Eric,

I have never given it much thought, but as radiance is the light intensity
emitted from the source, while illuminance is the light reaching the target,
I would think the latter would be more appropriate, but is it that
significant of a difference? In any case, there is simply no way you should
be seeing 7000 fc through an 80% shade cloth, as that would imply an
unshaded intensity of 35000 fc!

If I remember correctly, noon on a midsummer day will give about 10000 fc,
depending on your latitude, so through the 80% shade you'd be looking at no
more than 2000.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies, Artwork, Books and Lots of Free Info!


"Eric" wrote in message
oups.com...
Hi everyone,
I'm trying to measure the foot candles in my shade house. I have 80%
shade cloth but when I measure the radiance its still about 7,000 fc.
Should I be reading the radiance of the illuminance? This is really
bugging me. Thanks in advance for any suggestions.
Eric