False color

Hi Everyone,

I just have a question about the False color. I noticed one of the slots says "conversion factor", which by default it's set in 179, What is this exactly and why would I want to change it? I do notice it chtanges the scale of Cd/m2 in the final image, but i did some tests, running the false color twice with different conversion factors and the image stays exactly the same despite of having different scales so again, Why would I want to change it? Which factor is giving me the correct results? (I guess it's 179?). 

Many thanks before hand,

Mikel