Thank you soo much for this. It's really gonna help

Heh, normaly I make my lineart on a blank layer with white under it. But this helps for when I have to use pre-existing line art. I just tried it as a test, and it works well. Though the image is darker, I selected empty space and deleted revealing there was a very faint colour there masking it. :S
Oh well, thanks. This should help me develop some nice tricks, I hope