Most bluing I have seen is actually a black/blue or todays guns black
Last night I watched the movie Appaloosa and the 8 gauge punt/shotgun was a vivid blue that glowed especially when set down on the marshals office. Several old guns I have seen this bright blue color on older rifles in museums. I assume this was a rust bluing? The only bright blue hot blued guns I know of was the colt anaconda/ python but the cost to set up hot bluing is not worth it but the rustbluing other than the carding wheel look very doable since I have everything else already.
I have fireblued screws to get that color but what is the trick to rust bluing to get that color? Is it a specific solution?