"But you basic statement is incoorect when you say, "...if we think that the light from cfl's is pretty much junk after a few inches..."."

I base that off of comments that from 0-12 inches hps light is supposedly the same as far as what it gives the plant. Makes no difference if it's 1" or 12" the result is the same. Theoritically. But then move away to 48" and the benefit is far reduced. Only makes sense then that the further you move away OR the more/further the light has to be reflected till it gets back to the plant, the less benefit it will have. Yes, it may still have some purpose, or is it just overkill? By that I suggest that the plant may get all the light it can use through the direct lighting source and reflected light might just be like pouring water on a fire already extinguished. Doesn't put it out any more than it already is. Just wastes water.

It would be interesting to do some research, just to learn, to see what the lumens were at various distances on reflected light i.e. the light starts out at 10,000 lumens goes 2 feet and bounces off a piece of mylar and what are the lumens when it get's back to the point of origin? I now it may not matter, but when I get into something/anything...such as horticulture...this time...I start trying to figure it out way more than may be necessary to participate in whatever it is I'm doing. Just my nature. Probably why I've invented a number of "things" and made my living off selling one of those designs for 15 years. But of course if I told you what that product was, you might be able to figure out who "Marc Benson" really is.

"Having the reflection, that is impossible to get with black walls, aids in lighting the undersides of the foilage, and also penetrates the canopy."

Which of course means that side lighting IS of benefit. I've heard 'some' people suggest it wasn't.

Seems like light may be like an injector. It sprays a mist of fuel to be combusted but it's not just the most dense part of the spray (the direct light) that does it all, but also the tiny little micro particles of fuel (the reflected light) that combine with the main spray to get the job done (grow giant resin encrusted monster colas). And without the micro particles it just doesn't work as well.

But your comments make sense and I appreciate your time spent responding and your expertise.

Other thoughts? Yep! And time to go ponder many of them while studying the backs of my eyelids. Later.