As far as I can tell from extensive readings of the "Daybooks" Weston made most of his 8x10 contacts on Azo with his print frame in sunlight. Azo is POP (printing out parer). Considering that the sun and a condenser are both pretty much point sources..a bare bulb would probably need to be focused a bit more. Try using a reflector with the bulb..or even a reflector spot. Beware of printing on the bulb coming thru on long exposures