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  1. #1
    2F/2F's Avatar
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    C-41 Bleach Test

    Hello,

    Can anyone describe a way to determine if a gallon of C-41 bleach that has been sitting for some time (probably over a year and a half) is still any good? I believe I had used about half the capacity of 120 rolls 135 format before I capped it and stowed it last. I know Kodak lists the shelf life as "indefinite", but I still would like to know if there is some sort of leader test or other sort of test that I can do. I also have a bottle that is well over two and a half years old, but I know this one is near the end of its capacity, having gone through two sets of the other chemicals using the same bottle of bleach.

    Thanks in advance.
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

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    David Lyga's Avatar
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    Bleach test

    First, you do not HAVE to bleach after fixation. That does nothing to 'preserve' the film/paper from bad stuff. In fact, Hollywood has on occasion refrained from bleaching prints in order to provide a subtler, less garrish color. The colors are more muted this way. I process both film and paper with fixation, first, then I visually inspect (roomlight OK after fixation). If the negs look underexposed (flat) sometimes I do not bleach as that slightly reduces contrast further. But getting to your question about how to tell effectiveness of the bleach: process film or paper as I said: through fixation, then take a portion of the film/paper and put it into the bleach. If after a few minutes you do not see a 'line of demarcation' signifying bleaching action, the bleach is bad (unusual unless contaminated). Remember: paper bleaches MUCH more readily than film, so the film test is best. - David Lyga.

  3. #3
    Photo Engineer's Avatar
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    A more definitive test would be to develop (in the light) and fix a normal piece of B&W film or color film in a good strong B&W developer. I would then wash and dry normally and set aside several pieces for tests such as this.

    Ok, now, the test is to just dunk in a strip of the above film, using the questionable bleach using the time and temperature specified for that product. Then rinse and fix and wash. At this point, with good bleach, the B&W test strip should be completely clear, or the color test strip should have the normal color negative dmin. This indicates the complete removal of silver.

    PE

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    2F/2F's Avatar
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    Thanks, PE. Sounds like a good use for that expired, questionably stored, low-end (Target/Imation), 24 exp. 35mm color neg film I was given some time ago.

    So, how does this sound: Pull the film out of the cassette and fully expose it, put it on a reel, develop in HC-110 dil. B for five minutes, then fix for five minutes in b/w fixer, wash and dry? When it comes out of the bleach after 6:30 at 100F, all I should see should be orange mask?
    2F/2F

    "Truth and love are my law and worship. Form and conscience are my manifestation and guide. Nature and peace are my shelter and companions. Order is my attitude. Beauty and perfection are my attack."

    - Rob Tyner (1944 - 1991)

  5. #5
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    You have to wash, fix and wash as well to see the orange mask. Otherwise you see the residual silver halides which darken the image and can fool you.

    I used to use this test at Kodak to test a new bleach or blix formula for a rapid test. I had everything reduced to times at 20C so I did not have to heat things up. If you wish, that 20 deg C test is valid if you go to the trouble of calibrating it first regarding bleach fix and wash times.

    PE

  6. #6
    Wishy's Avatar
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    A question on bleach life.

    How many rolls should I expect to be able to do using 1l of dilute bleach solution before it becomes "questionable"?. Fuji hunt include very little information on this, but there is a massive increase in economy if i start to reuse my bleach and buy just the developer.

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    Quote Originally Posted by Wishy View Post
    A question on bleach life.

    How many rolls should I expect to be able to do using 1l of dilute bleach solution before it becomes "questionable"?. Fuji hunt include very little information on this, but there is a massive increase in economy if i start to reuse my bleach and buy just the developer.
    There should be a replenishment rate on the bleach, that can tell you how much volume you need for one roll of film. Then just take 1 Liter divide by this amount and it will give you an approximate life.

    Also, keep your eye out for closed photo labs - once they close, you have a good chance of getting chemistry cheap!

  8. #8
    Wishy's Avatar
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    No such luck with the fuji kit. They provide values to extend development time over reuse (Which I'd rather avoid for the sake of 50p a film in chemicals). I'm guessing they expect the bleach and fix to be dumped when you finish with the developer

  9. #9
    Mike Wilde's Avatar
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    Usually bleach life from Kodak can be found in the Z manual's. I presume that Fuji's is something close to the same capacity. It can be judged visually. Time the bleaching by turning the lights on/lid off the tank after a minute in the bleach. Then look how the bleaching progresses when fresh. When times extend to twice that of fresh you are likely close to it pooping out. Bleach can be brought back by some degree by aeration.
    my real name, imagine that.

  10. #10

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    There's also a bleach regenerator product by Kodak, I have used to regenerate C41 bleach.



 

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