CPP-3 Question

I am curious as to why the default programmed processes for B&W are set to a temperature of 24 degrees and not 20 degrees. What is the rationale for this?

Of course I can just add my own custom process with what ever temp I like, but it just seemed kind of odd (similar to their naming B&W processes "B/W 5"and "B/W 7" with the times of development - 5 and 7 minutes, respectively- while process B/W 15 has a development time of 10 minutes ).

thx

The ambient temperature needs to be lower than the set temperature for it to work. Not many people have darkrooms lower than 20C.

I've never used the stored times on my CPP3, I should. I just have been using a Gralab timer for 40+ years.

Jobo maintains temperature heating the bath, there is very little control with the solenoid cool water entry. So keeping the water bath at 20° C is difficult, and harder or impossible as it gets lower.

ic-racer said:

The ambient temperature needs to be lower than the set temperature for it to work. Not many people have darkrooms lower than 20C.

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Thanks!

Luckily, the ambient is usually lower than that in my basement.

So your view is that Jobo programmed the temp to 24 based on the fact that people will usually have to deal with higher temperatures? It is interesting that they would do that given that 20 degrees is close to a standard. But that is probably not a bad idea for a manufacturer to go with when selling a product that will find itself in diverse environments.

I don't think the default programmed processes are editable, so I will just input my own where needed.

mshchem said:

I've never used the stored times on my CPP3, I should. I just have been using a Gralab timer for 40+ years.

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I have used a couple of times so far and I find them very convenient - I recommend giving it a shot!

halfaman said:

Jobo maintains temperature heating the bath, there is very little control with the solenoid cool water entry. So keeping the water bath at 20° C is difficult, and harder or impossible as it gets lower.

Click to expand...

I wont hook up the cold water, since lowering the temps has never been an concern for me.

I recall that a friend put a frozen water jug inside the water bath of a Jobo CPP3 so it is constantly heating it. He had the jug size "calibrated" so he was able to maintained constant 20° C during the whole development time even in summer.