Ray wrote:
Murri,

I would think that you MUST have another source of light, as at a
distance
of six feet, a fluorescent bulb is of almost no value whatsoever.
Remember,
it's an inverse-square thing - twice the distance, one-fourth the
intensity,
three times the distance, one-ninth, et cetera.


The inverse square law applies to point sources. From diffuse sources
such as fluorescents, the fall-off in intensity is more accurately
expressed as the inverse of the distance.

(Think of a fluorescent as being a large number of overlapping point
sources)

Nonetheless, the fall-off is substantial. Six feet is a long way.


J. Del Col