Somehow I get the feeling that the most of you are trying to produce black via profiles and color correction. If that's the case, good luck. There is no reason to invoke color correction on anything but bitmaps. Your rendering intents should be set to 'no color correction' or 'spot' on everything including gradients, except bitmaps, which should be set to perceptual.
Do this and you won't have to screw around trying to come up some some magic formula that whatever profile and color correction mechanism you happen to be using will end up interpreting as something you might like. Or not.
Black is still black, not purple, not green, but carbon black, the basic constituent of black ink and the definitive black. Unless, of course, you subject it to the ministrations of a profile and color correction mechanism.