Nice job. I've been messing with my Karve as well using some household mixtures, most with ammonia and salt. I could not get the blue and green as you did. With a brass razor such as this you if you don't like the patina you can start again with a vinegar and salt mixture, then polish.
I'd like to know how you can lock in the colors after you've got the patina correct. I'd think it's a renaissance wax or inert. I don't think I'd want to use a spray laquer.
~Bill