Linen is a cloth made from yarn of twisted flax fibers.
The Shroud of Turin is a single length of linen cloth. It measures about 14 feet by 3½ feet. The weave is a three hop (3 over 1) herringbone twill. It was made on a hand loom.
It is approximately 350 micrometers but it varies slightly. The range is between 315 and 390 mm. For comparison, a sheet of typical 20 lb. copier or printer paper is about 100 mm thick.
The yarn (thread) consists of approximately 70 to 120 flax fibers twisted together in a clockwise Z-twist. The various lengths (hanks) of yarn are not spliced together but laid in side-by-side during the weaving.
Variegated patterns, known as banding, in both the warp and weft yarn, suggest that the yarn was bleached before weaving rather than after the cloth was taken from the loom. This is a significant clue to the age of the cloth because medieval European linen was field bleached, a process that eliminates banding.
The thickness of the fibers from flax plants vary significantly as they do in the yarn of the Shroud. The average thickness of Shroud fibers is about 13 micrometers or 13,000 nanometers. For comparison, a typical human hair is about 100,000 nanometers thick.