Karl,
I can't tell you much about the blacking solution other than I got it from a gun smithing shop many years ago. Its just a thin light blue liquid that I applied with a swab until it looked right. Then I washed the piece and rubbed down the petal edges with 2000 grit to reveal the pattern. Not very technical I'm afraid but it seems to have worked.
The photos above show the piece with no protective finish. As most of us on here know how to look after damsacus steel its not a problem left "as is". As this will be sold I have warmed the piece up and applied bee's wax. Its an excellent way of protecting the steel and has the advantage of getting in everywhere. The downside to this and a laquear finish is that the topography of the pattern tends to blend into one flat surface.
The photo below is with the wax finish,
Mick.