Quote Originally Posted by cliveh View Post
This has probably nothing to do with your equipment, but a difference in developer temperature and ambient temperature difference.
I process prints in a Jobo at 24C. If it's consistent enough for E6, it's more than consistent enough for B&W prints that are developed to completion. And in fact the ambient temp was higher on the day with lower density.

Quote Originally Posted by ic-racer
Variacs are pretty inexpensive. You already own a voltmeter. If it is day-to-day variation in the line voltage then just set your voltage with the variac at the beginning of each printing session. As you probably know, the automatic regulated power supplies that will keep the voltage fixed will be pretty expensive.
A variac actually turns out to be $$$ in AU, even compared to a switchmode supply

One nice thing to discover from all this though is that a normal photographic incident-lightmeter serves (with the dome removed and the photodiode exposed) as a perfectly good enlarging meter. You just need to ignore the absolute readings and work in differences of stops. I reckon I'm going to have to write down a couple of tables of print zones vs meter readings, which should save me a shirtload of time on test strips. Certainly saved me a bunch of time the other night when printing one image at three different sizes.