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Cloudy Days

PostPosted: Mon May 03, 2010 1:46 pm
by Dyno
I was wondering what the impact would be if the sun did not shine, if there were clouds, what impact this might have on exposure times. I could not find a reference to this in George;s book, but I found this document:

uvb.nrel.colostate.edu/UVB/publications/uvb_primer.pdf

Looks like if the cloud is light then about twice the time is required, whereas if the cloud is heavy, then forget it and head for the D3 bottle !