John,
One thing that is hardly ever touched upon, is the CRI (Colour Rendering Index) of a light source.
At the worst end of the scale is light sources like Sodium (low and high pressure) up to lamps like Metal-Halide and tri-phosphour(sp?) fluorescent tubes.
I think a few years back I wanted a discussion on this very subject, but it died, lighting has come a long way over the last couple of years, more lumens/watt and with a better choice of colours.
