I've heard of a couple of accounts where people claim to have gotten good results using a standard household light bulb in condenser enlargers. To say that I'm sceptical of this claim is an understatement. For a time, I used a condenser enlarger and have attempted to use household incandescent lamps. The experiment was a success. I learned that you can't cheap out on enlarger bulbs. There was a hot spot from the filament and the printing on the bulb's end was projected onto the baseboard. Not good. I don't want to see a negative image of "Sylvania 75W/120V" in the middle of my prints. Issues about color temperature are moot if you can't get an even exposure.
The suggestion to introduce some neutral density filtration into the light path is the easiest and most predictable way to cut down the light reaching the baseboard without changing the lens aperture. Rosco makes neutral density cine gels that are perfect for this application in densities of .15 (1/2 stop), .3 (1 stop), .6 (two stops), and .9 (three stops) that are perfect for this sort of application. See an example here: Dead Link Removed . They are inexpensive, can be easily cut to fit your filter drawer, and are heat resistant. I use the .3 density material and stack two sheets if I really need to cut down a lot of light. One sheet of .15, and one of .3 will cover just about any situation you might come across.