Quote Originally Posted by dpurdy View Post
...My developer gets really old because when I heat it I am usually careful to pour it right back in the bottle and cap it so it doesn't evaporate between prints. Then when my volume starts to get low I add fresh developer to the old.
I could easily be wrong with this, but would not hot Potassium oxalate developer just (or mostly) give off water vapor when it evaporates, thus get stronger over time. If that is the case then one would just add some distilled water to "replenish" one's developer.

I'd like to know, because it is about time for me to bring my Potassium oxalate back up to its original volume after a long printing session through this past night and into this morning's light.