Sir,
Not all things in the services are common sense or obvious.
I just grew up associating various colors with certain things.
ADRP 1-02 (the old FM 1-02 Operational Terms and Graphics) has the following - document approved for public release, distribution is unlimited:
COLOR (FILL)
3-7. In framed symbols, color provides a redundant clue with regard to standard identity. The fill is the
interior area within a symbol. If color is not used, the fill is transparent. In unframed symbols (equipment),
color is the sole indicator of standard identity, excluding text amplifiers. Blue for friendly or assumed friend,
red for hostile or suspect, green for neutral, and yellow for unknown or pending are the default colors used
to designate standard identity. Affiliation color without the fill may also be used for the frame, main icon,
and modifiers.
https://www.hsdl.org/?abstract&did=789196 I don't currently have access to the Joint Pub, so you'll just have to trust me on it being a NATO standard.
On a side note, we currently depict Afghan units as green. So, nothing is written in stone.
Regards,
(Yes, I am sure some staff officer somewhere got a medal for coming up with a new acronym for the FM series publications . . . .)
