When did navy blue become so?

Hey, choupette! Great to see ya.

My theory is that the exact (British) Navy shade of blue didn't exist before it was introduced in the Navy. Or at the very least it effectively didn't exist, as it wasn't separated out from other shades of blue.

I always think of navy blue as a very dark blue that's near-black except in good light. Indigo definitely isn't right, and I don't think purple is either - it's just a very very dark blue, simple as that.