re: bulbs "cheek-to-jowl"/ Mylar sources

> From: "A. Inniss" <andrewi at u_washington.edu>
> Date: Wed, 19 Feb 1997 23:54:06 -0800 (PST)
> At what distance apart do we stop having a significant lumen
> reduction?  

It depends entirely on the shape of the reflector.  Make a scale
drawing of the cross-section of your light setup.  Draw radial lines
from the center of each bulb.  Where a radial line hits the reflector,
draw a line leaving it at the same but opposite angle.  Where does the
line go?  If it does not go to the water, it's not adding much to the

> My bulbs are 1/2 inch apart: is that close enough to significantly
> reduce lumen output?

I think so.

> If so, I had the idea of putting some thin strips of tin between them,
> which i think will also help direct the light downward, right?

Do a drawing.