The Clark/Clergy tartan seems to be woven with more variation in colors (actual colors in the thread count vice different color schemes) than any other tartan.

The tartan pictured above appears to be the "Clark" tartan as woven by Lochcarron. The thin cross stripes are white. Lochcarron weaves the same design as clergy but the thin cross stripes are rendered in blue. Strathmore weaves a variation with the thin cross stripes rendered in green.

My guess is Lochcarron has done this in an attempt to differentiate the "family tartan" from the "occupational tartan", although my understanding is that the origin of both tartans is the same.

Cordially,

David