View Single Post
Old 11-09-08, 12:40 PM   #18
GenKreton
Lurking Renovator
 
Join Date: Sep 2008
Location: Cambridge, MA
Posts: 29
Thanks: 0
Thanked 0 Times in 0 Posts
Send a message via AIM to GenKreton
Default

To measure lumens from a light source you typically use a photometer which counts photos. It has a defined size on the collector, you measure a precise distance from the source, and you need to know the directionality of the light (simply defined as the percentage of a sphere for elementary cases) to get your unit of lumens. So lumens has no accounting for the frequency of light.
GenKreton is offline   Reply With Quote