Quote:
Originally Posted by mrerick
See: https://en.wikipedia.org/wiki/Bluing...)#Niter_bluing
"the colours will range through straw, gold, brown, purple, blue, teal, then black."
Obviously, this bluing process was not used for the traditionally strawed parts of a Luger, but it was used on the grip screws. |
I'll keep arguing that "nitre" is not a bluing process; the "nitre" salts are only used as a not so convenient way to heat the "white" metal.
The color change arises from the heat- not the salt; the same result can be obtained by heating in air, or in any other medium- sometimes even molten metal has been used.
As the Wiki said, the object must be watched carefully as it is heated in the very hot salt bath, as the color will change from "white" to "black"(actually more grey)- if left in too long- passing through the various colors on the way.
This chart has been posted many times: