From Jocasta Nu (Jedi Librarian/Archivist) at the official site: Question: In Episode II there appears to be troopers with a color-coding on their armor. Does this indicate rank and if so what color equates to what rank? Answer: It is indeed an indication of rank. Yellow markings indicate a commander. Red clone troopers are captains, blue are lieutenants and green are sergeants. Now I know what rank my action figures are!