Blade finish on carbon blades?

[koger]

I have seen several new carbon blades made by custom makers at gunshows and such, all have a thin brown finish on them, looks like plum brown for muzzleloaders. Anyone have a clue as to what this is, application, thinking of trying this on a few blades.

[gables]

I'm not sure what it is but assume it is a rusting solution like plum brown. I have been seeing all sorts of etched, blued, etched and blued and parkerized blades at local shows.

I just used Brownell's Classic Rust Blue but boiled my parts after rusting which gives a black finish. Someone recommended the Laurel Mountain brand for my next time. That solution has a built in degreaser and seems a little easier to use than the Brownell's formula.