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  1. #1

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    Inside Paterson tank

    Hi guys,
    Sorry for my English.
    I use reel agitation and it was very interesting for me what is going on inside Paterson tank. Is agitation effective or not? How bottom layers of developer mix with middle and top layers? Because main task of agitation (except stand approaches of development) is to move exhausted developer away from film and to bring fresh developer to film surface. I have made small experiment:
    1) glass tank (exactly as Paterson tank);
    2) Paterson reels with 120 film (unexposed Across);
    3) water;
    4) small tea leaves (will help us to detect layer mixing).
    We will rotate reels with different ways and different velocity. We will try to choose convenient way for agitation.
    Look at my small report (http://v-and-f.ru/agitaciya-vrashhen...d-iznutri.html).
    I was very surprised to conclude that uniform rotation is a worst way to achieve mixing of layers. And powerful rotation (clockwise/counter clockwise) gives us the best results.
    I think this information will be helpful for somebody.

  2. #2
    AgX
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    Your video confirms what tests on evenly exposed films showed, that with continuous uniform rotation a laminar flow pattern evolves.

    You might do an advanced test and use coloured layers, by "stacking" differently dyed layers of fluid. You would have to do so by inserting the fluids with the reel already inside the beaker.

  3. #3
    Steve Smith's Avatar
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    Quote Originally Posted by AndreyV View Post
    I use reel agitation and it was very interesting for me what is going on inside Paterson tank. Is agitation effective or not?
    If you look at the Paterson instructions it suggests that inversion is the best form of agitation and that the twist stick is used just to dislodge air bubbles just after pouring in the developer.

    http://www.photomemorabilia.co.uk/Pa...ns/System4.pdf


    Steve.

  4. #4

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    Quote Originally Posted by AgX View Post
    Your video confirms what tests on evenly exposed films showed, that with continuous uniform rotation a laminar flow pattern evolves.
    Yes, you absolutely right. During uniform rotation we get the next: speed of reels=speed of liquid => no mixing => looks like stand development
    So uniform rotation is a worst way of agitation.

    You might do an advanced test and use coloured layers, by "stacking" differently dyed layers of fluid. You would have to do so by inserting the fluids with the reel already inside the beaker.
    It's interesting.

  5. #5

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    Quote Originally Posted by Steve Smith View Post
    If you look at the Paterson instructions it suggests that inversion is the best form of agitation and that the twist stick is used just to dislodge air bubbles just after pouring in the developer.
    http://www.photomemorabilia.co.uk/Pa...ns/System4.pdf

    Steve.
    Inversion is good. But I use Paterson tank for E-6 developing and inversion is unacceptable there (blich and fix goes out through Paterson's cover).

  6. #6
    Steve Smith's Avatar
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    Quote Originally Posted by AndreyV View Post
    blich and fix goes out through Paterson's cover.
    So does everything else! I don't think I own a tank which doesn't force me to wash my hands after every inversion.


    Steve.

  7. #7
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    Quote Originally Posted by Steve Smith View Post
    I don't think I own a tank which doesn't force me to wash my hands after every inversion.
    Amen, brother!

    Jonathan

  8. #8

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    Quote Originally Posted by Steve Smith View Post
    So does everything else! I don't think I own a tank which doesn't force me to wash my hands after every inversion.

    Steve.
    I use a 2-reel Paterson (System 4) and the cover is tight. Never any leaks.
    A photo amateur
    Sinar P2/F2/Nikon F100/Bronica ETRSi/GS/Saunders 4550XLG/Jobo CPP2/CPE+/Colorline 7000

  9. #9
    PhotoJim's Avatar
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    Agitate by inversion - and wear latex or nitrile gloves to avoid getting the chemicals on your fingers.
    Jim MacKenzie - Regina, Saskatchewan, Canada

    A bunch of Nikons; Feds, Zorkis and a Kiev; Pentax 67-II (inherited from my deceased father-in-law); Bronica SQ-A; and a nice Shen Hao 4x5 field camera with 3 decent lenses that needs to be taken outside more. Oh, and as of mid-2012, one of those bodies we don't talk about here.

    Favourite film: do I need to pick only one?

  10. #10
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    Quote Originally Posted by RedSun View Post
    I use a 2-reel Paterson (System 4) and the cover is tight. Never any leaks.

    Likewise. I depress the center of the lid as I put it on. This applies a slight negative pressure. I ' ve not needed to wear gloves.
    WYSIWYG - At least that's my goal.

    Portfolio-http://apug.org/forums/portfolios.php?u=25518

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