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Thread: Jobo 1520

  1. #1

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    Jobo 1520

    Hey guys. I have a Jobo 1520 tank and I want to develop only 1 roll of 35mm in it, do I still fill it up to 485ml or can I use enough to just cover the roll? (about 300ml)

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    Enough to cover the roll is fine (I think 250mL will do it- better check). But, if you do inversion agitation, it will effectively be more vigorous because the developer will move more and probably faster unless you're very gentle. Also, if you're using a very dilute sort of developer, or one that oxidises quickly, it might lose some power faster than usual, but ordinary developers should be fine.

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    I use 500ml in my Jobo 1520, regardless if I develop 1 or 2 rolls of 35mm or 120 films. I use hand agitation (inversion method), I don't use Jobo processor. I mostly use reusable developer (ID11). Never the less, when use one-shot developer, like Rodinal or Perceptol, I again use 500 ml of working solution. Maybe I do waste 250 ml stupidly

    There is another method, that is rolling tank on floor or better in Jobo gadget made for that, and Jobo tells with that method you need only volume of chemiclaals like is needed when use in Jobo processor (260 ml). But, I never tried that "rolling" method, so I don't know how it really works...

    Never had any problems with 35mm films regardless if I develop one or two at same time, and I had problems with overlaping two 120 films, but that was my fault, I didn't properly load films on reel.
    Last edited by haris; 11-16-2007 at 05:17 AM. Click to view previous post history. Reason: Typo...
    Bosnia... You don't have to be crazy to live here, but it helps...
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    Hi guys, first post to the forum here but thought I'd reply to this since I'm considering a 1520 myself and am looking at tank capacities on the Jobo site right now.

    According to them, it takes 250ml to inversion-process 1 reel of 35mm in a 1510 tank and it takes 485ml to inversion-process 2 reels of 35mm in a 1520 tank. So, can we deduce that it takes 250ml, as with a 1510, to do 1 reel in a 1520?

    If using the same volume in the 1520 as in the 1510, then mightn't the film be completely out of the chemical altogether when the tank is inverted or does this matter for that brief period? Leads to another question too: am I right in thinking that the reels are only ever at most half covered during rotary processing since there's a hole in the centre of the tank lids used for that?

    As you might guess, I'm new(-ish) to home developing in general, not just Jobo, having only ever done it when I took a course 11 or 12 years ago. I'm looking at Jobo tanks instead of any others so that I can upgrade to a CP* processor at some stage if I want to and if people stop handing over such outrageous prices for them on the 'Bay! In fact, B&H must have spotted this trend too since I've noticed they put their price on a new CPP-2 (which they probably don't even have) up to $3500!

  5. #5
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    I am not doing 35 mm anymore so I might be a bit off. But a couple of things to consider. The volumes for Jobo tanks are usually posted for rotary processing with the tank horizontal. You must supply enough volume so that the film on the innermost part of the reel is immersed in fluid when the tank rotates. Unless you use a very dilute developer, the volume required should almost always be sufficient to process the roll of film.

    If your tank holds multiple reels, I would consider loading it with empty reels when processing a less than full load just to keep the variables to a minimum. For inversion processing you will need to fill up the tank with fluid anyway so inserting the empty reels will reduce the volume required to fill the tank.
    Jerold Harter MD

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    They give figures for both inversion and rotary processing for the 1500-series tanks. The figures I gave above are what they say to use for inversion. However, I'm a bit confused now looking at the film capacities for Ilford developers. According to the info in Ilford's liquid developers fact sheet, one-shot development works out to use 60ml per 36exp.

    Taking DD-X as an example, they say to dilute it 1+4 for working strength. That would mean 300ml of liquid (60ml dev. + 240ml water) to do 1 film and 600ml to do 2. Jobo, on the other hand, say to use 250ml for 1 film and 485ml for 2. Therefore I would have to assume that 300ml will not fit in a 1510 tank and 600ml will not fit in a 1520. If that assumption is correct, then how is it supposed to work out?

    If you reduce the total volume but bear in mind that you need 60ml of developer for each roll of 36, then surely your working strength dilution changes. On the other hand, if you reduce the total volume and keep the dilution the same, you presumably are not using enough developer.

    Could it be the case that the dilution is not important as long as your film is covered with the volume of liquid stated by the tank manufacturer and that liquid contains the amount of developer stated by the chemical manufacturer?

    Thanks...

  7. #7

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    Well, through my experimenting (aha) I found out, that 300ml (used water to test) is enough liquid to cover one reel sufficiently.. so should I follow dilution requirements and change to 300ml? (was just going for 500ml)

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    I'm even more confused than I was to start with :-/ I've found this same subject discussed in a few other threads but none of them make it any clearer (with everyone seemingly having their own way of doing things).

    Maddermaxx, you say 300ml is enough to cover one reel "sufficiently" but is 250 also enough as Jobo state? Does it take a further 300ml (making 600 altogether) to cover a second reel in the same tank or is 500ml (or even 485 as Jobo state) enough then? More importantly in the context of my particular confusion, will the tank hold 600ml at all?

    So, question for everyone: if you need, as seems to be the case for Ilford DD-X, 60ml of developer to do one film and that developer needs to be diluted 1+4, giving 300ml of solution, then to my way of thinking, you should need 600ml to do 2 films if you are to use the correct amount of developer and keep the dilution the same. What happens if your 2-reel tank will not hold 600ml? Does that mean you can't do 2 films in it? Similarly, what happens if your tank needs more than that to cover the reels? Do these figures vary depending on the combination of developer and tank?

    Seems to me that, unless all developers require the same amount of working solution per film and all tanks hold the same capacity per film (and, as far as I can see, I don't think either of those statements is true) then, depending on the combination of developer and tank, either the amount of raw developer contained in the solution must change or else the dilution must.

    Any help in clarifying this conundrum greatly appreciated!

  9. #9
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    snowblind:

    There are three measurements that are critical:

    1) the capacity of the developer, and
    2) the volume of the tank, and
    3) the dilution you are seeking to use.

    You are correct - it is recommended that at least 60ml of DDX stock be used for each roll of film. You can use more, but most likely you shouldn't use less.

    The volume of diluted developer that you can use in your tank will vary over a range. The smallest amount will be the minimum amount necessary to cover the film, while the largest amount will be the maximum amount that the tank will hold.

    You may find that your tank will hold a bit more than you think, but if you are going to measure it (use water), you should measure it with reels and film installed (as they take up space).

    If it turns out that you cannot put 600 ml of 1 + 4 diluted developer into your tank, and Ilford's figure of 60ml minimum stock developer is also correct, your only choices are:

    a) to develop just one roll at a time, or
    b) to develop two rolls at a stronger dilution than 1 + 4.

    The question then becomes what the effect will be if you use developer at the stronger dilution - say 1 + 3.5 or 1 + 3?

    If the dilution is close to 1 + 4 (say your volume is 540, and your dilution therefore is 1 + 3.5), you probably just need to use slightly shorter times, to get similar results. I don't use DD X myself, so hopefully someone here who does can chime in on that.

    You may also find that the 60ml minimum per roll quoted is very conservative, and that if your total volume is 540ml, 54ml of stock per roll would work just as well. Again, I don't use DD X myself, so hopefully someone here who does can chime in on that.

    I would tend to lean toward using the stronger dilution, rather than smaller quantities of the stock, but that is just me.

    You might also try a pm to Simon Galley here on APUG. He is very helpful, and may very well welcome the opportunity to answer your question about minimum volumes publicly. You should reference this thread in your pm.

    You might also ask a moderator to revise the thread title to "JOBO 1520, 2 rolls, and Ilford DDX". Moderators always want to help and the revised thread title might attract Simon's attention anyways.

    Matt

  10. #10

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    Snowblind,
    The Jobo 1520 tank will only hold 500ml of fluid. Thats why I use it, saves 10ml per load.
    I mix my dev, acording to the manufactures instructions as all the other chemicals. so if a dev calls for 1+4=5 I divide 500 by 5 =100 so end up with 100ml dev + 400ml water for an example.

    If I am developing 1x 35mm film I use half a tank of fluid unless I am useing multi use chemicals for example T max dev which would be made up to 1 litre of working strength chemical and I fill the tank. Have done it this way for a number of years with no problems. By the way the Jobo 1520 tank is the only one I have used that does not leak when inverting during processing.
    Hope this helpful.
    Regards Paul.

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