Jobo developing instructions?

logan2z · May 10, 2022

I'm getting ready to develop my first roll of film in a Jobo 1520 tank and noticed that the instructions for the tank contain their own set of developing instructions:

For the developer: "Invert the tank a few times and tap it down on your palm to dislodge any airbells from the film. Invert and turn upright again every 10 seconds during the first minute, then once every 60 seconds [for the full development time]"

For the stop bath: "Pour in the stop bath. Pour out again after one minute".

For the fixer: "Invert once every 60 seconds [for the full fixing time]"

I've been developing Tri-X in HC-110 and using Ilford's Ilfostop and Rapid Fixer, and have been following the manufacturer's instructions for each. Those instructions differ fairly significantly from those in the Jobo manual.

Does anyone who uses Jobo tanks actually follow the Jobo developing instructions, or do you follow the instructions provided by the manufacturers of the film and chemistry? I'm inclined to continue doing the latter, but was curious if there's something specific about the Jobo tank design that necessitates following their instructions.

cmacd123 · May 10, 2022

I always use vigurous inversions at the start of developer to wring out airbells. I generally skip Stop bath, and invert at the start of the fixer, and otherwise invert the tank about once every minute. I also use a longer fixing time than recommended as the risk of underfixing is higher then the damage of overfixing..

the important thing is probably to be consistent.

AgX · May 11, 2022

logan2z said:
Does anyone who uses Jobo tanks actually follow the Jobo developing instructions, or do you follow the instructions provided by the manufacturers of the film and chemistry? I'm inclined to continue doing the latter, but was curious if there's something specific about the Jobo tank design that necessitates following their instructions.

There are different processing regimes concerning the rythm of agitation.
To me it is not even clear what agitation regime every manufacturer of developers applied. One author states that this standard applied would be 1 inversion every 3 seconds.
He tested different regimes and found for instance for Rodinal between this near continuous and a once-a-minute agitation a difference in needed time of factor 1.6.
Between different inversion regimes he did not find significantly different results , aside of needed developing time.

In any case, decide on one agitation scheme and stick to it for all developers.
(Unless the manufacturer explicitely prescribes a certain regime of his own.)

McDiesel · May 11, 2022

All agitation methods produce results. But the development time will differ. More agitation = less time.

By default I use the agitation method from a film datasheet. If the datasheet for HP5+ says that it takes 7 minutes and 30 seconds to develop it in ID-11 at 20C, then I use the agitation method from that same datasheet. Otherwise your agitation won't match your development time and you will have to find your own time that matches your agitation. That's annoying.

In practice this leads to me using Ilford's agitation method simply because I only shoot Ilford films, they assume this agitation method for all of their calcuated times, and those times produce great results, so have this method dialed into my Heiland TAS machine. This gives me predictable & consistent results. I also found that Ilford datasheets are more reliable than Kodak's that tend to be inconsistent and sometimes even contain errors.

Basically, B&W photography is Ilford's domain. Don't let Kodak or JOBO or a stranger on Photrio pollute your thinking

MattKing · May 11, 2022

McDiesel said:
By default I use the agitation method from a film datasheet.

So I think this means you are recommending the method from the Tri-X datasheet for the OP's Tri-X.
Here is the current link for that: https://imaging.kodakalaris.com/sites/default/files/files/products/f4017_trix_320400_1.pdf
The quoted JOBO instructions don't recommend agitation during the stop bath step. Other than that, I can't see any reason why they wouldn't work as well as the Ilford or the Kodak instructions.
Pick one, and use it consistently.

McDiesel · May 11, 2022

@MattKing heh I didn't even notice how my answer turned into an Ilford commercial

Agulliver · May 11, 2022

I was certainly taught to tap the developing tank a few times on the bench after pouring in the developer...to dislodge any bubbles etc. And to perform two inversions right away, and thereafter two inversions every minute.

It's worked for me for 36 years so far.

More agitation does generally mean less development time. Though doing something different in the first 60 seconds of a 10+ minute development won't make much difference, you might over-develop a film who's time is only 5 minutes. However, we all learn by experimentation what works best for us. You won't ruin your films either by taking Jobo's recommendations or by going with the film data sheet. You may find by practise that you prefer one over the other....or something between the two.

Don_ih · May 11, 2022

There's nothing special about the Jobo tank if not attached to the Jobo machine. It's exactly like any other small developing tank. So, whatever you did for a Patterson or stainless steel one, you can do to the Jobo - it just might leak less.

logan2z · May 11, 2022

Thanks for the replies everyone. I'll stick to what I've been doing with steel tanks/reels and see how that goes.

MattKing · May 11, 2022

logan2z said:
Thanks for the replies everyone. I'll stick to what I've been doing with steel tanks/reels and see how that goes.

Considering your posted problems with unexplained streaks, you may wish to give the films a bit more initial agitation than what I understand you have been doing.
FWIW, if the JOBO tank works similarly to the Paterson tanks, poured developer actually goes down the core and fills the tank up from the bottom, which is sufficiently different from how the steel tanks work that there should be at least a change in how the gremlins affect you.

logan2z · May 11, 2022

MattKing said:
Considering your posted problems with unexplained streaks, you may wish to give the films a bit more initial agitation than what I understand you have been doing.

Thanks Matt. I will probably try that.

MattKing said:
FWIW, if the JOBO tank works similarly to the Paterson tanks, poured developer actually goes down the core and fills the tank up from the bottom, which is sufficiently different from how the steel tanks work that there should be at least a change in how the gremlins affect you.

Yes, that's exactly why I want to give the Jobo tank a try. Hoping that tames the gremlins.

Jobo developing instructions?

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