Board Thread:Questions and Answers/@comment-24578309-20140608193942/@comment-1317092-20140610220734

Not sure if it counts as this thread is about the Nick animated series, but the Archie Comics used the explanation that Splinter gave them the colored masks to differentiate them, and even implies that he took the idea from a discarded Donald Duck comic he found in the sewer (I guess Splinter, being a mutated human in the Archie and Nick versions, must have had the same problem as us to distinguish four mutated turtles, at least at first)