This is a k80 dated early 1990s. It has been annealed. I visited with Kreighoff at SCI and they said around 2001 they changed steels and it would be very tricky to anneal post 2001 K80s. This one is cutting well. A touch hard but cuts clean. K80s unannealed are in my opinion unengravable.
The coloring is serendipity mostly. I threw some cold blue paste on it to try a few different things and it turned blue in the water by the flamingos. Just plain dumb luck.