Just to add my experience, I'm using the red E27-R24 bulb from http://www.superbrightleds.com as one of my safelights and I have no problems. The bulb is mounted in a much older safelight housing that I bought used, but I've removed the filter from the safelight housing. The result is much brighter than the light the safelight used to produce with a tungsten bulb, but it doesn't fog my paper. (I did a safelight test out to 5 minutes, IIRC.)