From the blog "Bad Mood Rising"

Disclaimer:    It is common statment that painting yellow is dificult. Rhodes´Academy videos then try to convince us that it is not the case and that Contrast paints make wonders.  I am still undecided about that. In fact, I am facing some serious autoquestionning while looking at my latest paint job on tiny marines. I tried Imeprial Fist Yellow to go toward , guess what, an Imperial Fists´ 6 mm force.  I will not pretend calling them Imperial Fists anymore as it might be