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  1. #11

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    Quote Originally Posted by Mike Wilde View Post
    It is possible to watch by pulling the lid of the tank and lifting the reels after the film has been in the bleach in incandescant a few minutes, provided you use a stop and a rinse after the developer. Do rinse before using this bleach, because there are no pH buffers with just kFerri kBr.

    When doing bleach time visually I would bleach for a minute after I could no longer see an image, and treated it like fixer; when it takes twice as long to bleach then when new, consider it time to start a new batch.
    Mike, I have done C41 but what was happening in the tank was always a mystery. I realise that bleach is to bleach away the silver halides, leaving the colour dyes only but when you say "no longer see an image" does this mean that there is nothing there after successful bleaching? Isn't there a colour image which requires fixing.

    Can you clear up my confusion. Thanks

    pentaxuser

  2. #12
    Mike Wilde's Avatar
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    Sorry about that- what I mean is that the dense image turns a bit into a 'ghost' - it is not transparent until the halogenated silver is removed in the next step - the fixer.
    my real name, imagine that.

  3. #13

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    Thanks for that Mike. I wonder if someone like me who hasn't seen the ghost effect would be able to tell when it had got to the right ghost condition on which you add the 1 minute and also use as the formula for exhaustion? The bleach formula you have given seems simple to make, relatively cheap and most important the chemicals are easily obtainable in the U.K. so it is well worth a try provided I can do the assessment but correctly.

    pentaxuser

  4. #14
    Mike Wilde's Avatar
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    Sorry for the lack of more empirical information on the time to bleach/ability to bleach to exhaustion.

    A trial could be to test - shoot a roll of grey card or macbeth card, and snip off a few frames and process them.

    See what the film looks like after 1:00, 1:30, 2:00, 2:30, 3:00, 4:00 in a fresh batch.

    Go and then see when you consider there is no visible change in the bleaching action, and make that your 'fresh' minimum fix time.

    If you want to get numerical, go and process a bunch of strips that you can tell apart (scratches in emulsion prior to processing, etc) and pull them off the reel and into a running water bath after the above sequence time in the bleach when their time is up.

    Then fix all at once, and measure the optical effect of the final negatives with different fixing time with a densitometer, or the time to print a grey square in RA-4 if doing the tests optically.
    my real name, imagine that.

  5. #15
    Mike Wilde's Avatar
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    Spinning - say 4 seconds in 30 seconds. I spin left and let it spin 2 seconds. Then I spin right and let it come to a stop. YMMV.
    my real name, imagine that.

  6. #16
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    Quote Originally Posted by little-infinity View Post
    I know C-41 chemistry goes bad fast....
    Many people seem to "know" that. It's because it's mostly an internet legend. Well of course it's true if you compare to Rodinal, but otherwise..... I think that color chemistry keeps quite well! (Especially RA-4 but that's a different story.)

    I've never had C-41 chemistry go bad. I store them in squeezed PET bottles without air. 6 months is normal, just like with most BW developers. I've had XTOL die much more quickly than any color developer.

    But of course, to be on the safe side, better to follow the manufacturer's conservative figures. They usually talk about 6 weeks.

    Blix didn't go bad too quickly, either, when I used it. But again, separate bleach + fix is more dependable also in terms of shelf life.

    Displacing all the air is the key. Reducing temperature also helps considerably, but don't go too low. I have found no problems storing in a fridge at 4 deg.C so I could suggest it as a personal experiance, but follow the manufacturer's guidelines here (not below 10 deg.C) just to be sure.

  7. #17

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    Many people seem to "know" that. It's because it's mostly an internet legend.
    Actually that's what I was told by one of the technicians that works in the photography area of our school when I inquired why they did not allow C-41 to be processed there, only B/W. I also was told that the chemistry is extremely toxic. Guess that's bogus too?

    So much for learning anything at school *rolleyes*

    In anycase I might be moving on to the Formulary Kit (Kodak Flexicolour that is repackaged in a 1L kit).

    Would those accordion bottles be any good? I don't have access to nitrogen or any of that special aerating stuff, so I need a quick home-made way to keep air out. I can store in my fridge.

  8. #18
    Mike Wilde's Avatar
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    Look into 'Private Preserve' for storing opened wine and scotch bottles, to displace air off the top of chemistry. Nitrogen and argon I recall. The last one I bought was $20, and lasted me for a few years of processing when I started with colour. It came from a cigar store next to the Vintages LCBO outlet in the Sherwood Village shopping centre.

    I have a healthy sized surplus stock of labware glass bottles free to you to get you started. Get in touch.

    Don't waste your money on the accordion bottles; they are not viable compared to plain old glass, even with good old marbles used to mimimise air space.
    my real name, imagine that.

  9. #19
    hrst's Avatar
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    Quote Originally Posted by little-infinity View Post
    I also was told that the chemistry is extremely toxic. Guess that's bogus too?
    Yes, that's a legend too. Color chemistry can be even less toxic than many B/W developers due to nonexistence of metol and hydroquinone. Instead, there is a phenylene diamine derivative color developing agent that can be allergenic (similarly to hair dyes), but nothing really toxic. Bleach and fixers are very innocent, and final rinse does not include even trace amount of formaldehyde anymore.

    These legends are so well-spread that most instructors who haven't acquired the correct information by themselves, are just uninformed but have heard the legends... And it's not always easy to questionize all you hear! Well, all we can do is spread the information.

    Luckily, when in doubt, using common sense helps quite a bit as a starting point. Color processing is/was done on a HUGE scale commercially in minilabs everywhere, so the process must be designed so that it cannot be very toxic to workers or environment. Otherwise it would have been caused HUGE concerns.

    Would those accordion bottles be any good? I don't have access to nitrogen or any of that special aerating stuff, so I need a quick home-made way to keep air out. I can store in my fridge.
    Accordion bottles are mostly useless. You cannot displace all the air from them easily, which is just against the whole purpose of them. But, I find that plastic (PET) soda bottles work fine and are easily squeezable.

  10. #20

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    Yeah, even friends of mine who were enrolled in the well-respected local university's fine arts photography program were led down that path of misinformation. They were pretty incredulous and amused that I was intending on doing C-41 processing in my kitchen. I haven't heard anything from them about it since I was successful.

    Is it not true that E-6 was in part (or in whole?) developed as a process that could be "more easily" done at home?

    And I second the recommendation for soda bottles. Cheapest and easiest source of flexible PETE bottles.

    I myself am wondering about using products like Dust-Off canned air to displace oxygen. I've searched before, but never found much that was definitively said about it.

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