I found a hd tv curbside last week. A 57" sony rear projection 1080i tv. after getting it home and adjusting the green gain a bit to remove a bit of retrace line. we started noticing that it was very bright to watch at night. so i instinctually tossed a 4' T8 floresent light behind it to add some backlight. Later found this to be called "biased lighting". I then went and bought a 4' T5 setup from depot to hide the fixture a bit better behind the tvs bezle. But i got to thinking about how bright the back light should be. Are there any guidelines on this? I read one artical where it stated ambient light should be no more than 10% of the brightest white. But i don't know if that includes bias lighing.