Questions about Jobo CPE2/CPA2/CPP2

[j.l._kennedy1]

I am interested in obtaining a Jobo processor for b&w 4x5 film

developing and have a few questions:

 

Is it worth obtaining the CPP over the CPA. As far as I can tell the

only difference is slightly tighter temperature control which is not

critical to b&w film processing, and a cold water solenoid which I

presume will allow the processor to lower the temperature in addition

to raising it. However, I am assuming that even the CPP processor

would not be able to lower the temperature any lower than the

temperature coming from the tap. Is this correct? As an aside, I am

also wondering if anyone has ever figured out an economically

feasable way to lower the temperature coming from the tap.

 

In light of the first question, is there any advantage to processing

at 68 degrees or is 75 degrees just as good, after adjusting the

developing time? I currently use Tri-x/HC-110 but may try Tmax in the

future.

 

Lastly, if I am only developing b&w film, should I consider the CPE2?

 

Sorry, one more! I have noticed some eBay sellers saying that their

Jobo is the same as the new model except for the electronics. What is

the advantage one gets from the "new electronics"?

[scott walton]

For water to be chilled from the tap you would need a small chiller. IMO, 68 degrees is the optimum temp. I use 7.5 minutes for dilution B @ 68 degrees and 75 degrees would be to short risking uneven processing. Automation is a good thing as far as processing. It gives more consistency. With this in mind, go for the one that has the most! Sorry about your questions on the electronics, don't know the answer...

Cheers

[hyperfocal]

I have a CPA-2. You are correct about the differences between the CPA-2 and CPP2. You won�t have any trouble keeping the temp at 68/75, but the 40C for E-6 is a bit more difficult. The cold water intake doesn�t seem worth paying extra for, as the tap water is often above 68 degrees. A bag of ice works fine.

 

One thing to be aware of is that in the CPA-2, there appears to be no link between the temp dial setting and the actual water bath temp. I dial in the temp I want, then watch the thermometer and adjust accordingly. One thing I�ve noticed, especially in the winter when my house is cold, is that placing the drum on the unit will lower the water temp. I have to adjust the temp dial and let the temp equilibrate. This is especially true of E-6. Normally on E-6 (which is much more temp sensitive than B&W, IMHO) I measure the chemistry temp in the bottle before dumping it in the drum.

 

Another issue with both models is that the top water bath temp may be different, by a bit, than the water at the bottom of where the bottles are seated. A body with a CPP2 noted his chemistry temp was a bit different than what his digital thermometer readout showed. Not really an issue if you�re aware of it, the big deal with the JOBO is consistency and being able to walk away and drink a beer while it does the work.

 

You will need a lift to do it right.

 

H

[dan_smith]

The 'slightly tighter temp control' will be useful if you go to processing TMax films. They require temp control as tight as color film to get consistent results. They were developed & tested with Jobo processors and the consistency offered using these processors helps assure higher quality processing results.

The usefulness of the cold water solenoid will be worth it in many areas where the water temperature from the tap is below what you are processing at. In our area it seldom gets above 55 degrees even during 100 degree summer days and in the winter hovers in the mid to high 3o's.

TMax testing was done at 75 degrees. The reason 68 is used as a standard is that (per Kodak historians I have talked with) the water temp in Rochester was 68 degrees. TMax is a different animal than more traditional films and works well at 75. Either way, stay consistent & your results will be better. With Kodak recommending 75 for Tmax, having a processor that will maintain temperature within a half degree will only help you in getting consistent results. As for an economically feasible way to lower water temperature coming from the tap... move to an area where the water temperature is lower than where you live.

Buy the CPP. Having the tighter tolerances is worth the extra investment.

[dk_thompson]

just out of curiosity, don't the Jobos use a pre-heat cycle of some sort for the E6 processing? Your description of the drum causing the temps to drop, sounds like a recipe for disaster as far as E6 goes....another issue with E6 is alot of the newer emulsion films and the new kodak kits did away with prewet steps...if a processor can get to the right temps in it's tube by some means other than water, this would be a plus...otherwise you might have some consistency problems with film speed and color balance....but you have to figure in all sorts of variables for process control like stainless reels throwing off the tube temps etc. We run thousands of sheets of TMX 4x5 a year through a deeptank at 75 degrees, and use a waterchiller too, but my experience here has been that a drift of a degree or so during processing is nothing, I don't find b&w--even tmax films--to be as sensitve as E6....of course, it might be different for you all...

[rw_hawkins]

You can't go wrong with the Jobo processors they are great. One note, I have had a CPE2

w/ lift for ages now and I wish I had a CPA2 for one reason, the expert drums. This is

the drum with 5 separate chambers for sheet film and is the best solution for 4x5 film

development. Unfortunately it is too big for the CPE2.

As for temperature, I live in California and tap water during the summer is quite warm.

I have adjusted my HC-110 dilution way down so I can develop for 8 minutes in the Jobo

at 75 degrees (you need to test not just because of temp. but also the Jobo agitation is

stronger than if you tray develop). Just do some tests and your negatives will look as

good as always.

[david_m._young]

Hey.... been using a CPP for several years and I can't recommend them highly enough. A couple of tips:

<br><br>

I've got a link explaining the "new electronics" and can send it to you if you drop me an e-mail (I'm replying to this from work and the link is at home). As I recall I didn't see any appreciable advantage to them and haven't updated. Either way you can buy the kit from Jobo and install it yourself.

<br><br>

Get the CPP or the CPA... you'll want access to the Expert Drums for 4x5 and the CPE can't handle it.

<br><br>

the cold water solenoid allows you to hook up a cold-water source to your processor so the water won't warm up on a hot day.

<br><br>

Me??? I don't see a need for it. On those days that he water warms up, I put a couple of "ice packs" into one of the chemical bottle slots. It's important to not use ice cubes, or any free-floating ice as it can get into the water pump and break it. I picked up a few of those blue plastic "ice replacement" thingies that they sell at the local market, and keep them in the freezer. The packs keep the temp own, the heater warms it up, and they balance each other to the perfect temp.

<br><br> a drum with film in it is not going to change the temp in a CPP or CPA... there's just to much thermal mass to balance it. Don't worry and keep going.... there's no beter way to do E6 at home.

<br><br>

Hope this helped!!<br>

Cheers, D.

[michael_wellman]

I have the CPA-2 and have had good reults with it using for B&W and occasional color. The temp for me has been pretty close to the dial setting, but it's a good idea to watch the temperature on the thermoter and not trust the dial.

 

As for the cold water celanoid the cheap way of doing this is to freeze a bottle of water and put it in your water bath. This will lower the water bath temp and the processor will warm the water up to the temp you have set. This is somthing I have to do in the long summers down here in Austin where the water temperature is 82.

[scott_jones2]

I have the CPP and really like the cold water solenoid. No fussing with the ice and less electricity consumption on the heater. BUT I have home tap water that averages 60 degrees or less even in the summer which makes this work. If your tap water temperature gets higher than your desired temperature in the summer then this will not work. I also like the convenience of the dial in temp setting on the CPP and thus don't have to mess with thermometers at all. The machines are great. I even do my fiber prints in them (gasp!) and they work great and I use very little chemical and no odor in my darkroom. But thats another story. I second the other comments that not having a lift would be nuts. . .

 

Scott

[mehmet kismet]

I agree with David M. Young, so that the essential for Jobo processors for 4x5 or larger format is to use the expert drums(3010 or largers)

You can choose between CPA2 or CPP2 if you intend to use it only for BW. And the accessory Jobo Lift is very usefull. One must be carefull about the minimum amount of solution, for very diluted developers like PMK, or Rodinal with more dilution than 1:75. You should increase this min. amount depending of the developer and the corresponding dilution.

[bruce watson]

I've got a CPP-2, and use it for Tri-X at 20C. Today my tap water was running at 27.4C (that's August in the South for ya). There is, in fact, an economical way to reduce the tempering bath to 20C and hold it there.

 

All praise to engineers! This method is called "ice." I dump a bunch of ice in and let the water circulate. Takes about 20 minutes to stabilize. If I put too much ice in, the Jobo flicks on its heater and pulls temperature back up to 20C. Excess water from melting ice just goes out the overflow tube.

 

As you process, you can watch the temperature rise. I've found that if I add one cube when temp. hits 20.1C, it cools right back down.You can't ask for much easier.