Honestly, I'm trying to figure that out myself. As John likes to point out, I'm a novice fancier rookie
This is my first year mating these birds, and all I know is that my hens are light, with weak edging. That's why I'm using black, in hopes of darkening the blue and giving a more pronounced edging. Oz's chicks are showing strong edging, I just hope that as they age they aren't so dark that the edging blends in with the rest of the feather. That's why I'm really curious to see Susan's blues when they start filling out. It looks like we have the two extremes, and one may be better than the other, or the optimum may lie in the middle. That's the great thing about this forum. We can compare and share information