JOBO CPA-2 temperature control

**Steve Williams_812** · 2-Jul-2000, 20:04

I want to get a JOBO processor to process 8x10 film and 120 film. Can anyone gi ve me an asessment of the CPA-2's ability to control temperature. Most of the f all, spring, and winter the darkroom is cool, but in the summer it can run to ar ound 75 degrees. Will the CPA-2 keep the bath at 68 dgrees or do I need to step up to the more expensive CPP-2?

thanks,

steve

**William Marderness** · 2-Jul-2000, 20:20

Both processors have a heater, but no cooler. The CPP-2 does not cool water. It just has a value to which you can attach a hose coming from a cold water line, like those used for washing machines. Cold water from the line goes in, while the warmer water in the processor goes out. An easy way to keep the water cool is to put blue ice in one of the spaces for bottles or freeze water in one of the bottles. Jobo recommends this somewhere on their website.

I have had both processors. It takes a while to set the temperature of the CPA-2. Once you set the temperature, the next time you use the processor, you may have to set it again. I moved to the CPP-2 to set the temperature more easily. You should still use a regular thermometer as the standard, however. I have noticed that the digital temperature readout drifts a bit.

**Mike Kravit** · 2-Jul-2000, 22:21

Steve,

Here in South Florida the tap water temperature is roughly 76-78F all year round. I have a CPA-2 and find that sice my darkroom is cooled to 70F the water in the JOBO resivoir remains pretty much on target. I do not recommend leaving water in the JOBO for extended periods of time as algae will begin to grow.

I empty it between uses and them fill it with water from my chiller before use. This way the water once filled stays at 70F.

I also have found that the temperature control on the CPA-2 needs to be calibrated with a good thermometer. However once marked, it holds the temperature fairly well. As you can probably surmise, I use the JOBO only for B+W film and enlarged negatives. I guess it is habit, but I just love seeing images pop up in trays.

Regards, Mike

**Ian_5787** · 17-Aug-2005, 10:26

If anyone is looking for spare parts or wants one. I'm selling a CPA 2 Jobo for $150 so send me an email and I will send you some pictures. I live in the tampa are and just want to get rid of it. I can ship it as well.

**Tom Westbrook** · 17-Aug-2005, 12:07

My basement isn't air conditioned, so I the frozen bottle method of cooling (see below). It usually takes one frozen bottle to keep things down to 68F during a single processing run, but if room temp is above 77F or so (like it has been lately) it usually requires two bottles.

Jobo mentions this on their web site

If you wish to cool a CPA-2 processor below room temperature, or cool a CPP-2 processor below room temperature (without using the cold water Solenoid), use the following procedure: Fill unused or extra 1000 ml bottles with water, and cap loosely. Do not put more than 1000 ml in each bottle. Place the bottles in a freezer or refrigerator until frozen or cool. Put these bottles into unused bottle slots. Set the temperature on the processor to the desired process temperature. Let the processor run until the correct temperature is obtained. Be sure to check the temperature of the chemicals and rinse water. Run the process when all temperatures have stabilized at the desired point. You may need to exchange chilled bottles periodically in long processes (extra bottles already cooling in the refrigerator would be useful). The chilled bottles constantly cool the water bath, and the heating element of the processor heats as necessary to bring the temperature up to the process temperature. Alternatively, re-freezable 'ice packs' (Blue Ice) may be carefully placed in the trough. Be sure the pack does not interfere with the moving parts of the processor.

**Antonio Corcuera** · 13-Oct-2006, 02:36

Anyone getting consistent results developing C-41 on the CPA-2?
I've been offered one of these processors and after reading the differences with the CPP-2 at the Jobo website, I'm worried about the 0.2ºC temperature margin.

Jobo states: "The CPP-2 uses an integrated digital thermometer which allows it to hold the temperature of the process to within +/- 0.1 deg C. The CPA-2 uses a different temperature probe which holds the temperature to within +/- 0.2 deg C. This is really only an issue with the C-41 process".

I'm doing mainly C-41 and some E-6... should I stick to the CPP-2 or will I be fine with
the CPA-2?

Cheers, Antonio