Well, that's what splash is. Usually one predominant color with "splashes" of other color seen on the feathers. The birds usually have only one color that splashes, but in theory I suppose you could have more than one splash color although I have never seen it. Not sure about that....
The black should be pure, but possibly will lose some depth of color over successive molts.
I had a beautiful dark blue bird that over time has become almost a splash, so genetics can be iffy at times :)
Not sure what you mean by "pure" splash since they are a mix?