I don’t see why an LED lamp shouldn’t work. In general I have replaced some room lighting with these and a 7 Watt LED is as bright as a 50 Watt. They also look whiter and are much cooler. Students don’t just have enlargers on for longer periods of time when dodging etc. They often just leave them on and leave the darkroom. You could cook an egg on some of those enlargers after a few minutes. I have never tried an LED bulb in an enlarger, but it may be worth experimenting.