In my last NOTD post I wore Formidable! (not CF) and because of the streaky formula I wondered how it would look over black, so here are some photos of this:
And here it is again alone on my fingers:
As you can see the colour is a lot less brown and instead more of a deep plum. It just looks like a soft black with green shimmer in it, which I quite like!
Putting it over black definitely helps with the formula issues, although when I applied Formidable! it smudged the colour underneath slightly even though it had been dry for ages! I find it quite surprising how different they look actually.