Yarn Barn of KS. The ground warp is a 40/2 linen like the earlier towels, and the Barrett article calls for unbleached.
I was so intent on trying to explain the draft in my last post, I neglected to mention that this towel is set at 30 ends per inch, just like all the previous towels so far this year. At least, the linen ground warp is at 30 ends per inch, and the total linen ends are 570 ends for an in-reed width of 19". In the colored pattern stripe areas, the pattern warp is a supplementary warp - that is, it is not a part of the basic plain weave ground cloth that the linen forms - so it goes in right on top of the 30 epi linen, one pattern thread per ground thread. So in the pattern areas, the sett is actually 60 ends per inch.
I wound and beamed this pattern warp separate from the ground linen. For most of the colors you'll wind a few ends, then cut and tie off and start the next color. But if you're using a warping board or pegs, for colors that repeat near each other like all those greens in the center of the main stripe, you can set the yarn package aside while you wind the other colors if you like, then return to the color set aside as you need it again.