I just picked up a couple of "flamed titanium" pocket clips, and I love the look of them. I've always been attracted to the blue-on-black color combo for most things I own, and I love the way the color pops on my Vision FG!
I've noticed, however, that even the slightest touch from my fingers will dull the shine and really mutes the color. It comes right back with a simple wipe on the clip with any dry cloth, but it's a little annoying just how well this finish attracts skin oils.
I was thinking about picking up some flamed ti scales to go with this, but after seeing how quickly the color fades after being touched, I'm not sure how I'd feel about an entire handle with that finish.
The color exhibited by anodized titanium is due to the refraction of incoming light by the oxide layer on its surface. This works exactly like how it does on some butterfly wings. The surface isn't colored per se, but rather the nanoscopic texture on the surface interferes with the light hitting it and bouncing off to produce a reflected color. Anything that fills in, changes, or alters the reflective index of the surface will alter its appearance, like any grease/finger oils/moisture/whatever until it's cleaned off. (This is why anodizing titanium, unlike aluminum, does not require any dyes to produce a color. And you can influence the color depending on the voltage at which you anodize it, which is wild.)
This is just how anodized titanium works. If this annoys you, a larger piece of it is likely to annoy you as well.
Whoa, I had no idea about butterfly wings! Thanks, I have a new rabbit hole to dive down now. :)
It is pretty wild from a scientific standpoint. The clip on my Benchmade Morpho exhibits the same phenomenon, since it's titanium and it's anodized blue. The liners do as well, actually, but they're harder to touch since they're recessed under the scales. Whenever I take it apart to deep clean it you can noticeably see the color turn more blue. When these parts are smudged they tend to become a dull grayish purple.