Got to say out of all my Batiks in my stash ( alot) , I do not have a single peice that would "read" black solid. I do have a smaller collection of black batiks but they all have other colors to give them more character. I doubt that I would really use a Black watercolor like Hoffman ( 1895) or Kaufman makes. It would probably be my last choice. But I can see it having its uses , in limited amounts.
IF I did have an occasion to use it , believe it or not .... I would look for a true solid ..... and a poly blend ....a poly blend holds its color better than a 100 percent cotton. Can't tell you how many pairs of black cotton pants i have because they are not black ... really black for too long.