TUBES are GREAT!
Natural lighting can do wonders for a dark room. And most products
offer dampers which allow you to control the amount of light coming
from the tube. Huvco offers the best diffuser I have seen. ( I have
four in my home office.) I swithced out the original two, to the Huvco
diffuser.
www.huvco.com
Check them out, they come highly recommended.
Tobin.