Hans
Diafine has two solutions - A and B.
Sol. A is the developer and is slightly acid, so there's (almost) no development going on in it (this is very true at 20 C).
Sol B is alkali+sulphite, and that's where all the development takes place.
Myths and Facts:
Diafine IS temperature dependent (not much, but contrast and grain increases with temp. I use it at 20 C).
Some films are way overated (PX @400 - I did not like it).
It's an extremelly compensating dev - so if it's a low contrast scene, neg will be flat.
But TX @1200~1600 gives very good night, artificial light and flash photos (high contrast scenes).
HP5+ @800 wasn't bad, also.
If you care, I can post the formula I'm using.
Jorge O