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Thread: Jobo 1520

  1. #11

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    With only 250ml in a 1520 tank, the dev on inversion "leaves" the film completely as it fills the top half of the tank. Presumably enough of the dev clings to the film and continues action for the second or so that the dev leaves the reel. Even if it doesn't then the film is without dev for a very short period every minute presuming the use of Ilford agitation of 4-5 inversions every minute.

    However if the dev doesn't stick to the film then in a long dev cycle of say 15mins the time without dev presumably needs a correction factor needs to be built in.

    Even if the smaller 1 reel 35 mm tank is used then inversion still deprives the bottom of the reel of dev for a time as some dev flows into the cap area.

    I think that it doesn't matter as it does cling to the film and no time correction needs to be built in but does anyone know which it is?

    pentaxuser

  2. #12

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    Thanks for the replies, all.

    MattKing,
    You mention changing the concentration and compensating with the timing. I notice that manufacturers publish time compensation charts for different temperatures and that, through the likes of the "Massive Development Chart", you can adjust timing for different combinations of developer and film but how would you go about adjusting the timing for different concentrations? You use something other than DD-X so does your developer, by happy coincidence, work out to fit your tank perfectly at the stated amount and concentration or did you have to experiment also? Thanks for that contact -- I hope he won't mind a stranger PMing him (which I probably will once I actually get underway and making mistakes with this lark). Not so sure about changing the name of the thread though -- I only mentioned DD-X since I happened to be looking at its fact sheet. Rather, I was (am) hoping to get a clear idea of how any developer might work out.

    Paul,
    You seem to take the other road -- keep the concentration constant and let the amount of dev. vary. As you said, you would use 100ml of dev. if the stated concentration was 1+4 and would use half a tank of same if only doing 1 roll. Therefore you would use 50ml of dev. for 1 roll and 100 for 2 even though (sticking with the DD-X example) the amount stated by the manufacturer might be 60ml for 1 roll and, by deduction, 120ml for 2. Do you have any problems with that approach? Do you find you also need to adjust the timing to compensate for the lower amount of dev. or do you find, as MattKing suggested, that the min. amount stated by the manufacturer is actually on the generous side?

    What worries me about both approaches is how much experimentation is required everytime one tries a new developer? Knowing my (admittedly anal) approach to experimentation, I would end up wasing 10 or 20 test rolls just trying to find the perfect timing.

    Pentaxuser,
    What you said about 250ml in a 1520 was what I expected to be the case. Have you done this and it works OK with the film being uncovered very briefly? I'm hoping so since I don't want to have to use enough chem for 2 films if I only want to process 1 (although it wouldn't be that much of a problem to just wait until there are 2 to process, I suppose).

    Maddermaxx,
    I hope I haven't hijacked your thread and that either:
    a) Your question has been answered
    b) You are gaining useful information from the rest of the discussion
    c) Possibly both ;-)

  3. #13
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    snowblind:

    Developer gets used up as you develop film. It takes a certain minimum amount of developing agent to cause film to develop enough to be usable. If you don't put enough of that agent in with the film, than the developer exhausts itself (runs out of capacity) before the developing cycle is finished.

    Within a moderate range, if you have more than enough stock developer in your mix, the amount of development of the film will not be constrained by the capacity of the developer, but rather by:
    1) how long you develop the film;
    2) at what temperature you develop the film;
    3) your agitation method; and
    4) how active your diluted developer is (varies with dilution).

    Most of us here use small tanks. The majority of us use film developer one shot - we discard the diluted developer after each batch of film is developed, rather than reusing and replenishing the developer. We refer to the capacity information, because we want to make sure that the developer we discard still has some life in it, rather than risking that it may exhaust itself in the tank before it has finished its work.

    DD X seems to be strange in a way. The recommended dilution and capacity information results, in the case of many of the small tanks, in diluted working strength developer that is very close to the capacity limits specified. As far as I am aware, most other developers are only likely to encounter problems with capacity in small tanks if they are used at non-standard, higher dilutions.

    I use HC110. There are a wide variety of dilutions used for HC110 (everyone has their favorite). The Kodak recommended dilution "B" has at least twice the needed capacity in most small tanks.

    With respect to experimentation, I would suggest that you are going to have to do some of that anyways. The published guides are just that - guides. If you end up using 120 ml of stock, and water to bring the tank up to being filled, you will end up with something like a dilution of 1 + 3.3. I'd try that with your development time reduced by 10% from the published times for 1 +4, and see what result you get.

    With respect to Simon R. Galley of Ilford/Harmann, I wouldn't hesitate to PM him (referring to this thread). Your questions are good ones, and any answers he might supply would help others. My perception is that one of the biggest reasons he participates here (besides the fact that he too loves analogue photography) is because it affords him, and through him Ilford, the opportunity to assist users of Ilford products (and probably encourage others to become users of Ilford products too .

    Here is an example post, to give you an idea of how helpful he can be:

    http://www.apug.org/forums/forum37/4...tml#post535898

    Matt

    P.S. Simon travels a fair bit, and sometimes therefore isn't able to respond immediately to a PM.
    Last edited by MattKing; 11-22-2007 at 08:38 PM. Click to view previous post history.

  4. #14

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    Quote Originally Posted by snowblind View Post
    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?
    250 is enough, but it just BARELY covers the film, so for precaution I'd use 300, and it's easier to mix to an even number than 250ml.

    The tank will not hold 600ml, it can hold 500ml with one reel, I'd say it might be a tight fit with 2 loaded reels, but could be done.

    I generally use D-76 non-diluted and toss it after a use, so I'm not replenishing it.. But I don't really see a problem with diluting chemicals in a 300ml solution for one roll of film, should be sufficient?

  5. #15

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    In answer to your question, No I have only ever used the 1510 tank which holds 1 35mm reel. I think if you use 250 in the 2 reel tank then coventional wisdom/instructions say put in the spare reel to avoid the bottom reel moving up and down. However it begs the question that if you want the reel to be covered by the developer then if it moves up and down with the developer then what's wrong with this? I think the answer to this lies in the surge effect that the reel moving up and down might have on the dev effect but that's conjecture on my part.

    What I can confirm is that when I use the 1510 1 reel tank the dev ends up in the top bowl of the tank, held in by the red rubber cup. On righting the tank the few cc's of dev takes a second or two to swirl back down the hole to the bottom as you will see if you lift the rubber top after righting the tank. In fact if you invert 4-5 times in a 10 sec period then some dev stays up in the bowl for whole inversion time. However I have never seen any adverse effect on the development of the film at the bottom of the reel. Hence my assumption, apparently borne out by the evidence of my eyes on examining the film after fixing that enough dev clings to the bottom of the film to ensure that there isn't uneven development.

    pentaxuser

  6. #16

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    Great, thanks everyone -- answers a lot for me. Probably asking a lot of questions for someone who's only starting down this road but I like to envisage a situation where accidentals are out of the equation, results are consistent and variances are deliberate. I'll get there!

    MattKing, I'll certainly PM Mr. Galley and, hopefully, we'll see his take on volumes and dilutions here soon...

  7. #17

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    P.S. Why do I have to login 2 or 3 times whenever I try to use this site?

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