JOBO CPA-2 temperature controlgreenspun.com : LUSENET : Large format photography : One Thread
I want to get a JOBO processor to process 8x10 film and 120 film. Can anyone give me an asessment of the CPA-2's ability to control temperature. Most of the fall, spring, and winter the darkroom is cool, but in the summer it can run to around 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?
-- Steve Williams (firstname.lastname@example.org), July 02, 2000
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.
-- William Marderness (email@example.com), July 02, 2000.
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.
-- Mike Kravit (firstname.lastname@example.org), July 02, 2000.