dark (as in black), the solvency simply isn't strong enough to clear the highlights and requires massive development to hit full dMax in highlights to reverse it.

    You otherwise would take sodium or potassium thiocyanate and add it to a developer (about ~1g/L) would be good), or sodium thiosulphate (about 10-15g/L) would be good. This will allow you to use more normal times and temperatures.

    I would use Rodinal 1+25 or 1+50, that seems to work well across the different layers from various experiments with colour film.



    All this isn't a substitute for regular colour processing, but good in it's own right.


    Quote Originally Posted by SimonFreeman View Post
    Oh and is it possible to over-expose during second exposure? Can I just hang the film to dry in a room that isn't dark and let it stay there overnight?

    No, not unless you print out the silver, would require to leave it out in harsh sun for a significant amount of time. Leaving it in an enclosed room over night would be fine. You don't need to let it dry before loading it again to continue process.

    You could also use a reversal bath. They're pretty cheap, and can also be made from simple common ingredients if it cannot be bought (Kodak stuff etc).
    Last edited by Athiril; 05-22-2014 at 10:23 PM. Click to view previous post history.

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