If not already installed I'd buy pre-colored sticks of EMT.
It is very common to color code for example fire alarm circuits red, life safety orange, critical green, equipment blue, normal neutral or some other color combinations.
I've worked on a few projects that contained baffle ceiling systems with EMT conduits located above. We were instructed by the architect to include verbiage on our drawings that required the conduits to be painted black. The projects were located in a rather stringent part of the United States, from a plans review and inspection perspective. There were no issues with the installation, as far as I can recall.