I have no expertise in electrical engineering, but have wondered about this for a while. Would there be any benefit(s) to running an enlarger lamp on 12-volt DC current only? Like marine or RV vehicles do it?
I would think that an inexpensive automobile battery and a trickle charger to keep it topped could easily handle a normal darkroom session. The bulb would not be subjected to the normal AC current swings. There would be no power grid fluctuations to mess with those delicate highlight values. And heck, if you used a mechanical timer you could even print during power outages.
But would the bulb last any longer?
[Edit: Oops. I see that 'bernard_L' already mentions this in passing in post #6...]