who "owns" a tartan?

[David Thorpe]

...exsample # I bought a kilt in Acrylic from clans men knitwear and they called it -
Ancient Ferguson and in fact it was different -Organge was bright hunter Organge.
and the measurement of line to line was off .

So be carefull what you buy from whom. I was happy thinking I was getting my family kilt
But got a knock off

Sett size varies with fabric weight. Lighter fabrics have smaller sett size due to thinner threads. Colors can vary from mill to mill weaving the same tartan. Neither necessarily makes it a "knock off" -- just an understandable variation. If the proportions or pattern of the sett are different, then it is a different matter entirely.