There's a lot of confusion about the various names for Colt's bluing.
Part of the confusion comes from writer's bandying around different terms like "Blue", "Bright Blue", and "Royal Blue"
Even the factory used different terms, sometimes calling the Python blue as "Bright Blue" Deep Blue, or "Royal Blue".
In later years Colt usually used "Royal Blue" in it''s literature.
Inside the factory, the workers still refer to it as"the Python Blue".
There were NO different blue finishes for the Python, but many people say the later guns didn't look as good as the older guns.
Suffice to say, that the Python had the finest production blue job possible from 1955 to the early 2000's, whatever it was called at the various times.
To further confuse things, Colt used the same general terms for the non-production Colt Custom Shop ultimate blue finish for the absolute top-of-the-line custom guns.
Colt also had: standard blue, Trooper blue, service blue, Official Police blue, Fire blue, heat blue, charcoal blue, and matt blue depending on the era.
I have for sale, (for a limited time) a rare Colt revolver with a Colt Royal-Mega-Ultra-Fire-Acid Blue finish.