Vern,
A good start, but headed in a slightly wrong direction.
--------------------------------------------------------------------------------------------
Halo: Encircled with or as if with a halo.
Halo is an effect seen associated with the stamping of blued steel after the bluing has been applied.
Compression of the steel surrounding the stamping, possibly changing its crystalline structure, alters the appearance of the bluing of the affected steel, making it appear lighter and "washed out".
Sometimes the steel at the edges of the stamp is displaced upward.
Halo is one indicator of authenticity of finish on a Luger pistol. Certain markings are known to have been applied after the blue, and these marks usually will display halo. If a gun is refinished, the area of compressed steel will accept bluing as any other steel, and the halo will be eliminated. Any steel displacement will be smoothed out in the steel preparation process.
---------------------------------------------------------------------------------------------
It would be interesting to see an actual metallurgical explanation of the phenomenon.
--Dwight
|