I was in my lighting design class (theatrical) the other day and someone asked why when we sharpened the hell out of an Source4 light there was a blue edge to the light, and no one knew why it happened. I thought i've seen that in photographs when you zoom in enough you can see this blue ghosting along sharp edges. Now my question is, is that caused by the glass or some other weird thing. I know its weird and probably poorly worded, but I was really just curious.