Colors are wonderful, but they were a by product of the surface hardening for wear resistance, and the softer, tougher interior. I've seen a Parker trigger plate that had great colors shatter during removal to fix the broken stock. Has anyone Rockwell hardness tested before and after ? What good are the colors, if the surface hardening is lost?
I suspect that was due to quenching at too high a temperature. The metal had converted to brittle Martensite.
What Turnbull is able to achieve, somewhat different from the other folks, is the correct color balance. I try to imagine the colors three dimensionally, first by identification of the "base", or the color that is prevalent. With Turnbull, it is obviously (and correctly) blue. If you look at others, that is not always the case. What I see is often gray or even charcoal. The other colors, although good, just don't look correct over a base that is clearly not blue. In my opinion, this applies to English guns as well as Parkers, the Base being slightly different for some other makes.
