I got a reply from them and I am not that happy.
QUOTE:
Color is subjective and you would be hard pressed to find the definitive
BLACK in a fabric. Our company is not large enough to buy our own
specified dye lots so we buy what is available from our supplier and - as
a result - some blacks come in slightly blacker, grayer, bluer, greener or
any other shade. But it is ordered as Black and sold as Black and - at the
moment - it's the only black on hand. We don't make Navy Blue AmeriKilts.

Well they sure have someone buying fabric that is a little color blind I dunno maybe it will be nice to add this warning on their site?...Oh well...