If I'm not mistaken, Taylors & Co are an importer of Uberti. I had a SAA that I engraved with their name on it, they are usually "higher end" Ubertis as far as finishes, details like martial inspection marks and so on. They are chemical colors and wipe off with toilet bowl cleaner on a cotton ball.
Even regular color case hardening will discolor with toilet bowl cleaner. Toilet bowl cleaner is phosphoric acid. Many engraver use it to take off case colors or bluing and produce what is called french gray. I am engraving a Uberti colt now and the case hardening is fake. I can't say for sure what Pedersoli is.
to better show the engraving?* also, "color hardening" can be, and often is, just used for the case hardening effect on the steel, not for the color. in fact, it could be said that "case colors" are merely a serendipitous side effect of certain methods of case hardening. so while many guns have been case hardened primarily, even solely, for its decorative look, that was not its original purpose.
*someone once told that when it comes to bad engraving, "a multitude of sins can be hidden with a good color hardening job".
Colors selectively polished off JJ...leave it where you want it and remove it where you don't. A process used by many. Phil Coggan does it a lot. The hardening is what is important to make delicate engraving much more sturdy.
Polishing the color off of true heat method case hardening and back to white metal is a method of creating a Coin finish.
Just like many heat hardened tools and gravers that are in the white, it is pretty rust resistant.
To engrave a clean canvas of course. In my case the finish on the metal needed to be better to boot so after I engraved it, I sent it to Turnbull for real color case hardening as it was as soft as butter to cut. Just mild steel.