Jobo tank capacity vs Kodak's C-41 developing capacity

Discussion in 'Color: Film, Paper, and Chemistry' started by yelmarb, Sep 16, 2018 at 5:07 PM.

  1. yelmarb

    yelmarb Member

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    Reading the C-41 Z-manual about rotary tube processing and the capacity of "unreplenished solutions" Kodak states that you need 1 litre of developer to process 2 rolls of Portra 400 120. And the developer should not be used again.

    Kodak's recommendation is obviously the best way to go but.... it does seem like a lot of developer for 2 rolls of 120. It also means that I'm limited to developing 2 rolls of 120 at a time. What's the consensus with Jobo's tank capacity (in a CPP2 Processor) vs Kodak's recommendation?
     
  2. Sirius Glass

    Sirius Glass Subscriber

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    I use 500ml of chemicals which is the limit of most of my tanks and drums. I then return the chemicals back to the original bottle so that the last used chemical mixes with the rest of that chemical. I get about 12 to 16 rolls or roll equivalents per 1 liter solutions.
     
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    yelmarb

    yelmarb Member

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    Is that processing in a rotary processor? If so, that's 8x more developing than what Kodak recommends. Do you adjust the developing time for that 16th roll?
     
  4. pentaxuser

    pentaxuser Subscriber

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    Something doesn't add up here. My Jobo 1520 tank needs 240ml for rotary processing and will do 2 x 120 films if you use the separator clip that allows you to feed 2 x 120 films on the reel. That's 8 films for 1 litre(960ml to be strictly accurate ) even if you use and dump each 240ml after every 2 x120. Even if you develop singly that 4 x120 films per litre

    I wonder where Kodak gets the figure of 500ml per film? Can you give us the Kodak quote from the Z manual to help clarify matters? Thanks

    pentaxuser
     
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    yelmarb

    yelmarb Member

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    Here you go...
     

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  6. Sirius Glass

    Sirius Glass Subscriber

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    It depends on the tank. The 3010 takes 500ml, the 1540 takes about 500ml. That is the maximums of the tanks. As stated before I add the used solution back to the 1 liter bottles. I do all the processing in two or three days, adjusting developing times as I continue to develop per the instructions.
     
    Last edited: Sep 17, 2018 at 2:06 PM
  7. Mick Fagan

    Mick Fagan Subscriber

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    I’ve just reread my copy of Kodak Z-121A C41 manual, which as far as I understand it is the original C41 manual; dated 1975. Whatever, it was the first one available that I know of in Australia.

    No mention is made of actual capacities like the current electronic manual you refer to, so essentially one would have to guestimate.

    I started doing C41 in my Jobo around 30 years ago, at the same time at work we were running a Dip ‘N’ Dunk C41 machine with monitoring using Kodak control strips.

    Pretty much the only way you can be certain is to run control strips then either check them yourself, or take them to a lab and get them to check them.

    Using a 1520 tank with a 1530 module bolted on, one can run up to 4 x 120 films and a single 35mm film, or in my case a 35mm control strip. I remember trying various combinations with a control strip inserted and eventually came up with various strategies. This is using 600ml of solution, not 1 litre.

    For 135 the maximum that could be done and keeping the control strip within the parameters, was 8 rolls of 135 x 36 frames per 1 litre.

    With 120 film between 3 rolls and 4 rolls were usually within the parameters; although if my memory is correct, it was just within the parameters with 4 rolls.

    Eventually I settled on using a 1540 tank, 1510 + 1530 module, minimum solution is 470ml, I always used 500ml of solution. With this and using C41 120 film, I developed 2 x 120 rolls per 500ml of go juice. Did that on and off for about 20 years, worked a treat. That of course doesn’t mean it was on the money from a technical point of view, but it was pretty good and the colour prints I obtained were at times devastatingly good.

    You need to understand that Kodak invented the process, they were the best ever technical company to deal with and if they suggest that so many rolls of film per litre is the go; then you can bet that suggestion is correct for perfect developing.

    One can always deviate and still get wonderful development, day in day out, many do and I did. Just remember to carefully observe your results with what you develop and choose which parameters are acceptable to you.

    As a matter of interest, all of the control strips that I did in my Jobo, were super consistent when compared to the control strips that went through our Dip ‘N’ Dunk C41 machine. This is a normal state as the replenishment system can sometimes be thrown off kilter with sporadic film numbers going through, followed by heavy throughput, then nothing for an hour or so then off again with a shed load of 8x10” and 4x5” interspersed with maybe 30-40 rolls of 120 going through when a job lot came in for processing.

    Disclaimer: I haven’t done C41 for close to three years now, although I may in the near future as I recently picked up some 4x5” C41 film; 40 sheets of Ektar 100. :D

    Mick.
     
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    yelmarb

    yelmarb Member

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    Hi Mick, thank you for the reply. So when developed 2 x 120 in 500ml of developer, did you discard the developer afterwards?
     
  9. Mick Fagan

    Mick Fagan Subscriber

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    Yep, always did One Shot developing with C41, never any other way. One shot is the go for super consistent results, replenishment is alright if you have the throughput.

    According to Kodak, doing batch processing, even one shot, is not as consistent as replenishment processing. In the main I would agree with them, but if a bath sits around for half the morning doing nothing, then gets hit with the mid-morning rush, then stops again for lunch followed by another serious hit mid afternoon, replenishment is not quite as consistent as one would hope. That is the experience I have.

    We used to start the baths up around 0730hrs, temp was up and looking good 1 hour later when the first control strip would go through, then we would make adjustments, another control strip and so on. Usually the C41 was up and running between 0930h and 1000h, E6, because of the longer process time, could sometimes be ready around 1030h but more often it was on the money around 1100h when it would be hit with a shed load of stuff for a couple of hours.

    Just as a matter of interest, my ancient CPE2 has a slow speed, all of my film has been developed at that slow speed since I have had the unit; around 30rpm from memory. B&W, C41, E6, B&W reversal, lithographic material and almost any other film process you could imagine. Used the faster speed for paper processing.

    Mick.
     
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    yelmarb

    yelmarb Member

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    Did you also do one shot with bleach and fixer as well?
     
  11. Mick Fagan

    Mick Fagan Subscriber

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    Ha ha, never; always used bleach and fixer baths for double the amount of developer. You'll know if you use exhausted bleach.

    I did in fact re-halogenate my bleach, not recommended, but I did it for about 15 years. If you study bleach aeration under, Processing Solutions and Their Effects.

    Mick.
     
  12. JWMster

    JWMster Subscriber

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    I've used the 2500 series Jobo tank that accommodates 3 reels of 120 at a time - each with 2 rolls of film rolled on (total of 6 rolls). I've mixed up 1 litre of chemistry using Tetenal C41 and had no issues running 3 tankfuls - a total of 18 rolls. I use 600 ml of chemistry per run and pour the expended chemistry back into my 1000ml containers that I used to make the stuff originally. I have followed the time adjustment recommendations in the Tetenal instructions, but seriously, it isn't a big adjustment. Something like adding 15 seconds for each tankful. I've done this with Kodak Portra 400 and then scanned the negatives in a Nikon scanner. If you're printing your images in a wet darkroom, your mileage could vary significantly. Fuzziest part of this is my memory on the time adjustment, but frankly, I was underwhelmed by the "sensitivity" to time adjustment. I'm sure I could try NOT doing that, but I'm too conservative and tend to go with a manufacturer's instructions. From the research I've seen here, plenty will stop at 2 tankfuls (12 rolls), but almost as many suggest you can do 18. The population of Jobo users recommending more than 18 rolls can be processed from one set of chemistry seems to fall precipitously. I have processed at recommended temperature, but frankly, my experience with C41 is slim: I've done 5 tankfuls - total 30 rolls of C41. I've done 100's of B&W but C41 was something I began using only this past summer. FWIW, I prefer to use the 2500 tanks because I find it easier to get 120 film on these rolls where the flange width is visually wider than the reels for the 1500 series. The 1500 series works fine for 35mm, but didn't load nearly as easily with modestly thicker film emulsion used by 120 (is this true or just my finger's tactile experience?). Your mileage may vary.
     
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