99% of the fabric we get from MM is color fast (nothing will bleed in the wash). I ONLY noticed this b/c my fingertips were turning blue after sewing up the first XMARKS PV kilt.

Sydnie brings up a good comparison... when you get a new pair of 'indigo blue' colored jeans, you need to run them through a cycle all by themselves. Ditto for the XMTS tartan.