Jobo dev. times

ron3865

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I recently bought a CPP2 and thought I'd try my hand at 120 and sheet film processing and after doing a bunch of reading on the subject I have a few questions that I know I can get answered here.
As far as development times go I've seen everything from "use times and dilution listed on film" to "add 15 secs." to "subtract 10 secs." and to use stock solution,...or some say to dilute.
I'm going to start with D76 and I think if I can get the dev. part "right" the first time I'll be better able to tell if there is something amiss anywhere else.
Thanks in advance!
 

pentaxuser

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I have not used my Jobo for B&W processing so cannot speak from experience but certainly Ilford recommend 15-20% reduction. However a guy called John Tinsley did use a Jobo for B&W and wrote a very good book on the subject of rotary processing in general. He used normal inversion processing times BUT also used a pre-soak. He believed that using the pre-soak negated the need to shorten dev times compared to hand inversion.

Worth bearing in mind if a pre-soak is part of youyr normal routine.

pentaxuser
 

grahamp

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I use a pre-soak (usually a couple of minutes), then FG-7, usually at 1:11 or 1:15 dilutions (Delta 100 / HP5 in 5x4 and Delta 400 in 120/35mm). I find that my times are much the same as I would use in a hand tank inverted every minute. My CPE2+ with lift empties and fills faster than the hand tank, so there is a slight adjustment there. I would run a direct comparison. I don't think you will have to extend time with the Jobo, but you may not need to make a large reduction either.

Don't forget that the Jobo tanks have minimum and maximum capacities for solutions, and this divided by the active ingredient volume governs the amount of film area you can process. This is not always what the tank will hold. FG-7 at 1:11 will do 3 x120 in 570ml, but the tank will accept 6 x120. D76 at common strengths ought to be better in that respect.
 

Lee L

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Jobo has made a number of suggestions for development time adjustments over time. Last I heard a 5 minute pre-soak was recommended, followed by normal small tank intermittent inversion agitation times. Without the pre-soak something in the neighborhood of 15% (not 15 seconds) reduction in development times over small tank intermittent inversion agitation was recommended. Both of these methods are approximations for determining your own times.

There is (was?) a Jobo website with back issues of the Jobo Quarterly that have articles on just this issue. I've typed it in here on APUG several times before, as have others. One's in this thread: (there was a url link here which no longer exists)

However, just checking that link, it appears that the internet host is now gone. I'll see if I can find something else useful.

Lee
 

nworth

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I've found times to be slightly less ( 8 to 10 percent) than what is listed for small tank processing.
 

Lee L

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Since this often comes up, and the server for the Jobo Quarterlies appears to have been taken off line, I'll attach a pdf rendering of the summary article (not the entire JQ issue) on presoaking. Moderators, feel free to delete this if it's not perceived to be within "fair use".

Lee
 

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Venchka

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Jobo 2553 or 3010 tanks.

HP5+ @ E.I. 250, 120 or 4x5 sheets

Pre-soak followed by Xtol 1:3

Uniroller or Beseler motor bases for agitation

9 minutes @ 20C is my base time. Kodak's time for this combination is about 11 minutes.
 
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edtbjon

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A little bit on presoaking with Jobo rotary processors. (This can be found in the Jobo Bulletins linked etc. above, but some quick info.)
For b/w film Jobo recommends 5 minutes prewet. (I personally havn't written this time "in stone", just a few minutes or so to fully soak the film.)
The one exception is when Xtol developer is used. Then NO prewet should be used. (This is because there have been problems with uneven development when using Xtol and presoak.)

In general, when using a prewet, you can add 20 seconds to the developing time to compensate the time it takes for the developer to get into the emulsion. In my mind, presoak never hurts and when the developing times are short (5 minutes or shorter) it really helps in getting more even and consistent results.

My personal dev times using a Jobo CPP2 are slightly shorter than the recommended "normal" times, but it's not a "staight 10%", but varies in between 5 and 15% for different combinations.

//Björn
 

Venchka

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I have not had any problems with a pre-soak and Xtol diluted 1:3 with Ilford HP5+ film.

For every rule, there are exceptions.
 

Lee L

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Venchka said:
For every rule, there are exceptions.
Click to expand...
That's pretty much the point of the Jobo Quarterly article. There is no single method for converting small tank intermittent agitation times to Jobo rotary development that works in exactly predictable fashion for everyone, or for every film / developer combination.

Lee
 
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jp80874

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If you use up to a litre of fluid, which I do with Rollo Pyro in Expert tanks, remember that it takes roughly 20 seconds to pour it in and another 20 sec. to pour it out. You need to decide how much fluid you will be using and what percent of that time should be counted. It matters more that you are consistent than how much time you call it. Once you have a pattern then you can adjust the time to attain "the perfect" negative. That all assumes your exposures and temperatures are consistent.

John Powers
 

Mahler_one

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Consider doing very simple film tests in order to get exact parameters for developing whatever film you chose, at whatever temperature you use, using whatever developer you desire. For the cost of about a box of 4x5 film you can save yourself hours of experimentation ( unless you enjoy such experiments ), and lots of possible frustration. Remember that all of our good members have slightly different techniques regarding materials, dilutions, time, temperature, etc., etc. What works for them might be completely wrong for you. I have no financial or other interest in any concern that does such tests. However, I do know that Fred Newman at The View Camera Store does such testing, and I am certain that others on this thread know of individuals who also can help you. If you need further information please feel free to contact me privately.
 

Mick Fagan

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I have been using a Jobo CPE2 for around 20 years now. I have a fairly good system in place and plenty of records to give me processing times.

However, last week I was presented with a film and developer combination I had never used. Tri-X 400 and Ilford Ilfotec LC29. They were not my films or developer, but one of my students work.

As she is at a stage where decisions need to be made by her, she decided to go with the times published on the Harmon site.

No Pre-wet, dilution at 1+19 and processing at 21ºC. The films were very printable with most of them being printed at grades 3 to 3¼.

The next lot of films were processed with a ¼ of a stop more processing time, they printed at grades 2¾ to 3. She will be sticking with the this later, time, temperature and developer combination outcome for future use, it works well for her.

You can do a pre-wet or none, whatever you find works well, keep on doing it. I would suggest that the manufacturers published developing times with their films and developers are quite close for starting points. That is the experience of myself, and the students I have taught.

Mick.
 

MikeSeb

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I've found that I need at least a 15% reduction in development times over "small tank, hand inversion" times; and 5% or more less than "rotary processing" times, when those are published. This applies to the Jobo ATL-1500, which has a fixed rotational speed. I use a 5 minute presoak with all B&W films for the reasons others here have stated.
 
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