Jobo 2502 Reel Better Than 1501 Reel?

Discussion in 'Darkroom Equipment' started by RedSun, Nov 13, 2012.

  1. RedSun

    RedSun Member

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    Someone mentioned the advantages of 2502 vs 1501 reel before, but I can't find it. Can someone tell me again?
    I believe all can be used in all Jobo processors, small or large.
     
  2. Diapositivo

    Diapositivo Member

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    Somebody says the 25xx series, having a larger diameter, allows for a more uniform development of film. That's because in a tank the inner coils have a different agitation pattern than outer coils. That's, IIRC, the argument.
    I understand the theory but in practice I use only 15xx and cannot detect any problem in uniformity of development.
    15xx series also uses a lower volume of chemicals.

    If you are beginning now buying your tanks starting with 25xx might be a good idea if you lean toward the perfectionist. Perfectionism sometimes is not about actual results but "peace of mind" that you are adopting the best techniques and not "leaving on the table" the last bit of quality.

    If you already have 15xx tanks replacing them with 25xx doesn't make a lot of sense on real practical ground IMO.
     
  3. RedSun

    RedSun Member

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    I see. It makes sense that more chemical goes in between the layers. But it does not make sens in some other ways. The 25xx tanks are larger. The the outer edge of the reels rotate at a faster speed than the inner layers. So the outer layers of film receives faster flow rate of chemicals than the section in the middle. The difference can be large if you load long film, such as 2 rolls of 120. In essence, you get different agitation rates.

    Since the film tanks should be rotated at a lower rate, it should not be a concern on the chemical getting in between the layers. I'm more concerned with the different agitation rate.

    I already have the 1501 reels, so I do not think I'm going to upgrade to 2502 until I hear something different.
     
  4. djhopscotch

    djhopscotch Member

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    Wouldn't that tear the reel apart? :munch:
     
  5. jk0592

    jk0592 Member

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    I use the 15xx series for 120 film without any problems whatsoever, and the larger 25xx for 4x5 only.
     
  6. ic-racer

    ic-racer Member

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    Perhaps, if you used a centrifuge to spin the water off after a run.

    In terms of development:
    I spoke with a Jobo representative back in the late 1990s when I was purchasing my Jobo and there was no claimed benefit of the bigger reels in terms of evenness of development at the edges of 120 film.
     
  7. RedSun

    RedSun Member

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    I think I remember the comment. It was said that if you load a long film (220 or 135-36) into the 1501 reel, then the film goes further inside the reel. Since the tank/reel rotates, you can't put in too much chemical, or you run the danger that the excess chemical can be leaked out of the tank. The 2502 may have a capacity for a longer film. So the film may not go that far inside, so less danger of chemical leak.

    I do not have a 2502 to compare, so this is why I asked in the first place.
     
  8. Diapositivo

    Diapositivo Member

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    No that's what happens in every wheel. At the amusement park you'll be able to experience it by yourself.
    It's the angular speed which is the same.
     
  9. Роберт

    Роберт Member

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    You can load a 2502 reel a bit easier because the radius is larger. Especially when putting 2 120 roll films on one reel. Apart from that the 25xx system is designed for rotary development while the 15xx system normally is used for inverse processing. For the 15xx system in rotary you will have often a problem for the minimum amount of concentrate for each film in the small tank volume. Further the 25xx system you can use for 9x12cm or 4x5" sheet films.
     
  10. RedSun

    RedSun Member

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    Yes, that was the comment on the amount of chemicals used per sq inch. I'm not sure if that makes any difference. The smaller reels are used in many systems, including the hand processing tanks.