capt cynical is not far off the mark.
i am partially colour blind, found out at the f/a interview!.... no problems.
a mate in my training school sees black, white and grey.
the only colours we deal with are o/head indicator lights which are easily memorised plus they are supplemented by chimes...more than one chime... grab an extinguisher.
meal choices have different coloured lids and even if u make a mistake most of the punters can't tell the difference. this i know from my own stuffups