I'm making a belt at the moment using Fiebing's black dye. I'm used to this stuff rubbing off, but I find that it looks OK when viewed on it's own, but if it's in strong light, or when viewed against a factory dyed black leather it doesn't look completely black, more a dark brown colour. Am I being picky? Does anyone have any suggestions? I've tried a little neatsfoot but it doesn't seem to have made much difference. I heard it's possible to dye the article blue first, then go black, does this work?