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Thread: Advice on how to get correct E6/C41 temperature on Jobo CPP3?

  1. #11

    Join Date
    Apr 2020
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    216

    Re: Advice on how to get correct E6/C41 temperature on Jobo CPP3?

    The advantage of sous vide is that circulators typically use a hysteresis curve (probably some form of PID controller) so that as it approaches the target temperature, it backs off the power to the heating element. That way you don't get wild swings in temperature as the system chases it's own tail.

    If your bucket heater does the same thing, then fair enough.

    Otherwise you might be turning a little pail.

  2. #12

    Join Date
    Dec 2014
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    Iowa City, Iowa
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    Re: Advice on how to get correct E6/C41 temperature on Jobo CPP3?

    I have a couple Jobo machines, I've noticed that my CPP3 has a lower overflow level. I fill my machine with 40C water, I no longer use the solenoid valve in the machine. CPP3 requires me to fill to overflow, then I start the pump, let the upper level fill, then fill the lower until it's overflowing again. I have a TBE tempering box. I also will pour a portion of the chemistry into a beaker and warm in a dedicated microwave, I've been doing this for decades.

    Easiest for me is to put slightly overheated water into the machines or the TBE, I'm really careful because HOT tap water will trip the over temperature breaker.

    I run everything in manual so I can tweet temps. I can usually start up the machine, and by the time I get the film loaded it's ready to go.

  3. #13

    Join Date
    Dec 2014
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    Re: Advice on how to get correct E6/C41 temperature on Jobo CPP3?

    Quote Originally Posted by mikey1two View Post
    I have incorporated a bucket heater to get my jobo to temp within 30min from a cold start to develop e-6.
    The Sous Vide device looks promising as it has a thermostat that would shut the heater off when the temp is reached. I’m stuck pulling the bucket heater out as soon as the temp has been obtained. My bucket heater is rated at 1000W and the Sous Vide is at 800w (not much difference).
    Mikey

    This is genius

  4. #14

    Join Date
    Nov 2014
    Posts
    28

    Re: Advice on how to get correct E6/C41 temperature on Jobo CPP3?

    My bucket heater just continues to heats up to about 160f. The heating element in my cpp2 still functions, so once it reaches temp the machine will hold that temp on its own. The Sous Vide would be a better option if the heating element is not functional at all. At this point its more of a time saver.
    Mikey
    Quote Originally Posted by grat View Post
    The advantage of sous vide is that circulators typically use a hysteresis curve (probably some form of PID controller) so that as it approaches the target temperature, it backs off the power to the heating element. That way you don't get wild swings in temperature as the system chases it's own tail.

    If your bucket heater does the same thing, then fair enough.

    Otherwise you might be turning a little pail.

  5. #15
    Andrej Gregov
    Join Date
    Nov 2010
    Location
    Seattle, WA
    Posts
    140

    Re: Advice on how to get correct E6/C41 temperature on Jobo CPP3?

    I never put hotter water in the Jobo than my target processing temperature. You can hear the cold water inlet activating when you do and believe that caused some pump issues with my CPP3 which required a repair. I regularly process C41 and do not have long wait times to get up to temperature. Use hotter water when you're mixing your chemistry will speed up heat time for your chemistry once the processor gets to temperature. Also, I would avoid the "automatic" mode with the CPP3 where it guides you step by step through a development process. I'd keep it on manual and agree to avoid connecting to a cold water intake. I never found any of those automatic features worked particularly well. Keep it on manual and preheat your chemistry with hot water and you're likely 90% of the way to solving your issue. The additional heating element ideas are interesting but with a CPP3 class machine, they absolutely should not be necessary for a efficient workflow. If you're still having issues, you might reach out to Omar at Catlabs because maybe there's a mechanical issue with your machine.

  6. #16

    Join Date
    Dec 2014
    Location
    Iowa City, Iowa
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    1,205

    Re: Advice on how to get correct E6/C41 temperature on Jobo CPP3?

    I don't put "Hot" water in. I have thermostatic mixing valves in my darkroom. I fill the unit at 4 or 5 F above the target temperature. This just warms up the plastic and pump etc of the processor.

    Unless you have a chiller and circulation circuit hooked up to the Jobo solenoid valve I have found it to be of little value. Same goes for the older CPP2.

    Chillers used to be standard equipment with big darkroom sinks especially in industrial settings for graphic arts.

    If you lower the set temperature of the processor below the actual bath temperature, the solenoid valve will be energized, if you don't have COLD water at the valve the temperature can actually rise out of range, especially with black and white.

    These machines are great, but experience and following the instructions (somewhat sparse instruction pamphlet ) works.

  7. #17
    Drew Wiley
    Join Date
    Sep 2008
    Location
    SF Bay area, CA
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    14,744

    Re: Advice on how to get correct E6/C41 temperature on Jobo CPP3?

    Never use a tempering box as a quick heater or you risk damaging it. It's meant to sustain temperature. You want to start with water in it just slightly below your specified temp, and then if necessary, ratchet up the heat bit by bit, rather than all at once. If the ambient air is too hot, the opposite direction, then just dunk one of those little frozen "blue ice" paks in there to offset the extra heat, but not in direct proximity to the heater element. Recirculating thermoregulators way more precise than anything Jobo offers are available from scientific suppiers, and for around the same price range as good photolab equivalents were - roughly a thousand bucks apiece. But they can also be a fussy headache in certain ways, so if you don't need extremely tight temp tolerances, a tempering box is more realistic. Then there are automated mixing valves like Intellifaucet that can provide mixed hot/cold water at a certain temp. Many of us have used those too at one point or another. A used lab supply that handles Kreonite etc might have something like that at a discount price.

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