I've tried this with two small enlargers, a small Bogen enlarger (up to 6x6 negatives) and an Omega B-600. Both have condenser type lamphouses and on both the experiment failed to produce an acceptable result. The spiral pattern of the bulb is clearly visible on the baseboard with the negative carrier, containing a blank piece of film, in place. Different machines may produce different results, so you'll need to experiment for yourself. Aside from that problem, there is the ramp up and ramp down effect of these lamps. It can take a good 30 seconds or more for the lamp to reach peak output, and there is after glow once shut down. Leaving the lamp on for the entire printing session is often not practical. I've yet to see an enlarger that does not leak some light. Once the lamp warms up, it reaches maximum output quickly; but nowhere near as quickly as an incandescent lamp.