Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,940   Posts: 1,557,497   Online: 931
      
Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 26
  1. #11
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,293
    Images
    12
    Jobo Drum Capacities - that tells you how much you need to cover all the film in the tank. You also need to think about developer capacity which is about 16 rolls/L (64 sheets/L) of working solution with most professional-grade C41 chemistry (Kodak, Fuji, Rollei, etc). So with 12 sheets, you need at least (12/64)L=188mL and you will exhaust the chemistry in one go. Clearly 188mL isn't going to physically cover the film, so you use the tank-minimum instead.

    If you're processing the developer to exhaustion by extending times (like the Fuji kit does), then you would make up a 750mL batch and use it 4 times to process a total of 48 sheets, which is 3/4 of 64 sheets just like 750mL is 3/4 of a L. If you're doing replenishment, then you make up a 1L batch and after each process, replace some fraction of it according to how much film you processes. 12 sheets is 3 rolls and at 50mL/roll replenishment, you would take 150mL of fresh developer (without starter) and top that up with 850mL of reused developer then use that 1L for the next batch.

  2. #12

    Join Date
    Jul 2005
    Location
    USA
    Shooter
    Large Format
    Posts
    1,322
    Images
    3
    I was with you most of the way before my brain numbed with calculations, but the bottom line question I have about the Jobo drums is, can they be considered economical if they require reuse of the solution in order to meet the minimum capacity? Is it a good economy with good reliable and consistent results, or is it a bad econony with savings coming at the expense of consistency? I was never satisfied with results when partially reusing Ilfochrome chemicals, although it suited others. And that's my only experience in reuse of color chemicals, so I'm wary of total reuse. .

    Although I'd like to do more than 4 sheets, Kilgallb's 90 ml per 4 sheets @ one shot use is much more attractive to me right now, assuming that gives me results I like.




    Quote Originally Posted by polyglot View Post
    Jobo Drum Capacities - that tells you how much you need to cover all the film in the tank. You also need to think about developer capacity which is about 16 rolls/L (64 sheets/L) of working solution with most professional-grade C41 chemistry (Kodak, Fuji, Rollei, etc). So with 12 sheets, you need at least (12/64)L=188mL and you will exhaust the chemistry in one go. Clearly 188mL isn't going to physically cover the film, so you use the tank-minimum instead.

    If you're processing the developer to exhaustion by extending times (like the Fuji kit does), then you would make up a 750mL batch and use it 4 times to process a total of 48 sheets, which is 3/4 of 64 sheets just like 750mL is 3/4 of a L. If you're doing replenishment, then you make up a 1L batch and after each process, replace some fraction of it according to how much film you processes. 12 sheets is 3 rolls and at 50mL/roll replenishment, you would take 150mL of fresh developer (without starter) and top that up with 850mL of reused developer then use that 1L for the next batch.

  3. #13

    Join Date
    May 2011
    Location
    MA, USA
    Shooter
    Large Format
    Posts
    1,255
    Images
    19
    If you get a 5L kit, liquid, then all the elaborate calculations above are not needed.
    Use Developer as one shot, straight, mixed as per instructions in the box, at minimum stated of Jobo tanks (or any other you will use, though Jobo's are pretty economical), and you will still achieve the max capacity of the developer (if running 6 sheets at least per run).

    I am not sure what the results of using the ciba tanks are, but i know many folks use them and are happy, that is not say the results are "good" or meet any kind of specific guideline.

    C-41 is usually *** processed at 38.4C, which is about 101F, and to make things easier most manufacturers will mark at 100F or 38C. Dev time is 3:15, for starting point at that temp.

    Even if you will still have some dev capacity left, its worth that little bit of "waste" to make sure you have the same perfect results time and time again. One shooting the Dev is the way to do just that. Bleach Fix or Blix can be re used with no ill effects, and you can always re blix as needed if its dead, but even then, with any kit you buy, you will have X3 the amount of blix material compared to the amount of dev you have, even if used to exhaustion.
    CatLABS of JP
    Darkroom resources and service

    www.catlabs.info | https://www.facebook.com/CatLABS.of.JP | www.jobo-usa.com

  4. #14

    Join Date
    Sep 2010
    Location
    Castle Rock, CO, USA
    Shooter
    Multi Format
    Posts
    1,427
    Images
    66
    Quote Originally Posted by CatLABS View Post
    All c-41 kits are not equal, and a liquid, single part mix, long lasting system is what you want, one shot is always best to minimize the chance of contamination. One drop of bleach or blix in even a very large container of color developer, will make the whole batch unusable.
    Omer, does your kit's instructions tell how to extend the time when re-using? Because of the size of my tank I will have to use at least a liter of fluid for each step. This would be for 12 4x5 sheets or 5 35mm so one-shot would be prohibitively expensive.
    “You seek escape from pain. We seek the achievement of happiness. You exist for the sake of avoiding punishment. We exist for the sake of earning rewards. Threats will not make us function; fear is not our incentive. It is not death that we wish to avoid, but life that we wish to live.” - John Galt

  5. #15

    Join Date
    May 2011
    Location
    MA, USA
    Shooter
    Large Format
    Posts
    1,255
    Images
    19
    What drum are you using?
    CatLABS of JP
    Darkroom resources and service

    www.catlabs.info | https://www.facebook.com/CatLABS.of.JP | www.jobo-usa.com

  6. #16

    Join Date
    Sep 2010
    Location
    Castle Rock, CO, USA
    Shooter
    Multi Format
    Posts
    1,427
    Images
    66
    There is no model number on it that I can see but I believe it is a 2336 from pictures on the web. It has 2 2021 reels for 4x5. For 35mm and 120 I have the older white reels that stand away from the wall of the tank by a couple cm. They are tight enough to the core that they don't slip. So it pretty much requires the center axis be covered with liquid.
    “You seek escape from pain. We seek the achievement of happiness. You exist for the sake of avoiding punishment. We exist for the sake of earning rewards. Threats will not make us function; fear is not our incentive. It is not death that we wish to avoid, but life that we wish to live.” - John Galt

  7. #17

    Join Date
    May 2011
    Location
    MA, USA
    Shooter
    Large Format
    Posts
    1,255
    Images
    19
    I do not have any documentation for the older Jobo tanks, but if you will be using it for rotation, with the 2021 reels, you only need the total amount of liquid inside the drum to be higher then the highest point the film will be loaded, which is not much at all. For roll film this might not be the case, and you will need more chemistry to cover the entire surface.

    The instructions on our kit only have general info RE re use, and we have only tested one stage re use at + 10% per liter (about 3:45 for dev) and found no significant difference in density. We did not test any further.

    For you though this might be worth while testing with some test rolls and see how far the material can be re used before exhaustion.

    In short - while the 2021 reels and tank you have might be ideal for pretty much anything, it might not be the ideal tool for C41, with roll film, due to the high volume needed. For that all i can say is the the Jobo multitank system (2500), covers that problem, and gives you exact(and fairly economical) numbers for either 4X5 (2509n reels), 35mm and 120/220 (2502 reels). The cost of buying the equipment should be weighed against the cost of chemistry needed over time with the current tank, but thats just my opinion.

    I hope this answers your question.
    CatLABS of JP
    Darkroom resources and service

    www.catlabs.info | https://www.facebook.com/CatLABS.of.JP | www.jobo-usa.com

  8. #18

    Join Date
    Sep 2010
    Location
    Castle Rock, CO, USA
    Shooter
    Multi Format
    Posts
    1,427
    Images
    66
    Yes, very helpful. Thank you.
    “You seek escape from pain. We seek the achievement of happiness. You exist for the sake of avoiding punishment. We exist for the sake of earning rewards. Threats will not make us function; fear is not our incentive. It is not death that we wish to avoid, but life that we wish to live.” - John Galt

  9. #19
    polyglot's Avatar
    Join Date
    Jun 2009
    Location
    South Australia
    Shooter
    Medium Format
    Posts
    3,293
    Images
    12
    Quote Originally Posted by CatLABS View Post
    If you get a 5L kit, liquid, then all the elaborate calculations above are not needed.
    Use Developer as one shot, straight, mixed as per instructions in the box, at minimum stated of Jobo tanks (or any other you will use, though Jobo's are pretty economical), and you will still achieve the max capacity of the developer (if running 6 sheets at least per run).
    Pretty sure that's not true. C41 dev capacity is 16 (Fuji) to 20 (Rollei) rolls per L, which is 64 to 80 sheets per L. The most efficient Jobo tank for 4x5 I think is the 3010 ($$$) which needs about 250mL per 10 sheets fully loaded. If you one-shot with that tank and the minimum fluid quantity, you're getting about half of the developer's rated capacity.

    If you use 2509s, it's worse (6 sheets in ~300mL).

    Seriously, reusing C41 developer is not a problem and does not cause consistency issues. I find it works nicely if I replenish it - I have a 1L working solution of Rollei and replenish it at 50mL per roll that goes through it. No time adjustment required and it's exactly the same process that pro labs use and for which the C41 process was designed. Just make sure you keep the working solution completely air-free in a good bottle between sessions and refrigerate it if it's going to be there for a while (more than a couple weeks). I've kept a Fuji working solution for 4mo in a fridge and it worked identically before & after (I did 3 identical test rolls to measure developer life).

    You can reuse the bleach+fix about twice as much as the developer, so definitely don't one-shot those. Bleach is expensive! You can buy a Fuji 5L kits, use 1/2 or 1/3 of the bleach+fix, then just buy Rollei bulk developer (cheap) to use up your remaining bleach+fix capacity.

  10. #20

    Join Date
    Sep 2010
    Location
    Castle Rock, CO, USA
    Shooter
    Multi Format
    Posts
    1,427
    Images
    66
    Quote Originally Posted by polyglot View Post
    You can reuse the bleach+fix about twice as much as the developer, so definitely don't one-shot those. Bleach is expensive! You can buy a Fuji 5L kits, use 1/2 or 1/3 of the bleach+fix, then just buy Rollei bulk developer (cheap) to use up your remaining bleach+fix capacity.
    This is good to learn. My local store sells C-41 chemicals separately, both Kodak and another brand in consumer and commercial sizes.
    “You seek escape from pain. We seek the achievement of happiness. You exist for the sake of avoiding punishment. We exist for the sake of earning rewards. Threats will not make us function; fear is not our incentive. It is not death that we wish to avoid, but life that we wish to live.” - John Galt

Page 2 of 3 FirstFirst 123 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin