I have 2 drying racks in my room and to help when I know space will be at a premium I use this simple sign. This way art goes below the sign, helps me put more than 1 class on a side or prevent paintings from being pushed in the rack over the student's head.
Suggestions - Print it on cardstock - to be heavier. I laminate mine - in case it gets paint on it. Fold it in half so one end will sit on a drying rack shelf and the arrows will point down.