Nikon SLR Cameras

What do the colors on f-stop numbers mean on manual lenses?

klay d
klay d

I have a Nikon FM-10, and on the 50mm lens there are colors on some of the f-stop numbers

Specifically
22-pink
16-blue
11-green/grey
everything below that is white

Lia
Lia

My instructor told us that the lower f-stops are sometimes orange or pink because you can't handhold the camera at those settings.