Weavers in Scotland make tartan fabrics for the production of OUTLANDER: The Series from 100% premium wool. The designer chose weathered and earth-tone colors common to the era depicted in OUTLANDER: The Series. The fabric for the production was specifically woven in a looser, more rustic weave, just like you would expect from the looms of the 18th century. In short, every effort was made to ensure authenticity.
 
About the Fraser Tartan from OUTLANDER: The Series
The Fraser tartan consists of colors grey, brown, gold, red, and black. The neutral tones of brown and grey take up most of the space in the pattern, seemingly imitating the expanse of stone and brown vegetation of the Scottish Highlands in winter. The small stripes of black are hardly noticeable, and the gold and red act as accents. You might recognize it as the tartan that Jamie Fraser wears for his wedding.
The Fraser tartan for OUTLANDER is modeled after the Fraser Hunting Weathered Tartan. (Available in homespun and light weight tartans.) The latter tartan consists of large expanses of grey and brown, and small accents of white and red. Hunting tartans are, in general, a more natural colored version of clan tartans. Because of this, they blend into natural environments, and camouflage the wearer. Weathered tartans tend to be a more faded version of tartans, because they often come in natural hues. When comparing the two tartans, one can see the aspects that the designer borrowed from the Fraser Hunting Weathered Tartan. He created a wonderfully calming tartan that lends itself well to the natural setting of OUTLANDER: The Series.