For those who might be interested in the origins and process of the "Royal Blue" finish on Colt handguns, Mr. Adalbert (Al) Gunther, superintendent of Colt firearms back in the day and the man credited with the creation of the Python revolver, had this to say:
"...(The Royal Blue finish) was the first really super-deluxe finish Colt ever put on a production gun. Contrary to popular belief, we didn't blue the Python with any different formula than we used on the other guns. Polishing was the secret. We used old fashioned wheel polish, beginning with about an 80-grit emery, and progressing to 120 grit, 320 grit, and finally 400-grit emery. 400-grit emery is the consistency of flour. This would be applied with a leather top wheel- Colt always made their own four-inch-wide, old fashioned leather polishing wheels-and that 400-grit was so fine that when you were using it with some grease you couldn't see any sparks at all from the polishing wheel. To the best of my knowledge, that's the method Colt still uses to put the Royal Blue on the Python, the Gold Cup and some of the special Single-Actions. Royal Blue was the name they gave to the finish we created for the Python, but even today, around the Colt plant, they still refer to that ultra-polish job as the 'Python finish'..."