Thank you Barb for participating in the discussion. Since the true question was "What defines a tartan as a tartan?" She had all the information she needed based on a random image to go by. While the intention of the weaver was to make a tartan, by his mistake in coloring, the pattern ceased to be tartan and became plaid as per Barb's explanation. Don't take this as an insult to the kilt or tartan.