One basic thing I'm not too clear on, which I would like to be clear on, is the brightness per mass unit of GFP or luciferase. I was having trouble finding a resource that would state the brightness at least for standard GFP or luciferase per gram, for example. Is there a basic rule for the maximum brightness for either of them? I'm aware this might end up being a vague question, but I could use help clarifying this. I found brightness as a product of the extinction coefficient and quantum yield but I wasn't sure how to translate that to watts.