It’s nothing compared to the brightness of outside (even on a cloudy day) unless you stare directly into the soul of the corncob.

They’re actually 13W or so? I use a 7-way splitter on 4 bulb slots made for higher watt incandescent bulbs. That helps a lot, then use a corn bulb I bought that uses 100W and puts out 10,000 lumens. It still only gets the room to 7,000 lux, which is less than a bright day. My Lux meter clocked 50,000 lux streaming through the window in October!